WO1993017481A1

WO1993017481A1 - Automotive power distribution and switching system

Info

Publication number: WO1993017481A1
Application number: PCT/NZ1993/000009
Authority: WO
Inventors: Pita Witehira
Original assignee: Pita Witehira
Priority date: 1990-05-16
Filing date: 1993-02-24
Publication date: 1993-09-02

Abstract

An automotive battery switching and distribution system which includes a battery system in combination with an integrated power switching system, for providing protection for the battery system by synchronizing the battery system's discharge rate with the electrochemical reactions of the battery system. The battery system has at least two discharge characteristics, one capable of short high current discharge of electric power for cranking an internal combustion engine, and the other for providing a lower rate of current discharge as required for vehicle auxiliary power. The power switching system acts in response to increased voltage or current levels to connect or disconnect the battery with related loads or power sources as necessary for optimum battery protection and system operation. Each portion of the battery system is separately connected to the electrical system of the automobile so that draining one portion of the battery system will not affect the electrical system that is connected to the other portion of the battery system.

Description

AUTOMOTIVE POWER DISTRIBUTION AND SWITCHING SYSTEM

TECHNICAL FIELD

The present invention relates to Automobile Electrical Power Distribution and Switching Systems.

PACKQRQW AP

The prior art discloses conventional automobiles utilizing internal combustion engines started by electric starter motors. The starter motor cranks the engine and an electrical ignition system. Power for cranking and ignition is provided by a lead acid storage battery commonly referred to as a Starting, Lighting and Ignition (SLI) Battery. After the engine starts, the vehicle's battery is recharged by a power generator driven by the internal combustion engine. The power generator in modern vehicles utilizes alternating current for efficiency. The alternating current is "rectified" to provide direct current to most electrical consumers throughout the vehicle. The direct current also is used to re¬ charge the battery. The charging unit of a modern vehicle is commonly referred to as the Alternator.

The alternator usually provides sufficient current to run the electrical consumers when the engine is operating. The battery acts as a "load levelling" device to ensure smooth and constant direct current throughout the vehicle's electrical network.

When the vehicle's engine is not operating, power to the various electrical consumers must be provided by the SLI battery. For safety and other reasons, the SLI battery should provide a minimum amount of reserve power to operate the headlights, ignition and window wipers. For example, if the alternator of the vehicle should fail at night, while it is raining, the vehicle's SLI battery should provide a minimum amount of power to operate the vehicle's lights, wipers, and ignition system for a specified period of time. Preferably, the user should be able to drive the vehicle for between 30 and 100 minutes with a failed alternator.

Worldwide standards have been established to measure an SLI battery's "reserve capacity" for supplying electrical power to important consumers when the alternator system fails. Generally, the vehicle manufacturer chooses a particular SLI battery based upon established standards applied to a particular vehicle's full specifications and electrical load requirements. An important safety consideration regarding the vehicle's battery capacity is the amount of power provided by the battery during times of emergency. In times of emergency, the vehicle user will normally activate park lights or hazard lights as a warning to oncoming traffic. The vehicle's engine may not be operable at this time. The SLI battery must therefore be capable of providing electric power independent of the alternator for safety functions.

Another aspect of modern vehicle electric power requirements results from an ever increasing demand for "key off' power to low current consumers. The SLI battery is subjected to an increasingly higher power discharge, independent of operation of the engine, because modern vehicles use an ever increasing array of electronic devices ("key off').

Conventional batteries are often damaged by slow, long discharges caused by the ever increasing number of key off loads. An extended period of slow discharge may force the battery into a state of deep discharge which in turn may cause irreversible damage to the electrode plates because they are designed for short shallow discharge.

Due to an increase in electric power demand, conventional vehicle electrical systems are poorly suited for modern vehicle use. Indeed, worldwide statistics indicate that battery failure is the most common cause of vehicle breakdown. SLI battery failure causes between 20% to 50% of all emergency breakdown incidences throughout the world. The next most common breakdown cause represents less than 11% of all emergency breakdown incidences.

Clearly, the conventional SLI battery is unacceptable for safety reasons, and must be re¬ designed in order to be made more compatible with modern automobile demands. It is possible to provide a battery with reserve back-up power to re- start a vehicle in an emergency. These batteries, known as "dual", "switch" or "2 in 1 batteries", provide emergency back-up power in the form of a reserve battery. However, dual batteries do not solve the problem of battery incompatibility with modern vehicles' electrical requirements. Most dual battery systems are designed to provide cranking power in an emergency only. Unfortunately, such batteries are inefficient unless integrated into the vehicles' electrical network.

The conventional SLI battery is in fact a design compromise. Although it is able to provide some reserve power at a slow rate of discharge for emergencies, i.e., when there is alternator failure, the SLI battery is primarily designed for short rapid discharge as is required for starting. Deep discharge of the conventional battery results in damage to the electrode plates which may become permanent.

Under some conditions, an automobile's electrical system is incapable of supplying sufficient power to service the ever increasing number of electrical consumers. Although it is possible to increase the output of the alternator, inevitably the increased capacity of the alternator is consumed by the addition of more electrical loads. Such a condition is known as "deficit charging." Deficit charging occurs when the alternator is unable to provide sufficient power to re-charge the battery. Due to low engine speed and high electrical consumer demand, the battery must provide back-up power. If deficit charging continues for too long of a time period, the state of charge of the battery falls and a consequent voltage drop results in engine stalling.

