Battery control method, battery system, power supply system, energy storage device, storage medium, and chip

Abstract

A battery control method, a battery system, a power supply system, an energy storage device, a storage medium, and a chip. The battery control method comprises: acquiring a first voltage and a second voltage, wherein the first voltage is the voltage of a first battery module, the second voltage is the voltage of a second battery module, the first battery module is electrically connected to the second battery module, and the capacity of the first battery module is different from that of the second battery module; and on the basis of the voltage difference between the first voltage and the second voltage, controlling the working mode of a direct current-direct current (DCDC) converter, wherein the DCDC converter is electrically connected to the second battery module, and the DCDC converter is used for controlling input or output power of the second battery module.

Description

Battery control method, battery system, power supply system, energy storage device, storage medium, and chip

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on July 31, 2023, with application number 202310956044.0 and application name “A battery control method, battery system, and power supply system”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of new energy technology, and specifically to a battery control method, a battery system, a power supply system, an energy storage device, a storage medium, and a chip. Background Art

[0003] Electrical devices typically ship with batteries installed and rely on them for energy. Over time, the battery system may need to be expanded, such as by adding new battery packs, due to the addition of high-power devices, aging of existing batteries, or the need for extended power supply.

[0004] However, expanding the battery system using battery packs of different capacities, especially using new battery packs with capacities significantly different from the original battery packs, can easily lead to lower battery system safety.

[0005] Summary of the Invention

[0006] The present application provides a battery control method, a battery system, a power supply system, an energy storage device, a storage medium, and a chip, which can improve the safety of battery system expansion.

[0007] In a first aspect, an embodiment of the present application provides a battery control method, the method comprising: obtaining a first voltage and a second voltage, wherein the first voltage is the voltage of a first battery module, the second voltage is the voltage of the second battery module, the first battery module and the second battery module are electrically connected, and the second battery module and the first battery module have different capacities; controlling an operating mode of a direct current-direct current (DCDC) converter according to a voltage difference between the first voltage and the second voltage, wherein the DCDC converter is electrically connected to the second battery module, and the DCDC converter is used to control the input power or output power of the second battery module.

[0008] In an embodiment of the present application, the input or output power of the second battery module can be controlled by DCDC converter software according to the voltage difference between the first battery module and the second battery module, so that the second battery module with a different capacity from the first battery module can be incorporated into the battery system to achieve capacity expansion of the battery system, making battery system expansion more convenient and safer.

[0009] In some embodiments, controlling the operating mode of the DCDC converter based on the voltage difference between the first voltage and the second voltage includes: if the second voltage is less than the first voltage, the voltage difference between the first voltage and the second voltage is greater than or equal to a first preset voltage threshold, and in the charging state, controlling the DCDC converter to operate in Buck mode, wherein the Buck mode is used to step down the input voltage of the second battery module to a third voltage, and the difference between the third voltage and the second voltage is less than or equal to a first threshold.

[0010] In some embodiments, controlling the operating mode of the DCDC converter based on the voltage difference between the first voltage and the second voltage includes: if the second voltage is less than the first voltage, the voltage difference between the first voltage and the second voltage is greater than or equal to a first preset voltage threshold, and in a discharge state, controlling the DCDC converter to operate in a Boost mode, wherein the Boost mode is used to boost the output voltage of the second battery module to a fourth voltage, and the difference between the fourth voltage and the first voltage is less than or equal to a second threshold.

[0011] In some embodiments, controlling the operating mode of the DCDC converter based on the voltage difference between the first voltage and the second voltage includes: if the second voltage is greater than the first voltage, the voltage difference between the first voltage and the second voltage is greater than or equal to a second preset voltage threshold, and in the charging state, controlling the DCDC to operate in a Boost mode, wherein the Boost mode is used to boost the input voltage of the second battery module to a fifth voltage, and the difference between the fifth voltage and the second voltage is less than or equal to a third threshold.

[0012] In some embodiments, controlling the operating mode of the DCDC converter based on the voltage difference between the first voltage and the second voltage includes: if the second voltage is greater than the first voltage, the voltage difference between the first voltage and the second voltage is greater than or equal to a second preset voltage threshold, and in the discharge state, controlling the DCDC converter to operate in Buck mode, wherein the Buck mode is used to step down the output voltage of the second battery module to a sixth voltage, and the difference between the sixth voltage and the first voltage is less than or equal to a fourth threshold.

[0013] In some embodiments, controlling the operating mode of the DCDC converter based on the voltage difference between the first voltage and the second voltage includes: if the voltage difference between the first voltage and the second voltage is less than or equal to a third preset voltage threshold, and in the charging or discharging state, controlling the DCDC converter to operate in a pass-through mode, wherein the pass-through mode is suitable for not changing the input voltage or output voltage of the second battery module.

