CN111361420A - Power battery system and electric automobile - Google Patents

Abstract

The invention discloses a power battery system and an electric vehicle. The power battery system includes a vehicle controller and at least two discrete working battery modules; The working battery module is detachable and fixed on the electric vehicle between the negative terminals of the device; the working battery module includes a first cell group, a first BMS and a first switch unit, and the first BMS monitors the first cell group When a fault occurs, the action of the first switch unit is controlled to disconnect the electrical connection between the working battery module and the power battery system. The present invention can disconnect the faulty working battery module and the power battery system from the electrical connection, and separate it from the chassis of the electric vehicle, so as to avoid the thermal runaway of the working battery module from spreading to other working battery modules and causing injury to people and vehicles. In the maintenance, only the faulty working battery module needs to be replaced, and there is no need to abandon other working battery modules and the whole vehicle, which saves the maintenance cost.

Description

A power battery system and electric vehicle

technical field

The invention relates to the technical field of power batteries, in particular to a power battery system and an electric vehicle.

Background technique

With the prominent problems of energy consumption, resource shortage and environmental pollution caused by automobiles, electric vehicles, as an energy-saving and environmentally friendly means of transportation, have attracted much attention due to their significant advantages of high efficiency, energy saving and low emissions. Due to its high specific energy, low self-discharge rate and long cycle life, lithium-ion power batteries are currently the most practical energy source for pure electric vehicles.

The current power battery system of electric vehicles is usually composed of multiple cells in series and parallel to form a cell group and packaged into a unit module. The modules are then connected in series and packaged into a battery pack. The aluminum alloy lower box and the upper cover are encapsulated, and will be installed on the chassis of the vehicle after encapsulation.

However, since all modules are packaged into battery packs, it is very difficult to disassemble and disassemble them. Once a cell or other components fail, it is very difficult to replace the cells or parts. Therefore, when a certain battery cell is thermally out of control, the entire battery pack or the entire vehicle has to be abandoned, and it may also cause casualties, which is also a huge loss to the market image of the car company.

SUMMARY OF THE INVENTION

The embodiments of the present invention provide a power battery system and an electric vehicle. When a working battery module fails, the electrical connection between the working battery module and the power battery system is disconnected, and the electric vehicle is separated from the chassis of the electric vehicle. The thermal runaway of the working battery module affects other working battery modules, causing damage to people and vehicles. In the follow-up maintenance, only the faulty working battery module needs to be replaced, and there is no need to abandon other working battery modules and the whole vehicle. Save maintenance costs.

In a first aspect, an embodiment of the present invention provides a power battery system, including: a vehicle controller and at least two discrete working battery modules;

The at least two discrete working battery modules are connected in series to the positive terminal of the vehicle controller and the negative terminal of the vehicle controller, and the working battery modules are detachably fixed on the electric vehicle;

The working battery module includes a first cell group, a first BMS and a first switch unit, the first BMS is respectively connected to the vehicle controller and the first switch unit, and the first BMS is used for When the failure of the first battery cell group is detected, the first switch unit is controlled to act so as to disconnect the working battery module from the power battery system.

Optionally, the first switch unit includes a first series switch and a first bypass switch;

The positive pole of the first battery cell group is connected to the first terminal of the first series switch, and the second terminal of the first series switch is connected to the positive terminal of the working battery module;

The negative pole of the first cell group is connected to the negative pole of the working battery module;

The first end of the first bypass switch is connected to the negative terminal of the working battery module, and the second end of the first bypass switch is connected to the positive terminal of the working battery module;

The control terminal of the first series switch and the control terminal of the first bypass switch are both connected to the first BMS.

Optionally, the first series switch includes a MOS transistor switch and a relay switch, and the first bypass switch includes a relay switch.

Optionally, the power battery system further includes a backup battery module, and the backup battery module is connected in series with the working battery module;

The backup battery module includes a second cell group, a second BMS and a second switch unit, and the second BMS is used to control the action of the second switch unit when the first cell group fails, So that the backup battery module is connected in series to the series loop between the positive terminal of the vehicle controller and the negative terminal of the vehicle controller.

