Powertrain systems and battery balancing methods, electric vehicles, storage media

Abstract

This application provides a power system and battery balancing method, an electric vehicle, and a storage medium; wherein, the power system includes: a controller, a motor controller, a motor, and a battery module, the battery module including at least a first battery pack and a second battery pack connected in series with the first battery pack; the controller is connected to the motor controller, and the motor is connected between the motor controller and the battery module; the controller is configured to: determine a first balancing current and a first balancing time of the first battery pack based on the current state parameters of the battery module; control the motor controller to open the circuit between the positive and negative terminals of the first battery pack to charge the energy of the first battery pack to the motor according to the first balancing current, based on the first balancing current and the first balancing time; and control the motor controller to open the circuit between the positive and negative terminals of the second battery pack to discharge the energy stored in the motor to the second battery pack according to the first balancing current.

Description

Technical Field

[0001] This application relates to vehicle technology, including but not limited to power systems and battery balancing methods, electric vehicles, and storage media. Background Technology

[0002] Battery balancing is a key technology in battery management, used to address the inconsistency in State of Charge (SOC) caused by factors such as manufacturing differences and varying aging rates when multiple battery packs or cells are connected in series. Through balancing control, the overall capacity utilization and safety of the battery can be improved, extending its lifespan. Summary of the Invention

[0003] In a first aspect, embodiments of this application provide a power system, the power system comprising: a controller, a motor controller, a motor, and a battery module, wherein the battery module includes at least a first battery pack and a second battery pack connected in series with the first battery pack; wherein the controller is connected to the motor controller, and the motor is connected between the motor controller and the battery module; the controller is configured to:

[0004] The current cell charging capability of the battery module is determined based on the current state parameters of multiple cells in the battery module; wherein the current state parameters of the cells include at least one of the following: SOC, temperature, and voltage;

[0005] A first equalization current is determined based on the minimum charging current allowed by the charging device and the current charging capacity of the battery cell.

[0006] Obtain the current status parameters of the first battery pack;

[0007] Based on the pre-defined mapping relationship, determine the first mapping value corresponding to the current state parameter of the first battery pack;

[0008] Obtain the current state parameters of the first battery cell; wherein, the first battery cell is the battery cell with the lowest cell voltage in the first battery pack and the second battery pack;

[0009] Based on the pre-calibrated mapping relationship, determine the second mapping value corresponding to the current state parameters of the first cell;

[0010] The current inter-pack imbalance of the first battery pack is determined based on the difference between the first mapping value and the second mapping value.

[0011] The first equalization time is determined based on the current imbalance of the private room and the first equalization current.

[0012] Performing inter-packet balancing, the inter-packet balancing includes: controlling the motor controller to open the circuit between the positive and negative terminals of the first battery pack according to the first balancing current and the first balancing time, so as to charge the motor with the energy of the first battery pack according to the first balancing current; and,

[0013] The motor controller is controlled to open the circuit between the positive and negative terminals of the second battery pack, so as to discharge the energy stored in the motor to the second battery pack according to the first equalization current.

[0014] It is understood that, in the above embodiments, for a power system with a motor and a motor controller, the first equalization current used for cell equalization is determined based on the minimum charging current allowed by the charging equipment and the current cell charging capacity. This not only helps to effectively prevent battery overcurrent during equalization, but also ensures that the charging equipment can charge the battery modules smoothly, thereby improving the equalization safety and efficiency of the power system.

[0015] Furthermore, in some embodiments, determining the current cell charging capability of the battery module based on the current state parameters of the plurality of cells in the battery module includes: determining the maximum charging current that the charging device is currently allowed to provide to the i-th cell based on the current state parameters of the i-th cell in the battery module; and determining the current cell charging capability of the battery module based on the minimum value among the maximum charging currents of the plurality of cells.

[0016] It is understood that in the above embodiments, the current cell charging capability of the battery module is determined based on the maximum charging current of multiple cells in the battery module, and the maximum charging current of a cell is adapted to the current actual state of the cell; thus, it is beneficial to determine a more reasonable balancing current, thereby helping to shorten the balancing time.

[0017] For example, in some embodiments, determining the current cell charging capability of the battery module based on the minimum of the maximum charging currents of the plurality of cells includes: the current cell charging capability of the battery module is equal to the minimum of the maximum charging currents of each cell in the battery module.

[0018] It is understood that each cell has its own maximum allowable charging current at the current moment, and the current cell charging capacity of the battery module is equal to the minimum value among the maximum charging currents of each cell in the battery module. This can prevent other cells from exceeding their charging current capacity, i.e., charging current exceeding the window, thereby determining a more reasonable equalization current while ensuring safety during the equalization period.

[0019] Furthermore, in some embodiments, determining the first equalization time based on the current room imbalance and the first equalization current includes: determining the first equalization time based on the ratio of the current room imbalance to the first equalization current; wherein the first equalization time is positively correlated with the ratio.

[0020] It is understood that in the above embodiments, the first equalization time is determined based on the ratio of the current room imbalance to the first equalization current; that is, the first equalization time is adapted to the current room imbalance and the current equalization current, which is beneficial for the system to reasonably evaluate the time required for the equalization process, thereby improving the room equalization performance.

[0021] Further, in some embodiments, determining the first equalization current based on the minimum charging current allowed by the charging device and the current cell charging capability includes: determining a charging request current based on the minimum charging current allowed by the charging device; wherein the charging request current refers to a charging current requested by the charging device, and the charging request current is greater than or equal to the minimum charging current; and determining the first equalization current based on the current cell charging capability and the charging request current.

[0022] It is understood that in the above embodiments, the charging request current is the charging current expected to be obtained from the charging device. If the charging request current is less than the minimum charging current allowed by the charging device (e.g., the minimum charging current specified by the charging protocol), the charging device will interrupt charging.

[0023] Furthermore, in some embodiments, determining the first equalization current based on the current cell charging capability and the charging request current includes: determining the product of the charging request current and a preset first coefficient; determining the first equalization current based on the difference between the current cell charging capability and the product; wherein the first equalization current is positively correlated with the difference.

[0024] It is understood that in the above embodiments, the smaller the charging request current, the larger the determined first equalization current. In the embodiment where the determination of the first equalization time is based on the ratio of the current inter-packet imbalance to the first equalization current, the larger the first equalization current, the shorter the determined first equalization time. Thus, it is beneficial to complete the inter-packet equalization in a shorter time without affecting the normal operation of the charging task of the charging device (i.e., equalization will not cause the charging device to interrupt charging).

[0025] Furthermore, in some embodiments, the execution of inter-packet equalization includes: during the charging process of the charging device to the battery module, if the equalization execution conditions are met, performing the inter-packet equalization.

[0026] Furthermore, in some embodiments, the step of performing inter-packet equalization if the equalization execution condition is met during the charging process of the charging device to the battery module includes: performing inter-packet equalization if the equalization execution condition is met during the charging process of the charging device to the battery module and the motor controller is in an idle state.

[0027] It is understood that in the above embodiments, inter-packet equalization is performed while the charging device is charging the battery module and the motor controller is idle (i.e., without other tasks). This ensures the safety of inter-packet equalization and does not affect the motor controller's execution of other tasks due to the motor controller performing inter-packet equalization.

[0028] Furthermore, in some embodiments, the equalization execution condition includes at least: the current cell charging capacity is greater than or equal to a first current threshold; wherein the first current threshold is greater than or equal to the sum of the minimum charging current and the minimum equalization current allowed for inter-cell equalization.

[0029] It is understood that the maximum charging current represents the cell's charging capability under the current operating conditions. If this charging capability is too low, meaning the maximum charging current is too small due to inter-cell balancing, it may cause the charging device to interrupt charging, or the inter-cell balancing may fail to perform to ensure uninterrupted charging. Based on this consideration, in the above embodiments, the prerequisite for performing inter-cell balancing during charging includes at least: the maximum charging current is greater than or equal to a first current threshold; thus, both normal charging during charging and the execution of inter-cell balancing can be ensured.

