Battery system balancing method and device based on battery cell working status

Abstract

The present invention provides a battery system equalization method and device based on the working state of a battery cell, which relates to the technical field of battery equalization. After determining abnormally discharged batteries and abnormally charged batteries, as well as the target charge equalization energy of the target abnormally discharged batteries and the target discharge equalization energy of the target abnormally charged batteries, the method selects to charge and equalize each abnormally discharged battery cell in turn based on the target charge equalization energy of each abnormally discharged battery cell when the battery system is in a discharge state; and to discharge and equalize each abnormally charged battery cell in turn based on the target discharge equalization energy of each abnormally charged battery cell when the battery system is in a charge state. The present invention does not increase the working time of abnormal batteries, and therefore can avoid the accelerated aging of abnormal batteries and the technical problem of inconsistent aging of batteries in the battery system, thereby effectively extending the service life of the battery system.

Description

Technical Field

[0001] The present invention relates to the technical field of battery balancing, and in particular to a battery system balancing method and device based on the working state of a battery cell. Background Art

[0002] The energy storage system is a system that can store and supply electrical energy for a certain period of time. It can be used in conjunction with the power generation system as a cache for the power system. The energy storage system can be composed of rechargeable and dischargeable battery cells (also known as battery cells). Generally, a single battery cell has a low voltage and small energy. In order to increase the energy of the battery cell and adapt to the voltage level of the power generation system, multiple battery cells can be connected in series to form a battery system.

[0003] In actual applications, due to the differences between each battery cell, each battery cell takes different time to fully charge or discharge. There is not only inconsistency in the rated energy between each battery cell in the battery pack, but also inconsistency in the ratio of the remaining energy of the battery cell to its rated energy. In particular, the latter will cause the available energy of the battery system to be much lower than the sum of the energy of each battery cell. As the number of cycles increases, it will greatly affect the overall service life of the battery system. For example, after a charge or discharge is completed, the voltage of an individual battery cell will be higher than that of other batteries, or lower than that of other batteries.

[0004] To address the above issues, it is necessary to use balancing technology on the battery pack to improve the inconsistency between the cells. The usual practice is to discharge the cells with higher voltage than other cells and charge the cells with lower voltage than other cells when the battery system is in standby mode. However, this balancing method will cause abnormal cells to be charged and discharged more times than other cells, and will also extend the working time of abnormal cells, accelerate the aging of abnormal cells, increase the aging inconsistency of the battery system, and cause great damage to the service life of the battery system. Summary of the invention

[0005] The object of the present invention is to provide a battery system balancing method and device based on the working state of battery cells, so as to alleviate the technical problem of inconsistent aging of battery cells in the battery system existing in the battery system balancing method in the prior art.

[0006] In a first aspect, the present invention provides a battery system balancing method based on the working state of a battery cell, comprising: obtaining a first working voltage and a discharge voltage-energy curve of each battery cell in the battery system when the battery system is in a discharge completion state, and obtaining a second working voltage and a charge voltage-energy curve of each battery cell when the battery system is in a charge completion state; determining abnormally discharged batteries and abnormally charged batteries in the battery system based on the first working voltage and the second working voltage of all batteries; determining a target charge balancing energy of the target abnormally discharged battery cell based on the discharge voltage-energy curve of the target abnormally discharged battery cell, the first working voltage of all batteries and a preset discharge cut-off voltage; and And, based on the charging voltage-energy curve of the target abnormally charged cell, the second operating voltage of all cells and the preset charging cut-off voltage, determine the target discharge equalization energy of the target abnormally charged cell; wherein the target abnormally discharged cell represents any cell among the abnormally discharged cells; the target abnormally charged cell represents any cell among the abnormally charged cells; when it is determined that the battery system is in a discharging state, charge equalization is performed on each abnormally discharged cell in turn based on the target charge equalization energy of each abnormally discharged cell; when it is determined that the battery system is in a charging state, discharge equalization is performed on each abnormally charged cell in turn based on the target discharge equalization energy of each abnormally charged cell.

[0007] Optionally, based on the first operating voltage and the second operating voltage of all battery cells, abnormally discharged battery cells and abnormally charged battery cells in the battery system are determined, including: sorting the first operating voltages of all battery cells to determine the bit numbers of the N battery cells with the lowest voltages to obtain a first bit number set; sorting the second operating voltages of all battery cells to determine the bit numbers of the N battery cells with the highest voltages to obtain a second bit number set; determining repeated bit numbers in the first bit number set and the second bit number set; removing repeated bit numbers from the first bit number set, and treating the battery cells corresponding to the remaining bit numbers of the first bit number set as abnormally discharged battery cells; removing repeated bit numbers from the second bit number set, and treating the battery cells corresponding to the remaining bit numbers of the second bit number set as abnormally charged battery cells.

[0008] Optionally, based on the discharge voltage-energy curve of the target abnormally discharged battery cell, the first operating voltage of all battery cells and the preset discharge cut-off voltage, the target charging equalization energy of the target abnormally discharged battery cell is determined, including: calculating the first average operating voltage of the first remaining battery cells except the battery cells corresponding to the first number set based on the first operating voltage of all battery cells; determining the first energy corresponding to the first average operating voltage based on the discharge voltage-energy curve of the target abnormally discharged battery cell; determining the second energy corresponding to the preset discharge cut-off voltage based on the discharge voltage-energy curve of the target abnormally discharged battery cell; calculating the recharge energy of the target abnormally discharged battery cell from the preset discharge cut-off voltage to the first average operating voltage based on the first energy and the second energy; and using the recharge energy as the target charging equalization energy of the target abnormally discharged battery cell.

[0009] Optionally, based on the charging voltage-energy curve of the target abnormally charged cell, the second operating voltage of all cells and the preset charging cut-off voltage, the target discharge equalization energy of the target abnormally charged cell is determined, including: calculating the second average operating voltage of the second remaining cells excluding the cells corresponding to the second bit number set based on the second operating voltage of all cells; determining the third energy corresponding to the second average operating voltage based on the charging voltage-energy curve of the target abnormally charged cell; determining the fourth energy corresponding to the preset charging cut-off voltage based on the charging voltage-energy curve of the target abnormally charged cell; calculating the playback energy of the target abnormally charged cell from the preset charging cut-off voltage to the second average operating voltage based on the third energy and the fourth energy; and using the playback energy as the target discharge equalization energy of the target abnormally charged cell.

[0010] Optionally, the battery system balancing method is applied to a target energy storage system, the target energy storage system comprising: an energy storage inverter, a battery system, a voltage sampling circuit, a balancing circuit and a plurality of balancing selection switches; the energy storage inverter is respectively connected to the battery system and the balancing circuit, the battery system is charged and discharged through the energy storage inverter, and the energy storage inverter is used to send a charging status signal or a discharging status signal of the battery system to the balancing circuit; the balancing circuit is connected to the voltage sampling circuits of a plurality of battery cells in the battery system in a one-to-one correspondence through a plurality of balancing selection switches; wherein the on and off of the balancing selection switches are controlled by the balancing circuit; the voltage sampling circuit is connected to the battery cell through the voltage sampling circuit, for collecting the voltage of each battery cell, and sending the voltage collection result to the balancing circuit; after the balancing circuit receives the discharge status signal of the battery system, the balancing circuit performs charge balancing on each abnormally discharged battery cell in turn based on the target charge balancing energy of each abnormally discharged battery cell; after the balancing circuit receives the charge status signal of the battery system, the balancing circuit performs discharge balancing on each abnormally charged battery cell in turn based on the target discharge balancing energy of each abnormally charged battery cell.

