CN117318205A

CN117318205A - Sequential discharge of storage batteries in a power supply system

Info

Publication number: CN117318205A
Application number: CN202310784780.2A
Authority: CN
Inventors: 陈拱辰
Original assignee: Power Transmission Technology Co
Current assignee: Power Transmission Technology Co
Priority date: 2022-06-29
Filing date: 2023-06-29
Publication date: 2023-12-29

Abstract

The present invention relates to sequential discharge of batteries in a power supply system. The battery pack of an electric vehicle is divided into a plurality of removable and replaceable batteries to mitigate challenges associated with battery charging in an electric vehicle. A set of control switches are linked in the control chain to control the orderly discharge of energy of the batteries disposed in the battery pack.

Description

Sequential discharge of storage batteries in a power supply system

Technical Field

The invention relates to sequential discharge control and protection of a group of energy storage devices in a power supply system.

Background

Electric Vehicles (EVs) have been put on hold. However, the limited power storage capacity of electric vehicles (i.e., their battery packs) limits the acceptance of electric vehicles. Although the battery pack of an electric car may be fully charged at home using a class 1 or class 2 ac charger, the range and route of the electric car still depend on the availability of public quick-charging stations for long distance travel.

One approach to solving this disadvantage is to build more public charging infrastructure for electric vehicles, such as the high voltage three stage dc quick charging station provided in many places by tesla. This is a huge investment. In addition, three-stage chargers are often incompatible between different electric vehicle manufacturers using proprietary technology.

Another solution being explored by electric automobile manufacturers is the use of battery pack exchange technology. Some electric vehicles, such as tesla Model-S, allow the entire battery pack in the electric vehicle to be replaced at a service station. When the energy of the replaceable battery pack is exhausted, the driver may drive the electric vehicle to a battery replacement facility where the robot lifts the entire electric vehicle, removes the entire battery pack under the vehicle, and replaces it with a fully charged battery pack. It is not cost-effective to build a battery pack exchange facility; furthermore, if there is energy in the battery pack but not enough to reach the destination, exchanging the battery pack is wasteful to the consumer and is not an efficient way of energy use.

An automobile using an internal combustion engine can be fueled with gasoline from different refineries at a convenient fueling station, regardless of the manufacturer of the automobile. However, electric vehicles of different manufacturers are often equipped with batteries of different capacities, different configurations, and even different charging connectors, making quick chargers incompatible between different electric vehicles. When the battery pack of an electric vehicle is low, the electric vehicle driver is often required to find a nearby quick charging station to provide service with a compatible charger. When the battery pack needs to be charged, it would be advantageous if the electric car battery could be charged as conveniently as the car would be refueled at a gas station without being limited by any particular quick-charge facility.

Disclosure of Invention

In an electric vehicle, a large number of battery cells are connected in series and/or parallel into a battery module. And then the battery module is assembled into a battery pack to provide a source of electric energy for the electric automobile.

The battery modules in the battery pack are configured to be easily removed and replaced so that the energy-depleted battery modules can be easily removed from the battery pack and replaced with fully charged battery modules. The method can solve the problem of insufficient battery capacity of the electric automobile. The replacement can be done by the driver himself or by a battery replacement service station. In one embodiment, a sequential discharge configuration is described in which a group of battery modules divided in a battery pack is controlled by an associated set of control switches such that energy in the battery modules is sequentially discharged for use by an electric vehicle. The electric vehicle driver can sense the energy usage of the battery modules in the battery pack, such as which battery module is in use, the number and location of battery modules that are depleted, and how much more energy is available to drive to the destination. If the electric vehicle does not have sufficient battery power to reach its destination, some depleted battery modules may be charged at a quick-charge station or may be replaced at a convenient battery service store that provides battery module replacement services, similar to fueling the vehicle at a fueling station. If the driver needs to drive to a remote area without battery service, the driver can carry several spare battery modules on the road for battery replacement. This may eliminate electric vehicle mileage anxiety for the electric vehicle owner or potential purchaser.

In one embodiment, a discharge control switch for facilitating sequential discharge of battery modules in a battery pack includes: comparing means for monitoring the energy level in the associated battery module; and a 1:2 demultiplexer for controlling the transmission of power from the associated battery module to the battery pack output through the transmission means if there is sufficient energy available at the associated battery module, and automatically switching to a subsequent battery module having sufficient available energy for output when the energy in the associated battery module is exhausted. A state buffer coupled to the output of the comparator may be used to indicate the energy state in the associated battery module. The discharge control switch is alternatively referred to herein as a "control switch". The control switch may be implemented using discrete electronics or as a chip (chiplet) in a multi-chip package. It may also be implemented using one or more integrated circuits.

The control switch has an "enable input", which is the "control output" of the previous control switch in the control chain, which is a serial link made up of a set of control switches. If the enable input of the control switch is active and if the energy in the associated battery module is sufficient for output, the control switch will activate its transmitting means to transmit power from the battery module to the output of the battery pack.

The series connection links a set of control switches in a chained configuration to automatically control the orderly discharge of a set of battery modules in the battery pack by connecting the control output of a previous control switch to the enable input of an active control switch and the control output of an active control switch to the enable input of a subsequent control switch. These connections form a sequential discharge control chain, which may also be referred to herein simply as a "control chain," i.e., the energy in a group of battery modules is sequentially discharged in a predetermined order according to the connection order in the control chain.

The linked configuration between the control switches forms a power priority chain. However, priority control is not a critical issue. From the point of view of energy discharge, all battery modules controlled by the control switch function equally. The power priority is mainly to control the orderly discharge of energy between a group of battery modules within a battery pack.

In one embodiment, when a key on the electric vehicle is turned on, the control signal is effective to activate a control switch coupled to a first battery module in the battery pack having sufficient energy for output. When the energy in the first battery module is depleted, the control switch will validate the control output according to the linked sequence of control switches in the control chain to activate the subsequent control switch, wherein the subsequent control switch is one control switch coupled to the battery module in the battery pack having sufficient energy for output.

If there is insufficient energy for output by any battery module between the first and subsequent battery modules, then those depleted battery modules will be skipped by the control chain. This is because the comparison means in the control switch associated with the energy depleted battery module will output a logic low to enable the control output to activate the next control switch in the control chain to check if the output of the comparison means in the next control switch is a logic high. This process will continue until a control switch is reached that detects sufficient energy in its associated battery module, and it will then activate its transmission means to power the battery pack. Such a discharge process will proceed in sequence until the energy of all the battery modules in the battery pack is exhausted. A depleted battery module means that the battery module shows a decay voltage below the reference level monitored by the comparison means in the associated control switch.

This makes the battery module replacement process very friendly, since any depleted or empty battery modules in the battery pack are automatically skipped by the control chain, without worrying about the replacement sequence, nor without replacing depleted battery modules in the battery pack during battery use.

