Multi-branch parallel battery pack discharge working condition circulation control method, device and equipment and storage medium

Abstract

The invention discloses a multi-branch parallel battery pack discharge working condition circulation control method, device and equipment and a storage medium, and relates to the technical field of battery management, and the multi-branch parallel battery pack discharge working condition circulation control method comprises the following steps: detecting the state of charge of a multi-branch parallel battery pack, when the percentage of the residual electric quantity in the total capacity is smaller than a preset percentage, detecting the duration of the discharge working condition; when the duration of the discharge working condition is greater than a preset duration, determining a discharge current limit according to a discharge current difference value between branches, a maximum allowable discharge current, the lowest monomer voltage of the branch with the maximum discharge current, the current discharge power and the number of the branches; and when the duration of the discharge working condition is not greater than the preset duration, determining the discharge current limit according to the discharge current difference between the branches, the maximum allowable discharge current and the minimum monomer voltage of the branch with the maximum discharge current. The circulating current influence caused by the end of the discharge working condition can be reduced.

Description

Technical Field

[0001] The present application relates to the field of battery management technology, and in particular to a method, device, equipment and storage medium for controlling circulating current under discharge conditions of a multi-branch parallel battery pack. Background Art

[0002] As electric vehicles have higher demands for battery life, battery pack capacity continues to increase, and multi-pack solutions are increasingly becoming one of the technical options. Among them, the multi-pack parallel solution is the first choice for the automotive industry because it is compatible with other electrical appliances in the vehicle and does not require major adjustments to the vehicle. Affected by the process, there are differences in the internal resistance of the battery pack branches. After the high current discharge is completed, a large voltage difference is easily generated between different branches, which in turn generates a large circulation current between the branches. In severe cases, it will cause over-discharge of the battery cells, causing irreversible damage.

[0003] At present, the voltage difference between different branches after the discharge is reduced by querying a table composed of real-time battery status parameters to adjust the allowable discharge current. However, for multi-branch battery packs, once the high-current discharge condition suddenly ends at a low charge state, this solution will easily cause a voltage difference between branches, thereby causing a large circulating current. Therefore, how to reduce the impact of the circulating current caused by the end of the discharge condition is a problem that still needs to be solved.

[0004] The above contents are only used to assist in understanding the technical solution of the present application and do not constitute an admission that the above contents are prior art. Summary of the invention

[0005] The main purpose of the present application is to provide a method, device, equipment and storage medium for controlling circulating current in a discharge condition of a multi-branch parallel battery pack, aiming to solve the technical problem of how to reduce the impact of circulating current caused by the end of the discharge condition.

[0006] To achieve the above objectives, the present application proposes a method for controlling circulating current in a discharge condition of a multi-branch parallel battery pack, the method comprising:

[0007] Detect the state of charge of the multi-branch parallel battery pack, and when the percentage of the remaining power to the total capacity is less than the preset percentage, detect the duration of the discharge condition;

[0008] When the discharge condition lasts longer than a preset time, the discharge current limit is determined according to the discharge current difference between branches, the maximum allowable discharge current, the lowest single cell voltage of the branch with the maximum discharge current, the current discharge power, and the number of branches;

[0009] When the duration of the discharge condition is not greater than a preset duration, the discharge current limit is determined according to the discharge current difference between the branches, the maximum allowable discharge current, and the lowest single cell voltage of the branch with the maximum discharge current.

[0010] In one embodiment, the step of determining the discharge current limit according to the discharge current difference between branches, the maximum allowable discharge current, the lowest single cell voltage of the branch with the maximum discharge current, the current discharge power and the number of branches includes:

[0011] Obtain the maximum allowable discharge current, the lowest single cell voltage of the branch with the maximum discharge current, the current discharge power, and the number of branches;

[0012] Detecting a maximum discharge current and a minimum discharge current between branches, and obtaining a discharge current difference between branches according to the maximum discharge current and the minimum discharge current;

[0013] Determine a single current reduction amount according to the product of the number of branches and a preset current value;

[0014] When the lowest single cell voltage is greater than a first preset voltage and the current discharge power is greater than a preset power, the maximum discharge current is reduced according to the single current reduction amount until the discharge current difference between the branches meets the preset requirement, and the reduced maximum discharge current is determined as the discharge current limit.

[0015] In one embodiment, when the lowest cell voltage is greater than a first preset voltage and the current discharge power is greater than a preset power, the maximum discharge current is reduced according to the single current reduction amount until the discharge current difference between the branches meets a preset requirement, and the step of using the reduced maximum discharge current as the discharge current limit includes:

[0016] Subtract the single current reduction amount from the maximum discharge current to obtain a pending discharge current limit;

[0017] When the lowest single cell voltage is greater than a first preset voltage and the current discharge power is greater than a preset power, the discharge current difference between the branches and the discharge duration are periodically detected. When it is detected that the discharge current difference between the branches is greater than the preset current difference and the discharge duration is greater than the preset duration, the undetermined discharge current limit is again reduced by the current single reduction amount.

[0018] When it is detected that the discharge current difference between the branches is not greater than the preset current difference or the discharge duration is not greater than the preset duration, the pending discharge current limit is determined as the discharge current limit.

[0019] In one embodiment, after the step of subtracting the single current reduction amount from the maximum discharge current to obtain the pending discharge current limit, the method further includes:

[0020] Detecting the minimum cell voltage and the current discharge power;

[0021] When the lowest cell voltage is not greater than the first preset voltage or the current discharge power is not greater than the preset power, the discharge current limit is calculated according to the preset power.

