Battery balancing control method, device and power battery

Abstract

The present invention relates to the field of battery balancing technology, and in particular to a battery balancing control method, device, and power battery, comprising: obtaining a first state of charge (SOC) of each battery pack; charging for a set period t1, obtaining a second SOC of each battery pack, determining a first variation trend of the voltage of each battery pack over time, and determining the maximum voltage of the battery pack and the corresponding time point; passively balancing the battery packs during charging period t2; obtaining a third SOC of each battery pack at the end of charging period t2; charging for a set period t3, obtaining a fourth SOC of each battery pack, determining a second variation trend of the voltage of each battery pack over time, and determining the maximum voltage difference of the battery pack and the corresponding time point; and actively balancing the battery packs during charging period t4 based on the maximum voltage difference and the corresponding time point. The present invention allocates active and passive balancing to different stages of the charging process, making active balancing easier to perform and reducing the consumption of passive balancing.

Description

Technical Field

[0001] The present invention relates to the technical field of battery balancing, and in particular to a battery balancing control method, device, and power battery. Background Art

[0002] Power batteries are batteries that power tools, typically electric vehicles, electric trains, and electric bicycles. Power batteries require high output power. To facilitate manufacturing and power management, they are typically constructed from multiple lithium-ion battery packs connected in series or parallel.

[0003] Due to differences in manufacturing or operating conditions during use, the state of charge of lithium battery packs can become increasingly variable over time. This is primarily reflected in inconsistent external supply voltages, causing some packs to charge quickly while others take longer to do so. This inconsistency can compromise power battery safety and make overcharging and over-discharging more likely to occur.

[0004] Existing technologies offer a variety of methods for balancing battery pack voltages, primarily classified as active balancing and passive balancing. Active balancing relies on energy transfer between battery packs in different states, while passive balancing achieves balancing by using the power of battery packs with higher power consumption.

[0005] The existing technology usually adjusts the battery voltage through the above-mentioned active balancing or passive balancing method in the second half of charging or after charging is completed. This method does not pay attention to the optimal time point for the balancing operation, often resulting in insufficient voltage difference for active balancing, and at the same time wastes the power of passive balancing. Summary of the Invention

[0006] Based on this, it is necessary to provide a battery balancing control method, device and power battery to address the above problems.

[0007] The embodiment of the present invention is implemented as follows: a battery balancing control method, the battery balancing control method comprising:

[0008] Step S100, starting battery charging and obtaining a first state of charge of each battery pack;

[0009] Step S200 , charging for a set period of time t1, obtaining a second state of charge of each battery pack, determining a first variation trend of the voltage of each battery pack over time based on the first state of charge and the second state of charge, and determining a maximum voltage of the battery pack and a corresponding time point based on the first variation trend of the voltage of each battery pack over time;

[0010] Step S300 , during charging period t2 , passively balancing the battery pack according to the determined highest voltage and the corresponding time point so that the generated heat preheats the battery pack;

[0011] Step S400, obtaining a third state of charge of each battery pack at the end of charging period t2;

[0012] Step S500: Charging for a set period of time t3, obtaining a fourth state of charge of each battery pack, determining a second variation trend of the voltage of each battery pack over time based on the third and fourth states of charge, and determining a maximum voltage difference of the battery pack and the corresponding time point based on the second variation trend of the voltage of each battery pack over time;

[0013] Step S600, during charging period t4, the battery pack is actively balanced according to the maximum voltage difference and the corresponding time point;

[0014] Among them, t1+t2+t3+t4=T, T is the total charging time.

