Parallel operation discharging method of multiple battery packs, electronic equipment and battery packs

Abstract

The parallel operation discharging method for the multiple battery packs comprises the steps that the current difference value between the discharging overcurrent threshold value of each battery pack and the actual discharging current is obtained, and a current difference value set is obtained; determining a first current value, wherein the first current value is the minimum value in the current difference value set; in response to the condition that the first current value is greater than or equal to a first current threshold value, controlling the total discharge current of the plurality of battery packs to be kept unchanged, or controlling the total discharge current of the plurality of battery packs to be increased; or, determining the number of the current difference values in the current difference value set, and defining the number as a first number; calculating the number of current differences greater than or equal to the first current threshold, and defining the number as a second number; calculating a ratio of the second number to the first number, and defining the ratio as a first ratio; in response to the fact that the first ratio is larger than or equal to a first percentage, the total discharge current of the multiple battery packs is controlled to be kept unchanged or increased, and the first percentage is larger than or equal to 80% and smaller than or equal to 100%; the first current threshold value is a positive number, and the total discharge current is the sum of currents output by the multiple battery packs.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of battery technology, and specifically to a method for discharging multiple battery packs in parallel, an electronic device, and a battery pack. Background Art

[0002] Multiple battery packs are connected in parallel within a battery system to increase capacity and extend the range of the device. For example, a battery system that powers a two-wheeled vehicle uses multiple battery packs connected in parallel to increase the vehicle's range.

[0003] During the discharge process of battery equipment, multiple battery packs are discharged in parallel. Currently, the discharge efficiency of multiple battery packs in parallel is low and the power provided is insufficient. Summary of the Invention

[0004] Some embodiments of the present application provide a parallel discharge method for multiple battery packs, an electronic device, and a battery pack. The parallel discharge method improves discharge efficiency and provides sufficient power.

[0005] In a first aspect, some embodiments of the present application provide a method for discharging multiple battery packs in parallel, obtaining the current difference between the discharge overcurrent threshold and the actual discharge current of each battery pack to obtain a current difference value set. A first current value is determined, and the first current value is defined as the minimum value in the current difference value set. In response to the first current value being greater than or equal to the first current threshold, the total discharge current of the multiple battery packs is controlled to remain unchanged, or the total discharge current of the multiple battery packs is controlled to increase. The first current threshold is a positive number, and the total discharge current is the sum of the currents output by the multiple battery packs.

[0006] In the above embodiment, the first current value is greater than or equal to a positive first current threshold, indicating that the actual discharge current of each of the multiple battery packs is less than the discharge overcurrent threshold of the battery pack, and thus the multiple battery packs may have relatively low discharge efficiency. Based on this, when the first current value is detected to be greater than or equal to the first current threshold, the total discharge current of the multiple battery packs is controlled to remain unchanged, which helps reduce the risk of overcurrent protection, thereby reducing the risk of overall discharge efficiency being reduced due to the occurrence of overcurrent protection. Alternatively, when the first current value is detected to be greater than or equal to the first current threshold, the total discharge current of the multiple battery packs is controlled to increase, thereby improving the discharge efficiency of the multiple battery packs, thereby ensuring that the power provided by the multiple battery packs is sufficient.

[0007] In one or more embodiments, the number of current difference values in the current difference value set is determined and defined as a first number. The number of current difference values that are greater than or equal to a first current threshold is calculated and defined as a second number. The ratio of the second number to the first number is calculated and defined as a first ratio. In response to the first ratio being greater than or equal to a first percentage, the total discharge current of the plurality of battery packs is controlled to remain unchanged or to increase, where 80% ≤ the first percentage ≤ 100%.

[0008] In the above embodiments, if the current difference is greater than or equal to a positive first current threshold, it indicates that the corresponding battery pack is discharging at a current less than the discharge overcurrent threshold, potentially resulting in relatively low discharge efficiency. In some embodiments, when a first percentage of battery packs are detected to have relatively low discharge efficiency, the total discharge current of the multiple battery packs is controlled to remain unchanged. This helps reduce the risk of the battery packs triggering overcurrent protection, thereby reducing the risk of overall discharge efficiency being reduced due to the battery pack overcurrent protection. In some embodiments, when a first percentage of battery packs are detected to have low discharge efficiency, the total discharge current of the multiple battery packs is controlled to increase, thereby improving the discharge efficiency of the multiple battery packs and ensuring sufficient power provided by the multiple battery packs. Furthermore, when 80% ≤ the first percentage ≤ 100%, i.e., when the number of battery packs with low discharge efficiency reaches the range [80%, 100%], the total discharge current is controlled to remain unchanged or increase, which helps reduce the overall discharge efficiency reduction caused by the discharge overcurrent protection of a particular battery pack.

[0009] In one or more embodiments, controlling the total discharge current of the multiple battery packs to increase includes controlling the total discharge current of the multiple battery packs to increase at a first rate. Compared to controlling the total discharge current to jump directly to a large current value, controlling the total discharge current to increase at the first rate helps reduce the risk of the battery packs triggering discharge overcurrent protection. This ensures higher discharge efficiency when discharging the multiple battery packs in parallel while reducing the risk of triggering discharge overcurrent protection. Consequently, the power provided by the multiple battery packs increases smoothly, helping to reduce the occurrence of poor braking of electrical equipment due to sudden power changes.

[0010] In one or more embodiments, after controlling the total discharge current of the plurality of battery packs to increase at a first rate for a period of time, the first rate is controlled to decrease. In response to the total discharge current increasing to the product of the median value of the allowable discharge current of each battery pack and the number of battery packs, the total discharge current is stopped from increasing.

[0011] In the above embodiment, the total discharge current first increases at a first rate and then at a smaller rate, thereby reducing the risk of the battery pack triggering discharge overcurrent protection. When the total discharge current is monitored to reach the product of the median value of the allowable discharge current of each battery pack and the number of battery packs, indicating that the total discharge current is approaching the discharge current upper limit of the multiple battery packs, the total discharge current is stopped from increasing to balance discharge efficiency and the risk of triggering discharge overcurrent protection.

[0012] In one or more embodiments, the first rate is positively correlated with the minimum value in the set of current difference values. In this embodiment, a positive minimum value in the current difference value indicates that the actual discharge current of the corresponding battery pack is closest to the discharge overcurrent threshold, and that the battery pack is at the greatest risk of triggering discharge overcurrent protection. Therefore, based on the battery pack with the greatest risk of triggering discharge overcurrent protection, the first rate is determined to be positively correlated with its current difference, thereby reducing the risk of triggering discharge overcurrent protection and improving discharge efficiency.

[0013] In one or more embodiments, 90% ≤ the first percentage ≤ 100%. That is, when the number of battery packs with slightly low discharge efficiency detected reaches the range [90%, 100%), the total discharge current of the multiple battery packs is controlled to remain unchanged or increase, which helps to reduce the phenomenon of reducing the overall discharge efficiency due to discharge overcurrent protection of a battery pack, thereby maintaining or improving the discharge efficiency.

[0014] In one or more embodiments, the method further includes: controlling the total discharge current of the plurality of battery packs to decrease in response to the first current value being between a second current threshold and a third current threshold, wherein the second current threshold is greater than or equal to zero, and the third current threshold is greater than the second current threshold and less than or equal to the first current threshold.

[0015] In this embodiment, the first current value is within the positive interval [second current threshold, third current threshold), and the third current threshold is less than or equal to the first current threshold, indicating that the actual discharge current of the battery pack is less than and close to the discharge overcurrent threshold, and there is a tendency for discharge overcurrent protection to occur. At this time, controlling the total discharge current of multiple battery packs to decrease can effectively reduce the risk of discharge overcurrent protection occurring.

[0016] In one or more embodiments, the method further includes: calculating the number of current differences between the second current threshold and the third current threshold, defining the number as a third number; calculating a ratio of the third number to the first number, defining the ratio as a second ratio; and controlling the total discharge current of the plurality of battery packs to decrease in response to the second ratio being greater than or equal to a second percentage, where 25% ≤ the second percentage ≤ 100%. The second current threshold is greater than or equal to zero, and the third current threshold is greater than the second current threshold and less than or equal to the first current threshold.

[0017] In the above embodiment, if the current difference is greater than or equal to the second current threshold (which is a positive number) and less than the third current threshold, it means that the corresponding battery pack is discharging at a current less than but close to the discharge overcurrent threshold, and has a tendency to trigger discharge overcurrent protection. When it is detected that the number of battery packs that have reached a second percentage have a tendency to trigger discharge overcurrent protection, the total discharge current of the multiple battery packs is controlled to decrease, thereby reducing the risk of triggering discharge overcurrent protection and the phenomenon of reduced discharge efficiency due to the occurrence of discharge overcurrent protection. In addition, when 25% ≤ the second percentage ≤ 100%, that is, when the number of battery packs that have a tendency to trigger discharge overcurrent protection reaches the range of [25%, 100%], controlling the total discharge current of the multiple battery packs to decrease can effectively reduce the risk of triggering discharge overcurrent protection and maintain a relatively high discharge efficiency.

[0018] In one or more embodiments, controlling the total discharge current of the plurality of battery packs to decrease includes: controlling the total discharge current of the plurality of battery packs to decrease at a second rate until the total discharge current value of the plurality of battery packs reaches a first target current value.

[0019] In the above embodiment, the total discharge current decreases at the second rate to the first target current value. On the one hand, the total discharge current is reduced to reduce the risk of discharge overcurrent protection. On the other hand, the reduction is stopped after the total discharge current is reduced to the first target current value to avoid excessive reduction in discharge efficiency, thereby maintaining a certain discharge efficiency.

[0020] In one or more embodiments, the first target current value is defined as the product of the minimum of the first discharge current values of each battery pack in the plurality of battery packs and the number of battery packs. The first discharge current value of a battery pack is defined as the product of the allowable discharge current of the battery pack and a first coefficient, where 0<first coefficient<1.

[0021] In the above embodiment, the first discharge current value of the battery pack is less than the allowable discharge current of the battery pack, and the first target current value is less than the sum of the allowable discharge currents of each battery pack. Therefore, when the total discharge current is reduced to the first target current value, the risk of discharge overcurrent protection can be effectively reduced.

[0022] In one or more embodiments, the first coefficient is positively correlated with the minimum value in the current difference set. In this embodiment, a positive minimum value in the current difference set indicates that the actual discharge current of the corresponding battery pack is closest to the discharge overcurrent threshold, and that the battery pack is at the greatest risk of triggering discharge overcurrent protection. Therefore, based on the battery pack with the greatest risk of triggering discharge overcurrent protection, the first coefficient is determined to be positively correlated with its current difference, thereby reducing the risk of triggering discharge overcurrent protection while maintaining high discharge efficiency.

[0023] In one or more embodiments, the second rate is negatively correlated with the minimum value in the current difference set. In this embodiment, a positive minimum value in the current difference set indicates that the actual discharge current of the corresponding battery pack is closest to the discharge overcurrent threshold, and that the battery pack is at the greatest risk of triggering discharge overcurrent protection. Therefore, by using the battery pack with the greatest risk of triggering discharge overcurrent protection as a benchmark, determining a second rate that is negatively correlated with its current difference can reasonably reduce the total discharge current, balancing the risk of triggering overcurrent protection with maintaining high discharge efficiency.

[0024] In one or more embodiments, 50% ≤ the second percentage ≤ 100%. That is, when the number of battery packs with a tendency to trigger discharge overcurrent protection reaches the range of [50%, 100%], the total discharge current of the multiple battery packs is controlled to decrease, which can effectively reduce the risk of triggering discharge overcurrent protection while maintaining a relatively high discharge efficiency.