[0030] Furthermore, in some embodiments, the equalization execution conditions further include: the maximum cell temperature of the battery module is less than or equal to a first temperature threshold; the SOC of the first battery pack is greater than or equal to the first SOC threshold and less than or equal to a second SOC threshold; and the minimum cell voltage of the battery module is greater than or equal to the first voltage threshold and less than or equal to the second voltage threshold.

[0031] It is understood that in the above embodiments, the battery temperature, SOC, and battery voltage should not be too high or too low when performing cell equalization; thus, cell equalization is ensured to be performed within a safe range.

[0032] Further, in some embodiments, the controller is also configured to: acquire the current state parameters of the second battery cell; determine a third mapping value corresponding to the current state parameters of the second battery cell according to a pre-calibrated mapping relationship; acquire the current state parameters of the third battery cell; wherein the third battery cell is the battery cell with the lowest cell voltage in the first battery pack; determine a fourth mapping value corresponding to the current state parameters of the third battery cell according to the pre-calibrated mapping relationship; determine the current unbalance degree within the pack of the second battery cell according to the difference between the third mapping value and the fourth mapping value; wherein the second battery cell is any cell in the first battery pack and the second battery pack; determine a second balancing current of the second battery cell according to the average voltage of the battery cell and the resistance value of the balancing resistor connected to the second battery cell; determine a second balancing time according to the current unbalance degree within the pack and the second balancing current; and balance the second battery cell according to the second balancing current and the second balancing time.

[0033] It is understandable that when a traditional power system performs other functions, such as charging and discharging a single battery pack, the voltage distribution within the battery changes, rendering previous equalization calculations unreliable. Continuing to perform these functions would lead to incorrect equalization. Therefore, the above embodiment introduces a multi-level collaborative equalization method, including independent inter-packet equalization and intra-packet equalization methods. These two methods calculate independently, ensuring that individual charging and discharging of multiple battery packs does not interfere with the voltage distribution within the battery packs, thus guaranteeing the accuracy and reliability of the equalization results.

[0034] Secondly, embodiments of this application provide a battery balancing method, the method comprising: determining the current cell charging capability of a battery module based on current state parameters of multiple cells in a battery module; wherein the battery module includes at least a first battery pack and a second battery pack connected in series with the first battery pack; the current state parameters of the cells include at least one of the following: SOC, temperature, and voltage; determining a first balancing current based on the minimum charging current allowed by the charging device and the current cell charging capability; obtaining the current state parameters of the first battery pack; determining a first mapping value corresponding to the current state parameters of the first battery pack according to a pre-calibrated mapping relationship; obtaining the current state parameters of a first cell; wherein the first cell is the cell with the lowest cell voltage in the first battery pack and the second battery pack; and so on. According to the pre-calibrated mapping relationship, a second mapping value corresponding to the current state parameter of the first cell is determined; the difference between the first mapping value and the second mapping value is used to determine the current inter-packet imbalance of the first battery pack; a first balancing time is determined based on the current inter-packet imbalance and the first balancing current; inter-packet balancing is performed, wherein performing inter-packet balancing includes: according to the first balancing current and the first balancing time, controlling the motor controller to open the circuit between the positive and negative terminals of the first battery pack to charge the energy of the first battery pack to the motor according to the first balancing current; and controlling the motor controller to open the circuit between the positive and negative terminals of the second battery pack connected in series with the first battery pack to discharge the energy stored in the motor to the second battery pack according to the first balancing current.

[0035] Thirdly, embodiments of this application provide an electric vehicle, which includes a vehicle body and the power system described in one or more of the above embodiments.

[0036] Fourthly, embodiments of this application provide a computer-readable storage medium having a computer program stored thereon that, when executed by a controller or an electric vehicle, implements the method described in the second aspect.

[0037] Fifthly, embodiments of this application provide a computer program product, including a computer program or instructions, which, when executed by a controller or an electric vehicle, implement the method described in the second aspect of this application.

[0038] In a sixth aspect, embodiments of this application provide a computer program that causes a controller or electric vehicle to perform the method described in the second aspect.

[0039] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0040] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the specification, serve to explain the technical solutions of this application. Obviously, the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0041] The flowcharts shown in the accompanying drawings are merely illustrative and do not necessarily include all content and operations / steps, nor do they necessarily have to be performed in the described order. For example, some operations / steps can be broken down, while others can be combined or partially combined; therefore, the actual execution order may change depending on the specific circumstances.

[0042] Figure 1 A schematic diagram of the power system provided in the embodiments of this application. Figure 1 ;

[0043] Figure 2 A schematic diagram of the power system provided in the embodiments of this application. Figure 2 ;

[0044] Figure 3 A schematic diagram illustrating the implementation process of the battery balancing method provided in the embodiments of this application;

[0045] Figure 4 A schematic diagram illustrating a further implementation of step 302 provided in an embodiment of this application;

[0046] Figure 5 A schematic diagram illustrating a further implementation of step 402 provided in an embodiment of this application;

[0047] Figure 6 A schematic diagram of a multi-level collaborative balancing method based on an electric drive system is provided for embodiments of this application.

[0048] Figure 7 This is a schematic diagram of the structure of an electric vehicle provided in an embodiment of this application. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the specific technical solutions of this application will be further described in detail below with reference to the accompanying drawings of the embodiments of this application. The following embodiments are used to illustrate this application, but are not intended to limit the scope of this application.

[0050] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit this application.

[0051] In the following description, references to "some embodiments," "this embodiment," "this application embodiment," and examples, etc., describe a subset of all possible embodiments. However, it is understood that "some embodiments" may be the same subset or different subset of all possible embodiments and may be combined with each other without conflict.

[0052] The descriptions such as "first," "second," and "third" appearing in the embodiments of this application do not have a specific meaning (such as no order, nor do they indicate a special limitation on the number of devices in the embodiments of this application), but are merely for the purpose of clearly describing the embodiments of this application and do not constitute any limitation on the embodiments of this application.

[0053] This application provides a power system.

[0054] Figure 1 A schematic diagram of the power system provided in the embodiments of this application. Figure 1 ;like Figure 1 As shown, the power system 100 includes a battery module 101, a motor controller 102, a motor 103, and a controller 104; wherein the battery module 101 includes at least a first battery pack 1011 and a second battery pack 1012 connected in series with the first battery pack 1011; wherein the controller 104 is connected to the motor controller 102, and the motor 103 is connected between the motor controller 102 and the battery module 101. Figure 1 As shown, the motor controller 102 is connected to the first end of the motor 103 and the positive and negative terminals of the battery module 101. The second end of the motor 103 is connected to the negative terminal of the first battery pack 1011 and the positive terminal of the second battery pack 1012, respectively.

[0055] It is understood that, in this embodiment, one of the functions of the motor controller 102 is to establish a current path between battery packs, enabling the transfer of energy from one battery pack to another. As an energy regulator, the motor controller 102 can precisely control the magnitude and direction of the current, thereby achieving efficient inter-pack balance.

[0056] For example, the structure of the motor controller 102 is as follows: Figure 2As shown, the motor controller 102 includes a first bridge arm and a second bridge arm. The first bridge arm includes switching transistors T1, T2, and T3, and the second bridge arm includes switching transistors T4, T5, and T6. The controller 104 establishes a current path between the battery packs by controlling the closing or opening of the switching transistors, thereby realizing energy transfer. For example, the controller 104 controls the switching transistors of the first bridge arm to close to form a closed loop between the positive and negative terminals of the first battery pack 1011, thereby allowing energy from the first battery pack 1011 to flow into the motor 103; and the controller 104 controls the switching transistors of the second bridge arm to close to form a closed loop between the positive and negative terminals of the second battery pack 1012, thereby allowing energy from the motor 103 to flow into the second battery pack 1012. Thus, energy transfer from the first battery pack 1011 to the second battery pack 1012 is realized.