[0022] In one embodiment, the step of determining the discharge current limit according to the discharge current difference between branches, the maximum allowable discharge current, and the lowest cell voltage of the branch with the maximum discharge current comprises:

[0023] Obtain the maximum allowable discharge current and the lowest single cell voltage of the branch with the maximum discharge current;

[0024] Detecting a maximum discharge current and a minimum discharge current between branches, and obtaining a discharge current difference between branches according to the maximum discharge current and the minimum discharge current;

[0025] When the lowest cell voltage is not greater than a second preset voltage, reducing the maximum discharge current according to the discharge current difference to obtain a discharge current limit;

[0026] When the lowest cell voltage is greater than a second preset voltage, the maximum discharge current is determined as a discharge current limit.

[0027] In one embodiment, the step of reducing the maximum discharge current according to the discharge current difference to obtain a discharge current limit comprises:

[0028] Comparing the discharge current difference with a preset current difference, and determining a preset ratio according to the comparison result;

[0029] Multiplying the maximum discharge current by a preset ratio to obtain a to-be-determined discharge current limit;

[0030] Periodically detecting the difference between the lowest cell voltage and the discharge current, and when the lowest cell voltage is not greater than a third preset voltage, determining the preset ratio again according to a comparison result between the discharge current difference and the preset current difference;

[0031] The pending discharge current limit is multiplied by the preset ratio again until the lowest cell voltage is greater than the third preset voltage, and the finally obtained pending discharge current limit is determined as the discharge current limit, wherein the third preset voltage is greater than the second preset voltage.

[0032] In one embodiment, the step of comparing the discharge current difference with a preset current difference and determining a preset ratio according to the comparison result comprises:

[0033] When the discharge current difference is greater than the preset current difference, taking the first preset ratio as the final preset ratio;

[0034] When the discharge current difference is not greater than the preset current difference, a second preset ratio is used as the final preset ratio, wherein the second preset ratio is greater than the first preset ratio.

[0035] In addition, to achieve the above-mentioned purpose, the present application also proposes a multi-branch parallel battery pack discharge condition circulating current control device, the multi-branch parallel battery pack discharge condition circulating current control device comprising:

[0036] A state detection module is used to detect the state of charge of a multi-branch parallel battery pack, and when the percentage of the remaining power to the total capacity is less than a preset percentage, detect the duration of the discharge condition;

[0037] A first determination module is used to determine the discharge current limit according to the discharge current difference between branches, the maximum allowable discharge current, the lowest single cell voltage of the branch with the maximum discharge current, the current discharge power and the number of branches when the discharge condition lasts for a period longer than a preset period;

[0038] The second determination module is used to determine the discharge current limit according to the discharge current difference between branches, the maximum allowable discharge current, and the lowest single cell voltage of the branch with the maximum discharge current when the discharge condition lasts for no longer than a preset time.

[0039] In addition, to achieve the above-mentioned objectives, the present application also proposes a multi-branch parallel battery pack discharge condition circulating current control device, the device comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, the computer program being configured to implement the steps of the multi-branch parallel battery pack discharge condition circulating current control method as described above.

[0040] In addition, to achieve the above-mentioned purpose, the present application also proposes a storage medium, which is a computer-readable storage medium, and a computer program is stored on the storage medium. When the computer program is executed by the processor, the steps of the circulating current control method of the multi-branch parallel battery pack discharge condition as described above are implemented.

[0041] In addition, to achieve the above-mentioned purpose, the present application also provides a computer program product, which includes a computer program, and when the computer program is executed by a processor, it implements the steps of the circulating current control method of the multi-branch parallel battery pack discharge condition as described above.

[0042] The present application provides a method for controlling circulating current under discharge conditions of a multi-branch parallel battery pack. The present application detects the state of charge of the multi-branch parallel battery pack, and when the percentage of remaining power to total capacity is less than a preset percentage, detects the duration of the discharge condition; when the duration of the discharge condition is greater than the preset duration, determines the discharge current limit based on the discharge current difference between branches, the maximum allowable discharge current, the lowest single cell voltage of the branch with the largest discharge current, the current discharge power, and the number of branches; when the duration of the discharge condition is not greater than the preset duration, determines the discharge current limit based on the discharge current difference between branches, the maximum allowable discharge current, and the lowest single cell voltage of the branch with the largest discharge current.

[0043] In summary, the present application solves the technical problem of how to reduce the impact of the circulating current caused by the end of the discharge condition by implementing a circulating current control strategy. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0045] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0046] Figure 1 A flow chart showing a first embodiment of a method for controlling circulating current in a discharge condition of a multi-branch parallel battery pack of the present application;

[0047] Figure 2 A flow chart showing a second embodiment of the method for controlling circulating current under discharge conditions of a multi-branch parallel battery pack of the present application;

[0048] Figure 3 A flow chart showing a third embodiment of the method for controlling circulating current in a discharge condition of a multi-branch parallel battery pack of the present application;

[0049] Figure 4 This is a schematic diagram of the module structure of the circulating current control device for a multi-branch parallel battery pack in a discharge condition according to an embodiment of the present application;

[0050] Figure 5 Schematic diagram of the equipment structure of the hardware operating environment involved in the method for controlling circulating current under discharge conditions of a multi-branch parallel battery pack in an embodiment of the present application.