[0025] In one or more embodiments, the method further includes: controlling the total discharge current of the plurality of battery packs to decrease in response to the first current value being between a fourth current threshold and a fifth current threshold, wherein the fifth current threshold is less than or equal to zero, and the fourth current threshold is less than the fifth current threshold.

[0026] In this embodiment, the first current value is within the negative interval [fourth current threshold, fifth current threshold), indicating that the actual discharge current of the battery pack is greater than the discharge overcurrent threshold, and there is a tendency for discharge overcurrent protection to occur. At this time, controlling the total discharge current of multiple battery packs to decrease can effectively reduce the risk of discharge overcurrent protection occurring.

[0027] In one or more embodiments, the method further includes: calculating a number of current differences between a fourth current threshold and a fifth current threshold, defining the number as a fourth number; calculating a ratio of the fourth number to the first number, defining the ratio as a third number; and controlling the total discharge current of the plurality of battery packs to decrease in response to the third ratio being greater than or equal to a third percentage, where 25% ≤ the third percentage ≤ 100%. The fifth current threshold is less than or equal to zero, and the fourth current threshold is less than the fifth current threshold.

[0028] In the above embodiment, if the current difference is greater than or equal to a negative fourth current threshold and less than or equal to a negative fifth current threshold, it indicates that the corresponding battery pack is discharging at a current greater than the discharge overcurrent threshold and has a tendency to trigger discharge overcurrent protection. When a third percentage of battery packs are detected as having a tendency to trigger discharge overcurrent protection, the total discharge current of the multiple battery packs is controlled to decrease, thereby reducing the risk of triggering discharge overcurrent protection and the overall reduction in discharge efficiency caused by the triggering of discharge overcurrent protection. In addition, if 25% ≤ the third percentage ≤ 100%, that is, when the number of battery packs detected as having a tendency to trigger discharge overcurrent protection reaches the range of [25%, 100%], the total discharge current of the multiple battery packs is controlled to decrease to reduce the risk of triggering discharge overcurrent protection while maintaining a relatively high discharge efficiency.

[0029] In one or more embodiments, controlling the total discharge current of the plurality of battery packs to decrease includes: controlling the total discharge current of the plurality of battery packs to decrease at a third rate until the total discharge current value of the plurality of battery packs reaches a second target current value.

[0030] In the above embodiment, the total discharge current is reduced to the second target current value at a third rate. On the one hand, the total discharge current is reduced to reduce the risk of discharge overcurrent protection. On the other hand, the reduction is stopped after the total discharge current is reduced to the second target current value to avoid excessive reduction in discharge efficiency, thereby maintaining a certain discharge efficiency.

[0031] In one or more embodiments, the second target current value is defined as the product of the minimum of the second discharge current values of each battery pack in the plurality of battery packs and the number of battery packs. The second discharge current value of a battery pack is defined as the product of the allowable discharge current of the battery pack and a second coefficient, where 0<second coefficient<1.

[0032] In the above embodiment, the second discharge current value of the battery pack is less than the allowable discharge current of the battery pack, and the second target current value is less than the sum of the allowable discharge currents of each battery pack. Therefore, when the total discharge current is reduced to the second target current value, the risk of discharge overcurrent protection can be effectively reduced.

[0033] In one or more embodiments, the second coefficient is positively correlated with the minimum value in the current difference set. In this embodiment, a negative minimum value in the current difference set indicates that the actual discharge current of the corresponding battery pack is greater than the discharge overcurrent threshold, and the battery pack is at the greatest risk of triggering discharge overcurrent protection. Therefore, based on the battery pack with the greatest risk of triggering discharge overcurrent protection, the second coefficient is determined to be positively correlated with its battery difference. This second coefficient helps reduce the risk of triggering discharge overcurrent protection while maintaining high discharge efficiency.

[0034] In one or more embodiments, the third rate is negatively correlated with the minimum value in the current difference set. In this embodiment, a negative minimum value in the current difference set indicates that the actual discharge current of the corresponding battery pack is greater than the discharge overcurrent threshold, and the battery pack is at the greatest risk of triggering discharge overcurrent protection. Therefore, by using the battery pack with the greatest risk of triggering discharge overcurrent protection as a benchmark, determining a third rate that is negatively correlated with its current difference can reasonably reduce the total discharge current, balancing the risk of triggering overcurrent protection with maintaining high discharge efficiency.

[0035] In one or more embodiments, 50% ≤ the third percentage ≤ 100%. That is, when the number of battery packs with a risk of triggering discharge overcurrent protection reaches the range of [50%, 100%], the total discharge current of the multiple battery packs is controlled to decrease, which can effectively reduce the risk of triggering discharge overcurrent protection while maintaining a relatively high discharge efficiency.

[0036] In one or more embodiments, the method further includes: controlling the total discharge current of the plurality of battery packs to decrease in response to the first current value being less than a sixth current threshold, wherein the sixth current threshold is less than or equal to the fourth current threshold.

[0037] In the above embodiment, the first current value is less than the negative sixth current threshold, and the sixth current threshold is less than or equal to the fourth current threshold, indicating that the actual discharge current of the battery pack exceeds the discharge overcurrent threshold to a relatively large extent, and the risk of discharge overcurrent protection occurring is relatively high. At this time, controlling the total discharge current of multiple battery packs to decrease can effectively reduce the risk of discharge overcurrent protection occurring.

[0038] In one or more embodiments, the method further includes calculating a number of battery packs for which the current difference is less than or equal to a sixth current threshold, defining the number as a fifth number. Calculating a ratio of the fifth number to the first number, defining the ratio as a fourth ratio. In response to the fourth ratio being greater than or equal to a fourth percentage, controlling the total discharge current of the plurality of battery packs to decrease, where 25% ≤ the fourth percentage ≤ 100%. The sixth current threshold is less than or equal to the fourth current threshold.

[0039] In the above embodiment, the current difference is less than or equal to the negative sixth current threshold, and the sixth current threshold is less than or equal to the fourth current threshold, indicating that the corresponding battery pack is discharging at a current that significantly exceeds the discharge overcurrent threshold, and the risk of discharge overcurrent protection is high. When the risk of discharge overcurrent protection occurring is high for the battery packs that have reached the fourth percentage, the total discharge current of the multiple battery packs is controlled to decrease, thereby reducing the risk of discharge overcurrent protection occurring and reducing the phenomenon of reduced discharge efficiency due to discharge overcurrent protection. In addition, when 25% ≤ the fourth percentage ≤ 100%, that is, when the number of battery packs with a high risk of discharge overcurrent protection occurring reaches the range of [25%, 100%], the total discharge current of the multiple battery packs is controlled to decrease, which can effectively reduce the risk of discharge overcurrent protection occurring and maintain relatively high discharge efficiency.

[0040] In one or more embodiments, controlling the total discharge current of the plurality of battery packs to decrease includes: controlling the total discharge current of the plurality of battery packs to decrease at a fourth rate until the total discharge current value of the plurality of battery packs reaches a third target current value.

[0041] In the above embodiment, the total discharge current decreases to the third target current value at the fourth rate. On the one hand, the total discharge current is reduced to reduce the risk of discharge overcurrent protection. On the other hand, the reduction is stopped after decreasing to the third target current value to avoid excessive reduction in discharge efficiency, thereby maintaining a certain discharge efficiency.

[0042] In one or more embodiments, the third target current value is defined as the product of the minimum value of the third discharge current values of each battery pack in the plurality of battery packs and the first number. The third discharge current value of the battery pack is defined as the product of the allowable discharge current of the battery pack and a third coefficient, where 0<third coefficient<1.

[0043] In the above embodiment, the third discharge current of the battery pack is less than the allowable discharge current of the battery pack, and the third target current value is less than the sum of the allowable discharge currents of each battery pack. Therefore, when the total discharge current is reduced to the third target current value, the risk of discharge overcurrent protection can be effectively reduced.

[0044] In one or more embodiments, the third coefficient is positively correlated with the minimum value in the current difference set. In this embodiment, a negative minimum value in the current difference set indicates that the actual discharge current of the corresponding battery pack is greater than the discharge overcurrent threshold, and the battery pack is at the greatest risk of triggering the discharge overcurrent protection. Therefore, the third coefficient is determined to be positively correlated with the current difference of the battery pack with the greatest risk of triggering the discharge overcurrent protection, thereby reducing the risk of triggering the discharge overcurrent protection while maintaining high discharge efficiency.

[0045] In one or more embodiments, the fourth rate is negatively correlated with the minimum value in the current difference set. In this embodiment, a negative minimum value in the current difference set indicates that the actual discharge current of the corresponding battery pack is greater than the discharge overcurrent threshold, and the battery pack is at the greatest risk of triggering discharge overcurrent protection. Therefore, by using the battery pack with the greatest risk of triggering discharge overcurrent protection as a benchmark, determining the fourth rate as negatively correlated with its current difference can reasonably reduce the total discharge current, balancing the reduction in the risk of triggering overcurrent protection with maintaining high discharge efficiency.

[0046] In one or more embodiments, 50% ≤ the fourth percentage ≤ 100%. That is, when it is detected that the number of battery packs with a high risk of triggering discharge overcurrent protection reaches the range [50%, 100%), the total discharge current of the multiple battery packs is controlled to decrease, which can effectively reduce the risk of triggering discharge overcurrent protection while maintaining a relatively high discharge efficiency.

[0047] In a second aspect, some embodiments of the present application further provide an electronic device comprising a communication unit for transmitting a set of current difference values; a control unit communicatively connected to the communication unit, and the control unit is configured to execute the parallel discharge method of multiple battery packs in the first aspect.

[0048] In a third aspect, some embodiments of the present application further provide a battery pack, comprising the electronic device in the second aspect.

[0049] In a fourth aspect, some embodiments of the present application further provide an electrical device, including the electronic device in the second aspect.

[0050] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] One or more embodiments are exemplarily described by the figures in the accompanying drawings, which are not intended to limit the embodiments. Elements with the same reference numerals in the drawings represent similar elements.

[0052] Figure 1 A schematic diagram of a battery management system provided in an embodiment of the present application;

[0053] Figure 2 The process of the parallel discharge method of multiple battery packs provided in the embodiment of the present application Figure 1 ;

[0054] Figure 3 Schematic diagram of dynamically adjusting the total discharge current in the parallel discharge method provided in the embodiment of the present application Figure 1 ;

[0055] Figure 4 The process of the parallel discharge method of multiple battery packs provided in the embodiment of the present application Figure 2 ;

[0056] Figure 5 The process of the parallel discharge method of multiple battery packs provided in the embodiment of the present application Figure 3 ;

[0057] Figure 6 The process of the parallel discharge method of multiple battery packs provided in the embodiment of the present application Figure 4 ;

[0058] Figure 7 The process of the parallel discharge method of multiple battery packs provided in the embodiment of the present application Figure 5 ;

[0059] Figure 8 The process of the parallel discharge method of multiple battery packs provided in the embodiment of the present application Figure 6 ;

[0060] Figure 9 The process of the parallel discharge method of multiple battery packs provided in the embodiment of the present application Figure 7 . DETAILED DESCRIPTION

[0061] To make the objectives, technical solutions, and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, not all of them. It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application.

[0062] It should be noted that when an element is described as being "connected" to another element, it may be directly connected to the other element, or one or more intermediate elements may be present therebetween. In addition, the technical features involved in the various embodiments of the present application described below may be combined with each other as long as there is no structural conflict between them.

[0063] Currently, secondary batteries are widely used in electrical devices such as electric bicycles, electric motorcycles, drones, and electric vehicles. The inventors of this application have noted that to expand the capacity and improve the endurance of electrical devices, two or more battery packs are often used in parallel. Multiple battery packs discharge in parallel to provide power for the electrical device.

