Battery system, electric device, fast charging method and discharge method

Abstract

The present invention discloses a battery system, electric equipment, a fast charging method and a discharge method. By arranging the battery modules, each battery module is independently arranged, and each battery module can be charged and discharged independently, thereby realizing simultaneous charging of each battery module; thus, compared with the battery system in the prior art, the charging time can be effectively shortened, thereby realizing fast charging; and, only a simple modification of the battery system is required, so that each battery module can be charged independently, thereby reducing the voltage platform used during charging, thereby realizing fast charging of a low-voltage charging platform, and at the same time avoiding an increase in the production cost of the battery system.

Description

Technical Field

[0001] The present invention relates to the field of battery technology, and in particular to a battery system, an electric device, a fast charging method, and a fast discharging method. Background Art

[0002] Current battery systems typically have a voltage range of 250V to 480V. Fast charging requires a voltage platform of at least 800V. This requires significant structural changes to the battery system. Furthermore, the use of a higher voltage platform requires the internal structure of the battery system to meet certain voltage ratings to ensure safe charging, ultimately increasing the manufacturing cost of the battery system. Summary of the Invention

[0003] Embodiments of the present invention provide a battery system, an electric device, a fast charging method, and a discharge method for achieving fast charging of the battery system while avoiding major structural changes to the battery system and increasing the manufacturing cost of the battery system.

[0004] In a first aspect, an embodiment of the present invention provides a battery system, comprising: a plurality of battery modules, each of the battery modules comprising a plurality of single cells;

[0005] The battery module has a total positive output terminal and a total negative output terminal;

[0006] For any of the battery modules: the total positive output terminal and the total negative output terminal are both electrically connected to a battery management system;

[0007] The voltage difference between the total positive output terminal and the total negative output terminal of each battery module is not less than a preset value.

[0008] In a second aspect, an embodiment of the present invention provides an electric device, comprising: a plurality of motors, a battery management system, and the battery system provided by an embodiment of the present invention;

[0009] The number of the motors is less than or equal to the number of the battery modules;

[0010] The motor is configured to operate under the control of the battery management system and driven by at least one of the battery modules.

[0011] In a third aspect, an embodiment of the present invention provides a fast charging method, including:

[0012] Using a voltage platform lower than a preset voltage, fast charging each battery module in the battery system provided by an embodiment of the present invention;

[0013] The preset voltage is a voltage used when fast charging is performed on the battery modules connected in series after the battery modules are connected in series.

[0014] In a fourth aspect, an embodiment of the present invention provides a discharge method, comprising:

[0015] According to a preset discharge strategy, control each battery module in the battery system provided by the embodiment of the present invention to discharge in sequence;

[0016] After the last battery module has finished discharging and it is determined that all the battery modules have residual power, continue to control the battery modules to discharge in sequence according to the discharging strategy until all the battery modules have no residual power;

[0017] The discharge strategy includes:

[0018] For any of the battery modules, discharging is stopped when the released electricity reaches a preset electricity level, and the preset electricity level is less than the electricity level of the battery module when it is fully charged.

[0019] The beneficial effects of the present invention are as follows:

[0020] The embodiments of the present invention provide a battery system, electric equipment, fast charging method and discharge method. By setting the battery modules, each battery module is independently set, and each battery module can be charged and discharged independently, thereby realizing simultaneous charging of each battery module; thus, compared with the battery system in the prior art, the charging time can be effectively shortened, thereby realizing fast charging; and, only simple modifications need to be made to the battery system so that each battery module can be charged independently, thereby reducing the voltage platform used during charging, thereby realizing fast charging of a low-voltage charging platform, and at the same time avoiding an increase in the production cost of the battery system. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic structural diagram of a battery system provided in an embodiment of the present invention;

[0022] Figure 2 A schematic structural diagram of another battery system provided in an embodiment of the present invention;

[0023] Figure 3 This is a schematic structural diagram of another battery system provided in an embodiment of the present invention;

[0024] Figure 4 This is a schematic structural diagram of a three-way structure provided in an embodiment of the present invention;

[0025] Figure 5 A schematic diagram of the connection relationship between the three-way structure and the liquid cooling module provided in an embodiment of the present invention;

[0026] Figure 6 A schematic structural diagram of an electric device provided in an embodiment of the present invention;

[0027] Figure 7 This is a flow chart of a discharge method provided in an embodiment of the present invention.

