Method for calculating actual capacity of battery cell and method for calculating SOC of battery cell

Abstract

The invention provides a calculation method for the actual capacity of a battery cell and a calculation method for the SOC of the battery cell. The method for calculating the actual capacity of the battery cell comprises the following steps: acquiring current data and voltage data of the battery cell in charging and discharging processes; calculating the total charging electric quantity and the total discharging electric quantity of the battery cell according to the current data and the voltage data; according to the current data and the voltage data, calculating the chargeable amount of the battery cell at the charging cut-off moment; according to the current data and the voltage data, calculating the dischargeable capacity of the battery cell at the discharge cut-off moment; obtaining the charging and discharging efficiency of the battery cell in the last full charging and discharging process; according to the total charging electric quantity, the total discharging electric quantity, the chargeable electric quantity, the dischargeable electric quantity and the charging and discharging efficiency, the actual capacity of the battery cell is calculated, the actual capacity of a single battery cell can be calculated, the SOH and the SOC of the single battery cell can be further calculated, the state of the single battery cell can be comprehensively known, and therefore efficient balancing of the battery can be achieved.

Description

Technical Field

[0001] The present application relates to the field of energy storage technology, and in particular to a method for calculating an actual capacity of a battery cell and a method for calculating a SOC of a battery cell. Background Art

[0002] In the field of energy storage, two or more battery 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 battery cells can be adjusted according to actual needs to adapt to different application scenarios and load requirements. Among them, the SOH (State of Health) of the battery cell is an important parameter to measure the performance and reliability of the battery cell. It reflects the aging and degradation of the battery cell with the increase of time and number of uses. In practical applications, the calculation of the SOH of the battery cell has important research significance.

[0003] The calculation of the SOH of a battery cell refers to the ability to accurately evaluate the health status of a single battery cell through precise data collection and analysis. This calculation requires the combination of multiple information, including parameters such as voltage, current, temperature during the charging and discharging process, as well as the historical data and characteristics of the battery cell. Through in-depth analysis and modeling of this data, an accurate estimate of the health status of a single battery cell can be obtained, usually expressed as a percentage. In general, the SOH of a battery cell can be calculated using the ratio of the actual capacity of the battery cell to the rated capacity of the battery cell. The actual capacity of the battery cell reflects the actual storage capacity of the battery cell in its current state, which is positively correlated with the SOH of the battery cell.

[0004] However, in the process of implementing the embodiments of the present application, the inventors of the present application found that the current battery is unable to calculate the actual capacity of a single battery cell and can only provide the actual capacity of the entire battery group. It is therefore impossible to further calculate the SOH of the battery cell, let alone fully understand the status of the battery cell. This may lead to misjudgment when managing the battery, limiting the effective management of the battery. Summary of the invention

[0005] In view of the above problems, the present application provides a method for calculating the actual capacity of a battery cell, which overcomes the above problems or at least partially solves the above problem of being unable to calculate the actual capacity of a single battery cell.

[0006] According to one aspect of the present application, a method for calculating the SOH 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: obtaining current data and voltage data of the battery cell during charging and discharging; calculating the total charge capacity and the total discharge capacity of the battery cell according to the current data and the voltage data; calculating the chargeable capacity of the battery cell at the charging cut-off time according to the current data and the voltage data; calculating the dischargeable capacity of the battery cell at the discharge cut-off time according to the current data and the voltage data; obtaining the charge and discharge efficiency of the battery cell during full charging and discharging; and calculating the actual capacity of the battery cell according to the total charge capacity, the total discharge capacity, the chargeable capacity, the dischargeable capacity, and the charge and discharge efficiency.

[0007] In an optional manner, the step of calculating the chargeable capacity of the battery cell at the charging cut-off moment according to the current data and the voltage data includes: calculating the charge capacity of each of the battery cells from a first moment to the charging cut-off moment according to the current data and the voltage data, to obtain multiple charge capacities, wherein at the first moment, 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 charging cut-off voltage; obtaining a maximum value among the multiple charge capacities as the charging maximum value, and the chargeable capacity is the difference between the charging maximum value and the charge capacity.

[0008] In an optional manner, the step of calculating the dischargeable amount of the battery cell at the discharge cut-off moment based on the current data and the voltage data includes: calculating the discharge amount of each of the battery cells from a second moment to the discharge cut-off moment based on the current data and the voltage data, to obtain multiple discharge amounts, wherein at the second moment, 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; obtaining a maximum value among the multiple discharge amounts as the discharge maximum value, and the dischargeable amount is the difference between the discharge maximum value and the discharge amount.

[0009] In an optional manner, the step of calculating the total charge capacity and the total discharge capacity of the battery cell based on the current data and the voltage data includes: calculating a first charge capacity of the battery cell from the start of charging to the first moment based on the current data and the voltage data, the total charge capacity being the sum of the first charge capacity and the charge capacity; calculating a first discharge capacity of the battery cell from the start of discharging to the second moment based on the current data and the voltage data, the total discharge capacity being the sum of the first discharge capacity and the discharge capacity.

[0010] In an optional manner, the step of obtaining the charging and discharging efficiency of the battery cell during the full charging and discharging process includes: obtaining the previous current data and the previous voltage data of the battery cell during the last full charging and discharging process; calculating the total charging capacity of the battery cell when fully charged and the total discharging capacity when fully discharged according to the previous current data and the previous voltage data; and calculating the charging and discharging efficiency of the battery cell according to the total charging capacity of the battery cell when fully charged and the total discharging capacity when fully discharged.

[0011] In an optional manner, the formula for calculating the charge and discharge efficiency of the battery cell according to the full charge total power and the full discharge total power is:

[0012]

[0013] Wherein, η is the charge and discharge efficiency, Q FComeCellDischg (i) is the total discharge capacity of the ith battery cell, and Q FComCellChg (i) is the total charging capacity of the i-th battery cell.

[0014] In an optional manner, the formula for calculating the actual capacity of the battery cell according to the total charged capacity, the total discharged capacity, the chargeable capacity, the dischargeable capacity, and the charge and discharge efficiency is:

[0015]

[0016] Among them, the Q CellMark (i) is the actual capacity of the ith battery cell, and Q ComCellChg (i) is the total charge capacity of the ith battery cell, and Q ComCellDischg (i) is the total discharge capacity of the ith battery cell, and Q PlusCellChg (i) is the chargeable capacity of the ith battery cell, and Q PlusCellDischg (i) is the dischargeable capacity of the i-th battery cell, and η is the charge and discharge efficiency.