[0064] During the parallel discharge process of multiple battery packs, the battery packs or electrical equipment determine the total discharge current based on the parallel status of the battery packs. The multiple battery packs output current in response to the total discharge current, and the sum of the currents output by the multiple battery packs is the total discharge current.

[0065] However, when multiple parallel battery packs provide a total discharge current for an electrical device, the actual discharge current of each battery pack varies. Some battery packs may experience actual discharge currents exceeding their own discharge overcurrent thresholds, potentially triggering discharge overcurrent protection. Battery packs experiencing discharge overcurrent protection interrupt discharge, reducing the overall power provided by the multiple battery packs and leading to lower discharge efficiency, impacting the operation of the electrical device. For example, an electric bicycle may experience stalling, slowing down, or difficulty climbing hills.

[0066] To reduce the risk of discharge overcurrent protection, some parallel discharge solutions use a smaller total discharge current to control the discharge of multiple battery packs in parallel. The actual discharge current of each battery pack is less than or significantly less than its own discharge overcurrent threshold, thus reducing the risk of discharge overcurrent protection. However, this solution has low discharge efficiency.

[0067] To improve discharge efficiency, some parallel discharge solutions use the cumulative allowable discharge current of each battery pack, or the product of the minimum allowable discharge current of each pack and the number of packs, as the total discharge current. However, due to differences in aging, temperature, or internal resistance among battery packs, some packs may have actual discharge currents exceeding their discharge overcurrent threshold, easily triggering discharge overcurrent protection. Other packs may have actual discharge currents below their discharge overcurrent threshold, resulting in low discharge efficiency.

[0068] Based on this, some embodiments of the present application provide a parallel discharge method for multiple battery packs, an electronic device, a battery pack, and an electrical device. The parallel discharge method is executed by the electronic device, so that the discharge efficiency of the multiple battery packs is improved.

[0069] In some embodiments, the electronic device is a battery management system (BMS) for a primary battery pack. The primary battery pack is the battery pack with the largest or smallest address among multiple parallel battery packs. In other embodiments, the electronic device is a control system within an electric device, such as an electric vehicle.

[0070] Taking the electric motorcycle as an example, the electrical equipment is connected to the aviation plug interface of the electric motorcycle. The aviation plug interface of the battery pack includes: ID1 and ID2 signal interfaces. When the ID signal interface is short-circuited with the positive power terminal P+ of the vehicle aviation plug interface, the battery pack confirms that the ID signal interface is 1. When the ID signal interface is not short-circuited with the positive power terminal P+ of the vehicle aviation plug interface, the battery pack confirms that the ID signal is 0. For example, battery pack 1# recognizes that its ID1 and ID2 are both short-circuited with P+, then the address of battery pack 1# is (1,1), battery pack 2# recognizes that only ID1 is short-circuited with P+, then the address of battery pack 2# is (1,0), battery pack 3# recognizes that only ID2 is short-circuited with P+, then the address of battery pack 3# is (0,1). In some embodiments, the battery pack with the largest address is the main battery pack, and battery pack 1# is the main battery pack.

[0071] See also Figure 1 The battery management system 10 includes a communication unit 11 and a control unit 12. The control unit 12 is in communication connection with the communication unit 11.

[0072] In some embodiments, the control unit 12 includes a memory 121, a processor 122, and a computer program stored in the memory 121 and running on the processor 122. The communication unit 11, the memory 121, and the processor 122 are connected via a bus 13 and communicate with each other.

[0073] The communication unit 11 is mainly used to realize the communication between the modules, devices, units and / or devices in the embodiments of the present application. In some embodiments, the input device and / or output device are accessed through the communication unit 11.

[0074] In some embodiments, the processor 122 includes a central processing unit (CPU), a microcontroller unit (MCU), or an application-specific integrated circuit (ASIC), or is configured to implement one or more integrated circuits of the embodiments of the present application.

[0075] The memory 121 includes a read-only memory (ROM), a random access memory (RAM), a magnetic disk storage medium device, an optical storage medium device, a flash memory device, an electrical, optical, or other physical / tangible memory storage device. Therefore, typically, the memory 121 includes one or more tangible (non-transitory) computer-readable storage media (e.g., a memory device) encoded with software including computer-executable instructions, and when the software is executed (e.g., by one or more processors 122), it is operable to perform the method for parallel discharging of multiple battery packs described below.

[0076] The processor 122 runs a computer program corresponding to the executable program code by calling the executable program code stored in the memory 121 to implement the parallel discharge method of multiple battery packs described below.

[0077] It should be noted that although the above BMS10 only shows the memory 121, the processor 122, and the communication unit 11, in the specific implementation process, those skilled in the art should understand that the BMS10 may also include other devices necessary for normal operation. At the same time, according to specific needs, those skilled in the art should understand that the BMS10 may also include hardware devices that implement other additional functions. In addition, those skilled in the art should understand that the BMS10 may also include only the devices necessary to implement the embodiments of the present application, and does not necessarily include Figure 1 All devices shown in .

[0078] In some embodiments, the electronic device is a controller of an electric device, and the controller includes a communication unit and a control unit, wherein the control unit is communicatively connected with the communication unit.

[0079] The communication unit is mainly used to realize the communication between the modules, devices, units and / or devices in the embodiments of the present application. In some embodiments, the input device and / or output device are accessed through the communication unit.

[0080] In this embodiment, the structure and function of the control unit are the same as those of the control unit 12 in the above embodiment, and are not described in detail here.

[0081] The above article introduces the hardware foundation of electronic devices. The following describes the method for electronic devices to perform parallel discharge of multiple battery packs.

[0082] The parallel discharge method for multiple battery packs provided in the embodiments of this application is implemented in an electronic device having the aforementioned hardware structure. The electronic device is a battery management system (BMS) for a primary battery pack, or a controller in an electrical device. The following uses the BMS of a primary battery pack as an example to illustrate the above method. The BMS described in the following embodiments is the BMS of a primary battery pack.

[0083] like Figure 2 As shown, in some embodiments of the present application, the method for discharging multiple battery packs in parallel includes the following steps S210 to S230:

[0084] Step S210: obtaining the current difference between the discharge overcurrent threshold and the actual discharge current of each battery pack to obtain a current difference set.

[0085] Specifically, the electrical equipment is started, and multiple battery packs are connected in parallel to provide power to the electrical equipment. The BMS determines the total discharge current based on the parallel status of the multiple battery packs, and the sum of the actual discharge currents of each battery pack is the total discharge current. The BMS of the battery pack determines the discharge overcurrent threshold. The discharge overcurrent threshold is a threshold used to distinguish whether the battery pack triggers overcurrent protection. For example, the discharge overcurrent threshold is the maximum safe current value allowed to be output by the battery pack during the discharge process. In some embodiments, the discharge overcurrent threshold is a static threshold, which is obtained from the battery pack label, battery module label, packaging, user manual, instruction manual, advertising, marketing or other supporting documents. In some embodiments, the discharge overcurrent threshold is a dynamic threshold, and the BMS dynamically adjusts it based on the temperature, state of charge and aging of the battery pack.

[0086] The current difference between the discharge overcurrent threshold and the actual discharge current reflects the discharge status of the battery pack. Here, the current difference is equal to the discharge overcurrent threshold minus the actual discharge current. If the current difference is positive, it means the actual discharge current is less than the discharge overcurrent threshold, and the discharge overcurrent protection will not occur. If the actual discharge current is less than the discharge overcurrent threshold to a certain extent, it indicates that the battery pack's discharge efficiency is low. If the current difference is negative, it means the actual discharge current is greater than the discharge overcurrent threshold, and there is a risk of the discharge overcurrent protection triggering.

[0087] In some embodiments, the battery pack's BMS collects the pack's actual discharge current and calculates the current difference between the discharge overcurrent threshold and the actual discharge current. Based on communication connections between the BMSs of multiple battery packs, each slave pack's BMS calculates its own current difference and sends it to the master pack's BMS. The master pack's BMS then obtains the current difference of each slave pack, generating a current difference set.

[0088] Step S220: determining a first current value, where the first current value is defined as a minimum value in the current difference value set.

[0089] Step S230 : in response to the first current value being greater than or equal to the first current threshold, controlling the total discharge current of the plurality of battery packs to remain unchanged, or controlling the total discharge current of the plurality of battery packs to increase.

[0090] Among them, the first current threshold is characterized as a current threshold for monitoring a lower discharge efficiency, and the first current threshold is a positive number. In some embodiments, the first current threshold is 5A or 6A, etc. It is understandable that those skilled in the art set the first current threshold according to the actual situation of the battery equipment, and this application does not make specific limitations here. If the first current value is greater than or equal to the first current threshold, it means that the battery pack is discharging with a smaller current that is lower than the discharge overcurrent threshold, and has a lower discharge efficiency.

[0091] like Figure 3As shown, the current difference values corresponding to each battery pack constitute a current difference value set. The main battery pack BMS determines that the minimum value in the current difference value set is a first current value. The main battery pack BMS monitors the first current value. If the first current value is greater than or equal to the first current threshold, it determines that the multiple battery packs have relatively low discharge efficiency, and then executes one of the following two methods: (1) Request to keep the total discharge current of the multiple battery packs unchanged to reduce the risk of overcurrent protection, thereby reducing the risk of overall discharge efficiency reduction due to overcurrent protection; (2) Request to increase the total discharge current of the multiple battery packs to improve the discharge efficiency of the multiple battery packs, so that the multiple battery packs provide more power.

[0092] In some embodiments, controlling the total discharge current of the multiple battery packs to increase in step S230 includes the following steps: controlling the total discharge current of the multiple battery packs to increase at a first rate. That is, when the master battery pack BMS detects that the first current value is greater than or equal to a first current threshold, it requests the total discharge current to increase at the first rate, where the first rate is the rate of increase of the total discharge current.

[0093] Compared to controlling the total discharge current to jump directly to a high current value, controlling the total discharge current to increase at the first rate helps reduce the risk of sudden discharge overcurrent protection triggering of the battery pack. This not only ensures higher discharge efficiency when discharging multiple battery packs in parallel, but also reduces the risk of triggering discharge overcurrent protection. As a result, the power provided by multiple battery packs increases smoothly, helping to reduce the risk of improper braking of electrical equipment caused by sudden power changes.

[0094] Exemplarily, when the battery device starts discharging, the main battery pack BMS determines the total discharge current I as the initial value linit, that is, I = linit. In some embodiments, the main battery pack BMS determines the initial value linit according to linit = N * Imin, where N is the number of parallel battery packs and Imin is the minimum value of the allowable discharge current of each battery pack. Specifically, each slave battery pack BMS determines its own allowable discharge current according to the SOP table and sends it to the BMS of the main battery pack. In this way, the main battery pack BMS obtains the allowable discharge current of each battery pack, and the main battery pack BMS calculates the initial value linit based on the product of the minimum value Imin of the allowable discharge current of each battery pack and the number N of parallel battery packs, that is, linit = N × Imin. It is understandable that in other embodiments, the initial value linit is set by other means, such as setting the initial value linit to a fixed value, and the initial value linit is sufficient so that overcurrent protection does not occur during the discharge process.

[0095] The battery pack continues to power the entire vehicle. If the first current value detected at time t1 is greater than or equal to the first current threshold, a request is made to increase the total discharge current of the multiple battery packs at a first rate. In some embodiments, the total discharge current is expressed by the following formula: I'=I+V1×Δt. Among them, I is the total discharge current before increasing at the first rate, V1 is the first rate, Δt is the time for increasing the total discharge current, and I' is the total discharge current after increasing at the first rate. In some embodiments, Δt=t-t1, t is the current moment, and t1 is the moment when the first current value is detected to be greater than or equal to the first current threshold.

