Current control method, system, apparatus, computer program product, and storage medium

Abstract

The present disclosure relates to a current control method, system, device, computer program product and storage medium, and relates to the field of battery management. The current control method is applied to a battery management system, and includes: during charging of a multi-branch battery, calculating a maximum difference between states of charge of different branch batteries according to states of charge of each branch battery in the multi-branch battery; according to a comparison result of the maximum difference and a first charging threshold, adopting a charging current distribution mode corresponding to the comparison result to distribute the charging current to determine a distribution current of each branch battery; determining a requested charging current of each branch battery according to an actual charging current and the distribution current of each branch battery; and instructing a voltage conversion unit of each branch battery to adjust the actual charging current according to the requested charging current. During the battery charging process, the charging current is adjusted to achieve balanced control of the SOC of different branch batteries.

Description

Technical Field

[0001] This disclosure relates to the field of battery management, and in particular to a current control method, a current control system, a current control device, a computer program product, and a computer-readable storage medium. Background Technology

[0002] The actual usable capacity of a multi-branch battery is related to the state of charge (SOC) of each branch battery. When the SOC of different branch batteries deviates significantly over a long period, the degradation of the different branch batteries is inconsistent, leading to a decrease in the actual usable capacity of the multi-branch battery. For example, when a multi-branch battery is used as the power battery of a vehicle, a decrease in the actual usable capacity of the multi-branch battery will shorten the vehicle's driving range.

[0003] In related technologies, the output power reference value is adjusted according to the SOC of different branch batteries in order to reduce the deviation between the SOCs of different branch batteries. Summary of the Invention

[0004] The inventors of this disclosure have discovered the following problem in the above-mentioned related technologies: the SOC deviation of different branches of a multi-branch battery is large at the end of charging, which leads to a decrease in the actual usable capacity of the multi-branch battery.

[0005] In view of this, this disclosure proposes a current control technology solution, which balances the SOC of different branches of the battery during the charging process of the multi-branch battery, reduces the SOC deviation of different branches of the battery at the end of charging, slows down the degradation of the multi-branch battery, and delays the decrease in the actual usable capacity of the multi-branch battery.

[0006] According to some embodiments of this disclosure, a current control method is provided, applied to a Battery Management System (BMS), comprising: during the charging process of a multi-branch battery, calculating the maximum difference between the SOCs of different branch batteries based on the SOC corresponding to each branch battery in the multi-branch battery; based on the comparison result of the maximum difference with a first charging threshold, distributing the charging current according to a charging current distribution method corresponding to the comparison result, thereby determining the distribution current of each branch battery; determining the requested charging current of each branch battery based on the actual charging current and the distribution current of each branch battery; and instructing the voltage conversion unit of each branch battery to adjust the actual charging current according to the requested charging current.

[0007] In some embodiments, based on the comparison result of the maximum difference and the first charging threshold, a charging current allocation method corresponding to the comparison result is adopted to allocate the charging current to determine the allocated current of each branch battery, including: in response to the maximum difference being greater than the first charging threshold, adopting a first charging current allocation method, the first charging current allocation method including: identifying the branch battery in each branch battery whose SOC difference from the maximum SOC is greater than the first charging threshold as the first branch battery, the maximum SOC being the maximum value of the SOC of each branch battery; determining the first allocated current of the first branch battery based on the charging current and the maximum allowable charging current of the first branch battery, the maximum allowable charging current being determined based on the SOC and temperature state information of the first branch battery.

[0008] In some embodiments, determining the first distribution current of the first branch battery based on the charging current and the maximum allowable charging current of the first branch battery includes: distributing the charging current equally according to the number of first branch batteries to obtain a first pre-average distribution current of the first branch battery; and determining the smaller value between the first pre-average distribution current and the maximum allowable charging current of the first branch battery as the first distribution current of the first branch battery.

[0009] In some embodiments, the first charging current allocation method includes: in response to the first allocation current being less than the charging current, determining the remaining charging current based on the charging current and the first allocation current; and for the second branch battery other than the first branch battery in the multi-branch battery, distributing the remaining charging current equally according to the number of the second branch batteries to obtain the second allocation current of the second branch battery.

[0010] In some embodiments, based on the comparison result of the maximum difference and the first charging threshold, a charging current allocation method corresponding to the comparison result is adopted to allocate the charging current, including: in response to the time for allocation according to the first charging current allocation method exceeding the charging time threshold, determining whether the maximum difference is less than the second charging threshold, wherein the second charging threshold is less than the first charging threshold; in response to the maximum difference not being less than the second charging threshold, continuing to adopt the first charging current allocation method; in response to the maximum difference being less than the second charging threshold, adopting the second charging current allocation method, wherein the second charging current allocation method is different from the first charging current allocation method.

[0011] In some embodiments, based on the comparison result of the maximum difference and the first charging threshold, a charging current allocation method corresponding to the comparison result is adopted to allocate the charging current, including: in response to the maximum difference being less than or equal to the first charging threshold, a second charging current allocation method is adopted, the second charging current allocation method including: based on the number of branch batteries in the multi-branch battery, the charging current is evenly allocated to obtain a second pre-average allocation current; based on the second pre-average allocation current and the maximum allowable charging current of the branch battery, the allocation current of each branch battery is determined, the maximum allowable charging current is determined based on the SOC and temperature state information of each branch battery.

[0012] In some embodiments, determining the requested charging current of each branch battery based on the actual charging current and the distribution current of each branch battery includes: compensating the distribution current using the difference between the actual charging current and the maximum allowable charging current of the branch battery to obtain the requested charging current of each branch battery.

[0013] In some embodiments, during the discharge process of multiple branch batteries, the maximum allowable discharge current of each branch battery is determined based on the SOC and temperature state information of each branch battery; and the voltage conversion unit of each branch battery is instructed to adjust the actual discharge current of each branch battery according to the SOC and the maximum allowable discharge current.

[0014] According to some other embodiments of this disclosure, a current control method is provided for a voltage conversion unit, comprising: during the discharge process of a multi-branch battery, calculating the maximum difference between the SOCs of different branch batteries based on the SOC corresponding to each branch battery in the multi-branch battery; and, based on the comparison result of the maximum difference with a first discharge threshold, distributing the required discharge current according to a discharge current distribution method corresponding to the comparison result, so as to determine the actual discharge current of each branch battery.

[0015] In some embodiments, based on the comparison result of the maximum difference and the first discharge threshold, a discharge current allocation method corresponding to the comparison result is adopted to allocate the required discharge current, including: in response to the maximum difference being greater than the first discharge threshold, a first discharge current allocation method is adopted, the first discharge current allocation method including: determining the actual discharge current according to the order of the SOC of each branch battery from high to low, based on the required discharge current and the maximum allowable discharge current of each branch battery, the maximum allowable discharge current being determined based on the SOC and temperature state information of each branch battery.

[0016] In some embodiments, based on the comparison result of the maximum difference and the first discharge threshold, a discharge current allocation method corresponding to the comparison result is adopted to allocate the required discharge current, including: in response to the time for allocation according to the first discharge current allocation method exceeding the discharge time threshold, determining whether the maximum difference is less than the second discharge threshold, wherein the second discharge threshold is less than the first discharge threshold; in response to the maximum difference not being less than the second discharge threshold, continuing to adopt the first discharge current allocation method; in response to the maximum difference being less than the second discharge threshold, adopting the second discharge current allocation method, wherein the second discharge current allocation method is different from the first discharge current allocation method.