Optionally, the second switch unit includes a second series switch and a second bypass switch;

The positive pole of the second battery cell group is connected to the first terminal of the second series switch, and the second terminal of the second series switch is connected to the positive terminal of the backup battery module;

The negative pole of the second battery cell group is connected to the negative pole of the backup battery module;

The first end of the second bypass switch is connected to the negative terminal of the backup battery module, and the second end of the second bypass switch is connected to the positive terminal of the backup battery module;

The control terminal of the second series switch and the control terminal of the second bypass switch are both connected to the second BMS, and the second BMS is connected to the vehicle controller.

Optionally, the second series switch includes a MOS transistor switch and a relay switch, and the second bypass switch includes a relay switch.

Optionally, the second switch unit includes a second series switch, a second bypass switch, and a single-pole double-throw switch, and the power battery system further includes a master control switch;

The master control switch is arranged in the series loop formed by the at least two discrete working battery modules, and is close to the positive terminal of the vehicle controller or the negative terminal of the vehicle controller. The control end of the switch is connected with the vehicle controller;

The positive pole of the second cell group is connected to the first end of the second series switch, and the second end of the second series switch is connected to the moving end of the SPDT switch;

The first stationary terminal of the SPDT switch is connected to the positive terminal of the vehicle controller, and the second stationary terminal of the SPDT switch is connected to the positive terminal of the backup battery module;

The negative pole of the second battery cell group is connected to the negative pole of the backup battery module;

The first end of the second bypass switch is connected to the negative terminal of the backup battery module, and the second end of the second bypass switch is connected to the positive terminal of the backup battery module;

The control terminal of the second series switch, the control terminal of the second bypass switch and the control terminal of the SPDT switch are all connected to the second BMS, and the second BMS is connected to the vehicle control device connection.

Optionally, the SPDT switch and the master control switch include a relay switch, the second series switch includes a MOS transistor switch and a relay switch, and the second bypass switch includes a relay switch.

Optionally, the positive terminal of the working battery module and the negative terminal of the working battery module are connected in a series loop formed by the at least two separate working battery modules through a quick connector;

The positive terminal of the backup battery module and the negative terminal of the backup battery module are connected in the series circuit through a quick connector.

In a second aspect, an embodiment of the present invention further provides an electric vehicle, including the power battery system provided in the first aspect of the present invention.

The power battery system provided by the embodiment of the present invention includes a vehicle controller and at least two discrete working battery modules. The working battery module is detachably fixed on the electric vehicle, and the working battery module includes a first cell group, a third A BMS and a first switch unit, where the first BMS is used to control the action of the first switch unit when a failure of the first cell group is detected, so as to disconnect the working battery module from the power battery system. Avoid damage or safety accidents caused by the continuous operation of the first cell group in the case of a fault. At the same time, the first BMS reports the fault information to the vehicle controller. According to the severity of the fault, the vehicle controller can choose to unload the faulty working battery module from the chassis of the electric vehicle to avoid the failure of the working battery module. Thermal runaway spreads to other working battery modules, causing damage to people and vehicles. In the follow-up maintenance, only the faulty working battery module needs to be replaced, and there is no need to abandon other working battery modules and the whole vehicle, which saves maintenance costs.

Description of drawings

The present invention will be described in further detail below according to the accompanying drawings and embodiments.

FIG. 1 is a schematic structural diagram of a power battery system according to an embodiment of the present invention;

2 is a schematic structural diagram of another power battery system provided by an embodiment of the present invention;

FIG. 3 is a schematic structural diagram of another power battery system according to an embodiment of the present invention.

Detailed ways

In order to make the technical problems solved by the present invention, the technical solutions adopted and the technical effects achieved more clearly, the technical solutions of the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings. Obviously, the described embodiments are only the present invention. Some examples, but not all examples. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts shall fall within the protection scope of the present invention.

In the description of the present invention, unless otherwise expressly specified and limited, the terms "connected", "connected" and "fixed" should be understood in a broad sense, for example, it may be a fixed connection, a detachable connection, or an integrated ; It can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood in specific situations.