[0011] Optionally, when it is determined that the battery system is in a discharging state, each abnormally discharged cell is charged and balanced in turn based on the target charging and balancing energy of each abnormally discharged cell, including: step 1.0, obtaining the discharge current of the battery system; step 1.1, the balancing circuit controls all balancing control switches to be disconnected, and then the voltage sampling circuit collects the current working voltage of the target abnormally discharged cell; step 1.2, the balancing circuit controls the balancing control switch connected to the target abnormally discharged cell to be closed, so as to configure a first preset balancing current for the target abnormally discharged cell, and last for a first preset time; wherein the first preset balancing current is less than the discharge current; step 1.3, based on the current working voltage, the first preset balancing current and the first preset time of the target abnormally discharged cell, calculate the current charging and balancing energy and the cumulative charging and balancing energy of the target abnormally discharged cell; step 1.4, repeating the above steps 1.1 to 1.3 until the cumulative charging and balancing energy of the target abnormally discharged cell reaches its target charging and balancing energy; step 1.5, repeating the above steps 1.1 to 1.4 until all abnormally discharged cells complete charging and balancing.

[0012] Optionally, when it is determined that the battery system is in a charging state, discharge equalization is performed on each abnormally charged cell in turn based on the target discharge equalization energy of each abnormally charged cell, including: step 2.0, obtaining the charging current of the battery system; step 2.1, the equalization circuit controls all equalization control switches to be disconnected, and then the voltage sampling circuit collects the current working voltage of the target abnormally charged cell; step 2.2, the equalization circuit controls the equalization control switch connected to the target abnormally charged cell to be closed, so as to configure a second preset equalization current for the target abnormally charged cell, and last for a second preset time; wherein the second preset equalization current is less than the charging current; step 2.3, based on the current working voltage of the target abnormally charged cell, the second preset equalization current and the second preset time, calculate the current discharge equalization energy and the cumulative discharge equalization energy of the target abnormally charged cell; step 2.4, repeating the above steps 2.1 to 2.3 until the cumulative discharge equalization energy of the target abnormally charged cell reaches its target discharge equalization energy; step 2.5, repeating the above steps 2.1 to 2.4 until all abnormally charged cells complete discharge equalization.

[0013] In a second aspect, the present invention provides a battery system balancing device based on the working state of a battery cell, comprising: an acquisition module, used to acquire a first operating voltage and a discharge voltage-energy curve of each battery cell in the battery system when the battery system is in a discharge completion state, and to acquire a second operating voltage and a charge voltage-energy curve of each battery cell when the battery system is in a charge completion state; a first determination module, used to determine abnormal discharge cells and abnormal charge cells in the battery system based on the first operating voltage and the second operating voltage of all battery cells; a second determination module, used to determine a target charge balancing of a target abnormal discharge cell based on the discharge voltage-energy curve of the target abnormal discharge cell, the first operating voltage of all battery cells and a preset discharge cut-off voltage. energy; and, based on the charging voltage-energy curve of the target abnormally charged cell, the second operating voltage of all the cells and the preset charging cut-off voltage, determining the target discharge equalization energy of the target abnormally charged cell; wherein the target abnormally discharged cell represents any cell among the abnormally discharged cells; the target abnormally charged cell represents any cell among the abnormally charged cells; a charging equalization module, for performing charge equalization on each abnormally discharged cell in turn based on the target charge equalization energy of each abnormally discharged cell when it is determined that the battery system is in a discharging state; a discharging equalization module, for performing discharge equalization on each abnormally charged cell in turn based on the target discharge equalization energy of each abnormally charged cell when it is determined that the battery system is in a charging state.

[0014] In a third aspect, the present invention provides an electronic device, including a memory and a processor, wherein the memory stores a computer program that can be run on the processor, and when the processor executes the computer program, the battery system balancing method based on the working status of the battery cell in any of the aforementioned embodiments is implemented.

[0015] In a fourth aspect, the present invention provides a computer-readable storage medium, which stores computer instructions. When the computer instructions are executed by a processor, the battery system balancing method based on the working status of the battery cell in any of the aforementioned embodiments is implemented.

[0016] The battery system equalization method based on the working state of the battery cell provided by the present invention, after determining the abnormal discharge battery cell and the abnormal charge battery cell, as well as the target charge equalization energy of the target abnormal discharge battery cell and the target discharge equalization energy of the target abnormal charge battery cell, selects to charge and equalize each abnormal discharge battery cell in turn based on the target charge equalization energy of each abnormal discharge battery cell when the battery system is in the discharge state; and, when the battery system is in the charge state, discharge and equalize each abnormal charge battery cell in turn based on the target discharge equalization energy of each abnormal charge battery cell. The present invention does not increase the working time of the abnormal battery cell additionally. Therefore, compared with the prior art method of charging / discharging and equalizing the abnormal battery cell when the battery system is in the standby state, the present invention can avoid the accelerated aging of the abnormal battery cell and the technical problem of inconsistent aging of the battery cells in the battery system, thereby effectively extending the service life of the battery system. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 A flowchart of a battery system balancing method based on the working state of a battery cell provided by an embodiment of the present invention;

[0019] Figure 2 It is a schematic diagram of a traditional energy storage system;

[0020] Figure 3 It is a schematic diagram of the battery health capacity SOH and SOC status of each battery cell in the battery system;

[0021] Figure 4 A schematic diagram of the battery health capacity SOH and SOC state of each battery cell before and after balancing of another battery system;

[0022] Figure 5 A schematic diagram of a target energy storage system provided by an embodiment of the present invention;

[0023] Figure 6 A schematic diagram of simultaneously sampling and balancing the cell voltage provided by an embodiment of the present invention;

[0024] Figure 7 A schematic diagram of a principle for balancing target abnormally discharged cells in a battery system provided by an embodiment of the present invention;

[0025] Figure 8A schematic diagram of a principle for balancing target abnormally charged cells in a battery system provided by an embodiment of the present invention;

[0026] Fig. 9 A functional module diagram of a battery system balancing device based on the working state of a battery cell provided by an embodiment of the present invention;

[0027] Fig.10 A schematic diagram of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0029] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] Some embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0031] Embodiment 1

[0032] Figure 1 A flowchart of a battery system balancing method based on the working state of a battery cell provided in an embodiment of the present invention is shown in FIG. Figure 1 As shown, the method specifically comprises the following steps:

[0033] Step S102, obtaining a first operating voltage and a discharge voltage-energy curve of each battery cell in the battery system when the battery system is in a discharge completion state, and obtaining a second operating voltage and a charge voltage-energy curve of each battery cell when the battery system is in a charge completion state.

[0034] Step S104: determining abnormally discharged cells and abnormally charged cells in the battery system based on the first operating voltages and the second operating voltages of all the cells.

[0035] Figure 2This is a schematic diagram of a traditional energy storage system. The energy storage system consists of an energy storage converter CN and a battery system. The battery system consists of a number of battery cells connected in series. In the embodiment of the present invention, the battery cell can be a single battery cell, a battery cell module consisting of a number of battery cells connected in series and in parallel, or a structure consisting of a number of battery cell modules connected in series. The energy storage converter is connected to the battery system, and the battery system is charged and discharged through the energy storage converter.