[0017] In some embodiments, based on the comparison result of the maximum difference and the first discharge threshold, a discharge current allocation method corresponding to the comparison result is adopted to allocate the required discharge current, including: in response to the maximum difference being less than or equal to the first discharge threshold, a second discharge current allocation method is adopted, the second discharge current allocation method including: based on the number of branch batteries in the multi-branch battery, the required discharge current is evenly allocated to obtain a pre-average allocation current; based on the smaller of the pre-average allocation current and the maximum allowable discharge current of the branch battery, the actual discharge current of each branch battery is determined, the maximum allowable discharge current is determined based on the SOC and temperature state information of each branch battery.

[0018] According to further embodiments of this disclosure, a current control system is provided, comprising: a BMS for executing the current control method applied to the BMS in any of the above embodiments; and a voltage conversion unit for executing the current control method applied to the voltage conversion unit in any of the above embodiments.

[0019] According to further embodiments of this disclosure, a current control device is provided, configured in a BMS, comprising: a calculation unit, configured to calculate, during the charging process of a multi-branch battery, the maximum difference between the SOCs of different branch batteries based on the SOC corresponding to each branch battery in the multi-branch battery; an allocation unit, configured to allocate the charging current according to a comparison result of the maximum difference and a first charging threshold, adopting a charging current allocation method corresponding to the comparison result, to determine the allocated current of each branch battery; a determination unit, configured to determine the requested charging current of each branch battery based on the actual charging current and the allocated current of each branch battery; and an indication unit, configured to instruct the voltage conversion unit of each branch battery to adjust the actual charging current according to the requested charging current.

[0020] In some embodiments, the allocation unit is configured to adopt a first charging current allocation method in response to the maximum difference being greater than the first charging threshold. The first charging current allocation method includes: identifying the branch battery in each branch battery whose SOC difference from the maximum SOC is greater than the first charging threshold as the first branch battery, wherein the maximum SOC is the maximum value of the SOC of each branch battery; determining a first allocation current for the first branch battery based on the charging current and the maximum allowable charging current of the first branch battery, wherein the maximum allowable charging current is determined based on the SOC and temperature state information of the first branch battery.

[0021] In some embodiments, the allocation unit is configured to distribute the charging current equally according to the number of the first branch batteries to obtain a first pre-average allocation current for the first branch batteries; and to determine the smaller value between the first pre-average allocation current and the maximum allowable charging current of the first branch batteries as the first allocation current for the first branch batteries.

[0022] In some embodiments, the allocation unit is configured to, in response to the first allocation current being less than the charging current, determine a remaining charging current based on the charging current and the first allocation current; and to, for the second branch battery (excluding the first branch battery) in the multi-branch battery, to evenly distribute the remaining charging current according to the number of the second branch batteries to obtain a second allocation current for the second branch battery.

[0023] In some embodiments, the allocation unit is configured to, in response to the time for allocation according to the first charging current allocation method exceeding a charging time threshold, determine whether the maximum difference is less than a second charging threshold, wherein the second charging threshold is less than the first charging threshold; in response to the maximum difference not being less than the second charging threshold, continue to adopt the first charging current allocation method; and in response to the maximum difference being less than the second charging threshold, adopt a second charging current allocation method, wherein the second charging current allocation method is different from the first charging current allocation method.

[0024] In some embodiments, the allocation unit is configured to adopt a second charging current allocation method in response to the maximum difference being less than or equal to the first charging threshold. The second charging current allocation method includes: distributing the charging current evenly according to the number of branch batteries in the multi-branch battery to obtain a second pre-average allocation current; and determining the allocation current of each branch battery according to the second pre-average allocation current and the maximum allowable charging current of the branch battery, wherein the maximum allowable charging current is determined based on the SOC and temperature state information of each branch battery.

[0025] In some embodiments, the determining unit is configured to compensate the allocated current using the difference between the actual charging current and the maximum allowable charging current of the branch battery, to obtain the requested charging current for each branch battery.

[0026] In some embodiments, the determining unit is configured to determine the maximum allowable discharge current of each branch battery based on the SOC and temperature state information of each branch battery during the discharge process of the multiple branch batteries; the indicating unit is configured to instruct the voltage conversion unit of each branch battery to adjust the actual discharge current of each branch battery based on the SOC and the maximum allowable discharge current.

[0027] According to further embodiments of the present disclosure, a current control device is provided, configured in a voltage conversion unit, comprising: a calculation unit configured to calculate, during the discharge process of multiple branch batteries, the maximum difference between the SOCs of different branch batteries based on the SOC corresponding to each branch battery in the multiple branch batteries; and an allocation unit configured to allocate the required discharge current according to a discharge current allocation method corresponding to the comparison result of the maximum difference and a first discharge threshold, thereby determining the actual discharge current of each branch battery.

[0028] In some embodiments, the allocation unit is configured to adopt a first discharge current allocation method in response to the maximum difference being greater than the first discharge threshold. The first discharge current allocation method includes: determining the actual discharge current according to the order of the SOC of each branch battery from high to low, based on the required discharge current and the maximum allowable discharge current of each branch battery, wherein the maximum allowable discharge current is determined based on the SOC and temperature state information of each branch battery.

[0029] In some embodiments, the allocation unit is configured to, in response to the time for allocation according to the first discharge current allocation method exceeding a discharge time threshold, determine whether the maximum difference is less than a second discharge threshold, wherein the second discharge threshold is less than the first discharge threshold; in response to the maximum difference not being less than the second discharge threshold, continue to adopt the first discharge current allocation method; and in response to the maximum difference being less than the second discharge threshold, adopt a second discharge current allocation method, wherein the second discharge current allocation method is different from the first discharge current allocation method.

[0030] In some embodiments, the allocation unit is configured to adopt a second discharge current allocation method in response to the maximum difference being less than or equal to the first discharge threshold. The second discharge current allocation method includes: distributing the required discharge current evenly according to the number of branch batteries in the multi-branch battery to obtain a pre-average allocation current; and determining the actual discharge current of each branch battery according to the smaller of the pre-average allocation current and the maximum allowable discharge current of the branch battery, wherein the maximum allowable discharge current is determined based on the SOC and temperature state information of each branch battery.

[0031] According to further embodiments of the present disclosure, a current control device is provided, including: a memory; and a processor coupled to the memory, the processor being configured to execute the current control method of any of the above embodiments based on instructions stored in the memory.

[0032] According to further embodiments of the present disclosure, a computer program product is provided, including a computer program that, when executed by a processor, implements the current control method of any of the above embodiments.

[0033] According to further embodiments of the present disclosure, a computer-readable storage medium is provided having a computer program stored thereon that, when executed by a processor, implements the current control method of any of the above embodiments.

[0034] In the above embodiments, during the charging process of the multi-branch battery, a corresponding charging current distribution method is adopted based on whether the SOC deviation of different branch batteries exceeds a first charging threshold, and the charging current is balanced and controlled. This allows the SOC deviation of different branch batteries to be controlled within a reasonable range during charging, reducing the SOC deviation of different branch batteries at the end of charging. This slows down the degradation of the multi-branch battery and delays the decrease in the actual usable capacity of the multi-branch battery. Attached Figure Description

[0035] The accompanying drawings, which form part of this specification, illustrate embodiments of this disclosure and, together with the specification, serve to explain the principles of this disclosure.

[0036] This disclosure will become clearer with reference to the accompanying drawings and the following detailed description, wherein: Figure 1 A flowchart illustrating some embodiments of the current control method of this disclosure is provided. Figure 2 Flowcharts illustrating other embodiments of the current control method of this disclosure are shown; Figure 3 Block diagrams illustrating some embodiments of the current control system of this disclosure are shown; Figure 4Block diagrams illustrating other embodiments of the current control system of this disclosure are shown; Figures 5a to 5d Flowcharts illustrating some embodiments of the current control system of this disclosure are shown; Figure 5e Block diagrams illustrating further embodiments of the current control system of this disclosure are shown; Figure 6 Block diagrams illustrating some embodiments of the current control device of this disclosure; Figure 7 Block diagrams illustrating other embodiments of the current control device of this disclosure; Figure 8 Block diagrams illustrating further embodiments of the current control device of this disclosure; Figure 9 Block diagrams illustrating further embodiments of the current control device of this disclosure are shown. Detailed Implementation

[0037] Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the present disclosure.