[0057] It should be noted that, in this embodiment, the structure of the motor controller 102 is not limited to... Figure 2 As shown, the structure of the motor controller 102 can be varied. In short, the current path between the two battery packs can be established by controlling the working state of the motor controller 102 through the controller 104.

[0058] It is understood that in this embodiment, the motor 103 is used to connect the controller 104 and the motor controller 102, and is responsible for transmitting electrical energy between the battery pack and the motor controller. The motor 103 can be a motor winding. In some embodiments, the motor 103 may include a permanent magnet synchronous motor, an asynchronous motor, and other types of motors. The motor 103 can be three-phase, five-phase, six-phase, nine-phase, etc., and may include multiple sets of windings. The following example illustrates the structure of the motor 103 as a three-phase motor. Figure 2 As shown, the motor 103 includes three-phase coils (i.e., inductors L1, L2, and L3). Of course, in this embodiment, the structure of the motor 103 is not limited to... Figure 2 As shown, the structure of the motor 103 can be varied. In general, the motor 103 has at least one phase inductor with energy storage and discharge capabilities.

[0059] For the power system described in one or more of the above embodiments, such as Figure 3 As shown, controller 104 is used to perform the following steps 301 to 303:

[0060] Step 301: Determine the first equalization current and the first equalization time of the first battery pack based on the current state parameters of the battery module.

[0061] Step 302: Based on the first equalization current and the first equalization time, control the motor controller to open the circuit between the positive and negative terminals of the first battery pack, so as to charge the energy of the first battery pack to the motor according to the first equalization current;

[0062] Step 303: Control the motor controller to open the circuit between the positive and negative terminals of the second battery pack, so as to discharge the energy stored in the motor to the second battery pack according to the first equalization current.

[0063] It is understood that steps 302 and 303 are inter-battery balancing steps performed by controller 104. In this embodiment, for a power system with a motor controller, the balancing current and balancing time that conform to the current actual operating conditions are calculated based on the current state parameters of the battery module, and then the motor controller is controlled to perform inter-battery balancing based on the balancing current and balancing time; thus, it is beneficial to improve the efficiency and accuracy of battery balancing, thereby ensuring the overall performance of the battery module and the service life of the battery.

[0064] The following sections will describe further optional implementation methods for each of the above steps, as well as related terms.

[0065] Step 301: Determine the first equalization current and the first equalization time of the first battery pack based on the current state parameters of the battery module.

[0066] As can be understood, balancing current refers to the current value used to adjust the charge level through balancing resistors or energy transfer methods during the process of achieving balancing within or between battery packs. Balancing time refers to the time required to eliminate the imbalance state of a particular cell or battery pack under a given balancing current.

[0067] In some embodiments, such as Figure 4 As shown, step 301 may further include steps 401 to 404:

[0068] Step 401: Determine the current cell charging capability of the battery module based on the current state parameters of the multiple cells in the battery module.

[0069] It can be understood that the current cell charging capability of the battery module is the maximum charging current that the charging device can safely output under the current battery state (such as temperature, voltage, SOC, etc.).

[0070] Further, in some embodiments, step 401 may include: determining the maximum charging current that the charging device is currently allowed to provide to the i-th cell based on the current state parameters of the i-th cell in the battery module; determining the current cell charging capability of the battery module based on the minimum value among the maximum charging currents of the plurality of cells; wherein i is greater than or equal to 1.

[0071] In this embodiment, the current state parameters of the battery cell are not limited; they are simply parameters characterizing the current state of the battery cell. For example, the current state parameters of the battery cell include, but are not limited to, at least one of the following: SOC, temperature, and voltage.

[0072] In one possible implementation, the maximum charging current corresponding to the current state parameter can be obtained by querying the mapping table based on the current state parameter of the i-th cell.

[0073] In one possible implementation, determining the current cell charging capability of the battery module based on the minimum of the maximum charging currents of the plurality of cells includes: the current cell charging capability of the battery module is equal to the minimum of the maximum charging currents of each cell in the battery module.

[0074] It is understood that each cell has its own maximum allowable charging current at the current moment, and the current cell charging capacity of the battery module is equal to the minimum value among the maximum charging currents of each cell in the battery module. This can prevent other cells from exceeding their charging current capacity, i.e., charging current exceeding the window, thereby determining a more reasonable equalization current while ensuring safety during the equalization period.

[0075] Step 402: Determine the first equalization current based on the minimum charging current allowed by the charging device and the current charging capacity of the battery cell.

[0076] In some embodiments, the minimum charging current allowed by the charging device may be the minimum charging current specified by the charging protocol. If the charging current value requested from the charging device is lower than this minimum charging current, it may cause the charging device to stop charging the battery module. For example, this could cause the charging station to trip.

[0077] Furthermore, in some embodiments, such as Figure 5 As shown, step 402 may include the following steps 501 and 502:

[0078] Step 501: Determine the charging request current based on the minimum charging current allowed by the charging device; wherein the charging request current refers to the charging current requested by the charging device, and the charging request current is greater than or equal to the minimum charging current.

[0079] Step 502: Determine the first equalization current based on the current cell charging capacity and the charging request current.

[0080] As can be understood, a charging request current is the desired charging current obtained from the charging device. If this charging request current is less than the minimum charging current allowed by the charging device (e.g., the minimum charging current specified by the charging protocol), it will cause the charging device to interrupt charging.

[0081] In the above embodiments, the charging request current is determined based on the minimum charging current allowed by the charging device and the charging request current is greater than or equal to the minimum charging current. Furthermore, a first equalization current is determined based on the current cell charging capacity (i.e., the current battery charging capacity) and the charging request current. In this way, the determined first equalization current can meet the battery equalization requirements without affecting the normal operation of the charging device's charging task (i.e., it will not cause the charging device to interrupt charging).

[0082] In some embodiments, step 502 may further include: determining the product of the charging request current and a preset first coefficient; determining the first equalization current based on the difference between the current cell charging capacity and the product; wherein the first equalization current is positively correlated with the difference. That is, the smaller the charging request current, the larger the determined first equalization current. In the embodiment where the determination of the first equalization time is based on the ratio of the current inter-cell imbalance to the first equalization current, the larger the first equalization current, the shorter the determined first equalization time. Thus, it is beneficial to complete the inter-cell equalization in a shorter time without affecting the normal operation of the charging task of the charging device (i.e., equalization will not cause the charging device to interrupt charging).

[0083] For example, in one possible implementation, the first equalization current can be determined according to the following formula (1), and the first equalization time can be determined according to the following formula (2):

[0084] First equalization current = (current cell charging capacity – α * charging request current) / β Formula (1);

[0085] BalTime_j = ΔSOC_out_j / First Equalization Current Formula (2);

[0086] Where α is the first coefficient and β is the second coefficient;

[0087] In some embodiments, determining the first equalizing current based on the difference may further include: determining the first equalizing current based on the ratio of the difference to a second coefficient. For example, the first equalizing current is equal to the difference divided by the second coefficient.

[0088] Step 403: Determine the current inter-pack imbalance of the first battery pack.

[0089] It is understandable that inter-pack imbalance characterizes the degree of difference in cell capacity or state of charge (SOC) distribution among multiple battery packs. In a multi-pack series structure, due to differences in manufacturing processes, usage conditions, and other factors, the SOC of each battery pack may be inconsistent, and this inconsistency is a manifestation of inter-pack imbalance.