Another example of the incompatibility between modern vehicle power distribution switching systems and battery charging systems is demonstrated by the relationship between alternator and battery. Modern automobiles employ charging systems using alternators that are integrated with a rectifying diode system and a voltage regulator. The alternator is driven by the vehicle's internal combustion engine and is located relatively remotely from the battery. As the alternator's temperature increases due to the running engine, the efficiency of the voltage regulator is reduced. The rectifier and the voltage regulator temperature eventually shift out of synchronization with the electromechanical requirements of the battery due to a variation in temperature between the voltage regulator and battery electrolyte. This phenomenon results in sulphation of the electrodes and a lower state of charge.

Many attempts have been made to provide an improved vehicle battery and electrical power system. Since automobiles have relied on batteries to provide power for lighting, and later starting, automobile batteries have been continually refined. Necessitated by safety and reliability concerns, electrical networks and switching systems have continued to expand providing more power to more consumers. What were once luxury items are now standard equipment. The electrical harness has accordingly become more complex and expensive. Demands on the SLI battery have increased significantly. As a result, the battery is unable to cope with increased power demands and now represents the weakest component in terms of emergency breakdown incidences.

Attempts to overcome the problem of "accidental battery discharge" are made by Pacific Dunlop's GNB Switch Battery and Johnson Controls' Dual Start, USA Patent No. 5,002,840. Both the Switch technology and the Johnson Controls dual start systems only provide emergency starting capability. These systems cannot be relied upon to solve the long term problems associated with the incompatibility between vehicle battery design and electrical system demand.

Electrical power distribution systems in automobiles have evolved around the limitations of the SLI battery and charging systems. This has resulted in very complex, expensive and heavy electrical networks which are inefficient and incompatible with battery electrochemical reactions. Therefore, there exists a need for a longer lasting battery system for modern vehicles which includes a synchronized power generator and load shedding system.

Under certain conditions, e.g., when the alternator has failed, it is necessary for an improved battery system to provide emergency power to the vehicle. Under these conditions the battery must be capable of simultaneously providing both high current, rapid discharge power and lower current, slow discharge power to the vehicle. Short duration, high current discharge of electrical power is necessary to crank an internal combustion engine under emergency starting conditions. Alternatively, a long duration, low current discharge capability is necessitated by an ever increasing number of low current electrical consumers.

Additionally, the voltage output of the alternator charging system must be synchronized with the electrical and chemical reactions of the battery. To prevent battery failure, it is necessary to prevent charging the battery when it reaches excessive temperatures. Therefore, the sensor that detects battery temperature should be located in close proximity with the battery.

Under some circumstances, it is necessary to isolate the battery terminals to facilitate improved vehicle operation. For example, when the battery power is drained from misuse or overuse, it is necessary to shed one terminal from the normal electrical loads, saving that terminal for emergency starting only. In addition, when the voltage produced by the battery falls below a certain threshold, it is necessary to shed low current loads to prevent permanent battery damage. The shedding of low current electrical consumers protects the battery from long term irreversible damage occasionally caused by accidental deep discharge. Finally, the ultra low current electrical consumers should be permanently connected to the battery so that critical low current functions are maintained. The long lasting battery system of the present invention including a load shedding system is necessary to meet the needs of modem vehicles.

DTSCT,OSIIRE OF INVENTION

The automotive battery system of the present invention comprises a battery including at least two discharge characteristics, one capable of short high current discharge of electric power for cranking an internal combustion engine, and the other capable of providing a lower rate of current discharge as required for vehicle auxiliary power. The battery system of the present invention operates in combination with an integrated power switching system that provides protection to the battery system by synchronizing the battery's discharge rate with the electrochemical reactions of the battery system. Preferably, the battery system utilizes electromagnetic switches that open and close according to a pre-determined voltage and current level. The electromagnetic switches synchoronize the battery's discharge rate with the electrochemical reactions of the integrated battery. A preferred embodiment of the invention utilizes a binary battery of the type described in U.S. Application Serial No. 524,325, filed May 16, 1990, herein incorporated. Other battery configurations could be substituted without departing from the spirit or essential characteristics of the invention.

The binary battery disclosed by U.S. Application Serial No. 524,325, comprises a negative terminal grounded to the automobile, a first positive terminal connected to a series of cells which are capable of rapid discharge and recharge, as opposed to a second positive terminal connected to a series of cells which are capable of slower, deeper discharge and recharge. The two sets of cells are arranged in series parallel, thus providing dual or multi-current variations at the positive terminals. The series of cells connected to the first positive terminal have thinly layered positive plates providing high current for short durations. The cells connected to the second positive terminal have thickly layered positive plates providing lower current for longer durations.