[0038] At the same time, it should be understood that, for ease of description, the dimensions of the various parts shown in the accompanying drawings are not drawn according to actual scale.

[0039] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this disclosure or its application or use.

[0040] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0041] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0042] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0043] As described above, the inventors of this disclosure have discovered that during the charging process of a multi-branch battery, there is no equalization control of the SOC of the different branch batteries. This results in a large deviation in the SOC of the different branch batteries at the end of charging.

[0044] To address at least some of the aforementioned problems, this disclosure proposes a current control technology. By balancing the State of Charge (SOC) of different branches of the battery during the charging process, the SOC deviation of different branches at the end of charging is reduced, thereby slowing down the degradation of the multi-branch battery and delaying the decrease in the actual usable capacity of the multi-branch battery.

[0045] Furthermore, in related technologies, during the discharge process of a multi-branch battery, the deviation in State of Charge (SOC) between different branch batteries is reduced by adjusting the output power reference value. However, in a multi-branch battery system, the voltages of different branch batteries are inconsistent, so adjusting the output power reference value will also lead to inconsistent currents in different branch batteries. Since the SOC of a branch battery is obtained by integrating the current over time, the inconsistency in currents between different branch batteries increases the SOC deviation.

[0046] To address at least some of the aforementioned problems, this disclosure proposes a current control technology solution. By adjusting the charging and discharging currents of different branch batteries, the SOC of different branch batteries is balanced and controlled, thereby reducing the SOC deviation of different branch batteries during charging and discharging, slowing down the degradation of multiple branch batteries, and delaying the decrease in the actual usable capacity of multiple branch batteries.

[0047] The following is combined with Figure 1 This example illustrates a current control method applied to a BMS.

[0048] Figure 1 Flowcharts illustrating some embodiments of the current control method of this disclosure are shown.

[0049] like Figure 1 As shown, in step 110, during the charging process of the multi-branch battery, the BMS calculates the maximum difference between the SOCs of different branch batteries based on the SOC corresponding to each branch battery in the multi-branch battery.

[0050] For example, a multi-branch battery consists of n parallel branch batteries. The BMS adopts a three-level architecture, including a main battery management system (MBMU), n sub-battery management systems (SBMU) that control different branch batteries, and acquisition boards distributed in each branch battery.

[0051] For example, in a three-tier BMS architecture, n SBMUs can send the State of Charge (SOC) of the branch batteries they control to the MBMU via the Controller Area Network (CAN) bus. The MBMU then calculates the maximum difference in SOC between different branch batteries based on the SOCs sent by the n SBMUs.

[0052] In step 120, the BMS allocates the charging current according to the comparison result between the maximum difference and the first charging threshold, and adopts the charging current allocation method corresponding to the comparison result to determine the allocation current of each branch battery.

[0053] For example, in a BMS employing a three-level architecture, the MBMU can compare the maximum difference with a first charging threshold. The MBMU can then allocate the charging current according to the comparison result.

[0054] When multiple battery branches serve as the vehicle's power battery, the first charging threshold can be determined based on the vehicle's charging time requirements and the vehicle's requirements for the SOC deviation of different branches.

[0055] In step 130, the BMS determines the requested charging current for each branch battery based on the actual charging current and the allocated current of each branch battery.

[0056] For example, in a three-tier BMS architecture, the MBMU can send the allocated current value for each branch battery to the SBMU responsible for that branch battery. Each SBMU then determines the requested charging current based on the allocated current and the actual charging current of the branch battery.

[0057] In step 140, the BMS instructs the voltage conversion unit of each branch battery to adjust the actual charging current according to the requested charging current.

[0058] For example, the voltage conversion unit may include a DC-DC converter (DCDC). In a BMS with a three-level architecture, the SBMU can interact with the DCDC to instruct the DCDC of each branch battery to adjust the actual charging current according to the requested charging current.

[0059] In the above embodiments, during the charging process of the multi-branch battery, a corresponding charging current allocation method is adopted based on whether the SOC deviation of different branch batteries exceeds a first charging threshold. By balancing the charging current, the SOC deviation of different branch batteries can be controlled within a reasonable range during the charging process, reducing the SOC deviation of different branch batteries at the end of charging. This can slow down the degradation of the multi-branch battery and delay the decrease in the actual usable capacity of the multi-branch battery.

[0060] The following examples illustrate how the charging current is determined in step 120.

[0061] For example, the SBMU or MBMU looks up the maximum allowable charging current for each branch battery based on its SOC and temperature status information. The MBMU sums the maximum allowable charging currents of different branch batteries to obtain the theoretical maximum charging current. The MBMU then uses the smaller of the theoretical maximum charging current and the maximum charging current of the charging station as the actual charging current.

[0062] This maximizes charging capacity while protecting the internal structure of each branch battery. In subsequent steps, the charging current determined in step 120 is balanced and controlled to reduce the SOC deviation between different branch batteries while minimizing charging time. This slows down the degradation of multiple branch batteries and delays the decrease in their actual usable capacity.

[0063] When a branch battery has multiple temperature state information, the maximum allowable charging current can be obtained, for example, by looking up a table based on the branch battery's SOC and the highest temperature among the multiple temperature state information to obtain a first result; by looking up a table based on the first branch battery's SOC and the highest temperature among the multiple temperature state information to obtain a second result; and by taking the smaller value between the first result and the second result as the maximum allowable charging current.

[0064] The following examples illustrate, through exemplary embodiments, the charging current allocation method adopted by the BMS in step 120 when the maximum difference is greater than the first charging threshold.

[0065] In some embodiments, in response to the maximum difference being greater than a first charging threshold, a first charging current allocation method is adopted, the first charging current allocation method comprising: determining the branch battery in each branch battery whose SOC difference from the maximum SOC is greater than the first charging threshold as the first branch battery, the maximum SOC being the maximum value of the SOC of each branch battery; determining a first allocation current for the first branch battery based on the charging current and the maximum allowable charging current of the first branch battery, the maximum allowable charging current being determined based on the SOC and temperature state information of the first branch battery.

[0066] For example, first determine the first distribution current of the first branch battery with the largest SOC deviation, and then determine the first distribution current of the first branch battery with the second largest SOC deviation. The first distribution current shall not exceed the maximum allowable charging current of the first branch battery.

[0067] In some embodiments, the charging current is evenly distributed according to the number of batteries in the first branch to obtain a first pre-average distribution current for the first branch batteries; the smaller value between the first pre-average distribution current and the maximum allowable charging current of the first branch batteries is determined as the first distribution current of the first branch batteries.

[0068] For example, if the first pre-average distribution current does not exceed the maximum allowable charging current of a first branch battery, then the first pre-average distribution current is determined as the first distribution current. If the first pre-average distribution current exceeds the maximum allowable charging current of another first branch battery, then the maximum allowable charging current is determined as the first distribution current.

[0069] In this way, during the charging process of a multi-branch battery, if the SOC deviation between different branches exceeds the first charging threshold, the charging current is preferentially allocated to the first branch with the lower SOC. This can control the SOC deviation between different branches within a reasonable range during charging. It can reduce the SOC deviation between different branches at the end of charging, slow down the degradation of the multi-branch battery, and delay the decrease in the actual usable capacity of the multi-branch battery.

[0070] In some embodiments, the first charging current allocation method includes: in response to the first allocation current being less than the charging current, determining the remaining charging current based on the charging current and the first allocation current; and for the second branch battery other than the first branch battery in the multi-branch battery, distributing the remaining charging current equally according to the number of the second branch batteries to obtain the second allocation current of the second branch battery.