[0090] In some embodiments, step 403 may further include the following steps one through five:

[0091] Step 1: Obtain the current status parameters of the first battery pack;

[0092] Step 2: Determine the first mapping value corresponding to the current state parameter of the first battery pack according to the pre-defined mapping relationship;

[0093] Step 3: Obtain the current status parameters of the first cell; wherein, the first cell is the cell with the lowest cell voltage in the first battery pack and the second battery pack.

[0094] Step 4: Determine the second mapping value corresponding to the current state parameter of the first cell according to the pre-calibrated mapping relationship;

[0095] Step 5: Determine the current inter-pack imbalance of the first battery pack based on the difference between the first mapping value and the second mapping value.

[0096] For example, the current inter-pack imbalance of the first battery pack is equal to the first mapping value minus the second mapping value.

[0097] In this embodiment of the application, the current state parameters of the first battery pack and the first battery cell are not limited. The current state parameters may include, but are not limited to, at least one of the following: temperature, current, voltage, and SOC.

[0098] In some embodiments, the controller 104, as the core control unit, can be responsible for collecting and analyzing state parameters such as voltage, current, and temperature of each battery pack or cell, and calculating the current imbalance between packs through a pre-calibrated mapping relationship.

[0099] For example, in one possible implementation, the controller can continuously monitor the state parameters of the battery pack and cells, such as temperature T, current I, voltage V, and SOC. When the corresponding equalization identification condition is met, the system will trigger equalization calculation, and calculate the inter-pack imbalance ΔSOC_out_j (where j is the battery pack number) of each battery pack based on the pre-calibrated mapping relationship. For example, the inter-pack imbalance ΔSOC_out_j of the j-th battery pack can be determined according to the following formula (3):

[0100] ΔSOC_out_ j= f(I_ j,V_ j,T_ j,SOH_ j)- f(I1,V1,T1,SOH1) Formula (3);

[0101] It can be understood that f(I,V,T,SOH) is the functional relationship between pre-calibrated battery state parameters (such as voltage, temperature, current, etc.) and SOC or other performance indicators. This relationship is used to convert the actually measured battery state parameters into standardized SOC or other performance indicators, facilitating subsequent processing and analysis.

[0102] In formula (3), I_j, V_j, T_j, and SOH_j represent the current current, current voltage, current temperature, and current SOH of the j-th battery pack, respectively, and f(I_j,V_j,T_j,SOH_j) is a mapping value obtained based on I_j, V_j, T_j, and SOH_j and a pre-calibrated mapping relationship. I1, V1, T1, and SOH1 represent the current current, current voltage, current temperature, and current SOH of the cell with the lowest cell voltage among all battery packs in the battery module. In one possible implementation, SOH1 can also be the SOH of the battery pack containing the cell (i.e., the SOH of the entire pack).

[0103] Step 404: Determine the first equalization time based on the current room imbalance and the first equalization current.

[0104] It is understood that in the above embodiments, the maximum charging current is determined according to the current inter-pack imbalance of the first battery pack, and the first balancing current is determined based on the minimum charging current allowed by the charging equipment and the current cell charging capacity. Therefore, in the above embodiments, the dynamic balancing current calculation method can assess the current charging capacity of the battery in real time and intelligently and dynamically adjust the balancing current to match the actual battery state. This not only effectively prevents battery overcurrent problems during balancing but also ensures the smooth progress of the entire charging process, improving the system's safety and efficiency.

[0105] Specifically, in step 404 above, the first equalization time is determined based on the current room imbalance and the first equalization current.

[0106] Furthermore, in some embodiments, step 404 may include: determining the first equalization time based on the ratio of the current inter-room imbalance to the first equalization current; wherein the first equalization time is positively correlated with the ratio.

[0107] For example, the first equalization time is equal to the ratio of the current room imbalance to the first equalization current, that is, the first equalization time is equal to the current room imbalance divided by the first equalization current. This can be expressed by formula (4) as follows:

[0108] BalTime_j = ΔSOC_out_j / First Equalization Current Formula (4);

[0109] Where BalTime_j represents the first equalization time of the j-th battery pack (i.e., the equalization duration between packs).

[0110] ΔSOC_out_j represents the inter-packet imbalance of the j-th battery pack, and the first equalization current represents the first equalization current of the j-th battery pack. The first battery pack can also be understood as the j-th battery pack, where j=1 or 2, etc.

[0111] It is understood that in the above embodiments, the first equalization time is determined based on the ratio of the current room imbalance to the first equalization current; that is, the first equalization time is adapted to the current room imbalance and the current equalization current, which is beneficial for the system to reasonably evaluate the time required for the equalization process, thereby improving the room equalization performance.

[0112] Step 302: Based on the first equalization current and the first equalization time, control the motor controller to open the circuit between the positive and negative terminals of the first battery pack so as to charge the energy of the first battery pack to the motor according to the first equalization current.

[0113] Step 303: Control the motor controller to open the circuit between the positive and negative terminals of the second battery pack so as to discharge the energy stored in the motor to the second battery pack according to the first equalization current.

[0114] It is understood that the motor has a structure with at least one phase of inductance. In this way, the energy of the first battery pack is transferred to the inductance in the motor for storage and is discharged to the second battery pack through the other end of the motor.

[0115] In some embodiments, the duty cycle of the cell equalization can be determined based on the current temperature of the battery module; and steps 302 and 303 can be executed based on the duty cycle of the cell equalization; wherein, the duty cycle of the cell equalization is negatively correlated with the current temperature of the battery module, that is: the lower the current temperature of the battery module, the larger the duty cycle of the cell equalization; the higher the current temperature of the battery module, the smaller the duty cycle of the cell equalization; in this way, cell equalization can be completed as quickly as possible while ensuring that the battery temperature does not rise sharply due to equalization.

[0116] It is understood that steps 302 and 303 are steps where the controller controls the execution of inter-packet equalization. Regarding when to perform inter-packet equalization, in one possible implementation, it is performed during the charging process of the charging device to the battery module 101, if the equalization execution conditions are met. It is understood that performing inter-packet equalization during the charging process is safer than performing it while the electric vehicle is in motion.

[0117] Furthermore, in some embodiments, if the equalization execution condition is met during the charging process of the charging device to the battery module 101, performing the inter-packet equalization may include: if the motor controller 102 is idle while the charging device is charging the battery module 101, and the equalization execution condition is met, then performing the inter-packet equalization. It can be understood that performing inter-packet equalization while the motor controller is idle (i.e., without other tasks) ensures the safety of inter-packet equalization without affecting the motor controller's execution of other tasks.

[0118] Furthermore, in some embodiments, the equalization execution condition includes at least: the current cell charging capacity is greater than or equal to a first current threshold; wherein the first current threshold is greater than or equal to the sum of the minimum charging current and the minimum equalization current allowed for inter-cell equalization.

[0119] As can be understood, as mentioned above, the current cell charging capability represents the cell charging capability under the current operating conditions. If this charging capability is too low, meaning the charging current may be too small due to inter-cell balancing, causing the charging device to interrupt charging, or the inter-cell balancing may not be possible to ensure uninterrupted charging. Based on this consideration, in the above embodiments, the prerequisite for performing inter-cell balancing during charging includes at least: the current cell charging capability is greater than or equal to a first current threshold; thus, both normal charging during charging and the execution of inter-cell balancing can be ensured.

[0120] Furthermore, in some embodiments, the load balancing execution conditions also include the following conditions:

[0121] (1) The maximum cell temperature of the battery module (i.e., the maximum temperature of all cells in the battery module) is less than or equal to the first temperature threshold.

[0122] (2) The SOC of the first battery pack is greater than or equal to the first SOC threshold and less than or equal to the second SOC threshold;

[0123] (3) The minimum cell voltage of the battery module (i.e. the minimum voltage of all cells in the battery module) is greater than or equal to the first voltage threshold and less than or equal to the second voltage threshold.