[0036] To use balancing technology on the battery system to improve the inconsistency between the cells, it is first necessary to determine the abnormal cells in the battery system. Abnormal cells, that is, the balancing object of the embodiment of the present invention, are divided into two types of abnormal cells in the embodiment of the present invention, one is abnormal discharge cells and abnormal charge cells. Therefore, on the one hand, the embodiment of the present invention needs to discharge the battery system until the working voltage of any cell in the battery system reaches the preset discharge cut-off voltage, at which time it is determined that the battery system is in the discharge completion state, and the first working voltage of each cell in the discharge completion state and the discharge voltage-energy curve of each cell are obtained. On the other hand, the battery system needs to be charged until the working voltage of any cell in the battery system reaches the preset charge cut-off voltage, at which time it is determined that the battery system is in the charge completion state, and the second working voltage of each cell in the charge completion state and the charge voltage-energy curve of each cell are obtained. The charge / discharge voltage-energy curve is a curve in which the battery energy changes with the battery charge / discharge voltage.

[0037] After determining the first operating voltage of all cells in the discharge completion state and the second operating voltage of all cells in the charge completion state, the cell voltages can be tested for consistency, thereby determining abnormally discharged cells and abnormally charged cells in the battery system.

[0038] Step S106, determining a target charge equalization energy of the target abnormally discharged cell based on the discharge voltage-energy curve of the target abnormally discharged cell, the first operating voltage of all cells, and the preset discharge cut-off voltage; and determining a target discharge equalization energy of the target abnormally charged cell based on the charge voltage-energy curve of the target abnormally charged cell, the second operating voltage of all cells, and the preset charge cut-off voltage.

[0039] After determining the abnormal discharge cells and abnormal charge cells, in order to improve the inconsistency between the cells, it is first necessary to determine the energy required for balancing each abnormal discharge cell and abnormal charge cell. Specifically, for the target abnormal discharge cell with a low voltage in the discharge completion state, it is necessary to recharge it from the preset discharge cut-off voltage to the average voltage of the normal discharge cell in the discharge completion state. According to the discharge voltage-energy curve of the target abnormal discharge cell, the recharge energy corresponding to the above recharge process can be determined. The embodiment of the present invention uses the above recharge energy as the target charging balancing energy for the target abnormal discharge cell. Among them, the target abnormal discharge cell represents any cell among the abnormal discharge cells; the normal discharge cell represents the cell other than the N cells with the lowest voltage in the battery system in the discharge completion state.

[0040] For the target abnormally charged cell with a high voltage in the charging completion state, it is necessary to replay it from the preset charging cut-off voltage to the average voltage of the normal charged cell in the charging completion state. According to the charging voltage-energy curve of the target abnormally charged cell, the replay energy corresponding to the above replay process can be determined. The embodiment of the present invention uses the above replay energy as the target discharge balancing energy of the target abnormally charged cell. Among them, the target abnormally charged cell represents any cell among the abnormally charged cells. The normally charged cell represents the cell other than the N cells with the highest voltage in the battery system in the charging completion state.

[0041] Step S108 : when it is determined that the battery system is in a discharging state, charge balancing is performed on each abnormally discharged cell in sequence based on a target charge balancing energy of each abnormally discharged cell.

[0042] Step S110 , when it is determined that the battery system is in a charging state, discharge balancing is performed on each abnormally charged cell in turn based on a target discharge balancing energy of each abnormally charged cell.

[0043] The existing battery system balancing method is to charge / discharge the abnormal cells separately when the battery system is in the standby state to improve the consistency between the cells. However, the above method makes the working time of the abnormal cells longer than that of the normal cells, which leads to faster aging of the abnormal cells, seriously affecting the overall life of the battery system. In order to solve the above problem, after determining the abnormal charging cells and abnormal discharging cells, the embodiment of the present invention selects to charge and balance the target abnormal discharging cells that need to be optimized for charge balance when the battery system is discharged next time according to the target charge balance energy corresponding to the target abnormal discharging cells, that is, charge and balance each abnormal discharging cell in turn; similarly, for the target abnormal charging cells that need to be optimized for discharge balance, select to discharge and balance them according to the target discharge balance energy corresponding to the target abnormal charging cells when the battery system is charged next time, that is, discharge and balance each abnormal charging cell in turn. Obviously, the method provided by the embodiment of the present invention does not increase the working time of the abnormal charging / discharging cells when balancing the battery system, that is, it avoids the problem that the abnormal charging / discharging cells age faster than the normal charging / discharging cells.

[0044] The battery system balancing method based on the working state of the battery cell provided in the embodiment of the present invention, after determining the abnormal discharge battery cell and the abnormal charge battery cell, as well as the target charge balancing energy of the target abnormal discharge battery cell and the target discharge balancing energy of the target abnormal charge battery cell, selects to charge and balance each abnormal discharge battery cell in turn based on the target charge balancing energy of each abnormal discharge battery cell when the battery system is in the discharge state; and, when the battery system is in the charge state, discharge and balance each abnormal charge battery cell in turn based on the target discharge balancing energy of each abnormal charge battery cell. The present invention does not increase the working time of the abnormal battery cell additionally. Therefore, compared with the prior art method of charging / discharging and balancing the abnormal battery cell when the battery system is in the standby state, the present invention can avoid the accelerated aging of the abnormal battery cell and the technical problem of inconsistent aging of the battery cells in the battery system, thereby effectively extending the service life of the battery system.

[0045] In an optional implementation, the above step S104, based on the first operating voltage and the second operating voltage of all the cells, determines the abnormally discharged cells and the abnormally charged cells in the battery system, specifically includes the following steps:

[0046] Step S1041 , sorting the first operating voltages of all the battery cells to determine the bit numbers of the N battery cells with the lowest voltages, and obtaining a first bit number set.

[0047] Step S1042, sorting the second operating voltages of all the battery cells to determine the bit numbers of the N battery cells with the highest voltages, and obtaining a second bit number set.

[0048] Step S1043, determining the repeated bit numbers of the first bit number set and the second bit number set.

[0049] Step S1044, removing duplicate bit numbers from the first bit number set, and taking the cells corresponding to the remaining bit numbers in the first bit number set as abnormally discharged cells.

[0050] Step S1045 , removing duplicate bit numbers from the second bit number set, and taking the cells corresponding to the remaining bit numbers in the second bit number set as abnormally charged cells.

[0051] Specifically, each battery cell in the battery system has a corresponding position number, that is, the number of the battery cells. After the battery system is discharged, the first working voltages of all the battery cells can be arranged in descending order, and then the battery cell position numbers corresponding to the N first working voltages with a lower ranking are stored in the first position number set, and the battery cells corresponding to the position numbers in the first position number set are suspected abnormal discharge batteries. Similarly, after the battery system is charged, the second working voltages of all the battery cells are arranged in descending order, and then the battery cell position numbers corresponding to the N second working voltages with a higher ranking are stored in the second position number set, and the battery cells corresponding to the position numbers in the second position number set are suspected abnormal charging batteries. The embodiment of the present invention does not specifically limit the value of N, and the user can make an adaptive setting according to the total number of battery cells in the battery system. In addition, you can also choose to use the preset abnormal battery cell ratio to determine the first position number set and the second position number set.