[0096] In some embodiments, to prevent over-discharge caused by excessive total discharge current, a condition is set to stop increasing the total discharge current. Exemplarily, the main battery pack BMS calculates the product of the median allowable discharge current of each battery pack and the number of battery packs. In response to the total discharge current increasing to equal this product, the total discharge current is stopped from increasing. It is understood that the median allowable discharge current of each battery pack can be one of the following two values: the median allowable discharge current of each battery pack or the average allowable discharge current of each battery pack.

[0097] In some embodiments, the product of the median allowable discharge current of each battery pack and the number of battery packs is used to represent the upper limit of the discharge current for the multiple battery packs. If the total discharge current increases to this product, it indicates that the total discharge current is approaching the upper limit of the discharge current for the multiple battery packs. Therefore, the total discharge current of the multiple battery packs is stopped from increasing to prevent over-discharge. This means that each battery pack has high discharge efficiency and a low risk of overcurrent protection.

[0098] As can be seen from the above, the total discharge current increases at a first rate from the time it starts to increase until it stops increasing. In some embodiments, the first rate can be variable or constant during the period of increase in the total discharge current. It is understood that if the first rate is too high, overdischarge and overcurrent protection may occur in the later stages of the total discharge current increase.

[0099] In some embodiments, to reduce the risk of overcurrent protection during the later stages of the increase, after the total discharge current increases at a first rate for a period of time, a request is made to reduce the first rate, thereby gradually slowing the increase in the total discharge current. This allows the discharge current of each battery pack to increase smoothly, helping to reduce overdischarge and overcurrent protection, and improving discharge efficiency and effectiveness.

[0100] In some embodiments, the minimum value in the current difference set is positively correlated with the first rate. In this embodiment, a positive minimum value in the current difference set indicates that the corresponding battery pack's discharge overcurrent threshold is closest to its actual discharge current, and that the battery pack is relatively more likely to trigger overcurrent protection. Therefore, the first rate is determined to be a positively correlated function of the current difference, using the battery pack with the greatest tendency to trigger overcurrent protection as a benchmark. That is, the smaller the minimum value in the current difference set, the closer the actual discharge current of each battery pack is to the discharge overcurrent threshold, and the smaller the first rate. The larger the minimum value in the current difference set, the farther the actual discharge current of each battery pack is from the discharge overcurrent threshold, and the larger the first rate. This ensures that the first rate reduces the risk of triggering discharge overcurrent protection and improves discharge efficiency.

[0101] Exemplarily, the minimum value in the current difference set and the first rate exhibit the following positive correlation function: V1 = k × ΔI_min × N, where V1 is the first rate, ΔI_min is the minimum value in the current difference set, N is the number of battery packs, and 0 < k < 1. For example, k is 0.5, meaning that the first rate is the product of half the minimum value in the current difference set and the number of battery packs.

[0102] In some embodiments, the parallel discharge method further includes the following step: in response to the first current value being between the second current threshold and the third current threshold, controlling the total discharge current of the plurality of battery packs to decrease.

[0103] The first current value is in the positive interval [second current threshold, third current threshold), and the third current threshold is less than or equal to the first current threshold, indicating that the actual discharge current of the battery pack is less than and close to the discharge overcurrent threshold, and there is a tendency for discharge overcurrent protection to occur. At this time, controlling the total discharge current of multiple battery packs to decrease can effectively reduce the risk of discharge overcurrent protection. In some embodiments, [second current threshold, third current threshold) is [0A, 5A). It can be understood that those skilled in the art can set the second current threshold and the third current threshold according to the actual situation of the battery equipment, and this application does not make specific limitations here.

[0104] In some embodiments, the specific implementation process of controlling the total discharge current of multiple battery packs to decrease in the above steps includes the following steps: controlling the total discharge current of multiple battery packs to decrease at a second rate until the total discharge current value of the multiple battery packs reaches a first target current value.

[0105] Among them, the second rate is the rate of reduction of the total discharge current, that is, the total discharge current decreases at the second rate. When the first current value is monitored to be between the second current threshold and the third current threshold, the total discharge current decreases at the second rate. Compared with requesting the total discharge current to jump directly to a smaller current value, requesting the total discharge current to be reduced at the second rate reduces the risk of overcurrent and ensures discharge efficiency. At the same time, when the total discharge current jumps directly to a smaller current value, electrical equipment such as electric motorcycles may experience a sense of frustration. However, requesting the total discharge current to be reduced at the second rate reduces the sense of frustration of the electric motorcycle and improves the user experience.

[0106] For example, when the main battery pack detects at time t2 that the first current value is between the second current threshold and the third current threshold, the total discharge current I is obtained, and a request is made to reduce the total discharge current of the multiple battery packs at the second rate. That is, the total discharge current can be expressed using the following formula: I" = I - V2 × Δt, where I is the total discharge current before being reduced at the second rate, V2 is the second rate, Δt is the time for reducing the total discharge current, and I" is the total discharge current after being reduced at the second rate. In some embodiments, Δt = t - t2, where t is the current time and t2 is the time when the first current value is detected to be between the second current threshold and the third current threshold.

[0107] In some embodiments, to prevent low discharge efficiency due to excessively reduced total discharge current, a condition is set for stopping the reduction of the total discharge current. For example, the main battery pack BMS determines in real time or at intervals whether the total discharge current value of multiple battery packs is equal to a first target current value. If the total discharge current value is equal to the first target current value, the total discharge current of the multiple battery packs is stopped from being reduced to avoid excessive reduction in discharge efficiency, thereby maintaining a certain discharge efficiency and providing the required power for the battery device. The first target current value is a positive number and is the current threshold for stopping the reduction of the total discharge current.

[0108] As can be seen from the above, the total discharge current decreases at a second rate from the start of the decrease to the stop of the decrease. In some embodiments, the second rate can be variable or constant during the decrease of the total discharge current. It is understood that if the second rate is too high, low discharge efficiency may occur in the later stages of the decrease of the total discharge current.

[0109] In some embodiments, to prevent low discharge efficiency in the later stages of a reduction, a request is made to reduce the second rate in response to a decrease in the total discharge current. That is, after the total discharge current has decreased at the second rate for a period of time, the request is made to reduce the second rate so that the decrease in the total discharge current gradually slows. This allows the discharge current of each battery pack to decrease smoothly, helping to reduce overcurrent risks while maintaining high discharge efficiency.

[0110] In some embodiments, the second rate is negatively correlated with the minimum value in the current difference set. In these embodiments, a positive minimum value in the current difference set indicates that the actual discharge current of one battery pack is closest to the discharge overcurrent threshold and that this battery pack is at the greatest risk of triggering discharge overcurrent protection. Therefore, based on the battery pack with the greatest risk of triggering discharge overcurrent protection, the second rate is determined to be negatively correlated with its current difference, thereby appropriately reducing the total discharge current and balancing the risk of triggering overcurrent protection with maintaining high discharge efficiency.

[0111] In some embodiments, the first target current value is defined as the product of the minimum value of the first discharge current values of each battery pack in a plurality of battery packs and the number of battery packs; the first discharge current value of the battery pack is defined as the product of the allowable discharge current of the battery pack and a first coefficient, 0<first coefficient<1.

[0112] Since the first coefficient is in the interval (0, 1), the first discharge current value of the battery pack is less than the allowable discharge current of the battery pack, and the first target current value is less than the sum of the allowable discharge currents of each battery pack. Therefore, when the total discharge current is reduced to the first target current value, the risk of discharge overcurrent protection is reduced.

[0113] In some embodiments, the first coefficient is positively correlated with the minimum value in the current difference set. In this embodiment, the minimum value in the current difference set is a positive number, indicating that the actual discharge current of one battery pack is closest to the discharge overcurrent threshold and that this battery pack is at the greatest risk of triggering discharge overcurrent protection. Therefore, based on the battery pack with the greatest risk of triggering discharge overcurrent protection, the first coefficient is determined to be positively correlated with the minimum value in the current difference set. This helps reduce the risk of triggering discharge overcurrent protection while maintaining high discharge efficiency.

[0114] In some embodiments, current thresholds are set in stages to reduce the total discharge current in stages. For example, the second and third current thresholds are set to establish a first decreasing stage for the total discharge current; the fourth and fifth current thresholds are set to establish a second decreasing stage for the total discharge current; and the sixth current threshold is set to establish a third decreasing stage for the total discharge current. [Fourth current threshold, fifth current threshold) is a negative interval, such as [-20A, 0A); the sixth current threshold is a negative number, such as -20A.

[0115] The main battery pack BMS monitors whether the trigger conditions for the three stages mentioned above are met. If the trigger conditions for the first decreasing stage are met, the program for reducing the total discharge current at the second rate in the first decreasing stage is initiated. If the trigger conditions for the second decreasing stage are met, the program for reducing the total discharge current at the third rate in the second decreasing stage is initiated. If the trigger conditions for the third decreasing stage are met, the program for reducing the total discharge current at the fourth rate in the third decreasing stage is initiated. The trigger conditions for the first decreasing stage are: the first current value is between the second current threshold and the third current threshold; the trigger conditions for the second decreasing stage are: the first current value is between the fourth current threshold and the fifth current threshold; and the trigger conditions for the third decreasing stage are: the first current value is less than the sixth current threshold.

[0116] The specific implementation process of the second descent stage is as follows:

[0117] In some embodiments, the parallel discharge method further includes the following step: in response to the first current value being between a fourth current threshold and a fifth current threshold, controlling the total discharge current of the plurality of battery packs to decrease.

[0118] If the first current value is within the negative interval [fourth current threshold, fifth current threshold], and the fifth current threshold is less than or equal to zero, this indicates that the actual discharge current of the battery pack is greater than the discharge overcurrent threshold, indicating a tendency for discharge overcurrent protection to occur, or that discharge overcurrent protection may soon occur. In this case, the total discharge current of the multiple battery packs is controlled to decrease to reduce the risk of discharge overcurrent protection. It will be appreciated that those skilled in the art may set the fourth and fifth current thresholds based on the actual conditions of the battery equipment, and this application does not impose specific limitations thereon.

[0119] In some embodiments, the specific implementation process of controlling the total discharge current of multiple battery packs to decrease in the second decrease phase includes the following steps: controlling the total discharge current of multiple battery packs to decrease at a third rate until the total discharge current value of the multiple battery packs reaches a second target current value.

[0120] The third rate is the rate at which the total discharge current decreases. Specifically, the total discharge current decreases at the third rate. When the first current value is detected to be between the fourth and fifth current thresholds, the total discharge current decreases at the third rate. Compared to requesting the total discharge current to jump directly to a smaller current value, requesting the total discharge current to decrease at the third rate reduces the risk of overcurrent and ensures discharge efficiency.

[0121] Exemplarily, when the main battery pack detects at time t3 that the first current value is between the fourth current threshold and the fifth current threshold, the total discharge current I is obtained, and a request is made to reduce the total discharge current of the multiple battery packs at a third rate. That is, the total discharge current can be expressed by the following formula: I''=I-V3×Δt, where I is the total discharge current before being reduced at the third rate, V3 is the third rate, Δt is the time for reducing the total discharge current, and I'' is the total discharge current after being reduced at the third rate. In some embodiments, Δt=t-t3, where t is the current time and t3 is the time when the first current value is detected to be between the fourth current threshold and the fifth current threshold.

[0122] In some embodiments, the third rate is greater than the second rate to reduce the total discharge current faster than the first decrease stage, thereby causing the actual discharge current of multiple battery packs to drop rapidly, which is beneficial to reducing safety risks such as thermal runaway of the battery pack.