A status output interface in the control switch indicates the power status of the coupled battery module. By detecting the status output, the electric vehicle driver can perceive how many battery modules still have sufficient energy for driving. If the remaining battery modules have sufficient energy for the entire trip, the driver may wait until the destination is reached before charging the depleted battery modules. Otherwise, some of the depleted battery modules may be replaced or replaced with fully charged battery modules at the service station or charged at a quick charging station.

The comparison means in the control switch may be a comparator consisting of an operational amplifier outputting a logic high level or being saturated in an active state when its input voltage is higher than the reference voltage and outputting a logic low level or being saturated in an inactive state when its input voltage is lower than the reference voltage.

In one embodiment, the comparing means may consist of an analog-to-digital converter (ADC) the output of which is connected to a magnitude comparator for comparison with a reference value reflecting the minimum voltage requirement of the battery module to generate an output signal similar to the output of the comparator for controlling the power switching between the control switches. The comparison output is valid when the output of the ADC is higher than the reference value in the size comparator. The reference value may be a hard-wired value in the control switch or a value stored in ROM, EPROM or EEPROM. The ADC output may also be coupled through an I/O interface port (e.g., I ² C or Controller Area Network (CAN) interface) instead of observing through a single status bit in the status port, thereby providing a higher resolution for observing the available energy in the battery module.

In one embodiment, a protection device may be incorporated between the battery module and its associated control switch to prevent unnecessary leakage of power when the electric vehicle power is turned off and to prevent false excessive depletion of the battery module depleted during the power on of the electric vehicle, thereby reducing battery life. The protection device may include two protection switches in series, one of which is a key-on switch (key-on switch), which is normally open by default and which is closed when the electric vehicle is powered on. Another protection switch, a combination switch (conjunction switch), is normally closed by default and opens when the energy of the associated battery module is exhausted. The two series switches may be connected in any order. They may be combined into a single switch, a battery protection switch, which is controlled by an equivalent implementation of the two protection switches described above.

It is desirable to achieve standardization in the physical configuration and power capacity of the battery modules. It makes battery module interchangeable between different electric vehicles. The power capacity of a battery module may be standardized to one or more specific dimensions, where a power consuming electric vehicle may use a larger capacity battery module, while a typical or smaller electric vehicle may use a conventional capacity battery module.

In one embodiment, the battery module and associated control switch may be configured to increase the output voltage and/or output current of the battery pack. This may be accomplished by rearranging a plurality of battery modules in a battery pack into a plurality of subgroups, then connecting the battery modules in each subgroup in series to increase the output voltage, and then connecting a control switch to the subgroup of battery modules to activate the increased voltage output. Likewise, the output current of the battery pack may also be increased by activating a subset of the control switches in the discharge control chain to activate a subset of the battery modules in the battery pack associated therewith while outputting current.

To activate a subset of battery modules while outputting power, the enable control inputs of a subset of control switches associated with the subset of battery modules may be connected together such that all control switches in the subset receive the same enable input signal. Furthermore, the control outputs of all control switches in a control switch subset will be ored together externally as a new enable input signal to enable a subsequent control switch subset to activate its associated battery module in the battery pack while outputting current. The same control switch design applies to normal voltage and current outputs and to boosted voltage and current outputs.

In a discharge configuration, it is also possible for the battery pack to have both a higher voltage and a higher current output. This can be achieved by: the battery modules in the battery pack are rearranged into a plurality of battery module subgroups, and the battery modules in each subgroup are connected in series in advance, and then the control switches in the control chain are rearranged into a plurality of control switch subgroups, wherein the control switches in each control switch subgroup are coupled to the battery module subgroup. The same enable input will be input into a subset of the control switches. By having the same enable input signal active for all control switches in the control switch subgroup, all respective battery module subgroups associated with the control switch subgroup will output current while boosting the voltage. Similarly, the control outputs of all control switches in each control switch subset will be ored together externally to become a new enable input to enable the subsequent control switch subset in the discharge control chain. By simply increasing the number of battery modules connected in series in the battery sub-groups and increasing the number of battery sub-groups to output current at the same time to boost the output current, a higher output voltage and a higher output current can be achieved.

Drawings

Fig. 1 illustrates an exemplary battery module discharge configuration with a control switch according to one embodiment of the present invention.

Fig. 2A illustrates a protection device according to one embodiment of the present invention, which is adapted to prevent false energy discharge and deep energy exhaustion generated due to degradation of a battery module.

Fig. 2B illustrates a protection device for a battery module according to an embodiment of the present invention.

Fig. 3 shows a battery module discharge control switch according to an embodiment of the present invention in which back-to-back PMOS-FETs are used as a transmission means.

FIG. 4A illustrates a logical representation of a 1:2 demultiplexer according to one embodiment of the invention.

FIG. 4B illustrates the use of a 1:2 demultiplexer in a discharge control switch according to one embodiment of the present invention.

Fig. 5A shows a control switch according to an embodiment of the invention in which back-to-back NMOS-FETs are used as the transmission means.

Fig. 5B shows a control switch according to one embodiment of the invention, which uses an ADC to compose a comparison device.

Fig. 6 shows a discharge control configuration according to an embodiment of the present invention, which has two battery modules connected in series to double the output voltage of a battery pack.

Fig. 7 shows a discharge control configuration according to an embodiment of the present invention, which doubles the output current of the battery pack by activating two control switches simultaneously.

Detailed Description

Mileage anxiety prevents consumers from purchasing electric vehicles. The slow charging of the primary or secondary battery further reduces the power of the electric vehicle. For example, a class 1 electric vehicle charger is plugged into a 120V AC outlet, and the highest output power on a 20A outlet may be 2.4KW. Taking tesla Model S as an example, an electric car with a battery capacity of 85 kwh, a class 1 charger requires more than one day to charge its battery. If the battery is plugged into an AC outlet at 240v 40a, it is charged with a secondary charger, with a maximum power of about 9.6KW, 4 times faster than the primary charger, but the Model S battery pack still requires one night to fully charge.

A more efficient charging scheme is to use a three-level fast charger, such as a tesla three-level fast charger, which can charge a depleted battery pack to 80% full capacity in about 30 minutes. However, tesla class 3 chargers cannot be used in every public place, nor are they compatible with electric car chargers of other car manufacturers. The proprietary rapid charging scheme is an obstacle for many electric car drivers on the road.

Battery module power sequential discharge control configuration

Herein, the term "battery module" refers to a battery. Thus, the terms "battery module" and "battery" are used interchangeably herein.