[0124] In other words, when performing cell equalization, the battery temperature should not be too high, the state of charge (SOC) should not be too high or too low, and the battery voltage should not be too high or too low; in this way, cell equalization can be performed within a safe range.

[0125] It is understandable that battery pack temperature is a key factor affecting the performance and safety of the cells inside the battery pack. When the battery pack temperature is too high, it may lead to cell expansion, electrolyte decomposition, or even thermal runaway, thereby affecting the battery pack's lifespan and safety. Conversely, when the battery pack temperature is too low, it may reduce cell activity and affect charging and discharging efficiency. Therefore, before performing inter-pack equalization, the system detects the current temperature of the first battery pack and determines whether this temperature is less than or equal to a set first temperature threshold. If the temperature of the first battery pack is higher than the first temperature threshold, the system will pause the inter-pack equalization operation to avoid potential safety issues under high-temperature conditions.

[0126] The State of Charge (SOC) of a battery pack refers to the percentage of its current remaining charge relative to its full capacity, and is a crucial parameter for measuring the pack's usable capacity. In the above embodiment, to ensure the effectiveness and safety of inter-pack balancing operations, a SOC range is set as one of the balancing execution conditions. This design aims to avoid energy transfer when the first battery pack is nearly fully charged or completely discharged, as it is highly sensitive to current changes in this state. Performing energy transfer under these conditions could easily lead to overvoltage or undervoltage risks, thereby affecting the lifespan of the first battery pack and the stability of the entire system.

[0127] Voltage is a crucial indicator of a battery pack's health and operational status. Excessive voltage fluctuations may indicate internal imbalances or suggest that certain cells are in an abnormal state. Therefore, before performing inter-pack equalization, the system detects the battery pack's voltage and determines whether it falls within a first and second voltage threshold. If the first battery pack's voltage exceeds the range defined between the first and second thresholds, the system considers it unsuitable for energy transfer and will delay or cancel the equalization task until the voltage returns to a safe range.

[0128] Furthermore, in some embodiments, the controller 104 employs a multi-layer balancing strategy. This means that inter-pack balancing is achieved through a motor controller, while intra-pack balancing is achieved by using resistors to dissipate power in cells requiring balancing. Intra-pack balancing and inter-pack balancing complement each other without interfering with each other, ensuring the efficient operation of the entire battery system.

[0129] For example, in some embodiments, in addition to performing inter-packet equalization, controller 104 is also used to perform the following steps (i.e., intra-packet equalization):

[0130] Step 1: Determine the current pack imbalance of the second cell; wherein, the second cell is any cell in the first battery pack and the second battery pack.

[0131] Step 2: Determine the second equalization current of the second battery cell;

[0132] Step 3: Determine the second equalization time based on the current imbalance within the packet and the second equalization current;

[0133] Step four: Equalize the second cell according to the second equalization current and the second equalization time.

[0134] It is understandable that when a traditional power system performs other functions, such as charging and discharging a single battery pack, the voltage distribution within the battery changes, rendering previous equalization calculations unreliable. Continuing to perform these functions would lead to incorrect equalization. Therefore, the above embodiment introduces a multi-level collaborative equalization method, including independent inter-packet equalization and intra-packet equalization methods. These two methods calculate independently, ensuring that individual charging and discharging of multiple battery packs does not interfere with the voltage distribution within the battery packs, thus guaranteeing the accuracy and reliability of the equalization results.

[0135] Specifically, in step one above, the current imbalance within the battery pack of the second cell is determined; wherein the second cell is any cell in the first battery pack and the second battery pack.

[0136] Further, in some embodiments, step one may include: obtaining the current state parameters of the second battery cell; determining a third mapping value corresponding to the current state parameters of the second battery cell according to a pre-calibrated mapping relationship; obtaining the current state parameters of the third battery cell; wherein the third battery cell is the battery cell with the lowest cell voltage in the first battery pack; determining a fourth mapping value corresponding to the current state parameters of the third battery cell according to the pre-calibrated mapping relationship; and determining the current intra-pack imbalance degree of the second battery cell according to the difference between the third mapping value and the fourth mapping value. For example, the current intra-pack imbalance degree of the second battery cell is equal to the third mapping value minus the fourth mapping value.

[0137] In this application embodiment, the current state parameters of the second and third battery cells are not limited. The current state parameters may include, but are not limited to, at least one of the following: temperature, current, voltage, and SOC.

[0138] In some embodiments, the controller 104, as the core control unit, can be responsible for collecting and analyzing state parameters such as voltage, current, and temperature of each battery pack or cell, and calculating the current pack imbalance of the second cell through a pre-calibrated mapping relationship.

[0139] For example, in one possible implementation, the controller can continuously monitor the state parameters of the battery pack and cells, such as temperature T, current I, voltage V, and SOC. When the corresponding equalization identification condition is met, the system will trigger equalization calculation, and calculate the current unbalance ΔSOC_in_i of the i-th cell in the pack based on the pre-calibrated mapping relationship (i is the cell number, that is, each cell has its own ΔSOC_in). For example, the current unbalance ΔSOC_in_i of the i-th cell in the pack can be determined according to the following formula (5):

[0140] ΔSOC_in_i= f(I_i,V_i,T_i,SOH_i)- f(I2,V2,T2,SOH2) Formula (5);

[0141] It can be understood that f(I,V,T,SOH) is the functional relationship between pre-calibrated battery state parameters (such as voltage, temperature, current, etc.) and SOC or other performance indicators. This relationship is used to convert the actually measured battery state parameters into standardized SOC or other performance indicators, facilitating subsequent processing and analysis.

[0142] In formula (5), I_i, V_i, T_i, and SOH_i represent the current current, current voltage, current temperature, and current SOH of the i-th cell, respectively. f(I_i,V_i,T_i,SOH_i) is a mapping value obtained based on I_i, V_i, T_i, and SOH_i and a pre-calibrated mapping relationship. I2, V2, T2, and SOH2 represent the current current, current voltage, current temperature, and current SOH of the cell with the lowest cell voltage in the battery pack containing the i-th cell, respectively.

[0143] In step four above, the second battery cell is balanced according to the second balancing current and the second balancing time. Furthermore, in some embodiments, the power consumption of the second battery cell can be controlled by the balancing resistor connected to the second battery cell, thereby achieving in-packet balancing.

[0144] Specifically, in step two above, the second equalization current of the second battery cell is determined; furthermore, in some embodiments, step two may include determining the second equalization current of the second battery cell based on the average voltage of the battery cell and the resistance value of the equalization resistor connected to the second battery cell.

[0145] In one possible implementation, the average voltage of the battery cell is pre-calibrated.

[0146] Specifically, in step three above, the second balancing time is determined based on the current intra-packet imbalance and the second balancing current. Further, in some embodiments, step three may include determining the second balancing time based on the ratio of the current intra-packet imbalance to the second balancing current. For example, the second balancing time is equal to the current intra-packet imbalance divided by the second balancing current.

[0147] The following examples illustrate possible implementation schemes for one or more of the above embodiments.

[0148] In a Battery Management System (BMS), balancing should ensure that the minimum cell capacity is utilized. To avoid ineffective capacity release caused by inconsistent State of Charge (SOC) and self-discharge rates among cells at the manufacturing stage, BMS typically incorporates balancing control to ensure that the SOC of each cell is consistent. However, the lack of resting opportunities and reduced full-charge opportunities for LFP cells makes it difficult to identify imbalances. NCM cells rely on resting conditions, and identifying imbalances through OCV (Optical Characteristic Voltage) introduces errors. Therefore, BMS needs to implement balancing control at the charging end based on the charging curve of the largest single-cell voltage. For example, in related technologies, battery balancing methods include: calculating the remaining capacity of each cell based on its voltage; using the average of the minimum remaining capacity and the average remaining capacity as the balancing target; and calculating the required balancing time for each cell based on the difference between the remaining capacity and the balancing target, as well as the effective current of the balancing circuit, thus converting it into balancing control commands.