[0123] In some embodiments, to prevent the total discharge current from being reduced too little, leading to lower discharge efficiency, a condition is set for stopping the reduction of the total discharge current. For example, the main battery pack BMS determines in real time or at intervals whether the total discharge current value of multiple battery packs is equal to a second target current value. If the total discharge current value is equal to the second target current value, the total discharge current of the multiple battery packs is stopped from being reduced to avoid excessive reduction in discharge efficiency, thereby maintaining a certain discharge efficiency. The second target current value is a positive number and is the current threshold for stopping the reduction of the total discharge current.

[0124] As can be seen from the above, the total discharge current decreases at a third rate from the start of the decrease to the stop of the decrease. In some embodiments, the third rate can be variable or constant during the decrease of the total discharge current. It is understood that if the third rate is too high, low discharge efficiency may occur in the later stages of the decrease of the total discharge current.

[0125] In some embodiments, to prevent low discharge efficiency in the later stages of the total discharge current reduction, a request is made to reduce the third rate in response to the reduction in the total discharge current. That is, after the total discharge current has been decreasing at the third rate for a period of time, the request is made to reduce the third rate so that the reduction in the total discharge current gradually slows. This allows the discharge current of each battery pack to decrease smoothly, helping to reduce the risk of overcurrent while maintaining high discharge efficiency.

[0126] In some embodiments, the third rate is negatively correlated with the minimum value in the current difference set. In this embodiment, a negative minimum value in the current difference set indicates that the actual discharge current of one of the battery packs exceeds the discharge overcurrent threshold, and that this battery pack is at the greatest risk of triggering discharge overcurrent protection. Therefore, by using the battery pack with the greatest risk of triggering discharge overcurrent protection as a benchmark, determining a third rate that is negatively correlated with its current difference can reasonably reduce the total discharge current, balancing the risk of triggering overcurrent protection with maintaining high discharge efficiency.

[0127] In some embodiments, the second target current value is defined as the product of the minimum value of the second discharge current values of each battery pack in a plurality of battery packs and the number of battery packs; the second discharge current value of the battery pack is defined as the product of the allowable discharge current of the battery pack and a second coefficient, 0<second coefficient<1, and the second coefficient<first coefficient.

[0128] Since the second coefficient is in the interval (0, 1), the second discharge current value of the battery pack is less than the allowable discharge current of the battery pack, and the second target current value is less than the sum of the allowable discharge currents of each battery pack. Therefore, when the total discharge current is reduced to the second target current value, the risk of discharge overcurrent protection can be effectively reduced.

[0129] In some embodiments, the second coefficient is positively correlated with the minimum value in the current difference set. In this embodiment, a negative minimum value in the current difference set indicates that the actual discharge current of one of the battery packs exceeds the discharge overcurrent threshold, and that this battery pack is at the greatest risk of triggering discharge overcurrent protection. Therefore, based on the battery pack with the greatest risk of triggering discharge overcurrent protection, the second coefficient is determined to be positively correlated with its battery difference. This helps reduce the risk of triggering discharge overcurrent protection while maintaining high discharge efficiency.

[0130] The specific implementation process of the third descent stage is as follows:

[0131] In some embodiments, the parallel discharge method further includes the following step: in response to the first current value being less than a sixth current threshold, controlling the total discharge current of the plurality of battery packs to decrease.

[0132] If the first current value is less than the negative sixth current threshold, and the sixth current threshold is less than or equal to the fourth current threshold, this indicates that the actual discharge current of the battery pack exceeds the discharge overcurrent threshold to a relatively large extent, and the risk of triggering the discharge overcurrent protection is high. In this case, reducing the total discharge current of the multiple battery packs can effectively reduce the risk of triggering the discharge overcurrent protection. It is understood that those skilled in the art may set the sixth current threshold based on the actual situation of the battery equipment, and this application does not specifically limit this.

[0133] In some embodiments, the specific implementation process of controlling the total discharge current of multiple battery packs to decrease in the third decreasing stage includes the following steps: controlling the total discharge current of multiple battery packs to decrease at a fourth rate until the total discharge current value of the multiple battery packs reaches a third target current value.

[0134] The fourth rate is the rate at which the total discharge current decreases. When the main battery pack's BMS detects that the first current value is less than the sixth current threshold, the total discharge current decreases at the fourth rate. Compared to requesting the total discharge current to jump directly to a smaller current value, requesting the total discharge current to decrease at the fourth rate reduces overcurrent risk, ensures discharge efficiency, and smoothly reduces the total discharge current, minimizing impact on electrical equipment.

[0135] Exemplarily, when the main battery pack detects at time t4 that the first current value is less than the sixth current threshold, the total discharge current I is obtained and a request is made to reduce the total discharge current of the multiple battery packs at the fourth rate. That is, the total discharge current can be expressed using the following formula: I"" = I - V4 × Δt, where I is the total discharge current before being reduced at the fourth rate, V4 is the third rate, Δt is the time it takes to reduce the total discharge current, and I"" is the total discharge current after being reduced at the fourth rate. In some embodiments, Δt = t - t4, where t is the current time and t4 is the time when the first current value is detected to be less than the sixth current threshold.

[0136] In some embodiments, the fourth rate is greater than the third rate to reduce the total discharge current faster than the second decrease stage, thereby causing the actual discharge current of multiple battery packs to drop rapidly, which is beneficial to reducing safety risks such as thermal runaway of the battery pack.

[0137] In some embodiments, to prevent low discharge efficiency due to excessively reduced total discharge current, a condition is set for stopping the reduction of the total discharge current. For example, the main battery pack BMS determines in real time or at intervals whether the total discharge current of the multiple battery packs is equal to a third target current value. If the total discharge current value is equal to the third target current value, the total discharge current of the multiple battery packs is stopped from being reduced to avoid excessive reduction in discharge efficiency, thereby maintaining a certain discharge efficiency and providing appropriate power to the electrical equipment. The third target current value is a positive number and is the current threshold for stopping the reduction of the total discharge current.

[0138] As can be seen from the above, the total discharge current decreases at a fourth rate from the start of the decrease to the stop of the decrease. In some embodiments, the fourth rate can be variable or constant during the decrease of the total discharge current. It is understood that if the fourth rate is too high, low discharge efficiency may occur in the later stages of the decrease of the total discharge current.

[0139] In some embodiments, to prevent low discharge efficiency in the later stages of a discharge current reduction, a request is made to reduce the fourth rate in response to a decrease in the total discharge current. That is, after the total discharge current has decreased at the fourth rate for a period of time, the request is made to reduce the fourth rate so that the decrease in the total discharge current gradually slows. This allows the discharge current of each battery pack to decrease smoothly, helping to reduce overcurrent risks while maintaining high discharge efficiency.

[0140] In some embodiments, the fourth rate is negatively correlated with the minimum value in the current difference set. In this embodiment, a negative minimum value in the current difference set indicates that the actual discharge current of the corresponding battery pack is greater than the discharge overcurrent threshold, and that the battery pack is at the greatest risk of triggering discharge overcurrent protection. Therefore, by using the battery pack with the greatest risk of triggering discharge overcurrent protection as a benchmark, determining a fourth rate that is negatively correlated with its current difference can reasonably reduce the total discharge current, balancing the risk of triggering overcurrent protection with maintaining high discharge efficiency.

[0141] In some embodiments, the third target current value is defined as the product of the minimum value of the third discharge current values of each battery pack in a plurality of battery packs and the number of battery packs; the third discharge current value of the battery pack is defined as the product of the allowable discharge current of the battery pack and a third coefficient, 0<third coefficient<1, and the third coefficient<second coefficient.

[0142] Since the third coefficient is in the interval (0, 1), the third discharge current value of the battery pack is less than the allowable discharge current of the battery pack, and the third target current value is less than the sum of the allowable discharge currents of each battery pack. Therefore, when the total discharge current is reduced to the third target current value, the risk of discharge overcurrent protection can be effectively reduced.

[0143] In some embodiments, the third coefficient is positively correlated with the minimum value in the current difference set. In this embodiment, a negative minimum value in the current difference set indicates that the actual discharge current of the corresponding battery pack is greater than the discharge overcurrent threshold, and that the battery pack is at the greatest risk of triggering the discharge overcurrent protection. Therefore, the third coefficient is determined to be positively correlated with the current difference of the battery pack with the greatest risk of triggering the discharge overcurrent protection, thereby reducing the risk of triggering the discharge overcurrent protection while maintaining high discharge efficiency.

[0144] See also Figure 4 , Figure 4 This is a flow chart of a method for parallel charging multiple battery packs in some embodiments of the present application. The main battery pack BMS performs the following steps:

[0145] Step S410: the battery device starts discharging and requests the total discharge current to be an initial value linit.

[0146] Step S420: obtaining a current difference value set, and defining a minimum value in the current difference value set as a first current value, wherein the current difference value set includes a current difference between a discharge overcurrent threshold and an actual discharge current of each battery pack.

[0147] After S420 , four branches are executed in parallel. The four branches include: an ascending stage in S430 , a first descending stage in S440 , a second descending stage in S450 , and a third descending stage in S460 .

[0148] S430 includes S431: in response to the first current value being greater than or equal to a first current threshold, requesting that the total discharge current of the plurality of battery packs remain unchanged, or requesting that the total discharge current of the plurality of battery packs increase at a first rate V1. The first current threshold is a positive number.

[0149] S440 includes S441, which includes: in response to the first current value being between a second current threshold and a third current threshold, requesting a reduction in the total discharge current of the plurality of battery packs at a second rate V2, wherein the second current threshold is greater than or equal to zero, and the third current threshold is greater than the second current threshold and less than or equal to the first current threshold.

[0150] S450 includes S451, S451: in response to the first current value being between a fourth current threshold and a fifth current threshold, requesting to reduce the total discharge current of the plurality of battery packs at a third rate V3, wherein the fifth current threshold is less than or equal to zero, and the fourth current threshold is less than the fifth current threshold.

[0151] S460 includes S461 , S461 : in response to the first current value being less than a sixth current threshold, requesting to reduce the total discharge current of the plurality of battery packs at a fourth rate V4 , wherein the sixth current threshold is less than or equal to the fourth current threshold.

[0152] For branch S430, in step S471, if the total discharge current is equal to the product of the median value of the allowable discharge current of each battery pack and the number of battery packs, step S472 is executed: stop increasing the total discharge current of the multiple battery packs. Then, the process returns to step S420.

[0153] For branch S440, in step S473, if the total discharge current is equal to the first target current value, the process returns to step S420. The first target current value is the product of the minimum first discharge current value of each battery pack in the plurality of battery packs and the number of battery packs. The first discharge current value of a battery pack is the product of the allowable discharge current of the battery pack and a first coefficient, where 0 < first coefficient < 1.

[0154] For branch S450, in step S474, if the total discharge current is equal to the second target current value, the process returns to step S420. The second target current value is the product of the minimum of the second discharge current values of each of the multiple battery packs and the number of battery packs. The second discharge current value of each battery pack is the product of the allowable discharge current of the battery pack and a second coefficient, where 0 < second coefficient < 1, and the second coefficient is less than the first coefficient.

[0155] For branch S460, in step S475, if the total discharge current is equal to the third target current value, the process returns to step S420. The third target current value is the product of the minimum of the third discharge current values of each of the multiple battery packs and the number of battery packs. The third discharge current value of a battery pack is the product of the allowable discharge current of the battery pack and a third coefficient, where 0 < the third coefficient < 1, and the third coefficient is less than the second coefficient.

[0156] In other words, in this embodiment, the main battery pack BMS monitors the trigger conditions of four phases in real time: the rising phase (S430), the first falling phase (S440), the second falling phase (S450), and the third falling phase (S460). If any of these conditions are met, it requests adjustment of the total discharge current using the adjustment strategy for the corresponding phase. This dynamic adjustment of the total discharge current improves the discharge efficiency and performance of the battery equipment.