[0051] The purpose, features and advantages of this application will be further described in conjunction with the embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0052] It should be understood that the specific embodiments described herein are only used to explain the technical solutions of the present application and are not used to limit the present application.

[0053] In order to better understand the technical solution of the present application, a detailed description will be given below in conjunction with the accompanying drawings and specific implementation methods.

[0054] The main solution of the present application is to detect the charge state of a multi-branch parallel battery pack, and when the percentage of remaining power to total capacity is less than a preset percentage, detect the duration of the discharge condition; when the discharge condition lasts longer than the preset duration, determine the discharge current limit based on the discharge current difference between branches, the maximum allowable discharge current, the lowest single cell voltage of the branch with the largest discharge current, the current discharge power, and the number of branches; when the discharge condition lasts no longer than the preset duration, determine the discharge current limit based on the discharge current difference between branches, the maximum allowable discharge current, and the lowest single cell voltage of the branch with the largest discharge current.

[0055] At present, the voltage difference between different branches after the discharge is reduced by querying a table composed of real-time battery status parameters to adjust the allowable discharge current. However, for multi-branch battery packs, once the high-current discharge condition suddenly ends at a low charge state, this solution will easily cause a voltage difference between branches, thereby causing a large circulating current. Therefore, how to reduce the impact of the circulating current caused by the end of the discharge condition is a problem that still needs to be solved.

[0056] The present application reduces the impact of circulating current caused by the end of the discharge condition by implementing a circulating current control strategy.

[0057] Based on this, the embodiment of the present application provides a method for controlling circulating current in a discharge condition of a multi-branch parallel battery pack, referring to Figure 1 , Figure 1 This is a flow chart of the first embodiment of the circulating current control method for a multi-branch parallel battery pack under discharge conditions of the present application.

[0058] In this embodiment, the circulating current control method for a multi-branch parallel battery pack under discharge condition includes steps S10 to S30:

[0059] Step S10: detecting the state of charge of the multi-branch parallel battery pack, and when the percentage of the remaining power to the total capacity is less than a preset percentage, detecting the duration of the discharge condition;

[0060] It should be noted that the execution subject of this embodiment can be a computing service device with data processing, network communication and program running functions, such as a tablet computer, a personal computer, a mobile phone, etc., or an electronic device capable of realizing the above functions, a multi-branch parallel battery pack discharge condition circulating current control device, etc. The following takes the multi-branch parallel battery pack discharge condition circulating current control device as an example to illustrate this embodiment and the following embodiments.

[0061] It should be noted that a multi-branch parallel battery pack refers to connecting multiple battery packs in parallel to form a battery pack with a larger total capacity and capable of providing more current; the state of charge (SOC) is a parameter used to describe the remaining capacity of the battery, usually expressed as a percentage, reflecting the ratio of the current amount of electricity stored in the battery to the amount of electricity stored when the battery is fully charged. When the SOC is lower than the preset ratio, the circulation control strategy is turned on. The preset ratio can be set according to the actual situation. For example, the preset ratio can be set to 10%. When the SOC is lower than 10%, the duration of the discharge condition is detected, and the corresponding circulation control strategy is selected according to the duration.

[0062] Step S20: when the discharge condition lasts longer than a preset time, the discharge current limit is determined according to the discharge current difference between branches, the maximum allowable discharge current, the lowest single cell voltage of the branch with the maximum discharge current, the current discharge power, and the number of branches;

[0063] It is understandable that the preset duration can be determined according to actual conditions. For example, 10 seconds is the preset duration. When the discharge condition lasts longer than 10 seconds, the discharge current limit is determined by the discharge current difference between branches, the maximum allowable discharge current, the minimum single-cell voltage of the branch with the maximum discharge current, the current discharge power and the number of branches.

[0064] Step S30: when the discharge condition lasts for no longer than a preset time, the discharge current limit is determined according to the discharge current difference between branches, the maximum allowable discharge current, and the lowest cell voltage of the branch with the maximum discharge current.

[0065] It is understandable that when the discharge condition lasts for no more than 10 seconds, the discharge current limit is determined by the discharge current difference between branches, the maximum allowable discharge current, and the lowest single cell voltage of the branch with the maximum discharge current.

[0066] The present embodiment detects the state of charge of a multi-branch parallel battery pack, and when the percentage of remaining power to total capacity is less than a preset percentage, detects the duration of the discharge condition; when the duration of the discharge condition is greater than the preset duration, determines the discharge current limit based on the discharge current difference between branches, the maximum allowable discharge current, the lowest cell voltage of the branch with the largest discharge current, the current discharge power, and the number of branches; when the duration of the discharge condition is not greater than the preset duration, determines the discharge current limit based on the discharge current difference between branches, the maximum allowable discharge current, and the lowest cell voltage of the branch with the largest discharge current.

[0067] In summary, this embodiment reduces the impact of the circulating current caused by the end of the discharge condition by implementing the circulating current control strategy.

[0068] Based on the first embodiment of the present application, in the second embodiment of the present application, the same or similar contents as those in the above-mentioned embodiment 1 can be referred to the above introduction, and will not be repeated in the following. Figure 2 , step S20 includes steps S201 to S204:

[0069] Step S201: obtaining the maximum allowable discharge current, the lowest single cell voltage of the branch with the maximum discharge current, the current discharge power and the number of branches;

[0070] It should be noted that the maximum allowable discharge current is obtained by querying a data table composed of the real-time status parameters of the battery (such as voltage, current, temperature, SOC, etc.). The allowable discharge current in the data table is obtained by testing the battery cell without lithium deposition as the boundary condition, and is the maximum limit discharge current allowed by the battery pack.