[0017] According to one aspect of an embodiment of the present application, a method for calculating the SOH 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: obtaining the actual capacity as described above; obtaining the rated capacity of the battery cell; and calculating the SOH of the battery cell based on the actual capacity and the rated capacity.

[0018] According to one aspect of an embodiment of the present application, a method for calculating the SOC of a battery cell is provided, which is applied to a battery, wherein the battery includes multiple battery cells, and the method includes: obtaining the actual capacity as described above; calculating the cumulative power of the battery cell from the last SOC calculation moment to the current moment; obtaining the last SOC of the battery cell at the last SOC calculation moment; and calculating the SOC of the battery cell at the current moment based on the cumulative power, the last SOC, and the actual capacity.

[0019] In an optional manner, the formula for calculating the SOC of the battery cell according to the accumulated power, the remaining dischargeable capacity, and the actual capacity is:

[0020]

[0021] Wherein, SOC(i)t is the SOC of the ith cell at the current moment (t moment), SOC(i)t-1 is the SOC of the ith cell at the start of charging or discharging (t-1 moment), Q CellAccumualte (i) is the cumulative power of the ith battery cell, Q CellMark (i) is the actual capacity of the ith battery cell.

[0022] According to one aspect of an embodiment of the present application, a device for calculating the actual capacity of a battery cell is provided, which is applied to a battery, wherein the battery includes multiple battery cells, and the device includes: a first acquisition module, used to acquire current data and voltage data of the battery cell during charging and discharging; a first calculation module, used to calculate the total charge capacity and total discharge capacity of the battery cell based on the current data and voltage data; a second calculation module, used to calculate the chargeable capacity of the battery cell at the charging cut-off time based on the current data and voltage data; a third calculation module, used to calculate the dischargeable capacity of the battery cell at the discharge cut-off time based on the current data and voltage data; the second acquisition module, used to acquire the charge and discharge efficiency of the battery cell during full charging and discharging; and a fourth calculation module, used to calculate the actual capacity of the battery cell based on the total charge capacity, total discharge capacity, chargeable capacity, dischargeable capacity, and charge and discharge efficiency.

[0023] According to one aspect of an embodiment of the present application, a device for calculating the SOH of a battery cell is provided, which is applied to a battery, wherein the battery includes a plurality of battery cells, and the device includes: a third acquisition module, used to obtain the actual capacity as described above; a fourth acquisition module, used to obtain the rated capacity of the battery cell; and a fifth calculation module, used to calculate the SOH of the battery cell based on the actual capacity and the rated capacity.

[0024] According to one aspect of an embodiment of the present application, a device for calculating the SOC of a battery cell is provided, which is applied to a battery, wherein the battery includes multiple battery cells, and the device includes: a third acquisition module, used to obtain the actual capacity as described above; a sixth calculation module, used to calculate the cumulative power of the battery cell from the last SOC calculation moment to the current moment; a fourth acquisition module, used to obtain the last SOC of the battery cell at the last SOC calculation moment; and a seventh calculation module, used to calculate the SOC of the battery cell at the current moment based on the cumulative power, the last SOC, and the actual capacity.

[0025] 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.

[0026] 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.

[0027] The beneficial effects of the present application include: the calculation method of the actual capacity of the battery cell provided by the present application is applied to a battery, wherein the battery includes a plurality of battery cells, and the method includes: obtaining the current data and voltage data of the battery cell during the charging and discharging process; calculating the total charging capacity and the total discharging capacity of the battery cell according to the current data and voltage data; calculating the chargeable capacity of the battery cell at the charging cut-off time according to the current data and voltage data; calculating the dischargeable capacity of the battery cell at the discharging cut-off time according to the current data and voltage data; obtaining the charging and discharging efficiency of the battery cell during the full charging and discharging process; calculating the actual capacity of the battery cell according to the total charging capacity, the total discharging capacity, the chargeable capacity, the dischargeable capacity, and the charging and discharging efficiency. Through the above method, the actual capacity of a single battery cell can be calculated, and the SOH of a single battery cell can be further calculated, so that the health status of the battery can be accurately evaluated.

[0028] In other words, the present application starts from the actual charging and discharging behavior of the battery cell, through accurate calculation of the total charging capacity and the total discharging capacity, through accurate calculation of the chargeable capacity of the battery cell at the charging cut-off time, through accurate calculation of the dischargeable capacity of the battery cell at the discharging cut-off time, and combined with the charging and discharging efficiency of the battery cell, so as to accurately determine the actual capacity of the battery cell. This series of steps constitutes a complete actual capacity calculation process, and the actual capacity calculation method accurately determines the actual capacity of a single battery cell.

[0029] In addition, when combined with the rated capacity of the battery cell, the SOH of the battery cell can also be obtained, which can fully reflect the health status of the battery cell, enhance the ability to monitor battery performance, help extend the battery life and better achieve battery management, optimize the battery utilization efficiency, and ensure the safe operation of the battery.

[0030] In addition, by combining the accumulated power of the battery cell at the current moment, the last SOC and the actual capacity of the battery cell, the SOC of the battery cell at the current moment can also be obtained, which helps to optimize the management of the battery, improve energy utilization efficiency, and help understand the battery performance and control the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] 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.

[0032] Figure 1 is a schematic diagram of an application environment provided by an embodiment of the present application;

[0033] Figure 2 is a schematic diagram of the hardware structure of a battery provided in an embodiment of the present application;

[0034] Figure 3 It is a flow chart of a method for calculating the actual capacity of a battery cell provided in an embodiment of the present application;

[0035] Figure 4 It is a schematic diagram of a flow chart for calculating the chargeable capacity of a battery cell at the charging cut-off time provided in an embodiment of the present application;

[0036] Figure 5 It is a schematic diagram of a flow chart for calculating the dischargeable capacity of a battery cell at the discharge cut-off time provided in an embodiment of the present application;

[0037] Figure 6 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;

[0038] Figure 7 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;

[0039] Figure 8 is a schematic diagram of a flow chart for calculating charge and discharge efficiency provided in an embodiment of the present application;

[0040] Fig. 9 It is a flow chart of a method for calculating the SOH of a battery cell provided in an embodiment of the present application;

[0041] Fig.10 is a SOH distribution diagram of each battery cell provided in an embodiment of the present application;

[0042] Fig.11 is a flow chart of a method for calculating the SOC of a battery cell provided in an embodiment of the present application;

[0043] Fig.12 is a schematic diagram of a device for calculating the actual capacity of a battery cell provided in an embodiment of the present application;

[0044] Fig.13 is a schematic diagram of a device for calculating the SOH of a battery cell provided in an embodiment of the present application;

[0045] Fig.14 Schematic diagram of a device for calculating the SOC of a battery cell provided in an embodiment of the present application. DETAILED DESCRIPTION

[0046] 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.