An embodiment for solving the anxiety of the battery of the electric vehicle is described in detail below. One embodiment is to divide a battery pack in an electric vehicle into a plurality of detachable battery modules (i.e., batteries) that can be easily removed and replaced by a driver or a service shop. A set of removable battery modules in the battery pack is then placed under control of a set of associated control switches to form a discharge configuration to power the electric vehicle use one at a time in turn until the energy in the entire battery pack is exhausted. The energy state of the battery modules of the electric automobile is observable, and a driver can easily perceive whether the number of the fully charged battery modules is sufficient for traveling. If there is a shortage of power, the driver may stop charging at the service shop or replace some of the depleted battery modules with fully charged battery modules to continue traveling until the destination is reached, where all of the depleted battery modules may be recharged using a primary or secondary charger. This is similar to fueling a car, and when the gas volume of the car becomes low, the driver can measure the state of the gasoline at any one of the gas stations to fueling.

The number of battery modules installed in an electric vehicle will depend on the characteristics of the electric vehicle or the driving needs. Smaller electric vehicles may install fewer battery modules in a battery pack. Large electric vehicles or electric vehicles requiring more power may be equipped with more battery modules or mounted with battery modules having higher energy capacity. For shorter commute times, fewer battery modules may be sufficient for use in an electric vehicle. If it is desired to travel to a remote location without battery replacement service, the battery backup module may be carried on the road for replacement. A potential electric vehicle purchaser may initially purchase only a few battery modules to reduce the cost of ownership of the electric vehicle and then add or rent more battery modules to fill the battery module backup slots, e.g., during long trips, depending on the use needs.

The battery modules may be designed with universal energy capacity in a standard form factor such that the battery modules are compatible and interchangeable between different electric vehicles. Then, the quick charge of the electric car battery will not be to charge the electric car battery at the three-stage charging station while on the road anymore, but will become to perform the battery module replacement service at the battery service station or store where the battery module is provided. The battery replacement can be done by the electric car driver self-service, just as self-service refueling at a gas station.

Fig. 1 illustrates an exemplary battery module power sequential discharge configuration 100 in which a battery pack 001 is divided into a plurality of removable battery modules 101, 102, …, 109, which are controlled by a set of control switches 110, 120, …,190, respectively, in accordance with an embodiment of the present invention. When the key of the key switch 005 is pressed to ON, the control signal BEN1 is effectively an enable input of the first control switch 110. While the battery pack 001 is shown as including four battery modules, it is understood that the battery pack may have more modules.

In fig. 1, the portion of the control switch 110 coupled to the battery module 101 includes a comparison device, shown as a comparator 111, for comparing the attenuated input to a reference voltage Vref. The attenuated inputs may be derived from voltage dividers R1 and R2, with voltage dividers R1 and R2 coupled to the output of battery module 101. The reference voltage Vref may be an external input voltage or an internal voltage set in the control switch 110. If comparator 111 detects that the decay voltage Vatt1 is higher than Vref, which means there is sufficient energy in battery module 101, then when the second input signal (i.e., signal BEN 1) to enable-AND gate 112 is also active, a logic high will be output to enable AND 112. In addition, if Vref is an external input, a common Vref may be set to the common input for all battery modules in the battery pack.

Assertion of enable-AND 112 (enable-AND 112) will activate transmission device 113 in control switch 110 to transmit voltage input VIN1 to VOUT1, with voltage input VIN1 being received from battery module 101 by switches 011, 021, AND signal Vatt1 being derived therefrom. The transmission device 113 may be an NMOS Field Effect Transistor (FET), PMOS-FET, a pair of back-to-back NMOS-FETs, a pair of back-to-back PMOS FETs, bipolar junction transistor, solid State Relay (SSR), electromagnetic relay, or the like.

The output buffer 116 receiving the signal from the output of the comparator 111 and provided in the control switch 110 may be coupled to an external display device or an LED 117 as shown in fig. 1. When the output of comparator 111 goes high, LED 117 lights up, indicating that battery module 101 has sufficient energy.

When the energy in the battery module 101 is exhausted, the output signal C1 of the comparator 111 switches to logic low. The signal C1 is inverted by the inverter 114 AND applied to a first input of the link-AND 115, wherein a second input of the link-AND 115 receives a further control input signal BEN1. When both input signals of the link-AND 115 are at a logic high level, the output of the link-AND 115 goes high, thereby asserting the control signal BEN2, which in turn is configured to activate the subsequent control switch 120 in the sequential discharge chain 100 for power output. The control switches 110, 120, 130, … and 190 operate in the same manner. For example, the voltage output by the battery module 102 received through the switches 012 and 022 is attenuated by the resistors R3 and R4 to generate a voltage Vatt2, which is applied to the comparator 121 provided in the control switch 120 associated with the battery module 102. If the decay voltage Vatt2 is higher than Vref, signal C2 will be at logic high AND enable-AND gate 122 will activate the transmitting means 123 in control switch 120 to transmit VIN2 from battery module 102 to voltage VOUT2. Likewise, when the energy in the battery module 102 is below a predetermined level, signal C2 will enable signal BEN3 via link-AND 125 to activate the next control switch 130 for power output. The same operation also occurs in the control switches 130, … and 190.

The link-AND gates 115, 125, …, 195 may be connected in series to form a link-AND chain. The link-AND chain control in the power sequential discharge control configuration 100 controls the sequential activation of the switches 110, 120, …, 190, which in turn controls the sequential discharge of power in the battery modules 101, 102, …, 109. When the power discharge control chain 100 is turned on, sequential activation occurs automatically without intervention of an external microcontroller.

Sequential activation under the control of the link-AND chain may skip any depleted battery modules in battery pack 001. This is because the comparison means provided in the associated control switch outputs a logic low when the energy in its battery module is exhausted. This will result in a logic high output at the link-AND of the associated control switch AND in turn will enable the enable input signal to activate its next control switch. Thus, the depleted battery module is skipped for energy output. When a defective battery module or a removed or uninstalled battery module is detected, the link-AND gate at the control switch in the control chain associated with the defective battery module (or even the removed battery module) operates in the same manner. In other words, all control switches coupled with depleted, defective or empty battery modules in the battery pack will be skipped during power output under control of the power sequential discharge control configuration 100 (i.e., the discharge control chain).

Thus, the electric car driver can replace the battery module at any depleted position at will, or can replace only a few depleted battery modules, and delay the charging of the entire battery pack until the destination (e.g., home) is reached. When a fully charged battery module is recharged or reinstalled in the battery pack 001, the link-AND chain will activate the first control switch in the discharge chain 100, which discharge chain 100 has sufficient energy for output when the chain is on. According to an embodiment of the invention, if the electric vehicle driver chooses to do so, only partially depleted battery modules are replaced, similar to partial fueling at a fueling station.

A local power source 199, such as a rechargeable battery, may be incorporated into the discharge control chain 100 to provide a local power source V for the control circuitry _{Logic for logic control} (V _LOGIC ). The V is _LOGIC Or can be derived internally within the control switch.