[0071] Step S202: Detecting a maximum discharge current and a minimum discharge current between branches, and obtaining a discharge current difference between branches according to the maximum discharge current and the minimum discharge current;

[0072] It is understandable that the discharge current difference is the maximum discharge current minus the minimum discharge current.

[0073] Step S203: determining a single current reduction amount according to the product of the number of branches and a preset current value;

[0074] Taking the preset current value of 20A as an example, the single current reduction amount is 20 multiplied by the number of branches.

[0075] Step S204: When the lowest single cell voltage is greater than a first preset voltage and the current discharge power is greater than a preset power, the maximum discharge current is reduced according to the single current reduction amount until the discharge current difference between the branches meets the preset requirement, and the reduced maximum discharge current is determined as the discharge current limit.

[0076] It is understandable that the first preset voltage and the preset power are determined according to actual conditions, for example, the first preset voltage is 2.5V, and the preset power is 15kw.

[0077] In a feasible manner, when the lowest single cell voltage is greater than a first preset voltage and the current discharge power is greater than a preset power, the maximum discharge current is reduced according to the single current reduction amount until the discharge current difference between the branches meets the preset requirement, and the step of using the reduced maximum discharge current as the discharge current limit includes:

[0078] Subtract the single current reduction amount from the maximum discharge current to obtain a pending discharge current limit;

[0079] When the lowest single cell voltage is greater than a first preset voltage and the current discharge power is greater than a preset power, the discharge current difference between the branches and the discharge duration are periodically detected. When it is detected that the discharge current difference between the branches is greater than the preset current difference and the discharge duration is greater than the preset duration, the undetermined discharge current limit is again reduced by the current single reduction amount.

[0080] When it is detected that the discharge current difference between the branches is not greater than the preset current difference or the discharge duration is not greater than the preset duration, the pending discharge current limit is determined as the discharge current limit.

[0081] It is understandable that when the minimum single-cell voltage is greater than 2.5v and the current discharge power is greater than 15kw, when it is detected that the discharge current difference between the branches is greater than 20A and the discharge duration is greater than 10 seconds, the result of subtracting the single reduction amount of the current from the maximum allowable discharge current is used as the pending discharge current limit, and the detection of the discharge current difference and the discharge duration between the branches is a periodic detection. After adjusting the pending discharge current limit, wait for a period of time, and then detect the discharge current difference and the discharge duration again. If the conditions that the discharge current difference is greater than 20A and the discharge duration is greater than 10 seconds are still met, the pending discharge current limit is again subtracted from the single reduction amount of the current until the discharge current difference is not greater than 20A or the discharge duration is not greater than 10 seconds.

[0082] In a feasible manner, after the step of subtracting the single current reduction amount from the maximum discharge current to obtain the to-be-determined discharge current limit, the step further includes:

[0083] Detecting the minimum cell voltage and the current discharge power;

[0084] When the lowest cell voltage is not greater than the first preset voltage or the current discharge power is not greater than the preset power, the discharge current limit is calculated according to the preset power.

[0085] It is understandable that when determining the discharge current limit, the power of the battery pack cannot be too low, and at least needs to be able to support the vehicle's running. Therefore, when it is detected that the lowest single cell voltage is not greater than 2.5V or the current discharge power is not greater than 15kw, the corresponding current value is directly calculated based on 15kw and used as the discharge current limit.

[0086] This embodiment obtains the maximum allowable discharge current, the lowest single cell voltage of the branch with the maximum discharge current, the current discharge power, and the number of branches; detects the maximum discharge current and the minimum discharge current between the branches, and obtains the discharge current difference between the branches according to the maximum discharge current and the minimum discharge current; determines the single current reduction amount according to the product of the number of branches and the preset current value; when the lowest single cell voltage is greater than the first preset voltage and the current discharge power is greater than the preset power, reduces the maximum discharge current according to the single current reduction amount until the discharge current difference between the branches meets the preset requirements, and determines the reduced maximum discharge current as the discharge current limit.

[0087] In summary, this embodiment solves the technical problem of how to reduce the impact of the circulating current caused by the end of the discharge condition when the discharge condition is long by continuously reducing the allowable discharge current limit.

[0088] Based on the first embodiment of the present application, in the second embodiment of the present application, the same or similar contents as those in the above-mentioned embodiment 1 can be referred to the above introduction, and will not be repeated in the following. Figure 3 , step S30 includes steps S301 to S304:

[0089] Step S301: obtaining the maximum allowable discharge current and the lowest cell voltage of the branch with the maximum discharge current;

[0090] It should be noted that the maximum allowable discharge current is obtained by querying a data table composed of the real-time status parameters of the battery (such as voltage, current, temperature, SOC, etc.). The allowable discharge current in the data table is obtained by testing the battery cell without lithium deposition as the boundary condition, and is the maximum limit discharge current allowed by the battery pack.

[0091] Step S302: Detecting a maximum discharge current and a minimum discharge current between branches, and obtaining a discharge current difference between branches according to the maximum discharge current and the minimum discharge current;

[0092] It is understandable that the discharge current difference is the maximum discharge current minus the minimum discharge current.

[0093] Step S303: when the lowest cell voltage is not greater than a second preset voltage, reducing the maximum discharge current according to the discharge current difference to obtain a discharge current limit;

[0094] It is understandable that, taking 2.5V as an example of the second preset voltage, when the lowest cell voltage is not greater than 2.5V, the maximum discharge current is reduced according to the discharge current difference to obtain the discharge current limit.

