A method for calculating the equalization time of a battery cell and a method for controlling the equalization of a battery

Abstract

The present application provides a method for calculating the equalization time of a battery cell and a method for controlling the equalization of a battery. The method for calculating the equalization time of a battery cell includes: obtaining the current data and voltage data of the battery cell in the process of charging and discharging in real time; calculating the first amount of electricity required to be equalized of the battery cell at the end of this charging according to the current data and voltage data; obtaining the current equalization current of the battery cell; calculating the first equalization time of the battery cell according to the first amount of electricity required to be equalized and the current equalization current; obtaining the previous equalization time of the battery cell during the last charging and discharging process; calculating the credibility of the battery cell according to the previous equalization time; calculating the equalization time of charging the battery cell according to the first equalization time and credibility, so that the equalization time of charging a single battery cell can be accurately calculated, and the accuracy of balancing the entire battery can be improved by balancing each battery cell in the battery separately.

Description

Technical Field

[0001] The present application relates to the field of energy storage technology, and in particular to a method for calculating the balancing time of a battery cell and a method for controlling the balancing of a battery. Background Art

[0002] In the field of energy storage, two or more cells are usually connected together to form a group of batteries, which can significantly increase the available capacity of the entire battery. In addition, the number of cells can be adjusted according to actual needs to adapt to different application scenarios and load requirements. Due to production differences, usage history, and environmental conditions of different single cells, differences in voltage and capacity may occur, that is, consistency problems of each cell, resulting in a battery barrel effect, reducing the utilization of the battery's available capacity, and resulting in low battery economy. In addition, the cycle life of the battery is much lower than the service life of its lowest single cell, which is a problem for the promotion of batteries in the field of energy storage and power.

[0003] Based on this, the battery needs to be balanced. The balancing technology is the core of the battery management system and an important method to solve the consistency problem of each battery cell in the battery. It can change the charging and discharging current or the cumulative charge and discharge power between different batteries. Continuous and effective balancing technology and correct balancing control strategy can prevent consistency differences in batteries and play an important role in the battery life indicator.

[0004] The balancing time of the battery cells is the key to balancing the battery. If the balancing time is unreasonable, not only will the differences between the battery cells fail to be resolved, but it may also cause the battery to generate a lot of heat during balancing, affecting the battery's service life.

[0005] However, in the process of implementing the embodiments of the present application, the inventors of the present application found that the current battery cannot calculate the balancing time of a single battery cell and can only provide the balancing time of the entire battery group. When the battery is balanced, the balancing of each battery cell is performed based on the balancing time of the entire battery group, which cannot match the actual needs of each battery cell and the balancing control is inaccurate. Summary of the invention

[0006] In view of the above problems, the present application provides a method for calculating the balancing time of a battery cell and a method for controlling the balancing of a battery, which overcome the above problems or at least partially solve the above problem of being unable to calculate the balancing time of a single battery cell.

[0007] According to one aspect of the present application, a method for calculating the equalization time of a battery cell is provided, which is applied to a battery, wherein the battery includes a plurality of battery cells, and the method includes: acquiring current data and voltage data of the battery cell in real time during charging and discharging; calculating a first required equalization quantity of the battery cell at a current charging cutoff time according to the current data and voltage data; acquiring the current equalization current of the battery cell; calculating a first equalization time of the battery cell according to the first required equalization quantity and the current equalization current; acquiring a previous equalization time of the battery cell during the last charging and discharging process; calculating the credibility of the battery cell according to the previous equalization time; and calculating the equalization time of charging the battery cell according to the first equalization time and the credibility.

[0008] In an optional manner, the method further includes: calculating a second required balancing power of the battery cell at the end of this discharge according to the current data and the voltage data; calculating a second balancing time of the battery cell according to the second required balancing power and the current balancing current; and calculating a balancing time for the discharge of the battery cell according to the second balancing time and the credibility.

[0009] In an optional manner, the pre-balance time includes a first pre-balance time and a second pre-balance time, the first pre-balance time corresponds to the last charging process, the second pre-balance time corresponds to the last discharging process, and the formula for calculating the credibility based on the pre-balance time is:

[0010]

[0011] Among them, the For the i the reliability of the battery cell, the m is an empirical value. For the i the first pre-balancing time of each of the cells, For the i The second pre-balancing time of each of the cells; wherein the When greater than 1, the Take 1.

[0012] In an optional manner, the pre-balancing time includes a first pre-balancing time and a second pre-balancing time, and the step of obtaining the pre-balancing time of the battery cell during the last charging and discharging process includes: obtaining the pre-current data and the pre-voltage data of the battery cell during the last charging and discharging process; calculating the first pre-balancing power required for the battery cell at the previous charging cut-off moment according to the pre-current data and the pre-voltage data; calculating the second pre-balancing power required for the battery cell at the previous discharging cut-off moment according to the pre-current data and the pre-voltage data; obtaining the pre-balancing current of the battery cell; calculating the first pre-balancing time of the battery cell according to the first pre-balancing power required and the pre-balancing current; and calculating the second pre-balancing time of the battery cell according to the second pre-balancing power required and the pre-balancing current.

[0013] In an optional manner, the formula for calculating the equalization time of charging the battery cell according to the first equalization time and the credibility is:

[0014]

[0015] Among them, the For the i The equalization time of charging the battery cells, For the i the first balancing time of each of the cells, For the i The reliability of each of the battery cells.

[0016] In an optional manner, before the step of calculating the first amount of electricity required to be balanced of the battery cell at the end of this charging process based on the current data and the voltage data, the method further includes: obtaining the charging terminal voltage of the battery cell in this charging process based on the voltage data; determining whether the charging terminal voltage is greater than a first voltage threshold; if so, entering the step of calculating the first amount of electricity required to be balanced of the battery cell at the end of this charging process based on the current data and the voltage data.

[0017] In an optional manner, the step of calculating the first amount of electricity required to be balanced of the battery cell at the current charging cut-off moment according to the current data and the voltage data includes: calculating the excess electricity of each of the battery cells from the first moment to the current charging cut-off moment according to the current data and the voltage data, to obtain multiple excess electricity, wherein the first moment is when the voltage of the battery cell reaches a first preset voltage, wherein the first preset voltage is between the discharge cut-off voltage and the charge cut-off voltage; obtaining the minimum value of the multiple excess electricity as the charging minimum value, wherein the first amount of electricity required to be balanced is the difference between the excess electricity of the battery cell and the charging minimum value.

[0018] In an optional manner, the step of obtaining the current balancing current of the battery cell includes: obtaining the current voltage of the battery cell at a current moment; obtaining the balancing resistance of the battery cell; and obtaining the balancing current of the battery cell according to the current voltage and the balancing resistance.

[0019] According to one aspect of an embodiment of the present application, a battery balancing control method is provided, which is applied to a battery, wherein the battery includes a plurality of battery cells, and the method includes: obtaining a charging balancing time of each of the battery cells respectively, wherein the charging balancing time of the battery cells is calculated using the above-mentioned battery cell balancing time calculation method; and performing balancing control on the battery according to the charging balancing time of each of the battery cells.

[0020] In an optional manner, the multiple battery cells include odd-numbered battery cells and even-numbered battery cells, and the odd-numbered battery cells and the even-numbered battery cells have the same preset balancing time. The step of performing balancing control on the battery according to the balancing time of each battery cell includes: performing balancing control on the battery according to a balancing cycle, performing balancing control on the odd-numbered battery cells according to the preset balancing time in one balancing cycle, controlling the battery to stop balancing according to an interval time, and performing balancing control on the even-numbered battery cells according to the preset balancing time; obtaining the maximum value of the balancing time of each battery cell as the balancing maximum value; calculating the number of balancing times according to the balancing maximum value and the preset balancing time; and performing balancing control on the battery according to the balancing cycle and the number of balancing times.

[0021] In an optional manner, the step of performing balancing control on the battery according to the balancing cycle includes: performing balancing control on the odd-numbered battery cells according to the preset balancing time; obtaining the heat value of the battery; comparing the heat value with a first threshold value and a second threshold value; when the heat value is greater than the first threshold value, controlling to increase the interval time, controlling the battery to stop balancing according to the increased interval time, and performing balancing control on the even-numbered battery cells according to the preset balancing time; when the heat value is less than the second threshold value, controlling to reduce the interval time, controlling the battery to stop balancing according to the reduced interval time, and performing balancing control on the even-numbered battery cells according to the preset balancing time.

