Battery pack self-heating system and method

Abstract

The present application belongs to the field of batteries. Disclosed are a battery pack self-heating system and method. The system comprises: a target battery pack, which comprises a plurality of battery sub-packs and is used for providing electric energy; an energy storage module, which is used for storing the electric energy released by the target battery pack and charging the target battery pack by means of the stored electric energy; a charging and discharging switch group, which is used for controlling the opening and closing of a charging and discharging loop between the target battery pack and the energy storage module; a measurement module, which is used for measuring the voltage of each battery sub-pack, the voltage of the energy storage module and the battery temperature of the target battery pack; and a control module, which is connected to both the measurement module and the charging and discharging switch group, and is used for controlling the charging and discharging switch group on the basis of the voltages of the plurality of battery sub-packs, the voltage of the energy storage module and the battery temperature of the target battery pack, so as to realize the charging and discharging between the target battery pack and the energy storage module. In the present application, the self-heating of a target battery pack is realized by means of the charging and discharging between the target battery pack and an energy storage module, thereby improving the battery pack self-heating efficiency.

Description

Battery pack self-heating system and method

[0001] This application claims priority to Chinese patent application No. 202311451281.8 filed on November 2, 2023, entitled “Battery Pack Self-Heating System and Method,” the entire contents of which are incorporated herein by reference. Technical Field

[0002] The present application relates to the field of battery technology, and in particular to a battery pack self-heating system and method. Background Art

[0003] Batteries, as one of the primary energy sources, are widely used in the automotive sector. However, battery discharge characteristics and service life are affected by varying temperatures. Low temperatures, in particular, reduce the battery's internal conductivity and electrochemical reaction rate, leading to reduced charge and discharge power and durability. To address these issues, external or internal heating can be used to increase the battery's temperature when the battery is exposed to low temperatures to ensure efficient charge and discharge.

[0004] When raising the battery temperature through internal heating (self-heating), it is usually necessary to add a large number of electrical components. The current flows through these components, generating heat through the current and the internal resistance of the components, thus achieving self-heating of the battery pack. However, due to the complex internal structure of the battery pack, the addition of a large number of electrical components not only increases costs but also reduces the stability of the battery pack during charging and discharging, increasing safety risks during battery use. Therefore, the efficiency of current battery pack self-heating methods is poor.

[0005] Summary of the Invention

[0006] This application provides a battery pack self-heating system and method, which can improve the efficiency of battery pack self-heating. The technical solution is as follows:

[0007] In one aspect, a battery pack self-heating system is provided, the system comprising:

[0008] a target battery pack, the target battery pack including a plurality of sub-battery packs for providing electrical energy;

[0009] an energy storage module, configured to store the electric energy released by the target battery pack and charge the target battery pack using the stored electric energy;

[0010] a charge-discharge switch group, connected between the target battery group and the energy storage module, for controlling the on-off of the charge-discharge circuit between the target battery group and the energy storage module;

[0011] a detection module, the detection module being connected to the target battery pack and the energy storage module respectively, and being configured to detect the voltage of each sub-battery pack in the plurality of sub-battery packs, the voltage of the energy storage module, and the battery temperature of the target battery pack;

[0012] a control module, wherein the control module is respectively connected to the detection module and the charge and discharge switch group, and is used to control the charge and discharge switch group based on the voltages of the multiple sub-battery groups, the voltage of the energy storage module, and the battery temperature of the target battery group to realize charging and discharging between the target battery group and the energy storage module.

[0013] Optionally, the charge and discharge switch group includes multiple switches, wherein the positive electrode of each sub-battery group is connected to one of the switches, and the other end of the switch is connected to one end of the energy storage module; the negative electrode of each sub-battery group is connected to one of the switches, and the other end of the switch is connected to the other end of the energy storage module; and one switch is connected between two adjacent sub-battery groups among the multiple sub-battery groups;

[0014] The control module is used to control the opening or closing of the multiple switches to control the on / off of the charge and discharge circuit between a single sub-battery group among the multiple sub-battery groups and the energy storage module, or to control the on / off of the charge and discharge circuit between the series path of the multiple sub-battery groups and the energy storage module.

[0015] In another aspect, a battery pack self-heating method applied to the above system is provided, the method comprising:

[0016] Acquiring the battery temperature of the target battery pack through the detection module;

[0017] When the battery temperature of the target battery pack is less than a first temperature threshold, obtaining, by the detection module, the voltages of the plurality of sub-battery packs included in the target battery pack and the voltage of the energy storage module;

[0018] Based on the voltages of the multiple sub-battery groups and the voltage of the energy storage module, controlling the charge and discharge switch group to achieve conduction of the charge and discharge circuit between the target battery group and the energy storage module;

[0019] During the charging and discharging process between the target battery pack and the energy storage module, monitoring the battery temperature of the target battery pack by the detection module;

[0020] When it is monitored that the battery temperature of the target battery group is greater than or equal to a second temperature threshold, the charge and discharge switch group is controlled to disconnect the charge and discharge circuit between the target battery group and the energy storage module, and the second temperature threshold is greater than the first temperature threshold.

[0021] Optionally, controlling the charge and discharge switch group based on the voltages of the multiple sub-battery groups and the voltage of the energy storage module to achieve conduction of the charge and discharge circuit between the target battery group and the energy storage module includes:

[0022] determining a first sub-battery group having the largest voltage from among the plurality of sub-battery groups;

[0023] When the voltage of the first sub-battery group is greater than the voltage of the energy storage module, and the difference between the voltage of the first sub-battery group and the voltage of the energy storage module is greater than a first voltage threshold, controlling the charge and discharge switch group to cyclically charge the energy storage module through the multiple sub-battery groups;

[0024] When the absolute value of the difference between the voltage of the first sub-battery group and the voltage of the energy storage module is less than or equal to the first voltage threshold, controlling the charge and discharge switch group to charge the energy storage module through the multiple sub-battery groups connected in series;

[0025] When the voltage of the first sub-battery group is lower than the voltage of the energy storage module, and the difference between the voltage of the energy storage module and the voltage of the first sub-battery group is greater than the first voltage threshold, the charge and discharge switch group is controlled to charge the multiple sub-battery groups in a cycle through the energy storage module.

[0026] Optionally, the multiple sub-battery groups include two sub-battery groups; and controlling the charge and discharge switch group to cyclically charge the energy storage module through the multiple sub-battery groups includes:

[0027] Taking the first sub-battery group as a discharge sub-battery group, and determining a discharge loss voltage threshold corresponding to the discharge sub-battery group based on the voltages of the plurality of sub-battery groups;

[0028] Controlling the switches in the charge-discharge switch group connected to the positive and negative electrodes of the discharge sub-battery group to be closed, and the other switches to be opened, so as to charge the energy storage module through the discharge sub-battery group;

[0029] During the process of the discharge sub-battery pack charging the energy storage module, monitoring the battery temperature of the target battery pack, the temperature rise rate of the battery temperature of the target battery pack, and the discharge loss voltage of the discharge sub-battery pack by the detection module;

[0030] When it is monitored that the battery temperature of the target battery group is less than the second temperature threshold, the temperature rise rate of the battery temperature of the target battery group is greater than or equal to the rate threshold, and the discharge loss voltage of the discharge sub-battery group is greater than or equal to the discharge loss voltage threshold, another sub-battery group is used as the discharge sub-battery group, and the step of determining the discharge loss voltage threshold corresponding to the discharge sub-battery group based on the voltages of the multiple sub-battery groups is returned until the battery temperature of the target battery group is greater than or equal to the second temperature threshold, or the temperature rise rate of the battery temperature is less than the rate threshold.

[0031] Optionally, during the process of the discharge sub-battery pack charging the energy storage module, after monitoring the battery temperature of the target battery pack, the temperature rise rate of the battery temperature of the target battery pack, and the discharge loss voltage of the discharge sub-battery pack by the detection module, the method further includes:

[0032] When it is monitored that the battery temperature of the target battery group is lower than the second temperature threshold and the temperature rise rate of the battery temperature of the target battery group is lower than the rate threshold, the charge and discharge switch group is controlled to charge the energy storage module through the multiple sub-battery groups connected in series.