[0014] In a second aspect, an embodiment of the present application provides a battery system, including:

[0015] a first battery module, wherein a positive electrode of the first battery module is electrically connected to a positive terminal of a DC bus, and a negative electrode of the first battery module is electrically connected to a negative terminal of the DC bus;

[0016] a second battery module, the second battery module being electrically connected to the first battery module, the second battery module being electrically connected to the DC bus, and having a different capacity than the first battery module;

[0017] a DCDC converter, wherein a first end of the DCDC converter is electrically connected to the second battery module, a second end of the DCDC converter is electrically connected to the DC bus, and the DCDC converter is used to control the input or output power of the second battery module;

[0018] A control unit is configured to obtain a first voltage and a second voltage, and control an operating mode of a DCDC converter of the battery system according to a voltage difference between the first voltage and the second voltage, wherein the first voltage is a voltage of the first battery module and the second voltage is a voltage of the second battery module.

[0019] In an embodiment of the present application, the input or output power of the second battery module can be controlled by DCDC converter software according to the voltage difference between the first battery module and the second battery module, so that the second battery module with a different capacity from the first battery module can be incorporated into the battery system to achieve capacity expansion of the battery system, making battery system expansion more convenient and safer.

[0020] It should be understood that the specific content of the second aspect corresponds to the content of the first aspect, and the corresponding features and beneficial effects achieved in the second aspect can refer to the description of the first aspect. To avoid repetition, the detailed description is appropriately omitted here.

[0021] In some embodiments, the control unit is configured to control an operating mode of a DCDC converter of the battery system according to a voltage difference between the first voltage and the second voltage, specifically for:

[0022] If the second voltage is lower than the first voltage, the voltage difference between the first voltage and the second voltage is greater than or equal to a first preset voltage threshold, and the battery system is in a charging state, the DCDC converter is controlled to operate in Buck mode, wherein the Buck mode is used to step down the input voltage of the second battery module to a third voltage, and the difference between the third voltage and the second voltage is less than or equal to a first threshold.

[0023] In some embodiments, the control unit is configured to control an operating mode of a DCDC converter of the battery system according to a voltage difference between the first voltage and the second voltage, specifically for:

[0024] If the second voltage is lower than the first voltage, the voltage difference between the first voltage and the second voltage is greater than or equal to a first preset voltage threshold, and the battery system is in a discharging state, the DCDC converter is controlled to operate in a Boost mode, wherein the Boost mode is used to boost the output voltage of the second battery module to a fourth voltage, and the difference between the fourth voltage and the first voltage is less than or equal to a second threshold.

[0025] In some embodiments, the control unit is configured to control an operating mode of a DCDC converter of the battery system according to a voltage difference between the first voltage and the second voltage, specifically for:

[0026] If the second voltage is greater than the first voltage, the voltage difference between the first voltage and the second voltage is greater than or equal to a second preset voltage threshold, and the battery system is in a charging state, the DCDC is controlled to operate in a Boost mode, wherein the Boost mode is used to boost the input voltage of the second battery module to a fifth voltage, and the difference between the fifth voltage and the second voltage is less than or equal to a third threshold.

[0027] In some embodiments, the control unit is configured to control an operating mode of a DCDC converter of the battery system according to a voltage difference between the first voltage and the second voltage, specifically for:

[0028] If the second voltage is greater than the first voltage, the voltage difference between the first voltage and the second voltage is greater than or equal to a second preset voltage threshold, and the battery system is in a discharging state, the DCDC converter is controlled to operate in Buck mode, wherein the Buck mode is used to step down the output voltage of the second battery module to a sixth voltage, and the difference between the sixth voltage and the first voltage is less than or equal to a fourth threshold.

[0029] In some embodiments, the control unit is configured to control an operating mode of a DCDC converter of the battery system according to a voltage difference between the first voltage and the second voltage, specifically for:

[0030] If the voltage difference between the first voltage and the second voltage is less than or equal to a third preset voltage threshold, and the battery system is in a charging or discharging state, the DCDC converter is controlled to operate in a pass-through mode, wherein the pass-through mode is suitable for not changing the input voltage or output voltage of the second battery module.

[0031] In some embodiments, the DCDC converter includes a first switch, a second switch, a third switch, and a fourth switch, wherein the first end of the DCDC converter is electrically connected to the first end of the first switch and the first end of the second switch, respectively, the second end of the DCDC converter is electrically connected to the first end of the third switch and the first end of the fourth switch, respectively, the second end of the first switch is electrically connected to the first end of the second switch, the second end of the second switch is electrically connected to the first end of the third switch, and the second end of the third switch is electrically connected to the second end of the fourth switch.

[0032] In some embodiments, the control unit is further configured to control the first switch to be normally closed, the second switch to be normally open, and the third switch and the fourth switch to be complementarily turned on with a first duty cycle.

[0033] In some embodiments, the control unit is further configured to control the third switch to be normally open and the fourth switch to be normally closed, and to control the first switch and the second switch to be complementarily turned on with a second duty cycle.

[0034] In a third aspect, an embodiment of the present application provides a power supply system, comprising an electrical device and the battery system according to the second aspect or any one of the embodiments of the second aspect. The battery system is configured to implement the control method according to the first aspect or any one of the embodiments of the first aspect.

[0035] In some embodiments, the power supply system further includes a power conversion device configured to provide electrical energy in the battery system to the power-consuming device.