[0022] According to one aspect of an embodiment of the present application, a device for calculating the equalization time of a battery cell is provided, which is applied to a battery, wherein the battery includes a plurality of the battery cells, and the device includes: a first acquisition module, used to acquire current data and voltage data of the battery cell during a current charging and discharging process; a first calculation module, used to calculate a first required equalization amount of the battery cell at a current charging cutoff moment according to the current data and voltage data; a second acquisition module, used to acquire the current equalization current of the battery cell; a second calculation module, used to calculate a first equalization time of the battery cell according to the first required equalization amount and the equalization current; a third acquisition module, used to acquire a previous equalization time of the battery cell during a previous charging and discharging process; a third calculation module, used to calculate the credibility of the battery cell according to the previous equalization time; and a fourth calculation module, used to calculate the equalization time of charging of the battery cell according to the first equalization time and the credibility.

[0023] According to one aspect of an embodiment of the present application, a battery balancing control device is provided, which is applied to a battery, wherein the battery includes a plurality of battery cells, and the device includes: an acquisition module, used to respectively acquire the balancing time of charging each of the battery cells, wherein the balancing time of charging the battery cells is calculated by the above-mentioned method for calculating the balancing time of the battery cells; and a control module, used to perform balancing control on the battery according to the balancing time of charging each of the battery cells.

[0024] According to one aspect of an embodiment of the present application, a battery is provided, comprising: at least one processor, and a memory, wherein the memory is communicatively connected to the at least one processor, the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the method as described above.

[0025] According to one aspect of an embodiment of the present application, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores a computer program. When the computer program is executed by a processor, the processor performs the steps of the above method.

[0026] The beneficial effects of the present application include: the present application provides a method for calculating the equalization time of a battery cell, which is applied to a battery, wherein the battery includes a plurality of batteries, and the method includes: obtaining the current data and voltage data of the battery cell during the current charging and discharging process; calculating the first required equalization power of the battery cell at the end time of the current charging according to the current data and voltage data; obtaining the current equalization current of the battery cell; calculating the first equalization time of the battery cell according to the first required equalization power and the equalization current; obtaining the previous equalization time of the battery cell during the last charging and discharging process; calculating the credibility of the battery cell according to the previous equalization time; calculating the equalization time of the battery cell charging according to the first equalization time and the credibility. Through this method, the equalization time of charging a single battery cell can be accurately and reliably calculated, and when the battery is balanced, each battery cell can be balanced according to the equalization time of charging each battery cell in the battery, thereby improving the accuracy of the equalization control of the entire battery, improving the efficiency of the equalization control of the battery, and thus effectively extending the service life of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0028] Figure 1 is a schematic diagram of an application environment provided by an embodiment of the present application;

[0029] Figure 2 is a schematic diagram of the hardware structure of a battery provided in an embodiment of the present application;

[0030] Figure 3 It is a flowchart of a method for calculating the equalization time of a battery cell provided in an embodiment of the present application;

[0031] Figure 4 It is a schematic diagram of a flow chart of calculating the first amount of electricity required to be balanced of a cell at the end time of this charging provided by an embodiment of the present application;

[0032] Figure 5 is a schematic diagram of the relationship between various parameters of various battery cells during the charging process provided by the embodiment of the present application;

[0033] Figure 6 is a schematic diagram of a flow chart for calculating the current balancing current of a battery cell provided in an embodiment of the present application;

[0034] Figure 7 It is a flowchart of obtaining the pre-equalization time provided by an embodiment of the present application;

[0035] Figure 8It is a flow chart of another method for calculating the balancing time of a battery cell provided in an embodiment of the present application;

[0036] Fig. 9 is a schematic diagram of the relationship between various parameters of various battery cells during the discharge process provided by the embodiment of the present application;

[0037] Fig.10 It is a flowchart of another method for calculating the balancing time of a battery cell provided in an embodiment of the present application;

[0038] Fig.11 It is a flowchart of a battery balancing control method provided in an embodiment of the present application;

[0039] Fig.12 It is a schematic diagram of a flow chart of performing battery balancing control according to a balancing cycle provided in an embodiment of the present application;

[0040] Fig.13 It is a schematic diagram of a flow chart of balancing control of batteries based on heat generation provided in an embodiment of the present application;

[0041] Fig.14 is a schematic diagram of a device for calculating the equalization time of a battery cell provided in an embodiment of the present application;

[0042] Fig.15 Schematic diagram of a battery balancing control device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. 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. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field belong to the scope of protection of this application.

[0044] In addition, the technical features involved in the embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0045] See also Figure 1 , Figure 1 1 is a schematic diagram of an application environment provided in an embodiment of the present application, and the application environment is applicable to the method for calculating the equalization time of the battery cell, the equalization control method of the battery, the device for calculating the actual capacity of the battery cell, and the equalization control device of the battery. The application environment is a battery 100, and the battery 100 includes a plurality of battery cells 10. In some embodiments, the plurality of battery cells 10 are connected in series.

[0046] The battery 100 may be a lithium-ion battery, which mainly includes consumer batteries, power batteries and energy storage batteries. Among them, the consumer battery usually requires small size, light weight, high energy density and long cycle life, and is widely used in personal electronic devices such as mobile phones, laptops, tablet computers, digital cameras and portable music players. Among them, the power battery is mainly used in transportation tools such as new energy vehicles, electric bicycles, electric trains, etc., to provide the instantaneous high power output required by the vehicle to support operations such as acceleration and climbing. Among them, the energy storage battery is mostly used as a battery energy storage system for renewable energy such as solar energy, wind power, and hydropower, as well as grid peak and frequency regulation, backup power supply, microgrid and other occasions, mainly for long-term storage and stable release of energy. No matter which type of battery, there is a charging and discharging process. Due to the inconsistency of each battery cell in the battery, the power in each battery cell is different, and it is necessary to balance the control of each battery cell to solve the problem of consistency of each battery cell. When the balance control of each battery cell in the battery is performed, it is necessary to obtain the balance time of a single battery cell, so as to further balance it according to the balance time of each battery cell.

[0047] It is understandable that, in some embodiments, the battery further includes a battery management system (not shown), which is one of the core subsystems of the battery and is responsible for monitoring the operating status of the battery cell 10 to ensure safe and reliable operation of the battery cell 10. BMS can monitor and collect the state parameters of the battery cell 10 and / or the battery 100 in real time (including but not limited to the voltage, current, temperature of the battery cell 10, the insulation resistance of the battery 100, etc.), and perform necessary analysis and calculation on the relevant state parameters to obtain more state evaluation parameters, and realize effective control of the battery 100 according to a specific protection control strategy to ensure the safe and reliable operation of the entire battery 100. At the same time, BMS can exchange information with other external devices (PCS, EMS, fire protection system, etc.) through its own communication interface and analog / digital input interface to form a linkage control to ensure the safe, reliable and efficient operation of the battery 100.

[0048] In order to solve the technical problem in the prior art that the balancing time of a single battery cell cannot be calculated, an embodiment of the present application provides a method for calculating the balancing time of a battery cell.

[0049] Embodiment 1

[0050] Before describing in detail the calculation method of the equalization time of the battery cell, the hardware structure of the battery 100 provided in the embodiment of the present application is described.

[0051] See also Figure 2 , Figure 21 is a schematic diagram of the hardware structure of a battery provided in an embodiment of the present application. The battery can execute the calculation method of the equalization time of the battery cell and the equalization control method of the battery. The battery 100 includes at least one processor 11 and a memory 12 ( Figure 2 A bus connection and a processor are used as an example). A person skilled in the art can understand that Figure 2 The structure shown is for illustration only and does not limit the structure of the above-mentioned battery. Figure 2 More or fewer components as shown, or with Figure 2 Different configurations shown.

[0052] The processor 11 is used to provide computing and control capabilities to control the battery 100 to perform corresponding tasks, for example, to control the battery 100 to perform any method provided in the following application embodiments.

[0053] It can be understood that the processor 11 can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components.

[0054] The memory 12, as a non-transient computer-readable storage medium, can be used to store non-transient software programs, non-transient computer executable programs and modules, such as program instructions / modules corresponding to the various calculation methods in the embodiments of the present application. The processor 11 can implement the various calculation methods in any of the following method embodiments by running the non-transient software programs, instructions and modules stored in the memory 12. The memory 12 may include a high-speed random access memory and may also include a non-transient memory, such as at least one disk storage device, a flash memory device, or other non-transient solid-state storage devices. In some embodiments, the memory 12 may also include a memory remotely arranged relative to the processor, and these remote memories may be connected to the processor via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network and a combination thereof.