[0052] Figure 3 It is a schematic diagram of the battery health capacity SOH and SOC status of each battery cell in the battery system. Figure 3 In the figure, a rectangle corresponds to a cell, and the solid part is the SOH of the cell. It is known that the battery system is composed of multiple cells connected in series, and the SOC status of each cell may be inconsistent. When one of the cells reaches the upper voltage limit (that is, the preset charge cut-off voltage), the entire cell stops charging. When one of the cells reaches the lower voltage limit (that is, the preset discharge cut-off voltage), the entire cell stops discharging. The actual available capacity of the entire cell is reduced due to the inconsistent SOC of each cell. Figure 3 It can be seen that in this battery system, the battery charge / discharge ends at the same cell, that is, the lowest voltage at the end of discharge and the highest voltage at the end of charge are the same cell. It can be seen that the energy state consistency of each cell in this battery system can no longer improve the overall available energy of the battery system by balancing the cell state. In other words, Figure 3 The cells that cause the battery charge / discharge to be terminated are the cells corresponding to the repeated bit numbers of the first bit number set and the second bit number set. Obviously, the cells corresponding to the repeated bit numbers do not need to be balanced.

[0053] In the embodiment of the present invention, the cells corresponding to the remaining bit numbers except the repeated bit numbers in the first bit number set are regarded as abnormally discharged cells, and the cells corresponding to the remaining bit numbers except the repeated bit numbers in the second bit number set are regarded as abnormally charged cells. For example, if the first bit number set is {1,2,3,4} and the second bit number set is {1,2,5,6}, then the repeated bit numbers are {1,2}, the bit numbers of the abnormally discharged cells are {3,4}, and the bit numbers of the abnormally charged cells are {5,6}.

[0054] Figure 4 This is a schematic diagram of the battery health capacity SOH and SOC status of each battery cell before and after balancing of another battery system. Figure 4 It can be seen that the battery charge / discharge cutoff is not the same battery cell. After balancing the battery system, its actual available capacity is effectively improved.

[0055] In an optional embodiment, in the above step S106, based on the discharge voltage-energy curve of the target abnormally discharged battery cell, the first operating voltage of all the batteries and the preset discharge cut-off voltage, the target charge equalization energy of the target abnormally discharged battery cell is determined, which specifically includes the following steps:

[0056] Step S1061 , based on the first operating voltages of all the battery cells, calculating the first average operating voltages of the first remaining battery cells except the battery cells corresponding to the first number set.

[0057] According to the above description, the first remaining battery cells are the normally discharged battery cells, and the first average operating voltage is the average value of the first operating voltages of the normally discharged battery cells in the end-of-discharge state.

[0058] Step S1062: determining a first energy corresponding to a first average operating voltage based on a discharge voltage-energy curve of the target abnormally discharged battery cell.

[0059] That is, the energy corresponding to the first average working voltage in the discharge voltage-energy curve of the target abnormally discharged battery cell is taken as the first energy.

[0060] Step S1063: determining a second energy corresponding to a preset discharge cut-off voltage based on a discharge voltage-energy curve of the target abnormally discharged battery cell.

[0061] That is, the energy corresponding to the preset discharge cut-off voltage in the discharge voltage-energy curve of the target abnormal discharge battery cell is taken as the second energy.

[0062] Step S1064, based on the first energy and the second energy, calculating the recharging energy of the target abnormally discharged battery cell from the preset discharge cut-off voltage to the first average working voltage.

[0063] According to the method for determining the first energy and the second energy, the difference between the first energy and the second energy is the recharge energy of the target abnormally discharged battery cell from the preset discharge cut-off voltage to the first average operating voltage.

[0064] Step S1065: using the recharged energy as the target charging equalization energy of the target abnormally discharged battery cell.

[0065] In an optional embodiment, in the above step S106, based on the charging voltage-energy curve of the target abnormally charged cell, the second operating voltage of all cells and the preset charging cut-off voltage, the target discharge equalization energy of the target abnormally charged cell is determined, including:

[0066] Step S106a, based on the second operating voltages of all the battery cells, calculating the second average operating voltages of the second remaining battery cells except the battery cells corresponding to the second bit number set.

[0067] According to the above description, the second remaining battery cells are the normally charged battery cells, and the second average operating voltage is the average value of the second operating voltages of the normally charged battery cells in the charging end state.

[0068] Step S106b: determining a third energy corresponding to the second average operating voltage based on the charging voltage-energy curve of the target abnormally charged battery cell.

[0069] That is, the energy corresponding to the second average working voltage in the charging voltage-energy curve of the target abnormally charged battery cell is taken as the third energy.

[0070] Step S106c: determining a fourth energy corresponding to a preset charging cut-off voltage based on a charging voltage-energy curve of the target abnormally charged battery cell.

[0071] That is, the energy corresponding to the preset charging cut-off voltage in the charging voltage-energy curve of the target abnormally charged battery cell is used as the fourth energy.

[0072] Step S106d: Calculate the replay energy of the target abnormally charged cell from the preset charging cut-off voltage to the second average operating voltage based on the third energy and the fourth energy.

[0073] According to the method for determining the third energy and the fourth energy, the difference between the third energy and the fourth energy is the playback energy of the target abnormally charged cell from the preset charging cut-off voltage to the second average operating voltage.

[0074] Step S106e: Using the replayed energy as the target discharge balancing energy of the target abnormally charged cell.

[0075] In an optional implementation, the battery system balancing method is applied to a target energy storage system. Figure 5 The schematic diagram of the target energy storage system provided by the embodiment of the present invention is as follows: Figure 5 As shown, the target energy storage system includes: an energy storage converter CN, a battery system BAT, a voltage sampling circuit CY, a balancing circuit JH and a plurality of balancing gating switches K. Exemplarily, Figure 5 The battery system in the is composed of 3 cells.

[0076] The energy storage converter is connected to the battery system and the equalization circuit respectively. The battery system is charged and discharged through the energy storage converter. The energy storage converter is used to send a charging state signal or a discharging state signal of the battery system to the equalization circuit.

[0077] The balancing circuit is connected to the voltage sampling circuits of multiple cells in the battery system in a one-to-one correspondence through multiple balancing selection switches; wherein the on and off of the balancing selection switches are controlled by the balancing circuit.

[0078] The voltage sampling circuit is connected to the battery cell through a voltage sampling line, and is used to collect the voltage of each battery cell and send the voltage collection result to the balancing circuit.

[0079] After receiving the discharge state signal of the battery system, the equalization circuit performs charge equalization on each abnormally discharged cell in turn based on the target charge equalization energy of each abnormally discharged cell.

[0080] After receiving the charging state signal of the battery system, the balancing circuit performs discharge balancing on each abnormally charged cell in turn based on the target discharge balancing energy of each abnormally charged cell.

[0081] The method provided in the embodiment of the present invention is executed by a balancing circuit. The balancing circuit can be an inductive, capacitive, flyback, resistive, or other circuit. The power supply of the balancing circuit is taken from the total positive and negative of the battery system. That is, when a certain battery cell is balanced, the energy required for the balancing of the battery cell comes from the entire battery system, which together provide balancing capability to the balancing circuit.

[0082] Figure 5 In the example, the balancing circuit is connected to the voltage sampling circuit of each cell through the balancing selection switch (K1, K2, K3), and the voltage sampling circuit is also the circuit between the cell and the voltage sampling circuit. According to the circuit connection relationship, only one group of balancing selection switches (K1, K2, K3) is allowed to be in the closed state at the same time to avoid direct connection between cells and abnormal changes in the cell connection topology.