[0149] However, during battery manufacturing, variations in State of Charge (SOC) due to process factors mainly manifest in two aspects: inconsistent SOC at the time of cell production and inconsistent self-discharge coefficients. These differences in SOC, both at the time of production and during use, affect the overall capacity of the battery. Incorporating equalization control management into battery packs ensures that the SOC of each cell reaches a consistent level, facilitating control of the battery's depth of charge and discharge, preventing overcharging and over-discharging, thereby improving the battery's usable capacity and safety, extending its lifespan, and ultimately enhancing overall performance.

[0150] For battery structures with multiple battery packs connected in series, since other functions of the BMS will perform independent charging and discharging operations on the two battery packs, the existing equalization algorithm will not be reliable in calculating the equalization time required for each individual cell under this battery structure, which will lead to incorrect equalization.

[0151] In this application embodiment, a multi-level collaborative balancing method based on an electric drive system (i.e., a power system) is provided. By adding a motor controller between multiple battery packs to control the energy transfer between the multiple battery packs, inter-pack balancing is achieved, and collaborative independent intra-pack balancing is achieved, thereby improving the consistency level of the cells in the series-connected batteries.

[0152] (1) An energy transfer equalization method based on an electric drive system is proposed. By using a built-in motor controller as an energy regulator, the energy flow between multiple battery packs can be precisely controlled, and the energy in any battery pack can be transferred to another battery pack (including transferring energy from a high-voltage pack to a low-voltage pack / transferring energy from a low-voltage pack to a high-voltage pack). By transferring energy through the motor controller, the voltage or capacity difference between battery packs can be eliminated, which significantly improves the overall balance between battery packs and makes the performance of battery packs more consistent, thereby enhancing the stability and working efficiency of the entire battery system.

[0153] (2) A multi-level collaborative balancing method is proposed, which not only focuses on the balance between battery packs, but also takes into account the balance of each individual cell within the battery pack. The cells within the battery pack are balanced using balancing resistors for power consumption, and the power transfer between battery packs is controlled by a motor controller. Through the synergistic effect of inter-pack balancing and intra-pack balancing, the consistency level of all individual cells is improved.

[0154] (3) A dynamic equalization current calculation method is proposed. By intelligently identifying the battery charging status and the charging pile capacity, the optimal equalization current is accurately calculated to achieve efficient and accurate battery equalization. Under the premise of ensuring the safety and reliability of the charging process, the equalization capability is improved.

[0155] (4) The proposed equalization method is applied to the battery equalization strategy of multi-cell series connection to form a multi-level equalization solution. Its application can improve the overall performance and reliability of the battery pack, effectively prevent the vehicle performance degradation caused by low cell consistency, effectively prevent breakdowns, and ensure the stable operation of electric vehicles and the safety of drivers.

[0156] It is understandable that traditional battery management systems (BMS), when performing other functions such as charging and discharging individual battery packs, can cause changes in the voltage distribution within the batteries, rendering previous equalization calculations unreliable. Continuing to execute these functions would lead to erroneous equalization. However, this application introduces a unique multi-level collaborative equalization method, including independent inter-pack equalization and intra-pack equalization methods. These two methods calculate independently, and when multiple battery packs are individually charged and discharged, they do not interfere with the voltage distribution within the battery packs, thus ensuring the accuracy and reliability of the equalization results.

[0157] It is understandable that traditional BMS cannot perform balancing operations after power-off, and passenger vehicles typically have limited daily driving time, which may lead to the algorithm failing to identify battery pack imbalances in time, resulting in insufficient balancing capabilities. This invention features an innovative inter-pack balancing current design, using an electric drive system to perform energy transfer between multiple battery packs, with current reaching hundreds of amps, significantly improving battery pack balancing efficiency, thereby ensuring the overall performance of the battery pack and the lifespan of the batteries.

[0158] It is understandable that activating the inter-pack energy transfer function during charging may pose a risk of battery pack overcurrent, which not only threatens battery life but also affects the stability and safety of the charging process. This application utilizes a dynamic balancing current calculation method to assess the battery's current charging capacity in real time and intelligently adjust the balancing current dynamically to match the actual charging request current. This effectively prevents battery overcurrent issues, ensures the smooth progress of the entire charging process, and improves system safety and efficiency.

[0159] In traditional battery management systems (BMS), balancing control is performed to ensure that the battery pack fully utilizes its minimum cell capacity, eliminating the impact of poor initial cell consistency and self-discharge differences. However, in current multi-cell pack structures, other functions of the BMS result in independent charging and discharging operations for each cell pack. This makes the balancing time calculated by existing balancing algorithms for each individual cell unreliable when dealing with this battery structure, potentially leading to incorrect balancing decisions.

[0160] To address this issue, this application proposes a multi-level collaborative balancing technology solution based on an electric drive system:

[0161] (1) A multi-level balancing strategy is adopted. The balancing is first performed independently within the battery pack, and the power consumption of the cells that need to be balanced is reduced by the balancing resistor. Multiple battery packs transfer energy through the electric drive system to achieve mutual balance between the packs. The balancing within the pack and the balancing between the packs complement each other and do not interfere with each other, ensuring the efficient operation of the entire battery system.

[0162] (2) Monitor battery status parameters in real time, including temperature T, current I, voltage V, and SOC. When the corresponding equalization identification condition is met, trigger equalization calculation. Calculate the intra-pack imbalance ΔSOC_in_i (where i is the cell number, i.e., each cell has its own ΔSOC_in) and inter-pack imbalance ΔSOC_out_j (where j is the battery pack number, i.e., each battery pack has its own ΔSOC_out) based on the voltage of all cells. The intra-pack imbalance calculation is based on the minimum cell voltage within the pack, calculates the equalization time, and stores the data. The goal of the inter-pack imbalance calculation is to ensure that the minimum cell voltage of each battery pack remains consistent.

[0163] The calculation method is to calculate the inter-pack imbalance and intra-pack imbalance by constructing a mapping relationship based on the parameter information calibrated during battery design. See formula (1) and formula (5) mentioned above for details. After calculating the corresponding imbalance, the equalization time of each cell is stored in the storage medium.

[0164] (3) Continuously monitor battery status. As long as the BMS is powered on, battery pack equalization can be performed, and the stored ΔSOC is updated according to the equalization execution time.

[0165] The remaining equalization time BalTime_i within the package is calculated using the following formula (where i is the cell number):

[0166] BalTime_i = ΔSOC_in_i / Balancing current

[0167] Battery pack balancing is performed during charging. When the motor controller has no other tasks, it determines whether the battery pack meets the conditions for energy transfer (e.g., temperature should not be too high, SOC should not be too high / low, etc.). If the balancing conditions are met, battery pack balancing is performed. Based on the cell charging capacity under current operating conditions, the battery pack balancing current, charging request current, and balancing duration are dynamically calculated and transmitted to the electric drive system, which controls the energy transfer between battery packs. The stored ΔSOC is updated according to the balancing execution time.

[0168] The remaining equalization time for each battery pack (BalTime_j) is calculated using the following formula (j is the battery pack number):

[0169] Equalization current = (Current cell charging capacity – α * charging request current) / β;

[0170] BalTime_j = ΔSOC_out_j / equalization current;

[0171] The above methods enable more precise SOC consistency, thereby improving the overall performance and lifespan of the battery pack. In summary, this novel balancing strategy for collaborative electric drive systems effectively solves the balancing problem caused by BMS functions in multi-battery pack structures, improving the performance and stability of the battery pack.