[0028] 10-single battery, 20-box, 21-frame, 22-base plate, 30-multi-channel structure, 31-main outlet, 32-branch outlet, 33-control valve, 100-battery system, 200-motor, m-battery management system, B, B1, B2, B3-battery modules, Y1, Y2-liquid cooling module. DETAILED DESCRIPTION

[0029] The following will be combined with the accompanying drawings to describe in detail the specific implementation methods of a battery system, electric equipment, fast charging method and discharge method provided by the embodiments of the present invention. It should be noted that the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0030] An embodiment of the present invention provides a battery system, such as Figure 1 and Figure 2 As shown, it includes: multiple (i.e., two or more) battery modules (such as B1, B2 and B3), each of which includes multiple (i.e., two or more) single batteries 10; wherein, for any battery module, the single batteries 10 included therein can be connected in series (such as Figure 1 and Figure 2 ), or a parallel connection (not shown), or a combination of a series connection and a parallel connection (not shown), which is not limited here;

[0031] The battery module has a total positive output terminal and a total negative output terminal;

[0032] For any of the battery modules (taking B1 as an example): the total positive output terminal s11 and the total negative output terminal s12 are both electrically connected to the battery management system m;

[0033] The voltage difference between the total positive output terminal s11 and the total negative output terminal s12 of each battery module (taking B1 as an example) is not less than a preset value.

[0034] Among them, such as Figure 1As shown in the figure, three battery modules are shown. In order to distinguish the setting positions of the three battery modules, the three battery modules are respectively recorded as B1, B2 and B3. The total positive output terminal of the battery module B1 is represented by s11, the total negative output terminal of the battery module B1 is represented by s12, the total positive output terminal of the battery module B2 is represented by s21, the total negative output terminal of the battery module B2 is represented by s22, the total positive output terminal of the battery module B3 is represented by s31, and the total negative output terminal of the battery module B3 is represented by s32.

[0035] By arranging the battery modules, each battery module is independently arranged, and each battery module can be charged and discharged independently, thereby realizing simultaneous charging of each battery module; in this way, compared with the battery system in the prior art, the charging time can be effectively shortened, thereby realizing fast charging; and, only a simple modification of the battery system is required so that each battery module can be charged independently, thereby reducing the voltage platform used during charging, thereby realizing fast charging of the low-voltage charging platform, and at the same time avoiding an increase in the production cost of the battery system.

[0036] Moreover, because the voltage difference between the total positive output terminal and the total negative output terminal of each battery module is not less than a preset value, each battery module can independently provide driving capability. When the battery system is applied to an electric vehicle, each battery module can meet the power requirements of a single motor of the entire vehicle, thereby realizing independent operation of each battery module without the need to be restricted by each other.

[0037] Among them, the preset value can be set according to the power requirement of the single motor of the whole vehicle, and is not limited here.

[0038] To reiterate, each battery module can not only independently provide driving capability, but also independently charge and discharge; of course, each battery module can also provide driving capability and charge and discharge simultaneously, which can greatly reduce the charging time and achieve the fast charging purpose of the battery system. At the same time, it can also expand the application scope of the battery system, meet the needs of different application scenarios, and improve the flexibility of design.

[0039] It should be emphasized that in order to enable the battery system to achieve fast charging, if the voltage of the battery system (wherein the voltage can be understood as: the voltage difference between the total positive output terminal and the total negative output terminal of the battery pack) is 400V, in current technology, an 800V voltage platform can be used to charge the battery system (assuming that the charging time is recorded as time 1). At the same time, the battery system needs to be modified to a large extent to adapt to the high-voltage platform. These changes require more resources and also require improving the voltage resistance level of the material of the internal structure of the battery system. Therefore, there will be certain restrictions on material selection and the production cost of the battery system is increased.