[0083] In addition, the voltage sampling circuit in the embodiment of the present invention is a time-sharing multiplexed circuit of the voltage sampling circuit and the balancing circuit, that is, the voltage sampling circuit serves as both a circuit of the voltage sampling circuit and a circuit of the balancing circuit, but sampling and balancing are not performed at the same time. Specifically, when the balancing circuit balances a certain battery cell, since the working current of the battery cell is different from that of other battery cells, the voltage change of the battery cell will be different from that of other battery cells; at the same time, when the balancing current flows through the sampling circuit, a voltage drop is generated due to the circuit impedance, which will also affect the accuracy of the battery cell voltage sampling.

[0084] like Figure 6 As shown, when the balancing switch K1 is closed and the balancing current is I jc When the voltage sampling circuit collects the voltage U Sam =U cell +U R =U cell +I jc *I R , where U cell Indicates the actual voltage of the battery cell, U R Indicates the balancing current I jc The voltage generated on the voltage sampling line impedance R. Obviously, if I jc ≠0, there must be a deviation between the voltage sampling result of the voltage sampling circuit and the actual voltage of the battery cell. Therefore, in order to avoid the above problem, in the embodiment of the present invention, when sampling the voltage of a certain battery cell, the balancing circuit controls the balancing control switch connected to the battery cell to be disconnected. At this time, the balancing current I jc =0; when balancing a certain battery cell, the balancing circuit controls the balancing control switch connected to the battery cell to close. The above method can ensure that the battery cell voltage sampling result and the balancing energy can achieve high accuracy.

[0085] In the embodiment of the present invention, the channels for the voltage sampling circuit to sample the voltage of each cell are electrically isolated from each other. The balancing current of the balancing circuit during operation needs to be controlled within the overcurrent capacity of the voltage sampling circuit to avoid circuit damage. Generally, the balancing current is 0-5 A. In the embodiment of the present invention, the balancing circuit configures the target abnormally discharged cell with a first preset balancing current to achieve the transmission of the target charging balancing energy, and the balancing circuit configures the target abnormally charged cell with a second preset balancing current to achieve the transmission of the target discharge balancing energy.

[0086] In an optional implementation, in the above step S108, when it is determined that the battery system is in a discharging state, charging and balancing each abnormally discharged cell in turn based on the target charging and balancing energy of each abnormally discharged cell includes:

[0087] Step 1.0, obtaining the discharge current of the battery system.

[0088] Step 1.1, the balancing circuit controls all balancing control switches to be disconnected, and then the voltage sampling circuit collects the current working voltage of the target abnormally discharged battery cell.

[0089] Figure 7 A schematic diagram of a principle for balancing a target abnormally discharged battery cell in a battery system provided by an embodiment of the present invention, Figure 7 Taking the target abnormal discharge cell as cell1 as an example, when executing steps 1.0-1.1, all balancing control switches are disconnected. At this time, the working current (discharging current in this state) of all cells is I bat =I1+I2, where I1 is the discharge current of the battery system through the energy storage converter, I2 is the working current of the balancing circuit, and I2 is less than I1. Optionally, when collecting voltage, if the voltage change of the target abnormal discharge cell is less than 1mV within 3 consecutive seconds, it is used as the current working voltage U of the target abnormal discharge cell. cell1 .

[0090] Step 1.2, the balancing circuit controls the balancing control switch connected to the target abnormally discharged battery cell to close, so as to configure a first preset balancing current for the target abnormally discharged battery cell and last for a first preset time; wherein the first preset balancing current is smaller than the discharge current.

[0091] Step 1.3, based on the current operating voltage, the first preset balancing current and the first preset duration of the target abnormally discharged battery cell, calculate the current charging balancing energy and the accumulated charging balancing energy of the target abnormally discharged battery cell.

[0092] To charge cell1 equally, the equalization circuit needs to control the equalization control switch K1 to close, and then the first preset equalization current I jc The first preset duration T1 is continuously applied to cell1, and I jc bat At this time, the working current of cell1 is I cell1 =I bat -I jc The operating current of cell2 and cell3 is still I bat I cell1 <I bat That is, the working current of cell 1 is smaller than that of other cells, and cell 1 is in a slow discharge state relative to other cells. Under the action of the first preset equalization current of the first preset time, the current charging equalization energy E of the target abnormal discharge cell cell1-c =U cell1 *I jc *T1, accumulated charging equalization energy E c =∑E cell1-c .​

[0093] Step 1.4, repeating the above steps 1.1 to 1.3 until the accumulated charge balancing energy of the target abnormally discharged battery cell reaches its target charge balancing energy.

[0094] Since the cell voltage is constantly changing during the discharge process, in order to ensure the accuracy of the calculation of charge balancing energy, it is necessary to periodically sample the cell voltage and then balance it. The duration of each balancing of abnormally discharged cells needs to be set according to the actual situation. jc To charge, when E c =E c-top When the target abnormal discharge cell completes charge equalization, E c-top Indicates the target charge equalization energy of the target abnormally discharged cell.

[0095] Step 1.5: Repeat steps 1.1 to 1.4 until all abnormally discharged cells are charged and balanced.

[0096] In an optional implementation, in the above step S110, when it is determined that the battery system is in a charging state, discharging and balancing each abnormally charged cell in turn based on a target discharging and balancing energy of each abnormally charged cell includes:

[0097] Step 2.0, obtaining the charging current of the battery system.

[0098] Step 2.1, the balancing circuit controls all balancing control switches to be disconnected, and then the voltage sampling circuit collects the current operating voltage of the target abnormal charging cell.

[0099] Figure 8 A schematic diagram of a principle for balancing target abnormally charged cells in a battery system provided by an embodiment of the present invention, Figure 8 Taking the target abnormal charging cell as cell3 as an example, when executing steps 2.0-2.1, all balancing control switches are disconnected. At this time, the working current (charging current in this state) of all cells is I bat =I1-I2, where I1 is the charging current of the battery system through the energy storage converter, I2 is the working current of the balancing circuit, and I2 is less than I1. Optionally, when collecting voltage, if the voltage change of the target abnormal charging cell is less than 1mV within 3 consecutive seconds, it is used as the current working voltage U of the target abnormal charging cell. cell3 .

[0100] Step 2.2, the balancing circuit controls the balancing control switch connected to the target abnormally charged cell to close, so as to configure a second preset balancing current for the target abnormally charged cell and last for a second preset time; wherein the second preset balancing current is smaller than the charging current.

[0101] Step 2.3, based on the current operating voltage, the second preset balancing current and the second preset time of the target abnormally charged cell, calculate the current discharge balancing energy and the accumulated discharge balancing energy of the target abnormally charged cell.

[0102] To discharge cell 3, the balancing circuit needs to control the balancing control switch K3 to close, and then the second preset balancing current I jd The second preset time T2 is continuously applied to cell3, and I jd bat At this time, the working current of cell3 is I cell3 =I bat -I jd The operating current of cell1 and cell2 is still I bat I cell3 <I bat That is, the working current of cell 3 is smaller than that of other cells, and cell 3 is in a slow charging state relative to other cells. Under the action of the second preset balancing current of the second preset time, the current discharge balancing energy E of the target abnormally charged cell cell3-d =U cell3 *I jd *T2, cumulative discharge balance energy E d =∑E cell3-d .

[0103] Step 2.4, repeating the above steps 2.1 to 2.3 until the accumulated discharge balancing energy of the target abnormally charged cell reaches its target discharge balancing energy.

[0104] Similar to the charge equalization method, the cell voltage is constantly changing during the charging process. Therefore, in order to ensure the accuracy of the calculation of the discharge equalization energy, it is necessary to periodically sample the cell voltage and then equalize it. The duration of each equalization of abnormally charged cells needs to be set according to the actual situation. jd Discharge, when E d =E d-top When the target abnormally charged cell completes discharge balancing, E d-top Indicates the target discharge balancing energy of the target abnormally charged cell.