In the present invention, unless otherwise expressly specified and limited, a first feature "on" or "under" a second feature may include the first and second features in direct contact, or may include the first and second features Not directly but through additional features between them. Also, the first feature being "above", "over" and "above" the second feature includes the first feature being directly above and obliquely above the second feature, or simply means that the first feature is level higher than the second feature. The first feature is "below", "below" and "below" the second feature includes the first feature being directly below and diagonally below the second feature, or simply means that the first feature has a lower level than the second feature. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.

An embodiment of the present invention provides a power battery system. FIG. 1 is a schematic structural diagram of a power battery system provided by an embodiment of the present invention. As shown in FIG. 1 , the power battery system includes: a vehicle controller (Vehicle ControlUnit, VCU) and at least two discrete working battery modules, exemplarily, three working battery modules M1-M3 are used as an example for description in FIG. 1 .

The so-called sub-immediate working battery modules are set up independently, rather than multiple working battery modules being wrapped in a closed box. In order to ensure the mechanical strength of each working battery module and avoid external damage, the shell of each working battery module is designed to be strengthened or thickened. Each working battery module adopts a special mechanical structure or electrical structure, such as an electronically controlled cylinder locking mechanism or an electronically controlled gear locking mechanism, and can be detachably fixed on the chassis of the electric vehicle.

Each working battery module includes a positive terminal and a negative terminal, and at least two working battery modules are connected in series between the positive terminal V+ of the vehicle controller VCU and the negative terminal V- of the vehicle controller VCU. Exemplarily, as shown in Figure 1, the working battery modules M1-M3 are connected in series end to end, wherein the negative terminal M1- of the working battery module M1 is connected to the negative terminal V- of the vehicle controller VCU, and the positive terminal M3+ of M3 It is connected to the positive terminal V+ of the vehicle controller VCU, that is, the working battery modules M1-M3 supply power to the vehicle controller VCU. The vehicle controller VCU converts the voltage to the voltage required by the vehicle, and supplies power to the vehicle loads. , Loads can be motors.

Each working battery module includes a first cell group, a first BMS and a first switch unit. Among them, the battery cell group includes a plurality of battery cells connected in series or in parallel, and the BMS is a battery management system (Battery Management System), which is used to realize dynamic monitoring of the working battery module. Exemplarily, as shown in FIG. 1, in the embodiment of the present invention, the working battery module M1 includes a first cell group C1, a first BMS (BMS1), and a first switch unit Q1; the working battery module M2 includes a first battery module M2. A cell group C2, a first BMS (BMS2) and a first switch unit Q2 (not shown in the figure); the working battery module M3 includes a first cell group C3, a first BMS (BMS3) and a first switch unit Q3 (not shown in the figure).

The first BMS is respectively connected to the vehicle controller VCU and the first switch unit. By way of example, the present invention will be described by taking the working battery module M1 as an example.

In the working battery module M1, the first BMS (BMS1) is respectively connected with the first switch unit Q1, the vehicle controller VCU and the first cell group C1. The first cell group C1 is provided with sensors and collectors, for example, one or more of a temperature sensor, an air pressure sensor, a current collector and a voltage collector, which are used when the power battery system is working (charging or discharging) Collect the temperature, air pressure, current and/or voltage of the first cell group C1, and transmit the temperature information, air pressure information, current information and/or voltage information to the first BMS (BMS1).

The first BMS (BMS1) determines whether there is a fault in the first cell group C1 according to the temperature information, air pressure information, current information and/or voltage information, such as cell failure or thermal runaway, when the first BMS (BMS1) determines that the first cell group C1 is faulty. When the cell group C1 fails, the first switch unit Q1 is controlled to act so as to disconnect the working battery module M1 from the power battery system, so as to avoid damage caused by the continuous operation of the first cell group C1 in the event of a fault. or safety incident. At the same time, the first BMS (BMS1) reports the fault information to the vehicle controller VCU. According to the severity of the fault, the vehicle controller VCU can choose to be repaired or directly unload the working battery module M1 from the chassis of the electric vehicle. . For example, when the fault is not serious (such as cell failure), you can choose to repair the working battery module M1 later; when the fault is serious (such as thermal runaway), the vehicle controller VCU controls the electronically controlled cylinder locking mechanism or The action of the electronically controlled gear locking mechanism separates the working battery module M1 from the chassis of the electric vehicle, so as to avoid thermal runaway of the working battery module M1 and other working battery modules from causing damage to people and vehicles. In the follow-up maintenance, only the faulty working battery module M1 needs to be replaced, and there is no need to abandon other working battery modules and the whole vehicle, which saves maintenance costs.