[0172] Figure 6 A schematic flowchart of a multi-level collaborative balancing method based on an electric drive system is provided for embodiments of this application; as shown below. Figure 6 As shown, the method includes the following steps 601 to 611:

[0173] Step 601: BMS monitors battery status;

[0174] Step 602: Determine whether a load balancing calculation has been triggered; if yes, proceed to step 603; otherwise, return to step 601.

[0175] Step 603: Calculate and store the first and second equilibrium times;

[0176] Step 604: Determine whether intra-packet load balancing is allowed; if yes, proceed to step 605; otherwise, return to step 604.

[0177] Step 605: Perform equalization control based on the second equalization time;

[0178] Step 606: Update the stored second equalization time;

[0179] Step 607: Determine whether room balance is allowed; if yes, proceed to step 608; otherwise, return to step 607.

[0180] Step 608: Calculate the charging request current and the second equalization current;

[0181] Step 609: Perform equalization control based on the first equalization time;

[0182] Step 610: Update the first equalization time of the storage;

[0183] Step 611: Determine whether to enter the power-down state based on the updated first and second equalization times; if yes, end; otherwise, return to step 601.

[0184] Based on the same inventive concept as the foregoing embodiments, this application provides a battery balancing method. Figure 3 This is a schematic diagram illustrating the implementation process of the battery balancing method provided in the embodiments of this application; as follows: Figure 3 As shown, the method includes the following steps 301 to 303:

[0185] Step 301: Determine the first equalization current and the first equalization time of the first battery pack in the battery module based on the current state parameters of the battery module; wherein the battery module includes at least the first battery pack and a second battery pack connected in series with the first battery pack;

[0186] Step 302: Based on the first equalization current and the first equalization time, control the motor controller to open the circuit between the positive and negative terminals of the first battery pack, so as to charge the energy of the first battery pack to the motor according to the first equalization current;

[0187] Step 303: Control the motor controller to open the circuit between the positive and negative terminals of the second battery pack, so as to discharge the energy stored in the motor to the second battery pack according to the first equalization current.

[0188] Steps 302 and 303 can be understood as steps to perform inter-packet equalization. In some embodiments, during the charging process of the battery module by the charging device, if the equalization execution conditions are met, the inter-packet equalization is performed (i.e., steps 302 and 303 are executed).

[0189] In other embodiments, while the charging device is charging the battery module and the motor controller is in an idle state, if the equalization execution condition is met, the inter-packet equalization is performed (i.e., steps 302 and 303 are executed).

[0190] In some embodiments, the method further includes: determining the current intra-pack imbalance of the second cell; wherein the second cell is any cell in the first battery pack and the second battery pack; determining a second balancing current of the second cell; determining a second balancing time based on the current intra-pack imbalance and the second balancing current; and balancing the second cell based on the second balancing current and the second balancing time.

[0191] Further, in some embodiments, determining the current intra-pack imbalance of the second battery cell includes: obtaining the current state parameters of the second battery cell; determining a third mapping value corresponding to the current state parameters of the second battery cell according to a pre-calibrated mapping relationship; obtaining the current state parameters of the third battery cell; wherein the third battery cell is the battery cell with the lowest cell voltage in the first battery pack; determining a fourth mapping value corresponding to the current state parameters of the third battery cell according to the pre-calibrated mapping relationship; and determining the current intra-pack imbalance of the second battery cell according to the difference between the third mapping value and the fourth mapping value.

[0192] It should be noted that although the steps of the method in this application are described in a specific order in the accompanying drawings, this does not require or imply that the steps must be performed in that specific order, or that all the steps shown must be performed to achieve the desired result. Additional or alternative steps may be omitted, multiple steps may be combined into one step, and / or one step may be broken down into multiple steps; or steps from different embodiments may be combined into a new technical solution.

[0193] The description of the above method embodiments is similar to that of the above power system embodiments, and has similar beneficial effects. For technical details not disclosed in the method embodiments of this application, please refer to the description of the power system embodiments of this application for understanding.

[0194] It should be noted that, in the embodiments of this application, if the above-described methods are implemented as software functional modules and sold or used as independent products, they can also be stored in a computer-readable storage medium. Based on this understanding, the technical solutions of the embodiments of this application, or the parts that contribute to related technologies, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause an electronic device to execute all or part of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), magnetic disks, or optical disks. Thus, the embodiments of this application are not limited to any specific hardware and software combination.

[0195] This application provides an electric vehicle. Figure 7 This is a schematic diagram of the structure of an electric vehicle provided in an embodiment of this application; as shown below. Figure 7 As shown, the electric vehicle 700 includes a body body 701 and a power system 100 as described in one or more of the above embodiments.

[0196] This application also provides a computer-readable storage medium for storing computer programs.

[0197] Optionally, the computer-readable storage medium can be applied to the electronic device in the embodiments of this application, and the computer program causes the controller or electric vehicle to perform the various methods of the embodiments of this application, which will not be described in detail here for the sake of brevity.

[0198] This application also provides a computer program product, including computer program instructions.

[0199] Optionally, the computer program product can be applied to the electronic device in the embodiments of this application, and the computer program instructions cause the controller or electric vehicle to perform the various methods of the embodiments of this application. For the sake of brevity, they will not be described in detail here.

[0200] This application also provides a computer program.

[0201] Optionally, the computer program can be applied to the electronic device in the embodiments of this application. When the computer program runs on the controller or electric vehicle, it causes the controller or electric vehicle to execute the various methods in the embodiments of this application. For the sake of brevity, these will not be described in detail here.

[0202] It should be noted that the descriptions of the electric vehicles, storage media, computer program products, and computer program embodiments above are similar to the descriptions of the method embodiments above, and have similar beneficial effects. For technical details not disclosed in the electric vehicles, storage media, computer program products, and computer program embodiments of this application, please refer to the descriptions of the method embodiments of this application for understanding.

[0203] It should be understood that the phrases "one embodiment," "an embodiment," or "some embodiments" mentioned throughout the specification mean that a specific feature, structure, or characteristic related to an embodiment is included in at least one embodiment of this application. Therefore, "in one embodiment," "in one embodiment," or "in some embodiments" appearing throughout the specification do not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. It should be understood that in the various embodiments of this application, the sequence numbers of the above-described processes do not imply a sequential order of execution; the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application. The sequence numbers of the above-described embodiments are merely for descriptive purposes and do not represent the superiority or inferiority of the embodiments. The descriptions of the various embodiments above tend to emphasize the differences between the various embodiments; their similarities or commonalities can be referred to mutually, and for the sake of brevity, they will not be repeated here.

[0204] In this article, the term "and / or" is merely a description of the relationship between related objects, indicating that there can be three kinds of relationships. For example, object A and / or object B can represent three situations: object A exists alone, object A and object B exist simultaneously, and object B exists alone.

[0205] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0206] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. The embodiments described above are merely illustrative. For example, the division of modules is only a logical functional division, and in actual implementation, there may be other division methods, such as: multiple modules or components can be combined, or integrated into another system, or some features can be ignored or not executed. In addition, the coupling, direct coupling, or communication connection between the various components shown or discussed can be through some interfaces, and the indirect coupling or communication connection between devices or modules can be electrical, mechanical, or other forms.

[0207] The modules described above as separate components may or may not be physically separate. The components shown as modules may or may not be physical modules. They may be located in one place or distributed across multiple network units. Some or all of the modules may be selected to achieve the purpose of this embodiment according to actual needs.

[0208] In addition, each functional module in the various embodiments of this application can be integrated into one processing unit, or each module can be a separate unit, or two or more modules can be integrated into one unit; the integrated modules can be implemented in hardware or in the form of hardware plus software functional units.

[0209] Those skilled in the art will understand that all or part of the steps of the above method embodiments can be implemented by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When the program is executed, it performs the steps of the above method embodiments. The aforementioned storage medium includes various media that can store program code, such as mobile storage devices, read-only memory (ROM), magnetic disks, or optical disks.