[0015] In one embodiment, the present invention provides a battery balancing control device, the battery balancing control device comprising:

[0016] a first acquisition module, configured to start battery charging and acquire a first state of charge of each battery pack;

[0017] a first charging module configured to charge for a set period of time t1, obtain a second state of charge of each battery pack, determine a first variation trend of the voltage of each battery pack over time based on the first state of charge and the second state of charge, and determine a maximum voltage of the battery pack and a corresponding time point based on the first variation trend of the voltage of each battery pack over time;

[0018] The second charging module is configured to perform passive balancing on the battery pack according to the determined highest voltage and the corresponding time point during the charging period t2 so that the generated heat can preheat the battery pack;

[0019] A second acquisition module is used to obtain a third state of charge of each battery pack at the end of the charging period t2;

[0020] a third charging module, configured to charge for a set period of time t3, obtain a fourth state of charge of each battery pack, determine a second variation trend of the voltage of each battery pack over time based on the third state of charge and the fourth state of charge, and determine a maximum voltage difference of the battery pack and a corresponding time point based on the second variation trend of the voltage of each battery pack over time;

[0021] The fourth charging module is used to actively balance the battery pack according to the maximum voltage difference and the corresponding time point during the charging period t4;

[0022] Among them, t1+t2+t3+t4=T, T is the total charging time.

[0023] In one embodiment, the present invention provides a power battery, comprising:

[0024] A power battery body, the power battery body comprising a plurality of battery pack components, each battery pack being equipped with an active balancing circuit and a passive balancing circuit; and

[0025] A control module is connected to each battery pack and is used to execute the battery balancing control method according to the present invention.

[0026] The battery balancing control method provided by this invention allocates active and passive balancing to different charging stages. It utilizes the increased voltage differential between battery packs during charging to promote passive balancing. Later in the charging process, active balancing is used to reduce the voltage differential between battery packs, thereby minimizing the voltage differential between individual packs and achieving more balanced voltage across the entire power battery. Based on basic active and passive balancing circuits, this invention requires minimal hardware modifications to existing technologies, making it easy to integrate with existing power batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A flowchart of a battery balancing control method provided by an embodiment;

[0028] Figure 2 A structural block diagram of a battery balancing control device provided in one embodiment;

[0029] Figure 3 A structural block diagram of a power battery provided in one embodiment;

[0030] Figure 4 FIG. 4 is a block diagram of the internal structure of a control module in one embodiment. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0032] It will be understood that the terms "first," "second," etc. used in the present invention may be used herein to describe various elements, but unless otherwise specified, these elements are not limited by these terms. These terms are only used to distinguish a first element from another element.

[0033] like Figure 1 As shown, in one embodiment, a battery balancing control method is proposed, which may specifically include the following steps:

[0034] Step S100, starting battery charging and obtaining a first state of charge of each battery pack;

[0035] Step S200 , charging for a set period of time t1, obtaining a second state of charge of each battery pack, determining a first variation trend of the voltage of each battery pack over time based on the first state of charge and the second state of charge, and determining a maximum voltage of the battery pack and a corresponding time point based on the first variation trend of the voltage of each battery pack over time;

[0036] Step S300 , during charging period t2 , passively balancing the battery pack according to the determined highest voltage and the corresponding time point so that the generated heat preheats the battery pack;

[0037] Step S400, obtaining a third state of charge of each battery pack at the end of charging period t2;

[0038] Step S500: Charging for a set period of time t3, obtaining a fourth state of charge of each battery pack, determining a second variation trend of the voltage of each battery pack over time based on the third and fourth states of charge, and determining a maximum voltage difference of the battery pack and the corresponding time point based on the second variation trend of the voltage of each battery pack over time;

[0039] Step S600, during charging period t4, the battery pack is actively balanced according to the maximum voltage difference and the corresponding time point;

[0040] Among them, t1+t2+t3+t4=T, T is the total charging time.

[0041] In this embodiment, the charging process is divided into four stages. The first stage lasts for t1, which is approximately 0.05T to 0.15T. During this time, each battery pack is normally charged. At the end of t1, a second state of charge (SOC) is obtained for each battery pack. In the present invention, it is understood that the state of charge (SOC) is the ratio of the remaining capacity of a battery after a period of use or long-term storage to its fully charged capacity. It is usually expressed as a percentage and has a value range of 0 to 1. When SOC = 0, the battery is fully discharged, and when SOC = 1, the battery is fully charged. In the present invention, the state of charge and the charge are essentially the same, differing only in that the state of charge is relative, while the charge is absolute. The SOC of each battery pack can be detected by the corresponding detection circuit of each battery pack. The detection and estimation of the SOC are related to the prior art and will not be further described in the present embodiment.