[0071] In this way, by rationally allocating the charging current, it is possible to control the SOC deviation of different branches of the battery within a reasonable range during the charging process, while also shortening the charging time of multiple branches. This reduces the SOC deviation of different branches of the battery at the end of charging, thus slowing down the degradation of the multi-branch battery and delaying the decrease in the actual usable capacity of the multi-branch battery.

[0072] The following examples illustrate the control process adopted by the BMS after the time for allocating according to the first charging current allocation method exceeds the charging time threshold.

[0073] In some embodiments, in response to the time for which the current is allocated according to the first charging current allocation method exceeds a charging time threshold, it is determined whether the maximum difference is less than a second charging threshold, and the second charging threshold is less than the first charging threshold; in response to the maximum difference not being less than the second charging threshold, the first charging current allocation method is continued; in response to the maximum difference being less than the second charging threshold, a second charging current allocation method is adopted, and the second charging current allocation method is different from the first charging current allocation method.

[0074] For example, when multiple battery branches serve as the vehicle's power battery, the second charging threshold can be determined based on the vehicle's charging time requirements and the vehicle's requirements for the SOC deviation of different branches.

[0075] In this way, by adopting the first charging current distribution method, the SOC deviation of different branch batteries can be controlled within a reasonable range (such as the second charging threshold), thereby reducing the SOC deviation of different branch batteries at the end of charging.

[0076] Furthermore, when the SOC deviation of different branch batteries is less than the second charging threshold, the BMS no longer uses the first charging current allocation method. This reduces the SOC deviation of different branch batteries at the end of charging while minimizing BMS processing overhead. It also slows down the degradation of multiple branch batteries and delays the decrease in their actual usable capacity.

[0077] The process of the second charging current distribution method is illustrated below through some embodiments.

[0078] In some embodiments, the second charging current allocation method includes: distributing the charging current equally according to the number of branch batteries in the multi-branch battery to obtain a second pre-average allocation current; and determining the allocation current of each branch battery according to the second pre-average allocation current and the maximum allowable charging current of the branch battery, wherein the maximum allowable charging current is determined based on the SOC and temperature state information of each branch battery.

[0079] For example, the smaller of the second pre-average distribution current and the maximum allowable charging current of the branch battery is determined as the distribution current of the branch battery.

[0080] In this way, by adopting a second charging current distribution method, the SOC deviation of different branch batteries can be maintained within a reasonable range (such as a second charging threshold), reducing the SOC deviation of different branch batteries at the end of charging. This can slow down the degradation of multiple branch batteries and delay the decrease in the actual usable capacity of multiple branch batteries.

[0081] The following examples illustrate, through exemplary embodiments, the charging current allocation method adopted by the BMS in step 120 when the maximum difference is less than or equal to the first charging threshold.

[0082] In some embodiments, in response to the maximum difference being less than or equal to a first charging threshold, a second charging current allocation method is adopted, the second charging current allocation method comprising: distributing the charging current equally according to the number of branch batteries in the multi-branch battery to obtain a second pre-average allocation current; and determining the allocation current of each branch battery according to the second pre-average allocation current and the maximum allowable charging current of the branch battery, wherein the maximum allowable charging current is determined according to the SOC and temperature state information of each branch battery.

[0083] For example, the smaller of the second pre-average distribution current and the maximum allowable charging current of the branch battery is determined as the distribution current of the branch battery.

[0084] Thus, during the charging process of multi-branch batteries, as long as the SOC deviation of different branch batteries does not exceed the first charging threshold, a second charging current allocation method with simpler control logic than the first charging current allocation method is adopted. This method can maintain the SOC deviation of different branch batteries within a reasonable range (such as the first charging threshold) during charging while reducing BMS processing overhead. It can reduce the SOC deviation of different branch batteries at the end of charging, slow down the degradation of multi-branch batteries, and delay the decrease in the actual usable capacity of multi-branch batteries.

[0085] The following examples illustrate how the BMS determines the requested charging current for each branch battery in step 130.

[0086] In some embodiments, the difference between the actual charging current and the maximum allowable charging current of the branch battery is used to compensate the distribution current to obtain the requested charging current of each branch battery.

[0087] For example, in a BMS with a three-level architecture, the SBMU of each branch battery uses the difference between the actual charging current and the maximum allowable charging current of the branch battery to compensate for the allocated current and obtain the requested charging current of each branch battery.

[0088] This method first determines the allocation current based on the maximum allowable charging current of the branch battery, and then compensates for the difference between the actual charging current and the maximum allowable charging current to obtain the requested charging current. This approach reduces the SOC deviation of different branches at the end of charging, while simultaneously lowering BMS processing overhead and reducing charging current allocation errors. It also slows down the degradation of multiple branches and delays the decrease in their actual usable capacity.

[0089] The following examples illustrate the operation of the BMS during the discharge process.

[0090] In some embodiments, during the discharge process of a multi-branch battery, the BMS determines the maximum allowable discharge current of each branch battery based on the SOC and temperature state information of each branch battery; the BMS instructs the voltage conversion unit of each branch battery to adjust the actual discharge current of each branch battery based on the SOC and the maximum allowable discharge current.

[0091] For example, the SBMU or MBMU can look up the maximum allowable discharge current and feedback current of each branch battery by referring to a table based on the SOC and temperature status information of each branch battery.

[0092] The voltage conversion unit includes, for example, a DC-DC converter. The SBMU or MBMU indicates the DC-DC converter of each branch battery and adjusts the actual discharge current of each branch battery according to the SOC and the maximum allowable discharge current.

[0093] In this way, during the discharge process of multiple battery branches, the BMS does not need to make decisions regarding the actual discharge current of each branch. On the one hand, this reduces the computational burden on the BMS. On the other hand, it reduces discharge response lag caused by communication delays, reduces errors in the actual discharge current, and improves the accuracy of SOC equalization control. It also reduces the SOC deviation between different branches during discharge. Finally, it slows down the degradation of multiple battery branches and delays the decrease in their actual usable capacity.

[0094] The following is combined with Figure 2 This example illustrates a current control method applied to a voltage conversion unit.

[0095] Figure 2 Flowcharts illustrating some other embodiments of the current control method of this disclosure are shown.

[0096] like Figure 2 As shown, in step 210, during the discharge process of the multi-branch battery, the voltage conversion unit calculates the maximum difference between the SOCs of different branch batteries based on the SOC corresponding to each branch battery in the multi-branch battery.

[0097] For example, the voltage conversion unit includes a DC-DC converter. The DC-DC converter of a branch battery obtains the state of charge (SOC) of that branch battery by interacting with the SBMU, and obtains the SOC of other branch batteries by communicating with their DC-DC converters via CAN. Then, the voltage conversion unit can calculate the maximum difference between the SOCs of different branch batteries.

[0098] In step 220, the voltage conversion unit allocates the required discharge current according to the comparison result between the maximum difference and the first discharge threshold, and adopts the discharge current allocation method corresponding to the comparison result to determine the actual discharge current of each branch battery.

[0099] For example, when multiple battery branches serve as the vehicle's power battery, the first discharge threshold can be determined based on the vehicle's requirements for the SOC deviation of different branches. The required discharge current can be determined based on the vehicle's overall discharge current.

[0100] The following examples illustrate, through exemplary embodiments, the discharge current distribution method adopted by the voltage conversion unit in step 220 when the maximum difference is greater than the first discharge threshold.

[0101] In some embodiments, in response to a maximum difference greater than a first discharge threshold, a first discharge current allocation method is adopted, the first discharge current allocation method including: determining the actual discharge current according to the order of SOC of each branch battery from high to low, based on the required discharge current and the maximum allowable discharge current of each branch battery, wherein the maximum allowable discharge current is determined based on the SOC and temperature state information of each branch battery.