[0157] In some specific embodiments, the electrical equipment including the battery pack is a vehicle (such as an electric motorcycle). When the vehicle is just started, the total discharge current requested by the battery pack is the initial value linit, which may meet one of the above trigger conditions; when the vehicle is moving, the vehicle needs to suddenly accelerate or the vehicle needs to change power to go uphill, a larger current is required, which may meet one of the above trigger conditions.

[0158] See also Figure 5 , Figure 5 This is a flow chart of a method for parallel charging of multiple battery packs in some embodiments of the present application. The main battery pack BMS performs the following steps S510 to S530:

[0159] Step S510 : determining the number of current difference values in the current difference value set and defining it as a first number.

[0160] Step S520: Calculate the number of current differences greater than or equal to the first current threshold and define it as a second number.

[0161] Step S530: Calculate the ratio of the second quantity to the first quantity and define it as a first ratio.

[0162] Step S540 : In response to the first ratio being greater than or equal to a first percentage, controlling the total discharge current of the plurality of battery packs to remain unchanged, or controlling the total discharge current of the plurality of battery packs to increase, 80%≤first percentage≤100%.

[0163] The first current threshold represents the current threshold for monitoring inefficient discharge, and the first current threshold is a positive number. It is understood that those skilled in the art may set the first current threshold based on the actual conditions of the battery device, and this application does not specifically limit this. If the current difference is greater than or equal to the first current threshold, it indicates that the corresponding battery pack is discharging at a smaller current than its own discharge overcurrent threshold, resulting in lower discharge efficiency.

[0164] The first percentage is the threshold for the proportion of battery packs with low-efficiency discharge. If the first ratio is greater than or equal to the first percentage, it indicates that the proportion of battery packs with low-efficiency discharge has reached a certain percentage, and a large number of battery packs have low discharge efficiency. Therefore, a request is made to increase the total discharge current at a first rate to improve discharge efficiency. In other words, if a first percentage of battery packs with low discharge efficiency are detected, a request is made to increase the total discharge current of the multiple battery packs at the first rate, so that the discharge current of each battery pack increases smoothly, which is beneficial to improving discharge efficiency.

[0165] It is understandable that if the first percentage is small, that is, a small number of battery packs with low discharge efficiency are detected, increasing the total discharge current can easily cause the discharge current of a certain battery pack to be greater than or equal to the discharge overcurrent threshold, resulting in over-discharge and overcurrent protection. In some embodiments, 80% ≤ first percentage ≤ 100%. That is, when the number of battery packs with low charging efficiency detected reaches [80%, 100%] of the total number of battery packs, a request to increase the total discharge current is made to help reduce the over-discharge phenomenon caused by the increase in the total discharge current causing the discharge current of a certain battery pack to be greater than or equal to the discharge overcurrent threshold. In some embodiments, 90% ≤ first percentage ≤ 100%. In this embodiment, the first percentage is more cautious, which helps to reduce over-discharge and overcurrent protection, allowing multiple battery packs to discharge at a higher discharge efficiency.

[0166] In some embodiments, the specific implementation of controlling the total discharge current of the plurality of battery packs to increase in step S540 includes the following steps: controlling the total discharge current of the plurality of battery packs to increase at a first rate.

[0167] The first rate is the rate of increase of the total discharge current, i.e., the total discharge current increases at the first rate. When the first ratio is detected to be greater than or equal to the first percentage, the total discharge current increases at the first rate. Compared to requesting the total discharge current to jump directly to a large current value, requesting the total discharge current to increase at the first rate reduces the risk of over-discharge and overcurrent protection, facilitates a smooth increase in the total discharge current, reduces the impact on electrical equipment, improves user experience, and improves the discharge efficiency of the battery pack.

[0168] For example, when the battery device starts discharging, the main battery pack BMS determines the total charging current I as the initial value linit, that is, I = linit. As the discharge progresses, if the number of battery packs with lower discharge efficiency detected at time t1 reaches a first percentage, a request is made to increase the total discharge current of the multiple battery packs at a first rate. That is, the total discharge current can be expressed by the following formula: I' = I + V1 × Δt. In some embodiments, Δt = t-t1, where t is the current time and t1 is the time when the number of battery packs with lower discharge efficiency detected reaches the first percentage.

[0169] In some embodiments, to prevent over-discharge caused by excessive total discharge current, a condition is set to stop increasing the total discharge current. For example, the main battery pack BMS calculates the product of the median allowable discharge current of each battery pack and the number of battery packs. In response to the total discharge current increasing to equal this product, the total discharge current is stopped.

[0170] As can be seen from the above, the total discharge current increases at a first rate from the time it starts to increase until it stops increasing. In some embodiments, the first rate can be variable or constant during the period of increase in the total discharge current. It is understood that if the first rate is too high, overdischarge and overcurrent protection may occur in the later stages of the total discharge current increase.

[0171] In some embodiments, to reduce the risk of overcurrent protection during the later stages of the increase, after the total discharge current increases at a first rate for a period of time, a request is made to reduce the first rate, thereby gradually slowing the increase in the total discharge current. This allows the discharge current of each battery pack to increase smoothly, helping to reduce overdischarge and overcurrent protection, and improving discharge efficiency and effectiveness.

[0172] In some embodiments, the minimum value in the current difference value set and the first rate are positively correlated. For example, the minimum value in the current difference value set and the first rate are positively correlated as follows: V1 = k × ΔI_min × N. This part has been described in the above embodiment and will not be repeated here.

[0173] In some embodiments, as Figure 6As shown, the parallel control method further includes the following steps S610 to S630:

[0174] Step S610 : Calculate the number of current differences between the second current threshold and the third current threshold and define it as a third number.

[0175] Step S620: Calculate the ratio of the third quantity to the first quantity and define it as a second ratio.

[0176] Step S630 : In response to the second ratio being greater than or equal to a second percentage, controlling the total discharge current of the plurality of battery packs to decrease, where 25%≤the second percentage≤100%.

[0177] The second current threshold is greater than or equal to zero, and the third current threshold is greater than the second current threshold and less than or equal to the first current threshold.

[0178] In this embodiment, if the current difference is a positive number, greater than or equal to the second current threshold, and less than the third current threshold, it indicates that the corresponding battery pack is discharging at a current less than but close to the discharge overcurrent threshold, and is likely to trigger discharge overcurrent protection. If a second percentage of battery packs are detected as being likely to trigger discharge overcurrent protection, the total discharge current of the multiple battery packs is controlled to decrease, thereby reducing the risk of the battery packs triggering discharge overcurrent protection and mitigating the reduction in discharge efficiency caused by the triggering of discharge overcurrent protection.

[0179] In some embodiments, 25% ≤ the second percentage ≤ 100%. That is, when the number of battery packs with a tendency to trigger discharge overcurrent protection reaches the range of [25%, 100%], controlling the total discharge current of the multiple battery packs to decrease can effectively reduce the risk of triggering discharge overcurrent protection while maintaining a relatively high discharge efficiency. In some embodiments, 50% ≤ the second percentage ≤ 100%. That is, when the number of battery packs with a tendency to trigger discharge overcurrent protection reaches [50%, 100%] of the total number of battery packs, controlling the total discharge current of the multiple battery packs to decrease can effectively reduce the risk of triggering discharge overcurrent protection while maintaining a relatively high discharge efficiency.

[0180] In some embodiments, the specific implementation process of controlling the total discharge current of multiple battery packs to decrease in step S630 includes the following steps: controlling the total discharge current of multiple battery packs to decrease at a second rate until the total discharge current value of the multiple battery packs reaches a first target current value.

[0181] The second rate is the rate at which the total discharge current decreases, meaning the total discharge current decreases at the second rate. When the second ratio is detected to be greater than or equal to the second percentage, the total discharge current decreases at the second rate. Compared to requesting the total discharge current to jump directly to a smaller current value, requesting the total discharge current to decrease at the second rate reduces the risk of overcurrent and smoothly reduces the total discharge current, ensuring discharge efficiency. Furthermore, stopping the decrease after reaching the first target current value prevents an excessive decrease in discharge efficiency, thereby maintaining a certain level of discharge efficiency.

[0182] Exemplarily, when the main battery pack detects at time t2 that the second ratio is greater than or equal to the second percentage, the total discharge current I is obtained, and a request is made to reduce the total discharge current of the multiple battery packs at the second rate. That is, the total discharge current can be expressed using the following formula: I″ = I - V2 × Δt, where I is the total discharge current before the second rate is reduced, V2 is the second rate, Δt is the time it takes to reduce the total discharge current, and I″ is the total discharge current after the second rate is reduced. In some embodiments, Δt = t - t2, where t is the current time and t2 is the time when the second ratio is detected to be greater than or equal to the second percentage.

[0183] In some embodiments, to prevent low discharge efficiency in the later stages of the total discharge current reduction, a request to reduce the second rate is made in response to the reduction in the total discharge current. In some embodiments, after the total discharge current has been decreasing at the second rate for a period of time, the request to reduce the second rate is made, so that the reduction in the total discharge current gradually slows. In other embodiments, the second rate is reduced simultaneously when the total discharge current begins to decrease. This allows the discharge current of each battery pack to decrease smoothly, helping to reduce the risk of overcurrent while maintaining high discharge efficiency.

[0184] In some embodiments, the second rate is negatively correlated with the minimum value in the current difference set. In this embodiment, a positive minimum value in the current difference set indicates that the actual discharge current of the corresponding battery pack is closest to the discharge overcurrent threshold, and that the battery pack is at the greatest risk of triggering discharge overcurrent protection. Therefore, by using the battery pack with the greatest risk of triggering discharge overcurrent protection as a benchmark, determining a second rate that is negatively correlated with its current difference can reasonably reduce the total discharge current, balancing the risk of triggering overcurrent protection with maintaining high discharge efficiency.

[0185] In some embodiments, the first target current value is defined as the product of the minimum value of the first discharge current values of each battery pack in a plurality of battery packs and the number of battery packs; the first discharge current value of the battery pack is defined as the product of the allowable discharge current of the battery pack and a first coefficient, 0<first coefficient<1.

[0186] Since the first coefficient is in the interval (0, 1), the first discharge current value of the battery pack is less than the allowable discharge current of the battery pack, and the first target current value is less than the sum of the allowable discharge currents of each battery pack. Therefore, when the total discharge current is reduced to the first target current value, the risk of discharge overcurrent protection can be effectively reduced.

[0187] In some embodiments, the first coefficient is positively correlated with the minimum value in the current difference set. In this embodiment, a positive minimum value in the current difference set indicates that the actual discharge current of the corresponding battery pack is closest to the discharge overcurrent threshold, and that the battery pack is at the greatest risk of triggering discharge overcurrent protection. Therefore, based on the battery pack with the greatest risk of triggering discharge overcurrent protection, the first coefficient is determined to be positively correlated with the minimum value in the current difference set. This helps reduce the risk of triggering discharge overcurrent protection while maintaining high discharge efficiency.

[0188] In some embodiments, as Figure 7 As shown, the parallel control method further includes the following steps S710 to S730:

[0189] Step S710 : Calculate the number of current differences between the fourth current threshold and the fifth current threshold and define it as a fourth number.

[0190] Step S720: Calculate the ratio of the fourth quantity to the first quantity and define it as a third ratio.

[0191] Step S730 : In response to the third ratio being greater than or equal to a third percentage, controlling the total discharge current of the plurality of battery packs to decrease, where 25%≤the third percentage≤100%.