[0042] In this embodiment, the temporal variation trend of the voltage of each battery pack can be obtained according to the first state of charge and the second state of charge, thereby obtaining the time point at which the maximum voltage of the battery pack occurs.

[0043] In this embodiment, during time period t2, passive balancing is used to force the energy from the battery pack with the fastest voltage increase through the resistor, generating heat to preheat the battery pack. As the temperature increases, energy is more easily transferred to the battery pack, reducing internal resistance losses during charging. In this embodiment, t2 = 0.2T - 0.3T.

[0044] In this embodiment, after the passive balancing process ends, the state of charge of each battery pack changes. Charging is then performed for a period of time, t3, to reestablish the state of charge of each battery pack. The third and fourth states of charge are then used to determine the temporal trend of each battery pack's voltage, thereby determining the time point at which the maximum voltage difference between the battery packs occurs. In this embodiment, t3 can be equal to t1.

[0045] In this embodiment, during the time period t4, active balancing is used to transfer the charge from the high-voltage battery pack to the low-voltage battery pack. This process consumes less power but requires a higher voltage difference. In this embodiment, t4 = 0.3-0.5T.

[0046] As an optional embodiment of the present invention, determining a first variation trend of the voltage of each battery pack over time based on the first state of charge and the second state of charge includes:

[0047] Establish a first coordinate system with time as the horizontal axis and electric quantity as the vertical axis;

[0048] Marking a point corresponding to the first state of charge and a point corresponding to the second state of charge of each battery pack in the first coordinate system;

[0049] Determine a first charge variation line of the battery pack based on a point corresponding to the first state of charge and a point corresponding to the second state of charge of each battery pack;

[0050] Obtain a corresponding relationship table between battery pack power and voltage, and establish a second coordinate system with time as the horizontal axis and voltage as the vertical axis;

[0051] A first variation curve of the voltage of each battery pack over time is generated on the second coordinate system based on the first power variation line of each battery pack and the obtained corresponding relationship table of power and voltage.

[0052] In this embodiment, during the constant current charging process, the charge change of the battery pack can be considered to be linear, so the first charge change line of each battery pack can be determined by the point of the first state of charge and the point of the second state of charge. Here, it refers to the charge state change line of each battery pack. In this embodiment, a straight line is used to represent the charge state change trend of each battery pack.

[0053] In this embodiment, for lithium batteries, the charge level affects the output voltage. The relationship between the two is related to the characteristics of the battery pack itself. As the charge level decreases, the output voltage of the battery pack stabilizes at a specific value. For each battery pack, the relationship between charge level and voltage varies little over a certain period of time and can be considered relatively stable. Therefore, after obtaining a table of the battery pack charge-voltage relationship, the battery pack voltage at each point in time can be calculated based on the battery pack charge level.

[0054] As an optional embodiment of the present invention, determining the maximum voltage of the battery pack and the corresponding time point based on the first change trend of the voltage of each battery pack over time includes:

[0055] In the second coordinate system, determine the battery pack with the highest voltage at any time;

[0056] The time axis is segmented so that the battery pack with the highest voltage remains unchanged within the same time period, but the battery pack with the highest voltage in different time periods is different;

[0057] Determine the time point at which the battery pack with the highest voltage reaches the maximum voltage in each time period.

[0058] In this embodiment, the voltage of each battery pack varies with the charge level, and the battery pack with the highest voltage may vary in different time periods. The present invention divides the time periods into sections to identify the battery pack with the highest voltage in each time period. It should be noted that within any time period, if the battery pack identified as having the highest voltage has already been identified as having the highest voltage in another time period, this battery pack is ignored for the current time period. In other words, the battery pack with the highest voltage in each time period is determined sequentially, without duplication. After determining the battery pack with the highest voltage in each time period, the time point at which the battery pack reaches its highest voltage can be determined within the corresponding time period.