[0047] 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.

[0048] See also Figure 1 , Figure 1 1 is a schematic diagram of an application environment provided by an embodiment of the present application, and the application environment is applicable to a method for calculating the actual capacity of the battery cell, a method for calculating the SOH of the battery cell, a method for calculating the SOC of the battery cell, a device for calculating the current capacity of the battery cell, a device for calculating the SOH of the battery cell, and a device for calculating the SOC of the battery cell. The application environment is a battery 100, and the battery 100 includes a plurality of battery cells 10. The plurality of battery cells 10 are connected in series.

[0049] 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 used for long-term storage and stable release of energy. Regardless of which type of battery, there is a charging and discharging process, and the battery needs to be safely monitored, so it is necessary to obtain the actual capacity of a single battery cell, obtain the SOH of a single battery cell, and obtain the SOC of a single battery cell.

[0050] 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 the 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.

[0051] In order to solve the technical problem in the prior art that the actual capacity of a single battery cell cannot be calculated, an embodiment of the present application provides a method for calculating the actual capacity of a battery cell.

[0052] Embodiment 1

[0053] Before introducing in detail the calculation method of the actual capacity of the battery cell, the hardware structure of the battery 100 provided in the embodiment of the present application is described.

[0054] See also Figure 2 , Figure 21 is a schematic diagram of the hardware structure of the battery provided in the embodiment of the present application. The battery can execute the calculation method of the actual capacity of the battery cell, the calculation method of the SOH of the battery cell, and the calculation method of the SOC of the battery cell. 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 are shown.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] Embodiment 2

[0059] 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.

[0060] 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.

[0061] 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.

[0062] Embodiment 3

[0063] The following is a discussion of a method for calculating the actual capacity of a battery cell provided in an embodiment of the present application, wherein the actual capacity of a battery cell reflects the actual storage capacity of the battery cell in the current state, which is positively correlated with the SOH of the battery cell. The current state is the state of the battery cell at the moment (when calculating the actual capacity of the battery cell). For example, after a battery cell leaves the factory and undergoes 10 charges and discharges, the actual capacity of the battery cell is calculated, and the current state is the state of the battery cell after it has undergone 10 charges and discharges since leaving the factory.

[0064] See also Figure 3 , Figure 3 : is a flow chart of a method for calculating the actual capacity of a battery cell provided in an embodiment of the present application, the method comprising the following steps:

[0065] Step S10, obtaining current data and voltage data of the battery cell during charging and discharging.

[0066] During charging, the current data are all current data from the start time of charging to the end time of charging, including the current-time curve during charging.

[0067] 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.

[0068] The charging cut-off time is the time when charging of the battery is stopped, that is, the charging cut-off time of each battery cell is the same. In some embodiments, when the voltage of one of the battery cells reaches the charging cut-off voltage, the charging cut-off time is reached. At this time, even if the voltage of other battery cells has not reached the charging cut-off voltage, charging of the battery is stopped.

[0069] During charging, the voltage data are all voltage data from the start time of charging to the end time of charging, including the voltage-time curve during charging.

[0070] During discharge, the current data are all current data from the start time of discharge to the end time of discharge, including the current-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.

[0072] The discharge cut-off time is the time when the discharge of the battery is stopped, that is, the discharge cut-off time of each battery cell is the same. In some embodiments, when the voltage of one of the battery cells reaches the discharge cut-off voltage, the discharge cut-off time is reached. At this time, even if the other battery cells have not reached the discharge cut-off voltage, the discharge of the battery is stopped.

[0073] During discharge, the voltage data are all voltage data from the discharge start time to the discharge end time, including the voltage-time curve during discharge.

[0074] 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.

[0075] It is worth noting that, since the battery cells in the battery are inconsistent, the current data of the battery cells are inconsistent and the voltage data of the battery cells are inconsistent during charging / discharging, that is, the voltages of the battery cells cannot be guaranteed to be consistent at the same time during charging / discharging; the current data of the battery cells are inconsistent and the voltage data of the battery cells are inconsistent during charging / discharging, that is, the voltages of the battery cells cannot be guaranteed to be consistent at the same time during charging / discharging.

[0076] It can be understood that the step S1, i.e., the step of obtaining the current data and voltage data of the battery cell during the charging and discharging process, actually obtains the current data and voltage data of each battery cell during the charging process, and obtains the current data and voltage data of each battery cell during the discharging process.

[0077] Step S20, calculating the total charge quantity and the total discharge quantity of the battery cell according to the current data and the voltage data.

[0078] The total charge capacity is the total charge capacity of the battery cells during the charging process, starting from the battery capacity of 0 to the end of full charge. During the charging process, the charging start time and the charging end time of each battery cell are the same, but each battery cell is inconsistent, so the total charge capacity of each battery cell is inconsistent.

[0079] The total discharge capacity is the total amount of electricity discharged by the battery cell during the discharge process from the full charge to the empty (full discharge) end of the battery. During the discharge process, the discharge start time of each battery cell is the same, and the discharge end time of each battery cell is the same, but since each battery cell is inconsistent, the total discharge capacity of each battery cell is inconsistent.

[0080] One method for calculating the total charging capacity of the battery cell is to obtain it according to the ampere-hour method, that is, during the charging process, from the charging start time to the charging end time, the change of the current of the battery cell over time is integrated to obtain the total charging capacity of the battery cell. The formula for the total charging capacity of the battery cell is:

[0081]

[0082] Among them, the Q ComCellChg (i) is the total charging capacity of the i-th battery cell, t0 is the charging start time, t2 is the charging end time, I(t) is the current during the charging process, and t is the time.

[0083] One method for calculating the total discharge capacity of the battery cell is to obtain it according to the ampere-hour method, that is, during the discharge process, from the discharge start time to the discharge end time, the change of the current of the battery cell over time is integrated to obtain the total discharge capacity of the battery cell. The formula for the total discharge capacity of the battery cell is:

[0084]

[0085] Among them, the Q ComCellDischg (i) is the total discharge capacity of the ith battery cell, and t 100is the discharge start time, t3 is the discharge end time, I(t) is the current during the discharge process, and t is the time.