[0040] In the solution provided in the embodiment of the present invention, only a simple modification is made to the battery system, that is, all the single cells in the current technology are connected in series and improved into multiple independently arranged battery modules, each battery module includes multiple single cells connected in series, and the total positive output terminal and the total negative output terminal of each battery module are electrically connected to the battery management system; therefore, the solution provided in the embodiment of the present invention causes relatively little modification to the battery system.

[0041] Furthermore, when charging the battery modules simultaneously in the solution provided by the embodiment of the present invention, only a 400V voltage platform is required to achieve fast charging, and the charging time can be less than time 1, further reducing the charging time, thereby achieving fast charging under a low voltage platform. Thus, in this solution, it is not necessary for the material of the internal structure of the battery system to have a high voltage rating. The selection of materials with a lower voltage rating can meet the requirements of fast charging, thereby expanding the range of material selection and avoiding an increase in production costs.

[0042] In addition, when charging using a higher voltage platform, the temperature of the battery system may be too high, which will accelerate the aging of the battery system and increase the risk of thermal runaway; when charging using a lower voltage platform, the temperature of the battery system can be prevented from being too high, which will prevent the accelerated aging of the battery system and the risk of thermal runaway, thereby improving the reliability, safety, and service life of the battery system.

[0043] It should also be noted that in the embodiment of the present invention, since the battery modules are independently arranged and do not affect each other, each battery module can work independently, and thus can be charged simultaneously or in sequence during charging; the specific setting can be made according to actual needs and is not limited here.

[0044] Optionally, in an embodiment of the present invention, the total positive output terminal of each battery module is electrically connected to the same interface of the battery management system, and the total negative output terminal of each battery module is electrically connected to a different interface of the battery management system; for example, Figure 2 As shown, the total positive output terminal s11 of the battery module B1 and the total positive output terminal s21 of the battery module B2 are both electrically connected to the first interface j1 of the battery management system m, the total negative output terminal s12 of the battery module B1 is electrically connected to the second interface j2 of the battery management system m, and the total negative output terminal s22 of the battery module B2 is electrically connected to the third interface j3 of the battery management system m;

[0045] Alternatively, the total negative output terminal of each battery module is electrically connected to the same interface of the battery management system, and the total positive output terminal of each battery module is electrically connected to different interfaces of the battery management system, which is not shown in the figure.

[0046] In this way, even if the battery management system has fewer interfaces, the connection relationship between each battery module and the battery management system can still be achieved. At the same time, it can also help reduce the production cost of the battery management system and expand the scope of application of the battery system.

[0047] Of course, optionally, in an embodiment of the present invention, the total positive output end of each battery module is electrically connected to a different interface of the battery management system m, and the total negative output end of each battery module is electrically connected to a different interface of the battery management system m, such as Figure 1 shown.

[0048] In this way, the control accuracy of the battery management system on each battery module can be improved, while mutual interference between the battery modules can be avoided.

[0049] Specifically, the connection method between each battery module and the battery management system can be set according to actual needs and is not limited here.

[0050] Optionally, in an embodiment of the present invention, Figure 2 As shown, two battery modules may be provided (eg, B1 and B2).

[0051] Of course, the number of battery modules is not limited to two, but can also be three (e.g. Figure 1 As shown), four (not shown) or more (not shown), can be set according to actual needs and are not limited here.

[0052] Optionally, in an embodiment of the present invention, the battery capacities of different battery modules are the same.

[0053] Furthermore, the types of the battery modules may be the same.

[0054] In this way, it is easy to control each battery module and simplify the control method.

[0055] Optionally, in an embodiment of the present invention, Figure 3 As shown, it also includes: a plurality of independently controlled liquid cooling modules (such as Y1 and Y2), each of the liquid cooling modules (such as Y1 and Y2) is correspondingly arranged with each of the battery modules (such as B1 and B2);

[0056] The liquid cooling module (taking Y1 as an example) is used for:

[0057] When the corresponding battery module B1 is in the working state, the corresponding battery module B1 is cooled; when the corresponding battery module B1 is not in the working state, the cooling process is stopped.

[0058] The working state of the battery module can be understood as the state in which the single cells in the battery module undergo electrochemical reactions.