[0095] In a feasible manner, the step of reducing the maximum discharge current according to the discharge current difference to obtain a discharge current limit includes:

[0096] Comparing the discharge current difference with a preset current difference, and determining a preset ratio according to the comparison result;

[0097] Multiplying the maximum discharge current by a preset ratio to obtain a to-be-determined discharge current limit;

[0098] Periodically detecting the difference between the lowest cell voltage and the discharge current, and when the lowest cell voltage is not greater than a third preset voltage, determining the preset ratio again according to a comparison result between the discharge current difference and the preset current difference;

[0099] The pending discharge current limit is multiplied by the preset ratio again until the lowest cell voltage is greater than the third preset voltage, and the finally obtained pending discharge current limit is determined as the discharge current limit, wherein the third preset voltage is greater than the second preset voltage.

[0100] It is understandable that the third preset voltage is 3V for example, and the third preset voltage is greater than the second preset voltage, and the discharge current limit is obtained by continuously multiplying the pending discharge current limit by the preset ratio until the lowest cell voltage is greater than 3V.

[0101] In a feasible manner, the step of comparing the discharge current difference with a preset current difference and determining a preset ratio according to the comparison result includes:

[0102] When the discharge current difference is greater than the preset current difference, taking the first preset ratio as the final preset ratio;

[0103] When the discharge current difference is not greater than the preset current difference, a second preset ratio is used as the final preset ratio, wherein the second preset ratio is greater than the first preset ratio.

[0104] It is understandable that the preset current difference is 20A as an example, the first preset ratio is 0.5 as an example, and the second preset ratio is 0.75 as an example. When the discharge current difference is greater than 20A, the final preset ratio is 0.5, and when the discharge current difference is not greater than 20A, the final preset ratio is 0.75.

[0105] Step S304: when the lowest cell voltage is greater than a second preset voltage, determining the maximum discharge current as a discharge current limit.

[0106] It is understandable that when the lowest cell voltage is greater than 2.5 V, the maximum allowable discharge current obtained by looking up the data table can be directly used as the discharge current limit.

[0107] This embodiment obtains the maximum allowable discharge current and the lowest single cell voltage of the branch with the maximum discharge current;

[0108] Detect the maximum discharge current and the minimum discharge current between the branches, and obtain the discharge current difference between the branches according to the maximum discharge current and the minimum discharge current; when the lowest single cell voltage is not greater than a second preset voltage, reduce the maximum discharge current according to the discharge current difference to obtain a discharge current limit; when the lowest single cell voltage is greater than the second preset voltage, determine the maximum discharge current as the discharge current limit.

[0109] In summary, this embodiment solves the technical problem of how to reduce the impact of the circulating current caused by the end of the discharge condition when the discharge condition is short by adjusting the allowable discharge current limit.

[0110] The present application also provides a multi-branch parallel battery pack discharge condition circulating current control device, please refer to Figure 4 , the multi-branch parallel battery pack discharge condition circulating current control device comprises:

[0111] The state detection module 10 is used to detect the state of charge of the multi-branch parallel battery pack, and when the percentage of the remaining power to the total capacity is less than a preset percentage, detect the duration of the discharge condition;

[0112] A first determination module 20 is used to determine the discharge current limit according to the discharge current difference between branches, the maximum allowable discharge current, the lowest single cell voltage of the branch with the maximum discharge current, the current discharge power and the number of branches when the discharge condition lasts longer than a preset time;

[0113] The second determination module 30 is used to determine the discharge current limit according to the discharge current difference between branches, the maximum allowable discharge current, and the lowest single cell voltage of the branch with the maximum discharge current when the discharge condition lasts for no longer than a preset time.

[0114] The present embodiment detects the state of charge of a multi-branch parallel battery pack, and when the percentage of remaining power to total capacity is less than a preset percentage, detects the duration of the discharge condition; when the duration of the discharge condition is greater than the preset duration, determines the discharge current limit based on the discharge current difference between branches, the maximum allowable discharge current, the lowest cell voltage of the branch with the largest discharge current, the current discharge power, and the number of branches; when the duration of the discharge condition is not greater than the preset duration, determines the discharge current limit based on the discharge current difference between branches, the maximum allowable discharge current, and the lowest cell voltage of the branch with the largest discharge current.

[0115] In summary, this embodiment reduces the impact of the circulating current caused by the end of the discharge condition by implementing the circulating current control strategy.

[0116] In one embodiment, the first determination module 20 is also used to obtain the maximum allowable discharge current, the minimum single-cell voltage of the branch with the maximum discharge current, the current discharge power and the number of branches; detect the maximum discharge current and the minimum discharge current between the branches, and obtain the discharge current difference between the branches based on the maximum discharge current and the minimum discharge current; determine the single current reduction amount according to the product of the number of branches and the preset current value; when the minimum single-cell voltage is greater than the first preset voltage and the current discharge power is greater than the preset power, reduce the maximum discharge current according to the single current reduction amount until the discharge current difference between the branches meets the preset requirements, and determine the reduced maximum discharge current as the discharge current limit.