Anti-creeping for battery module in battery pack

Switches 011 and 021 are connected in series between the battery module 101 and its associated control switch 110 to mitigate deterioration of battery life. Likewise, switches 012, 022, etc. may also be incorporated between the battery module 102 and its associated control switch 120.

The default state of the switches 011, 012, …, 019 (i.e., push-to-talk switches) (constituting the switch group 133) is normally open. When the key of the key switch 005 is pressed ON, the control signal BEN1 is active to start the first control switch 110 to operate. The signal BEN1 also turns off all the key switches 011, 012, …, 019 in the switch group 133 in the discharge control chain 100. When the electric vehicle is not in use, the normally open switches 011, 012, …, 019 prevent the battery modules 101, 102, …, 109 from leaking electricity.

The other set of switches 021, 022, …, 029 (i.e. the combination switch) constitutes a switch set 134, which functions differently. The default state of the combination switches 021, 022, …, 029 in the switch group 134 is a normally closed state. When the key of the push switch 005 is pressed ON, both the push switches 011, 012, … 019 and the combination switches 021, 022, …, 029 are closed, so that the energy in the battery modules 101, 102, …, 109 of the battery pack 001 will be detected or received by the comparing means 111, 121, …, 191 to be observed at the output buffers 116, 126, …, 129 in the respective control switches 110, 120, …, 190.

The outputs of the status buffers 116, 126, …, 129 may be connected to an external display device, such as an LCD panel or LEDs 117, 127, … 197 as shown in fig. 1. Accordingly, the electric automobile driver can observe the energy state of the entire battery pack 001 when the electric automobile key switch 005 is pressed to ON.

The default state of the combination switches 021, 022, …, 029 in the discharge control chain 100 is normally off so that power is transferred. When the control switch 110 detects a depletion of energy in the battery module 101, the link-AND 115 in the control switch 110 will go high to assert the control output signal BEN2 to activate the subsequent control switch 120. Meanwhile, the signal BEN2 is also asserted to turn on the combination switch 021 to disconnect the battery module 101 from the power supply system of the electric vehicle, so as to prevent further false exhaustion of the energy of the battery module 101, such as leakage current through the voltage dividers R1 and R2.

Similarly, when the energy in the associated battery module 102 is exhausted, the control switch 120 will assert BEN3 the control output signal to activate the subsequent control switch 130 and open the combination switch 022 to disconnect the battery module 102 from the power system. This process will continue to open all normally closed combination switches to protect all depleted battery modules in the entire battery pack 001 under the control of the sequential discharge control chain 100.

The pair of switches coupling the battery module to the associated control switch constitutes a protection device. For example, switches 011 and 021 form a first pair of protection devices for battery module 101, switches 012 and 022 form a second pair of protection devices for battery module 102, and so on. Fig. 2A illustrates an embodiment of a protection device 200 that prevents false battery discharge when the electric vehicle is not in use and further prevents deep energy depletion from causing battery module degradation when the energy in the battery is depleted during power-up of the electric vehicle. The protection device 200 corresponds to protection devices 011 and 021 in the discharge control chain 100; 012 and 022;013 and 023, etc.

In fig. 2A, the push-to-talk switch 220 is normally open and closed if the key is pressed ON. The default state of the combination switch 230 is normally closed, which enables power in the battery module 210 to pass to the control switch, but the combination switch 230 becomes open when the signal NXEN (i.e., the control output signal) to activate the subsequent control switch is active. The signal NXEN corresponds to any one of the signals BEN2, BEN3, BEN4, …, BEN9 in the discharge control chain 100 in fig. 1. The opened combination switch 230 disconnects the output path of the battery module 210 from its control switch. This occurs when the energy in the battery module 210 is below a minimum voltage level.

Fig. 2B shows an alternative embodiment of a battery module protection device according to another embodiment of the present invention. In the protection device 250, instead, a normally open switch 270, i.e., a battery protection switch, is used. In the battery protection switch 270, the key input and the inverted NXEN input are and-operated as inputs to the switch 270. When NXEN is deactivated And the key input is ON, the output of nd 265 will go high to close normally open battery protection switch 270 to cause the energy in battery module 260 to be output to the associated control switch. When NXEN is active or when the key is OFF, battery protection switch 270 will open, i.e., return to its default state, to disconnect battery module 260 from its associated control switch to conserve battery energy. The push-to-talk switch 220 of fig. 2A, the combination switch 230 of fig. 2A, and the battery protection switch 270 of fig. 2B may be an electromechanical relay (EMR), a Solid State Relay (SSR), or any other electrically controlled switch in a MOSFET or bipolar transistor.

Referring to fig. 1, if the signal key at the key switch 005 in the discharge control chain 100 is OFF, the control signal BEN1 will be disabled. Failure of the BEN1 signal will cause all of the push switches 011, 012, …, 019 in fig. 1 to reset to their default state to open. Failure of the BEN1 signal also fails all consecutive BEN2, BEN3, …, BEN9 signals in the discharge control chain 100, such that the set of combination switches 021, 022, …, 029 are closed regardless of any one of the switches being open due to energy depletion in its previous battery module.

Accordingly, as the key at the push-to-talk switch 005 is pressed OFF, the connection between the battery module and its associated control switch will be restored to its default state to become open. Then, when the key is pressed ON, the battery modules in the battery pack 001 will be reconnected to their respective control switches to reveal the energy status of the entire battery pack, output energy from the battery modules in a predetermined order if the energy is available, and disconnect the battery modules from their respective control switches if the energy in the battery modules is exhausted under the control of the discharge control chain 100 with the protection device in place.

Control switch for battery energy discharge control

Fig. 3 illustrates an exemplary discharge control switch 300 for controlling the power output of a battery module according to an embodiment of the present invention. Fig. 3 also shows more details of the transfer device 350, such as the transfer devices 113, 123, 133, …, 193 in fig. 1. The discharge control switch 300 corresponds to any one of the discharge control switches 110, 120, 130, …, 190 in fig. 1. Transmission 350 shows a pair of back-to-back PMOS-FETs 317 and 318 operating as a power transmission. In one embodiment, the discharge control switch 300 includes, in part, a comparison device, shown here as a comparator 311, to compare the voltage input ATTVIN to a reference voltage Vref, where ATTVIN is the decaying voltage of VIN from the voltage dividers R1, R2, VIN being the energy output of the battery module coupled to the control switch 300. Vref may be an internal set voltage or may be connected to an external input Vref.