[0105] Step 2.5: Repeat steps 2.1 to 2.4 until all abnormally charged cells have completed discharge balancing. ​

[0106] Embodiment 2

[0107] An embodiment of the present invention further provides a battery system balancing device based on the working state of a battery cell. The device is mainly used to execute the battery system balancing method based on the working state of a battery cell provided in the first embodiment above. The battery system balancing device based on the working state of a battery cell provided in an embodiment of the present invention is specifically introduced below.

[0108] Fig. 9 is a functional module diagram of a battery system balancing device based on the working state of a battery cell provided by an embodiment of the present invention, such as Fig. 9 As shown, the device mainly includes: an acquisition module 10, a first determination module 20, a second determination module 30, a charging equalization module 40, and a discharging equalization module 50, wherein:

[0109] The acquisition module 10 is used to acquire the first operating voltage and the discharge voltage-energy curve of each battery cell in the battery system when the battery system is in a discharge completion state, and to acquire the second operating voltage and the charge voltage-energy curve of each battery cell when the battery system is in a charge completion state.

[0110] The first determination module 20 is used to determine abnormally discharged cells and abnormally charged cells in the battery system based on the first operating voltages and the second operating voltages of all the cells.

[0111] The second determination module 30 is used to determine the target charging equalization energy of the target abnormally discharged cell based on the discharge voltage-energy curve of the target abnormally discharged cell, the first operating voltage of all cells and the preset discharge cut-off voltage; and determine the target discharge equalization energy of the target abnormally charged cell based on the charging voltage-energy curve of the target abnormally charged cell, the second operating voltage of all cells and the preset charge cut-off voltage; wherein the target abnormally discharged cell represents any cell among the abnormally discharged cells; and the target abnormally charged cell represents any cell among the abnormally charged cells.

[0112] The charging equalization module 40 is used to perform charging equalization on each abnormally discharged cell in turn based on a target charging equalization energy of each abnormally discharged cell when it is determined that the battery system is in a discharging state.

[0113] The discharge balancing module 50 is used to perform discharge balancing on each abnormally charged cell in turn based on a target discharge balancing energy of each abnormally charged cell when it is determined that the battery system is in a charging state.

[0114] The battery system balancing device based on the working state of the battery cell provided in the embodiment of the present invention, after determining the abnormal discharge battery cell and the abnormal charge battery cell, as well as the target charge balancing energy of the target abnormal discharge battery cell and the target discharge balancing energy of the target abnormal charge battery cell, selects to charge and balance each abnormal discharge battery cell in turn based on the target charge balancing energy of each abnormal discharge battery cell when the battery system is in the discharge state; and, when the battery system is in the charge state, discharge and balance each abnormal charge battery cell in turn based on the target discharge balancing energy of each abnormal charge battery cell. The present invention does not increase the working time of the abnormal battery cell additionally. Therefore, compared with the prior art method of charging / discharging and balancing the abnormal battery cell when the battery system is in the standby state, the present invention can avoid the accelerated aging of the abnormal battery cell and the technical problem of inconsistent aging of the battery cells in the battery system, thereby effectively extending the service life of the battery system.

[0115] Optionally, the first determining module 20 is specifically configured to:

[0116] The first operating voltages of all battery cells are sorted to determine the position numbers of the N battery cells with the lowest voltages, and obtain a first position number set.

[0117] The second operating voltages of all battery cells are sorted to determine the bit numbers of the N battery cells with the highest voltages, and obtain a second bit number set.

[0118] Determine the repeated bit numbers of the first bit set and the second bit set.

[0119] The duplicate bit numbers are removed from the first bit number set, and the cells corresponding to the remaining bit numbers in the first bit number set are regarded as abnormally discharged cells.

[0120] Duplicate bit numbers are removed from the second bit number set, and the cells corresponding to the remaining bit numbers in the second bit number set are taken as abnormally charged cells.

[0121] Optionally, the second determining module 30 is specifically configured to:

[0122] Based on the first operating voltages of all the battery cells, a first average operating voltage of the first remaining battery cells except the battery cells corresponding to the first number set is calculated.

[0123] The first energy corresponding to the first average operating voltage is determined based on the discharge voltage-energy curve of the target abnormally discharged battery cell.

[0124] The second energy corresponding to the preset discharge cut-off voltage is determined based on the discharge voltage-energy curve of the target abnormal discharge cell.

[0125] Based on the first energy and the second energy, a recharge energy of the target abnormally discharged battery cell from a preset discharge cut-off voltage to a first average operating voltage is calculated.

[0126] The recharge energy is used as the target charging equalization energy of the target abnormally discharged battery cell.

[0127] Optionally, the second determining module 30 is further configured to:

[0128] Based on the second operating voltages of all the battery cells, a second average operating voltage of the second remaining battery cells except the battery cells corresponding to the second bit number set is calculated.

[0129] The third energy corresponding to the second average operating voltage is determined based on the charging voltage-energy curve of the target abnormally charged battery cell.

[0130] A fourth energy corresponding to a preset charging cut-off voltage is determined based on a charging voltage-energy curve of the target abnormally charged battery cell.

[0131] Based on the third energy and the fourth energy, the replayed energy of the target abnormally charged cell from the preset charging cut-off voltage to the second average operating voltage is calculated.

[0132] The replayed energy is used as the target discharge balancing energy of the target abnormally charged cell.

[0133] Optionally, the battery system balancing method is applied to a target energy storage system, and the target energy storage system includes: an energy storage converter, a battery system, a voltage sampling circuit, a balancing circuit, and a plurality of balancing selection switches.

[0134] The energy storage converter is connected to the battery system and the equalization circuit respectively. The battery system is charged and discharged through the energy storage converter. The energy storage converter is used to send a charging state signal or a discharging state signal of the battery system to the equalization circuit.

[0135] The balancing circuit is connected to the voltage sampling circuits of multiple cells in the battery system in a one-to-one correspondence through multiple balancing selection switches; wherein the on and off of the balancing selection switches are controlled by the balancing circuit.

[0136] The voltage sampling circuit is connected to the battery cell through a voltage sampling line, and is used to collect the voltage of each battery cell and send the voltage collection result to the balancing circuit.

[0137] After receiving the discharge state signal of the battery system, the equalization circuit performs charge equalization on each abnormally discharged cell in turn based on the target charge equalization energy of each abnormally discharged cell.

[0138] After receiving the charging state signal of the battery system, the balancing circuit performs discharge balancing on each abnormally charged cell in turn based on the target discharge balancing energy of each abnormally charged cell.

[0139] Optionally, the charging equalization module 40 is used for:

[0140] Step 1.0, obtaining the discharge current of the battery system.

[0141] Step 1.1, the balancing circuit controls all balancing control switches to be disconnected, and then the voltage sampling circuit collects the current working voltage of the target abnormally discharged battery cell.

[0142] Step 1.2, the balancing circuit controls the balancing control switch connected to the target abnormally discharged battery cell to close, so as to configure a first preset balancing current for the target abnormally discharged battery cell and last for a first preset time; wherein the first preset balancing current is smaller than the discharge current.

[0143] Step 1.3, based on the current operating voltage, the first preset balancing current and the first preset duration of the target abnormally discharged battery cell, calculate the current charging balancing energy and the accumulated charging balancing energy of the target abnormally discharged battery cell.