[0036] In a fourth aspect, an embodiment of the present application provides an energy storage device, characterized in that it includes the battery system described in the second aspect or any one embodiment of the second aspect.

[0037] In a fifth aspect, an embodiment of the present application provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the control method described in the first aspect or any one embodiment of the first aspect is implemented.

[0038] In a sixth aspect, an embodiment of the present application provides a computer program product, which includes a computer program. When the computer program is executed by a processor, it implements the control method described in the first aspect or any one embodiment of the first aspect.

[0039] In a seventh aspect, an embodiment of the present application provides a chip, which includes instructions, and when the instructions are executed, the control method described in the first aspect or any one embodiment of the first aspect is implemented. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the implementation methods of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the implementation methods or the description of the prior art. Obviously, the drawings described below are only some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0041] FIG1 is a flow chart of a battery control method provided in an embodiment of the present application.

[0042] FIG2 is a schematic structural diagram of a battery system provided in an embodiment of the present application.

[0043] FIG3 is a schematic structural diagram of a battery module provided in an embodiment of the present application.

[0044] FIG4 is a schematic structural diagram of a DCDC converter provided in an embodiment of the present application.

[0045] FIG5 is a schematic diagram of an operating mode of a DCDC converter provided in an embodiment of the present application.

[0046] FIG6 is a schematic diagram of an operating mode of a DCDC converter provided in another embodiment of the present application.

[0047] FIG7 is a schematic diagram of an operating mode of a DCDC converter provided in another embodiment of the present application.

[0048] FIG8 is a control flow chart of a DCDC converter provided in an embodiment of the present application. DETAILED DESCRIPTION

[0049] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0050] It should be noted that when a component is considered to be "connected" to another component assembly, it can be directly or indirectly connected to the other component.

[0051] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by those skilled in the art to which this application belongs. The terms used in this application and in the specification are only for describing specific embodiments and are not intended to limit this application. The term "and / or" as used in this application includes any and all combinations of one or more of the relevant listed items.

[0052] The following describes some embodiments of the present application in detail with reference to the accompanying drawings. In the absence of conflict, the following embodiments and features therein may be combined with each other.

[0053] An embodiment of the present application provides a battery control method. Please refer to FIG1 , which is a schematic flow chart of a battery control method provided by an embodiment of the present application. The method can be described using a control unit (e.g., an energy management control unit (EMCU)) as the execution entity. As shown in FIG1 , the battery control method can include at least the following operations.

[0054] S101 , obtaining a first voltage and a second voltage.

[0055] When the battery system needs to be expanded, a second battery module can be connected on the basis of the first battery module. The capacities of the first battery module and the second battery module are different. In one possible implementation, the first battery module may refer to an old battery module in the battery system, and the second battery module may refer to a new battery module in the battery system. In another possible implementation, the first battery module may refer to a small-capacity battery module in the battery system, and the second battery module may refer to a large-capacity battery module in the battery system. In this embodiment, the first battery module and the second battery module may be battery modules of the same model (type) or battery modules of different models. This application does not limit the capacity difference between the first battery module and the second battery module. The number of the first battery module and the second battery module may be one or more.

[0056] It can be understood that the battery module in the embodiment of the present application can be a battery module, a battery pack, a battery cluster, etc.

[0057] The first voltage can be understood as the rated voltage of the first battery module, and the second voltage can be understood as the rated voltage of the second battery module. Since the capacities of the first voltage module and the second voltage module are different, the rated voltages of the first voltage module and the second voltage module are also different.

[0058] In one possible implementation, when the second battery module is connected, the connection of the second battery module can be achieved by stepping up and down the DC-DC (direct current-direct current, DCDC) converter according to the voltage of the DC bus and the voltage of the second battery module. Specifically, the second battery module can be electrically connected to the DC bus through the DCDC converter. The DCDC converter can operate in constant current mode or direct mode, and the input current / voltage range of the DCDC converter meets the current / voltage conversion range of the battery module. The DCDC converter can operate in Buck constant current mode, Boost constant current mode, or direct mode.

[0059] Exemplarily, when the DC bus voltage is less than the voltage of the second battery module, the DCDC converter is controlled to operate in Buck constant current mode. When the DC bus voltage is greater than the voltage of the second battery module, the DCDC converter is controlled to operate in Boost constant current mode. When the DC bus voltage is close to the voltage of the second battery module, the DCDC converter is controlled to operate in Pass-through mode.

[0060] Therefore, the DCDC converter can realize the electrical connection between the first battery module and the second battery module under various operating conditions of the DC bus voltage. For example, whether the voltage of the second battery module is greater than or less than the voltage of the DC bus, the second battery module can be connected to the battery system, which can better balance the status of each battery module and make the battery system expansion more convenient and safe.

[0061] S102 : Control the operating mode of the DCDC converter according to the voltage difference between the first voltage and the second voltage.