The above embodiment describes the working process of the power battery system provided by the embodiment of the present invention when the working battery module M1 fails. When other working battery modules fail, the working process of the power battery system is similar to this, and the present invention implements The example will not be repeated here.

The power battery system provided by the embodiment of the present invention includes a vehicle controller and at least two discrete working battery modules. The working battery module is detachably fixed on the electric vehicle, and the working battery module includes a first cell group, a third A BMS and a first switch unit, where the first BMS is used to control the action of the first switch unit when a failure of the first cell group is detected, so as to disconnect the working battery module from the power battery system. Avoid damage or safety accidents caused by the continuous operation of the first cell group in the case of a fault. At the same time, the first BMS reports the fault information to the vehicle controller. According to the severity of the fault, the vehicle controller can choose to unload the faulty working battery module from the chassis of the electric vehicle to avoid the failure of the working battery module. Thermal runaway spreads to other working battery modules, causing damage to people and vehicles. In the follow-up maintenance, only the faulty working battery module needs to be replaced, and there is no need to abandon other working battery modules and the whole vehicle, which saves maintenance costs.

In some embodiments of the present invention, the first switch unit includes a first series switch and a first bypass switch. Illustratively, the embodiment of the present invention is described by taking the working battery module M1 as an example.

Specifically, as shown in FIG. 1 , in the working battery module M1 , the first switch unit Q1 includes a first bypass switch K11 and a first series switch K12 . The positive electrode of the first cell group C1 is connected to the first terminal of the first series switch K12, and the second terminal of the first series switch K12 is connected to the positive terminal M1+ of the working battery module M1. The negative pole of the first cell group C1 is connected to the negative pole M1- of the working battery module M. The first end of the first bypass switch K11 is connected to the negative terminal M1- of the working battery module M1, and the second end of the first bypass switch K11 is connected to the positive terminal M1+ of the working battery module M1. The control terminal of the first series switch K12 and the control terminal of the first bypass switch K11 are both connected to the first BMS ( BMS1 ).

Specifically, during the normal operation of the power battery system, the first bypass switch K11 is a normally open switch, and the first series switch is a normally closed switch. When the first BMS (BMS1) detects that the first cell group C1 is faulty, it controls the first bypass switch K11 to close and the first series switch to open, thereby disconnecting the working battery module M1 from the power battery system. .

Similarly, as shown in FIG. 1 , in the working battery module M2, the first switch unit Q2 includes a first bypass switch K21 and a first series switch K22. In the working battery module M3, the first switch unit Q3 includes a first bypass switch K31 and a first series switch K32. The connection of the first bypass switch K21 and the first series switch K22 in the first switch unit Q2 and the connection of the first bypass switch K31 and the first series switch K32 in the first switch unit Q3 are the same as those in the first switch unit Q1. The connection conditions of the first bypass switch K11 and the first series switch K12 are similar, and details are not described herein again in this embodiment of the present invention.

Exemplarily, in some embodiments of the present invention, the first series switches K12 , K22 and K32 may be MOS transistor switches or relay switches. The MOS transistor switches have the advantage of fast response speed, which can improve the response speed of the system. The first bypass switches K11, K21 and K31 may be relay switches.