[0086] It is worth noting that there may be other methods for calculating the total charging capacity of the battery cell, for example, according to the chargeable capacity in the following step S30; there may be other methods for calculating the total discharging capacity of the battery cell, for example, according to the dischargeable capacity in the following step S40. For details, please refer to the following steps S30 and S40, which will not be repeated here.

[0087] Step S30, calculating the chargeable capacity of the battery cell at the charging cut-off time according to the current data and the voltage data.

[0088] Due to the inconsistency of each of the battery cells, not all of the battery cells reach the discharge cut-off voltage when the charging cut-off time is reached, that is, at the charging cut-off time, the chargeable amount is the amount of electricity that can actually be charged in the battery cell when the battery is stopped from being charged.

[0089] It is worth noting that, in some embodiments, see Figure 4 , Figure 4 : is a flow chart of calculating the chargeable capacity of a battery cell at the charging cut-off time provided by an embodiment of the present application, that is, step S30 includes:

[0090] Step S301 , calculating the charging capacity of each of the battery cells from the first moment to the charging cut-off moment according to the current data and the voltage data, to obtain a plurality of charging capacities.

[0091] At the first moment, 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).

[0092] It can be understood that the first preset voltage is a preset value.

[0093] 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.

[0094] The charging capacity of the battery cell from the first moment to the charging cut-off moment can be calculated according to the ampere-hour method, and the formula for the charging capacity is:

[0095]

[0096] Among them, the Q CellChg2(i) is the charge amount of the ith cell from the first moment to the charging cut-off moment, t2 is the charging cut-off moment, and t 1Cell(i) is the first moment of the i-th battery cell, I(t) is the current during the charging process, and t is the time.

[0097] It can be understood that the number of the multiple charging quantities is the same as the number of the battery cells, and one battery cell corresponds to one charging quantity.

[0098] Step S302, obtaining a maximum value among the multiple charging capacities as a charging maximum value, and the chargeable capacity is a difference between the charging maximum value and the charging capacities.

[0099] After obtaining multiple charging capacities, the maximum value of the multiple charging capacities can be obtained by comparison and used as the charging maximum value. Then, the chargeable capacity of the battery cell can be obtained according to the difference between the charging capacity of a single battery cell and the charging maximum value.

[0100] It is worth noting that, in some embodiments, the total charge capacity can be calculated based on the rechargeable capacity. Specifically, the first charge capacity of the battery cell from the start of charging to the first moment can be calculated based on the current data and the voltage data, and the total charge capacity is the sum of the first charge capacity and the charge capacity.

[0101] The first charging capacity can be calculated according to the ampere-hour method, and the formula for the first charging capacity is:

[0102]

[0103] Among them, the Q CellChg1 (i) is the first charging capacity of the ith battery cell from the charging start time to the first time, t0 is the charging start time, and t 1Cell(i) is the first moment of the i-th battery cell, I(t) is the current during the charging process, and t is the time.

[0104] To facilitate readers to understand the above first preset voltage, chargeable capacity, first charge capacity, maximum charge capacity, and total charge capacity, an example is given below. Figure 6 , Figure 6 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 6 The first preset voltage, chargeable capacity, first charge capacity, maximum charge capacity, and total charge capacity of the battery cell during the charging process are illustrated. Figure 6 Cell1 to cell6 represent the first to sixth cells. Figure 6Vref in represents the first preset voltage, Figure 6 The charging end in represents the charging cut-off time, Figure 6 Q-CellChg1(2) in the figure represents the first charging capacity of the second cell. Figure 6 Q-PlusCellChg(2) in the figure represents the chargeable capacity of the second cell. Figure 6 Q-CellChg2(2) in the figure represents the charging capacity of the second cell. Figure 6 Q-MaxCellChg in represents the maximum charge value, Figure 6 Q-ComCellChg in the figure is the total charging capacity of the cell corresponding to the maximum charging value.

[0105] Step S40, calculating the dischargeable capacity of the battery cell at the discharge cut-off time according to the current data and the voltage data.

[0106] Due to the inconsistency of each of the battery cells, not all of the battery cells reach the discharge cut-off voltage when the discharge cut-off time is reached, that is, at the discharge cut-off time, the dischargeable amount is the amount of electricity that the battery cell can actually discharge when the battery is stopped from being discharged.

[0107] It is worth noting that, in some embodiments, see Figure 5 , Figure 5 4 is a flow chart of calculating the dischargeable capacity of a battery cell at the discharge cut-off time provided by an embodiment of the present application, that is, step S40 includes:

[0108] Step S401, calculating the discharge capacity of each of the battery cells from the second moment to the discharge cut-off moment according to the current data and the voltage data, to obtain a plurality of discharge capacities.

[0109] Wherein, at the second moment, 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 discharge cut-off voltage. For example: the voltage range of the battery cell is usually 1.2V-4.2V, then the second preset voltage can be set to 2.0V).

[0110] It can be understood that the second preset voltage is a preset value.

[0111] 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.

[0112] The discharge capacity of the battery cell from the second moment to the discharge cut-off moment can be calculated according to the ampere-hour method, and the formula for the discharge capacity is:

[0113]

[0114] Among them, the Q CellDischg2 (i) is the discharge capacity of the ith cell from the second moment to the discharge cut-off moment, t3 is the discharge cut-off moment, and t 2Cell(i) is the second moment of the ith battery cell, I(t) is the current during the discharge process, and t is the time.

[0115] It can be understood that the number of the multiple discharge quantities is the same as the number of the battery cells, and one battery cell corresponds to one discharge quantity.

[0116] Step S402, obtaining a maximum value among the multiple discharge capacities as the discharge maximum value, and the dischargeable capacity is a difference between the discharge maximum value and the discharge capacities.

[0117] After obtaining 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 dischargeable capacity of the battery cell can be obtained according to the difference between the discharge capacity of a single battery cell and the discharge maximum value.

[0118] It is worth noting that, in some embodiments, the total discharge capacity can be calculated based on the dischargeable capacity. Specifically, the first discharge capacity of the battery cell from the start of discharge to the second moment can be calculated based on the current data and the voltage data, and the total discharge capacity is the sum of the first discharge capacity and the discharge capacity.

[0119] The first discharge capacity can be calculated according to the ampere-hour method, and the formula for the first discharge capacity is:

[0120]

[0121] Among them, the Q CellDischg1 (i) is the first discharge capacity of the ith cell from the start of discharge to the second time, and t 100 is the discharge start time, and t 2Cell(i) is the second moment of the ith battery cell, I(t) is the current during the discharge process, and t is the time.