[0102] The voltage conversion unit includes, for example, a DC-DC converter. The DC-DC converter can obtain the maximum allowable discharge current of the branch battery through the BMS.

[0103] For example, a DC-DC converter, while ensuring that the actual discharge current of each branch battery does not exceed the maximum allowable discharge current, prioritizes allocating the required discharge current to the branch battery with the highest SOC. If the maximum allowable discharge current of the branch battery with the highest SOC cannot meet the required discharge current, the actual discharge current is allocated to the branch battery with the second highest SOC.

[0104] In this way, during the discharge process of a multi-branch battery, if the SOC deviation between different branches exceeds the first discharge threshold, the required discharge current is preferentially allocated to the first branch with the highest SOC. This can control the SOC deviation between different branches within a reasonable range during discharge. This reduces the SOC deviation between different branches during discharge, slows down the degradation of the multi-branch battery, and delays the decrease in the actual usable capacity of the multi-branch battery.

[0105] The following examples illustrate the control flow adopted by the voltage conversion unit after the time for allocation according to the first discharge current allocation method exceeds the discharge time threshold.

[0106] In some embodiments, in response to the time for which the current is allocated according to the first discharge current allocation method exceeds a discharge time threshold, it is determined whether the maximum difference is less than a second discharge threshold, and the second discharge threshold is less than the first discharge threshold; in response to the maximum difference not being less than the second discharge threshold, the first discharge current allocation method is continued; in response to the maximum difference being less than the second discharge threshold, a second discharge current allocation method is adopted, and the second discharge current allocation method is different from the first discharge current allocation method.

[0107] For example, when multiple battery branches serve as the vehicle's power battery, the second discharge threshold can be determined based on the vehicle's requirements for the SOC deviation of different branches.

[0108] In this way, by adopting the first discharge current allocation method, the SOC deviation of different branch batteries can be controlled within a reasonable range (such as the second discharge threshold), reducing the SOC deviation of different branch batteries during discharge. Furthermore, when the SOC deviation of different branch batteries is less than the second discharge threshold, the DC-DC converter no longer uses the first discharge current allocation method. This reduces the SOC deviation of different branch batteries during discharge while minimizing DC-DC processing overhead. It also slows down the degradation of multiple branch batteries and delays the decrease in their actual usable capacity.

[0109] The process of the second discharge current distribution method is illustrated below through some embodiments.

[0110] In some embodiments, the second discharge current distribution method includes: distributing the required discharge current equally according to the number of branch batteries in the multi-branch battery to obtain a pre-average distribution current; and determining the actual discharge current of each branch battery according to the smaller of the pre-average distribution current and the maximum allowable discharge current of the branch battery, wherein the maximum allowable discharge current is determined based on the SOC and temperature state information of each branch battery.

[0111] In this way, by adopting a second discharge current distribution method, the SOC deviation of different branch batteries can be maintained within a reasonable range (such as a second discharge threshold), reducing the SOC deviation of different branch batteries during discharge. This can slow down the degradation of multiple branch batteries and delay the decrease in the actual usable capacity of multiple branch batteries.

[0112] The following examples illustrate, through exemplary embodiments, the discharge current distribution method adopted by the voltage conversion unit in step 220 when the maximum difference is less than or equal to the first discharge threshold.

[0113] In some embodiments, in response to a maximum difference being less than or equal to a first discharge threshold, a second discharge current allocation method is adopted, the second discharge current allocation method comprising: distributing the required discharge current equally according to the number of branch batteries in the multi-branch battery to obtain a pre-average allocation current; and determining the actual discharge current of each branch battery according to the smaller of the pre-average allocation current and the maximum allowable discharge current of the branch battery, wherein the maximum allowable discharge current is determined based on the SOC and temperature state information of each branch battery.

[0114] Thus, during the discharge process of multi-branch batteries, if the SOC deviation between different branch batteries does not exceed the first discharge threshold, a second discharge current allocation method with simpler control logic than the first discharge current allocation method is adopted. This method can maintain the SOC deviation between different branch batteries within a reasonable range (such as the first discharge threshold) during discharge while reducing BMS processing overhead. It can reduce the SOC deviation between different branch batteries during discharge, slow down the degradation of multi-branch batteries, and delay the decrease in the actual usable capacity of multi-branch batteries.

[0115] The current control system of this disclosure is illustrated below by way of some embodiments.

[0116] Figure 3 Block diagrams illustrating some embodiments of the current control system of this disclosure are shown.

[0117] like Figure 3 As shown, the current control system 3 of this embodiment includes a BMS 32 and a voltage conversion unit 34. The BMS 32 is used to execute the current control method applied to the BMS in any of the above embodiments. The voltage conversion unit 34 is used to execute the current control method applied to the voltage conversion unit in any of the above embodiments.

[0118] Figure 4 Block diagrams illustrating other embodiments of the current control system of this disclosure are shown.

[0119] like Figure 4 As shown, the current control system 4 of this embodiment can be installed in an electric vehicle. The current control system 4 includes a high-voltage power distribution unit (PDU), a low-voltage box, n parallel branch batteries (numbered from branch battery a41 to branch battery a4n), and n DC-DC converters (numbered from DC-DCb41 to DC-DCb4n) capable of interacting with the n branch batteries respectively.

[0120] The low-voltage box may contain, for example, n SBMUs (numbered from SBMU c41 to SBMU c4n) capable of interacting with n DC-DC converters, an MBMU, and an Electric Vehicle Communication Controller (EVCC). The BMS may include, for example, an MBMU and n SBMUs. The n DC-DC converters may be voltage conversion units or part of voltage conversion units.

[0121] For example, the MBMU can be responsible for overall external communication of multiple battery branches. During the charging process of multiple battery branches, the MBMU can interact with the EVCC to achieve MCS charging through the Megawatt Charging System (MCS) charging socket. Furthermore, the MBMU can interact with n SBMUs to distribute and control the charging current of n battery branches.

[0122] For example, an SBMU can interact with a DC-DC converter to control the charging and discharging currents of n branch batteries.

[0123] During the discharge process of the multi-branch battery, each branch battery discharges to the load via a DC-DC converter. During the charging process of the multi-branch battery, each branch battery charges from the MCS charging socket via a DC-DC converter.

[0124] The following is combined Figure 5a The working process of the current control system 4 is illustrated by way of example.

[0125] Figure 5a Flowcharts illustrating some embodiments of the current control system of this disclosure are shown.

[0126] like Figure 5a As shown, in step 500a, the high voltage of the multi-branch battery is completed.

[0127] In step 510a, the MBMU determines whether the current mode is charging. If it is charging mode, step 520a is executed; if it is not charging mode, step 560a is executed.

[0128] In step 520a, the MBMU determines that the current mode is charging. In step 530a, the BMS sends an enable command and a charging mode instruction to the DC-DC converter. In step 540a, after receiving the enable command and the charging mode instruction, the DC-DC converter enters constant current mode. In step 550a, the DC-DC converter performs constant current mode current control, and the BMS performs charging mode current control.

[0129] In step 560a, the MBMU determines that the current mode is discharge mode. Then, in step 570a, the BMS sends an enable command and a discharge mode instruction to the DCDC. In step 580a, after receiving the enable command and the discharge mode instruction, the DCDC enters constant voltage mode. In step 590a, the DCDC performs constant voltage mode current control, and the BMS performs discharge mode current control.

[0130] The following is combined Figure 5b This example illustrates the workflow of the BMS in the current control system 4 after performing charging mode current control.

[0131] Figure 5bFlowcharts illustrating some embodiments of the current control system of this disclosure are shown.