[0033] Optionally, controlling the charge and discharge switch group to charge the energy storage module through the multiple sub-battery groups connected in series includes:

[0034] Controlling switches on the series paths of the multiple sub-battery groups to be closed and other switches to be open, so as to charge the energy storage module through the multiple sub-battery groups connected in series;

[0035] During the process of the multiple sub-battery groups being connected in series to charge the energy storage module, monitoring the battery temperature of the target battery group and the temperature rise rate of the battery temperature of the target battery group by the detection module;

[0036] When it is monitored that the battery temperature of the target battery group is lower than the second temperature threshold and the temperature rise rate of the battery temperature of the target battery group is greater than or equal to the rate threshold, the energy storage module continues to be charged through the multiple sub-battery groups connected in series until the battery temperature of the target battery group is greater than or equal to the second temperature threshold, or the temperature rise rate of the battery temperature is lower than the rate threshold.

[0037] Optionally, in the process of charging the energy storage module by connecting the multiple sub-battery packs in series, after monitoring the battery temperature of the target battery pack and the temperature rise rate of the battery temperature of the target battery pack by the detection module, the method further includes:

[0038] When it is monitored that the battery temperature of the target battery group is lower than the second temperature threshold and the temperature rise rate of the battery temperature of the target battery group is lower than the rate threshold, the charge and discharge switch group is controlled to charge the multiple sub-battery groups through the energy storage module cycle.

[0039] Optionally, the multiple sub-battery groups include two sub-battery groups; and controlling the charge and discharge switch group to cyclically charge the multiple sub-battery groups through the energy storage module includes:

[0040] determining a second sub-battery group having the smallest voltage from among the plurality of sub-battery groups;

[0041] Using the second sub-battery group as a charging sub-battery group, and determining a charging rising voltage threshold corresponding to the charging sub-battery group based on the voltage of the energy storage module and the voltage of the charging sub-battery group;

[0042] Controlling the switches in the charge-discharge switch group connected to the positive and negative electrodes of the charging sub-battery group to be closed and the other switches to be opened, so as to charge the charging sub-battery group through the energy storage module;

[0043] During the process of the energy storage module charging the charging sub-battery group, the detection module monitors the battery temperature of the target battery group, the temperature rise rate of the battery temperature of the target battery group, and the charging rise voltage of the charging sub-battery group;

[0044] When it is monitored that the battery temperature of the target battery group is lower than the second temperature threshold, the temperature rise rate of the battery temperature of the target battery group is greater than or equal to the rate threshold, and the charging rise voltage of the charging sub-battery group is greater than or equal to the charging rise voltage threshold, another sub-battery group is used as the charging sub-battery group, and the step of determining the charging rise voltage threshold corresponding to the charging sub-battery group based on the voltage of the energy storage module and the voltage of the charging sub-battery group is returned until the battery temperature of the target battery group is greater than or equal to the second temperature threshold, or the temperature rise rate of the battery temperature is less than the rate threshold.

[0045] Optionally, during the process of the energy storage module charging the charging sub-battery group, after monitoring the battery temperature of the target battery group, the temperature rise rate of the battery temperature of the target battery group, and the charging rise voltage of the charging sub-battery group by the detection module, the method further includes:

[0046] When it is monitored that the battery temperature of the target battery group is lower than the second temperature threshold and the temperature rise rate of the battery temperature of the target battery group is lower than the rate threshold, the charge and discharge switch group is controlled to charge the energy storage module through the multiple sub-battery groups in a cycle.

[0047] Optionally, the method further comprises: determining a difference between a maximum voltage and a minimum voltage among the voltages of the plurality of sub-battery groups;

[0048] When the difference is greater than a second voltage threshold, determining a voltage change threshold based on the voltage of the energy storage module, the maximum voltage, and the minimum voltage;

[0049] Controlling the charge and discharge switch group to achieve conduction of the charge and discharge circuit between the target battery group and the energy storage module; monitoring the changing voltages of the multiple sub-battery groups through the detection module during the charge and discharge process between the target battery group and the energy storage module;

[0050] When it is monitored that the changed voltages of the multiple sub-battery groups are greater than or equal to the voltage change threshold, the charge and discharge switch group is controlled to disconnect the charge and discharge circuit between the target battery group and the energy storage module.

[0051] On the other hand, a vehicle is provided, comprising a memory and a controller, wherein the memory is used to store a computer program, and the controller is used to execute the computer program stored in the memory to implement the steps of the above-mentioned battery pack self-heating method.

[0052] On the other hand, a computer-readable storage medium is provided, wherein a computer program is stored in the storage medium, and when the computer program is executed by a controller, the steps of the battery pack self-heating method described above are implemented.

[0053] On the other hand, a computer program product comprising instructions is provided. When the instructions are executed on a computer, the computer is caused to execute the steps of the above-mentioned battery pack self-heating method.

[0054] The technical solution provided by this application can at least bring the following beneficial effects:

[0055] The voltage of the sub-battery group in the target battery group, the voltage of the energy storage module and the battery temperature of the target battery group are detected by the detection module, and whether self-heating is required is determined based on the battery temperature of the target battery group. When it is determined that the battery pack needs to be self-heated, the opening or closing of the charge and discharge switch group between the target battery group and the energy storage module is controlled based on the voltage of each sub-battery group and the voltage of the energy storage module, so as to realize the self-heating of the target battery group through charging and discharging between the target battery group and the energy storage module. The battery pack self-heating method provided by the present application does not require the addition of a large number of electrical components, saves costs, improves the stability of the target battery pack during the charging and discharging process, and improves the safety of the battery pack self-heating process. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0057] FIG1 is a schematic diagram of a battery pack self-heating system provided in an embodiment of the present application;

[0058] FIG2 is a schematic diagram of another battery pack self-heating system provided in an embodiment of the present application;

[0059] FIG3 is a flow chart of a battery pack self-heating method provided in an embodiment of the present application;

[0060] FIG4 is a flow chart of another battery pack self-heating method provided by an embodiment of the present application;

[0061] FIG5 is a flow chart of another battery pack self-heating method provided by an embodiment of the present application;

[0062] FIG6 is a flow chart of another battery pack self-heating method provided in an embodiment of the present application;

[0063] FIG7 is a flow chart of another battery pack self-heating method provided in an embodiment of the present application;

[0064] FIG8 is a flow chart of another battery pack self-heating method provided by an embodiment of the present application;

[0065] FIG9 is a schematic structural diagram of a vehicle provided in an embodiment of the present application. DETAILED DESCRIPTION

[0066] In order to make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the implementation methods of the present application will be further described in detail below with reference to the accompanying drawings.

[0067] Please refer to FIG1 , which is a schematic diagram of a battery pack self-heating system according to an exemplary embodiment. The battery pack self-heating system includes a target battery pack 101 , an energy storage module 102 , a charge and discharge switch group 103 , a detection module 104 , and a control module 105 .

[0068] The target battery group 101 includes multiple sub-battery groups for providing electrical energy. The energy storage module 102 is used to store the electrical energy released by the target battery group 101 and charge the target battery group 101 using the stored electrical energy. The charge-discharge switch group 103 is connected between the target battery group 101 and the energy storage module 102 and is used to control the on / off state of the charge-discharge circuit between the target battery group 101 and the energy storage module 102. The detection module 104 is connected to the target battery group 101 and the energy storage module 102 respectively and is used to detect the voltage of each of the multiple sub-battery groups, the voltage of the energy storage module 102, and the battery temperature of the target battery group 101. The control module 105 is connected to the detection module 104 and the charge-discharge switch group 103 respectively and is used to control the charge-discharge switch group 103 based on the voltages of the multiple sub-battery groups, the voltage of the energy storage module 102, and the battery temperature of the target battery group 101 to achieve charging and discharging between the target battery group 101 and the energy storage module 102.

[0069] The target battery pack 101 may be a power battery pack of a vehicle, including a plurality of batteries. The plurality of batteries are divided into a plurality of sub-battery packs.

[0070] The principle and number of sub-battery groups to be divided can be determined based on usage requirements. For example, the target battery group 101 can be divided into two sub-battery groups. For example, one side of the target battery group 101, such as the multiple sub-batteries on the left side of the target battery group 101, is determined as the first sub-battery group, and the other side of the target battery group, such as the multiple sub-batteries on the right side of the target battery group 101, is determined as the second sub-battery group.

[0071] It should be noted that, in the scenario of battery pack self-heating, the target battery pack 101 is mainly used to provide electrical energy to the energy storage module 102 so as to increase the battery temperature of the target battery pack 101 through the migration of electrons.

[0072] The energy storage module 102 may be any component capable of storing and releasing electrical energy. For example, the energy storage module 102 may be a single large-capacity capacitor to achieve electrical energy storage and release.