The invention also consists of an automobile electrical power distribution system that, by measurement of the electromagnetic reactions of the integrated battery, is able to independently shed any loads across the integrated battery according to an optimized voltage or current that is synchronized with the electrochemical reactions of the battery. The invention further consists of an automotive electrical power distribution and switching system which includes a battery and an alternator, means for rectifying the alternating current provided by the alternator, and a means for regulating the voltage produced by the alternator. The voltage regulator preferably includes a Zener diode, a temperature sensitive resistor, and a transistor. Preferably, the voltage regulator is located within the battery in order to achieve a more accurate reading of the battery temperature. The voltage output of the alternator charging system is thereby more accurately synchronized with the electrochemical reactions of the battery based on the actual internal temperature and chemical conditions of the battery. In another embodiment of the present invention, the improved power distribution and switching system is integrated with a manual switching and signalling system and a series of sensor controllers and decoders attached to each of the electrical loads. The manual switching and signalling systems of the present invention accepts switch data from either the automobile itself or a user. The switch data indicates which loads require power and is fed by the switching and signalling system to a digital code generator. The binary code generator sends binary coded signals to a series of sensor controls and decoders. The decoders analyze the binary signals and transfer power to electrical consumer loads corresponding to the decoded binary signals. A power bus, separate from the binary signal line, delivers power to requesting users. The power bus is tapped off at suitable locations in order to provide power to electrical consumers with varying current requirements. Separating the binary signal line and switching system from the power bus reduces the size and weight of the electrical harness for a given number of electrical loads and functions. The present invention provides an optimized automotive power distribution and switching system that is totally integrated and synchronized with the electrochemical reactions of a preferred power supply battery. Together with a charging system, also integrated and synchronized to the electrochemical reactions of the preferred battery system, the invention provides a safe and reliable power distribution system. BRIEF DESCRIPTION OF DRAWINGS

Figure 1 is a simplified schematic of a typical automotive electrical power distribution system.

Figure 2 is a schematic diagram of a preferred power distribution and switching system of the present invention. Figure 3 is a graph illustrating the effect of removing loads from a typical SLI battery.

Figure 4 is a simplified schematic diagram illustrating another preferred embodiment of the power switching system of the present invention.

BEST MOPES FOR CARRYING OUT THE INVENTION

The present invention comprises a power distribution and switching system for an automobile that includes a binary battery system comprising a series of cells optimized for deep cycle discharge, and cells optimized for rapid shallow discharge. The distribution and switching system includes an alternator that is similar to the alternator used in conventional automobiles. The alternator includes an integrated rectifying circuit providing direct current to a voltage regulator that is remote to the alternator. An integral switching system comprises both electronic and electromagnetic switches that are used to synchronize the charging of the battery with the electrochemical conditions of the battery and the temperature variation in the remote voltage regulator.

Figure 1 illustrates a simplified schematic of a typical automotive power distribution system of the prior art which includes a conventional SLI battery 1, an alternator generator 2, an electromagnetic switch 3 used to connect the starter motor 4, the ignition system 5, the key switch (or ignition switch 6), and electric power consumer loads 7, 8, 9 and 10, such as lights, wipers, etc. The electric power consumer loads 7-10 can be switched on by switches 11, 12, 13 and 14. Switches 11-14 are positioned at either the negative or positive sides of the loads in series. Accessory load 15 can be operated only when the key switch 6 is moved to a predetermined position 60. Load 15 typically is a radio device which is powered on by switch 16. An additional accessory load 17 is similarly powered on when the key switch is moved to the same predetermined position 60. Load 18 may be an ultra low current load that is powered on by switch 22 according to a predetermined event, such as a remote electronic signal. Both loads 19 and 20 continuously consume ultra low current regardless of the position of the key switch 6. These ultra low current consumers may include clocks and memory devices. The ground connection 21 of the power distribution system is grounded to the vehicle body.

The conventional key switch 6 may be operated remotely by low current or an electronic signal; however, the functions are the same as outlined in the simplified mechanical illustration of Figure 1. As illustrated in Figure 1, a moving conductor 23 may rotate through positions 60-62 by the turn of the vehicle's key once it is inserted into the ignition lock. In the illustration, when the key is turned to the left into position 60, the conductor 23 first engages line 26 which switches current to the accessory loads 15 and 17, such as a radio or cigarette lighter. When the key is further turned to the left into position 61, the conductor 23 engages line 25 which conducts current to the ignition system 5 and engine management systems (not shown), or any other systems which consume power only while the engine is running. A further turn of the key to the left into position 62 engages the conductor 23 with line 24 which powers starter switch 3. The last turn position 62 of the key switch 6 requires that the key switch 6 be held against a bias away from position 62. If the key switch 6 is released, conductor 23 will spring back away from the contact of line 24. Line 27 provides the power from the vehicle's battery to conductor 23.

Turning now to Figure 2, a simplified schematic is shown illustrating a preferred embodiment of the automobile power distribution and switching system of the present invention, which includes a preferred binary battery 100 of the present invention. The binary battery 100, of the type described in U.S. Application Serial No. 524,325, filed May 16, 1990, herein incorporated, preferably includes a first terminal cell 137 that is a series of thickly layered positive plates that are optimized for deep cycle discharge. A second terminal cell 136 is a series of thinly layered positive plates that are optimized for rapid shallow discharge as is typical in conventional SLI batteries.

The binary battery 100 is grounded from a single negative terminal 138 to the vehicle chassis at terminal 121. A heavy current capacity line 139 is connected to terminal 136, which connects a starter switch 103 to terminal 136. When starter switch 103 is closed a starter motor 104 is activated. The starter motor 104 cranks the vehicle's internal combustion engine (not shown).