When the control input EN of the control switch 300 is active AND when the output of the comparator 311 is logic high, which means that there is sufficient energy in its associated battery module, then the enable-AND 312 will also be a logic high signal to enable the transmitting means PMOS-FETs 317, 318 to transmit power from terminal VIN to terminal VOUT. It is advantageous to use a pair of MOS-FETs as power transfer means. When the output voltage VIN of the associated battery module is lower than VOUT, the drain-source body diode of PMOS-FET 317 blocks the reverse current from VOUT to VIN. If the fully charged battery module controlled by control switch 300 is not ready to output power, the drain-source body diode of PMOS-FET 318 will block leakage current from VIN to VOUT.

The resistor R3 and the NMOS-FET 313 form an inverter in resistor-transistor logic (RTL). The RTL pull-up voltage for the inverter formed by R3 and NMOS-FET 313 is provided by VIN through the body diode of PMOS-FET 317 as a source. Inverter functionality is required for the pair of active low PMOS-FETs 317 and 318, but is not required if an active high NMOS-FET is selected in the control switch as the power transfer device.

If the output of comparator 311 goes low, which means that the energy in the associated battery module is falling or depleted AND there is no longer sufficient energy, then the inverted output of comparator 311 through inverter 314 will go to logic high (high), resulting in the output of link-AND 315 also being high, if EN is also active. A high at the output of link-AND 315 will cause the control output NXEN to be active, activating the subsequent control switches in the discharge control chain. Taking fig. 1 as an example, if the battery module 102 has sufficient energy for output, the control switch 120 is considered to be a subsequent control switch to the control switch 110. Otherwise, if the battery module 103 has sufficient energy for output, the control switch 130 is considered to be a subsequent control switch to the control switch 110, and so on.

The buffer 316 delivers an output of the comparator 321 for external observation of the battery status terminal to indicate the energy status of the battery module coupled to the control switch 300. The enable-AND 312, inverter 324, AND link-AND 315 form a 1:2 demultiplexer 320 in control switch 300, with the output of comparator 311 being a demultiplexer select control signal 321 to select EN as the demultiplexer input between the two demultiplexer outputs (i.e., enable-AND 312 AND link-AND 315). The control switch may be an integrated circuit. It may be implemented using discrete electronic devices, or as a set of chiplets in a multi-chip package (MCP).

Fig. 4A shows a logical representation of a 1:2 demultiplexer 400, wherein if the demultiplexer's selection control signal CNTL is 0, the demultiplexer input IN will be forwarded to the demultiplexer output OUT0. If the demultiplexer select control signal CNTL is 1, the demultiplexer input IN will be forwarded to the demultiplexer output OUT1.

Thus, FIG. 4B shows that the link-AND 315, the enable-AND 312, AND the inverter 314 in the control switch 300 of FIG. 3 form a 1:2 demultiplexer 320, where the enable input EN is the demultiplexer input signal AND the output of the comparator 311 is the demultiplexer select control signal 321. If the enable input EN (demultiplexer input) is active AND if the comparator output (demultiplexer select control terminal) is high, the enable-AND 312 will pass the signal EN, AND when active, activate the transmission means provided in the control switch to output the power of its associated battery module to the output of the control switch, which in turn is output to the output of the battery pack.

Conversely, if the enable input EN is active but the comparator output is low, link-AND 315 will have the signal NXEN active at its output to activate the subsequent control switch for power output in the discharge chain. However, when the enable input EN is disabled, both outputs of the 1:2 demultiplexer will be disabled and the control switch 300 will become inactive in the discharge control chain.

Fig. 5A illustrates another exemplary discharge control switch 500 for controlling the power output of a battery module according to an embodiment of the present disclosure. The discharge control switch 500 corresponds to the discharge control switches 110, 120, 130, …, and 190 as shown in fig. 1, wherein the back-to-back NMOS-FETs 517 and 518 form a transmission device, which corresponds to any one of the transmission devices 113, 123, 133, …, and 193. The comparison means in the control switch 500 may be a comparator 511 consisting of an operational amplifier, which comparator 511 outputs a logic high level or is saturated in an active state when its input voltage VINATT is higher than the reference voltage Vref, and outputs a logic low level or is saturated in an inactive state when its input is lower than the reference voltage Vref. VINATT is a decaying voltage derived from the voltage output of the battery module associated with control switch 500. Vref may be an internal voltage or an external input Vref. If Vref is an external input, VREF for all control switches may be connected to and controlled by the same reference voltage to ensure that the energy in all battery modules is depleted or reduced to the same low level.

Some aspects of the embodiment shown in fig. 5A include means to prevent abnormal damage to the control switch 500. For example, to prevent faults due to high voltage surges, the control switch 500 is adapted to include an Over Voltage Lockout (OVLO) circuit, which in part includes a comparator 512 to lock the control switch 500 when the input voltage exceeds a predefined limit. The electrical transient surge voltage can cause avalanche breakdown in the solid state device, which can damage the control switch. The overvoltage comparator 512 compares Vref with the decay voltage input OVLO. The voltage OVLO is lower than VINATT due to the addition of resistor R3 between the terminal of resistor R2 and ground.

During normal operation, the voltage OVLO is below Vref AND the output of comparator 512 is at logic high, thus having no effect on the output of AND gate 513. However, if during a power surge the voltage OVLO becomes higher than Vref, the output of the over-voltage comparator 512 will go low, resulting in the output of the AND gate 513 going low, AND gate 513 being the select control terminal of a 1:2 demultiplexer consisting of AND gate 515, AND gate 522 AND inverter 521 as shown in fig. 4B above. A logic low at the select control terminal of the demultiplexer will disable the power transfer means in the control switch 500 and enable the subsequent control switches in the discharge control chain for power output. If OVLO is higher than Vref, the pass device formed by NMOS-FETs 517, 518 in control switch 500 will be over-voltage locked.

An additional protection mechanism for the control switch 500, such as a slew rate control 523, or all or part of the current sensing device 514 or temperature sensor, may be included in the control switch 500, wherein the slew rate control 523 is used to smooth voltage spikes from VIN when the battery module is initially on; the current sensing means 514 is used to monitor and ensure that the current entering the control switch 500 does not exceed a predefined limit; the temperature sensor senses the junction temperature at the transfer device to protect the transfer device from overheating. When the detected abnormality signal is valid low, the output of the abnormality detection device may be input to the AND 513; when the detected abnormality signal is active high, the output of the abnormality detection device may be input to the NOR 519, disabling the comparator 511 output at AND 513 in fig. 5A. The output of AND 513 is a control signal input to the demultiplexer select control terminal. An inactive (de-asserted) demultiplexer select control signal will activate the subsequent control switches in the discharge control chain.

A pair of active high NMOS-FETs 517 and 518 in control switch 500 are connected to the output of charge pump 520 to boost the gate voltage to a level higher than the source voltage to enhance the channel conduction of the NMOS FETs. The body diodes in NMOS-FETs 517 and 518 block reverse current when voltage VOUT is higher than Vin and provide forward leakage protection when the fully charged battery module has not been activated for power output. Resistor R4, together with NMOS-FET 527 and inverter 526, forms an open-drain state buffer 525 in which the output of comparator 511 is observable at output BSTA, thereby developing the energy state of the associated battery module controlling switch 500.