In another embodiment of the present invention, on the basis of the above-mentioned embodiment, the power battery system further includes a backup battery module, and the backup battery module is connected in series with the working battery module. Exemplarily, FIG. 2 is a schematic structural diagram of another power battery system provided by an embodiment of the present invention. As shown in FIG. 2 , the power battery system further includes a backup battery module M0, a backup battery module M0 and a working battery module. M1, M2 and M3 are connected in series. Specifically, the negative terminal M0- of the backup battery module M0 is connected to the negative terminal V- of the vehicle controller VCU, and the positive terminal M0+ of the backup battery module M0 is connected to the negative terminal M1- of the working battery module M1.

The backup battery module M0 includes a second cell group C0, a second BMS (BMS0) and a second switch unit Q0 (not shown in the figure), and the second BMS (BMSO) is used to monitor the work of the second cell group C0 In this case, the second BMS (BMS0) is respectively connected with the second switch unit Q0 and the vehicle controller VCU.

Specifically, during the normal operation of the power battery system, the backup battery module M0 is not connected to the power battery system. When a working battery module (such as working battery module M1) fails, the first BMS (BMS1) reports the fault information to the vehicle controller VCU, and the vehicle controller VCU reports to the second BMS according to the fault information. (BMS0) Send a control command to control the action of the second switch unit Q0, so that the backup battery module is connected to the series circuit between the positive port of the vehicle controller and the negative port of the vehicle controller, and replaces the disconnected due to fault. The working battery module M1 avoids the problem that the output voltage of the power battery system decreases after the working battery module M1 is disconnected, and ensures the output stability of the power battery system.

In some embodiments of the present invention, the second switch unit includes a second series switch and a second bypass switch. Specifically, as shown in FIG. 2, in the backup battery module M0, the second switch unit Q0 includes a second bypass switch K01 and a second series switch K02. The anode of the second cell group C0 is connected to the first terminal of the second series switch K02, and the second terminal of the second series switch K02 is connected to the anode terminal M0+ of the backup battery module M0. The negative pole of the second cell group C0 is connected to the negative pole M0- of the backup battery module M0. The first end of the second bypass switch K01 is connected to the negative terminal M0- of the backup battery module M0, and the second end of the second bypass switch K01 is connected to the positive terminal M0+ of the backup battery module M0. The control terminal of the second series switch K02 and the control terminal of the second bypass switch K01 are both connected to the second BMS (BMS0), which is connected to the vehicle controller VCU.

Specifically, during the normal operation of the power battery system, the second bypass switch K01 is a normally closed switch, and the second series switch K02 is a normally open switch. When the first BMS (BMS1) detects that the first cell group C1 is faulty, it controls the first bypass switch K11 to close, and the first series switch K12 to open, thereby disconnecting the working battery module M1 from the power battery system. connect. At the same time, the first BMS (BMS1) reports the fault information to the vehicle controller VCU, and the vehicle controller VCU sends a control command to the second BMS (BMS0) according to the fault information, and the second BMS (BMS0) according to the control command , control the second bypass switch K01 to open, and the second series switch K02 to close, so that the backup battery module is connected to the series circuit between the positive port of the vehicle controller and the negative terminal of the vehicle controller, and replaces the fault caused by the fault. The disconnected working battery module M1 avoids the problem that the output voltage of the power battery system decreases after the working battery module M1 is disconnected, and ensures the output stability of the power battery system.

In addition, when M2, M3, and M4 are all working normally, when the driver has additional driving power demand, the vehicle controller VCU can send a control command to the second BMS (BMS0) to control the disconnection of the second bypass. Switch K01 and close the second series switch K02, so that the backup battery module M0 is connected in series, the output voltage of the entire power battery system is increased by 1/3, and the power output capability of the power battery is improved by increasing the output voltage. The vehicle provides more power. Another advantage of this is that when the same power is output, the peak discharge current can be reduced, and the aging or loss of the battery can be reduced.

When the ambient temperature is low, according to the characteristics of the lithium-ion power battery, the peak current or peak power of the battery will be relatively limited, which will reduce the power performance of the vehicle in a low temperature environment. In this case, the overall power output capability of the power battery can also be increased by connecting the backup battery module M0 to improve the power performance of the vehicle at low temperature.