[0117] In one embodiment, the first determination module 20 is further used to subtract the single current reduction amount from the maximum discharge current to obtain a pending discharge current limit; when the minimum single cell voltage is greater than the first preset voltage and the current discharge power is greater than the preset power, the discharge current difference between the branches and the discharge duration are periodically detected. When it is detected that the discharge current difference between the branches is greater than the preset current difference and the discharge duration is greater than the preset duration, the pending discharge current limit is again subtracted from the single current reduction amount; when it is detected that the discharge current difference between the branches is not greater than the preset current difference or the discharge duration is not greater than the preset duration, the pending discharge current limit is determined as the discharge current limit.

[0118] In one embodiment, the first determination module 20 is further used to detect the minimum cell voltage and the current discharge power; when the minimum cell voltage is not greater than the first preset voltage or the current discharge power is not greater than the preset power, the discharge current limit is calculated according to the preset power.

[0119] In one embodiment, the second determination module 30 is further used to obtain the maximum allowable discharge current and the minimum cell voltage of the branch with the maximum discharge current; detect the maximum discharge current and the minimum discharge current between the branches, and obtain the discharge current difference between the branches based on the maximum discharge current and the minimum discharge current; when the minimum cell voltage is not greater than the second preset voltage, reduce the maximum discharge current according to the discharge current difference to obtain the discharge current limit; when the minimum cell voltage is greater than the second preset voltage, determine the maximum discharge current as the discharge current limit.

[0120] In one embodiment, the second determination module 30 is further used to compare the discharge current difference with the preset current difference, and determine the preset ratio according to the comparison result; multiply the maximum discharge current by the preset ratio to obtain a pending discharge current limit; periodically detect the minimum cell voltage and the discharge current difference, and when the minimum cell voltage is not greater than the third preset voltage, again determine the preset ratio according to the comparison result between the discharge current difference and the preset current difference; multiply the pending discharge current limit by the preset ratio again until the minimum cell voltage is greater than the third preset voltage, and determine the final pending discharge current limit as the discharge current limit, wherein the third preset voltage is greater than the second preset voltage.

[0121] In one embodiment, the second determination module 30 is further used to use the first preset ratio as the final preset ratio when the discharge current difference is greater than the preset current difference; and use the second preset ratio as the final preset ratio when the discharge current difference is not greater than the preset current difference, wherein the second preset ratio is greater than the first preset ratio.

[0122] The multi-branch parallel battery pack discharge condition circulating current control device provided in the present application adopts the multi-branch parallel battery pack discharge condition circulating current control method in the above embodiment, which can solve the technical problem of how to reduce the impact of the circulating current caused by the end of the discharge condition. Compared with the prior art, the beneficial effects of the multi-branch parallel battery pack discharge condition circulating current control device provided in the present application are the same as the beneficial effects of the multi-branch parallel battery pack discharge condition circulating current control method provided in the above embodiment, and the other technical features of the multi-branch parallel battery pack discharge condition circulating current control device are the same as the features disclosed in the above embodiment method, which will not be repeated here.

[0123] The present application provides a multi-branch parallel battery pack discharge condition circulating current control device, and the multi-branch parallel battery pack discharge condition circulating current control device includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the multi-branch parallel battery pack discharge condition circulating current control method in the above-mentioned embodiment one.

[0124] Reference below Figure 5 , which shows a schematic diagram of the structure of a multi-branch parallel battery pack discharge condition circulation control device suitable for implementing the embodiment of the present application. The multi-branch parallel battery pack discharge condition circulation control device in the embodiment of the present application may include but is not limited to mobile terminals such as mobile phones, laptop computers, digital broadcast receivers, PDAs (Personal Digital Assistants), PADs (Portable Application Descriptions), PMPs (Portable Media Players), vehicle-mounted terminals (such as vehicle-mounted navigation terminals), etc., and fixed terminals such as digital TVs, desktop computers, etc. Figure 5 The multi-branch parallel battery pack discharge condition circulating current control device shown is only an example and should not bring any limitation to the functions and scope of use of the embodiments of the present application.

[0125] like Figure 5As shown, the multi-branch parallel battery pack discharge condition circulation control device may include a processing device 1001 (such as a central processing unit, a graphics processor, etc.), which can perform various appropriate actions and processes according to the program stored in the read-only memory (ROM: Read Only Memory) 1002 or the program loaded from the storage device 1003 to the random access memory (RAM: Random Access Memory) 1004. In RAM1004, various programs and data required for the operation of the multi-branch parallel battery pack discharge condition circulation control device are also stored. The processing device 1001, ROM1002 and RAM1004 are connected to each other through a bus 1005. The input / output (I / O) interface 1006 is also connected to the bus. Typically, the following systems can be connected to the I / O interface 1006: input devices 1007 including, for example, a touch screen, a touchpad, a keyboard, a mouse, an image sensor, a microphone, an accelerometer, a gyroscope, etc.; output devices 1008 including, for example, a liquid crystal display (LCD), a speaker, a vibrator, etc.; storage devices 1003 including, for example, a magnetic tape, a hard disk, etc.; and communication devices 1009. The communication device 1009 can allow the multi-branch parallel battery pack discharge condition circulation control device to communicate wirelessly or wired with other devices to exchange data. Although the figure shows a multi-branch parallel battery pack discharge condition circulation control device with various systems, it should be understood that it is not required to implement or have all the systems shown. More or fewer systems may be implemented or have instead.

[0126] In particular, according to the embodiments disclosed in the present application, the process described above with reference to the flowchart can be implemented as a computer software program. For example, the embodiments disclosed in the present application include a computer program product, which includes a computer program carried on a computer-readable medium, and the computer program includes a program code for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from a network through a communication device, or installed from a storage device 1003, or installed from a ROM 1002. When the computer program is executed by the processing device 1001, the above-mentioned functions defined in the method of the embodiment disclosed in the present application are executed.