[0059] In actual situations, when charging a battery system, the charging process may include: multiple charging stages, with a rest stage between each charging stage;

[0060] That is to say, the battery system can be charged for a period of time (recorded as a charging stage), then left to stand for a period of time (recorded as a resting stage), and then continued to charge for a period of time (recorded as another charging stage), and then left to stand for a period of time (recorded as another resting stage), and so on, until charging is completed.

[0061] Therefore, the working state may include: a charging stage and a rest stage between two charging stages. Of course, the working state may also include: a discharging stage.

[0062] In this way, by setting up the liquid cooling module, the matching of the liquid cooling module and the battery module can be achieved, so that when a battery module is in working state and other battery modules are not in working state, the liquid cooling module corresponding to the battery module in working state is started and cooling is performed, while other liquid cooling modules will not be cooled to ensure the maximum liquid cooling heat dissipation capacity and dissipate heat for the battery module, thereby effectively improving the heat dissipation efficiency.

[0063] In a specific implementation, in an embodiment of the present invention, the correspondence between the liquid cooling module and the battery module can be set as follows:

[0064] 1. One-to-one;

[0065] Optionally, in an embodiment of the present invention, Figure 3 As shown, each of the liquid cooling modules (such as Y1 and Y2) is provided in a one-to-one correspondence with each of the battery modules (such as B1 and B2);

[0066] That is to say, each liquid cooling module corresponds to a battery module, so that one liquid cooling module can cool one battery module. While improving the heat dissipation efficiency, it can also avoid cooling liquid cooling modules that do not need cooling treatment, thereby reducing power consumption and saving resources.

[0067] Optionally, in an embodiment of the present invention, Figure 3 As shown, the battery system further includes: a box 20, in which the battery modules (such as B1 and B2) are located. The box 20 includes: a frame 21 and a bottom plate 22, and the liquid cooling modules (such as Y1 and Y2) are arranged on the bottom plate 22 (that is, they can be arranged inside or outside the bottom plate 22); Figure 3 The liquid cooling module is located inside the base plate 22, and Y1 and Y2 represent two liquid cooling modules located inside the base plate 22 respectively;

[0068] The battery module has a first orthographic projection on the bottom plate surface, and the liquid cooling module has a second orthographic projection on the bottom plate surface. The area of ​​the first orthographic projection is less than or equal to the area of ​​the second orthographic projection.

[0069] That is, in a direction parallel to the bottom plate surface, the area of ​​the liquid cooling module may be greater than or equal to the area of ​​the battery module.

[0070] In this way, it is possible to avoid the situation where a part of the battery module cannot be cooled due to the larger area of ​​the battery module and the smaller area of ​​the liquid cooling module, thereby achieving effective heat dissipation of the battery module.

[0071] Of course, optionally, in an embodiment of the present invention, when the box body includes a box cover, the liquid cooling module can also be arranged at the box cover (that is, it can be arranged inside or outside the box cover).

[0072] The location of the liquid cooling module can be set according to actual needs and is not limited here.

[0073] 2. One-to-many;

[0074] Optionally, in an embodiment of the present invention, multiple liquid cooling modules correspond to one battery module;

[0075] The area of ​​the first orthographic projection may be larger than the area of ​​the second orthographic projection.

[0076] That is, in a direction parallel to the bottom plate surface, the area of ​​the liquid cooling module may be smaller than the area of ​​the battery module.

[0077] In this way, by configuring multiple liquid cooling modules to correspond to one battery module, even if the battery module area is larger than the liquid cooling module area, it is still possible to avoid the situation where part of the battery module cannot be cooled, thereby achieving effective heat dissipation of the battery module.