[0144] Step 1.4, repeating the above steps 1.1 to 1.3 until the accumulated charge balancing energy of the target abnormally discharged battery cell reaches its target charge balancing energy.

[0145] Step 1.5: Repeat steps 1.1 to 1.4 until all abnormally discharged cells are charged and balanced.

[0146] Optionally, the discharge equalization module 50 is used for:

[0147] Step 2.0, obtaining the charging current of the battery system.

[0148] Step 2.1, the balancing circuit controls all balancing control switches to be disconnected, and then the voltage sampling circuit collects the current operating voltage of the target abnormal charging cell.

[0149] Step 2.2, the balancing circuit controls the balancing control switch connected to the target abnormally charged cell to close, so as to configure a second preset balancing current for the target abnormally charged cell and last for a second preset time; wherein the second preset balancing current is smaller than the charging current.

[0150] Step 2.3, based on the current operating voltage, the second preset balancing current and the second preset time of the target abnormally charged cell, calculate the current discharge balancing energy and the accumulated discharge balancing energy of the target abnormally charged cell.

[0151] Step 2.4, repeating the above steps 2.1 to 2.3 until the accumulated discharge balancing energy of the target abnormally charged cell reaches its target discharge balancing energy.

[0152] Step 2.5: Repeat steps 2.1 to 2.4 until all abnormally charged cells have completed discharge balancing.

[0153] Embodiment 3

[0154] See also Fig.10 An embodiment of the present invention provides an electronic device, which includes: a processor 60, a memory 61, a bus 62 and a communication interface 63, the processor 60, the communication interface 63 and the memory 61 are connected through the bus 62; the processor 60 is used to execute an executable module stored in the memory 61, such as a computer program.

[0155] The memory 61 may include a high-speed random access memory (RAM), and may also include a non-volatile memory, such as at least one disk memory. The communication connection between the system network element and at least one other network element is realized through at least one communication interface 63 (which may be wired or wireless), and the Internet, wide area network, local area network, metropolitan area network, etc. may be used.

[0156] The bus 62 may be an ISA bus, a PCI bus, or an EISA bus. The bus may be divided into an address bus, a data bus, a control bus, and the like. For ease of representation, Fig.10 Only one bidirectional arrow is used in the diagram, but this does not mean that there is only one bus or only one type of bus.

[0157] Among them, the memory 61 is used to store programs, and the processor 60 executes the program after receiving the execution instruction. The method executed by the device defined by the process disclosed in any embodiment of the above-mentioned embodiment of the present invention can be applied to the processor 60 or implemented by the processor 60.

[0158] The processor 60 may be an integrated circuit chip with signal processing capabilities. In the implementation process, each step of the above method can be completed by the hardware integrated logic circuit or software instructions in the processor 60. The above processor 60 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 gates or transistor logic devices, discrete hardware components. The methods, steps and logic block diagrams disclosed in the embodiments of the present invention can be implemented or executed. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor. The steps of the method disclosed in the embodiments of the present invention can be directly embodied as a hardware decoding processor to be executed, or the hardware and software modules in the decoding processor can be executed. The software module can be located in a mature storage medium in the field such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory or an electrically erasable programmable memory, a register, etc. The storage medium is located in the memory 61, and the processor 60 reads the information in the memory 61 and completes the steps of the above method in combination with its hardware.

[0159] A computer program product of a battery system balancing method and device based on the working status of a battery cell provided in an embodiment of the present invention includes a computer-readable storage medium storing a non-volatile program code executable by a processor. The instructions included in the program code can be used to execute the method in the previous method embodiment. For specific implementation, please refer to the method embodiment, which will not be repeated here.

[0160] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0161] If the function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a non-volatile computer-readable storage medium that is executable by a processor. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods of each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc. Various media that can store program codes.

[0162] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0163] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or the positions or positional relationships in which the product of the invention is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0164] In addition, the terms "horizontal", "vertical", "overhanging" and the like do not mean that the components are required to be absolutely horizontal or overhanging, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0165] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0166] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A battery system balancing method based on the working state of a battery cell, characterized in that: include: Acquire a first operating voltage and a discharge voltage-energy curve of each battery cell in the battery system when the battery system is in a discharge completion state, and acquire a second operating voltage and a charge voltage-energy curve of each battery cell when the battery system is in a charge completion state; Determining abnormally discharged cells and abnormally charged cells in the battery system based on the first operating voltage and the second operating voltage of all the cells; Determining a target charging equalization energy of the target abnormally discharged battery cell based on a discharge voltage-energy curve of the target abnormally discharged battery cell, a first operating voltage of all the battery cells, and a preset discharge cut-off voltage; And, based on the charging voltage-energy curve of the target abnormally charged cell, the second operating voltage of all cells and the preset charging cut-off voltage, determine the target discharge balancing energy of the target abnormally charged cell; wherein the target abnormally discharged cell represents any cell among the abnormally discharged cells; the target abnormally charged cell represents any cell among the abnormally charged cells; When it is determined that the battery system is in a discharging state, charging and balancing each abnormally discharged cell in turn based on a target charging and balancing energy of each abnormally discharged cell; When it is determined that the battery system is in a charging state, discharging and balancing each abnormally charged cell in turn based on a target discharge balancing energy of each abnormally charged cell; Wherein, based on the first operating voltage and the second operating voltage of all the cells, determining the abnormally discharged cells and the abnormally charged cells in the battery system includes: The first operating voltages of all battery cells are sorted to determine the bit numbers of the N battery cells with the lowest voltages, and obtain a first bit number set; The second operating voltages of all battery cells are sorted to determine the bit numbers of the N battery cells with the highest voltages, and obtain a second bit number set; Determine the repeated bit numbers of the first bit number set and the second bit number set; Eliminate the repeated bit numbers from the first bit number set, and use the cells corresponding to the remaining bit numbers in the first bit number set as the abnormally discharged cells; Eliminate the repeated bit numbers from the second bit number set, and use the cells corresponding to the remaining bit numbers in the second bit number set as the abnormally charged cells; Wherein, based on the discharge voltage-energy curve of the target abnormally discharged battery cell, the first operating voltage of all the batteries and the preset discharge cut-off voltage, determining the target charge equalization energy of the target abnormally discharged battery cell includes: Based on the first operating voltages of all the battery cells, calculating a first average operating voltage of first remaining battery cells except the battery cells corresponding to the first bit number set; Determining a first energy corresponding to the first average operating voltage based on a discharge voltage-energy curve of the target abnormally discharged battery cell; Determining a second energy corresponding to the preset discharge cut-off voltage based on a discharge voltage-energy curve of the target abnormally discharged battery cell; Based on the first energy and the second energy, calculating the recharge energy of the target abnormally discharged battery cell from the preset discharge cut-off voltage to the first average operating voltage; Using the recharged energy as the target charging equalization energy of the target abnormally discharged battery cell; Wherein, based on the charging voltage-energy curve of the target abnormally charged cell, the second operating voltage of all cells and the preset charging cut-off voltage, determining the target discharge equalization energy of the target abnormally charged cell includes: Based on the second operating voltages of all the battery cells, calculating a second average operating voltage of second remaining battery cells except the battery cells corresponding to the second bit number set; Determining a third energy corresponding to the second average operating voltage based on a charging voltage-energy curve of the target abnormally charged battery cell; Determining a fourth energy corresponding to the preset charging cut-off voltage based on a charging voltage-energy curve of the target abnormally charged battery cell; Based on the third energy and the fourth energy, calculating the replay energy of the target abnormally charged cell from the preset charging cut-off voltage to the second average operating voltage; The playback energy is used as the target discharge balancing energy of the target abnormally charged battery cell.