[0059] As an optional embodiment of the present invention, the passive balancing of the battery pack according to the determined highest voltage so that the generated heat preheats the battery pack includes:

[0060] In each time period, when the battery pack with the highest voltage reaches the highest voltage, the passive balancing circuit of the battery pack is started, so that the power of the battery pack generates heat through the fixed resistor to preheat the adjacent battery packs.

[0061] In this embodiment, passive balancing involves individually applying voltage to a designated resistor within each battery pack, causing the resistor to generate heat. The resistor, sandwiched between the battery packs, uses this heat to heat the adjacent battery packs, thereby reducing the internal resistance of the battery packs. The amount of heat generated can be controlled by selecting the resistor's value. Furthermore, when the voltage of the battery pack with the highest voltage is no longer the highest, power to the resistor can be stopped, thereby reducing the voltage of the faster-charging battery pack by pulling it down. Optionally, the battery pack temperature can be monitored during this process to control the heating temperature within an appropriate range.

[0062] As an optional embodiment of the present invention, determining a second variation trend of the voltage of each battery pack over time based on the third state of charge and the fourth state of charge includes:

[0063] Establish a third coordinate system with time as the horizontal axis and electric quantity as the vertical axis;

[0064] Marking a point corresponding to the third state of charge and a point corresponding to the fourth state of charge of each battery pack in the third coordinate system;

[0065] Determine a second charge variation line of the battery pack based on a point corresponding to the third state of charge and a point corresponding to the fourth state of charge of each battery pack;

[0066] Obtain a corresponding relationship table between battery pack power and voltage, and establish a fourth coordinate system with time as the horizontal axis and voltage as the vertical axis;

[0067] A second variation curve of the voltage of each battery pack over time is generated on the fourth coordinate system based on the second power variation line of each battery pack and the obtained corresponding relationship table between power and voltage.

[0068] In this embodiment, the method and process of generating the second change curve may refer to the process of generating the first change curve, and this embodiment will not be repeated here.

[0069] As an optional embodiment of the present invention, determining the maximum voltage difference of the battery pack and the corresponding time point based on the second variation trend of the voltage of each battery pack over time includes:

[0070] In the fourth coordinate system, determine the battery pack with the highest voltage and the battery pack with the lowest voltage at any time;

[0071] The time axis is segmented so that the battery pack with the highest voltage and the battery pack with the lowest voltage remain unchanged within the same time period, and the battery pack with the highest voltage and the battery pack with the lowest voltage are different in different time periods;

[0072] Determine the maximum voltage difference between the battery pack with the highest voltage and the battery pack with the lowest voltage in each time period and the corresponding time point.

[0073] In this embodiment, unlike the previous embodiment, which determines the maximum voltage of each battery pack, this embodiment determines the voltage differential between the battery pack with the highest voltage and the battery pack with the lowest voltage within each time period, and determines the time point when the voltage differential is maximum. Similarly, for any time period, the battery pack with the highest voltage and the battery pack with the lowest voltage cannot overlap with the battery pack with the highest voltage or the battery pack with the lowest voltage in any previous time period. Within each time period, the battery pack with the highest voltage and the battery pack with the lowest voltage are actively balanced as a group, and the battery packs participating in active balancing are different in each time period.

[0074] As an optional embodiment of the present invention, the active balancing of the battery pack according to the maximum voltage difference and the corresponding time point includes:

[0075] In each time period, when the voltage difference between the battery pack with the highest voltage and the battery pack with the lowest voltage reaches the maximum value, the active balancing circuit of the battery pack with the highest voltage is started to transfer the power of the battery pack with the highest voltage to the battery pack with the lowest voltage.