[0078] Optionally, in an embodiment of the present invention, Figure 4 As shown, it also includes: a multi-way structure 30, the multi-way structure 30 includes: a main outlet 31, N branch outlets 32, and N control valves 33, N is the number of settings of the liquid cooling module, each control valve 33 is set in a one-to-one correspondence with each branch outlet 32, and the control valve 33 is used to control the opening and closing of the corresponding branch outlet 32;

[0079] like Figure 5 As shown, each of the liquid cooling modules (taking Y1 as an example) includes: a liquid inlet kr and a liquid outlet kc; each of the branch outlets ( Figure 5The two outlets on the upper side of the multi-channel structure 30 are not marked with symbols, but may represent two branch outlets) and are correspondingly connected to the liquid inlet kr of each of the liquid cooling modules Y1, or each of the branch outlets is correspondingly connected to the liquid outlet of each of the liquid cooling modules (not shown).

[0080] When each of the branch outlets is correspondingly connected to the liquid inlet of each of the liquid cooling modules, a liquid outlet and inlet are respectively provided in the frame of the box body, which are connected to the liquid outlet and the total outlet of the multi-pass structure. At this time, the number of inlets set in the frame can be reduced, avoiding the risk of leakage and poor sealing effect when the number of inlets set is large, thereby improving the reliability of the battery system.

[0081] Similarly, when each of the branch outlets is correspondingly connected to the liquid outlet of each of the liquid cooling modules, a liquid inlet and outlet are provided in the frame of the box body, which are respectively connected to the liquid inlet and the total outlet of the multi-pass structure. At this time, the number of outlets set in the frame can be reduced, avoiding the risk of leakage and poor sealing effect when the number of outlets set is large, thereby improving the reliability of the battery system.

[0082] Furthermore, it should be pointed out that Figure 5 Taking the figure as an example, if the liquid cooling module Y1 needs to be cooled and the liquid cooling module Y2 does not need to be cooled, the control valve 33 on the left side of the figure is opened and the control valve 33 on the right side of the figure is closed, so that: the liquid used for cooling can enter from the total outlet of the multi-way structure 30 (that is, the outlet below the multi-way structure 30 in the figure), and enter the liquid cooling module Y1 through the outlet on the upper left side of the multi-way structure 30 in the figure, flow in the direction indicated by the dotted arrow, and finally flow out from the liquid outlet kc of the liquid cooling module Y1. Through the flow of liquid, heat exchange is carried out with the original liquid in the liquid cooling module Y1, thereby realizing the heat dissipation function.

[0083] Based on the same inventive concept, an embodiment of the present invention provides an electric device, such as Figure 6 As shown, it includes: multiple motors 200, a battery management system m, and the above-mentioned battery system 100 provided in an embodiment of the present invention;

[0084] The number of the motors 200 is less than or equal to the number of the battery modules B.

[0085] The motor 200 is configured to operate under the control of the battery management system m and driven by at least one of the battery modules B.

[0086] When the number of motors is less than the number of battery modules, the number of motors may be set as follows:

[0087] For some motors, one motor is driven by one battery module; for the rest of the motors, one motor is driven by multiple battery modules; for example, taking two motors and three battery modules as an example, two battery modules can drive one motor, and the other battery module drives the other motor.

[0088] Alternatively, each motor is driven by multiple battery modules; for example, taking two motors and four battery modules as an example, two battery modules can drive one motor, and the other two battery modules can drive another motor.

[0089] When the number of motors is equal to the number of battery modules, it can be configured as follows: one motor is driven by one battery module; for example, Figure 6 As shown, the upper battery module B shown in the figure can be used to drive the motor 200 on the left side of the figure, and the lower battery module B shown in the figure can be used to drive the motor 200 on the right side of the figure.

[0090] In this way, a multi-motor setting of the electric device can be realized. When a motor malfunctions and cannot work normally, the electric device can still work normally through other motors, thereby improving the reliability of the electric device.

[0091] Moreover, when each battery module can meet the power requirements of a single motor, if only one motor is provided, each battery module can alternately drive the motor, thereby providing higher power to the motor, so that the motor has higher operating performance during operation.

[0092] Optionally, in an embodiment of the present invention, each motor has a positive input terminal and a negative input terminal, the positive input terminal of each motor can be electrically connected to the same interface of the battery management system, and the negative input terminal of each motor can be electrically connected to different interfaces of the battery management system; for example, Figure 6 As shown, the positive input terminals of the two motors 200 are electrically connected to the same interface HV+ of the battery management system m, and the negative input terminals of the two motors 200 are electrically connected to the interface HV1- and the interface HV2- of the battery management system m respectively;

[0093] Alternatively, the negative input terminals of the motors may be electrically connected to the same interface of the battery management system, and the positive input terminals of the motors may be electrically connected to different interfaces of the battery management system (not shown).