[0073] In some embodiments, the charge-discharge switch group 103 includes multiple switches, with the positive electrode of each sub-battery group being connected to a switch, the other end of which being connected to one end of the energy storage module 102; the negative electrode of each sub-battery group being connected to a switch, the other end of which being connected to the other end of the energy storage module 102; and a switch being connected between two adjacent sub-battery groups within the multiple sub-battery groups. The control module 105 is configured to control the opening or closing of the multiple switches to control the on / off of the charge-discharge circuit between a single sub-battery group within the multiple sub-battery groups and the energy storage module 102, or to control the on / off of the charge-discharge circuit between the series path of the multiple sub-battery groups and the energy storage module 102.

[0074] For example, as shown in Figure 2, the target battery group includes sub-battery group 11 and sub-battery group 12, and the charge-discharge switch group includes five switches, namely SP1, SP2, SP3, SP4, and SS1. The positive electrode of sub-battery group 11 is connected to one end of switch SP1, the positive electrode of sub-battery group 12 is connected to one end of switch SP3, and the other ends of switches SP1 and SP3 are connected to one end of energy storage module 102. The negative electrode of sub-battery group 11 is connected to one end of switch SP2, the negative electrode of sub-battery group 12 is connected to one end of switch SP4, and the other ends of switches SP2 and SP4 are connected to the other end of energy storage module 102. Switch SS1 is connected between the negative electrode of sub-battery group 11 and the positive electrode of sub-battery group 12.

[0075] It should be noted that the switch can be a high-frequency switch to achieve rapid on / off switching between sub-battery groups and between a sub-battery group and the energy storage module. The control module 105 controls the high-frequency switch to generate heat in the circuit, thereby promoting the increase of the battery temperature of the target battery group 101.

[0076] The detection module 104 may include a voltage sensor for detecting the cell voltage of each sub-battery group and the voltage of the energy storage module 101 ; the detection module 104 may also include a temperature sensor for detecting the battery temperature of the target battery group 101 .

[0077] The control module 105 can serve as the execution body of the battery pack self-heating method in the embodiment of the present application. The control module 105 can be a general-purpose CPU (Central Processing Unit), NP (Network Processor), microprocessor, or one or more integrated circuits for implementing the solution of the present application, such as ASIC (Application-Specific Integrated Circuit), PLD (Programmable Logic Device), or a combination thereof. The PLD can be a CPLD (Complex Programmable Logic Device), an FPGA (Field-Programmable Gate Array), a GAL (Generic Array Logic), or any combination thereof.

[0078] Those skilled in the art should understand that the above-mentioned target battery pack 101, energy storage module 102, charge and discharge switch group 103, detection module 104 and control module 105 are only examples. Other existing or future battery packs, energy storage modules, charge and discharge switch groups, detection modules or control modules that are applicable to the embodiments of the present application should also be included in the scope of protection of the embodiments of the present application and are included here by reference.

[0079] It should be noted that the implementation environment described in the embodiments of the present application is intended to more clearly illustrate the technical solutions of the embodiments of the present application, and does not constitute a limitation on the technical solutions provided in the embodiments of the present application. Ordinary technicians in this field can know that as the implementation environment evolves, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

[0080] Next, the battery pack self-heating method provided in the embodiment of the present application is explained in detail.

[0081] FIG3 is a flow chart of a battery pack self-heating method provided in an embodiment of the present application, which is applied to the above-mentioned control module. Referring to FIG3 , the method includes the following steps.

[0082] Step 301: Obtain the battery temperature of the target battery pack through a detection module.

[0083] In some embodiments, the detection module may obtain the battery temperature of the target battery pack in real time, and send the obtained battery temperature in real time to the control module.

[0084] The battery temperature of the target battery pack refers to the temperature of the battery cells of the target battery pack. For example, the detection module may include a temperature sensor connected to the battery cells of each sub-battery pack in the target battery pack to obtain the battery cell temperature of each sub-battery pack.

[0085] In some embodiments, the detection module may use the average temperature of multiple battery cell temperatures corresponding to multiple sub-battery groups as the battery temperature of the target battery group, or may obtain the battery temperature of the target battery group based on the battery cell temperature of each sub-battery group according to a preset temperature algorithm.

[0086] Step 302: When the battery temperature of the target battery pack is lower than a first temperature threshold, the detection module obtains the voltages of the multiple sub-battery packs and the voltage of the energy storage module included in the target battery pack.

[0087] When the battery temperature of the target battery pack is lower than the first temperature threshold, it indicates that the current battery temperature of the target battery pack is low, which will cause the charge and discharge power of the target battery pack to decrease. Therefore, it is necessary to start self-heating of the target battery pack (i.e., control the charge and discharge between the target battery pack and the energy storage module).

[0088] In some embodiments, the voltage of the sub-battery group refers to the cell voltage of the sub-battery group, and the voltage of the energy storage module refers to the cell voltage of the energy storage module. For example, the detection module may include a voltage sensor connected to the cell of each sub-battery group to obtain the cell voltage of each sub-battery group, and a voltage sensor connected to the cell of the energy storage module to obtain the cell voltage of the energy storage module.

[0089] In other embodiments, the voltage of a sub-battery group may also refer to the voltage across the sub-battery group, and the voltage of an energy storage module may also refer to the voltage across the energy storage module. For example, for any sub-battery group, the detection module may detect the voltage across the sub-battery group.

[0090] In some embodiments, before achieving self-heating of the target battery pack, it is also possible to determine whether the target battery pack has a safety risk based on the voltages of multiple sub-battery packs and the voltage of the energy storage module, so as to improve the safety of the subsequent self-heating process of the target battery pack.

[0091] In some embodiments, the method further includes: determining a difference between a maximum voltage and a minimum voltage among the voltages of the multiple sub-battery groups; determining a voltage change threshold based on the voltage, maximum voltage and minimum voltage of the energy storage module when the difference is greater than a second voltage threshold; controlling the charge and discharge switch group to achieve conduction of the charge and discharge circuit between the target battery group and the energy storage module; monitoring the change voltages of the multiple sub-battery groups through the detection module during the charge and discharge process between the target battery group and the energy storage module; and controlling the charge and discharge switch group to achieve disconnection of the charge and discharge circuit between the target battery group and the energy storage module when monitoring the change voltages of the multiple sub-battery groups to be greater than or equal to the voltage change threshold.

[0092] It should be noted that if the difference between the maximum and minimum voltages of multiple sub-battery groups is greater than the second voltage threshold, it indicates that the voltage difference between the sub-battery groups is large, resulting in a safety risk during the charging and discharging of the target battery group. In this case, the conduction of the charge and discharge circuit between the target battery group and the energy storage module can be controlled to reduce the maximum voltage in the sub-battery group or increase the minimum voltage in the sub-battery group, thereby reducing the voltage difference between the sub-battery groups and improving the safety of the target battery group.

[0093] In some embodiments, as shown in FIG4 , when the maximum voltage is greater than the voltage of the energy storage module, the charge and discharge switch group can be controlled to achieve conduction of the charge and discharge circuit between the energy storage module and the sub-battery group with the largest voltage, so that the energy storage module is charged through the sub-battery group with the largest voltage; when the maximum voltage is not greater than the voltage of the energy storage module, that is, the maximum voltage is less than or equal to the voltage of the energy storage module, the charge and discharge switch group can be controlled to achieve conduction of the charge and discharge circuit between the energy storage module and the sub-battery group with the smallest voltage, so that the sub-battery group with the smallest voltage is charged through the energy storage module.

[0094] In conjunction with Figure 2, let's take the example of a target battery group including two sub-battery groups, where the voltage of sub-battery group 11 is greater than the voltage of sub-battery group 12, and the difference between the voltages of sub-battery group 11 and sub-battery group 12 is greater than a second voltage threshold. If the voltage of sub-battery group 11 is greater than the voltage of the energy storage module, switches SP1 and SP2 are controlled to be closed, and switches SP3, SP4, and SS1 are controlled to be opened, and sub-battery group 11 charges the energy storage module. If the voltage of sub-battery group 11 is less than or equal to the voltage of the energy storage module, switches SP1, SP2, and SS1 are controlled to be opened, and switches SP3 and SP4 are controlled to be closed, and the energy storage module charges sub-battery group 12.