[0076] In this embodiment, active balancing transfers energy from a battery pack with a higher charge to a battery pack with a lower charge. This process primarily depends on the voltage difference between the two battery packs. The present invention performs this step during t4, leveraging the naturally occurring voltage difference during charging as the driving force for active balancing. Unlike conventional techniques, the present invention performs this step during charging, identifying the maximum voltage difference and facilitating active balancing.

[0077] In this embodiment, as a further optimization solution, steps S400-S600 are repeatedly executed within the t4 time period, and the maximum voltage difference and the corresponding time point are repeatedly determined each time active balancing is performed. In this way, the t4 charging time period can be fully utilized to fully balance each battery pack to solve the problem of the pressure difference expanding again after one balancing.

[0078] like Figure 2 As shown, an embodiment of the present invention further provides a battery balancing control device, the battery balancing control device comprising:

[0079] a first acquisition module, configured to start battery charging and acquire a first state of charge of each battery pack;

[0080] a first charging module configured to charge for a set period of time t1, obtain a second state of charge of each battery pack, determine a first variation trend of the voltage of each battery pack over time based on the first state of charge and the second state of charge, and determine a maximum voltage of the battery pack and a corresponding time point based on the first variation trend of the voltage of each battery pack over time;

[0081] The second charging module is configured to perform passive balancing on the battery pack according to the determined highest voltage and the corresponding time point during the charging period t2 so that the generated heat can preheat the battery pack;

[0082] A second acquisition module is used to obtain a third state of charge of each battery pack at the end of the charging period t2;

[0083] a third charging module, configured to charge for a set period of time t3, obtain a fourth state of charge of each battery pack, determine a second variation trend of the voltage of each battery pack over time based on the third state of charge and the fourth state of charge, and determine a maximum voltage difference of the battery pack and a corresponding time point based on the second variation trend of the voltage of each battery pack over time;

[0084] The fourth charging module is used to actively balance the battery pack according to the maximum voltage difference and the corresponding time point during the charging period t4;

[0085] Among them, t1+t2+t3+t4=T, T is the total charging time.

[0086] In this embodiment, each module of the battery balancing control device is a modularization of the battery balancing control method provided by the present invention. For the explanation of each module, reference may be made to the contents of the corresponding method steps of the present invention, which will not be repeated in this embodiment.

[0087] like Figure 3 As shown, an embodiment of the present invention further provides a power battery, the power battery comprising:

[0088] A power battery body, the power battery body comprising a plurality of battery pack components, each battery pack being equipped with an active balancing circuit and a passive balancing circuit; and

[0089] A control module is connected to each battery pack and is used to execute the battery balancing control method according to any one or more embodiments of the present invention.

[0090] In this embodiment, the structure of the power battery body can refer to the structure of the existing power battery, and the present invention does not involve changes to the structure of the battery pack itself of the power battery; in this embodiment, each battery pack of the power battery body is configured with an active balancing circuit and a passive balancing circuit. The existing technology provides many balancing circuits that can be directly used, and the embodiment of the present invention will not be repeated.

[0091] The power battery provided by this invention distributes active and passive balancing to different charging stages. During charging, the increased voltage differential between battery packs is utilized to promote passive balancing. Later in the charging process, active balancing is used to reduce the voltage differential between battery packs, thereby minimizing the voltage differential between individual packs and achieving more balanced voltage across the entire power battery. Based on basic active and passive balancing circuits, this invention requires minimal hardware modifications to existing technologies, making it easy to integrate with existing power batteries.

[0092] Figure 4 FIG. 1 shows an internal structure diagram of a control module in an embodiment. Figure 4 As shown, the control module includes a processor, memory, and input device connected via a system bus. The memory includes a non-volatile storage medium and internal memory. The non-volatile storage medium of the control module stores an operating system and may also store a computer program. When executed by the processor, the computer program enables the processor to implement the battery balancing control method provided in an embodiment of the present invention. The internal memory may also store a computer program. When executed by the processor, the computer program enables the processor to implement the battery balancing control method provided in an embodiment of the present invention.

[0093] Those skilled in the art will understand that Figure 4 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present invention, and does not constitute a limitation on the control module to which the solution of the present invention is applied. The specific control module may include more or fewer components than shown in the figure, or combine certain components, or have a different component arrangement.