[0094] Alternatively, the positive input terminal of each motor can be electrically connected to a different interface of the battery management system, and the negative input terminal of each motor can be electrically connected to a different interface of the battery management system, which is not shown in the figure.

[0095] The connection method between each motor and the battery management system can be set according to actual needs and is not limited here.

[0096] Optionally, in the embodiment of the present invention, the number of motors is not limited to Figure 6 As shown in the two, the number of motors can be set according to the number of battery modules to meet the needs of different application scenarios while improving design flexibility.

[0097] Optionally, in an embodiment of the present invention, the battery system may be: a battery module or a battery pack, in which case the battery system does not include a battery management system;

[0098] Alternatively, the battery system may also include a battery, in which case the battery system includes a battery management system.

[0099] Based on the same inventive concept, an embodiment of the present invention provides a fast charging method, including:

[0100] Using a voltage platform lower than a preset voltage, fast charging each battery module in the battery system provided by an embodiment of the present invention;

[0101] The preset voltage is a voltage used when fast charging is performed on the battery modules connected in series after the battery modules are connected in series.

[0102] For example, if the battery modules are connected in series and the voltage platform used for fast charging is 800V, then the voltage platform used in this solution is lower than 800V, which means that fast charging can still be achieved without upgrading to an 800V voltage platform.

[0103] In this way, since each battery module can be charged independently, the voltage platform used during charging can be lowered, thereby achieving fast charging on a low-voltage charging platform.

[0104] Optionally, in the embodiment of the present invention, when charging the battery modules, it can be configured as: simultaneous charging or sequential charging according to actual needs to meet the needs of different application scenarios.

[0105] For example, in some scenarios, if the time provided for charging is short, a simultaneous charging method can be adopted to charge each battery module at the same time, so that all batteries can be fully charged in a shorter time.

[0106] Alternatively, in some scenarios, it is not necessary to charge all battery modules, but only some of the battery modules. Since each battery module is independently configured, the battery modules that need to be charged can be charged, while the battery modules that do not need to be charged will not be charged, thereby achieving the charging process of some battery modules.

[0107] Alternatively, in some scenarios, if the charging time required to fully charge each battery module is different, since each battery module is independently configured, each battery module can be charged in sequence, so that each battery module can be fully charged efficiently and accurately, while also achieving the purpose of fast charging.

[0108] Based on the same inventive concept, an embodiment of the present invention provides a discharge method, such as Figure 7 Shown, including:

[0109] S701. Control each battery module in the battery system provided by an embodiment of the present invention to discharge in sequence according to a preset discharge strategy.

[0110] S702. When the discharge of the last battery module is completed and it is determined that each battery module has residual power, continue to control each battery module to discharge in sequence according to the discharge strategy until each battery module has no residual power; wherein the discharge strategy includes: for any battery module, stopping the discharge when the released power reaches a preset power, and the preset power is less than the power of the battery module when it is fully charged.

[0111] For example, if two battery modules are provided, and the two battery modules are respectively recorded as battery module 1 and battery module 2, and the preset power is 20%, when battery module 1 and battery module 2 have not been over-discharged, assuming that the remaining power of battery module 1 and battery module 2 is 100%, then:

[0112] Step 1: Control battery module 1 to discharge. When the amount of electricity to be discharged reaches 20%, control battery module 1 to stop discharging. At this time, the remaining amount of electricity in battery module 1 is 80%. Control battery module 2 to discharge. When the amount of electricity to be discharged reaches 20%, control battery module 2 to stop discharging. At this time, the remaining amount of electricity in battery module 2 is 80%.

[0113] Step 2: Continue to control battery module 1 to discharge. When the amount of electricity to be released reaches 20%, control battery module 1 to stop discharging. At this time, the remaining amount of electricity in battery module 1 is 60%. Continue to control battery module 2 to discharge. When the amount of electricity to be released reaches 20%, control battery module 2 to stop discharging. At this time, the remaining amount of electricity in battery module 2 is 60%.