[0132] like Figure 5b As shown, in step 510b, the BMS performs charging mode current control. In step 520b, the SBMU determines the maximum allowable charging current of each branch battery based on its SOC and temperature status information, and sends this information to the MBMU.

[0133] In step 530b, the MBMU calculates the theoretical maximum charging current based on the maximum allowable charging current of each branch battery.

[0134] In step 540b, the MBMU uses the smaller of the theoretical maximum charging current and the maximum charging current of the charging station as the charging current.

[0135] In step 550b, the BMS determines whether the maximum difference in SOC between batteries in different branches is greater than a first charging threshold. If the maximum difference is greater than the first charging threshold, step 560b is executed; if the maximum difference is less than or equal to the first charging threshold, step 580b is executed.

[0136] In step 560b, the first charging current distribution method is adopted.

[0137] In response to the fact that the time for allocating according to the first charging current allocation method exceeds the charging time threshold, in step 570b, it is determined whether the maximum difference is less than the second charging threshold. If the maximum difference is less than the second charging threshold, step 580b is executed; if the maximum difference is not less than the second charging threshold, step 560b is executed.

[0138] In step 580b, the BMS adopts a second charging current allocation method that is different from the first charging current allocation method.

[0139] The first charging current allocation method and the second charging current allocation method can be found in the description of the current control method applied to BMS, and will not be repeated here.

[0140] The following is combined Figure 5c This example illustrates the workflow of the DC-DC converter in the current control system 4 after performing constant current mode current control.

[0141] Figure 5c Flowcharts illustrating some embodiments of the current control system of this disclosure are shown.

[0142] like Figure 5c As shown, in step 510c, the DC-DC converter performs constant current mode current control.

[0143] In step 520c, the DC-DC converter is controlled according to the charging current request sent by the BMS.

[0144] In step 530c, the DC-DC converter determines whether the charging pile output voltage is greater than or equal to the overvoltage threshold and whether it is less than or equal to the undervoltage threshold. If the charging pile output voltage is greater than or equal to the overvoltage threshold or less than or equal to the undervoltage threshold, step 540c is executed; if the charging pile output voltage is greater than the undervoltage threshold and less than the overvoltage threshold, step 550c is executed.

[0145] In step 540c, in response to the charging pile output voltage being greater than or equal to the overvoltage threshold, the DC-DC converter stops outputting and reports an overvoltage fault.

[0146] In step 540c, in response to the charging pile output voltage being less than or equal to the undervoltage threshold, the DC-DC converter stops outputting and reports an undervoltage fault.

[0147] In step 550c, the DC-DC converter determines the actual charging current based on the requested charging current and the charging pile output voltage.

[0148] The following example illustrates how, in step 550c, the DC-DC converter determines the actual charging current based on the requested charging current and the charging pile's output voltage.

[0149] For example, undervoltage threshold It can be 1210V, overvoltage threshold. It can be 1250V, the normal output voltage target value of the charging pile. It can be 1230V. (Assuming the current charging station output voltage...) It is 1220V, because The DC-DC converter does not need to report a fault. Assume the requested charging current is... ,because The actual charging current can be calculated using the following formula from DC-DC converters. .

[0150]

[0151] In this way, the DC-DC converter can promptly report faults and stop output during charging, preventing abnormal charging and protecting the internal structure of multiple battery cells. Furthermore, by determining the actual charging current based on the requested charging current and the charging station's output voltage, the DC-DC converter reduces the probability of the output current exceeding the current carrying capacity of the multiple battery cells. This reduces the probability of overcharging multiple battery cells and protects their internal structure.

[0152] The following is combined Figure 5d This example illustrates the workflow of the current control system 4 during the discharge process.

[0153] Figure 5d Flowcharts illustrating some embodiments of the current control system of this disclosure are shown.

[0154] like Figure 5d As shown, in step 510d, the BMS enters the discharge mode current control process.

[0155] In step 520d, the BMS determines the maximum allowable discharge current of each branch battery based on the SOC and temperature status information of each branch battery, and sends it to the DC-DC converter of the branch battery.

[0156] In step 530d, the DC-DC converter performs a constant voltage mode current control process.

[0157] In step 540d, the DC-DC converter calculates the maximum difference in SOC between the batteries in different branches.

[0158] In step 550d, the DC-DC converter determines whether the maximum difference in SOC between the batteries in different branches is greater than a first discharge threshold. If the maximum difference is greater than the first discharge threshold, step 560d is executed; if the maximum difference is less than or equal to the first discharge threshold, step 580d is executed.

[0159] In step 560d, the DC-DC converter adopts the first discharge current distribution method.

[0160] In response to the fact that the time for allocating according to the first discharge current allocation method exceeds the discharge time threshold, in step 570d, the DC-DC converter determines whether the maximum difference is less than the second discharge threshold. If the maximum difference is less than the second discharge threshold, step 580d is executed; if the maximum difference is not less than the second charging threshold, step 560d is executed.

[0161] In step 580d, the DC-DC converter adopts a second discharge current distribution method.

[0162] The first discharge current distribution method and the second discharge current distribution method can be found in the description of the current control method applied to the voltage conversion unit, and will not be repeated here.

[0163] Figure 5e Schematic diagrams of other embodiments of the current control system of this disclosure are shown.

[0164] like Figure 5eAs shown, the current control system 5 of this embodiment can be installed in an electric vehicle. The current control system 5 includes a Battery Thermal Management System (BTMS), a Vehicle Control Unit (VCU), a PDU, a main control low-voltage box, a sub-control low-voltage box, n parallel branch batteries (numbered from branch battery c51 to branch battery c5n), and n DC-DC converters (numbered from DC-DC a51 to DC-DC a5n) and n Battery Disconnect Units (BDUs) (numbered from BDU d51 to BDU d5n) capable of interacting with the n branch batteries respectively.

[0165] The main control low-voltage box includes, for example, an MBMU and an EVCC. The sub-control low-voltage box includes, for example, n SBMUs (numbered from SBMU b51 to SBMU b5n) capable of interacting with n DC-DC converters respectively. The BDU includes, for example, a current-voltage sensor (CVS) (numbered from CVS e51 to CVS e5n).

[0166] Each branch battery may contain, for example, a Battery Pack System (BPS) / Battery Acquisition System (BAS) and m Cell Battery Sample Centers (CSCs). For instance, the CSCs in branch battery c51 are numbered from f511 to f51m, those in branch battery c52 are numbered from f521 to f52m, and those in branch battery c5n are numbered from f5n1 to f5nm.

[0167] The BMS of the current control system 5 may include, for example, an MBMU, an SBMU, and a CSC.

[0168] The workflow of current control system 5 can be found in the description of current control system 4, and will not be repeated here. Additionally, the VCU can determine the maximum allowable charging current for each branch battery and send it to the BMS. The VCU can also determine the maximum allowable discharging current for each branch battery and send it to the DC-DC converter.

[0169] The current control device of this disclosure is illustrated below by way of some embodiments.

[0170] Figure 6 Block diagrams illustrating some embodiments of the current control device of this disclosure are shown.

[0171] like Figure 6 As shown, the current control device of this embodiment, configured in the BMS, includes: a calculation unit 62, which calculates the maximum difference between the SOCs of different branches of the battery based on the SOC corresponding to each branch of the battery during the charging process of the multi-branch battery; an allocation unit 64, configured to allocate the charging current according to the comparison result of the maximum difference and a first discharge threshold, and adopt a charging current allocation method corresponding to the comparison result to determine the allocation current of each branch battery; a determination unit 66, configured to determine the requested charging current of each branch battery based on the actual charging current and the allocation current of each branch battery; and an indication unit 68, configured to instruct the voltage conversion unit of each branch battery to adjust the actual charging current according to the requested charging current.