[0062] The control unit can obtain battery information of the first battery module and the second battery module, which includes the state of charge (SOC, also called remaining power) of all battery strings, total voltage, output current and other information; the control unit can obtain circuit information of the DCDC converter, which includes DCDC operating status, operating mode, output current and other information; the control unit can also obtain scheduling information of the DCDC converter, which includes controlling DCDC start / stop according to DCDC operating conditions, giving the output target current of the DCDC converter when the DCDC converter is in constant voltage mode, and controlling the mode switching of the DCDC converter according to the DCDC mode switching conditions.

[0063] Specifically, controlling the operating mode of the DCDC converter according to the voltage difference between the first voltage and the second voltage includes: after obtaining the first voltage and the second voltage, the control unit may control the operating mode of the DCDC converter according to the voltage difference between the first voltage and the second voltage. Controlling the operating mode of the DCDC converter may be implemented in the following possible implementations.

[0064] In a first possible implementation, if the second voltage is less than the first voltage, and the voltage difference between the first voltage and the second voltage is greater than or equal to a first preset voltage threshold, when the battery system is in a charging state, the DCDC converter is controlled to operate in Buck mode, and the Buck mode is used to step down the input voltage of the second battery module to a third voltage, and the difference between the third voltage and the second voltage is less than or equal to a first threshold. It can be understood that when the battery system is in a charging state, the electric energy of the DC bus can charge the first battery module and the second battery module. If the second voltage is less than the first voltage, the voltage from the DC bus can be stepped down by the DCDC converter, that is, the input voltage of the second battery module can be converted to the third voltage to charge the second battery module, so as to achieve parallel current sharing of the first battery module and the second battery module.

[0065] A second possible implementation method is that if the second voltage is less than the first voltage, and the voltage difference between the first voltage and the second voltage is greater than or equal to a first preset voltage threshold: when the battery system is in a discharge state, the DCDC converter is controlled to operate in a Boost mode, and the Boost mode is used to boost the output voltage of the second battery module to a fourth voltage, and the difference between the fourth voltage and the first voltage is less than or equal to a second threshold. It can be understood that when the battery system is in a discharge state, the electrical energy in the first battery module and the second battery module can be discharged to the DC bus. If the second voltage is less than the first voltage, the output voltage of the second battery module can be boosted by the DCDC converter to a fourth voltage and transmitted to the DC bus, so as to achieve parallel current sharing of the first battery module and the second battery module.

[0066] A third possible implementation manner is that if the second voltage is greater than the first voltage, and the voltage difference between the first voltage and the second voltage is greater than or equal to a second preset voltage threshold: when the battery system is in a charging state, the DCDC is controlled to operate in a Boost mode, and the Boost mode is used to boost the input voltage of the second battery module to a fifth voltage, and the difference between the fifth voltage and the second voltage is less than or equal to a third threshold.

[0067] A fourth possible implementation manner is that if the second voltage is greater than the first voltage, and the voltage difference between the first voltage and the second voltage is greater than or equal to a second preset voltage threshold: when the battery system is in a discharging state, the DCDC converter is controlled to operate in Buck mode, and the Buck mode is used to step down the output voltage of the second battery module to a sixth voltage, and the difference between the sixth voltage and the first voltage is less than or equal to a fourth threshold.

[0068] A fifth possible implementation method may not limit the first voltage to be greater than or less than the second voltage. If the voltage difference is less than or equal to a third preset voltage threshold, that is, the first voltage and the second voltage are close, when the battery system is in a charging or discharging state, the DCDC converter is controlled to operate in a pass-through mode, and the pass-through module is suitable for not changing (for example, not boosting or lowering) the input or output voltage of the second battery module.

[0069] It can be understood that in the above different implementations, any two or more of the first threshold, the second threshold, the third threshold, and the fourth threshold can be the same threshold or different thresholds, which is explained here.

[0070] By controlling the operating mode of the DCDC converter through different strategies and taking the control unit as the execution body, the input or output power of the second battery module can be controlled by the DCDC converter software according to the voltage difference between the first battery module and the second battery module, thereby incorporating a second battery module with a different capacity from the first battery module into the battery system to achieve battery system expansion, making battery system expansion more convenient and safe.

[0071] Please refer to Figure 2, which is a schematic diagram of the structure of a battery system provided in an embodiment of the present application. As shown in Figure 2, the battery system may include a first battery module 201, a second battery module 202, a control unit 204, a DC-DC converter 203, and a DC bus. The positive electrode of the first battery module 201 is electrically connected to the positive terminal of the DC bus, and the negative electrode of the first battery module 201 is electrically connected to the negative terminal of the DC bus. The second battery module 202 is electrically connected to the first battery module 201, and the second battery module 202 is electrically connected to the DC bus. The second battery module 202 and the first battery module 201 have different capacities. The first terminal of the DC-DC converter 203 is electrically connected to the second battery module 202, and the second terminal of the DC-DC converter 203 is electrically connected to the DC bus. The DC-DC converter 203 is used to control the input power or output power of the second battery module 202.

[0072] The control unit 204 is used to implement the battery control method shown in FIG1 .

[0073] Specifically, the control unit 204 is configured to obtain a first voltage and a second voltage, and control an operating mode of the DCDC converter 203 according to a voltage difference between the first voltage and the second voltage.