[0114] Step 3: When the remaining power of battery module 1 and battery module 2 are both 20%, continue to control battery module 1 to discharge. When the power to be released reaches 20%, control battery module 1 to stop discharging. At this time, the remaining power of battery module 1 is 0. Continue to control battery module 2 to discharge. When the power to be released reaches 20%, control battery module 2 to stop discharging. At this time, the remaining power of battery module 2 is 0.

[0115] Step 4: Since the remaining power of battery module 1 and battery module 2 is both 0, it is determined that battery module 1 and battery module 2 have no remaining power. At this time, battery module 1 and battery module 2 will no longer be controlled to discharge.

[0116] It should be noted that the preset power level is not limited to 20%, and can also be set to 10%, 30% or other values. The specific setting can be based on actual needs and is not limited here.

[0117] In this way, the battery modules can be discharged alternately, thereby continuously providing higher driving power to the motor, thereby improving the operating performance of the motor.

[0118] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A discharge method for a battery system, characterized in that: The battery system comprises: a plurality of battery modules, each comprising a plurality of single cells; the battery modules having a total positive output terminal and a total negative output terminal; for any of the battery modules, the total positive output terminal and the total negative output terminal are both electrically connected to a battery management system; the voltage difference between the total positive output terminal and the total negative output terminal of each battery module is not less than a preset value; the battery system further comprises: a plurality of independently controlled liquid cooling modules, each of the liquid cooling modules being provided in correspondence with each of the battery modules; the liquid cooling modules being configured to cool the corresponding battery modules when the corresponding battery modules are in an operating state, and to stop the cooling process when the corresponding battery modules are not in the operating state; The discharge method comprises: According to a preset discharge strategy, control each battery module in the battery system to discharge in sequence; After the last battery module has finished discharging and it is determined that all the battery modules have residual power, continue to control the battery modules to discharge in sequence according to the discharging strategy until all the battery modules have no residual power; The discharging strategy includes: for any of the battery modules, stopping discharging when the released power reaches a preset power, and the preset power is less than the power of the battery module when it is fully charged.

2. The discharge method according to claim 1, wherein: The total positive output terminal of each battery module is electrically connected to the same interface of the battery management system, and the total negative output terminal of each battery module is electrically connected to different interfaces of the battery management system; Alternatively, the total negative output terminal of each battery module is electrically connected to the same interface of the battery management system, and the total positive output terminal of each battery module is electrically connected to different interfaces of the battery management system.

3. The discharge method according to claim 1, wherein: There are two battery modules.

4. The discharge method according to claim 1, wherein: The battery capacities of the different battery modules are the same.

5. The discharge method according to claim 1, wherein: Each of the liquid cooling modules is arranged in one-to-one correspondence with each of the battery modules.

6. The discharge method according to claim 1, wherein: The battery system further includes a multi-way structure, comprising: a main outlet, N branch outlets, and N control valves, where N is the number of liquid cooling modules provided, each control valve being provided in a one-to-one correspondence with each branch outlet, and the control valve being used to control the opening and closing of the corresponding branch outlet; Each of the liquid cooling modules comprises: a liquid inlet and a liquid outlet; Each of the branch outlets is correspondingly connected to the liquid inlet of each of the liquid cooling modules, or each of the branch outlets is correspondingly connected to the liquid outlet of each of the liquid cooling modules.

7. The discharge method according to claim 1, wherein: When the battery system is charged, it also includes: Using a voltage platform lower than a preset voltage, fast charging each battery module in the battery system; The preset voltage is a voltage used when fast charging is performed on the battery modules connected in series after the battery modules are connected in series.

8. An electric device, characterized in that: include: A plurality of motors, a battery management system, and a battery system, wherein the battery system is discharged using the discharge method according to any one of claims 1 to 7; The number of the motors is less than or equal to the number of the battery modules; The motor is configured to operate under the control of the battery management system and driven by at least one of the battery modules.

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