Preferably, the series of cells at terminal 136 which are optimized for high current discharge are able to provide at least 250 amps of discharge for a period of at least 30 seconds while under load at 18°C. In addition, the voltage at the terminal 136 must not drop below 6.5 volts during the 30-second period of discharge at 250 amps. Preferably, the voltage at terminal 136 starts at between 12.4 and 12.8 volts before the load is applied. The series of cells at terminal 137 that are optimized for slow, deep discharge preferably are able to provide one amp of current for a period in excess of 25 hours while under load at 25° C without the voltage dropping below 10.5 volts. The voltage at terminal 137 starts at between 12.2 and 12.6 volts before the load is applied. The overall capacity of the combined cells of the binary battery 100 based on a 20-hour discharge rate should be between 50 and 60 amp hours, down to a nominal voltage of 10.5 volts.

The present invention includes a switch 128 that, when activated, connects terminals 136 and 137 of the battery system together. Power to activate switch 128 is provided first from terminal 137 via line 135 and 141 from alternator 102. The alternator 102 includes a voltage regulator 129 which is remote from the alternator 102. The voltage regulator 129 is preferably placed on, into or within the battery 100, and is directly connected to the alternator 102. Preferably, the voltage regulator 129 is set inside the cover of the battery 100.

The voltage regulator 129 includes a Zener Diode 156 of a specified rating that allows voltage to pass above a minimum charging level, a temperature sensitive resistor 157 that

8 sets the passing voltage at a minimum level and a transistor 130 that controls the operation of switch 128. The preferred minimum charging voltage level that is able to pass through the Zener Diode 156 is selected to prevent deficit charging of the high discharge rate battery cells at terminal 136 when the alternator 102 is producing less than a predetermined minimum voltage. The minimum voltage is chosen such that the high discharge rate cells are not permanently damaged during charging. Preferably, the value of the temperature sensitive resistor 157 is chosen such that when the temperature of the .resister increases above a preferred threshold level, where the battery will no longer perform as designed, an above temperature warning will be delivered to the remainder of the voltage regulator circuitry 129 which prevents the charging of both cells of the battery 100.

More specifically, when the temperature increases above the preferred threshold level, the temperature sensitive resistor 157 causes the voltage delivered to transistor 130 to be below the minimum turn-on level for the transistor 130. This causes transistor 130 to turn "off' which causes switch 128 to open, thus preventing charging of both cells of the battery 100 at excessive temperatures.

By positioning the temperature sensitive resistor 157 inside the cover of the battery 100, the voltage regulator 129 is able to regulate the voltage output of the alternator 102 in reference to the actual temperature of the battery 100 rather than by using the temperature of the alternator 102 as in prior art battery systems. A more accurate reading of the battery temperature allows charging of the battery 100 by the alternator 102 to be closely synchronized with the actual electrochemical conditions of the battery 100.

The Zener diode 156 is provided to prevent. The Zener diode 156 prevents the voltage from the alternator 102 from passing to the transistor 130 unless it is above the specific characteristics of the diode. If the voltage is passed to the transistor 130 the transistor will turn "on" and enable the closing of switch 128. The closing of switch 128 connects battery terminals 136 and 137 together, thus connecting both terminals 136 and 137 to the alternator 102. By isolating terminal 136 from the main electrical system of the automobile, terminal 136 is prevented from discharging as the demands on the electrical system increase. Instead, the cells of terminal 136 are saved for emergency cranking of the starter 104, as described in more detail below.

For example, if the Zener diode 156 is specified at 12.5 volts, the transistor 130 will turn on when the alternator 102 is producing more than 12.5 volts. However, if the temperature of the battery 100 is above the specified threshold, the temperature sensitive resistor 157 will prevent the delivery of the alternator voltage to the transistor 130. If the alternator 102 is producing more than 12.5 volts, i.e., the vehicle engine is running, and the temperature of the battery 100 is below the given threshold, the transistor 130 turns "on," thereby activating switch 128. Switch 128 connects terminals 136 and 137 of the battery 100 together, and enables both portions of the battery 100 to be charged. Further, switch 128 automatically opens when excess temperatures are reached, as determined by the temperature sensitive resistor 157, protecting the battery from damage caused when the temperature shifts out of synchronization with the electrochemical requirements of the battery. In this manner, the battery 100 and alternator 102 supply a more reliable and energy efficient charging system than those of the prior art.

Turning to the operation of the remainder of the switching system of the present invention, the key switch 106 operates in the same manner as the conventional key switch 6 described above. Current is provided to the key switch 106 and conductor 123 from terminal 137 via lines 141, 142 and 127. When the key switch 106 is turned to the left one position, call the "auxiliary" position 160, the conductor 123 is connected to line 126. Line 126 is in turn connected to switch 132 which controls the connection of auxiliary loads 117 and 115 to the battery system 100. Application of auxiliary load 115 is further controlled by switch 116. Switch 132 is provided to protect the battery 100 from excessive drainage in the event that the conductor 123 is left in the "auxiliary" position when the engine is not running. The operation of switch 132 is described in more detail below.

When the key switch 106 is turned to the left to a second position, called the "ignition" position 161, the conductor 123 is connected to line 125. Line 125 connects the vehicle's ignition system to the battery system 100. All other loads which are relevant to ignition are connected to the battery 100 through line 125.