[0122] To facilitate readers to understand the above second preset voltage, dischargeable capacity, first discharge capacity, maximum discharge capacity, and total discharge capacity, examples are given below. Figure 7 , Figure 7 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, Figure 7The second preset voltage, dischargeable capacity, first discharge capacity, maximum discharge capacity, and total discharge capacity of the battery cell during the discharge process are illustrated. Figure 7 Cell1 to cell6 represent the first to sixth cells. Figure 7 Vref in denoted by the second preset voltage, Figure 7 The discharge end in represents the discharge cut-off time, Figure 7 Q—CellDischg1(5) in FIG. 5 represents the first discharge capacity of the fifth cell. Figure 7 Q—PlusCellDischg(5) in the figure represents the dischargeable capacity of the fifth cell. Figure 7 Q—CellDischg2(5) in FIG. 1 represents the discharge capacity of the fifth cell. Figure 7 Q-MaxCellDischg in represents the maximum discharge value, Figure 7 Q—ComCellDischg is the total discharge capacity of the cell corresponding to the maximum discharge value.

[0123] Step S50, obtaining the charge and discharge efficiency of the battery cell during the full charge and discharge process.

[0124] The obtaining of the charge and discharge efficiency of the battery cell during the full charge and discharge process may be obtaining the charge and discharge efficiency of the battery cell during the last full charge and discharge process. The last time refers to the current state of the battery cell, that is, when calculating the actual capacity of the battery cell, the charge and discharge efficiency of the battery cell during the last full charge and discharge process.

[0125] It is worth noting that, in some embodiments, see Figure 8 , Figure 8 is a schematic diagram of a flow chart for calculating the charge and discharge efficiency provided in an embodiment of the present application, that is, step S50 includes:

[0126] Step S501, obtaining the previous current data and the previous voltage data of the battery cell during the last full charge and discharge process.

[0127] Among them, the previous current data includes data related to the current of the battery cell during the last full charging process, and data related to the current of the battery cell during the last full discharging process. For details, please refer to the description of the current data in the above step S10, which will not be repeated here.

[0128] Among them, the previous voltage data includes data related to the voltage of the battery cell during the last full charging process, and data related to the voltage of the battery cell during the last full discharging process. For details, please refer to the description of the voltage data in the above step S10, which will not be repeated here.

[0129] Step S502, calculating the total fully charged power and the total fully discharged power of the battery cell according to the previous current data and the previous voltage data.

[0130] The total charging capacity of the full charge is the accumulated capacity of the battery cell during the last full charge process. Specifically, reference may be made to the calculation method of the total charging capacity of the battery cell in the above steps S20 and S30, which will not be repeated here.

[0131] The total discharge capacity of the battery cell is the capacity discharged by the battery cell during the last full discharge process. For details, reference may be made to the calculation method of the total discharge capacity of the battery cell in the above steps S20 and S40, which will not be repeated here.

[0132] Step S503, calculating the charge and discharge efficiency of the battery cell according to the total charge capacity of the full charge and the total discharge capacity of the full discharge.

[0133] In some embodiments, the formula for calculating the charge and discharge efficiency of the battery cell according to the full charge total power and the full discharge total power is:

[0134]

[0135] Wherein, η is the charge and discharge efficiency, Q FComCellDischg (i) is the total discharge capacity of the ith battery cell, and Q FComCellChg (i) is the total charging capacity of the i-th battery cell.

[0136] It is worth noting that the method for obtaining the charge and discharge efficiency of the battery cell during the full charge and discharge process is not limited to the above-mentioned steps S501 to S503, and there may be other methods. For example, for all the full charge and discharge processes performed on the battery cell, for any full charge and discharge process, the charge and discharge efficiency of the battery cell is obtained, and multiple charge and discharge efficiencies are obtained. The average value of the multiple charge and discharge efficiencies is calculated to obtain the charge and discharge efficiency of the battery cell during the full charge and discharge process.

[0137] Among them, for any full charging and discharging process, the method for obtaining the charging and discharging efficiency of the battery cell can refer to step S501 to step S503, which will not be repeated here.

[0138] Step S60, calculating the actual capacity of the battery cell according to the total charged capacity, the total discharged capacity, the chargeable capacity, the dischargeable capacity, and the charge and discharge efficiency.

[0139] In some embodiments, the formula for calculating the actual capacity of the battery cell according to the total charged capacity, the total discharged capacity, the chargeable capacity, the dischargeable capacity, and the charge and discharge efficiency is:

[0140]

[0141] Among them, the Q CellMark (i) is the actual capacity of the ith battery cell, and Q ComCellChg (i) is the total charge capacity of the ith battery cell, and Q ComCellDischg (i) is the total discharge capacity of the ith battery cell, and Q OkusCellChg (i) is the chargeable capacity of the ith battery cell, and Q PlusCellDischg (i) is the dischargeable capacity of the i-th battery cell, and η is the charge and discharge efficiency.

[0142] In an embodiment of the present application, the calculation method of the actual capacity of the battery cell includes obtaining the current data and voltage data of the battery cell during the charging and discharging process; calculating the total charging capacity and total discharging capacity of the battery cell according to the current data and voltage data; calculating the chargeable capacity of the battery cell at the charging cut-off time according to the current data and voltage data; calculating the dischargeable capacity of the battery cell at the discharge cut-off time according to the current data and voltage data; obtaining the charging and discharging efficiency of the battery cell during the full charging and discharging process; and calculating the actual capacity of the battery cell according to the total charging capacity, total discharging capacity, chargeable capacity, dischargeable capacity, and charging and discharging efficiency. The present application starts from the actual charging and discharging behavior of the battery cell, and after accurately calculating the total charging capacity and total discharging capacity, accurately calculating the chargeable capacity of the battery cell at the charging cut-off time, accurately calculating the dischargeable capacity of the battery cell at the discharge cut-off time, and combining the charging and discharging efficiency of the battery cell, the actual capacity of the battery cell is accurately determined. This series of steps constitutes a complete actual capacity calculation process, and the actual capacity calculation method accurately determines the actual capacity of a single battery cell.

[0143] Embodiment 4

[0144] The following is a discussion of the calculation method of the SOH of the battery cell provided in the embodiment of the present application. The SOH (State of Health) of the battery cell is an important parameter for measuring the performance and reliability of the battery cell. It reflects the aging and degradation of the battery cell with the increase of time and number of uses. The SOH of the battery cell is positively correlated with the actual capacity of the battery cell.