Exemplarily, in the above embodiment, the first series switches K12, K22 and K32 and the second series switch K02 can be MOS switches and relay switches. The MOS switches have the advantage of fast response speed, which can improve the response speed of the system. The first bypass switches K11, K21 and K31 and the second bypass switch K01 may be relay switches.

In another embodiment of the present invention, the second switch unit includes a second series switch, a second bypass switch and a single-pole double-throw switch, and the power battery system further includes a master control switch. Exemplarily, this embodiment provides another implementation manner of the second switch unit Q0. Therefore, the working battery modules M1-M3 are the same as those in the previous embodiment, and are not repeated here.

As shown in FIG. 3 , in the backup battery module M0 , the second switch unit Q0 includes a second bypass switch K01 , a second series switch K02 and a single-pole double-throw switch KS, and the power battery system further includes a master control switch S0 . The master control switch S0 is set in the series circuit, and is close to the positive terminal V+ port of the vehicle controller VCU or the negative terminal V- of the vehicle controller VCU. The control end of the master control switch S0 is connected to the vehicle controller VCU. In the embodiment of the invention, the master control switch S0 is connected between the negative terminal V- of the vehicle controller VCU and the negative terminal M0- of the backup battery module M0.

The positive pole of the second cell group C0 is connected to the first end of the second series switch K02, the second end of the second series switch K02 is connected to the moving end a of the SPDT switch KS, and the moving end a is provided with a blade. The first stationary terminal b of the SPDT switch KS is connected to the positive terminal V+ of the vehicle controller VCU, and the second stationary terminal c of the SPDT switch KS is connected to the positive terminal M0+ of the backup battery module M0. The negative pole of the second cell group C0 is connected to the negative pole M0- of the backup battery module M0. The first end of the second bypass switch K01 is connected to the negative terminal M0- of the backup battery module M0, and the second end of the second bypass switch K01 is connected to the positive terminal M0+ of the backup battery module M0. The control terminal of the second series switch K02, the control terminal of the second bypass switch K01 and the control terminal of the SPDT switch KS are all connected to the second BMS (BMS0), and the second BMS (BMS0) is connected to the vehicle controller VCU .

Specifically, when the power battery system is working normally, the master control switch S0 is closed, the first bypass switches K11, K21 and K31 are kept open, the first series switches K12, K22 and K32 are kept closed, and the second bypass switch K01 is kept open When closed, the second series switch K02 remains disconnected, and the blade of the SPDT switch KS is in contact with the second non-moving terminal c. In this way, the working battery modules M1-M3 are connected in series to the circuit to supply power to the vehicle controller VCU.

When a working battery module fails, for example, when the first BMS (BMS1) detects the failure of the first cell group C1, the first bypass switch K11 is controlled to be closed, and the first series switch K12 is opened, thereby making the The working battery module M1 is electrically disconnected from the power battery system. At the same time, the first BMS (BMS1) reports the fault information to the vehicle controller VCU, and the vehicle controller VCU sends a control command to the second BMS (BMS0) according to the fault information, and the second BMS (BMS0) according to the control command , control the second bypass switch K01 to open, and the second series switch K02 to close, so that the backup battery module is connected to the series circuit between the positive port of the vehicle controller and the negative terminal of the vehicle controller, and replaces the fault caused by the fault. The disconnected working battery module M1 avoids the problem that the output voltage of the power battery system decreases after the working battery module M1 is disconnected, and ensures the output stability of the power battery system.

In addition, when M2, M3, and M4 are all working normally, when the driver has additional driving power demand, the vehicle controller VCU can send a control command to the second BMS (BMS0) to control the disconnection of the second bypass. Switch K01 and close the second series switch K02, so that the backup battery module M0 is connected in series, the output voltage of the entire power battery system is increased by 1/3, and the power output capability of the power battery is improved by increasing the output voltage. The vehicle provides more power. Another advantage of this is that when the same power is output, the peak discharge current can be reduced, and the aging or loss of the battery can be reduced.

When the ambient temperature is low, according to the characteristics of the lithium-ion power battery, the peak current or peak power of the battery will be relatively limited, which will reduce the power performance of the vehicle in a low temperature environment. In this case, the overall power output capability of the power battery can also be increased by connecting the backup battery module M0 to improve the power performance of the vehicle at low temperature.