Other embodiments of control switch designs within the scope of the present disclosure include the control switch design shown in fig. 5B, wherein the comparison means may consist of an analog-to-digital converter (ADC) 535, the output of ADC 535 being connected to a magnitude comparator 536 to compare with a reference value CMPVAL, reflecting the minimum voltage requirement in the associated battery module to generate a comparison output signal as an input to AND gate 560; which is similar to the output of comparator 511 input to AND gate 513 in fig. 5A. The comparison output of the magnitude comparator 536 becomes the selection control signal for the 1:2 demultiplexer in FIG. 5B to control the power switching in the control switch 550. The size comparator 536 may be a discrete device or may be implemented as a Programmable Logic Device (PLD) or the like.

In addition, the status buffer 525 (including the inverter 526 and the NMOS-FET 527) and the status bit BSTA in the control switch 500 in FIG. 5A may be replaced with an I/O interface unit 537 and a multi-bit I/O status port. Which is connected to an external I/O interface, such as the two-bit I at the status port in FIG. 5B ² A C interface or a Controller Area Network (CAN) interface. If the ADC output is accessible from the I/O interface unit 537, a higher resolution of the energy state in the battery module can be observed on an external display device (e.g., LCD panel). Digital CMPVAL reflecting the minimum voltage requirements in size comparator 536 may be hardwired or embedded in control switch 550 or programmed into a memory device, such as electrically erasable programmable only accessible through I/O interface unit 537 and an I/O status port Read memory (EEPROM).

In summary, the control switch includes: an input port for receiving an enable input signal; a control output port for asserting a control output signal; a power input port; a power output port; a power transfer device adapted to transfer input power received from the power input port to the power output port when the power transfer device is activated; and comparing means adapted to compare the external voltage with a reference voltage to generate a comparison output.

The control switch further comprises a switching control comprising 1:2 demultiplexing logic having a demultiplexing input coupled to the enable input signal and a demultiplexing select control signal coupled to the compare output, wherein the demultiplexing input (i.e., the enable input signal) is forwarded by the 1:2 demultiplexing logic to the first demultiplexing output port when the enable input signal is active to activate a power transfer means adapted to transfer power received from the battery module associated with the control switch to the power output port at the power input port when the compare output or the demultiplexing select signal is active; in addition, the demultiplexed input is forwarded by the 1:2 demultiplexing logic to the second demultiplexed output port to enable the control output signal, which can be input to the enable input port as a demultiplexed input of a subsequent control switch when the demultiplexed select signal is not enabled (de-asserted).

In addition, the control output port of the control switch may be linked to the enable input port of a subsequent control switch, thereby forming a link-control chain to control automatic power switching of the associated battery module in the battery power supply system.

When the demultiplexed selection signal changes state, the incorporation of demultiplexing logic in the control switch may switch simultaneously between the control switch and the subsequent control switch, and thus between the associated battery module and the subsequent associated battery module, thereby minimizing transient noise and glitches during power switching.

Increasing output voltage and current at a battery pack

In one embodiment, the battery module and associated control switch may be configured to increase the output voltage and/or output current at the battery pack. This can be achieved by: the plurality of battery modules in the battery pack are rearranged into a plurality of subgroups, and then the battery modules in each subgroup are connected in series to output a boosted voltage from the control switch before being input to the control switch associated with the subgroup of battery modules. Also, the output current of the battery pack may be increased by activating a control switch subset in the discharge control chain to activate an associated battery module subset in the battery pack to output power at the same time.

Fig. 6 shows an exemplary discharge control configuration 601 comprising four battery modules 610, 620, 630 and 640, wherein battery modules 610 and 620 are connected in series and battery modules 630 and 640 are also connected in series. Although the battery pack 600 is shown as including 4 battery modules, it is understood that there may be more battery modules in a single battery pack. The discharge control arrangement 601 is adapted to double the output voltage, wherein the positive terminal of the battery module 610 is connected to the negative terminal of the battery module 620, the positive terminal of the battery module 620 is output to the associated control switch 650, while the negative terminal of the battery module 610 is connectable to the chassis ground of the electric vehicle.

In a manner similar to that described with reference to fig. 1, when the key at key switch 605 is pressed ON, signal DBEN1 is effective to activate control switch 650 to control the voltage output of the pair of battery modules 610 and 620 connected in series. The activation signal key also closes all of the push-to-talk switches 611, 621, …, 641 in the discharge control configuration 601. This enables each pair of battery modules 610/620, 630/640 … in the battery pack 600 to be monitored by comparators 623, 643 respectively disposed in associated control switches 650, 660. The monitored voltages represent the amount of energy per pair of battery modules in the battery pack 600, respectively, and are observable at the outputs of the respective buffers 627, 647.

The output voltage 2XVIN from the pair of battery modules 610, 620 is attenuated by the voltage dividers R1, R2 before being applied to the comparator 623 provided in the control switch 650. The voltage 2XVIN is twice the single battery module output voltage VIN. The comparator 623 is adapted to compare the decaying voltage with a reference voltage 2XVref, which may be a value of, for example, twice the voltage Vref shown in fig. 1, or another voltage value. The voltage 2XVref may be an internal voltage or an external input to control switch 650.

When there is sufficient energy in the pair of battery modules 610, 620, the output of the comparator 623 in the associated control switch 650 will be a logic high. If signal DBEN1 is also asserted, enable-AND 624 is asserted to transfer voltage 2XVIN from the pair of series-connected battery modules 610, 620 to the output node VBPACK of battery pack 600. However, if the decay voltage input to comparator 623 drops below 2XVref, then the transmitting device 625 in control switch 650 will be disabled AND link-AND 628 will assert the control output signal DBEN2 to turn off the pair of combined switches 612, 622 coupled to battery modules 610, 620 while enabling the subsequent control switch 660 to output the voltage to node VBPACK twice if both battery modules have sufficient energy available.

When the key switch 605 is pressed ON, a display device (e.g., LEDs 629, 649, etc., shown in fig. 6) may be illuminated to indicate the energy status of all the subgroups of battery modules 610, 620 and 630, 640 in the battery pack 600. In a discharge control configuration 601 where the voltage at the output is doubled, the number of control switches can be reduced by half.

In one embodiment, to increase the output current of the battery pack, a subset of the control switches in the discharge control chain may be activated together so that their associated battery modules in the battery pack may output current in parallel. This can be achieved by: connecting the same enable input to all control switches in the subgroup and then enabling the enable input to be active for all control switches in the subgroup of control switches, all relevant battery modules may be activated to output current simultaneously to boost the current output. Furthermore, the control outputs of all control switches in a subgroup of control switches may be ored together to become the new enable input of the subsequent subgroup of control switches for parallel current output. The control switch for boosting the current and higher voltage outputs is the same as the control switch for normal current and voltage outputs.