2. The battery system balancing method based on the working status of the battery cell according to claim 1, characterized in that: The battery system balancing method is applied to a target energy storage system, wherein the target energy storage system comprises: an energy storage converter, a battery system, a voltage sampling circuit, a balancing circuit and a plurality of balancing gating switches; The energy storage converter is connected to the battery system and the equalizing circuit respectively, the battery system is charged and discharged through the energy storage converter, and the energy storage converter is used to send a charging state signal or a discharging state signal of the battery system to the equalizing circuit; The balancing circuit is connected to the voltage sampling circuits of the multiple cells in the battery system in a one-to-one correspondence through the multiple balancing gating switches; wherein the on and off of the balancing gating switches are controlled by the balancing circuit; The voltage sampling circuit is connected to the battery cell through the voltage sampling line, and is used to collect the voltage of each battery cell and send the voltage collection result to the balancing circuit; After receiving the discharge state signal of the battery system, the equalization circuit sequentially performs charge equalization on each abnormally discharged battery cell based on the target charge equalization energy of each abnormally discharged battery cell; After receiving the charging state signal of the battery system, the balancing circuit performs discharge balancing on each abnormally charged cell in turn based on the target discharge balancing energy of each abnormally charged cell.

3. The battery system balancing method based on the working status of the battery cell according to claim 2, characterized in that: When it is determined that the battery system is in a discharging state, each abnormally discharged cell is charged and balanced in turn based on a target charge and balance energy of each abnormally discharged cell, including: Step 1.0, obtaining the discharge current of the battery system; Step 1.1, the balancing circuit controls all balancing control switches to be turned off, and then the voltage sampling circuit collects the current working voltage of the target abnormally discharged battery cell; Step 1.2, the balancing circuit controls the balancing control switch connected to the target abnormally discharged battery cell to close, so as to configure a first preset balancing current for the target abnormally discharged battery cell and last for a first preset time; wherein the first preset balancing current is less than the discharge current; Step 1.3, calculating the current charging equalization energy and the accumulated charging equalization energy of the target abnormally discharged battery cell based on the current operating voltage of the target abnormally discharged battery cell, the first preset equalization current and the first preset time; Step 1.4, repeating the above steps 1.1 to 1.3 until the cumulative charge balancing energy of the target abnormally discharged battery cell reaches its target charge balancing energy; Step 1.5: Repeat steps 1.1 to 1.4 until all abnormally discharged cells are charged and balanced.

4. The battery system balancing method based on the working state of the battery cell according to claim 2, characterized in that: When it is determined that the battery system is in a charging state, each abnormally charged cell is discharged and balanced in turn based on a target discharge and balance energy of each abnormally charged cell, including: Step 2.0, obtaining the charging current of the battery system; Step 2.1, the balancing circuit controls all balancing control switches to be turned off, and then the voltage sampling circuit collects the current working voltage of the target abnormally charged battery cell; Step 2.2, the balancing circuit controls the balancing control switch connected to the target abnormally charged cell to close, so as to configure a second preset balancing current for the target abnormally charged cell and last for a second preset time; wherein the second preset balancing current is less than the charging current; Step 2.3, calculating the current discharge equalization energy and the accumulated discharge equalization energy of the target abnormally charged cell based on the current operating voltage of the target abnormally charged cell, the second preset equalization current and the second preset time; Step 2.4, repeating the above steps 2.1 to 2.3 until the cumulative discharge balancing energy of the target abnormally charged cell reaches its target discharge balancing energy; Step 2.5: Repeat steps 2.1 to 2.4 until all abnormally charged cells have completed discharge balancing.

5. A battery system balancing device based on the working state of a battery cell, characterized in that: include: An acquisition module, used to acquire a first operating voltage and a discharge voltage-energy curve of each battery cell in the battery system when the battery system is in a discharge completion state, and to acquire a second operating voltage and a charge voltage-energy curve of each battery cell when the battery system is in a charge completion state; A first determination module, configured to determine abnormally discharged cells and abnormally charged cells in the battery system based on the first operating voltage and the second operating voltage of all cells; A second determination module is used to determine a target charging equalization energy of the target abnormally discharged battery cell based on a discharge voltage-energy curve of the target abnormally discharged battery cell, a first operating voltage of all the batteries, and a preset discharge cut-off voltage; And, based on the charging voltage-energy curve of the target abnormally charged cell, the second operating voltage of all cells and the preset charging cut-off voltage, determine the target discharge balancing energy of the target abnormally charged cell; wherein the target abnormally discharged cell represents any cell among the abnormally discharged cells; the target abnormally charged cell represents any cell among the abnormally charged cells; A charging equalization module, for performing charge equalization on each abnormally discharged cell in turn based on a target charge equalization energy of each abnormally discharged cell when determining that the battery system is in a discharging state; A discharge balancing module, configured to perform discharge balancing on each abnormally charged cell in turn based on a target discharge balancing energy of each abnormally charged cell when determining that the battery system is in a charging state; Wherein, the first determination module is specifically used for: The first operating voltages of all battery cells are sorted to determine the bit numbers of the N battery cells with the lowest voltages, and obtain a first bit number set; The second operating voltages of all battery cells are sorted to determine the bit numbers of the N battery cells with the highest voltages, and obtain a second bit number set; Determine the repeated bit numbers of the first bit number set and the second bit number set; Eliminate the repeated bit numbers from the first bit number set, and use the cells corresponding to the remaining bit numbers in the first bit number set as the abnormally discharged cells; Eliminate the repeated bit numbers from the second bit number set, and use the cells corresponding to the remaining bit numbers in the second bit number set as the abnormally charged cells; Wherein, the second determination module is specifically used for: Based on the first operating voltages of all the battery cells, calculating a first average operating voltage of first remaining battery cells except the battery cells corresponding to the first bit number set; Determining a first energy corresponding to the first average operating voltage based on a discharge voltage-energy curve of the target abnormally discharged battery cell; Determining a second energy corresponding to the preset discharge cut-off voltage based on a discharge voltage-energy curve of the target abnormally discharged battery cell; Based on the first energy and the second energy, calculating the recharge energy of the target abnormally discharged battery cell from the preset discharge cut-off voltage to the first average operating voltage; Using the recharged energy as the target charging equalization energy of the target abnormally discharged battery cell; The second determination module is also used for: Based on the second operating voltages of all the battery cells, calculating a second average operating voltage of second remaining battery cells except the battery cells corresponding to the second bit number set; Determining a third energy corresponding to the second average operating voltage based on a charging voltage-energy curve of the target abnormally charged battery cell; Determining a fourth energy corresponding to the preset charging cut-off voltage based on a charging voltage-energy curve of the target abnormally charged battery cell; Based on the third energy and the fourth energy, calculating the replay energy of the target abnormally charged cell from the preset charging cut-off voltage to the second average operating voltage; The playback energy is used as the target discharge balancing energy of the target abnormally charged battery cell.

6. An electronic device comprising a memory and a processor, wherein the memory stores a computer program that can be run on the processor, wherein: When the processor executes the computer program, the battery system balancing method based on the working status of the battery cells according to any one of claims 1 to 4 is implemented.

7. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions, and when the computer instructions are executed by a processor, the battery system balancing method based on the working state of the battery cells according to any one of claims 1 to 4 is implemented.

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