[0055] Embodiment 2

[0056] The embodiment of the present application also provides a non-volatile computer-readable storage medium, wherein the non-volatile computer-readable storage medium stores computer-executable instructions, and the computer-executable instructions are used by a battery to execute each calculation method in any of the following method embodiments.

[0057] An embodiment of the present application provides a computer program product, including a computing program stored on a non-volatile computer-readable storage medium, wherein the computer program includes program instructions, and when the program instructions are executed by a computer, the computer executes each computing method in any of the following method embodiments.

[0058] Through the description of the above implementation methods, ordinary technicians in this field can clearly understand that each implementation method can be implemented by means of software plus a general hardware platform, and of course it can also be implemented by hardware. Ordinary technicians in this field can understand that all or part of the processes in the above-mentioned embodiment method can be completed by instructing related hardware through a computer program, and the program can be stored in a computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, the storage medium can be a disk, an optical disk, a read-only memory (ROM) or a random access memory (RAM), etc.

[0059] Embodiment 3

[0060] The following is a discussion of a method for calculating the balancing time of a battery cell provided in an embodiment of the present application, wherein the balancing time of a battery cell is used to measure the duration of balancing control of the battery cell, thereby eliminating or reducing inconsistencies between battery cells, improving the performance of the entire battery, and extending the battery life.

[0061] It is worth noting that the inconsistency difference of the battery cells at the charging end is large, which has a great impact on the performance of the battery. The inconsistency difference of the battery cells at the discharging end is small, which has a small impact on the performance of the battery. Therefore, the embodiment of the present application mainly calculates the balancing time of the battery cell charging, and uses it as the balancing time for the battery cell. The balancing time of the battery cell charging is used to perform balancing control on the battery cell. The embodiment of the present application calculates the balancing time of the battery cell discharging as a supplement, and uses the balancing time of the battery cell discharging to assist in balancing control of the battery cell.

[0062] See also Figure 3 , Figure 3 : is a flow chart of a method for calculating the equalization time of a battery cell provided in an embodiment of the present application, the method comprising the following steps:

[0063] Step S10, acquiring current data and voltage data of the battery cell during charging and discharging in real time.

[0064] It is understandable that when the battery includes a battery management system, the battery management system can obtain the current information and voltage information of each battery cell during the charging process and the discharging process respectively. Specifically, the battery management system is provided with an AFE (Analog Front End), which is a series of circuits used to process analog signals in an electronic system. In a battery management system (BMS), the AFE is used to measure battery voltage, current and other parameters with high precision, and convert these analog signals into digital signals for further processing and analysis.

[0065] It is worth noting that, since the cells in the battery are not consistent, the voltage data of the cells are not consistent during charging / discharging, that is, the voltages of the cells cannot be guaranteed to be consistent at the same time during charging / discharging.

[0066] The step S1 includes the step of obtaining the current data and the voltage data of the battery cell during the current charging and discharging process. The current charging and discharging process refers to the charging process of the battery being fully charged for the last time before the current moment (the moment of calculating the balancing time), and the discharging process of the battery being discharged for the last time before the current moment (the moment of calculating the balancing time).

[0067] The step S1 also includes the step of obtaining the current data and voltage data of the battery cell during the last charging and discharging process, wherein the last charging and discharging process refers to the charging process of the battery being fully charged before the last moment (the moment when the balancing time was last calculated), and the discharging process of the battery being discharged to empty before the last moment (the moment when the balancing time was last calculated).

[0068] The current data during the charging process includes: all current data from the start time of charging to the end time of charging, including the current-time curve during charging. The voltage data during the charging process includes: all voltage data from the start time of charging to the end time of charging, including the voltage-time curve during charging.

[0069] The charging start time is the time when the battery starts to be charged, that is, the charging start time of each battery cell is the same. The charging end time is the time when the battery is stopped from being charged, that is, the charging end time of each battery cell is the same. In some embodiments, when the voltage of one of the battery cells reaches the charging end voltage, the charging end time is reached. At this time, even if the voltage of other battery cells has not reached the charging end voltage, the charging of the battery is stopped.

[0070] The current data during the discharge process includes: all current data from the start time of discharge to the end time of discharge, including the current-time curve during discharge. The voltage data during the discharge process includes: all voltage data from the start time of discharge to the end time of discharge, including the voltage-time curve during discharge.

[0071] The discharge start time is the time when the battery starts to be discharged, that is, the discharge start time of each battery cell is the same. The discharge end time is the time when the battery is stopped from being discharged, that is, the discharge end time of each battery cell is the same. In some embodiments, when the voltage of one of the battery cells reaches the discharge end voltage, the discharge end time is reached. At this time, even if the other battery cells have not reached the discharge end voltage, the discharge of the battery is stopped.

[0072] Step S20, calculating the first required balancing power of the battery cell at the end time of this charging according to the current data and the voltage data.

[0073] It can be understood that the current charging cut-off time is the charging cut-off time of the most recent charging process of the battery before the current time (the time for calculating the balancing time).

[0074] Due to the inconsistency of each of the battery cells, not all of the battery cells reach the charging cut-off voltage when the charging cut-off time is reached, that is, different battery cells may have different charges at the charging cut-off time, and the first charge to be balanced reflects the difference between the battery cell and other battery cells when the battery is stopped from being charged.

[0075] It is worth noting that, in some embodiments, see Figure 4 , Figure 4 This is a flow chart of calculating the first amount of electricity required to be balanced at the end of charging of the battery cell according to an embodiment of the present application, that is, step S20 further includes:

[0076] Step S201 , according to the current data and the voltage data, respectively calculating the excess power of each of the battery cells from the first moment to the current charging end moment, to obtain a plurality of excess powers.

[0077] The first moment is when the voltage of the battery cell reaches a first preset voltage, wherein the first preset voltage is between a discharge cut-off voltage and a charge cut-off voltage. For example, the voltage range of the battery cell is usually 1.2V-4.2V, and the first preset voltage can be set to 3.8V or 4.0V.

[0078] It can be understood that the first preset voltage is a preset value.

[0079] It is worth noting that for multiple charge and discharge cycle processes, such as the current charge and discharge process and the previous charge and discharge process, the first preset voltage can be set to the same value.

[0080] It is worth noting that, due to the inconsistency of the battery cells, the time at which the battery cells reach the first preset voltage may be different, that is, the first moment of the battery cells is different.

[0081] The excess power of the battery cell from the first moment to the end moment of this charging can be calculated according to the ampere-hour method, and the formula for the excess power is:

[0082]

[0083] Among them, the For the i The excess power of the battery cells from the first moment to the end moment of this charging, t 2 is the current charging cut-off time, t 1Cell（i） For the i the first moment of the battery cell, the I ( t ) is the current in this charging process, t For time.

[0084] It can be understood that, in some embodiments, the number of the plurality of excess electric quantities is the same as the number of the battery cells, and one battery cell corresponds to one excess electric quantity.

[0085] It can be understood that, in some embodiments, the number of the plurality of excess power is less than the number of the battery cells, that is, not every battery cell has the excess power.

[0086] Step S202, obtaining a minimum value among the plurality of excess electric quantities as a charging minimum value, wherein the first electric quantity to be balanced is a difference between the excess electric quantity of the battery cell and the charging minimum value.

[0087] After obtaining multiple excess powers, the minimum value of the multiple excess powers can be obtained by comparison and used as the minimum charging value. Then, according to the difference between the excess power of a single battery cell and the minimum charging value, the first required balancing power of the battery cell can be obtained.

[0088] To help readers understand the above excess power, the first equalization power and the minimum charging value, an example is given below. Figure 5 , Figure 5 is a schematic diagram of the relationship between various parameters of each battery cell during the charging process provided by the embodiment of the present application, that is, Figure 5 The example shows the excess power of the battery cell during the charging process, the first power required for balancing, and the minimum charging value. Figure 5 The horizontal axis represents the time of this charging process. Figure 5 The vertical axis represents the electric quantity. Figure 5 The three curves shown in FIG. 1 represent the relationship between the charge level of three different batteries and the time during the charging process. Figure 5 The excess power of the first battery cell Maximum, , the excess power of the third battery cell Minimum, that is, the third cell corresponds to the minimum charging value, which is . Figure 5 The excess power of the second cell in , the first balanced charge of the second cell is .

[0089] Step S30, obtaining the current balancing current of the battery cell.

[0090] The current balancing current is the current used when balancing the battery cells, which is determined according to the balancing resistance at the current moment (the moment of calculating the balancing time of the battery cells).