[0127] The multi-branch parallel battery pack discharge condition circulating current control device provided by the present application adopts the multi-branch parallel battery pack discharge condition circulating current control method in the above embodiment, which can solve the technical problem of how to reduce the impact of the circulating current caused by the end of the discharge condition. Compared with the prior art, the beneficial effects of the multi-branch parallel battery pack discharge condition circulating current control device provided by the present application are the same as the beneficial effects of the multi-branch parallel battery pack discharge condition circulating current control method provided by the above embodiment, and the other technical features of the multi-branch parallel battery pack discharge condition circulating current control device are the same as the features disclosed in the previous embodiment method, which will not be repeated here.

[0128] It should be understood that the various parts disclosed in this application can be implemented by hardware, software, firmware or a combination thereof. In the description of the above embodiments, specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0129] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

[0130] The present application provides a computer-readable storage medium having computer-readable program instructions (i.e., a computer program) stored thereon, and the computer-readable program instructions are used to execute the circulating current control method for a multi-branch parallel battery pack in a discharge condition in the above-mentioned embodiment.

[0131] The computer-readable storage medium provided in the present application may be, for example, a USB flash drive, but is not limited to electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, systems or devices, or any combination of the above. More specific examples of computer-readable storage media may include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In this embodiment, the computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in combination with an instruction execution system, system or device. The program code contained on the computer-readable storage medium may be transmitted using any appropriate medium, including but not limited to: wires, optical cables, RF (Radio Frequency), etc., or any suitable combination of the above.

[0132] The above-mentioned computer-readable storage medium may be included in the circulating current control device for the discharge condition of a multi-branch parallel battery pack; or it may exist independently without being assembled into the circulating current control device for the discharge condition of a multi-branch parallel battery pack.

[0133] The above-mentioned computer-readable storage medium carries one or more programs. When the above-mentioned one or more programs are executed by the multi-branch parallel battery pack discharge condition circulation control device, the multi-branch parallel battery pack discharge condition circulation control device: detects the charge state of the multi-branch parallel battery pack, and when the percentage of the remaining power to the total capacity is less than the preset percentage, detects the duration of the discharge condition; when the duration of the discharge condition is greater than the preset duration, determines the discharge current limit according to the discharge current difference between branches, the maximum allowable discharge current, the lowest single cell voltage of the branch with the largest discharge current, the current discharge power and the number of branches; when the duration of the discharge condition is not greater than the preset duration, determines the discharge current limit according to the discharge current difference between branches, the maximum allowable discharge current, and the lowest single cell voltage of the branch with the largest discharge current.

[0134] Computer program code for performing the operations of the present application may be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, C++, and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may be executed entirely on the user's computer, partially on the user's computer, as a separate software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0135] The flow chart and block diagram in the accompanying drawings illustrate the possible architecture, function and operation of the system, method and computer program product according to various embodiments of the present application. In this regard, each square box in the flow chart or block diagram can represent a module, a program segment or a part of a code, and the module, the program segment or a part of the code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the square box can also occur in a sequence different from that marked in the accompanying drawings. For example, two square boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each square box in the block diagram and / or flow chart, and the combination of the square boxes in the block diagram and / or flow chart can be implemented with a dedicated hardware-based system that performs a specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0136] The modules involved in the embodiments described in this application may be implemented by software or hardware, wherein the name of the module does not constitute a limitation on the unit itself in some cases.

[0137] The readable storage medium provided in the present application is a computer-readable storage medium, which stores computer-readable program instructions (i.e., computer programs) for executing the above-mentioned circulating current control method for the discharge condition of a multi-branch parallel battery pack, and can solve the technical problem of how to reduce the impact of the circulating current caused by the end of the discharge condition. Compared with the prior art, the beneficial effects of the computer-readable storage medium provided in the present application are the same as the beneficial effects of the circulating current control method for the discharge condition of a multi-branch parallel battery pack provided in the above-mentioned embodiment, and will not be repeated here.

[0138] The present application also provides a computer program product, including a computer program, which, when executed by a processor, implements the steps of the above-mentioned method for controlling circulating current in a discharge condition of a multi-branch parallel battery pack.

[0139] The computer program product provided in this application can solve the technical problem of how to reduce the impact of circulating current caused by the end of the discharge condition. Compared with the prior art, the beneficial effects of the computer program product provided in this application are the same as the beneficial effects of the circulating current control method for the discharge condition of a multi-branch parallel battery pack provided in the above embodiment, and will not be repeated here.

[0140] The above descriptions are only some embodiments of the present application, and are not intended to limit the patent scope of the present application. All equivalent structural changes made using the contents of the present application specification and drawings under the technical concept of the present application, or direct / indirect applications in other related technical fields are included in the patent protection scope of the present application.

Claims

1. A method for controlling circulating current in a multi-branch parallel battery pack under discharge conditions, characterized in that: The method includes: Detect the state of charge of the multi-branch parallel battery pack, and when the percentage of the remaining power to the total capacity is less than the preset percentage, detect the duration of the discharge condition; When the discharge condition lasts longer than a preset time, the discharge current limit is determined according to the discharge current difference between branches, the maximum allowable discharge current, the lowest single cell voltage of the branch with the maximum discharge current, the current discharge power, and the number of branches; When the duration of the discharge condition is not greater than a preset duration, the discharge current limit is determined according to the discharge current difference between the branches, the maximum allowable discharge current, and the lowest single cell voltage of the branch with the maximum discharge current.