[0192] If the fifth current threshold is less than or equal to zero, the fourth current threshold is less than the fifth current threshold, and the first current value is within the negative interval [fourth current threshold, fifth current threshold), this indicates that the corresponding battery pack is discharging at a current greater than the discharge overcurrent threshold and is prone to triggering discharge overcurrent protection. If a third percentage of battery packs are detected as being prone to triggering discharge overcurrent protection, the total discharge current of the multiple battery packs is controlled to decrease, thereby reducing the risk of triggering discharge overcurrent protection and mitigating the overall discharge efficiency reduction caused by the triggering of discharge overcurrent protection.

[0193] In addition, when 25% ≤ the third percentage ≤ 100%, that is, when the number of battery packs with a tendency to trigger discharge overcurrent protection reaches [25% to 100%] of the total number of battery packs, the total discharge current of the multiple battery packs is controlled to decrease to reduce the risk of triggering discharge overcurrent protection while maintaining a relatively high discharge efficiency. In some embodiments, 50% ≤ the third percentage ≤ 100%. That is, when the number of battery packs with a risk of triggering discharge overcurrent protection reaches [50% to 100%] of the total number of battery packs, the total discharge current of the multiple battery packs is controlled to decrease, which can effectively reduce the risk of triggering discharge overcurrent protection while maintaining a relatively high discharge efficiency.

[0194] In some embodiments, the specific implementation process of controlling the total discharge current of multiple battery packs to decrease in step S730 includes the following steps: controlling the total discharge current of multiple battery packs to decrease at a third rate until the total discharge current value of the multiple battery packs reaches a second target current value.

[0195] The third rate represents the rate at which the total discharge current decreases, meaning the total discharge current decreases at the third rate. When the third ratio is detected to be greater than or equal to the third percentage, the total discharge current decreases at the third rate. Compared to requesting the total discharge current to jump directly to a smaller current value, requesting the total discharge current to decrease at the third rate reduces the risk of overcurrent and ensures discharge efficiency. Furthermore, stopping the decrease after reaching the second target current value prevents an excessive decrease in discharge efficiency, thereby maintaining a certain discharge efficiency and providing appropriate power to the electrical equipment.

[0196] Exemplarily, when the main battery pack detects at time t3 that the third ratio is greater than or equal to the third percentage, the total discharge current I is obtained, and a request is made to reduce the total discharge current of the multiple battery packs at a third rate. That is, the total discharge current can be expressed using the following formula: I'' = I - V3 × Δt, where I is the total discharge current before being reduced at the third rate, V3 is the third rate, Δt is the time it takes to reduce the total discharge current, and I'' is the total discharge current after being reduced at the third rate. In some embodiments, Δt = t - t3, where t is the current time and t3 is the time at which the third ratio is detected to be greater than or equal to the third percentage.

[0197] In some embodiments, the third rate is greater than the second rate, relative to Figure 6 The decreasing phase shown reduces the total discharge current more quickly, thereby causing the actual discharge current of multiple battery packs to drop rapidly, which is beneficial to reducing safety risks such as thermal runaway of the battery pack.

[0198] In some embodiments, to prevent low discharge efficiency in the later stages of a reduction, a request is made to reduce the third rate in response to a decrease in the total discharge current. That is, after the total discharge current has decreased at the third rate for a period of time, the request is made to reduce the third rate so that the decrease in the total discharge current gradually slows. This allows the discharge current of each battery pack to decrease smoothly, helping to reduce overcurrent risks while maintaining high discharge efficiency.

[0199] In some embodiments, the third rate is negatively correlated with the minimum value in the current difference set. In this embodiment, a negative minimum value in the current difference set indicates that the actual discharge current of the corresponding battery pack is greater than the discharge overcurrent threshold, and that the battery pack is at the greatest risk of triggering discharge overcurrent protection. Therefore, by using the battery pack with the greatest risk of triggering discharge overcurrent protection as a benchmark, determining a third rate that is negatively correlated with its current difference can reasonably reduce the total discharge current, balancing the risk of triggering overcurrent protection with maintaining high discharge efficiency.

[0200] In some embodiments, the second target current value is defined as the product of the minimum value of the second discharge current values of each battery pack in a plurality of battery packs and the number of battery packs; the second discharge current value of the battery pack is defined as the product of the allowable discharge current of the battery pack and a second coefficient, 0<second coefficient<1, and the second coefficient<first coefficient.

[0201] Since the second coefficient is in the interval (0, 1), the second discharge current value of the battery pack is less than the allowable discharge current of the battery pack, and the second target current value is less than the sum of the allowable discharge currents of each battery pack. Therefore, when the total discharge current is reduced to the second target current value, the risk of discharge overcurrent protection can be effectively reduced.

[0202] In some embodiments, the second coefficient is positively correlated with the minimum value in the current difference set. In this embodiment, a negative minimum value in the current difference set indicates that the actual discharge current of the corresponding battery pack is greater than the discharge overcurrent threshold, and that the battery pack is at the greatest risk of triggering discharge overcurrent protection. Therefore, based on the battery pack with the greatest risk of triggering discharge overcurrent protection, the second coefficient is determined to be positively correlated with its battery difference. This second coefficient helps reduce the risk of triggering discharge overcurrent protection while maintaining high discharge efficiency.

[0203] In some embodiments, as Figure 8 As shown, the parallel control method further includes the following steps S810 to S830:

[0204] Step S810 : Calculate the number of current differences that are less than or equal to the sixth current threshold and define it as a fifth number.

[0205] Step S820: Calculate the ratio of the fifth quantity to the first quantity and define it as a fourth ratio.

[0206] Step S830 : In response to the fourth ratio being greater than or equal to a fourth percentage, controlling the total discharge current of the plurality of battery packs to decrease, where 25%≤the fourth percentage≤100%.

[0207] If the current difference is less than or equal to the negative sixth current threshold, and the sixth current threshold is less than or equal to the fourth current threshold, this indicates that the corresponding battery pack is discharging at a current that significantly exceeds the discharge overcurrent threshold, and the risk of triggering discharge overcurrent protection is high. When the number of battery packs monitored reaches the fourth percentage, it is confirmed that the risk of triggering discharge overcurrent protection is high, and the total discharge current of the multiple battery packs is controlled to decrease, thereby reducing the risk of triggering discharge overcurrent protection and reducing the phenomenon of reduced discharge efficiency caused by the triggering of discharge overcurrent protection.

[0208] In some embodiments, 25% ≤ the fourth percentage ≤ 100%. That is, when the number of battery packs with a high risk of discharge overcurrent protection reaching [25% to 100%] of the total number of battery packs is monitored, the total discharge current of the multiple battery packs is controlled to be reduced, which can effectively reduce the risk of discharge overcurrent protection while maintaining a relatively high discharge efficiency. In some embodiments, 50% ≤ the fourth percentage ≤ 100%. That is, when the number of battery packs with a high risk of discharge overcurrent protection reaching [50% to 100%] of the total number of battery packs is monitored, the total discharge current of the multiple battery packs is controlled to be reduced, which can effectively reduce the risk of discharge overcurrent protection while maintaining a relatively high discharge efficiency.

[0209] In some embodiments, the specific implementation process of controlling the total discharge current of multiple battery packs to decrease in step S830 includes the following steps: controlling the total discharge current of multiple battery packs to decrease at a fourth rate until the total discharge current value of the multiple battery packs reaches a third target current value.

[0210] The fourth rate is the rate at which the total discharge current decreases, meaning the total discharge current decreases at the fourth rate. When the fourth ratio is detected to be greater than or equal to the fourth percentage, the total discharge current decreases at the fourth rate. Compared to requesting the total discharge current to jump directly to a smaller current value, requesting the total discharge current to decrease at the fourth rate reduces the risk of overcurrent and ensures discharge efficiency. Furthermore, the current decrease stops after reaching the third target current value, preventing an excessive decrease in discharge efficiency and thus maintaining a certain level of discharge efficiency.

[0211] Exemplarily, when the master battery pack detects at time t4 that the fourth ratio is greater than or equal to the fourth percentage, the total discharge current I is obtained, and a request is made to reduce the total discharge current of the multiple battery packs at the fourth rate. That is, the total discharge current can be expressed using the following formula: I″=I-V4×Δt, where I is the total discharge current before being reduced at the fourth rate, V4 is the third rate, Δt is the time it takes to reduce the total discharge current, and I″” is the total discharge current after being reduced at the fourth rate. In some embodiments, Δt=t-t4, where t is the current time and t4 is the time at which the fourth ratio is detected to be greater than or equal to the fourth percentage.

[0212] In some embodiments, the fourth rate is greater than the third rate, relative to Figure 7 The decreasing phase shown reduces the total discharge current more quickly, thereby causing the actual discharge current of multiple battery packs to drop rapidly, which is beneficial to reducing the risk of safety tendencies such as thermal runaway of the battery pack.

[0213] In some embodiments, to prevent low discharge efficiency in the later stages of a discharge current reduction, a request is made to reduce the fourth rate in response to a decrease in the total discharge current. That is, after the total discharge current has decreased at the fourth rate for a period of time, the request is made to reduce the fourth rate so that the decrease in the total discharge current gradually slows. This allows the discharge current of each battery pack to decrease smoothly, helping to reduce overcurrent risks while maintaining high discharge efficiency.

[0214] In some embodiments, the fourth rate is negatively correlated with the minimum value in the current difference set. In this embodiment, a negative minimum value in the current difference set indicates that the actual discharge current of the corresponding battery pack is greater than the discharge overcurrent threshold, and that the battery pack is at the greatest risk of triggering discharge overcurrent protection. Therefore, by using the battery pack with the greatest risk of triggering discharge overcurrent protection as a benchmark, determining a fourth rate that is negatively correlated with its current difference can reasonably reduce the total discharge current, balancing the risk of triggering overcurrent protection with maintaining high discharge efficiency.

[0215] In some embodiments, the third target current value is defined as the product of the minimum value of the third discharge current values of each battery pack in a plurality of battery packs and the number of battery packs; the third discharge current value of the battery pack is defined as the product of the allowable discharge current of the battery pack and a third coefficient, 0<third coefficient<1, and the third coefficient<second coefficient.

[0216] Since the third coefficient is in the interval (0, 1), the third discharge current value of the battery pack is less than the allowable discharge current of the battery pack, and the third target current value is less than the sum of the allowable discharge currents of each battery pack. Therefore, when the total discharge current is reduced to the third target current value, the risk of discharge overcurrent protection can be effectively reduced.

[0217] In some embodiments, the third coefficient is positively correlated with the minimum value in the current difference set. In this embodiment, a negative minimum value in the current difference set indicates that the actual discharge current of the corresponding battery pack is greater than the discharge overcurrent threshold, and that the battery pack is at the greatest risk of triggering the discharge overcurrent protection. Therefore, the third coefficient is determined to be positively correlated with the current difference of the battery pack with the greatest risk of triggering the discharge overcurrent protection, thereby reducing the risk of triggering the discharge overcurrent protection while maintaining high discharge efficiency.

[0218] In the above embodiment, the second and third current thresholds are set to establish a first reduction phase for the total discharge current; the fourth and fifth current thresholds are set to establish a second reduction phase for the total discharge current; and the sixth current threshold is set to establish a third reduction phase for the total discharge current. The main battery pack BMS simultaneously monitors whether the trigger conditions for each of these three phases are met. If the trigger conditions for the first reduction phase are met, the program for reducing the total discharge current at a second rate in the first reduction phase is initiated; if the trigger conditions for the second reduction phase are met, the program for reducing the total discharge current at a third rate in the second reduction phase is initiated; and if the trigger conditions for the third reduction phase are met, the program for reducing the total discharge current at a fourth rate in the third reduction phase is initiated. The trigger conditions for the first reduction phase include: the second ratio is greater than or equal to the second percentage; the trigger conditions for the second reduction phase are: the third ratio is greater than or equal to the third percentage; and the trigger conditions for the third reduction phase are: the fourth ratio is greater than or equal to the fourth percentage. This achieves a three-stage request to reduce the total discharge current, each corresponding to a different rate and current threshold, effectively balancing charging efficiency and overcurrent risk.