[0095] When the energy storage module is charged through the sub-battery group with the largest voltage, the voltage change threshold is the discharge loss voltage threshold. When the energy storage module is charged through the sub-battery group with the largest voltage, the voltage change threshold is the charge rise voltage threshold. When the energy storage module is charged through the sub-battery group with the largest voltage, and the discharge loss voltage of the sub-battery group with the largest voltage reaches the discharge loss voltage threshold, the charging circuit between the sub-battery group with the largest voltage and the energy storage module is disconnected by controlling the charge-discharge switch group. The discharge loss voltage of the sub-battery group with the largest voltage reaches the discharge loss voltage threshold, which can be understood as the discharge loss voltage being greater than or equal to the discharge loss voltage threshold. When the sub-battery group with the smallest voltage is charged through the energy storage module, and the charge rise voltage of the sub-battery group with the smallest voltage reaches the charge rise voltage threshold, the charging circuit between the energy storage module and the sub-battery group with the smallest voltage is disconnected by controlling the charge-discharge switch group. The charge rise voltage of the sub-battery group with the smallest voltage reaches the charge rise voltage threshold, which can be understood as the charge rise voltage being greater than or equal to the charge rise voltage threshold.

[0096] The discharge loss voltage threshold and the charge rise voltage threshold can be determined based on the voltage difference between the multiple sub-battery groups, such as △U = 0.8*(Umax-Umin), where Umax refers to the maximum voltage among the voltages of the multiple sub-battery groups, Umin refers to the minimum voltage among the voltages of the multiple sub-battery groups, and 0.8 refers to the correspondence between the discharge loss voltage threshold (or the charge rise voltage threshold) and the voltage difference between the sub-battery groups. The specific value can be determined in combination with actual usage requirements, such as 0.9, 0.85, etc.

[0097] In some embodiments, when the voltage of the energy storage module is less than the maximum voltage and greater than the minimum voltage, the discharge loss voltage threshold or the charge loss voltage threshold can be determined by the voltage difference between the maximum voltage and the voltage of the energy storage module, and the voltage difference between the voltage of the energy storage module and the minimum voltage.

[0098] For example, if the voltage of the energy storage module is less than the maximum voltage and greater than the minimum voltage, that is, the voltage of the energy storage module is between the maximum voltage and the minimum voltage, assuming that the voltage of the energy storage module is 3.5V, the maximum voltage among the voltages of the multiple sub-battery groups is 3.8V, and the minimum voltage is 3.4V, it can be obtained that the voltage difference between the maximum voltage and the voltage of the energy storage module is 0.3V, and the voltage difference between the voltage of the energy storage module and the minimum voltage is 0.1V, indicating that the voltage difference between the energy storage module and the sub-battery group with the largest voltage is larger than the voltage difference between the sub-battery group with the smallest voltage. Therefore, the energy storage module can be charged by the sub-battery group with the largest voltage to achieve the sub-battery group with the largest voltage. The voltage drops rapidly, that is, the voltage difference between the sub-battery groups decreases rapidly; assuming that the voltage of the energy storage module is 3.3V, the maximum voltage among the voltages of the multiple sub-battery groups is 3.4V, and the minimum voltage is 3.0V, it can be obtained that the voltage difference between the maximum voltage and the voltage of the energy storage module is 0.1V, and the voltage difference between the voltage of the energy storage module and the minimum voltage is 0.3V, indicating that the voltage difference between the energy storage module and the sub-battery group with the smallest voltage is larger than the voltage difference between the sub-battery group with the largest voltage. Therefore, the sub-battery group with the smallest voltage can be charged by the energy storage module to achieve a rapid increase in the voltage of the sub-battery group with the smallest voltage, that is, a rapid decrease in the voltage difference between the sub-battery groups.

[0099] It should be noted that the main purpose of the above steps is to ensure that the voltage difference between the sub-battery groups is within an allowable range before the target battery group self-heats, if the target battery group needs to increase the battery temperature through self-heating. For example, the voltage difference between the sub-battery groups must be less than or equal to the second voltage threshold. If the voltage difference between the sub-battery groups is large, it is necessary to first control the voltage difference between the sub-battery groups within the allowable range before charging and discharging the target battery group and the energy storage module.

[0100] In other embodiments, when the voltage difference between the sub-battery groups is large, it is not necessary to consider whether the battery temperature of the target battery group is less than the first temperature threshold. Instead, it is sufficient to ensure that the battery temperature of the target battery group is within a safe range, such as ensuring that the battery temperature of the target battery group is less than or equal to the third temperature threshold. In other words, when the voltage difference between the sub-battery groups is large, first consider reducing the voltage difference between the sub-battery groups, and then consider whether it is necessary to achieve self-heating of the target battery group through charging and discharging of the target battery group and the energy storage module.

[0101] Of course, in some other embodiments, after obtaining the voltages of the multiple sub-battery groups and the voltage of the energy storage module, self-heating of the target battery group can also be directly achieved, such as directly executing the following step 303, which is not limited in the embodiments of the present application.

[0102] Step 303: Based on the voltages of the multiple sub-battery groups and the voltage of the energy storage module, the charge and discharge switch group is controlled to achieve conduction of the charge and discharge circuit between the target battery group and the energy storage module.

[0103] In some embodiments, based on the voltages of the multiple sub-battery groups and the voltage of the energy storage module, the charge and discharge switch group can be controlled through the following steps (1)-(4) to achieve conduction of the charge and discharge circuit between the target battery group and the energy storage module.

[0104] (1) A first sub-battery group having the largest voltage is determined from among the plurality of sub-battery groups.

[0105] (2) When the voltage of the first sub-battery group is greater than the voltage of the energy storage module, and the difference between the voltage of the first sub-battery group and the voltage of the energy storage module is greater than a first voltage threshold, the charge and discharge switch group is controlled to charge the energy storage module through the plurality of sub-battery groups in a cycle.

[0106] If the voltage of the first sub-battery group is greater than the voltage of the energy storage module, and the difference between the voltage of the first sub-battery group and the voltage of the energy storage module is greater than the first voltage threshold, indicating that the voltage of the first sub-battery group is sufficiently greater than the voltage of the energy storage module, the current when the first sub-battery group charges the energy storage module will be relatively large, thereby ensuring that sufficient heat is generated during the charging and discharging process to achieve a faster temperature rise rate of the battery temperature of the target battery group, that is, the self-heating efficiency of the target battery group is relatively high. Therefore, when the voltage of the first sub-battery group is greater than the voltage of the energy storage module, and the voltage difference between the voltage of the first sub-battery group and the voltage of the energy storage module is greater than the first voltage threshold, charging the energy storage module by a single sub-battery group can achieve rapid temperature rise of the target battery group.

[0107] In some embodiments, as shown in FIG5 , where Umax refers to the maximum voltage among the voltages of the plurality of sub-battery groups, i.e., the voltage of the first sub-battery group, Uc refers to the voltage of the energy storage module, and d refers to the first voltage threshold, the plurality of sub-battery groups include two sub-battery groups. At this time, the first sub-battery group can be used as a discharge sub-battery group, and the discharge loss voltage threshold corresponding to the discharge sub-battery group is determined based on the voltages of the multiple sub-battery groups; the switches connected to the positive and negative poles of the discharge sub-battery group in the charge and discharge switch group are controlled to be closed, and the other switches are disconnected, so as to charge the energy storage module through the discharge sub-battery group; in the process of the discharge sub-battery group charging the energy storage module, the battery temperature of the target battery group, the temperature rise rate of the battery temperature of the target battery group, and the discharge loss voltage of the discharge sub-battery group are monitored by the detection module; when it is monitored that the battery temperature of the target battery group is less than the second temperature threshold, the temperature rise rate of the battery temperature of the target battery group is greater than or equal to the rate threshold, and the discharge loss voltage of the discharge sub-battery group is greater than or equal to the discharge loss voltage threshold, another sub-battery group is used as the discharge sub-battery group, and the step of determining the discharge loss voltage threshold corresponding to the discharge sub-battery group based on the voltages of the multiple sub-battery groups is returned until the battery temperature of the target battery group is greater than or equal to the second temperature threshold, or the temperature rise rate of the battery temperature is less than the rate threshold.