When the key switch 106 is turned to the left to a third position or "start" position 162, the conductor 123 is connected to line 124. The starter switch 103 is closed and current is provided to the starter 104. As before, the last turn position of the key switch 106 to the "start" position 162 requires that the key switch 106 be held against a bias away from position 162. If the key switch 106 is released, conductor 123 will spring back away from contact with line 124. When the key switch 106 is held in the "start" position 162, current flows through conductor 123 to lines 144 and 124. The current to line 124 closes switch 103, which enables the high level current from terminal 136 to flow to the starter 104 via high current line 139. The high level current from terminal 136 is required only when the starter 104 is being cranked.

10 In a preferred embodiment of the automobile switching system, when the engine is being started, i.e., key switch 106 is in the "start" position 162, connecting line 127 to line 144, the current along line 144 closes switch 128 by bypassing voltage regulator system 129; thus, switch 128 is activated at a lower voltage than the pre-set "engine running" voltage, i.e. 12.5 volts. Current along line 144 will continue during cranking and will energize the coil of switch 131, thereby latching switch 131 into the "on" position. Current is thereby provided to loads 107-110.

Switch 113 controls current to load 107, switch 114 controls current to load 108, switch 112 controls current to load 109, and switch 111 controls current to load 110. These loads are typical electrical consumer loads such as wipers, lights, etc. A resistor 154 is provided for protection of transistor 130 due to the wide voltage range that can be applied to turn transistor 130 on. In another embodiment, this step is bypassed to avoid closing switch 128 during engine cranking by eliminating the connection of resistor 154 to the base of transistor 130, and eliminating usage of these loads while the engine is starting.

After the engine is started, conductor 123 is moved away from the "start" position 162 to the "ignition" position 161, and no longer connects terminal 137 to line 124 via line 144. Diode 140 is provided to prevent current flow back along line 144 to line 124 and ultimately to switch 103 after conductor 123 has moved away from the "start" position 162. With the conductor 123 in the "ignition" position 161 the power to hold switch 131 in the "on" state is provided from terminal 137 via lines 141, 142 and 133. Therefore, switch 131 will remain closed until the voltage at terminal 137 falls to the specified "drop out" voltage.

The "drop out" voltage is determined by the resistance value of variable resistor 155 and the internal resistance of the coil of the electromagnetic switch 131. For a nominal 12 volt automobile electrical system, the preferred "drop out" voltage is ideally 10.5 volts. The effect of the voltage dropping below the "drop out" level at switch 131 is that all consumer loads connected to switch 131, i.e., loads 107, 108, 109 and 110, will be shed from terminal 137. Switch 132 is designed to open when the voltage at terminal 137 drops below the "drop out" voltage. Thus, the "auxiliary" loads 117 and 115 are shed when the voltage reaches the "drop out" voltage. Preferably, switches 131 and 132 utilize a coil of a specified resistance that gradually reduces the electromagnetic force of the switch in synchronization with the voltage at terminal 137 in order to prevent damage to the switches 131 and 132 caused by fast removal of electromagnetic force.

11 By opening switch 131 when the drop-out voltage is reached, the voltage at terminal 137 will immediately begin to climb from the drop out voltage, i.e., 10.5 volts, to a level very close to the nominal battery voltage, i.e., between 11.5 and 12 volts. The voltage climbs after the loads are removed because the natural electrochemical diffusion of the electrolyte from within the active material of the electrode plates is slower than current consumption. Therefore, when current consumption is terminated, the diffusion process continues, resulting in a build-up of electrons on the surface of the electrode plates, thereby increasing the voltage at the battery terminal 137. The graph in Figure 3 illustrates this phenomena. Typically, the increase in voltage at terminal 137 would cause the electromagnetic switches 131 and 132 to oscillate until the voltage at terminal 137 see-saws up and then gradually down to below the "cut in" voltage of the electromagnetic switches. The present invention avoids this phenomena by supplying current to hold switch 131 and 132 on only when the voltage supplied from terminal 137 is higher than the "drop out" voltage of the coil. Once the voltage decreases to the "drop out" level, switch 131 opens and current is removed from line 133. Therefore, both switches 131 and 132 remain open until the key switch 106 is again turned to the "start" position 162, which connects conductor 123 with the terminals of lines 124, 125, 126 and 144 and delivers current once against to line 133. Because voltage at terminal 137 begins to immediately climb, due to the opening of switches 131 and 132, the voltage at terminal 137 quickly reaches the electromagnetic cut-in voltage of switches 131 and 132, thereby closing the switches again during the starting operation. After the engine is started, switches 131 and 132 will be held closed.

In addition, the ultra low current loads 118, 119 and 120, such as clocks, memory devices and electronic signals, are connected to the battery terminal 137 via line 135, and therefore are always provided with power independent of key switch 106. The connection of the ultra low current load 118 is controlled by switch 122, and therefore is not always demanding current from terminal 137.

The effect of the preferred power distribution and switching system results in a number of desirable conditions that provide for optimized vehicle safety and reliability. The first advantage of the preferred power distribution and switching system is that the battery 100 is protected from long-term irreversible damage caused by accidental deep discharge, and is further protected by the synchronization of the electromechanical reactions of the battery with the consumer loads of the vehicle. Secondly, the important ultra low current consumers, such as the vehicle's electronic memory devices and the vehicle clock, are

12 protected from loss of power as they are permanently connected to the battery 100, and can therefore remain operating for long periods.