[0091] In some embodiments, see Figure 6 , Figure 6 is a schematic diagram of a process for calculating the current balancing current of a battery cell provided in an embodiment of the present application, that is, step S30 further includes:

[0092] Step S301, obtaining the current voltage of the battery cell at the current moment.

[0093] The current voltage can be obtained by the battery management system for each of the battery cells, specifically, by the AFE (Analog Front End) provided in the battery management system.

[0094] Step S302, obtaining the balancing resistance of the battery cell.

[0095] The cell balancing resistor is an external component used to achieve battery balancing in the battery management system (BMS). When a cell in the battery needs to be balanced, the BMS can dissipate part of the power in the cell in the form of heat through the balancing resistor, thereby reducing the difference between the cells. The resistance of the balancing resistor is usually in the ohm (Ω) level. The balancing resistor is a pre-set external component with a certain resistance value.

[0096] For the multiple cells in the battery, the balancing resistances are the same.

[0097] Step S303: acquiring the current balancing current of the battery cell according to the current voltage and the balancing resistance.

[0098] Whether during charging or discharging, the calculation method of the balancing current of the battery cell is the ratio of the current voltage to the balancing resistance.

[0099] During charging, the equation for the balancing current is:

[0100]

[0101] Among them, the For the i The balancing current of each of the cells during this charging, For the i the current voltage of each of the cells, the R is the balancing resistor.

[0102] During discharge, the equation for the balancing current is:

[0103]

[0104] Among them, the For the i The balancing current of each of the cells during this discharge, For the i the current voltage of each of the cells, the R is the balancing resistor.

[0105] Step S40: calculating a first balancing time of the battery cell according to the first amount of electricity to be balanced and the current balancing current.

[0106] The first balancing time is the ratio of the first amount of electricity to be balanced to the current balancing current. The calculation formula of the first balancing time is:

[0107]

[0108] Among them, the For the i the first balancing time of each of the cells, For the i the first balanced charge of the battery cells, For the i The current balancing current of each of the battery cells during charging.

[0109] Step S50, obtaining the previous equalization time of the battery cell during the last charging and discharging process.

[0110] It is worth noting that the pre-equalization time corresponds to the last charging and discharging process, and in fact the pre-equalization time is calculated based on the pre-current data and pre-voltage data in the last charging and discharging process.

[0111] The last charging and discharging process is the previous charging and discharging process before the current charging and discharging process.

[0112] It is worth noting that if the last charging and discharging process does not meet the conditions for balancing, that is, after the last charging and discharging process, the consistency of each battery cell is good, then there is no need to balance in this charging and discharging process. At this time, the balancing time corresponding to the closest charging and discharging process in the history to the current charging and discharging process is used as the pre-balancing time.

[0113] In some embodiments, the pre-balance time includes a first pre-balance time and a second pre-balance time, wherein the first pre-balance time corresponds to the last charging process, and the second pre-balance time corresponds to the last discharging process. Figure 7 , Figure 7 The present invention provides a flow chart of obtaining the pre-equalization time, that is, step S50 further includes:

[0114] Step S501, obtaining the previous current data and the previous voltage data of the battery cell during the last charging and discharging process.

[0115] Among them, the previous current data includes current-related data of the battery cell during the last charging process, and current-related data of the battery cell during the last discharging process. For details, please refer to the description of the current data in the above step S10, which will not be repeated here.

[0116] Among them, the previous voltage data includes data related to the voltage of the battery cell during the last charging process, and data related to the voltage of the battery cell during the last discharging process. For details, please refer to the description of the voltage data in the above step S10, which will not be repeated here.

[0117] Step S502: calculating a first required balancing power of the battery cell at a previous charging cut-off time according to the previous current data and the previous voltage data.

[0118] The previous charging cut-off time corresponds to the charging cut-off time of the previous charging process. For details, please refer to the description of the charging cut-off time in the above step S10, which will not be repeated here.

[0119] The first amount of electricity required to be balanced corresponds to the last charging process, and the first amount of electricity required to be balanced reflects the difference between the cell and other cells before charging the battery in the last charging process. The calculation method of the first amount of electricity required to be balanced can refer to the calculation of the first amount of electricity required to be balanced in step S20, which will not be repeated here.

[0120] Step S503, calculating the second required balancing power of the battery cell at the previous discharge cut-off time according to the previous current data and the previous voltage data.

[0121] The previous discharge cut-off time corresponds to the discharge cut-off time of the previous discharge process. For details, please refer to the description of the discharge cut-off time in the above step S10, which will not be repeated here.

[0122] The second amount of electricity required to be balanced before corresponds to the last discharge process, and the second amount of electricity required to be balanced before reflects the difference between the battery cell and other battery cells before the battery is discharged during the last discharge process.

[0123] It is worth noting that, in some embodiments, an implementation method for calculating the second pre-balancing power is: according to the previous current data and the previous voltage data, respectively calculate the previous maximum discharge capacity of each of the battery cells from the previous second moment to the previous discharge cut-off moment, and obtain multiple previous maximum discharge capacities, wherein the previous second moment is when the voltage of the battery cell reaches a second preset voltage, wherein the second preset voltage is between the discharge cut-off voltage and the first preset voltage; obtain the maximum value of the multiple multiple discharge capacities as the previous discharge maximum value, and the second pre-balancing power required is the difference between the previous discharge maximum value and the previous maximum discharge capacity of the battery cell.

[0124] For example, the voltage range of the battery cell is usually 1.2V-4.2V, and the second preset voltage can be set to 2.0V).

[0125] It can be understood that the second preset voltage is a preset value.

[0126] It is worth noting that for multiple charge and discharge cycle processes, such as the current charge and discharge process and the previous charge and discharge process, the second preset voltage can be set to the same value.

[0127] It is worth noting that, due to the inconsistency of the battery cells, the time at which the battery cells reach the second preset voltage may be different, that is, the second previous moment of each battery cell is different.

[0128] The previous maximum discharge amount of the battery cell from the previous second moment to the previous discharge cut-off moment can be calculated according to the ampere-hour method, and the formula for the previous maximum discharge amount is:

[0129]

[0130] Among them, the is the previous maximum discharge amount of the ith cell from the previous second moment to the previous discharge cut-off moment, t F3 is the front discharge cut-off time, the t F2Cell（i） is the second moment before the ith cell, I ( t ) is the current in the last discharge process, and t is the time.

[0131] It can be understood that, in some embodiments, the number of the plurality of front-maximum discharge amounts is the same as the number of the battery cells, and one battery cell corresponds to one front-maximum discharge amount.

[0132] It can be understood that, in some embodiments, the number of the plurality of front-maximum discharge capacities is less than the number of the battery cells, that is, not every battery cell has the front-maximum discharge capacity.

[0133] After obtaining multiple front-end discharge capacities, the maximum value among the multiple front-end discharge capacities can be obtained by comparison and taken as the front-end discharge maximum value. Then, according to the difference between the front-end discharge capacity of a single battery cell and the front-end discharge maximum value, the second front-end balancing capacity of the battery cell can be obtained.

[0134] Step S504, obtaining the front balancing current of the battery cell.

[0135] The previous balancing current is the balancing current determined according to the balancing resistor at the last moment (the moment when the balancing time was last calculated). The specific calculation method of the previous balancing current can refer to the calculation method of the current balancing current in step S30, which will not be repeated here.

[0136] Step S505 : calculating the first pre-balancing time of the battery cell according to the first pre-balancing power required and the pre-balancing current.

[0137] The first pre-balancing time is the ratio of the first pre-balancing power to the pre-balancing current. The specific calculation formula of the first pre-balancing time can refer to the formula for calculating the first balancing time in step S40, which will not be repeated here.

[0138] Step S506: calculating the second pre-balancing time of the battery cell according to the second pre-balancing required electric quantity and the pre-balancing current.

[0139] The second pre-balancing time is the ratio of the second pre-balancing power to be balanced to the pre-balancing current. The calculation formula of the second pre-balancing time is:

[0140]

[0141] Among them, the For the i the second pre-balancing time of each of the cells, For the i the second front balanced charge of each of the battery cells, For the i The pre-balancing current of each of the battery cells during discharge.

[0142] Step S60: calculating the reliability of the battery cell according to the pre-balancing time.

[0143] The reliability of the battery cell is actually a balancing coefficient for calculating the balancing time of the battery cell. The reliability of the battery cell is calculated based on the previous balancing time, that is, corresponding to the last charging and discharging process. By introducing the reliability of the battery cell, accurate and efficient balancing of each battery cell in the battery can be achieved.