Fig. 7 shows an exemplary sequential discharge control configuration 701 with doubled output current from a battery pack 700. Although the battery pack 700 is shown to include only four battery modules, it is understood that the battery pack may include more battery modules. In the battery pack 700, when the key at the key switch 705 is pressed to ON, the enable signal DBEN1 is active to activate the two control switches 750, 760 so that the energy VIN1, VIN2 of the two battery modules 710, 720 associated therewith is simultaneously output to the battery pack output node VBPACK through the two control switches 750, 760 to double the output current. The outputs of all control switches in the battery pack are ored together at VBPACK.

If the energy of either battery module 710, 720 is depleted, then the output of at least one of the link-AND 717, 727 will go high. The output current can also be doubled to VBPACK by connecting the outputs of the two link-AND 717, 727 together at OR gate 728, OR as the output of node DBEN3 will go high to activate a subsequent pair of control switches 770, 780 in the discharge control configuration 701. Assertion of signal DBEN3 also opens a pair of junction switches 712, 722 coupled to the outputs of battery modules 710, 720, which prevents further depletion of energy in the depleted pair of battery modules 710, 720.

In one embodiment, similar control switches may also be used to output higher voltages and higher current outputs from the battery pack. This is achieved by: the battery module subsets of the battery module subsets are serially connected in advance to increase the output voltage, and then a plurality of similar battery module subsets are activated to simultaneously output power under the control of the control switch subsets to increase the output current, wherein each control switch of the control switch subsets controls the power output of the battery module subsets. The control outputs of the control switch subsets are ored together to become a new enable control signal to enable the next control switch subset in the discharge control configuration 701. If the energy in any battery module subgroup falls below a predefined value, a new OR control output is enabled.

Conclusion(s)

By dividing the battery pack into a plurality of detachable and replaceable battery modules and using a discharge control chain to control the orderly discharge of the power of the battery modules, the battery configuration in the electric vehicle will be more versatile and effectively address the charging limitations, enabling seamless power switching between the battery modules without an external microcontroller.

By grouping the series connected battery modules in the battery pack and their associated control switches in parallel in a discharge control configuration for power output control, the output voltage and output current of the battery pack is also adjustable. The battery protection device may also be included in a discharge control configuration to prevent false battery discharge when the electric vehicle is turned off and to inhibit degradation of the depleted battery module due to deep energy depletion when the electric vehicle is powered up.

Instead of continually pursuing larger battery packs with higher energy storage capacities to increase mileage, it is more costly for consumers at higher electric vehicle costs, which may ultimately lead to heavier electric vehicles, which is disadvantageous for electric vehicles. The adoption of removable and replaceable battery modules in the battery pack is an effective way to address the mileage anxiety of electric vehicles, which potentially reduces the cost of electric vehicles.

For electric vehicles, it is not appropriate to always carry a large battery pack. If the electric automobile is used for daily short-distance commute, some battery modules are removed from the electric automobile to reduce the weight expenditure of the automobile to the greatest extent, and more battery modules are added for the electric automobile under the free cutting of an electric automobile owner so as to drive for a longer distance, so that the energy use efficiency of the electric automobile can be improved. It may accelerate the acceptance of electric vehicles, if the price of electric vehicles can be reduced by reducing the cost of battery possession, and if the battery module can be widely used, so that some of the depleted batteries can be easily replaced in most places or charged in a short time, just as if the vehicles were rapidly refueled at a gas station on the road, bringing more convenience to the electric vehicle driver.

Claims

1. A control switch, comprising:

an enable input port for receiving an enable input signal;

a control output port for enabling a control output signal;

a power input port;

a power output port;

a power transmission device;

comparison means for comparing the external voltage with a reference voltage to generate a comparison output;

a switch control comprising 1:2 demultiplexing logic having a demultiplexing input coupled to the enable input signal and a demultiplexing select signal coupled to the compare output, wherein,

when the enable input signal is valid, the demultiplexed input is forwarded by the 1:2 demultiplexing logic to a first demultiplexed output port to cause the power transfer means to start up, which when the comparison output is valid, transfers input power received at the power input port from a battery associated with the control switch to the power output port, and

the demultiplexed input is forwarded by the 1:2 demultiplexing logic to a second demultiplexed output port to enable the control output signal, which is the input of the enable input port as the demultiplexed input of the subsequent control switch when the demultiplexed selection signal is not enabled.

2. The control switch of claim 1, wherein the control output port of the control switch is linked to the enable input port of the subsequent switch, thereby forming a link-control chain to control automatic power switching of an associated battery.

3. The control switch of claim 1, wherein the 1:2 demultiplexing logic facilitates simultaneous switching between the control switch and a subsequent control switch when the demultiplexed select signal changes state.

4. The control switch of claim 1, wherein the power input port comprises a slew rate control.

5. The control switch of claim 1, wherein the de-multiplexing select signal is inactive when one or more anomalies of current surge, overvoltage latch-up, or thermal overheating occur.

6. The control switch of claim 1, wherein the power transfer device is selected from the group consisting of: NMOS Field Effect Transistors (FETs), PMOS field effect transistors, a pair of back-to-back NMOS field effect transistors, a pair of back-to-back PMOS field effect transistors, bipolar junction transistors, electromechanical relays, and solid state relays.

7. The control switch of claim 1, wherein the comparison means is an operational amplifier, wherein the comparison output is saturated in an active state when the external voltage is higher than the reference voltage, and is saturated in an inactive state when the external voltage is lower than the reference voltage.

8. The control switch of claim 1, wherein the control switch further comprises a status output bit adapted for external observation of the comparison output.

9. The control switch of claim 1, wherein the comparison means is an AC-DC converter (ADC), wherein an output of the ADC is input to a size comparator to generate the comparison output, wherein the comparison output is active when the output of the ADC is above a set point applied to the size comparator, and is inactive when the output of the ADC is below the set point.

10. The control switch of claim 9, wherein the set point in the magnitude comparator is embedded in the control switch or programmed in an internal memory device.

11. The control switch of claim 9, wherein the control switch further comprises a status I/O port coupled to the I/O interface block and adapted to display a device to initiate observation of the output of the ADC.

12. The control switch of claim 1, wherein the external voltage is a decaying voltage of the input power.

13. The control switch of claim 1, wherein the control switch is implemented as an integrated circuit.

14. The control switch of claim 1, wherein the control switch is implemented as a discrete electronic device.

15. The control switch of claim 1, wherein the control switch is implemented as a set of chiplets assembled in a multi-chip package (MCP).