Thirdly, the preferred binary battery 100 can provide power from terminal 137 for emergency purposes without allowing the cells to drain. The user can therefore use recreational or emergency lighting without risk of either long-term battery damage or battery drain. Lastly, in the event that the power at terminal 136 is drained, the car is started in the normal way, by turning the key switch 106, because power is automatically provided to crank the engine from terminal 137. The operation of the power distribution and switching system of the present invention is therefore completely transparent to the vehicle user.

In addition, the preferred embodiment of the power distribution and switching system of the present invention provides for a more efficient use of the alternator and battery. The system of the present invention enables the battery to more rapidly recover from discharge. Switch 128 prevents discharge from terminal 136 to low current loads while the alternator is not operating. Recovery from discharge after cranking is therefore relatively fast and without voltage drop across switch 128, as would be the case if a diode was alternatively used. The cells of terminal 137, that are designed to shallow cycle, may be maintained at a state of charge on average 50% below the cells of terminal 136 due to the load shedding capability inherent to switches 131 and 132. Therefore, the electric energy available throughout the distribution network can be applied to more consumers without affecting the safety and reliability of the automobile.

The present invention provides for a synchronized power switching system that enables the additional of such devices as linear electric drivers to replace conventional hydraulic power steering systems of prior art automobiles. Indeed, linear electric drivers, or electric motor drives for power steering systems, facilitate safer driving than do the conventional systems because electric drivers, integrated with the system of Figure 2, continue to operate safely after engine failure. Similarly, power assisted electric brakes may also be integrated with the system of Figure 2, further adding to vehicle safety. An electric heat exchanger system may also replace the present mechanically driven compressor of air conditioning systems. Mechanically driven devices such as the compressor and hydraulic pump can be removed and replaced with a more efficient alternator that is integrated with the synchronized power switching and distribution and optimized battery system.

In another embodiment of the present invention, as illustrated in Figure 4, a simplified automotive power distribution and switching system includes a preferred binary battery

13 100 as described above. Further, a first positive terminal 236 of the battery 100 is connected to a series of high current discharge cells, also as previously described, and then to line 239, that connects to the vehicle's starter switch. A second positive terminal 237 of the preferred battery 100 is connected to a series of cells manufactured to specifications suitable for slow but long, shallow discharge and recharge cycles.

Preferably, the series of cells at terminal 236 which are optimized for high current discharge are able to provide at least 250 amps of discharge for a period of at least 30 seconds while under load at 18°C. In addition, the voltage at the terminal 236 must not drop below 6.5 volts during the 30-second period of discharge at 250 amps. Preferably, the voltage at terminal 236 starts up between 12.4 and 12.8 volts before the load is applied. The series of cells at terminal 237 that are optimized for slow, deep discharge, preferably are able to provide one amp of current for a period in excess of 25 hours while under load at 25°C without the voltage dropping below 10.5 volts. The voltage at terminal 237 starts at between 12.2 and 12.6 volts before the load is applied. The overall capacity of the combined cells of the binary battery 100 based on a 20-hour discharge rate should be between 50 and 60 amp hours, down to a nominal voltage of 10.5 volts.

In the embodiment of the present invention as illustrated in Figure 4, switch 228 (not shown) is provided first from terminal 237 via line 235 (not shown) and line 241 from alternator 202 (not shown). The alternator 202 includes a voltage regulator 229 (not shown) which is remote from the alternator 202 and which functions similarly to the voltage regulator 129 as described in reference to Figure 2. The voltage regulator 229 is preferably placed on, into, or within the battery 100 and is directly connected to the alternator 202.

The embodiment of the present invention illustrated in Figure 4 also includes load shedding switches similar to those described in Figure 2. For example, the embodiment illustrated in Figure 4 includes a transistor 230 (not shown) which operates similarly to transistor 130 as described in reference to Figure 2. This transistor causes switch 228

(not shown) to open which prevents charging of both cells of the battery 100 at excessive battery temperatures. In addition, the embodiment illustrated in Figure 4 similarly includes a key switch 206 (not shown) which is operated similarly to key switch 106 as described above. When key switch 206 is in the "start" position 262, switch 231 will be latched into the on position. Similar to switch 131, switch 231 will remain closed until the voltage at terminal 237 falls to the specified "drop out" voltage. The "drop out" voltage is determined by the resistance value of variable resistor 255 (not shown) and the internal resistance of the coil of the electromagnetic switch 231.

14 The remainder of the switching system of the embodiment illustrated in Figure 4 operates similarly to the switching system described above in connection with Figure 2. Current is provided to a key switch 206 (not shown) and conductor 223 (not shown) from terminal 237 via line 241, 242 and 227 (not shown). The key switch 206 is operated through an "auxiliary" position, a "start" position, and an "ignition" position, as described above with operation of key switch 106.

A first negative terminal 238 of the battery 100 is grounded to the body of the vehicle at 221. Loads 207, 208, 209, 210, and 215, are also grounded at 221. Power to all loads, except the very high current starter motor, is provided from terminal 237 via line 241 from the vehicle alternator and through line 242, which includes a main safety fuse 245. Terminal 237 is connected to loads 207-210 and load 215 when switch 231 is closed.