[0219] See also Figure 9 , Figure 9 This is a flow chart of a method for parallel charging multiple battery packs in some embodiments of the present application. The main battery pack BMS performs the following steps:

[0220] Step S910: the battery device starts discharging and requests the total discharge current to be an initial value linit.

[0221] Step S920: obtaining a current difference value set, wherein the current difference value set includes a current difference value between a discharge overcurrent threshold value and an actual discharge current of each battery pack, and the number of current differences in the current difference value set is a first number.

[0222] After S920 , four branches are executed in parallel. The four branches include: an ascending stage at S930 , a first descending stage at S940 , a second descending stage at S950 , and a third descending stage at S960 .

[0223] S930 includes S931 and S932. S931: Calculate a second number of current differences greater than or equal to a first current threshold, and a first ratio of the second number to the first number. S932: In response to the first ratio being greater than or equal to a first percentage, request that the total discharge current of the plurality of battery packs remain unchanged, or request that the total discharge current of the plurality of battery packs increase at a first rate V1. The first current threshold is a positive number.

[0224] S940 includes S941 and S942. S941 calculates a third quantity whose current difference is between a second current threshold and a third current threshold, and a second ratio of the third quantity to the first quantity. S942 requests that the total discharge current of the plurality of battery packs be reduced at a second rate V2 in response to the second ratio being greater than or equal to a second percentage. The second current threshold is greater than or equal to zero, and the third current threshold is greater than the second current threshold and less than or equal to the first current threshold.

[0225] S950 includes S951 and S952. S951 calculates a fourth quantity whose current difference is between a fourth current threshold and a fifth current threshold, and a third ratio of the fourth quantity to the first quantity. S952 requests, in response to the third ratio being greater than or equal to a third percentage, to reduce the total discharge current of the plurality of battery packs at a third rate V3. The fifth current threshold is less than or equal to zero, and the fourth current threshold is less than the fifth current threshold.

[0226] S960 includes S961 and S962. S961: calculating a fifth number whose current difference is less than or equal to a sixth current threshold, and a fourth ratio of the fifth number to the first number; and S962: in response to the fourth ratio being greater than or equal to a fourth percentage, requesting a reduction in the total discharge current of the plurality of battery packs at a fourth rate V4. The sixth current threshold is less than or equal to the fourth current threshold.

[0227] For branch S930, in step S971, if the total discharge current is equal to the product of the median value of the allowable discharge current of each battery pack and the number of battery packs, step S972 is executed: stop increasing the total discharge current of the multiple battery packs. Then, the process returns to step S920.

[0228] For branch S940, in step S973, if the total discharge current is equal to the first target current value, the process returns to step S920. The first target current value is the product of the minimum first discharge current value of each battery pack in the plurality of battery packs and the number of battery packs. The first discharge current value of a battery pack is the product of the allowable discharge current of the battery pack and a first coefficient, where 0 < first coefficient < 1.

[0229] For branch S950, in step S974, if the total discharge current is equal to the second target current value, the process returns to step S920. The second target current value is the product of the minimum of the second discharge current values of each of the multiple battery packs and the number of battery packs. The second discharge current value of each battery pack is the product of the allowable discharge current of the battery pack and a second coefficient, where 0 < second coefficient < 1, and the second coefficient is less than the first coefficient.

[0230] For branch S960, in step S975, if the total discharge current is equal to the third target current value, the process returns to step S920. The third target current value is the product of the minimum of the third discharge current values of each of the multiple battery packs and the number of battery packs. The third discharge current value of a battery pack is the product of the allowable discharge current of the battery pack and a third coefficient, where 0 < the third coefficient < 1, and the third coefficient is less than the second coefficient.

[0231] In other words, in this embodiment, the main battery pack BMS monitors the rising phase (S930), the first falling phase (S940), the second falling phase (S950), and the third falling phase (S960) in real time or at intervals. If the trigger conditions of any of these phases are met, it requests adjustment of the total discharge current using the adjustment strategy for the corresponding phase. This dynamic adjustment of the total discharge current improves the discharge efficiency and performance of the battery device.

[0232] Some embodiments of the present application also provide a battery pack, including the electronic device in any of the above embodiments.

[0233] Some embodiments of the present application further provide an electrical device, comprising the electronic device in any one of the above embodiments.

[0234] The electrical devices of the present application are not particularly limited. In some embodiments, the electrical devices may include battery energy storage systems, electric motorcycles, electric bicycles, power tools, sweeping robots, automatic guided vehicles (AGVs), uninterruptible power supplies (UPSs), etc.

[0235] The above disclosure is only a preferred embodiment of the present application, and certainly cannot be used to limit the scope of rights of the present application. Therefore, equivalent changes made according to the claims of the present application are still within the scope covered by the present application.

Claims

1. A method for discharging multiple battery packs in parallel, characterized in that: include: Obtain the current difference between the discharge overcurrent threshold and the actual discharge current of each battery pack to obtain a current difference value set; determining a first current value, the first current value being defined as a minimum value in the set of current difference values; In response to the first current value being greater than or equal to a first current threshold, controlling the total discharge current of the plurality of battery packs to remain unchanged, or controlling the total discharge current of the plurality of battery packs to increase; or, Determining the number of current difference values in the current difference value set and defining the number as a first number; Calculating the number of current differences greater than or equal to the first current threshold and defining the number as a second number; calculating a ratio of the second quantity to the first quantity and defining the ratio as a first ratio; In response to the first ratio being greater than or equal to a first percentage, controlling the total discharge current of the plurality of battery packs to remain unchanged, or controlling the total discharge current of the plurality of battery packs to increase, where 80% ≤ the first percentage ≤ 100%; The first current threshold is a positive number, and the total discharge current is the sum of the currents output by the multiple battery packs.

2. The method according to claim 1, characterized in that The controlling the total discharge current of the plurality of battery packs to increase includes controlling the total discharge current of the plurality of battery packs to increase at a first rate.

3. The method according to claim 2, characterized in that After controlling the total discharge current of the plurality of battery packs to increase at a first rate for a period of time, controlling the first rate to decrease; In response to the total discharge current increasing to a product of a median value of the allowable discharge currents of the battery packs and the number of the battery packs, the total discharge current is stopped from increasing.

4. The method according to claim 2 or 3, characterized in that The first rate is positively correlated with a minimum value in the set of current difference values.

5. The method according to any one of claims 1 to 4, characterized in that 90%≤the first percentage≤100%.

6. The method according to any one of claims 1 to 5, characterized in that The method comprises: In response to the first current value being between a second current threshold and a third current threshold, controlling the total discharge current of the plurality of battery packs to decrease; or, calculating a number of current differences between the second current threshold and the third current threshold, and defining the number as a third number; calculating a ratio of the third quantity to the first quantity and defining the ratio as a second ratio; In response to the second ratio being greater than or equal to a second percentage, controlling the total discharge current of the plurality of battery packs to decrease, where 25%≤the second percentage≤100%; The second current threshold is greater than or equal to zero, and the third current threshold is greater than the second current threshold and less than or equal to the first current threshold.

7. The method according to claim 6, characterized in that The controlling the total discharge current of the plurality of battery packs to decrease includes: controlling the total discharge current of the plurality of battery packs to decrease at a second rate until the total discharge current value of the plurality of battery packs reaches a first target current value.

8. The method according to claim 7, characterized in that defining the first target current value as a product of a minimum value among the first discharge current values of each battery pack in the plurality of battery packs and the number of the battery packs; The first discharge current value of the battery pack is defined as the product of the allowable discharge current of the battery pack and a first coefficient, where 0<the first coefficient<1.

9. The method according to claim 8, characterized in that The first coefficient is positively correlated with a minimum value in the current difference value set.

10. The method according to any one of claims 7 to 9, characterized in that The second rate is negatively correlated with a minimum value in the set of current difference values.

11. The method according to any one of claims 6 to 10, characterized in that 50%≤the second percentage≤100%.

12. The method according to any one of claims 1 to 11, characterized in that The method comprises: In response to the first current value being between a fourth current threshold and a fifth current threshold, controlling the total discharge current of the plurality of battery packs to decrease; or, Calculating the number of current differences between the fourth current threshold and the fifth current threshold and defining the number as a fourth number, calculating a ratio of the fourth quantity to the first quantity and defining the ratio as a third ratio; In response to the third ratio being greater than or equal to a third percentage, controlling the total discharge current of the plurality of battery packs to decrease, where 25%≤the third percentage≤100%; The fifth current threshold is less than or equal to zero, and the fourth current threshold is less than the fifth current threshold.

13. The method according to claim 12, characterized in that The controlling the total discharge current of the plurality of battery packs to decrease includes: controlling the total discharge current of the plurality of battery packs to decrease at a third rate until the total discharge current value of the plurality of battery packs reaches a second target current value.

14. The method according to claim 13, characterized in that defining the second target current value as a product of a minimum value among the second discharge current values of each battery pack in the plurality of battery packs and the number of the battery packs; The second discharge current value of the battery pack is defined as the product of the allowable discharge current of the battery pack and a second coefficient, where 0<the second coefficient<1.

15. The method according to claim 14, characterized in that The second coefficient is positively correlated with a minimum value in the current difference value set.

16. The method according to any one of claims 13 to 15, characterized in that The third rate is negatively correlated with a minimum value in the set of current difference values.

17. The method according to any one of claims 12 to 16, characterized in that 50%≤the third percentage≤100%.

18. The method according to any one of claims 12 to 17, characterized in that The method comprises: In response to the first current value being less than a sixth current threshold, controlling the total discharge current of the plurality of battery packs to decrease; or, Calculating the number of current differences less than or equal to a sixth current threshold and defining the number as a fifth number; calculating a ratio of the fifth quantity to the first quantity and defining the ratio as a fourth ratio; In response to the fourth ratio being greater than or equal to a fourth percentage, controlling the total discharge current of the plurality of battery packs to decrease, where 25%≤the fourth percentage≤100%; The sixth current threshold is less than or equal to the fourth current threshold.

19. The method according to claim 18, characterized in that The controlling the total discharge current of the plurality of battery packs to decrease includes: controlling the total discharge current of the plurality of battery packs to decrease at a fourth rate until the total discharge current value of the plurality of battery packs reaches a third target current value.

20. The method according to claim 19, characterized in that defining the third target current value as a product of a minimum value among the third discharge current values of each battery pack in the plurality of battery packs and the first number; The third discharge current value of the battery pack is defined as the product of the allowable discharge current of the battery pack and a third coefficient, where 0<the third coefficient<1.

21. The method according to claim 20, characterized in that The third coefficient is positively correlated with a minimum value in the current difference value set.

22. The method according to any one of claims 19 to 21, characterized in that The fourth rate is negatively correlated with a minimum value in the set of current difference values.

23. The method according to any one of claims 19 to 22, characterized in that 50%≤the fourth percentage≤100%.

24. An electronic device, characterized in that: include: a communication unit, configured to transmit the current difference value set; A control unit is communicatively connected to the communication unit, and the control unit is configured to execute the parallel discharge method for multiple battery packs as described in any one of claims 1 to 23.

25. A battery pack, characterized in that: Comprising an electronic device as claimed in claim 24.

26. An electrical device, characterized in that: Comprising an electronic device as claimed in claim 24.

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