[0074] After obtaining the first voltage and the second voltage, the control unit can control the operating mode of the DCDC converter according to the voltage difference between the first voltage and the second voltage. The control of the operating mode of the DCDC converter can be specifically implemented in the following possible implementations.

[0075] In a first possible implementation, if the second voltage is less than the first voltage, and the voltage difference between the first voltage and the second voltage is greater than or equal to a first preset voltage threshold, when the battery system is in a charging state, the DCDC converter is controlled to operate in Buck mode, and the Buck mode is used to step down the input voltage of the second battery module to a third voltage, and the difference between the third voltage and the second voltage is less than or equal to a first threshold. It can be understood that when the battery system is in a charging state, the electric energy of the DC bus can charge the first battery module and the second battery module. If the second voltage is less than the first voltage, the voltage from the DC bus can be stepped down by the DCDC converter to a third voltage, i.e., the input voltage of the second battery module, to charge the second battery module, so as to achieve parallel current sharing of the first battery module and the second battery module.

[0076] A second possible implementation method is that if the second voltage is less than the first voltage, and the voltage difference between the first voltage and the second voltage is greater than or equal to a first preset voltage threshold: when the battery system is in a discharge state, the DCDC converter is controlled to operate in a Boost mode, and the Boost mode is used to set the output voltage of the second voltage battery module to a fourth voltage, and the difference between the fourth voltage and the first voltage is less than or equal to a second threshold. It can be understood that when the battery system is in a discharge state, the electrical energy in the first battery module and the second battery module can be discharged to the DC bus. If the second voltage is less than the first voltage, the output voltage of the second battery module can be boosted by the DCDC converter to a fourth voltage and transmitted to the DC bus, so as to achieve parallel current sharing of the first battery module and the second battery module.

[0077] A third possible implementation manner is that if the second voltage is greater than the first voltage, and the voltage difference between the first voltage and the second voltage is greater than or equal to a second preset voltage threshold: when the battery system is in a charging state, the DCDC is controlled to operate in a Boost mode, and the Boost mode is used to boost the input voltage of the second battery module to a fifth voltage, and the difference between the fifth voltage and the second voltage is less than or equal to a third threshold.

[0078] A fourth possible implementation manner is that if the second voltage is greater than the first voltage, and the voltage difference between the first voltage and the second voltage is greater than or equal to a second preset voltage threshold: when the battery system is in a discharging state, the DCDC converter is controlled to operate in Buck mode, and the Buck mode is used to step down the output voltage of the second battery module to a sixth voltage, and the difference between the sixth voltage and the first voltage is less than or equal to a fourth threshold.

[0079] A fifth possible implementation method may not limit the first voltage to be greater than or less than the second voltage. If the voltage difference is less than or equal to a third preset voltage threshold, that is, the first voltage and the second voltage are close, when the battery system is in a charging or discharging state, the DCDC converter is controlled to operate in a pass-through mode, and the pass-through module is suitable for not changing (for example, not boosting or lowering) the input or output voltage of the second battery module.

[0080] In addition to operating in charging and discharging states, existing battery systems also need to operate in a static state. However, the battery system of the present application can control the input power or output power of the second battery module through a DCDC converter, so that the battery system only needs to operate in charging and discharging states, without the need for a static time slot to keep the states of the first battery module and the second battery module consistent, thereby improving the efficiency of capacity expansion.

[0081] Please refer to Figure 3, which is a structural diagram of a battery module provided in an embodiment of the present application. As shown in Figure 3, the first battery module 201 may include at least one battery management system (BMS) and at least one battery string. For example, the first battery module 201 includes a BMS (BMS11) and a battery string (battery string 11), and BMS11 is connected to battery string 11. For another example, the first battery module 201 includes a BMS (BMS11) and M battery strings (battery string 11 to battery string 1M), where M is a positive integer greater than or equal to 1, and BMS11 is respectively connected to battery string 11 to battery string 1M. The second battery module 202 may include at least one BMS and at least one battery string. For example, the second battery module 202 includes a BMS (BMS21) and a battery string (battery string 21), and BMS21 is connected to battery string 21. For another example, the second battery module 202 includes a BMS (BMS21) and N battery strings (battery string 21 to battery string 2N), where N is a positive integer greater than or equal to 1, and the BMS21 connects the battery strings 21 to 2N respectively.

[0082] In one possible implementation, the DCDC converter 203 can be connected to the DC bus independently of the second battery module 202, or the DCDC converter 203 can be included in the second battery module 202 and connected to the DC bus. The embodiment of the present application does not limit the connection method of the DCDC converter 203. In one possible implementation, the battery system may include at least one DCDC converter. For example, the battery system includes a DCDC converter 203, which is connected to the second battery module 202. For another example, the battery system includes multiple DCDC converters and multiple second battery modules, and each of the multiple DCDC converters is connected to the BMS and battery string in a corresponding second battery module.