[0145] See also Fig. 9 , Fig. 9 : is a flow chart of a method for calculating the SOH of a battery cell provided in an embodiment of the present application, the method comprising the following steps:

[0146] Step S100, obtaining the actual capacity of the battery cell.

[0147] Wherein, the actual capacity is obtained by the calculation method of the actual capacity of the battery cell as mentioned above.

[0148] Step S200, obtaining the rated capacity of the battery cell.

[0149] The rated capacity of the battery cell is the minimum amount of electricity that the battery cell can output under a certain current, and the unit is mAh or Ah. Generally, the rated capacity of the battery cell is stored in the battery before leaving the factory.

[0150] Step S300, calculating the SOH of the battery cell according to the actual capacity and the rated capacity.

[0151] In some embodiments, the formula for calculating the SOH of the battery cell based on the actual capacity and the rated capacity is:

[0152]

[0153] Wherein, the SOH(i) is the SOH of the ith cell, and the Q CellMark (i) is the actual capacity of the ith battery cell, and Q CellRate is the rated capacity of the battery cell.

[0154] In some embodiments, the SOH(i) is displayed as a value less than 100, which reflects the health status of the battery cell. Fig.10 As shown, Fig.10 The SOH values ​​of six different cells are shown. Fig.10 Cell1 to cell6 represent the first to sixth battery cells.

[0155] In the embodiment of the present application, the calculation method of the SOH of the battery cell includes obtaining the actual capacity of the battery cell, wherein the actual capacity is obtained as the calculation method of the actual capacity of the battery cell described above; obtaining the rated capacity of the battery cell; and calculating the SOH of the battery cell according to the actual capacity and the rated capacity. That is, the SOH of the battery cell can be obtained in combination with the rated capacity of the battery cell, thereby fully reflecting the health status of the battery cell, enhancing the monitoring capability of the battery performance, helping to extend the service life of the battery and better realize battery management, optimizing the use efficiency of the battery, and ensuring the safe operation of the battery.

[0156] Embodiment 5

[0157] The following is a discussion of a method for calculating the SOC of a battery cell provided in an embodiment of the present application. The SOC (State of Charge) of a battery cell is an indicator that describes the current remaining power of the battery cell.

[0158] The calculation formula of SOC ampere-hour integral is as follows:

[0159]

[0160] SOC0 is the initial charge value of the battery state of charge. t-1 is the state of charge of the battery at time t-1, C is the actual total capacity of the battery; I(t) is the charge and discharge current of the battery at time t; t is the charge and discharge time.

[0161] According to the actual capacity of a single battery cell obtained in Example 3 and the above SOC ampere-hour integral calculation formula, the SOC of each battery cell can be obtained.

[0162] See also Fig.11 , Fig.11 : is a flow chart of a method for calculating the SOC of a battery cell provided in an embodiment of the present application, the method comprising the following steps:

[0163] Step 1000, obtaining the actual capacity of the battery cell.

[0164] Wherein, the actual capacity is obtained by the calculation method of the actual capacity of the battery cell as mentioned above.

[0165] Step 2000, calculating the cumulative power of the battery cell from the last SOC calculation time to the current time.

[0166] The current moment is the moment when the SOC of the battery cell is calculated this time, and the accumulated power can be calculated according to the ampere-hour method. The formula for calculating the accumulated power of the battery cell from the last SOC calculation moment to the current moment is:

[0167]

[0168] Among them, the Q CelAccumulate (i) is the accumulated power of the i-th battery cell, t1 is the last SOC calculation time, t2 is the current time, and I(t) is the current during the charging and discharging process.

[0169] Step 3000, obtaining the last SOC of the battery cell at the time of the last SOC calculation.

[0170] Step 4000, calculating the SOC of the battery cell at the current moment according to the accumulated power, the last SOC, and the actual capacity.

[0171] In some embodiments, the formula for calculating the SOC of the battery cell according to the accumulated power, the remaining dischargeable capacity, and the actual capacity is:

[0172]

[0173] Wherein, the SOC(i) t is the SOC of the ith cell at the current moment, SOC(i) t-1 is the SOC of the ith cell at the last SOC calculation time, the Q CelAccumulate (i) is the accumulated power of the ith battery cell, and Q CellMark (i) is the actual capacity of the ith battery cell.

[0174] In the embodiment of the present application, the method for calculating the SOC of the battery cell includes obtaining the actual capacity of the battery cell, wherein the actual capacity is obtained by the method for calculating the actual capacity of the battery cell as described above; calculating the cumulative power of the battery cell from the start of charging to the current moment; obtaining the last SOC of the battery cell at the time of the last SOC calculation; and calculating the SOC of the battery cell at the current moment based on the cumulative power, the last SOC, and the actual capacity. That is, by combining the cumulative power of the battery cell at the current moment, the last SOC, and the actual capacity of the battery cell, the SOC of the battery cell at the current moment can be obtained, which helps to optimize the management of the battery, improve energy efficiency, and help to understand the battery performance and control the battery.

[0175] Embodiment 6

[0176] The following is a discussion of the calculation device for the actual capacity of the battery cell provided in the embodiment of the present application. Fig.12 , Fig.12 It is a schematic diagram of a device for calculating the actual capacity of a battery cell provided in an embodiment of the present application, wherein the device 1 for calculating the actual capacity of a battery cell comprises a first acquisition module 11, for acquiring current data and voltage data of the battery cell during charging and discharging; a first calculation module 12, for calculating the total charging capacity and the total discharging capacity of the battery cell according to the current data and the voltage data; a second calculation module 13, for calculating the chargeable capacity of the battery cell at the charging cut-off time according to the current data and the voltage data; a third calculation module 14, for calculating the dischargeable capacity of the battery cell at the discharging cut-off time according to the current data and the voltage data; a second acquisition module 15, for acquiring the charge and discharge efficiency of the battery cell during full charging and discharging; and a fourth calculation module 16, for calculating the actual capacity of the battery cell according to the total charging capacity, the total discharging capacity, the chargeable capacity, the dischargeable capacity, and the charge and discharge efficiency.

[0177] In some embodiments, the second calculation module 13 includes a first calculation unit 131, which is used to calculate the charging capacity of each of the battery cells from the first moment to the charging cut-off moment according to the current data and the voltage data, and obtain multiple charging capacities, wherein at the first moment, 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 charging cut-off voltage; a first acquisition unit 132, which is used to obtain the maximum value of the multiple charging capacities as the charging maximum value, and the chargeable capacity is the difference between the charging maximum value and the charging capacity.