16. A discharge system comprising a plurality of batteries and a plurality of control switches, wherein a first control switch of the plurality of control switches comprises:

an enable input port for receiving an enable input signal;

a control output port for enabling a control output signal;

a power input port;

a power output port;

a power transmission device;

a switch control, the control switch comprising 1:2 demultiplexing logic having a demultiplexing input coupled to the enable input signal and a demultiplexing select signal coupled to the compare output, wherein,

when the enable input signal is valid, the de-multiplexing input is forwarded by the 1:2 de-multiplexing logic to a first de-multiplexing output port to enable the power transfer device, which transfers input power received at the power input port from a first battery associated with the first control switch to the power output port when the comparison output is valid, and

When the de-multiplexing select signal is inactive and when the second battery associated with the second control switch has sufficient energy for output, the de-multiplexing input is forwarded by the 1:2 de-multiplexing logic to a second de-multiplexing output port to enable the control output signal coupled to the enable input port to be active as an enable input signal to activate a second control switch of the plurality of control switches to transfer power received from a second battery to a power output port of the second control switch; and is also provided with

The control output port of the first control switch is linked to an enable input port of the second control switch, forming a control chain to control power switching of an associated battery in the discharge system.

17. The discharge system of claim 16, wherein the switching control initiates simultaneous switching between the first control switch and the second control switch, and further initiates simultaneous switching between the first battery and the second battery when the demultiplexed selection signal changes state.

18. The discharge system of claim 16, wherein the discharge system is a battery system in an Electric Vehicle (EV), the battery system being divided into a plurality of batteries controlled by a plurality of associated control switches connected in sequence to form the control chain to control discharge of a plurality of batteries in the battery system, the plurality of batteries including the first battery and the second battery.

19. The discharge system of claim 18, wherein the plurality of batteries are removable and replaceable.

20. The discharge system of claim 16, wherein the power output port of the first control switch and the power output port of the second control switch are coupled to each other to provide an output power of the discharge system.

21. The discharge system of claim 16, wherein the de-multiplexing select signal is inactive when one or more anomalies of over-voltage lockout, thermal overheating, or current surge occur.

22. The discharge system of claim 16 wherein the comparison means is an operational amplifier wherein the comparison output is saturated in an active state when the external voltage is above the reference voltage and saturated in an inactive state when the external voltage is below the reference voltage.

23. The discharge system of claim 16, wherein the comparison device is an AC-DC converter (ADC), wherein an output of the ADC is input to a size comparator to generate the comparison output, wherein,

the comparison output is active when the output of the ADC is above a set point applied to the size comparator and inactive when the output of the ADC is below the set point.

24. The discharge system of claim 16, wherein the first battery and the second battery are connected in series prior to input to a control switch of the plurality of control switches to increase an output voltage of the discharge system.

25. The discharge system of claim 16, wherein the enable input port of the first control switch is coupled to the enable input port of the second control switch to form a set of coupled control switches such that the first battery and the second battery associated with the set of coupled control switches can output power in parallel to increase an output current for the discharge system.

26. The discharge system of claim 25, wherein the signal output by the control output port of the first control switch is ored with the signal output by the control output port of the second control switch to form a second enable input signal to activate a subsequent set of coupled control switches of the plurality of control switches for activating an associated set of the plurality of batteries to output current in parallel.

27. The discharge system of claim 16, wherein when a control output signal in a kth control switch of the plurality of control switches is active and if the comparison output of a kth+1 control switch is inactive, then the control output signal from a kth control switch will cause a kth+2 control switch associated with a kth+2 battery of the plurality of batteries to be activated to detect whether a voltage received from the kth+2 battery exceeds the reference voltage to determine whether the kth+2 battery will be activated to output power to the power distribution system.

28. An apparatus adapted to protect a battery in a discharge system, wherein an input port of the apparatus is coupled to an output port of the battery, an output port of the apparatus is coupled to a power input port of a control switch that controls a power output of the battery, wherein the apparatus comprises:

a push-to-talk switch that is turned on when the discharging system is turned off and is turned off when the discharging system is turned on; and

and a combination switch which is closed when the discharging system is closed and is opened when the control switch detects that the power of the battery is smaller than a preset value.

29. The apparatus of claim 28, wherein the push-to-talk switch and the combination switch are connected in series.

30. The device of claim 28, wherein the device comprises a protection switch controlled by one or more logic gates performing a boolean and function, wherein,

when the discharge system is turned on, the output of the AND function is enabled, thereby closing the protection switch;

when the discharging system is turned off, the output of the AND function is inverted to turn on the protection switch; and

When the control switch detects that the power in the battery is less than a predetermined value, the output of the AND function is inverted to open the protection switch to prevent deep power drain, wherein when the discharge system is turned on, the output of the AND function is inverted.

31. A power supply system comprising a plurality of batteries; a plurality of battery protection devices, each battery protection device coupled to a different one of the plurality of batteries; and a plurality of control switches, each control switch coupled to a different one of the plurality of battery protection devices, wherein

Coupling the output power of a kth battery of the plurality of batteries to an input port of a kth battery protection device of the plurality of battery protection devices, an

An output port of the kth protection device is coupled to a power input of a kth control switch of the plurality of control switches; wherein each battery protection device includes:

a push-to-talk switch which is turned on when the power supply system is turned off, which is turned off when the power supply system is turned on, and

a combination switch connected in series with the push-to-talk switch, wherein the combination switch is closed when the power supply system is turned off; the combination switch is turned on when the voltage of the associated battery of the combination switch is detected to be lower than a predetermined value.

32. The power system of claim 31, wherein the push-to-talk switch and the combination switch in each battery protection device are reconfigured as a single protection switch controlled by one or more logic gates performing a boolean and function, wherein,

the output of the AND function is effective to turn off the single protection switch when the power system is on;

when the power system is turned off, the output of the AND function is disabled to open the single protection switch; and

when the coupled control switch detects that the power in the coupled battery is less than the predetermined value, the output of the and function is disabled to open the single protection switch to prevent deep power drain of the coupled battery, wherein the output of the and function remains disabled while the power system is on.

33. The power system of claim 31, wherein when the power system is on, the enable input to the first control switch is effective to activate the first control switch and to turn off all of the push-to-talk switches in the plurality of battery protection devices such that the power output of each of the plurality of batteries is connected to the power input of its coupled control switch of the plurality of control switches, wherein

When it is detected that the power of the first battery is less than a predetermined value, the first control output from the first control switch is enabled so as to:

starting a second control switch to activate a second module for power output;

turning off a first combination switch of the first battery protection device to disconnect the first battery from the power system; and

when it is detected that the power in the second battery is less than the predefined level, a second control output from the second control switch is enabled so as to:

starting a third control switch to activate a third battery for power output; and

and turning off a second combination switch of the second battery protection device to disconnect the second battery from the power supply system.