[0144] It is worth noting that, in some embodiments, the formula for calculating the reliability of the battery cell according to the pre-balance time is:

[0145]

[0146] Among them, the For the i the reliability of the battery cell, the m is an empirical value. For the i the first pre-balancing time of each of the cells, For the i The second pre-balancing time of each of the cells;

[0147] Among them, the credibility When greater than 1, the credibility Take 1.

[0148] It is worth noting that the m is an empirical value obtained based on experience. In some embodiments, the m The value of is 2. It can be understood that m The value of can also be other values, such as 2.2, 2.5, 2.7 or 3.

[0149] Step S70: Calculate the equalization time for charging the battery cell according to the first equalization time and the credibility.

[0150] The equalization time of the battery cell charging is the product of the first equalization time and the credibility. The formula for calculating the equalization time of the battery cell charging according to the first equalization time and the credibility is:

[0151]

[0152] Among them, the For the i The equalization time of charging the battery cells, For the i the first balancing time of each of the cells, For the i The reliability of each of the battery cells.

[0153] It is worth noting that, when the credibility is greater than 1, the credibility is taken as 1, that is, the finally obtained balancing time of the battery cell charging is less than or equal to the first balancing time, that is, when the battery cell is balanced according to the balancing time of the battery cell charging, the balancing control of the battery can be achieved quickly and efficiently.

[0154] It is worth noting that, since there are large differences between the battery cells during the charging process, the battery cells may be balanced based only on the charging process of the battery cells, that is, only the equalization time of the battery cell charging is used as the equalization time of the battery cell.

[0155] In the embodiment of the present application, the calculation method of the equalization time of the battery cell includes: obtaining the current data and voltage data of the battery cell during the current charging and discharging process; calculating the first required equalization power of the battery cell at the end time of the current charging according to the current data and voltage data; obtaining the current equalization current of the battery cell; calculating the first equalization time of the battery cell according to the first required equalization power and the current equalization current; obtaining the previous equalization time of the battery cell during the last charging and discharging process; calculating the credibility of the battery cell according to the previous equalization time; calculating the equalization time of the battery cell charging according to the first equalization time and credibility. Through this method, the equalization time of charging a single battery cell can be accurately and reliably calculated. When the battery is balanced, each battery cell can be balanced according to the equalization time of charging each battery cell in the battery, so as to improve the accuracy of the equalization control of the entire battery and the efficiency of the equalization control of the battery, thereby effectively extending the service life of the battery.

[0156] Embodiment 4

[0157] The following is a discussion of another method for calculating the balancing time of a battery cell provided in an embodiment of the present application. Figure 8 , Figure 81 is a flow chart of another method for calculating the equalization time of a battery cell provided in an embodiment of the present application. In addition to the above steps S10, S20, S30, S40, S50, S60 and S70, the method for calculating the equalization time of another battery cell further includes the following steps:

[0158] Step S100, calculating the second required balancing power of the battery cell at the end time of this discharge according to the current data and the voltage data.

[0159] The current discharge cut-off time corresponds to the discharge cut-off time of the current discharge process. For details, please refer to the description of the discharge cut-off time in the above step S10, which will not be repeated here.

[0160] The second amount of electricity required to be balanced corresponds to the current discharge process, and the second amount of electricity required to be balanced reflects the difference between the battery cell and other battery cells before the battery is discharged during the current discharge process.

[0161] It is worth noting that, in some embodiments, an implementation method for calculating the second amount of electricity to be balanced is: according to the current data and the voltage data, respectively calculate the multiple discharge amounts of each of the battery cells from the second moment to the end moment of this discharge, and obtain multiple multiple discharge amounts, wherein the second moment is when the voltage of the battery cell reaches a second preset voltage, wherein the second preset voltage is between the discharge end voltage and the first preset voltage; obtain the maximum value of the multiple multiple discharge amounts as the discharge maximum value, and the second amount of electricity to be balanced is the difference between the discharge maximum value and the multiple discharge amount of the battery cell.

[0162] For example, the voltage range of the battery cell is usually 1.2V-4.2V, and the second preset voltage can be set to 2.0V).

[0163] It can be understood that the second preset voltage is a preset value.

[0164] It is worth noting that for multiple charge and discharge cycle processes, such as the current charge and discharge process and the previous charge and discharge process, the second preset voltage can be set to the same value.

[0165] It is worth noting that, due to the inconsistency of the battery cells, the time at which the battery cells reach the second preset voltage may be different, that is, the second moment of each battery cell is different.

[0166] The excess discharge amount of the battery cell from the second moment to the current discharge cut-off moment can be calculated according to the ampere-hour method, and the formula for the excess discharge amount is:

[0167]

[0168] Among them, the For the i The multiple discharge amount of the battery cells from the second moment to the end moment of the current discharge, t 3 is the current discharge cut-off time, t 2Cell（i） For the i At the second moment of each of the cells, I ( t ) is the current in this discharge process, and t is the time.

[0169] It can be understood that, in some embodiments, the number of the multiple discharge capacities is the same as the number of the battery cells, and one battery cell corresponds to one multiple discharge capacity.

[0170] It can be understood that, in some embodiments, the number of the multiple discharge capacities is less than the number of the battery cells, that is, not every battery cell has the multiple discharge capacities.

[0171] After obtaining multiple multiple discharge capacities, the maximum value among the multiple discharge capacities can be obtained by comparison and used as the discharge maximum value, and then the second required balancing capacity of the battery cell can be obtained according to the difference between the multiple discharge capacity of a single battery cell and the discharge maximum value.

[0172] To help readers understand the above-mentioned multiple discharge capacity, the second required equalization capacity and the maximum charge value, an example is given below. Fig. 9 , Fig. 9 is a schematic diagram of the relationship between various parameters of each battery cell during the discharge process provided by the embodiment of the present application, that is, Fig. 9 The example shows the maximum discharge amount, the second required equalization amount and the maximum charge value of the battery cell during the discharge process. Fig. 9 The horizontal axis represents the time of this discharge process. Fig. 9 The vertical axis represents the electric quantity. Fig. 9 The three curves shown in FIG. 1 represent the relationship between the charge and time of three different cells during the discharge process. Fig. 9 The maximum discharge capacity of the first battery cell The minimum is , the extra discharge capacity of the third cell The minimum, that is, the minimum discharge value corresponding to the third battery cell is . Fig. 9 The excess discharge capacity of the second cell in , the second balanced charge of the second cell is . Fig. 9 In is the difference between the excess discharge capacity of the second cell and the minimum discharge value, Fig. 9 In The discharge capacity difference is the difference between the maximum discharge value and the minimum discharge value.

[0173] Step S200: calculating a second balancing time of the battery cell according to the second amount of electricity to be balanced and the current balancing current.

[0174] The second balancing time is the ratio of the second amount of electricity to be balanced to the current balancing current. The calculation formula for the second balancing time is:

[0175]

[0176] Among them, the For the i the second balancing time of each of the cells, For the i the second balanced charge of each of the battery cells, For the i The current balancing current of each of the battery cells during discharge.

[0177] Step S300: Calculate the balancing time of the discharge of the battery cell according to the second balancing time and the credibility.

[0178] The balance time of the cell discharge is the product of the second balance time and the credibility. The formula for calculating the balance time of the cell discharge according to the second balance time and the credibility is:

[0179]

[0180] Among them, the For the i The equalization time of the discharge of the battery cells, For the i the second balancing time of each of the cells, For the i The reliability of each of the battery cells.

[0181] It is worth noting that, when the credibility is greater than 1, the credibility is taken as 1, that is, the finally obtained balancing time of the battery cell discharge is less than or equal to the second balancing time, that is, when the battery cell is balanced according to the balancing time of the battery cell discharge, the balancing control of the battery can be achieved quickly and efficiently.

[0182] It is worth noting that, since the differences between the battery cells are large during the charging process and small during the discharging process, the battery cells can be balanced mainly based on the charging process of the battery cells, and auxiliary balancing of the battery cells can be performed during the discharging process of the battery cells.