In addition, in the embodiment of the present invention, the backup battery module M0 can be used to supplement the power of the working battery module with low power alone, or to discharge the working battery module with high power separately, thereby improving the communication between the working battery modules. Balance, improve the overall life of the power battery.

Specifically, as shown in FIG. 3 , taking the working battery module M1 as an example, when the electric vehicle is stationary, each first BMS will collect the voltage of the corresponding first cell group and upload it to the vehicle controller VCU , the voltage reflects the power of the first cell group. When the vehicle controller VCU determines that the power of the working battery module M1 is higher or lower than a certain threshold of the power of other working battery modules, the vehicle controller VCU controls the master control switch S0 to turn off, and sends the power to the first BMS (BMS1 ) sends a control command, the first BMS (BMS1) controls the blade of the SPDT switch KS to contact the first fixed end b, and controls the first bypass switches K11, K21, K31, and the second bypass switch K01 to close, the first A series switch K12 is closed, the first series switches K22 and K23 are open, and the second series switch K02 is closed, so that the working battery module M1 and the backup battery module M0 are connected in parallel, and the backup battery module M0 charges the working battery module M1 , or the working battery module M1 discharges to the backup battery module M0 until the power of the working battery module M1 and other working battery modules is equal or equal. In this way, the balance among the working battery modules can be improved, and the overall life of the power battery can be improved.

Exemplarily, in the above embodiment, the SPDT switch KS and the master control switch S0 can be relay switches, the first series switches K12, K22 and K32 and the second series switch K02 can be MOS transistor switches and relay switches. The switch has the advantage of fast response speed, which can improve the response speed of the system. The first bypass switches K11, K21 and K31 and the second bypass switch K01 may be relay switches.

Exemplarily, in the above-mentioned embodiment, the positive terminal of each working battery module and the negative terminal of the working battery module are connected in a series circuit through a quick connector, and the circuit is realized by a quick connector when installing and disassembling the working battery module. Quick connection and disconnection, improve installation and removal efficiency.

Similarly, the positive terminal M0+ of the backup battery module M0 and the negative terminal M0- of the backup battery module M0 are connected in a series circuit through a quick connector. When installing and removing the backup battery module, the quick connection of the circuit is realized by the quick connector. And disconnect, improve installation and disassembly efficiency.

Exemplarily, in the above embodiment, as shown in FIGS. 1-3 , the vehicle controller VCU may be connected to a DC charging pile (DC Charger) to charge each working battery module and a backup battery module through the DC charging pile. The vehicle controller VCU can also be connected with an on-board charger (On-Board Charger, OBC) to charge external devices on the vehicle through the on-board charger.

The embodiment of the present invention also provides an electric vehicle, the electric vehicle includes the power battery system provided in the above-mentioned embodiment, and has the same functions and effects as the above-mentioned embodiment.

In the description herein, it should be understood that the terms "upper", "lower", "left", "right", etc. are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of description and Operation is simplified, rather than indicating or implying that the device or element referred to must have a particular orientation, be constructed and operate in a particular orientation, and therefore should not be construed as limiting the invention.

In the description of this specification, reference to the description of the terms "an embodiment", "example", etc. means that a particular feature, structure, material or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention middle. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example.

In addition, it should be understood that although this specification is described in terms of embodiments, not each embodiment only includes an independent technical solution, and this description in the specification is only for the sake of clarity, and those skilled in the art should take the specification as a whole , the technical solutions in each embodiment can also be appropriately combined to form other implementations that can be understood by those skilled in the art.

The technical principle of the present invention has been described above with reference to the specific embodiments. These descriptions are only for explaining the principle of the present invention, and should not be construed as limiting the protection scope of the present invention in any way. Based on the explanations herein, those skilled in the art can think of other specific embodiments of the present invention without creative efforts, and these methods will all fall within the protection scope of the present invention.