[0178] In some embodiments, the third calculation module 14 includes a second calculation unit 141, which is used to calculate the discharge capacity of each of the battery cells from the second moment to the discharge cut-off moment according to the current data and the voltage data, and obtain multiple discharge capacities, wherein at the second moment, 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; a second acquisition unit 142, which is used to obtain the maximum value of the multiple discharge capacities as the discharge maximum value, and the dischargeable capacity is the difference between the discharge maximum value and the discharge capacity.

[0179] In some embodiments, the first calculation module 12 is specifically used to calculate the first charge capacity of the battery cell from the charging start time to the first time according to the current data and the voltage data, and the total charge capacity is the sum of the first charge capacity and the charge capacity. The first calculation module 12 is also specifically used to calculate the first discharge capacity of the battery cell from the discharge start time to the second time according to the current data and the voltage data, and the total discharge capacity is the sum of the first discharge capacity and the discharge capacity.

[0180] In some embodiments, the second acquisition module 15 includes a third acquisition unit 151, which is used to obtain the previous current data and the previous voltage data of the battery cell during the last full charging and discharging process; a third calculation unit 152, which is used to calculate the total charging capacity of the battery cell and the total discharging capacity of the battery cell according to the previous current data and the previous voltage data; and a fourth calculation unit 153, which is used to calculate the charging and discharging efficiency of the battery cell according to the total charging capacity of the battery cell and the total discharging capacity of the battery cell.

[0181] In the embodiment of the present application, the current data and voltage data of the battery cell during the charging and discharging process are acquired through the first acquisition module 11; the total charging capacity and the total discharging capacity of the battery cell are calculated according to the current data and the voltage data through the first calculation module 12; the chargeable capacity of the battery cell at the charging cut-off time is calculated according to the current data and the voltage data through the second calculation module 13; the dischargeable capacity of the battery cell at the discharging cut-off time is calculated according to the current data and the voltage data through the third calculation module 14; the charging and discharging efficiency of the battery cell during the full charging and discharging process is acquired through the second acquisition module 15; the actual capacity of the battery cell is calculated according to the total charging capacity, the total discharging capacity, the chargeable capacity, the dischargeable capacity, and the charging and discharging efficiency through the fourth calculation module 16. That is, the present application starts from the actual charging and discharging behavior of the battery cell, and through accurate calculation of the total charging capacity and the total discharging capacity, through accurate calculation of the chargeable capacity of the battery cell at the charging cut-off time, through accurate calculation of the dischargeable capacity of the battery cell at the discharging cut-off time, and combined with the charging and discharging efficiency of the battery cell, the actual capacity of the battery cell is accurately determined. This series of steps constitutes a complete actual capacity calculation process, and the actual capacity calculation method accurately determines the actual capacity of a single battery cell.

[0182] Embodiment 7

[0183] The following is a discussion of the calculation device of the SOH of the battery cell provided in the embodiment of the present application. Fig.13 , Fig.13 It is a schematic diagram of a calculation device for the SOH of a battery cell provided in an embodiment of the present application. The calculation device 2 for the SOH of a battery cell includes a third acquisition module 21, which is used to obtain the actual capacity of the battery cell, wherein the actual capacity is obtained by the calculation method of the actual capacity of the battery cell as described above; a fourth acquisition module 22, which is used to obtain the rated capacity of the battery cell, wherein the rated capacity of the battery cell is the minimum amount of electricity that the battery cell can output under a certain current, and the unit is mAh or Ah. Generally, the rated capacity of the battery cell is stored in the battery before leaving the factory; a fifth calculation module 23, which is used to calculate the SOH of the battery cell based on the actual capacity and the rated capacity.

[0184] In the embodiment of the present application, the actual capacity of the battery cell is obtained by the third acquisition module 21, wherein the actual capacity is obtained by the calculation method of the actual capacity of the battery cell as described above; the rated capacity of the battery cell is obtained by the fourth acquisition module 22, wherein the rated capacity of the battery cell is the minimum amount of electricity that the battery cell can output under a certain current, and the unit is mAh or Ah. Generally, the rated capacity of the battery cell is stored in the battery before it leaves the factory; the SOH of the battery cell is calculated according to the actual capacity and the rated capacity by the fifth calculation module 23. That is, in combination with the rated capacity of the battery cell, the SOH of the battery cell can be obtained, so that the health status of the battery cell can be fully reflected, the monitoring capability of the battery performance can be enhanced, and it is helpful to extend the service life of the battery and better realize battery management, optimize the use efficiency of the battery, and ensure the safe operation of the battery.

[0185] Embodiment 8

[0186] The following is a discussion of the SOC calculation device of the battery cell provided in the embodiment of the present application. Fig.14 , Fig.14 It is a schematic diagram of a calculation device for the SOC of a battery cell provided in an embodiment of the present application, wherein the calculation device 3 for the SOC of a battery cell comprises a third acquisition module 31, for acquiring the actual capacity of the battery cell, and the actual capacity is obtained by the calculation method of the actual capacity of the battery cell as described above; a sixth calculation module 32, for calculating the cumulative power of the battery cell from the start of charging to the current moment; a fourth acquisition module 33, for acquiring the last SOC of the battery cell at the time of the last SOC calculation; and a seventh calculation module 34, for calculating the SOC of the battery cell at the current moment based on the cumulative power, the last SOC and the actual capacity.

[0187] It is worth noting that the third acquisition module 31 in the eighth embodiment has the same function as the third acquisition module 21 in the seventh embodiment. The third acquisition module 31 and the third acquisition module 21 can be the same module or two different modules.

[0188] In the embodiment of the present application, the actual capacity of the battery cell is obtained by the third acquisition module 31, and the actual capacity is obtained by the calculation method of the actual capacity of the battery cell as described above; the accumulated power of the battery cell from the start of charging to the current moment is calculated by the sixth calculation module 32; the last SOC of the battery cell at the last SOC calculation moment is obtained by the fourth acquisition module 33; and the SOC of the battery cell at the current moment is calculated by the seventh calculation module 34 according to the accumulated power, the last SOC, and the actual capacity. That is, by combining the accumulated power of the battery cell at the current moment, the last SOC, and the actual capacity of the battery cell, the SOC of the battery cell at the current moment can be obtained, which is helpful to optimize the management of the battery, improve energy utilization efficiency, and help understand the battery performance and control the battery.