[0183] In an embodiment of the present application, a method for calculating the balancing time of a battery cell includes: obtaining current data and voltage data of the battery cell during the current charging and discharging process; calculating a first required balancing amount of the battery cell at the end of the current charging process based on the current data and voltage data; obtaining the current balancing current of the battery cell; calculating a first balancing time of the battery cell based on the first required balancing amount and the current balancing current; obtaining a previous balancing time of the battery cell during the last charging and discharging process; calculating the credibility of the battery cell based on the previous balancing time; calculating the balancing time of charging the battery cell based on the first balancing time and credibility; calculating a second required balancing amount of the battery cell at the end of the current discharging process based on the current data and voltage data; calculating a second balancing time of the battery cell based on the second required balancing amount and the current balancing current; calculating a balancing time of discharging the battery cell based on the second balancing time and credibility. By using this method, not only the equalization time of charging the battery cells can be accurately and reliably calculated, but also the equalization time of discharging the battery cells can be accurately and reliably calculated. When performing equalization control on the battery, each battery cell can be balanced according to the equalization time of charging each battery cell and the equalization time of discharging each battery cell in the battery, thereby further improving the accuracy of the equalization control of the entire battery, further improving the efficiency of the equalization control of the battery, and further effectively extending the service life of the battery.

[0184] Embodiment 5

[0185] The following is a discussion of another method for calculating the balancing time of a battery cell provided in an embodiment of the present application. Fig. 9 , Fig. 9 1 is a flow chart of another method for calculating the equalization time of a battery cell provided in an embodiment of the present application. In addition to the above-mentioned steps S10, S20, S30, S40, S50, S60 and S70, after step S10 and before step S20, another method for calculating the equalization time of a battery cell further includes the following steps:

[0186] Step S1-21, obtaining the charging terminal voltage of the battery cell in this charging process according to the voltage data.

[0187] The charging terminal voltage is the voltage of the battery cell when the current charging process of the battery is terminated. Since each battery cell is inconsistent, the charging terminal voltage of each battery cell is different when the current charging process of the battery is terminated.

[0188] Step S1-22, determine whether the charging terminal voltage is greater than a first voltage threshold, if so, proceed to step S20.

[0189] The first voltage threshold is actually a condition for the battery cell to be balanced. Since in the aforementioned step S20, the first amount of electricity required to be balanced of the battery cell at the end of this charging is calculated according to the first preset voltage, the first voltage threshold is actually equal to the first preset voltage.

[0190] It is worth noting that if the charging terminal voltage is less than or equal to the first voltage threshold, it is not necessary to balance the battery cells and it is not necessary to calculate the balancing time of the battery cells. For the entire battery, some of the battery cells will need to calculate the balancing time while some of the battery cells will not. In this case, the balancing time for calculating each of the battery cells in the battery is short, the battery burden is light, and the efficiency of battery balancing control can be improved.

[0191] It is worth noting that, based on Example 4, according to Example 5, after step S70 and before step S100, the method further includes: obtaining the end discharge voltage of the battery cell in this discharge process according to the voltage data; judging whether the end discharge voltage is less than a second voltage threshold, and if so, entering step S100.

[0192] The discharge terminal voltage is the voltage of the battery cell when the current discharge process of the battery is terminated. Since each battery cell is inconsistent, the discharge terminal voltage of each battery cell is different when the current discharge process of the battery is terminated.

[0193] The second voltage threshold is actually a condition for the battery cell to be balanced. Since in the aforementioned step S100, the second required equalization quantity of the battery cell at the end of this discharge is calculated according to the second preset voltage, the second voltage threshold is actually equal to the second preset voltage.

[0194] It is worth noting that if the end-of-discharge voltage is greater than or equal to the second voltage threshold, it is not necessary to balance the battery cells and it is not necessary to calculate the balancing time of the battery cells. For the entire battery, some of the battery cells will need to calculate the balancing time while some of the battery cells will not. In this case, the balancing time of each of the battery cells in the battery is short, the battery burden is light, and the efficiency of battery balancing control can be improved.

[0195] In the embodiment of the present application, the calculation method of the equalization time of the battery cell includes: obtaining the current data and voltage data of the battery cell during the current charging and discharging process; obtaining the charging terminal voltage of the battery cell during the current charging process according to the voltage data; judging whether the charging terminal voltage is greater than the first voltage threshold; if so, calculating the first required equalization power of the battery cell at the end time of the current charging according to the current data and voltage data; obtaining the current equalization current of the battery cell; calculating the first equalization time of the battery cell according to the first required equalization power and the current equalization current; obtaining the previous equalization time of the battery cell during the last charging and discharging process; calculating the credibility of the battery cell according to the previous equalization time; calculating the equalization time of the battery cell charging according to the first equalization time and the credibility. Through this method, not only can the equalization time of the battery cell charging be accurately and reliably calculated, but also the equalization time of each battery cell in the battery can be saved in the calculation, so the battery burden is light and the efficiency of the battery equalization control can be improved.

[0196] Embodiment 6

[0197] The following is a discussion of the battery balancing control method provided by the embodiment of the present application. Fig.11 , Fig.11 : is a flow chart of a battery balancing control method provided in an embodiment of the present application, the method comprising the following steps:

[0198] Step 1, respectively obtaining the equalization time of charging of each of the battery cells;

[0199] The equalization time of charging the battery cell is calculated by the above-mentioned method for calculating the equalization time of the battery cell.

[0200] Step 2: performing equalization control on the battery according to the equalization time of charging each of the battery cells.

[0201] Specifically, the balancing control of each of the battery cells in the battery may be performed respectively according to the balancing time of charging each of the battery cells.

[0202] It is understandable that other methods can be used to balance the battery. In some embodiments, the plurality of cells include odd-numbered cells and even-numbered cells, and the odd-numbered cells and even-numbered cells have the same preset balancing time. Fig.12 The step of performing equalization control on the battery according to the equalization time of charging each of the battery cells, i.e., step S2, further includes the following steps:

[0203] Step 21, performing balancing control on the battery according to a balancing cycle.

[0204] In one balancing cycle, the odd-numbered cells are balanced according to the preset balancing time, the battery is controlled to stop balancing according to the interval time, and the even-numbered cells are balanced according to the preset balancing time. According to this method, when the odd-numbered cells are balanced according to the preset balancing time, the odd-numbered cells generate heat, and the even-numbered cells do not generate heat, and when the even-numbered cells are balanced according to the preset balancing time, the even-numbered cells generate heat, and the odd-numbered cells do not generate heat, that is, the odd-numbered cells and the even-numbered cells generate heat alternately, thereby avoiding continuous balancing control of one of the cells, thereby controlling the heat generation of the cells, controlling the heat generation of the battery, and improving the safety of balancing control of the battery.

[0205] The preset balancing time is a preset value, which may be, for example, 5 seconds to 10 seconds, or other values.

[0206] It is worth noting that, in some embodiments, see Fig.13 The step of performing equalization control on the battery according to the equalization cycle includes:

[0207] Step 211 , performing balancing control on the odd-numbered battery cells according to the preset balancing time.

[0208] Step 212, obtaining the heat generated by the battery.

[0209] The heat generated by the battery can be obtained by a temperature sensor disposed in the battery, or by a temperature control circuit disposed in the battery and connected to the battery management system.

[0210] It can be understood that, in some embodiments, the heat generated by the battery is the heat generated by the entire battery, not the heat generated by odd-numbered battery cells, nor the heat generated by even-numbered battery cells.

[0211] Step 213, comparing the heating value with the first threshold and the second threshold. When the heating value is greater than the first threshold, executing step S214; when the heating value is less than the second threshold, executing step S215.

[0212] The first threshold and the second threshold are both preset values. By introducing the heat value, when the heat value is large, specifically greater than the first threshold, the interval time can be increased, thereby reducing the temperature of the battery and improving the safety of the battery; when the heat value is small, specifically less than the second threshold, the interval time can be reduced, thereby shortening the overall time of balancing control of the battery and improving the efficiency of balancing control of the battery.

[0213] By introducing the heat value, the first threshold and the second threshold, the balancing strategy can be adjusted based on the actual balancing control of the battery and the state of the entire battery. This can not only effectively control the temperature of the battery and achieve high-safety balancing control, but also effectively control the overall time of balancing control of the battery and improve efficiency.

[0214] Step 214 , controlling to increase the interval time, controlling the battery to stop balancing according to the increased interval time, and performing balancing control on the even-numbered battery cells according to the preset balancing time.

[0215] Step 215 , controlling to reduce the interval time, controlling the battery to stop balancing according to the reduced interval time, and performing balancing control on the even-numbered battery cells according to the preset balancing time.

[0216] Step 22, obtaining a maximum value of the equalization time of charging of each of the battery cells as the equalization maximum value.

[0217] The equilibrium maximum value is as follows:

[0218]

[0219] Among them, the is the equilibrium maximum value, the For the 1st to n The equalization time of charging the battery cells, wherein the n Is a positive integer.