[0172] In some embodiments, the allocation unit 64 is configured to adopt a first charging current allocation method in response to a maximum difference greater than a first charging threshold. The first charging current allocation method includes: identifying the branch battery in each branch battery whose SOC difference from the maximum SOC is greater than the first charging threshold as the first branch battery, where the maximum SOC is the maximum value of the SOC of each branch battery; determining a first allocation current for the first branch battery based on the charging current and the maximum allowable charging current of the first branch battery, where the maximum allowable charging current is determined based on the SOC and temperature state information of the first branch battery.

[0173] In some embodiments, the allocation unit 64 is configured to distribute the charging current equally according to the number of first branch batteries to obtain a first pre-average allocation current for the first branch batteries; and to determine the smaller value between the first pre-average allocation current and the maximum allowable charging current of the first branch batteries as the first allocation current for the first branch batteries.

[0174] In some embodiments, the allocation unit 64 is configured to, in response to a first allocation current being less than a charging current, determine a remaining charging current based on the charging current and the first allocation current; and to, for a second branch battery other than the first branch battery in a multi-branch battery system, to evenly distribute the remaining charging current based on the number of second branch batteries to obtain a second allocation current for the second branch battery.

[0175] In some embodiments, the allocation unit 64 is configured to, in response to the time for allocation according to the first charging current allocation method exceeding a charging time threshold, determine whether the maximum difference is less than a second charging threshold, wherein the second charging threshold is less than the first charging threshold; in response to the maximum difference not being less than the second charging threshold, continue to adopt the first charging current allocation method; and in response to the maximum difference being less than the second charging threshold, adopt the second charging current allocation method, wherein the second charging current allocation method is different from the first charging current allocation method.

[0176] In some embodiments, the allocation unit 64 is configured to adopt a second charging current allocation method in response to a maximum difference being less than or equal to a first charging threshold. The second charging current allocation method includes: distributing the charging current evenly according to the number of branch batteries in the multi-branch battery to obtain a second pre-average allocation current; and determining the allocation current of each branch battery according to the second pre-average allocation current and the maximum allowable charging current of the branch battery, wherein the maximum allowable charging current is determined based on the SOC and temperature state information of each branch battery.

[0177] In some embodiments, the determining unit 66 is configured to compensate the distribution current using the difference between the actual charging current and the maximum allowable charging current of the branch battery to obtain the requested charging current for each branch battery.

[0178] In some embodiments, the determining unit 66 is configured to determine the maximum allowable discharge current of each branch battery based on the SOC and temperature state information of each branch battery during the discharge process of the multi-branch battery; the indicating unit 68 is configured to instruct the voltage conversion unit of each branch battery to adjust the actual discharge current of each branch battery based on the SOC and the maximum allowable discharge current.

[0179] Figure 7 Block diagrams illustrating other embodiments of the current control device of this disclosure are shown.

[0180] like Figure 7 As shown, the current control device of this embodiment is configured in the voltage conversion unit and includes: a calculation unit 72, configured to calculate the maximum difference between the SOCs of different branches of the battery according to the SOC of each branch of the battery during the discharge process of the multi-branch battery; and an allocation unit 74, configured to allocate the required discharge current according to the comparison result of the maximum difference and the first discharge threshold, and adopt the discharge current allocation method corresponding to the comparison result to determine the actual discharge current of each branch of the battery.

[0181] In some embodiments, the allocation unit 74 is configured to adopt a first discharge current allocation method in response to a maximum difference greater than a first discharge threshold. The first discharge current allocation method includes: determining the actual discharge current based on the order of the SOC of each branch battery from high to low, based on the required discharge current and the maximum allowable discharge current of each branch battery. The maximum allowable discharge current is determined based on the SOC and temperature state information of each branch battery.

[0182] In some embodiments, the allocation unit 74 is configured to, in response to the time for allocation according to the first discharge current allocation method exceeding a discharge time threshold, determine whether the maximum difference is less than a second discharge threshold, wherein the second discharge threshold is less than the first discharge threshold; in response to the maximum difference not being less than the second discharge threshold, continue to adopt the first discharge current allocation method; and in response to the maximum difference being less than the second discharge threshold, adopt the second discharge current allocation method, wherein the second discharge current allocation method is different from the first discharge current allocation method.

[0183] In some embodiments, the allocation unit 74 is configured to adopt a second discharge current allocation method in response to a maximum difference being less than or equal to a first discharge threshold. The second discharge current allocation method includes: distributing the required discharge current evenly according to the number of branch batteries in the multi-branch battery to obtain a pre-average allocation current; and determining the actual discharge current of each branch battery according to the smaller of the pre-average allocation current and the maximum allowable discharge current of the branch battery, wherein the maximum allowable discharge current is determined based on the SOC and temperature state information of each branch battery.

[0184] Figure 8 Block diagrams showing further embodiments of the current control device of this disclosure are presented.

[0185] like Figure 8 As shown, the current control device 8 of this embodiment includes a memory 82 and a processor 84 coupled to the memory 82. The processor 84 is configured to execute the current control method of any embodiment of this disclosure based on instructions stored in the memory 82.

[0186] The memory 82 may include, for example, system memory, fixed non-volatile storage media, etc. The system memory may store, for example, the operating system, application programs, boot loader, database, and other programs.

[0187] The following is combined Figure 9 Further embodiments of the current control device of this disclosure are illustrated by way of example.

[0188] Figure 9 Block diagrams illustrating further embodiments of the current control device of this disclosure are shown.

[0189] like Figure 9 As shown, the current control device 9 of this embodiment includes a memory 910 and a processor 920 coupled to the memory 910. The processor 920 is configured to execute the current control method of any of the foregoing embodiments based on instructions stored in the memory 910.

[0190] The memory 910 may include, for example, system memory, fixed non-volatile storage media, etc. The system memory may store, for example, the operating system, application programs, boot loader, and other programs.

[0191] The current control device 9 may also include an input / output interface 930, a network interface 940, and a storage interface 950. These interfaces 930, 940, and 950, as well as the memory 910 and processor 920, can be connected via, for example, a bus 960. The input / output interface 930 provides a connection interface for input / output devices such as a monitor, mouse, keyboard, touchscreen, microphone, and speakers. The network interface 940 provides a connection interface for various networked devices. The storage interface 950 provides a connection interface for external storage devices such as SD cards and USB flash drives.

[0192] Those skilled in the art will understand that embodiments of this disclosure can be provided as methods, systems, or computer program products. Therefore, this disclosure can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this disclosure can take the form of a computer program product embodied on one or more computer-usable non-transitory storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0193] The current control method, current control system, current control device, computer program product, and computer-readable storage medium according to this disclosure have been described in detail. To avoid obscuring the concept of this disclosure, some details known in the art have not been described. Those skilled in the art will fully understand how to implement the technical solutions disclosed herein based on the above description.

[0194] The methods and systems of this disclosure may be implemented in many ways. For example, they may be implemented by software, hardware, firmware, or any combination of software, hardware, and firmware. The above-described order of steps for the methods is for illustrative purposes only, and the steps of the methods of this disclosure are not limited to the specific order described above unless otherwise specifically stated. Furthermore, in some embodiments, this disclosure may also be implemented as a program recorded on a recording medium, the program including machine-readable instructions for implementing the methods according to this disclosure. Thus, this disclosure also covers recording media storing programs for performing the methods according to this disclosure.

[0195] While specific embodiments of this disclosure have been described in detail by way of examples, those skilled in the art should understand that the examples are for illustrative purposes only and are not intended to limit the scope of this disclosure. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of this disclosure.