[0083] The BMS can be used to manage battery strings. For example, the BMS can provide information such as the SOC of each battery string and the cell voltage (i.e., the voltage of a single battery module or a single cell). In one possible implementation, the control unit 204 is further configured to obtain the current of the first battery module and the second battery module, calculate the balancing current, i.e., the target current of the DCDC, and transmit it to the DCDC converter.

[0084] Specifically, when the battery system is discharging, the target current of the DCDC can be: I target =k*I sum *Soc%

[0085] Wherein, k represents the charge and discharge coefficient, which is used to adjust the output of the DCDC converter. n represents the total number of current battery strings (including the first battery module and the second battery module), and i represents the number of battery strings. Soc% = Soc j / Soc sum , m represents the number of strings operating in constant voltage mode, and j represents the number of the new battery string (the battery string in the second battery module).

[0086] It can be understood that when the battery system is charging, Soc j Replaced with 1-Soc j The embodiment of the present application can achieve better current sharing control at a low cost.

[0087] Please refer to Figure 4, which is a structural diagram of a DCDC converter provided in an embodiment of the present application. As shown in Figure 4, the DCDC converter includes a first switch Q1, a second switch Q2, a third switch Q3, and a fourth switch Q4. The left side of the DCDC converter can be used as the first end, and the right side of the DCDC converter can be used as the second end. The four switches can constitute a synchronous Buck circuit and a synchronous Boost circuit. Among them, the first end of the DCDC converter is electrically connected to the first end of the first switch Q1 and the first end of the second switch Q2, respectively. The second end of the DCDC converter is electrically connected to the first end of the third switch Q3 and the first end of the fourth switch Q4, respectively. The second end of the first switch Q1 is electrically connected to the first end of the second switch Q2, the second end of the second switch Q2 is electrically connected to the first end of the third switch Q3, and the second end of the third switch Q3 is electrically connected to the second end of the fourth switch Q4.

[0088] Based on the circuit structure of the above embodiment, when the control unit controls the DCDC converter to operate in Boost mode, as shown in FIG5 , the control unit may control the first switch Q1 to be normally closed and the second switch Q2 to be normally open, and the third switch Q3 and the fourth switch Q4 to be complementary turned on at a first duty cycle, thereby enabling the DCDC converter to operate in Boost mode. Similarly, based on the circuit structure of the above embodiment, when the control unit controls the DCDC converter to operate in Buck mode, as shown in FIG6 , the control unit may control the third switch Q3 to be normally open and the fourth switch Q4 to be normally closed, and the first switch Q1 and the second switch Q2 to be complementary turned on at a second duty cycle, thereby enabling the DCDC converter to operate in Buck mode. Similarly, based on the circuit structure of the above embodiment, when the control unit controls the DCDC converter to operate in Through mode, as shown in FIG7 , the control unit may control the first switch Q1 and the fourth switch Q4 to be normally closed, and the second switch Q2 and the third switch Q3 to be normally open, thereby enabling the DCDC converter to operate in Through mode.

[0089] It is understood that, taking Buck mode as an example, both the first switch Q1 and the fourth switch Q4 are high-side transistors, and a bootstrap boost drive method can generally be used. That is, for the fourth switch Q4, within a pulse width modulation (PWM) switching cycle, the third switch Q3 needs to have a specific on-time; otherwise, when the energy in the bootstrap capacitor of the fourth switch Q4 is depleted, the fourth switch Q4 will be turned off. In the embodiment of the present application, the third switch Q3 can be turned on with a very small duty cycle, while the fourth switch Q4 can be turned on with a nearly full duty cycle.

[0090] In a possible implementation, the DCDC converter may further include a first inductor L1, a first capacitor C1, and a second capacitor C2. The first inductor L1 may be used to store and release energy during operation of the main power circuit, the first capacitor C1 is an input voltage filter capacitor, and the second capacitor C2 is an output voltage filter capacitor. The four switches may be power tubes, metal-oxide-semiconductor field-effect transistors (MOS) tubes, or insulated gate bipolar transistors (IGBTs). It will be understood that the embodiment of the present application is only illustrated by taking four switches as an example, and the DCDC may also include more or fewer switches that can achieve the same functions as the present application. The present application does not limit the number of switches, capacitors, and inductors.

[0091] In one possible implementation, a DCDC converter may include a Buck-Boost main power circuit, a switch drive circuit, an input and output voltage and current signal sampling circuit, a digital signal processing (DSP) main controller control circuit, and peripheral circuits. The Buck-Boost main power circuit can be used to implement energy conversion between the system input and output; the switch drive circuit can be used to amplify the drive signal from the DSP main controller to drive the switch on and off; the signal sampling circuit can be used to convert the system input and output voltage and current signals into signals that can be read by the DSP main controller; and the DSP main controller circuit can be used to implement system input and output signal acquisition, control information reception and transmission, output status reporting, and Buck-Boost main power circuit switch control.

[0092] The loop structure may include two current loops, and the two loops may be in an inner and outer loop mode, with the output current being the outer loop and the inductor current being the inner loop.