Claims (10)

1. A power battery system, comprising: a vehicle controller and at least two discrete working battery modules; The at least two discrete working battery modules are connected in series between the positive terminal of the vehicle controller and the negative terminal of the vehicle controller, and the working battery modules are detachably fixed on the electric vehicle; The working battery module includes a first cell group, a first BMS and a first switch unit, the first BMS is respectively connected to the vehicle controller and the first switch unit, and the first BMS is used for When the failure of the first battery cell group is detected, the first switch unit is controlled to act so as to disconnect the working battery module from the power battery system. 2. The power battery system according to claim 1, wherein the first switch unit comprises a first series switch and a first bypass switch; The positive pole of the first battery cell group is connected to the first terminal of the first series switch, and the second terminal of the first series switch is connected to the positive terminal of the working battery module; The negative pole of the first cell group is connected to the negative pole of the working battery module; The first end of the first bypass switch is connected to the negative terminal of the working battery module, and the second end of the first bypass switch is connected to the positive terminal of the working battery module; The control terminal of the first series switch and the control terminal of the first bypass switch are both connected to the first BMS. 3 . The power battery system according to claim 2 , wherein the first series switch comprises a MOS transistor switch and a relay switch, and the first bypass switch comprises a relay switch. 4 . 4. The power battery system according to claim 1, further comprising a backup battery module, the backup battery module is connected in series with the working battery module; The backup battery module includes a second cell group, a second BMS and a second switch unit, and the second BMS is used to control the action of the second switch unit when the first cell group fails, So that the backup battery module is connected in series to the series loop between the positive terminal of the vehicle controller and the negative terminal of the vehicle controller. 5. The power battery system according to claim 4, wherein the second switch unit comprises a second series switch and a second bypass switch; The positive pole of the second battery cell group is connected to the first terminal of the second series switch, and the second terminal of the second series switch is connected to the positive terminal of the backup battery module; The negative pole of the second battery cell group is connected to the negative pole of the backup battery module; The first end of the second bypass switch is connected to the negative terminal of the backup battery module, and the second end of the second bypass switch is connected to the positive terminal of the backup battery module; The control terminal of the second series switch and the control terminal of the second bypass switch are both connected to the second BMS, and the second BMS is connected to the vehicle controller. 6 . The power battery system according to claim 5 , wherein the second series switch comprises a MOS transistor switch and a relay switch, and the second bypass switch comprises a relay switch. 7 . 7. The power battery system according to claim 4, wherein the second switch unit comprises a second series switch, a second bypass switch and a single-pole double-throw switch, and the power battery system further comprises a master control switch; The master control switch is arranged in the series loop formed by the at least two discrete working battery modules, and is close to the positive terminal of the vehicle controller or the negative terminal of the vehicle controller. The control end of the switch is connected with the vehicle controller; The positive pole of the second cell group is connected to the first end of the second series switch, and the second end of the second series switch is connected to the moving end of the SPDT switch; The first stationary terminal of the SPDT switch is connected to the positive terminal of the vehicle controller, and the second stationary terminal of the SPDT switch is connected to the positive terminal of the backup battery module; The negative pole of the second battery cell group is connected to the negative pole of the backup battery module; The first end of the second bypass switch is connected to the negative terminal of the backup battery module, and the second end of the second bypass switch is connected to the positive terminal of the backup battery module; The control terminal of the second series switch, the control terminal of the second bypass switch and the control terminal of the SPDT switch are all connected to the second BMS, and the second BMS is connected to the vehicle control device connection. 8 . The power battery system according to claim 7 , wherein the single-pole double-throw switch and the master control switch comprise a relay switch, the second series switch comprises a MOS tube switch and a relay switch, and the second series switch comprises a MOS tube switch and a relay switch. The secondary bypass switch includes a relay switch. 9. The power battery system according to any one of claims 4-8, wherein the positive terminal of the working battery module and the negative terminal of the working battery module are connected to the at least two terminals through a quick connector. In the series circuit formed by the discrete working battery modules; The positive terminal of the backup battery module and the negative terminal of the backup battery module are connected in the series circuit through a quick connector. 10. An electric vehicle, characterized by comprising the power battery system according to any one of claims 1-9.

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