[0210] Alternatively, if the integrated units described above are implemented as software functional modules and sold or used as independent products, they can also be stored in a computer-readable storage medium. Based on this understanding, the technical solutions of the embodiments of this application, or the parts that contribute to related technologies, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause an electronic device to execute all or part of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as mobile storage devices, ROMs, magnetic disks, or optical disks.

[0211] The methods disclosed in the several method embodiments provided in this application can be arbitrarily combined without conflict to obtain new method embodiments.

[0212] The features disclosed in the several product embodiments provided in this application can be arbitrarily combined without conflict to obtain new product embodiments.

[0213] The features disclosed in the several method or device embodiments provided in this application can be arbitrarily combined without conflict to obtain new method or device embodiments.

[0214] The above description is merely an embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. A power system, characterized in that, The system includes: a controller, a motor controller, a motor, and a battery module. The battery module includes at least a first battery pack and a second battery pack connected in series with the first battery pack. The controller is connected to the motor controller, and the motor is connected between the motor controller and the battery module. The controller is used for: The current cell charging capability of the battery module is determined based on the current state parameters of multiple cells in the battery module; wherein the current state parameters of the cells include at least one of the following: SOC, temperature, and voltage; A first equalization current is determined based on the minimum charging current allowed by the charging device and the current charging capacity of the battery cell. Obtain the current status parameters of the first battery pack; Based on the pre-defined mapping relationship, determine the first mapping value corresponding to the current state parameter of the first battery pack; Obtain the current state parameters of the first battery cell; wherein, the first battery cell is the battery cell with the lowest cell voltage in the first battery pack and the second battery pack; Based on the pre-calibrated mapping relationship, determine the second mapping value corresponding to the current state parameters of the first cell; The current inter-pack imbalance of the first battery pack is determined based on the difference between the first mapping value and the second mapping value. The first equalization time is determined based on the current imbalance of the private room and the first equalization current. Performing inter-packet balancing, the inter-packet balancing includes: controlling the motor controller to open the circuit between the positive and negative terminals of the first battery pack according to the first balancing current and the first balancing time, so as to charge the motor with the energy of the first battery pack according to the first balancing current; and, The motor controller is controlled to open the circuit between the positive and negative terminals of the second battery pack, so as to discharge the energy stored in the motor to the second battery pack according to the first equalization current.

2. The power system according to claim 1, characterized in that, Determining the current cell charging capability of the battery module based on the current state parameters of multiple cells in the battery module includes: Based on the current state parameters of the i-th cell in the battery module, determine the maximum charging current that the charging device is currently allowed to provide to the i-th cell; where i is greater than or equal to 1. The current cell charging capability of the battery module is determined based on the minimum value among the maximum charging currents of the multiple cells.

3. The power system according to claim 2, characterized in that, Determining the current cell charging capability of the battery module based on the minimum value among the maximum charging currents of the plurality of cells includes: The current cell charging capacity of the battery module is equal to the minimum value among the maximum charging currents of all cells in the battery module.

4. The power system according to claim 1, characterized in that, Determining the first equalization time based on the current room imbalance and the first equalization current includes: The first equalization time is determined based on the ratio of the current room imbalance to the first equalization current; wherein the first equalization time is positively correlated with the ratio.

5. The power system according to claim 4, characterized in that, The first equalization time is equal to the ratio of the current room imbalance to the first equalization current.

6. The power system according to claim 1, characterized in that, Determining the first equalization current based on the minimum charging current allowed by the charging device and the current cell charging capability includes: Based on the minimum charging current allowed by the charging device, a charging request current is determined; wherein, the charging request current refers to the charging current requested by the charging device, and the charging request current is greater than or equal to the minimum charging current; The first equalization current is determined based on the current cell charging capacity and the charging request current.

7. The power system according to claim 6, characterized in that, Determining the first equalization current based on the current cell charging capacity and the charging request current includes: Determine the product of the charging request current and a preset first coefficient; The first equalization current is determined based on the difference between the current cell charging capacity and the product; wherein the first equalization current is positively correlated with the difference.

8. The power system according to any one of claims 1-7, characterized in that, The execution of packet balancing includes: During the charging process of the charging device for the battery module, if the equalization execution conditions are met, the inter-packet equalization is performed.

9. The power system according to claim 8, characterized in that, During the charging process of the battery module by the charging device, if the equalization execution conditions are met, the inter-packet equalization is performed, including: While the charging device is charging the battery module and the motor controller is in an idle state, if the equalization execution condition is met, the inter-packet equalization is performed.

10. The power system according to claim 8, characterized in that, The equalization execution conditions include at least the following: the current cell charging capacity is greater than or equal to a first current threshold; wherein the first current threshold is greater than or equal to the sum of the minimum charging current and the minimum equalization current allowed for inter-cell equalization.

11. The power system according to claim 10, characterized in that, The conditions for balanced execution also include: The maximum cell temperature of the battery module is less than or equal to a first temperature threshold. The SOC of the first battery pack is greater than or equal to the first SOC threshold and less than or equal to the second SOC threshold; The minimum cell voltage of the battery module is greater than or equal to a first voltage threshold and less than or equal to a second voltage threshold.

12. The power system according to any one of claims 1-7, characterized in that, The controller is also used for: Determine the current intra-pack imbalance of the second cell; wherein the second cell is any cell in the first battery pack and the second battery pack; The second equalization current of the second battery cell is determined based on the average voltage of the battery cell and the resistance value of the equalization resistor connected to the second battery cell. The second equalization time is determined based on the current imbalance within the packet and the second equalization current. The second cell is balanced according to the second balancing current and the second balancing time; The determination of the current intra-pack imbalance of the second cell includes: Obtain the current status parameters of the second battery cell; Based on the pre-defined mapping relationship, determine the third mapping value corresponding to the current state parameters of the second cell; Obtain the current state parameters of the third cell; wherein the third cell is the cell with the lowest cell voltage in the first battery pack; Based on the pre-calibrated mapping relationship, determine the fourth mapping value corresponding to the current state parameters of the third cell; The current intra-pack imbalance of the second cell is determined based on the difference between the third mapping value and the fourth mapping value.

13. A battery balancing method, characterized in that, The method includes: The current cell charging capability of the battery module is determined based on the current state parameters of multiple cells in the battery module; wherein the battery module includes at least a first battery pack and a second battery pack connected in series with the first battery pack; the current state parameters of the cells include at least one of the following: SOC, temperature, and voltage; A first equalization current is determined based on the minimum charging current allowed by the charging device and the current charging capacity of the battery cell. Obtain the current status parameters of the first battery pack; Based on the pre-defined mapping relationship, determine the first mapping value corresponding to the current state parameter of the first battery pack; Obtain the current state parameters of the first battery cell; wherein, the first battery cell is the battery cell with the lowest cell voltage in the first battery pack and the second battery pack; Based on the pre-calibrated mapping relationship, determine the second mapping value corresponding to the current state parameters of the first cell; The current inter-pack imbalance of the first battery pack is determined based on the difference between the first mapping value and the second mapping value. The first equalization time is determined based on the current imbalance of the private room and the first equalization current. Performing inter-packet equalization, the inter-packet equalization comprising: controlling the motor controller to open the circuit between the positive and negative terminals of the first battery pack according to the first equalization current and the first equalization time, so as to charge the motor with the energy of the first battery pack according to the first equalization current; and, The motor controller is controlled to open the circuit between the positive and negative terminals of the second battery pack connected in series with the first battery pack, so as to discharge the energy stored in the motor to the second battery pack according to the first equalization current.

14. An electric vehicle, characterized in that, The electric vehicle includes a vehicle body and a power system as described in any one of claims 1 to 12.

15. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the controller or electric vehicle, it implements the method as described in claim 13.

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