The switching of the power consumer loads as illustrated by Figure 4 is accomplished by an ultra-low current sensor signalling scheme. Sensor controllers and decoders, of a type well known in the art, are illustrated at 246, 247, 248, 249 and 250. Figure 4 is a simplified illustration of the ultra-low current sensor signalling scheme. Any number of sensor controllers and decoders may be incorporated into the distribution network. Although Figure 4 illustrates that the control sensors and decoders are positioned on the positive side of the loads, the devices may also be positioned on the negative side of the power consumer loads. A manual switching and signalling system 251 is powered from terminal 236 through line 252. All manual switching is represented by system 251. System 251 consists of a digital binary code generator, well known in the art, and each switch of system 251 sends a signal to each of the sensor controllers and decoders 246-250, when activated by the vehicle user. Of course, those of ordinary skill in the art will be familiar with binary code generators, decoders, controllers and equivalent devices. The decoders of the sensor controllers analyze the binary signals and switch power to the power consumer loads that correspond to the decoded binary signals. The signals transmitted from switching system 251 may be in the form of sound waves, direct current pulses sent along line 253, or infrared light pulses transmitted through air space or along a fiber optic line.

The power distribution and switching system of Figure 4 greatly reduces the weight and complexity of an automobile's electrical power distribution system. The power distribution and switching system of Figure 4 may be integrated with the system of Figure 2. For example, switching system 251 of Figure 4 may control the closure of

15 load switches 113, 114, 112, 111 and 110 of Figure 2. Using the load shedding and switching systems of Figure 2, in conjunction with the ultra-low current sensor signalling scheme of Figure 4, greatly enhances the safety, reliability and convenience of the automobile. The alternate embodiment illustrated in Figure 4, is advantageous over the prior art because it eliminates the need for the conventional "wire harness" of an automobile. The conventional wire harness evolved throughout a period of rapid changes in vehicle electrical power requirements. However, the conventional wire harness was restricted by the limitations of a conventional single current source battery system. Indeed, the electrical harness of conventional automobile design is, to a large extent, built around the limitations of a battery and alternator which are not synchronized in either function or performance. By utilizing the bus system line 242, power distribution circulates the automobile and is tapped off at suitable locations, providing power to electrical consumers of varying current requirements. The switching of power to the consumers, separate from the bus harness, provides for the low current switching system described.

The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.

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Claims

WHAT IS CLAIMED:

1. An electrical power distribution and switching system for a vehicle comprising: a first power source configured to provide rapid, high current discharge power to a first load; a second power source configured to provide slow, deep cycle discharge power to a second load; a first switch for electrically connecting the first power source to the second power source; and means, responsive to a first selected condition detected in the vehicle switching system, for placing the first switch in a first configuration which electrically separates the first power source from the second power source.

2. The electrical power distribution and switching system for a vehicle as defined in Claim 1, wherein the means for placing the first switch in a first configuration comprises an electrical circuit for detecting at least one of the selected conditions in the vehicle switching system.

3. The electrical power distribution and switching system for a vehicle as defined in Claim 1, wherein the first selected condition comprises a battery system temperature above a specified threshold.

4. The electrical power distribution and switching system for a vehicle as defined in Claim 1, wherein the first selected condition comprises an alternator voltage below a specified threshold.

5. The electrical power distribution and switching system for a vehicle as defined in Claim 1, further comprising: means, responsive to a second selected condition detected in the vehicle switching system, for placing the first switch in a second configuration which electrically connects the first power source to the second power source.

6. The electrical power distribution and switching system for a vehicle as defined in Claim 5, wherein the means for placing the first switch in a second configuration comprises an electrical circuit for detecting the second selected condition in the vehicle switching system.

17 7. The electrical power distribution and switching system for a vehicle as defined in Claim 5, wherein the second selected condition comprises a battery system temperature below a specified threshold.

8. The electrical power distribution and switching system for a vehicle as defined in Claim 5, wherein the second selected condition comprises an alternator voltage above a specified threshold.

9. The electrical power distribution and switching system for a vehicle as defined in Claim 5, wherein the second selected condition comprises positioning of a key switch in a starting position to electrically connect the first power source and second power source to a starter motor.

10. The electrical power distribution and switching system for a vehicle as defined in Claim 1, further comprising: a second switch for electrically connecting the second power source to the second load; and means, responsive to selected conditions detected in the vehicle switching system, for placing the second switch in a first configuration which electrically separates the second power source from the second load.

11. The electrical power distribution and switching system for a vehicle as defined in Claim 10, wherein the means for placing the second switch in a first configuration comprises an electrical circuit for detecting a third selected condition in the vehicle switching system.

12. The electrical power distribution and switching system for a vehicle as defined in Claim 10, wherein the third selected condition comprises a second power source voltage level below a specified threshold.

13. The electrical power distribution and switching system for a vehicle as defined in Claim 1, further comprising: a third switch for electrically connecting the second power source to the second load; and means, responsive to commands initiated by a vehicle user, for placing the third switch in a second configuration which electrically connects the second power source to the second load.

14. The electrical power distribution and switching system for a vehicle as defined in Claim 13, wherein the means for placing the third switch in a second configuration comprises:

18 a sensor for detecting an external stimulus provided by the vehicle user, a means for generating a control signal responsive to the external stimulus; a decoder electrically connected to the third switch; and a signalling bus electrically connected to the decoder for transmitting the control signal to the decoder.