Claims

1. A current control method applied to a battery management system (BMS), comprising: During the charging process of the multi-branch battery, the maximum difference between the SOC of different branch batteries is calculated based on the SOC of each branch battery. Based on the comparison result between the maximum difference and the first charging threshold, a charging current allocation method corresponding to the comparison result is adopted to allocate the charging current, so as to determine the allocation current of each branch battery. The requested charging current of each branch battery is determined based on the actual charging current of each branch battery and the allocated current. The voltage conversion unit of each branch battery is instructed to adjust the actual charging current according to the requested charging current.

2. The current control method according to claim 1, wherein, The step of allocating the charging current according to the comparison result between the maximum difference and the first charging threshold, and adopting a charging current allocation method corresponding to the comparison result, to determine the allocated current of each branch battery, includes: In response to the maximum difference being greater than the first charging threshold, a first charging current allocation method is adopted. The first charging current distribution method includes: In each of the branch batteries, the branch battery whose SOC is greater than the difference between the SOC and the maximum SOC is determined as the first branch battery, and the maximum SOC is the maximum value of the SOC of each branch battery. The first distribution current of the first branch battery is determined based on the charging current and the maximum allowable charging current of the first branch battery. The maximum allowable charging current is determined based on the SOC and temperature status information of the first branch battery.

3. The current control method according to claim 2, wherein, Determining the first distribution current of the first branch battery based on the charging current and the maximum allowable charging current of the first branch battery includes: The charging current is evenly distributed according to the number of batteries in the first branch to obtain the first pre-average distribution current of the first branch batteries. The smaller value between the first pre-average distribution current and the maximum allowable charging current of the first branch battery is determined as the first distribution current of the first branch battery.

4. The current control method according to claim 2, wherein, The first charging current distribution method includes: In response to the first allocated current being less than the charging current, the remaining charging current is determined based on the charging current and the first allocated current; For the second branch battery other than the first branch battery in the multi-branch battery, the remaining charging current is evenly distributed according to the number of the second branch batteries to obtain the second distribution current of the second branch battery.

5. The current control method according to claim 2, wherein, The step of allocating the charging current according to the comparison result between the maximum difference and the first charging threshold, and adopting a charging current allocation method corresponding to the comparison result, includes: In response to the fact that the time for allocating according to the first charging current allocation method exceeds the charging time threshold, it is determined whether the maximum difference is less than the second charging threshold, and the second charging threshold is less than the first charging threshold. In response to the maximum difference not being less than the second charging threshold, the first charging current allocation method continues to be adopted; In response to the maximum difference being less than the second charging threshold, a second charging current allocation method is adopted, which is different from the first charging current allocation method.

6. The current control method according to any one of claims 1-5, wherein, The step of allocating the charging current according to the comparison result between the maximum difference and the first charging threshold, and adopting a charging current allocation method corresponding to the comparison result, includes: In response to the maximum difference being less than or equal to the first charging threshold, a second charging current allocation method is adopted. The second charging current distribution method includes: Based on the number of branch batteries in the multi-branch battery, the charging current is evenly distributed to obtain a second pre-average distribution current. The allocation current of each branch battery is determined based on the second pre-average allocation current and the maximum allowable charging current of the branch battery. The maximum allowable charging current is determined based on the SOC and temperature status information of each branch battery.

7. The current control method according to any one of claims 1-5, wherein, The step of determining the requested charging current of each branch battery based on the actual charging current of each branch battery and the allocated current includes: The difference between the actual charging current and the maximum allowable charging current of the branch battery is used to compensate the allocated current, thereby obtaining the requested charging current of each branch battery.

8. The current control method according to any one of claims 1-5, further comprising: During the discharge process of the multi-branch battery, the maximum allowable discharge current of each branch battery is determined based on the SOC and temperature state information of each branch battery. The voltage conversion unit of each branch battery is instructed to adjust the actual discharge current of each branch battery according to the SOC and the maximum allowable discharge current.

9. A current control method applied to a voltage conversion unit, comprising: During the discharge process of the multi-branch battery, the maximum difference between the SOCs of different branch batteries is calculated based on the SOC of each branch battery in the multi-branch battery. Based on the comparison result between the maximum difference and the first discharge threshold, a discharge current allocation method corresponding to the comparison result is adopted to allocate the required discharge current, so as to determine the actual discharge current of each branch battery.

10. The current control method according to claim 9, wherein, The step of allocating the required discharge current based on the comparison result between the maximum difference and the first discharge threshold, and adopting a discharge current allocation method corresponding to the comparison result, includes: In response to the maximum difference being greater than the first discharge threshold, a first discharge current allocation method is adopted. The first discharge current distribution method includes: Based on the SOC of each branch battery in descending order, and according to the required discharge current and the maximum allowable discharge current of each branch battery, the actual discharge current is determined. The maximum allowable discharge current is determined based on the SOC and temperature status information of each branch battery.

11. The current control method according to claim 10, wherein, The step of allocating the required discharge current based on the comparison result between the maximum difference and the first discharge threshold, and adopting a discharge current allocation method corresponding to the comparison result, includes: In response to the fact that the time for allocating according to the first discharge current allocation method exceeds the discharge time threshold, it is determined whether the maximum difference is less than the second discharge threshold, and the second discharge threshold is less than the first discharge threshold. In response to the maximum difference not being less than the second discharge threshold, the first discharge current distribution method continues to be adopted; In response to the maximum difference being less than the second discharge threshold, a second discharge current allocation method is adopted, which is different from the first discharge current allocation method.

12. The current control method according to any one of claims 9-11, wherein, The step of allocating the required discharge current based on the comparison result between the maximum difference and the first discharge threshold, and adopting a discharge current allocation method corresponding to the comparison result, includes: In response to the maximum difference being less than or equal to the first discharge threshold, a second discharge current allocation method is adopted. The second discharge current distribution method includes: Based on the number of branch batteries in the multi-branch battery, the required discharge current is evenly distributed to obtain the pre-average distribution current. The actual discharge current of each branch battery is determined based on the smaller of the pre-average distribution current and the maximum allowable discharge current of the branch battery, wherein the maximum allowable discharge current is determined based on the SOC and temperature state information of each branch battery.

13. A current control system, comprising: A battery management system (BMS) for executing the current control method according to any one of claims 1-8; A voltage conversion unit for performing the current control method according to any one of claims 9-12.

14. A current control device, configured in a battery management system (BMS), comprising: The calculation unit calculates the maximum difference between the SOCs of different branches of the battery during the charging process of the multi-branch battery, based on the SOC of each branch of the battery. The allocation unit is configured to allocate the charging current according to the comparison result between the maximum difference and the first charging threshold, and to adopt the charging current allocation method corresponding to the comparison result, so as to determine the allocation current of each branch battery. The determining unit is configured to determine the requested charging current of each branch battery based on the actual charging current of each branch battery and the allocated current. The indicator unit is configured to instruct the voltage conversion unit of each branch battery to adjust the actual charging current according to the requested charging current.

15. A current control device, disposed in a voltage conversion unit, comprising: The calculation unit is configured to calculate the maximum difference between the SOCs of different branches of the battery during the discharge process of the multi-branch battery, based on the SOC of each branch of the battery. The allocation unit is configured to allocate the required discharge current according to the comparison result between the maximum difference and the first discharge threshold, and to determine the actual discharge current of each branch battery by adopting a discharge current allocation method corresponding to the comparison result.

16. A current control device, comprising: Memory; and A processor coupled to the memory, the processor being configured to execute the current control method of any one of claims 1-8 or the current control method of any one of claims 9-12 based on instructions stored in the memory.

17. A computer program product comprising a computer program that, when executed by a processor, implements the current control method according to any one of claims 1-8 or the current control method according to any one of claims 9-12.

18. A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the current control method according to any one of claims 1-8 or the current control method according to any one of claims 9-12.

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