[0108] In the process of charging the energy storage module through the discharge sub-battery group, as the charging time increases, the voltage of the discharge sub-battery group will gradually decrease, that is, the discharge sub-battery group will produce voltage loss. In order to avoid the large voltage loss of the discharge sub-battery group, which leads to a large voltage difference between the sub-battery groups, thereby generating safety hazards during the self-heating process, in an embodiment of the present application, a discharge loss voltage threshold can be set based on the voltages of multiple sub-battery groups. When the loss voltage of a single discharge of the discharge sub-battery group is greater than or equal to the discharge loss voltage threshold, the sub-battery groups other than the currently discharged sub-battery group are used as discharge sub-battery groups to discharge the energy storage module, so as to realize the circulation of multiple sub-battery groups to charge the energy storage module, that is, the energy storage module is alternately charged by multiple sub-battery groups, so that multiple sub-battery groups can alternately generate voltage loss, so as to avoid the voltage difference between the sub-battery groups being large due to excessive single voltage loss of a certain sub-battery group when the sub-battery group charges the energy storage module, thereby generating safety hazards.

[0109] In some embodiments, the discharge loss voltage threshold may be determined by the following formula 1:

[0110] Where i refers to the i-th discharge cycle, i is a positive integer, Refers to the discharge loss voltage threshold corresponding to the discharge sub-battery pack during the i-th discharge, ΔU i Refers to the voltage difference between the sub-battery groups during the i-th discharge. For example, in the case where the plurality of sub-battery groups include two sub-battery groups, Refers to the voltage of the first sub-battery group during the i-th discharge, for example, it may be the voltage of the sub-battery group 11 in FIG. 2 during the i-th discharge, Refers to the voltage of the sub-battery group other than the first sub-battery group during the i-th discharge, such as the voltage of the sub-battery group 12 in Figure 2 during the i-th discharge.

[0111] It should be noted that 1.5 in Formula 1 refers to the corresponding relationship between the discharge loss voltage threshold and the voltage difference between the sub-battery packs. This corresponding relationship can be selected based on actual usage requirements, such as 1.3 times, 1.7 times, 2 times, etc.

[0112] The temperature rise rate of the target battery pack's battery temperature can be determined based on changes in the target battery pack's battery temperature. For example, the temperature rise rate of the target battery pack's battery temperature can be determined based on the temperature rise of the target battery pack's battery temperature within a target duration. The target duration can be flexibly determined based on actual usage requirements, such as within 2 seconds or within 1 second. The specific unit of the temperature rise rate can be selected based on actual usage requirements, such as degrees Celsius per second or degrees Fahrenheit per minute.

[0113] 2 , assuming that the target battery group includes a sub-battery group 11 and a sub-battery group 12, and the voltage of the sub-battery group 11 is greater than the voltage of the sub-battery group 12, when the sub-battery group 11 is used as a discharge sub-battery group, the switches SP1 and SP2 are controlled to be closed, and the switches SP3, SP4, and SS1 are controlled to be disconnected, and the sub-battery group 11 is used as a discharge sub-battery group to charge the energy storage module. If, until the discharge loss voltage of the sub-battery group 11 is greater than or equal to the discharge loss voltage threshold, the battery temperature of the target battery group is still less than the second temperature threshold, and the temperature rise rate of the battery temperature of the target battery group is still greater than or equal to the rate threshold, the switches SP1, SP2, and SS1 are controlled to be disconnected, and the switches SP3 and SP4 are controlled to be closed, and the sub-battery group 12 is used as a discharge sub-battery group to charge the energy storage module, so as to realize charging of the energy storage module based on multiple sub-battery groups in a cycle.

[0114] As can be seen from FIG5 , the cycle conditions for charging the energy storage module by cycling multiple sub-battery groups are: the battery temperature of the target battery group is less than the second temperature threshold, and the temperature rise rate of the battery temperature of the target battery group during the cycle is continuously greater than or equal to the rate threshold. Specifically, if the battery temperature of the target battery group is greater than or equal to the second temperature threshold, since the temperature of the target battery group has met the conditions, the self-heating of the target battery group can be terminated directly; if the temperature rise rate of the battery temperature of the target battery group is less than the rate threshold, since the target battery group can no longer be quickly heated by cycling multiple sub-battery groups for charging the energy storage module, the cycling multiple sub-battery groups for charging the energy storage module can be terminated.

[0115] In other words, when the temperature of the target battery pack is greater than or equal to the second temperature threshold, it indicates that the battery temperature of the target battery pack will no longer adversely affect the external charge and discharge power of the target battery pack, and thus the self-heating of the target battery pack can be terminated.

[0116] Also, as the sub-battery group circulates to continuously charge the energy storage module, the voltage of the sub-battery group will gradually decrease, and the voltage of the energy storage module will gradually increase, causing the voltage difference between the voltage of the sub-battery group and the voltage of the energy storage module to gradually decrease. At this time, due to the decrease in the voltage difference, the current in the charging circuit is weakened, which in turn causes the heat generation of the charging circuit to decrease, and the temperature rise rate of the battery temperature of the target battery group is reduced. When the temperature rise rate of the battery temperature of the target battery group is less than the rate threshold, it indicates that the voltage between the current sub-battery group and the energy storage module is already relatively close. If the self-heating of the target battery group continues to be achieved in this way, the temperature rise rate of the battery temperature of the target battery group will only become smaller and smaller. At this time, in order to improve the self-heating efficiency of the target battery group, it is necessary to adjust the charging and discharging method between the target battery group and the energy storage module.

[0117] In some embodiments, as shown in FIG5 , when it is detected that the battery temperature of the target battery group is less than a second temperature threshold and the temperature rise rate of the battery temperature of the target battery group is less than a rate threshold, the charge and discharge switch group can be controlled to charge the energy storage module through the multiple sub-battery groups connected in series. The details of charging the energy storage module through the multiple sub-battery groups connected in series will be described in detail in the following step (3) and will not be repeated here.

[0118] (3) When the absolute value of the difference between the voltage of the first sub-battery group and the voltage of the energy storage module is less than or equal to the first voltage threshold, the charge and discharge switch group is controlled to charge the energy storage module through the multiple sub-battery groups connected in series.

[0119] If the absolute value of the difference between the voltage of the first sub-battery group and the voltage of the energy storage module is less than or equal to the first voltage threshold, it indicates that the voltage of the first sub-battery group is close to the voltage of the energy storage module. In this case, whether the energy storage module is charged through the first sub-battery group or the first sub-battery group is charged through the energy storage module, due to the small voltage difference between the two, the current in the charging circuit is also small, and the heat generated during the charging and discharging process is small, resulting in a slower temperature rise rate of the battery in the target battery group. In other words, the self-heating efficiency of the target battery group is low, which cannot meet the requirement of rapid temperature rise of the target battery group.

[0120] In this case, considering the principle of battery series voltage boosting, multiple sub-battery groups can be connected in series so that the overall voltage of the target battery group is large enough compared to the voltage of the energy storage module, so that the current in the charge and discharge circuit is large enough to ensure that enough heat is generated during the charging and discharging process, so that the temperature rise rate of the battery of the target battery group is faster, that is, the self-heating efficiency of the target battery group is higher.

[0121] In some embodiments, as shown in FIG6 , the switches on the series paths of the multiple sub-battery groups can be controlled to be closed, and the other switches can be opened, so as to charge the energy storage module through the multiple sub-battery groups connected in series; in the process of charging the energy storage module through the multiple sub-battery groups connected in series, the battery temperature of the target battery group and the temperature rise rate of the battery temperature of the target battery group are monitored by the detection module; when it is monitored that the battery temperature of the target battery group is less than the second temperature threshold and the temperature rise rate of the battery temperature of the target battery group is greater than or equal to the rate threshold, the energy storage module continues to be charged through the multiple sub-battery groups connected in series until the battery temperature of the target battery group is greater than or equal to the second temperature threshold, or the temperature rise rate of the battery temperature is less than the rate threshold.

[0122] 2 , when the energy storage module is charged by connecting the sub-battery group 11 and the sub-battery group 12 in series, the switches SP1, SS1, and SP4 can be controlled to be closed, and the switches SP2, SS1, and SP2 can be controlled to be opened, thereby enabling the sub-battery group 11 and the sub-battery 12 to be connected in series to charge the energy storage module.

[0123] As can be seen from Figure 6, the execution conditions for charging the energy storage module by connecting multiple sub-battery groups in series are: the battery temperature of the target battery group is less than the second temperature threshold, and the temperature rise rate of the battery temperature of the target battery group during the cycle is continuously greater than or equal to the rate threshold. In particular, when the battery temperature of the target battery group is greater than or equal to the second temperature threshold, since the temperature of the target battery group has met the conditions, the self-heating of the target battery group can be directly terminated; when the temperature rise rate of the battery temperature of the target battery group is less than the rate threshold, since charging the energy storage module by connecting multiple sub-battery groups in series at this time can no longer quickly heat up the target battery group, the charging of the energy storage module by connecting multiple sub-battery groups in series can be terminated.