[0093] Please refer to Figure 8, which is a control flow chart of a DCDC converter provided in an embodiment of the present application. As shown in Figure 8, the DCDC converter can adopt a current dual closed-loop control strategy. The DCDC converter can sample the main circuit output current and inductor current in real time, perform outer loop PI adjustment based on the difference between the target current and the actual current, and use the outer loop PI output as the inner loop current target. The duty cycle is calculated based on the inner loop PI output to drive the switch, ultimately achieving constant current output.

[0094] The control flow chart of the DCDC current can include an output current outer loop and an inductor current inner loop. The DCDC converter collects the output current I in real time. out , and the target current I of the DCDC converter calculated by the system unittarget Perform difference operation and calculate the error current as the input of the outer loop PI regulator, and limit the output result of the outer loop current PI regulator. The output current value after limiting will be used as the inner loop inductor current value IL target The DCDC converter collects the inductor current IL in real time. out , and the target inductor current value IL target The difference operation is performed to calculate the error value as the input of the inner loop PI regulator, and the output result of the inner loop current PI regulator is limited. The output value after limiting will be converted into PWM output signals, namely PWM_Q1, PWM_Q2, PWM_Q3, and PWM_Q4, and finally realize the closed-loop control output of the Buck-Boost main power circuit switch.

[0095] This embodiment adopts current double closed-loop PI control, which can achieve stable control of current and ensure small overshoot and good stability.

[0096] Embodiments of the present application also provide a power supply system. The power supply system includes an electrical device and the battery system described in any embodiment of the present application. The battery system is configured to provide electrical energy to the electrical device. The power supply system may include a data processing and logic control unit to implement the battery control method described in any of the above embodiments.

[0097] The present application also provides an energy storage device. The energy storage device includes the battery system described in any embodiment of the present application. The energy storage device can be used for power stations, grid-side storage, such as large containerized energy storage products, industrial and commercial storage, such as cabinet-type energy storage products, household energy storage products, or other types of energy storage products, which are not limited in this application.

[0098] An embodiment of the present application provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the battery control method in any of the above embodiments.

[0099] An embodiment of the present application provides a computer program product, which includes a computer program, and when the computer program is executed by a processor, implements the battery control method in any of the above embodiments.

[0100] An embodiment of the present application provides a chip, which includes instructions, and when the instructions are executed, implements the battery control method in any of the above embodiments.

[0101] In the description of the embodiments of the present application, it should be noted that the terms "first" and "second" are used to distinguish between identical or similar items having substantially the same functions. Those skilled in the art will understand that the terms "first" and "second" do not limit the quantity or order of execution, and do not necessarily define differences. Therefore, they should not be construed as limitations on the present application.

[0102] The above disclosure is only a preferred embodiment of the present application, and certainly cannot be used to limit the scope of rights of the present application. Ordinary technicians in this field can understand that all or part of the processes of the above embodiment and equivalent changes made in accordance with the claims of the present application are still within the scope covered by the present application.

Claims

1. A battery control method, characterized in that: The method comprises: Acquiring (S101) a first voltage and a second voltage, wherein the first voltage is a voltage of a first battery module, the second voltage is a voltage of a second battery module, the first battery module and the second battery module are electrically connected, and the second battery module and the first battery module have different capacities; According to the voltage difference between the first voltage and the second voltage, the operating mode of a direct current-to-direct current (DCDC) converter is controlled (S102), wherein the DCDC converter is electrically connected to the second battery module, and the DCDC converter is used to control the input power or output power of the second battery module.

2. The control method according to claim 1, characterized in that: The controlling the operating mode of the DCDC converter according to the voltage difference between the first voltage and the second voltage includes: If the second voltage is less than the first voltage, the voltage difference between the first voltage and the second voltage is greater than or equal to a first preset voltage threshold, and in the charging state, the DCDC converter is controlled to operate in Buck mode, wherein the Buck mode is used to step down the input voltage of the second battery module to a third voltage, and the difference between the third voltage and the second voltage is less than or equal to a first threshold.

3. The control method according to claim 1, characterized in that: The controlling the operating mode of the DCDC converter according to the voltage difference between the first voltage and the second voltage includes: If the second voltage is less than the first voltage, the voltage difference between the first voltage and the second voltage is greater than or equal to a first preset voltage threshold, and in the discharge state, the DCDC converter is controlled to operate in a Boost mode, wherein the Boost mode is used to boost the output voltage of the second battery module to a fourth voltage, and the difference between the fourth voltage and the first voltage is less than or equal to a second threshold.

4. The control method according to claim 1, characterized in that: The controlling the operating mode of the DCDC converter according to the voltage difference between the first voltage and the second voltage includes: If the second voltage is greater than the first voltage, the voltage difference between the first voltage and the second voltage is greater than or equal to a second preset voltage threshold, and in the charging state, the DCDC is controlled to operate in a Boost mode, wherein the Boost mode is used to boost the input voltage of the second battery module to a fifth voltage, and the difference between the fifth voltage and the second voltage is less than or equal to a third threshold.