2. The method according to claim 1, characterized in that The step of determining the discharge current limit according to the discharge current difference between branches, the maximum allowable discharge current, the lowest single cell voltage of the branch with the maximum discharge current, the current discharge power and the number of branches includes: Obtain the maximum allowable discharge current, the lowest single cell voltage of the branch with the maximum discharge current, the current discharge power, and the number of branches; Detecting a maximum discharge current and a minimum discharge current between branches, and obtaining a discharge current difference between branches according to the maximum discharge current and the minimum discharge current; Determine a single current reduction amount according to the product of the number of branches and a preset current value; When the lowest single cell voltage is greater than a first preset voltage and the current discharge power is greater than a preset power, the maximum discharge current is reduced according to the single current reduction amount until the discharge current difference between the branches meets the preset requirement, and the reduced maximum discharge current is determined as the discharge current limit.

3. The method according to claim 2, characterized in that The step of reducing the maximum discharge current according to the single current reduction amount until the difference in discharge current between the branches meets the preset requirement when the lowest single cell voltage is greater than the first preset voltage and the current discharge power is greater than the preset power, and using the reduced maximum discharge current as the discharge current limit includes: Subtract the single current reduction amount from the maximum discharge current to obtain a pending discharge current limit; When the lowest single cell voltage is greater than a first preset voltage and the current discharge power is greater than a preset power, the discharge current difference between the branches and the discharge duration are periodically detected. When it is detected that the discharge current difference between the branches is greater than the preset current difference and the discharge duration is greater than the preset duration, the undetermined discharge current limit is again reduced by the current single reduction amount. When it is detected that the discharge current difference between the branches is not greater than the preset current difference or the discharge duration is not greater than the preset duration, the pending discharge current limit is determined as the discharge current limit.

4. The method according to claim 3, characterized in that After the step of subtracting the single current reduction amount from the maximum discharge current to obtain the to-be-determined discharge current limit, the method further includes: Detecting the minimum cell voltage and the current discharge power; When the lowest cell voltage is not greater than the first preset voltage or the current discharge power is not greater than the preset power, the discharge current limit is calculated according to the preset power.

5. The method according to claim 1, characterized in that The step of determining the discharge current limit according to the discharge current difference between branches, the maximum allowable discharge current, and the lowest single cell voltage of the branch with the maximum discharge current comprises: Obtain the maximum allowable discharge current and the lowest single cell voltage of the branch with the maximum discharge current; Detecting a maximum discharge current and a minimum discharge current between branches, and obtaining a discharge current difference between branches according to the maximum discharge current and the minimum discharge current; When the lowest cell voltage is not greater than a second preset voltage, reducing the maximum discharge current according to the discharge current difference to obtain a discharge current limit; When the lowest cell voltage is greater than a second preset voltage, the maximum discharge current is determined as a discharge current limit.

6. The method according to claim 5, characterized in that The step of reducing the maximum discharge current according to the discharge current difference to obtain a discharge current limit comprises: Comparing the discharge current difference with a preset current difference, and determining a preset ratio according to the comparison result; Multiplying the maximum discharge current by a preset ratio to obtain a to-be-determined discharge current limit; Periodically detecting the difference between the lowest cell voltage and the discharge current, and when the lowest cell voltage is not greater than a third preset voltage, determining the preset ratio again according to a comparison result between the discharge current difference and the preset current difference; The pending discharge current limit is multiplied by the preset ratio again until the lowest cell voltage is greater than the third preset voltage, and the finally obtained pending discharge current limit is determined as the discharge current limit, wherein the third preset voltage is greater than the second preset voltage.

7. The method according to claim 6, characterized in that The step of comparing the discharge current difference with the preset current difference and determining the preset ratio according to the comparison result comprises: When the discharge current difference is greater than the preset current difference, taking the first preset ratio as the final preset ratio; When the discharge current difference is not greater than the preset current difference, a second preset ratio is used as the final preset ratio, wherein the second preset ratio is greater than the first preset ratio.

8. A circulating current control device for a multi-branch parallel battery pack under discharge condition, characterized in that: The device comprises: A state detection module is used to detect the state of charge of a multi-branch parallel battery pack, and when the percentage of the remaining power to the total capacity is less than a preset percentage, detect the duration of the discharge condition; A first determination module is used to determine the discharge current limit according to the discharge current difference between branches, the maximum allowable discharge current, the lowest single cell voltage of the branch with the maximum discharge current, the current discharge power and the number of branches when the discharge condition lasts for a period longer than a preset period; The second determination module is used to determine the discharge current limit according to the discharge current difference between branches, the maximum allowable discharge current, and the lowest single cell voltage of the branch with the maximum discharge current when the discharge condition lasts for no longer than a preset time.

9. A circulating current control device for a multi-branch parallel battery pack under discharge condition, characterized in that: The device comprises: a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the computer program is configured to implement the steps of the method for controlling circulating current of a multi-branch parallel battery pack under discharge conditions as described in any one of claims 1 to 7.

10. A storage medium, characterized in that: The storage medium is a computer-readable storage medium, and a computer program is stored on the storage medium. When the computer program is executed by a processor, the steps of the method for controlling the circulating current of a multi-branch parallel battery pack under discharge conditions as described in any one of claims 1 to 7 are implemented.

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