[0124] In other words, when the temperature of the target battery pack is greater than or equal to the second temperature threshold, it indicates that the battery temperature of the target battery pack will no longer adversely affect the external charge and discharge power of the target battery pack, and thus the self-heating of the target battery pack can be terminated.

[0125] Also, as the sub-battery groups are connected in series to continuously charge the energy storage module, the overall voltage of the sub-battery groups connected in series will gradually decrease, and the voltage of the energy storage module will gradually increase, causing the voltage difference between the overall voltage of the sub-battery groups connected in series and the voltage of the energy storage module to gradually decrease. At this time, due to the decrease in voltage difference, the current in the charging circuit is weakened, which in turn causes the heat generation of the charging circuit to decrease, and the temperature rise rate of the battery temperature of the target battery group is reduced. When the temperature rise rate of the battery temperature of the target battery group is less than the rate threshold, it indicates that the overall voltage of the sub-battery groups connected in series is already close to the voltage of the energy storage module. If the self-heating of the target battery group is continued in this way, the temperature rise rate of the battery temperature of the target battery group will only become smaller and smaller. At this time, in order to improve the self-heating efficiency of the target battery group, it is necessary to adjust the charging and discharging method between the target battery group and the energy storage module.

[0126] In some embodiments, as shown in FIG6 , when it is detected that the battery temperature of the target battery group is less than the second temperature threshold and the temperature rise rate of the battery temperature of the target battery group is less than the rate threshold, the charge and discharge switch group can be controlled to charge the multiple sub-battery groups through the energy storage module cycle. The details of charging the multiple sub-battery groups through the energy storage module cycle will be described in detail in the following step (4) and will not be repeated here.

[0127] (4) When the voltage of the first sub-battery group is lower than the voltage of the energy storage module, and the difference between the voltage of the energy storage module and the voltage of the first sub-battery group is greater than a first voltage threshold, the charge and discharge switch group is controlled to charge the multiple sub-battery groups through the energy storage module cycle.

[0128] In some embodiments, as shown in FIG. 7 , the plurality of sub-batteries includes two sub-batteries. At this time, a second sub-battery group with the smallest voltage can be determined from the multiple sub-battery groups; the second sub-battery group is used as the charging sub-battery group, and a charging rise voltage threshold corresponding to the charging sub-battery group is determined based on the voltage of the energy storage module and the voltage of the charging sub-battery group; the switches connected to the positive and negative poles of the charging sub-battery group in the charge-discharge switch group are controlled to be closed, and the other switches are controlled to be open, so that the charging sub-battery group is charged through the energy storage module; during the process of charging the charging sub-battery group by the energy storage module, the battery temperature of the target battery group, the temperature rise rate of the battery temperature of the target battery group, and the charging rise voltage of the charging sub-battery group are monitored by the detection module; if it is monitored that the battery temperature of the target battery group is less than a second temperature threshold, the temperature rise rate of the battery temperature of the target battery group is greater than or equal to the rate threshold, and the charging rise voltage of the charging sub-battery group is greater than or equal to the charging rise voltage threshold, another sub-battery group is used as the charging sub-battery group, and the step of determining the charging rise voltage threshold corresponding to the charging sub-battery group based on the voltage of the energy storage module and the voltage of the charging sub-battery group is returned to, until the battery temperature of the target battery group is greater than or equal to the second temperature threshold, or the temperature rise rate of the battery temperature is greater than or equal to the rate threshold.

[0129] In the process of charging the rechargeable sub-battery group through the energy storage module, as the charging time increases, the voltage of the rechargeable sub-battery group will gradually rise. In order to avoid a large voltage rise in the rechargeable sub-battery group, resulting in a large voltage difference between the sub-battery groups, which creates a safety hazard. In an embodiment of the present application, a charging rise voltage threshold can be set based on the voltages of multiple sub-battery groups. In the case where the voltage of the rechargeable sub-battery group rises once is greater than or equal to the charging rise voltage threshold, the sub-battery groups other than the currently discharged sub-battery group are used as rechargeable sub-battery groups, and the rechargeable sub-battery groups are charged through the energy storage module to realize cyclic charging of multiple sub-battery groups by the energy storage module, that is, the energy storage module alternately charges multiple sub-battery groups, so that the multiple sub-battery groups can alternately increase the voltage, thereby avoiding the situation where the energy storage module charges the sub-battery group, due to a large voltage rise in a certain sub-battery group, resulting in a large voltage difference between the sub-battery groups, which creates a safety hazard.

[0130] In some embodiments, the charging rising voltage threshold may be determined by the following formula 2:

[0131] Where i refers to the i-th charging cycle, i is a positive integer, Refers to the charging rising voltage threshold corresponding to the charging sub-battery pack during the i-th charging, ΔU i Refers to the voltage difference between the sub-battery groups during the i-th charging. For example, in the case where the plurality of sub-battery groups include two sub-battery groups, Refers to the voltage of the first sub-battery group during the i-th charging, such as the voltage of the sub-battery group 11 in FIG. 2 during the i-th charging, Refers to the voltage of the second sub-battery group during the i-th charging, such as the voltage of the sub-battery group 12 in Figure 2 during the i-th charging.

[0132] It should be noted that 1.5 in Formula 2 refers to the corresponding relationship between the charging rising voltage threshold and the voltage difference between the sub-battery groups. This corresponding relationship can be selected based on actual usage requirements, such as 1.3 times, 1.7 times, 2 times, etc.

[0133] In conjunction with Figure 2, assuming that the voltage of sub-battery group 11 is lower than the voltage of sub-battery group 12, when sub-battery group 11 is used as a charging sub-battery group, the control switches SP1 and SP2 are closed, and the control switches SP3, SP4 and SS1 are disconnected. Sub-battery group 11 is used as a charging sub-battery group and charged by the energy storage module. If, until the charging rise voltage of sub-battery group 11 is greater than or equal to the charging rise voltage threshold, the battery temperature of the target battery group is still less than the second temperature threshold, and the temperature rise rate of the battery temperature of the target battery group is still greater than or equal to the rate threshold, then the control switches SP1, SP2 and SS1 are disconnected, and the control switches SP3 and SP4 are closed. Sub-battery group 12, that is, the sub-battery group other than sub-battery group 11, is used as a charging sub-battery group to charge the energy storage module, thereby realizing charging of sub-battery group 11 and sub-battery group 12 based on the energy storage module cycle.

[0134] As can be seen from FIG7 , the cycle conditions for the energy storage module to cycle and charge sub-battery group 11 and sub-battery group 12 are: the battery temperature of the target battery group is less than the second temperature threshold, and the temperature rise rate of the battery temperature of the target battery group during the cycle is continuously greater than or equal to the rate threshold. In the case where the battery temperature of the target battery group is greater than or equal to the second temperature threshold, since the temperature of the target battery group has met the conditions, the self-heating of the target battery group can be directly terminated; in the case where the temperature rise rate of the battery temperature of the target battery group is less than the rate threshold, since charging multiple sub-battery groups through the energy storage module cycle at this time can no longer cause the target battery group to heat up quickly, the energy storage module cycle can be terminated to charge sub-battery group 11 and sub-battery group 12.

[0135] In other words, when the temperature of the target battery pack is greater than or equal to the second temperature threshold, it indicates that the battery temperature of the target battery pack will no longer adversely affect the external charging power of the target battery pack, and thus the self-heating of the target battery pack can be terminated.

[0136] Also, as the energy storage module circulates and continuously charges the sub-battery group, the voltage of the energy storage module will gradually rise, and the voltage of the sub-battery group will gradually rise, causing the voltage difference between the voltage of the sub-battery group and the voltage of the energy storage module to gradually decrease. At this time, due to the decrease in the voltage difference, the current in the charging circuit is weakened, which in turn causes the heat generation of the charging circuit to decrease, and the temperature rise rate of the battery temperature of the target battery group is reduced. When the temperature rise rate of the battery temperature of the target battery group is less than the rate threshold, it indicates that the voltage between the current sub-battery group and the energy storage module is already relatively close. If the self-heating of the target battery group continues to be achieved in this way, the temperature rise rate of the battery temperature of the target battery group will only become smaller and smaller. At this time, in order to improve the self-heating efficiency of the target battery group, it is necessary to adjust the charging and discharging method between the target battery group and the energy storage module.