[0220] Step 23, calculating the number of equalization times according to the equalization maximum value and the preset equalization time.

[0221] In some embodiments, the ratio of the maximum equalization value to the preset equalization time is rounded up to obtain the equalization times. The formula for obtaining the equalization times is:

[0222]

[0223] Among them, the K is the number of balancing times, is the equilibrium maximum value, the T 1 is the preset balancing time.

[0224] Step 24, performing balancing control on the battery according to the balancing period and the balancing times.

[0225] It can be understood that the number of balancing times is the number of times the battery is balanced according to the balancing cycle, that is, by performing the balancing times on each of the battery cells according to the balancing cycle, the battery can be balanced.

[0226] It is worth noting that the actual balancing time for balancing the battery is the product of the balancing period and the number of balancing times, that is, the formula for the actual balancing time for balancing the battery is:

[0227]

[0228] Among them, the T is the actual balancing time for balancing the battery. T 1 The preset balancing time for balancing the odd-numbered cells is T 2 The preset balancing time for balancing the even-numbered cells is T 3 is the interval time, the is the balancing period. T 1 Equal to the T 2 .

[0229] In the embodiment of the present application, the battery balancing control method includes respectively obtaining the balancing time of each of the battery cells, the balancing time of the battery cells being calculated by the above-mentioned calculation method of the balancing time of the battery cells; and performing balancing control on the battery according to the balancing time of each of the battery cells. Through this method, each of the battery cells in the battery can be balancingly controlled based on the balancing time of each of the battery cells, so that the accuracy of the balancing control of the battery is high, the probability of misjudgment is low, and the reliability of the balancing control of the battery is good.

[0230] Embodiment 7

[0231] The following is a discussion of the calculation device for the equalization time of the battery cell provided in the embodiment of the present application. Fig.14 , Fig.141 is a schematic diagram of a calculation device for the equalization time of a battery cell provided in an embodiment of the present application, wherein the calculation device 1 for the equalization time of a battery cell comprises a first acquisition module 11, for acquiring in real time the current data and voltage data of the battery cell during the charging and discharging process; a first calculation module 12, for calculating the first required equalization power of the battery cell at the current charging cut-off time according to the current data and the voltage data; a second acquisition module 13, for acquiring the current equalization current of the battery cell; a second calculation module 14, for calculating the first equalization time of the battery cell according to the first required equalization power and the current equalization current; a third acquisition module 15, for acquiring the previous equalization time of the battery cell during the last charging and discharging process; a third calculation module 16, for calculating the credibility of the battery cell according to the previous equalization time; and a fourth calculation module 17, for calculating the equalization time of charging the battery cell according to the first equalization time and the credibility.

[0232] In some embodiments, the first calculation module 12 includes a first calculation unit 121, which is used to calculate the excess power of each of the battery cells from the first moment to the current charging cut-off moment according to the current data and the voltage data, and obtain multiple excess powers, wherein the first moment is when the voltage of the battery cell reaches a first preset voltage, wherein the first preset voltage is between the discharge cut-off voltage and the charge cut-off voltage; a first acquisition unit 122, which is used to obtain the minimum value of the multiple excess powers as the charging minimum value, and the first required balancing power is the difference between the excess power of the battery cell and the charging minimum value.

[0233] In some embodiments, the second acquisition module 13 includes a second acquisition unit 131, which is used to acquire the current voltage of the battery cell at the current moment; a third acquisition unit 132, which is used to acquire the balancing resistance of the battery cell; and a fourth acquisition unit 133, which is used to acquire the current balancing current of the battery cell according to the current voltage and the balancing resistance.

[0234] In some embodiments, the pre-balancing time includes a first pre-balancing time and a second pre-balancing time, and the third acquisition module 15 includes a fifth acquisition unit 151, which is used to obtain the pre-current data and pre-voltage data of the battery cell during the last charging and discharging process; a second calculation unit 152, which is used to calculate the first pre-balancing power required by the battery cell at the pre-charging cut-off moment according to the pre-current data and the pre-voltage data; a third calculation unit 153, which is used to calculate the second pre-balancing power required by the battery cell at the pre-discharging cut-off moment according to the pre-current data and the pre-voltage data; a sixth acquisition unit 154, which is used to obtain the pre-balancing current of the battery cell; a fourth calculation unit 155, which is used to calculate the first pre-balancing time of the battery cell according to the first pre-balancing power required and the pre-balancing current; and a fifth calculation unit 156, which is used to calculate the second pre-balancing time of the battery cell according to the second pre-balancing power required and the pre-balancing current.

[0235] In some embodiments, the device also includes a fifth calculation module 18, which is used to calculate the second required balancing power of the battery cell at the end of this discharge according to the current data and the voltage data; a sixth calculation module 19, which is used to calculate the second balancing time of the battery cell according to the second required balancing power and the current balancing current; and a seventh calculation module 20, which is used to calculate the balancing time of the battery cell discharge according to the second balancing time and the credibility.

[0236] In some embodiments, the device also includes a fourth acquisition module 21, which is used to obtain the charging terminal voltage of the battery cell in this charging process based on the voltage data; a judgment module 22, which is used to judge whether the charging terminal voltage is greater than a first voltage threshold; if so, enter the first calculation module 12.

[0237] In the embodiment of the present application, the current data and voltage data of the battery cell during the current charging and discharging process are obtained by the first acquisition module 11; the first required equalization power of the battery cell at the current charging cut-off time is calculated by the first calculation module 12 according to the current data and voltage data; the current equalization current of the battery cell is obtained by the second acquisition module 13; the first equalization time of the battery cell is calculated by the second calculation module 14 according to the first required equalization power and the current equalization current; the previous equalization time of the battery cell during the last charging and discharging process is obtained by the third acquisition module 15; the credibility of the battery cell is calculated by the third calculation module 16 according to the previous equalization time; the equalization time of the battery cell charging is calculated by the fourth calculation module 17 according to the first equalization time and the credibility, so that the equalization time of charging of a single battery cell can be accurately and reliably calculated, and when the battery is balanced, each battery cell can be balanced according to the equalization time of charging of each battery cell in the battery, so as to improve the accuracy of the equalization control of the entire battery, improve the efficiency of the equalization control of the battery, and thus effectively extend the service life of the battery.

[0238] Embodiment 8

[0239] The following is a discussion of the battery balancing control device provided in the embodiment of the present application. Fig.15 , Fig.15 It is a schematic diagram of a battery balancing control device provided in an embodiment of the present application. The battery balancing control device 3 includes an acquisition module 31, which is used to respectively acquire the balancing time of charging each of the battery cells, and the balancing time of charging the battery cells is calculated by the calculation method of the balancing time of the battery cells mentioned above; a control module 32, which is used to perform balancing control on the battery according to the balancing time of charging each of the battery cells.

[0240] In some embodiments, the plurality of battery cells include odd-numbered battery cells and even-numbered battery cells, and the odd-numbered battery cells and the even-numbered battery cells have the same preset balancing time. The control module 32 further includes a control unit 321, which is used to perform balancing control on the battery according to a balancing cycle. In one balancing cycle, the odd-numbered battery cells are balanced according to the preset balancing time, the battery is controlled to stop balancing according to an interval time, and the even-numbered battery cells are balanced according to the preset balancing time; an acquisition unit 322 is used to obtain the maximum value of the balancing time of each battery cell as the balancing maximum value; a calculation unit 323 is used to calculate the number of balancing times according to the balancing maximum value and the preset balancing time; and a balancing unit 324 is used to perform balancing control on the battery according to the balancing cycle and the number of balancing times.

[0241] In some embodiments, the control unit 321 is specifically used to perform balancing control on the odd-numbered battery cells according to the preset balancing time; obtain the heat value of the battery; compare the heat value with a first threshold and a second threshold; when the heat value is greater than the first threshold, control to increase the interval time, control the battery to stop balancing according to the increased interval time, and perform balancing control on the even-numbered battery cells according to the preset balancing time; when the heat value is less than the second threshold, control to reduce the interval time, control the battery to stop balancing according to the reduced interval time, and perform balancing control on the even-numbered battery cells according to the preset balancing time.

[0242] In the embodiment of the present application, the equalization time of charging each of the battery cells is respectively obtained by the acquisition module 31, and the equalization time of charging the battery cells is calculated by the calculation method of the equalization time of the battery cells mentioned above; the battery is balanced controlled according to the equalization time of charging each of the battery cells by the control module 32, so that the equalization control of each battery cell in the battery can be performed based on the equalization time of charging each of the battery cells, so that the accuracy of the equalization control of the battery is high, the probability of misjudgment is small, and the reliability of the equalization control of the battery is good.