[0094] In one embodiment, the battery balancing control device provided by the embodiment of the present invention can be implemented in the form of a computer program. The computer program can be used in the following manner: Figure 4 The control module is operated on the control module shown. The memory of the control module can store various program modules that constitute the battery balancing control device, such as, Figure 2 The computer program composed of the first acquisition module, the first charging module, the second charging module, the second acquisition module, the third charging module and the fourth charging module shown in the figure enables the processor to execute the steps of the battery balancing control method of each embodiment of the present invention described in this specification.

[0095] For example, Figure 4 The control module shown can be Figure 2In the illustrated cell balancing control device, the first acquisition module executes step S100; the control module may execute step S200 via the first charging module; the control module may execute step S300 via the second charging module; the control module may execute step S400 via the second acquisition module; the control module may execute step S500 via the third charging module; and the control module may execute step S600 via the fourth charging module.

[0096] In one embodiment, a control module is provided. The control module includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the following steps are implemented:

[0097] Start battery charging and obtain a first state of charge of each battery pack;

[0098] Charging for a set period of time t1, obtaining a second state of charge of each battery pack, determining a first change trend of the voltage of each battery pack over time based on the first state of charge and the second state of charge, and determining a maximum voltage of the battery pack and a corresponding time point based on the first change trend of the voltage of each battery pack over time;

[0099] During charging period t2, the battery pack is passively balanced according to the determined highest voltage and the corresponding time point so that the generated heat preheats the battery pack;

[0100] Obtaining a third state of charge of each battery pack at the end of charging period t2;

[0101] Charging for a set period of time t3, obtaining a fourth state of charge of each battery pack, determining a second variation trend of the voltage of each battery pack over time based on the third state of charge and the fourth state of charge, and determining a maximum voltage difference of the battery pack and a corresponding time point based on the second variation trend of the voltage of each battery pack over time;

[0102] During charging period t4, the battery pack is actively balanced according to the maximum voltage difference and the corresponding time point;

[0103] Among them, t1+t2+t3+t4=T, T is the total charging time.

[0104] In one embodiment, a computer-readable storage medium is provided. The computer-readable storage medium stores a computer program. When the computer program is executed by a processor, the processor performs the following steps:

[0105] Start battery charging and obtain a first state of charge of each battery pack;

[0106] Charging for a set period of time t1, obtaining a second state of charge of each battery pack, determining a first change trend of the voltage of each battery pack over time based on the first state of charge and the second state of charge, and determining a maximum voltage of the battery pack and a corresponding time point based on the first change trend of the voltage of each battery pack over time;

[0107] During charging period t2, the battery pack is passively balanced according to the determined highest voltage and the corresponding time point so that the generated heat preheats the battery pack;

[0108] Obtaining a third state of charge of each battery pack at the end of charging period t2;

[0109] Charging for a set period of time t3, obtaining a fourth state of charge of each battery pack, determining a second variation trend of the voltage of each battery pack over time based on the third state of charge and the fourth state of charge, and determining a maximum voltage difference of the battery pack and a corresponding time point based on the second variation trend of the voltage of each battery pack over time;

[0110] During charging period t4, the battery pack is actively balanced according to the maximum voltage difference and the corresponding time point;

[0111] Among them, t1+t2+t3+t4=T, T is the total charging time.

[0112] It should be understood that, although the various steps in the flow chart of each embodiment of the present invention are shown in sequence according to the indication of the arrows, these steps are not necessarily performed in sequence according to the order indicated by the arrows. Unless otherwise specified herein, the execution of these steps is not strictly limited in order, and these steps can be performed in other orders. Moreover, at least a portion of the steps in each embodiment may include a plurality of sub-steps or a plurality of stages, and these sub-steps or stages are not necessarily performed at the same time, but can be performed at different times, and the execution order of these sub-steps or stages is not necessarily performed in sequence, but can be performed in turn or alternately with at least a portion of other steps or sub-steps or stages of other steps.