[0137] In some embodiments, as shown in FIG7 , when it is detected that the battery temperature of the target battery pack is less than a second temperature threshold and the temperature rise rate of the battery temperature of the target battery pack is less than a rate threshold, the charge and discharge switch group can be controlled to charge the energy storage module through the multiple sub-battery packs in a cycle. The details of charging the energy storage module through the multiple sub-battery packs in a cycle can be referred to the relevant description of step (2) above and will not be repeated here.

[0138] Step 304: During the charging and discharging process between the target battery pack and the energy storage module, the battery temperature of the target battery pack is monitored by the detection module.

[0139] Step 305: When it is monitored that the battery temperature of the target battery pack is greater than or equal to a second temperature threshold, the charge and discharge switch group is controlled to disconnect the charge and discharge circuit between the target battery pack and the energy storage module, and the second temperature threshold is greater than the first temperature threshold.

[0140] In some embodiments, when it is monitored that the battery temperature of the target battery pack is greater than or equal to the second temperature threshold, each switch in the charge and discharge switch group can be controlled to be disconnected, thereby disconnecting the charge and discharge circuit between the target battery pack and the energy storage module.

[0141] Next, the overall solution of the embodiment of the present application is introduced with reference to Figure 8. As shown in Figure 8, Umax refers to the maximum voltage among the voltages of the multiple sub-battery groups, that is, the voltage of the first sub-battery group, Uc refers to the voltage of the energy storage module, and d refers to the first voltage threshold. When the battery temperature of the target battery group is less than or equal to the first temperature threshold, it is first determined whether the voltage difference between the multiple sub-battery groups in the target battery group is greater than the second voltage threshold. When the voltage difference between the multiple sub-battery groups is greater than the second voltage threshold, the voltage difference between the multiple sub-battery groups can be reduced in the manner shown in Figure 4 above.

[0142] If the voltage difference between the multiple sub-battery groups is less than or equal to the second voltage threshold, it indicates that the voltage difference between the multiple sub-battery groups of the target battery group is small. In this case, the first sub-battery group with the highest voltage among the multiple sub-battery groups can be determined, and based on the magnitude relationship between the voltage of the first sub-battery group and the voltage of the energy storage module, different charging and discharging modes can be implemented by opening or closing multiple switches.

[0143] When the voltage of the first sub-battery group is greater than the voltage of the energy storage module, and the difference between the voltage of the first sub-battery group and the voltage of the energy storage module is greater than the first voltage threshold, or when the energy storage module is used to charge multiple sub-battery groups in a cycle and the temperature rise rate of the battery temperature of the target battery group is less than the rate threshold, the energy storage module can be charged in a cycle through the multiple sub-battery groups in the manner shown in FIG5 above. When the absolute value of the difference between the voltage of the first sub-battery group and the voltage of the energy storage module is less than or equal to the first voltage threshold, or when the energy storage module is used to charge the energy storage module in a cycle through the multiple sub-battery groups and the temperature rise rate of the battery temperature of the target battery group is less than the rate threshold, the energy storage module can be charged in series through the multiple sub-battery groups in the manner shown in FIG6 above. When the voltage of the first sub-battery group is less than the voltage of the energy storage module, and the difference between the voltage of the energy storage module and the voltage of the first sub-battery group is greater than the first voltage threshold, or when the temperature rise rate of the battery temperature of the target battery group is less than the rate threshold during the process of charging the energy storage module through the multiple sub-battery groups in series, the multiple sub-battery groups can be charged in a cycle through the energy storage module in the manner shown in FIG7 above.

[0144] Through the above-mentioned self-heating method, it is possible to ensure that before the battery temperature of the target battery pack is greater than or equal to the second temperature threshold, the temperature rise rate of the battery temperature remains at a high rate, that is, the battery temperature rises at a high rate, thereby achieving a rapid rise in the battery temperature and ensuring the self-heating efficiency of the target battery pack. In addition, when the sub-battery packs and the energy storage module are cyclically charged and discharged, the sub-battery packs work alternately, such as alternately charging the energy storage module through multiple sub-battery packs, and alternately charging multiple sub-battery packs through the energy storage module, so as to ensure that when the self-heating of the target battery pack is achieved, the voltage between the sub-battery packs alternately rises or falls, so that the voltage difference between the sub-battery packs is always kept within the allowable range, so as to ensure the safety and stability of the target battery pack during the self-heating process.

[0145] Figure 9 is a structural schematic diagram of a vehicle provided in an embodiment of the present application. The vehicle 900 includes a memory 901 and a controller 902. The memory 901 is used to store computer programs, and the controller 902 is used to execute the computer programs stored in the memory 901 to implement the steps of the above-mentioned battery pack self-heating method.

[0146] The memory 901 may include one or more computer-readable storage media, which may be non-transitory. The memory 901 may also include high-speed random access memory and non-volatile memory, such as one or more disk storage devices and flash memory storage devices. In some embodiments, the non-transitory computer-readable storage medium in the memory 901 is used to store at least one instruction, and the at least one instruction is used to be executed by the controller 902 to implement the battery pack self-heating method provided in the method embodiment of the present application.

[0147] The controller 902 may include one or more processing cores, such as a 4-core processor, an 8-core processor, etc. The controller 902 may be implemented in at least one hardware form of DSP (Digital Signal Processing), FPGA (Field Programmable Gate Array), or PLA (Programmable Logic Array). The controller 902 may also include a main processor and a coprocessor. The main processor is a processor for processing data in the awake state, also known as a CPU (Central Processing Unit); the coprocessor is a low-power processor for processing data in the standby state. In some embodiments, the controller 902 may be integrated with a GPU (Graphics Processing Unit), which is responsible for rendering and drawing the content to be displayed on the display screen. In some embodiments, the controller 902 may also include an AI (Artificial Intelligence) processor, which is used to process computing operations related to machine learning.

[0148] Those skilled in the art will appreciate that the structure shown in FIG9 does not limit the terminal 900 and may include more or fewer components than shown, or combine certain components, or adopt a different component arrangement.

[0149] In some embodiments, a computer-readable storage medium is further provided, the storage medium storing a computer program. When executed by a controller, the computer program implements the steps of the battery pack self-heating method described in the above embodiments. For example, the computer-readable storage medium may be a ROM, RAM, CD-ROM, magnetic tape, floppy disk, or optical data storage device.

[0150] It is worth noting that the computer-readable storage medium mentioned in the embodiments of the present application may be a non-volatile storage medium, in other words, a non-transitory storage medium.

[0151] It should be understood that all or part of the steps for implementing the above embodiments may be implemented using software, hardware, firmware, or any combination thereof. When implemented using software, all or part of the steps may be implemented in the form of a computer program product. The computer program product may include one or more computer instructions. The computer instructions may be stored in the computer-readable storage medium.

[0152] That is, in some embodiments, a computer program product containing instructions is also provided, which, when executed on a computer, enables the computer to execute the steps of the battery pack self-heating method described above.

[0153] It should be understood that the "at least one" mentioned herein refers to one or more, and "a plurality of" refers to two or more. In the description of the embodiments of the present application, unless otherwise specified, " / " means or, for example, A / B can mean A or B; "and / or" in this article is merely a description of the association relationship of associated objects, indicating that three relationships can exist, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in order to facilitate a clear description of the technical solutions of the embodiments of the present application, in the embodiments of the present application, words such as "first" and "second" are used to distinguish between identical or similar items with substantially the same functions and effects. Those skilled in the art will understand that words such as "first" and "second" do not limit the quantity and execution order, and words such as "first" and "second" do not necessarily limit them to be different.

[0154] It should be noted that the information (including but not limited to user device information, user personal information, etc.), data (including but not limited to data used for analysis, stored data, displayed data, etc.) and signals involved in the embodiments of this application are all authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data need to comply with the relevant laws, regulations and standards of relevant countries and regions.

[0155] The above description is an embodiment provided for this application and is not intended to limit this application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of this application should be included in the scope of protection of this application.

Claims

1. A battery pack self-heating system, characterized in that: The system comprises: A target battery pack, the target battery pack comprising a plurality of sub-battery packs for providing electrical energy; An energy storage module, used to store the electric energy released by the target battery pack and charge the target battery pack with the stored electric energy; A charge and discharge switch group, which is connected between the target battery group and the energy storage module and is used to control the on and off of the charge and discharge circuit between the target battery group and the energy storage module; a detection module, the detection module being connected to the target battery group and the energy storage module respectively, and being used to detect the voltage of each sub-battery group in the multiple sub-battery groups, the voltage of the energy storage module, and the battery temperature of the target battery group; A control module, the control module is respectively connected to the detection module and the charge and discharge switch group, and is used to control the charge and discharge switch group based on the voltages of the multiple sub-battery groups, the voltage of the energy storage module and the battery temperature of the target battery group to achieve charging and discharging between the target battery group and the energy storage module.