5. The control method according to claim 1, characterized in that: The controlling the operating mode of the DCDC converter according to the voltage difference between the first voltage and the second voltage includes: If the second voltage is greater than the first voltage, the voltage difference between the first voltage and the second voltage is greater than or equal to a second preset voltage threshold, and in the discharge state, the DCDC converter is controlled to operate in Buck mode, wherein the Buck mode is used to step down the output voltage of the second battery module to a sixth voltage, and the difference between the sixth voltage and the first voltage is less than or equal to a fourth threshold.

6. The control method according to claim 1, characterized in that: The controlling the operating mode of the DCDC converter according to the voltage difference between the first voltage and the second voltage includes: If the voltage difference between the first voltage and the second voltage is less than or equal to a third preset voltage threshold, and in the charging or discharging state, the DCDC converter is controlled to operate in a direct-pass mode, wherein the direct-pass mode is suitable for not changing the input voltage or output voltage of the second battery module.

7. A battery system, characterized in that: include: a first battery module (201), wherein a positive electrode of the first battery module (201) is electrically connected to a positive terminal of a DC bus; and The negative electrode of the first battery module (201) is electrically connected to the negative terminal of the DC bus; a second battery module (202), the second battery module (202) being electrically connected to the first battery module (201), the second battery module (202) being electrically connected to the DC bus, and the second battery module (202) and the first battery module (201) having different capacities; a direct current-to-direct current (DCDC) converter (203), the DCDC converter (203) being electrically connected to the second battery module (202), the DCDC converter (203) being electrically connected to the DC bus, and the DCDC converter (203) being used to control the input power or output power of the second battery module (202); A control unit (204) is used to obtain a first voltage and a second voltage, and to control an operating mode of a DCDC converter (203) of the battery system according to a voltage difference between the first voltage and the second voltage, wherein the first voltage is a voltage of the first battery module (201), and the second voltage is a voltage of the second battery module (202).

8. The battery system according to claim 7, characterized in that: The control unit (204) is used to control the working mode of the DCDC converter (203) of the battery system according to the voltage difference between the first voltage and the second voltage, and is specifically used to: If the second voltage is lower than the first voltage, the voltage difference between the first voltage and the second voltage is greater than or equal to a first preset voltage threshold, and the battery system is in a charging state, the DCDC converter (203) is controlled to operate in a Buck mode, wherein the Buck mode is used to step down the input voltage of the second battery module (202) to a third voltage, and the difference between the third voltage and the second voltage is less than or equal to a first threshold.

9. The battery system according to claim 7, characterized in that: The control unit (204) is used to control the working mode of the DCDC converter (203) of the battery system according to the voltage difference between the first voltage and the second voltage, and is specifically used to: If the second voltage is lower than the first voltage, the voltage difference between the first voltage and the second voltage is greater than or equal to a first preset voltage threshold, and the battery system is in a discharging state, the DCDC converter (203) is controlled to operate in a Boost mode, wherein the Boost mode is used to boost the output voltage of the second battery module (202) to a fourth voltage, and the difference between the fourth voltage and the first voltage is less than or equal to a second threshold.

10. The battery system according to claim 7, characterized in that: The control unit (204) is used to control the working mode of the DCDC (203) of the battery system according to the voltage difference between the first voltage and the second voltage, and is specifically used to: if the second voltage is greater than the first voltage, the voltage difference between the first voltage and the second voltage is greater than or equal to a second preset voltage threshold, and the battery system is in a charging state, control the DCDC to work in a Boost mode, wherein the Boost mode is used to boost the input voltage of the second battery module (202) to a fifth voltage, and the difference between the fifth voltage and the second voltage is less than or equal to a third threshold.

11. The battery system according to claim 7, characterized in that: The control unit (204) is used to control the working mode of the DCDC converter (203) of the battery system according to the voltage difference between the first voltage and the second voltage, and is specifically used to: If the second voltage is greater than the first voltage, the voltage difference between the first voltage and the second voltage is greater than or equal to a second preset voltage threshold, and the battery system is in a discharging state, the DCDC converter (203) is controlled to operate in a Buck mode, wherein the Buck mode is used to step down the output voltage of the second battery module (202) to a sixth voltage, and the difference between the sixth voltage and the first voltage is less than or equal to a fourth threshold.

12. The battery system according to claim 7, characterized in that: The control unit (204) is used to control the working mode of the DCDC converter (203) of the battery system according to the voltage difference between the first voltage and the second voltage, and is specifically used to: If the voltage difference between the first voltage and the second voltage is less than or equal to a third preset voltage threshold, and the battery system In the charging or discharging state, the DCDC converter (203) is controlled to operate in a direct-flow mode, wherein the direct-flow mode is suitable for not changing the magnitude of the input voltage or the output voltage of the second battery module (202).

13. A power supply system, characterized in that: It comprises an electric device and a battery system as described in any one of claims 7 to 12, wherein the battery system is used to provide electric energy to the electric device.

14. An energy storage device, characterized in that: Comprising a battery system as described in any one of claims 7-12.

15. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores instructions, and when the instructions are executed by a processor, the battery control method according to any one of claims 1 to 6 is implemented.

16. A chip, characterized in that: The chip includes instructions, and when the instructions are executed, the battery control method according to any one of claims 1 to 6 is implemented.

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