15. A vehicle electric power distribution and switching system, including a battery system, comprising: means for measuring the electrochemical reactions of the battery system; means, responsive to the measuring means, for shedding loads from the battery system when the battery system produces a voltage below a specified level; means for providing an alternating current to charge the battery system; means for rectifying the alternating current; means for independently charging the positive terminals of the battery system based on the temperature of the battery system and based on the voltage associated with the rectified alternating current; and means responsive to an external stimulus for electrically connecting the first positive terminal to the second positive terminal during a time period defined by the presence of the external stimulus, so as to carry power from both the first and second positive terminals to an electrical load connected to the first positive terminal during said time period.

16. The vehicle electric power distribution and switching system defined in Claim 15, further comprising: means for regulating a voltage created by the alternating current producing means based on the temperature of the battery system, said voltage regulating means being positioned proximate to the battery system so as to achieve a more accurate reading of the battery system temperature.

17. The vehicle electric power distribution and switching system defined in Claim 15, further comprising:

19 means, responsive to commands initiated by a vehicle user, for electrically connecting a selected load to the battery system.

18. The vehicle electric power distribution and switching system defined in Claim 17, wherein the means for connecting the selected load comprises: means for detecting a vehicle user request that the selected load be connected to the battery system; means for generating a control signal in response to the detected user request; means associated with the load for decoding the control signal; means for distributing the control signal to the decoding means; means associated with the decoding means and responsive to the decoded control signal for electrically connecting the battery system to the selected load.

19. An electrical power distribution and switching system for a vehicle having an alternator and a plurality of electrical loads comprising: a battery system having at least two positive terminals, wherein a first positive terminal is connected to a series of cells optimized for rapid, high current discharge power, and wherein a second positive terminal is connected to a series of cells optimized for slow, deep cycle discharge power, at least one sensor for detecting selected conditions in the power distribution and switching system; a plurality of switches, positioned in the battery system so as to selectively, electrically connect the battery system to the loads, said switches being responsive to the detection of selected conditions in the power distribution and switching system, for controlling the connection of selected loads to the battery system and for controlling the charging of the battery system by the alternator in response to detection of said selected conditions.

20. The electrical power distribution and switching system for a vehicle as defined in Claim

19, further comprising a rectifier, and wherein the alternator provides an alternating current to charge the battery system and the alternator is connected to the rectifier for rectifying the alternating current provided by the alternator.

21. The electrical power distribution and switching system for a vehicle as defined in Claim

20, further comprising a voltage regulator for regulating the voltage associated with the alternating current

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22. The electrical power distribution and switching system for a vehicle as defined in Claim 21, wherein the voltage regulator is positioned proximate the battery system.

23. The electrical power distribution and switching system for a vehicle as defined in Claim 21, wherein the voltage regulator regulates the voltage provided by the alternator to the battery system based upon the temperature and chemical conditions of the battery system.

24. The electrical power distribution and switching system for a vehicle as defined in Claim 19, wherein the first positive terminal provides a high level current sufficient for supply of power to a conventional vehicle starter motor, during cranking of the motor when starting an associated engine.

25. The electrical power distribution and switching system for a vehicle as defined in Claim 19, wherein the second positive terminal provides a current sufficient for supply of power to conventional vehicle electronic auxiliary loads.

26. The electrical power distribution and switching system for a vehicle as defined in Claim 19, wherein at least one of the plurality of switches disables the charging of the first positive terminal of the battery system when the alternator produces a voltage below a specified level or when the temperature of the battery system is above a specified level.

27. The electrical power distribution and switching system for a vehicle as defined in Claim 19, wherein at least one of the plurality of switches enables the charging of both the positive terminals when the alternator is producing a voltage above a specified level and the temperature of the battery system is below a specified level.

28. The electrical power distribution and switching system for a vehicle as defined in Claim 19, wherein at least one of the plurality of switches enables the charging of the first positive terminal when the alternator is producing a voltage above a specified level.

29. The electrical power distribution and switching system for a vehicle as defined in Claim 19, wherein at least one of the plurality of switches electrically connects the second positive terminal to a starter motor of a conventional vehicle when the voltage of the battery system at the first positive terminal drops below a specified level.

30. The electrical power distribution and switching system for a vehicle as defined in Claim 21, wherein the voltage regulator further comprises a Zener diode and a temperature sensitive resistor.

31. The electrical power distribution and switching system for a vehicle as defined in Claim 19, wherein at least one of the plurality of switches electrically separates the loads from

21 the battery system when the voltage of the battery system at the second positive terminal drops below a specified level.

32. The electrical power distribution and switching system for a vehicle as defined in Claim 31, wherein the switch further comprises a conducting coil of specified resistance providing gradual reduction of electromagnetic force on the switch in synchronization with the voltage at the second positive terminal.

33. The electrical power distribution and switching system for a vehicle as defined in Claim 19, wherein at least one of the plurality of switches comprises a key switch capable of alternatively electrically connecting the positive terminals to at least one auxiliary load, an ignition system, and a starter motor of a conventional vehicle.

34. The electrical power distribution and switching system for a vehicle as defined in Claim 19, further comprising a plurality of low current loads permanently electrically connected to the second positive terminal.

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