[0113] Those skilled in the art will appreciate that all or part of the processes in the above-described embodiments can be implemented by instructing the relevant hardware through a computer program. The program can be stored in a non-volatile computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above-described methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided by the present invention can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0114] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0115] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A battery balancing control method, characterized in that: The battery balancing control method includes: Step S100, starting battery charging and obtaining a first state of charge of each battery pack; Step S200 , charging for a set period of time t1, obtaining a second state of charge of each battery pack, determining a first variation trend of the voltage of each battery pack over time based on the first state of charge and the second state of charge, and determining a maximum voltage of the battery pack and a corresponding time point based on the first variation trend of the voltage of each battery pack over time; Step S300 , during charging period t2 , passively balancing the battery pack according to the determined highest voltage and the corresponding time point so that the generated heat preheats the battery pack; Step S400, obtaining a third state of charge of each battery pack at the end of charging period t2; Step S500: Charging for a set period of time t3, obtaining a fourth state of charge of each battery pack, determining a second variation trend of the voltage of each battery pack over time based on the third and fourth states of charge, and determining a maximum voltage difference of the battery pack and the corresponding time point based on the second variation trend of the voltage of each battery pack over time; Step S600, during charging period t4, the battery pack is actively balanced according to the maximum voltage difference and the corresponding time point; Wherein, t1+t2+t3+t4=T, T is the total charging time, and steps S400-S600 are repeatedly executed within the time period t4; The determining of a first variation trend of the voltage of each battery pack over time based on the first state of charge and the second state of charge includes: Establish a first coordinate system with time as the horizontal axis and electric quantity as the vertical axis; Marking a point corresponding to the first state of charge and a point corresponding to the second state of charge of each battery pack in the first coordinate system; Determine a first charge variation line of the battery pack based on a point corresponding to the first state of charge and a point corresponding to the second state of charge of each battery pack; Obtain a corresponding relationship table between battery pack power and voltage, and establish a second coordinate system with time as the horizontal axis and voltage as the vertical axis; Generating a first variation curve of the voltage of each battery pack over time on a second coordinate system based on the first power variation line of each battery pack and the obtained correspondence relationship table between the power and voltage of the battery pack; The determining of a second variation trend of the voltage of each battery pack over time based on the third state of charge and the fourth state of charge includes: Establish a third coordinate system with time as the horizontal axis and electric quantity as the vertical axis; Marking a point corresponding to the third state of charge and a point corresponding to the fourth state of charge of each battery pack in the third coordinate system; Determine a second charge variation line of the battery pack based on a point corresponding to the third state of charge and a point corresponding to the fourth state of charge of each battery pack; Obtain a corresponding relationship table between battery pack power and voltage, and establish a fourth coordinate system with time as the horizontal axis and voltage as the vertical axis; A second variation curve of the voltage of each battery pack over time is generated on the fourth coordinate system based on the second power variation line of each battery pack and the obtained corresponding relationship table between the power and voltage of the battery pack.

2. The battery balancing control method according to claim 1, wherein: The determining of the maximum voltage of the battery pack and the corresponding time point based on the first variation trend of the voltage of each battery pack over time includes: In the second coordinate system, determine the battery pack with the highest voltage at any time; The time axis is segmented so that the battery pack with the highest voltage remains unchanged within the same time period, but the battery pack with the highest voltage in different time periods is different; Determine the time point at which the battery pack with the highest voltage reaches the maximum voltage in each time period.

3. The battery balancing control method according to claim 2, wherein: The passive balancing of the battery pack according to the determined highest voltage and the corresponding time point so that the generated heat preheats the battery pack includes: In each time period, when the battery pack with the highest voltage reaches the highest voltage, the passive balancing circuit of the battery pack is started, so that the power of the battery pack generates heat through the fixed resistor to preheat the adjacent battery packs.