[0243] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Under the concept of the present application, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other changes in different aspects of the present application as above, which are not provided in detail for the sake of simplicity. Although the present application has been described in detail with reference to the aforementioned embodiments, a person of ordinary skill in the art should understand that the technical solutions described in the aforementioned embodiments can still be modified, or some of the technical features can be replaced by equivalents. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for calculating the balancing time of a battery cell, characterized in that: Applied to a battery, the battery comprises a plurality of the battery cells, and the method comprises: Real-time acquisition of current data and voltage data of the battery cell during charging and discharging; Calculating the first required balancing power of the battery cell at the end time of this charging according to the current data and the voltage data; Obtaining the current balancing current of the battery cell; Calculating a first balancing time of the battery cell according to the first amount of electricity to be balanced and the current balancing current; Obtaining the previous equalization time of the battery cell during the last charging and discharging process; Calculating the reliability of the battery cell according to the pre-balancing time; Calculating the equalization time for charging the battery cell according to the first equalization time and the credibility; The pre-balance time includes a first pre-balance time and a second pre-balance time, the first pre-balance time corresponds to the last charging process, the second pre-balance time corresponds to the last discharging process, and the formula for calculating the credibility based on the pre-balance time is: Among them, the K Credibility (i) is the credibility of the ith cell, m is an empirical value, and T FCellChg (i) is the first pre-balancing time of the ith cell, and T FCelldischg (i) is the second pre-balancing time of the i-th battery cell; Among them, the K Credibility (i) is greater than 1, the K Credibility (i) Take 1; The value of m includes 2, 2.2, 2.5, 2.7 or 3.

2. The method according to claim 1, characterized in that The method further comprises: Calculating the second required balancing quantity of the battery cell at the end time of this discharge according to the current data and the voltage data; Calculating a second balancing time of the battery cell according to the second amount of electricity to be balanced and the current balancing current; The balancing time of the battery cell discharge is calculated according to the second balancing time and the credibility.

3. The method according to any one of claims 1 to 2, characterized in that: The pre-equalization time includes a first pre-equalization time and a second pre-equalization time, and the step of obtaining the pre-equalization time of the battery cell during the last charging and discharging process includes: Acquiring the previous current data and the previous voltage data of the battery cell during the last charging and discharging process; Calculating a first front-required balancing power of the battery cell at a front charging cut-off time according to the front current data and the front voltage data; Calculating the second required balancing quantity of the battery cell at the previous discharge cut-off time according to the previous current data and the previous voltage data; Obtaining the front balancing current of the battery cell; Calculating the first pre-balancing time of the battery cell according to the first pre-balancing power and the pre-balancing current; The second pre-balancing time of the battery cell is calculated according to the second pre-balancing required electric quantity and the pre-balancing current.

4. The method according to claim 1, characterized in that: The formula for calculating the equalization time of the battery cell charging according to the first equalization time and the credibility is: T cellChgBalance (i)=T CellChg (i)XK Credibility (i) Among them, the T CellChgBalance (i) is the equalization time of charging the i-th battery cell, and T CellChg (i) is the first balancing time of the ith cell, and K Credibility (i) is the reliability of the i-th battery cell.

5. The method according to claim 1, characterized in that Before the step of calculating the first amount of electricity required to be balanced of the battery cell at the current charging cut-off time according to the current data and the voltage data, the method further includes: According to the voltage data, obtaining the charging terminal voltage of the battery cell in this charging process; Determining whether the charging terminal voltage is greater than a first voltage threshold; If yes, the step of calculating the first amount of electricity required to be balanced of the battery cell at the end time of this charging according to the current data and the voltage data is entered.

6. The method according to claim 1, characterized in that The step of calculating the first amount of electricity required to be balanced of the battery cell at the current charging cut-off time according to the current data and the voltage data comprises: According to the current data and the voltage data, respectively calculate the excess power of each of the battery cells from a first moment to the current charging cut-off moment to obtain a plurality of excess power, wherein the first moment is when the voltage of the battery cell reaches a first preset voltage, wherein the first preset voltage is between a discharge cut-off voltage and a charge cut-off voltage; A minimum value among the plurality of surplus electric quantities is obtained as a minimum charging value, wherein the first electric quantity to be balanced is a difference between the surplus electric quantity of the battery cell and the minimum charging value.

7. The method according to claim 1, characterized in that The step of obtaining the current balancing current of the battery cell comprises: Obtaining the current voltage of the battery cell at the current moment; Obtaining the balancing resistance of the battery cell; The current balancing current of the battery cell is obtained according to the current voltage and the balancing resistance.

8. A battery balancing control method, characterized in that: Applied to a battery, the battery comprises a plurality of the battery cells, and the method comprises: Obtaining respectively the equalization time of charging of each of the battery cells, wherein the equalization time of charging of the battery cells is calculated according to the method described in any one of claims 1 to 7; The battery is balanced and controlled according to the balancing time of charging each of the battery cells.

9. The method according to claim 8, characterized in that The plurality of battery cells include odd-numbered battery cells and even-numbered battery cells, and the odd-numbered battery cells and the even-numbered battery cells have the same preset balancing time. The step of performing balancing control on the battery according to the balancing time of charging of each of the battery cells includes: Performing balancing control on the battery according to a balancing cycle, performing balancing control on the odd-numbered cells according to the preset balancing time in one balancing cycle, controlling the battery to stop balancing according to an interval time, and performing balancing control on the even-numbered cells according to the preset balancing time; Obtaining a maximum value of the equalization time of charging of each of the battery cells as the equalization maximum value; Calculate the number of equalization times according to the equalization maximum value and the preset equalization time; The battery is balanced and controlled according to the balancing period and the balancing times.

10. The method according to claim 9, characterized in that The step of performing equalization control on the battery according to the equalization cycle comprises: Performing balancing control on the odd-numbered battery cells according to the preset balancing time; Obtaining the heat value of the battery; Comparing the heat value with a first threshold and a second threshold; When the heat generation is greater than the first threshold, the interval time is controlled to be increased, the battery is controlled to stop balancing according to the increased interval time, and the even-numbered battery cells are balanced according to the preset balancing time; When the heat value is less than the second threshold, the interval time is controlled to be reduced, the battery is controlled to stop balancing according to the reduced interval time, and the even-numbered battery cells are balanced according to the preset balancing time.

11. A device for calculating the equalization time of a battery cell, characterized in that: Applied to a battery, the battery comprises a plurality of the battery cells, and the device comprises: A first acquisition module, used for acquiring current data and voltage data of the battery cell in the process of charging and discharging in real time; A first calculation module, used for calculating a first required balancing power of the battery cell at the current charging cut-off time according to the current data and the voltage data; A second acquisition module, used for acquiring the current balancing current of the battery cell; A second calculation module, configured to calculate a first balancing time of the battery cell according to the first amount of electricity to be balanced and the current balancing current; A third acquisition module is used to obtain the previous equalization time of the battery cell during the last charging and discharging process; A third calculation module, used for calculating the credibility of the battery cell according to the pre-balancing time; A fourth calculation module, configured to calculate the equalization time for charging the battery cell according to the first equalization time and the credibility; The pre-balance time includes a first pre-balance time and a second pre-balance time, the first pre-balance time corresponds to the last charging process, the second pre-balance time corresponds to the last discharging process, and the formula for calculating the credibility based on the pre-balance time is: Among them, the K Credibility (i) is the credibility of the ith cell, m is an empirical value, and T FCellChg (i) is the first pre-balancing time of the ith cell, and T FCelldischg (i) is the second pre-balancing time of the i-th battery cell; Among them, the K Credibility (i) is greater than 1, the K Credibility (i) Take 1; The value of m includes 2, 2.2, 2.5, 2.7 or 3.

12. A battery balancing control device, characterized in that: Applied to a battery, the battery comprises a plurality of the battery cells, and the device comprises: An acquisition module, used to respectively acquire the equalization time of charging of each of the battery cells, wherein the equalization time of charging of the battery cells is calculated according to the method described in any one of claims 1 to 7; The control module is used to perform equalization control on the battery according to the equalization time of charging each of the battery cells.

13. A battery, characterized in that: include: at least one processor; as well as A memory, wherein the memory is communicatively connected to the at least one processor, the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the method according to any one of claims 1 to 10.

14. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program. When the computer program is executed by a processor, the processor performs the steps of the method according to any one of claims 1 to 10.

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