[0189] 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 actual capacity of a battery cell, characterized in that: Applied to a battery, the battery includes a plurality of battery cells, and the method includes: Acquiring current data and voltage data of the battery cell during charging and discharging; Calculating the total charge quantity and the total discharge quantity of the battery cell according to the current data and the voltage data; Calculating the chargeable capacity of the battery cell at the charging cut-off time according to the current data and the voltage data; Calculating the dischargeable capacity of the battery cell at the discharge cut-off time according to the current data and the voltage data; Obtaining the charge and discharge efficiency of the battery cell during the full charge and discharge process; The actual capacity of the battery cell is calculated according to the total charged capacity, the total discharged capacity, the chargeable capacity, the dischargeable capacity, and the charge and discharge efficiency.

2. The method according to claim 1, characterized in that The step of calculating the chargeable amount of the battery cell at the 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 charge capacity of each of the battery cells from the first moment to the charge cut-off moment to obtain a plurality of charge capacities, wherein at the first moment, 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 maximum value among the multiple charging power amounts is obtained as a charging maximum value, and the chargeable amount is a difference between the charging maximum value and the charging power amount.

3. The method according to claim 2, characterized in that The step of calculating the dischargeable amount of the battery cell at the discharge cut-off time according to the current data and the voltage data comprises: According to the current data and the voltage data, the discharge capacity of each of the battery cells from the second moment to the discharge cut-off moment is calculated respectively to obtain a plurality of discharge capacities, wherein at the second moment, 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; A maximum value among the multiple discharge quantities is obtained as the discharge maximum value, and the dischargeable quantity is the difference between the discharge maximum value and the discharge quantity.

4. The method according to claim 3, characterized in that The step of calculating the total charge quantity and the total discharge quantity of the battery cell according to the current data and the voltage data comprises: Calculate, based on the current data and the voltage data, a first charging quantity of the battery cell from a charging start time to the first time, wherein the total charging quantity is the sum of the first charging quantity and the charging quantity; The first discharge capacity of the battery cell from the start of discharge to the second time is calculated according to the current data and the voltage data, and the total discharge capacity is the sum of the first discharge capacity and the discharge capacity.

5. The method according to any one of claims 1 to 4, characterized in that: The step of obtaining the charge and discharge efficiency of the battery cell during the full charge and discharge process comprises: Acquire the previous current data and the previous voltage data of the battery cell during the last full charge and discharge process; Calculating the total charge capacity of the battery cell and the total discharge capacity of the battery cell according to the previous current data and the previous voltage data; The charge and discharge efficiency of the battery cell is calculated according to the total charge capacity of the full charge and the total discharge capacity of the full discharge.

6. The method according to claim 5, characterized in that The formula for calculating the charge and discharge efficiency of the battery cell according to the total charge capacity of the full charge and the total discharge capacity of the full discharge is: Wherein, η is the charge and discharge efficiency, Q FComCellDischg (i) is the total discharge capacity of the ith battery cell, and Q FComCellChg (i) is the total charging capacity of the i-th battery cell.

7. The method according to claim 1, characterized in that The formula for calculating the actual capacity of the battery cell according to the total charged capacity, total discharged capacity, chargeable capacity, dischargeable capacity, and charge and discharge efficiency is: Among them, the Q CellMark (i) is the actual capacity of the ith battery cell, and Q ComCellChg (i) is the total charge capacity of the ith battery cell, and Q ComCellDischg (i) is the total discharge capacity of the ith battery cell, and Q PlusCellChg (i) is the chargeable capacity of the ith battery cell, and Q PlusCellDischg (i) is the dischargeable capacity of the i-th battery cell, and η is the charge and discharge efficiency.

8. A method for calculating the SOH of a battery cell, characterized in that: Applied to a battery, the battery includes a plurality of battery cells, and the method includes: Obtaining the actual capacity calculated by the method according to any one of claims 1 to 7; Obtaining the rated capacity of the battery cell; The SOH of the battery cell is calculated according to the actual capacity and the rated capacity.

9. A method for calculating the SOC of a battery cell, characterized in that: Applied to a battery, the battery includes a plurality of battery cells, and the method includes: Obtaining the actual capacity calculated by the method according to any one of claims 1 to 7; Calculate the cumulative power of the battery cell from the last SOC calculation time to the current time; Obtain the last SOC of the battery cell at the last SOC calculation time; The SOC of the battery cell at the current moment is calculated according to the accumulated power, the previous SOC, and the actual capacity.

10. The method according to claim 9, characterized in that The formula for calculating the SOC of the battery cell according to the accumulated power, the last SOC, and the actual capacity is: Among them, SOC(i) t is the SOC of the ith cell at the current time (time t), SOC(i) t-1 is the SOC of the ith cell at the start of charging or discharging (time t-1), Q CellAccumualte (i) is the cumulative power of the ith battery cell, Q VellMark (i) is the actual capacity of the ith battery cell.

11. A device for calculating the actual capacity of a battery cell, characterized in that: Applied to a battery, the battery includes a plurality of cells, and the device includes: A first acquisition module, used to acquire current data and voltage data of the battery cell during charging and discharging; A first calculation module, used for calculating the total charge power and the total discharge power of the battery cell according to the current data and the voltage data; A second calculation module, used to calculate the chargeable amount of the battery cell at the charging cut-off time according to the current data and the voltage data; A third calculation module, used to calculate the dischargeable amount of the battery cell at the discharge cut-off time according to the current data and the voltage data; A second acquisition module is used to obtain the charge and discharge efficiency of the battery cell during a full charge and discharge process; The fourth calculation module is used to calculate the actual capacity of the battery cell according to the total charged power, the total discharged power, the chargeable capacity, the dischargeable capacity, and the charge and discharge efficiency.

12. A device for calculating the SOH of a battery cell, characterized in that: Applied to a battery, the battery includes a plurality of cells, and the device includes: A third acquisition module, configured to acquire the actual capacity calculated by the method according to any one of claims 1 to 7; A fourth acquisition module, used to acquire the rated capacity of the battery cell; The fifth calculation module is used to calculate the SOH of the battery cell according to the actual capacity and the rated capacity.

13. A device for calculating the SOC of a battery cell, characterized in that: Applied to a battery, the battery includes a plurality of cells, and the device includes: A third acquisition module, configured to acquire the actual capacity calculated by the method according to any one of claims 1 to 7; A sixth calculation module, used to calculate the cumulative power of the battery cell from the last SOC calculation time to the current time; A fourth acquisition module, used to acquire the last SOC of the battery cell at the last SOC calculation moment; The seventh calculation module is used to calculate the SOC of the battery cell according to the accumulated power, the last SOC, and the actual capacity.

14. 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.

15. 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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