4. The battery balancing control method according to claim 1, wherein: The determining of the maximum voltage difference of the battery pack and the corresponding time point based on the second variation trend of the voltage of each battery pack over time includes: In the fourth coordinate system, determine the battery pack with the highest voltage and the battery pack with the lowest voltage at any time; The time axis is segmented so that the battery pack with the highest voltage and the battery pack with the lowest voltage remain unchanged within the same time period, and the battery pack with the highest voltage and the battery pack with the lowest voltage are different in different time periods; Determine the maximum voltage difference between the battery pack with the highest voltage and the battery pack with the lowest voltage in each time period and the corresponding time point.

5. The battery balancing control method according to claim 4, wherein: The active balancing of the battery pack according to the maximum voltage difference and the corresponding time point includes: In each time period, when the voltage difference between the battery pack with the highest voltage and the battery pack with the lowest voltage reaches the maximum value, the active balancing circuit of the battery pack with the highest voltage is started to transfer the power of the battery pack with the highest voltage to the battery pack with the lowest voltage.

6. A battery balancing control device, characterized in that: The battery balancing control device includes: a first acquisition module, configured to start battery charging and acquire a first state of charge of each battery pack; a first charging module configured to charge for a set period of time t1, obtain a second state of charge of each battery pack, determine a first variation trend of the voltage of each battery pack over time based on the first state of charge and the second state of charge, and determine a maximum voltage of the battery pack and a corresponding time point based on the first variation trend of the voltage of each battery pack over time; The second charging module is configured to perform passive balancing on the battery pack according to the determined highest voltage and the corresponding time point during the charging period t2 so that the generated heat can preheat the battery pack; A second acquisition module is used to obtain a third state of charge of each battery pack at the end of the charging period t2; a third charging module, configured to charge for a set period of time t3, obtain a fourth state of charge of each battery pack, determine a second variation trend of the voltage of each battery pack over time based on the third state of charge and the fourth state of charge, and determine a maximum voltage difference of the battery pack and a corresponding time point based on the second variation trend of the voltage of each battery pack over time; The fourth charging module is used to actively balance the battery pack according to the maximum voltage difference and the corresponding time point during the charging period t4; Wherein, t1+t2+t3+t4=T, T is the total charging time; The determining of a first variation trend of the voltage of each battery pack over time based on the first state of charge and the second state of charge includes: Establish a first coordinate system with time as the horizontal axis and electric quantity as the vertical axis; Marking a point corresponding to the first state of charge and a point corresponding to the second state of charge of each battery pack in the first coordinate system; Determine a first charge variation line of the battery pack based on a point corresponding to the first state of charge and a point corresponding to the second state of charge of each battery pack; Obtain a corresponding relationship table between battery pack power and voltage, and establish a second coordinate system with time as the horizontal axis and voltage as the vertical axis; Generating a first variation curve of the voltage of each battery pack over time on a second coordinate system based on the first power variation line of each battery pack and the obtained correspondence relationship table between the power and voltage of the battery pack; The determining of a second variation trend of the voltage of each battery pack over time based on the third state of charge and the fourth state of charge includes: Establish a third coordinate system with time as the horizontal axis and electric quantity as the vertical axis; Marking a point corresponding to the third state of charge and a point corresponding to the fourth state of charge of each battery pack in the third coordinate system; Determine a second charge variation line of the battery pack based on a point corresponding to the third state of charge and a point corresponding to the fourth state of charge of each battery pack; Obtain a corresponding relationship table between battery pack power and voltage, and establish a fourth coordinate system with time as the horizontal axis and voltage as the vertical axis; A second variation curve of the voltage of each battery pack over time is generated on the fourth coordinate system based on the second power variation line of each battery pack and the obtained corresponding relationship table between the power and voltage of the battery pack.

7. A power battery, characterized in that: The power battery includes: A power battery body, the power battery body comprising a plurality of battery pack assemblies, each battery pack being equipped with an active balancing circuit and a passive balancing circuit; and A control module, connected to each battery pack, and configured to execute the battery balancing control method according to any one of claims 1 to 5.

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