2. The system according to claim 1, characterized in that The charge and discharge switch group includes a plurality of switches, wherein the positive electrode of each sub-battery group is respectively connected to one of the switches, and the other end of the switch is connected to one end of the energy storage module; the negative electrode of each sub-battery group is respectively connected to one of the switches, and the other end of the switch is connected to the other end of the energy storage module; one of the switches is connected between two adjacent sub-battery groups among the plurality of sub-battery groups; The control module is used to control the opening or closing of the multiple switches to control the on-off of the charge and discharge circuit between a single sub-battery group among the multiple sub-battery groups and the energy storage module, or to control the on-off of the charge and discharge circuit between the series path of the multiple sub-battery groups and the energy storage module.

3. A battery pack self-heating method applied to the system as claimed in claim 1 or 2, characterized in that: The method comprises: Acquiring the battery temperature of the target battery pack by the detection module; When the battery temperature of the target battery group is less than a first temperature threshold, acquiring the voltages of the plurality of sub-battery groups included in the target battery group and the voltage of the energy storage module through the detection module; Based on the voltages of the multiple sub-battery groups and the voltage of the energy storage module, controlling the charge and discharge switch group to achieve conduction of the charge and discharge circuit between the target battery group and the energy storage module; During the charging and discharging process between the target battery pack and the energy storage module, monitoring the battery temperature of the target battery pack by the detection module; When it is monitored that the battery temperature of the target battery group is greater than or equal to a second temperature threshold, the charge and discharge switch group is controlled to disconnect the charge and discharge circuit between the target battery group and the energy storage module, and the second temperature threshold is greater than the first temperature threshold.

4. The method according to claim 3, characterized in that The controlling the charge and discharge switch group based on the voltages of the plurality of sub-battery groups and the voltage of the energy storage module to achieve conduction of the charge and discharge circuit between the target battery group and the energy storage module comprises: Determine a first sub-battery group having the largest voltage from among the plurality of sub-battery groups; When the voltage of the first sub-battery group is greater than the voltage of the energy storage module, and the difference between the voltage of the first sub-battery group and the voltage of the energy storage module is greater than a first voltage threshold, control the charge and discharge switch group to charge the energy storage module through the plurality of sub-battery groups in a cycle; When the absolute value of the difference between the voltage of the first sub-battery group and the voltage of the energy storage module is less than or equal to the first voltage threshold, controlling the charge and discharge switch group to charge the energy storage module through the multiple sub-battery groups connected in series; When the voltage of the first sub-battery group is lower than the voltage of the energy storage module, and the difference between the voltage of the energy storage module and the voltage of the first sub-battery group is greater than the first voltage threshold, the charge and discharge switch group is controlled to charge the multiple sub-battery groups through the energy storage module cycle.

5. The method according to claim 4, characterized in that The multiple sub-battery groups include two sub-battery groups; and the controlling the charge and discharge switch group to charge the energy storage module cyclically through the multiple sub-battery groups includes: Taking the first sub-battery group as a discharge sub-battery group, and determining a discharge loss voltage threshold corresponding to the discharge sub-battery group based on the voltages of the plurality of sub-battery groups; Control the switches in the charge-discharge switch group connected to the positive and negative electrodes of the discharge sub-battery group to be closed, and other switches to be opened, so as to charge the energy storage module through the discharge sub-battery group; During the process of the discharge sub-battery pack charging the energy storage module, the detection module monitors measuring the battery temperature of the target battery group, the temperature rise rate of the battery temperature of the target battery group, and the discharge loss voltage of the discharge sub-battery group; When it is monitored that the battery temperature of the target battery group is lower than the second temperature threshold, the temperature rise rate of the battery temperature of the target battery group is greater than or equal to the rate threshold, and the discharge loss voltage of the discharge sub-battery group is greater than or equal to the discharge loss voltage threshold, another sub-battery group is used as the discharge sub-battery group, and the step of determining the discharge loss voltage threshold corresponding to the discharge sub-battery group based on the voltages of the multiple sub-battery groups is returned until the battery temperature of the target battery group is greater than or equal to the second temperature threshold, or the temperature rise rate of the battery temperature is lower than the rate threshold.

6. The method according to claim 5, characterized in that In the process of the discharge sub-battery pack charging the energy storage module, after monitoring the battery temperature of the target battery pack, the temperature rise rate of the battery temperature of the target battery pack, and the discharge loss voltage of the discharge sub-battery pack by the detection module, the method further includes: When it is monitored that the battery temperature of the target battery group is lower than the second temperature threshold and the temperature rise rate of the battery temperature of the target battery group is lower than the rate threshold, the charge and discharge switch group is controlled to charge the energy storage module through the multiple sub-battery groups connected in series.

7. The method according to claim 4 or 6, characterized in that The controlling the charge and discharge switch group to charge the energy storage module through the plurality of sub-battery groups connected in series comprises: Control switches on the series paths of the multiple sub-battery groups to be closed and other switches to be opened, so as to charge the energy storage module through the multiple sub-battery groups connected in series; In the process of the multiple sub-battery groups being connected in series to charge the energy storage module, the battery temperature of the target battery group and the temperature rise rate of the battery temperature of the target battery group are monitored by the detection module; When it is monitored that the battery temperature of the target battery group is lower than the second temperature threshold, and the temperature rise rate of the battery temperature of the target battery group is greater than or equal to the rate threshold, the energy storage module continues to be charged by connecting the multiple sub-battery groups in series until the battery temperature of the target battery group is greater than or equal to the second temperature threshold, or the temperature rise rate of the battery temperature is lower than the rate threshold.

8. The method according to claim 7, characterized in that In the process of connecting the multiple sub-battery groups in series to charge the energy storage module, after monitoring the battery temperature of the target battery group and the temperature rise rate of the battery temperature of the target battery group by the detection module, the method further includes: When it is monitored that the battery temperature of the target battery group is lower than the second temperature threshold and the temperature rise rate of the battery temperature of the target battery group is lower than the rate threshold, the charge and discharge switch group is controlled to charge the multiple sub-battery groups through the energy storage module cycle.

9. The method according to claim 4 or 8, characterized in that The multiple sub-battery groups include two sub-battery groups; the controlling the charge and discharge switch group to charge the multiple sub-battery groups cyclically through the energy storage module includes: Determine a second sub-battery group having the smallest voltage from among the plurality of sub-battery groups; Using the second sub-battery group as a charging sub-battery group, and determining a charging rising voltage threshold corresponding to the charging sub-battery group based on the voltage of the energy storage module and the voltage of the charging sub-battery group; Control the switches in the charge-discharge switch group connected to the positive and negative electrodes of the charging sub-battery group to be closed, and other switches to be opened, so as to charge the charging sub-battery group through the energy storage module; In the process of the energy storage module charging the charging sub-battery group, the detection module monitors the battery temperature of the target battery group, the temperature rise rate of the battery temperature of the target battery group, and the charging rise voltage of the charging sub-battery group; When it is monitored that the battery temperature of the target battery group is lower than the second temperature threshold, the temperature rise rate of the battery temperature of the target battery group is greater than or equal to the rate threshold, and the charging rise voltage of the charging sub-battery group is greater than or equal to the charging rise voltage threshold, another sub-battery group is used as the charging sub-battery group, and the step of determining the charging rise voltage threshold corresponding to the charging sub-battery group based on the voltage of the energy storage module and the voltage of the charging sub-battery group is returned until the battery temperature of the target battery group is greater than or equal to the second temperature threshold, or the temperature rise rate of the battery temperature is lower than the rate threshold.

10. The method according to claim 9, characterized in that In the process of the energy storage module charging the charging sub-battery group, after the detection module monitors the battery temperature of the target battery group, the temperature rise rate of the battery temperature of the target battery group, and the charging rise voltage of the charging sub-battery group, the method further includes: When it is monitored that the battery temperature of the target battery pack is lower than the second temperature threshold and the temperature rise rate of the battery temperature of the target battery pack is lower than the rate threshold, the charge and discharge switch is controlled. The energy storage module is charged by cycling through the multiple sub-battery groups.

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