Method, device, electronic device and medium for estimating energy state of battery system

Abstract

The present invention relates to the field of lithium-ion battery management technology, and more specifically, to a method, device, electronic device and medium for estimating the energy state of a battery system. The method obtains the current battery power state of each battery cell, the current actual capacity value of each battery cell and the cut-off battery power state of each battery cell; and can obtain the reference battery power that needs to be discharged based on the current battery power state of each battery cell, the cut-off battery power state and the current actual capacity value; and then can obtain the energy state of the battery system based on the reference battery power that needs to be discharged, the current actual capacity value of each battery cell and the corresponding relationship between the open circuit voltage of each battery cell and the battery power state. The method successfully solves the complexity problem of system energy estimation after battery cells are grouped, and can cope with the energy state estimation in a battery system composed of multiple battery cells connected in series or in parallel.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium-ion battery management, and in particular to a method, device, electronic equipment and medium for estimating the energy state of a battery system. Background Art

[0002] Lithium-ion batteries have the advantages of high energy density, long cycle life, light weight, fast charging and low self-discharge rate, which makes them the preferred energy storage solution in many fields. In the field of electric vehicles, including electric vehicles, hybrid vehicles and electric bicycles, lithium batteries are widely used to reduce exhaust emissions and promote the sustainable development of transportation. In addition, lithium batteries also play an important role in portable electronic devices, renewable energy storage, emergency power backup, aerospace, power systems and other fields.

[0003] The energy state of a battery system refers to the amount of electrical energy remaining in the battery system at the current moment, measured in kilowatt-hours (kWh). Accurate and real-time estimation of the energy state of a battery system is critical to its safe and efficient application. For example, in electric vehicles, accurate calculation of the remaining battery energy is required to estimate the remaining range of the electric vehicle; in large-scale battery energy storage systems on the grid side, real-time knowledge of the remaining available battery energy can better provide a basis for grid dispatching, in order to carry out peak shaving and valley filling, and new energy consumption.

[0004] Existing methods mainly focus on estimating the energy state of a single battery cell. There are also great challenges in estimating the energy state of a single battery cell. When multiple battery cells are grouped, the problem will be further complicated. This is mainly reflected in the fact that after the battery system has been running for a long time, the inconsistency between the battery cells will increase significantly, mainly manifested in the inconsistency of the charge and capacity between the batteries, which will make the accurate energy state estimation of the battery system more challenging. Summary of the invention

[0005] The present invention provides a method, device, electronic device and medium for estimating the energy state of a battery system, which can overcome certain defects of the prior art.

[0006] The method for estimating the energy state of a lithium-ion battery system according to the present invention comprises:

[0007] Obtain the current battery power status of each battery cell; wherein the battery power status is the percentage of the ratio of the remaining power of the battery cell to the rated capacity of the battery cell;

[0008] Get the current actual capacity value of each battery cell;

[0009] Obtaining a cut-off battery power state of each battery cell; wherein the cut-off battery power state is a preset value, and when the battery power state of the battery cell reaches the cut-off battery power state, the battery cell stops discharging;

[0010] Obtaining a reference battery power to be discharged based on the current battery power state, the cut-off battery power state and the current actual capacity value of each battery cell; wherein the reference battery power to be discharged is the battery power that needs to be discharged from each battery cell from the current state to when the battery system is in the cut-off discharge state;

[0011] The energy state of the battery system is obtained based on the corresponding relationship between the reference battery power that needs to be discharged, the current actual capacity value of each battery cell, and the open circuit voltage of each battery cell and the battery power state.

[0012] The above scheme successfully solves the complexity problem of system energy estimation after battery cells are grouped by introducing a total energy calculation method. It can cope with the energy state estimation in a battery system composed of multiple battery cells connected in series and parallel. By accurately estimating the total energy of the entire battery system, it provides a reliable reference for the actual energy output of the battery system.

[0013] Preferably, the step of obtaining the reference battery power to be discharged based on the current battery power state, the cut-off battery power state and the current actual capacity value of each battery cell includes:

[0014] Obtaining the battery power state difference that needs to be discharged for each battery cell based on the difference between the current battery power state and the cut-off battery power state, and obtaining the battery power that needs to be discharged for each battery cell based on the product of the battery power state difference and the current actual capacity value;

[0015] The minimum value of the battery power that needs to be discharged of each battery cell is used as the reference battery power that needs to be discharged.

[0016] Based on this, the inconsistency between battery cells can be fully considered. The above scheme effectively deals with the inconsistency of battery cells in the battery system group by calculating the difference between the current battery power state and the cutoff battery power state of each battery cell, and considering the capacity of different battery cells.

[0017] Preferably, the energy state of the battery system is obtained based on the correspondence between the reference battery power to be discharged, the current actual capacity value of each battery cell, and the open circuit voltage of each battery cell and the battery power state, including:

[0018] The battery power state of each battery cell when the battery system is in the cut-off discharge state is calculated based on the reference battery power to be discharged and the current actual capacity value;

[0019] The energy state of the battery system is obtained based on the battery power state of each battery cell when the battery system is in a cut-off discharge state and the corresponding relationship between the open circuit voltage of each battery cell and the battery power state.

[0020] Based on this, a relatively simple calculation method is used when calculating the energy state of the battery system, so that in the development process of the battery management system, more attention can be paid to the estimation of the current battery power state of the battery cell. In this way, the complexity of the overall system is simplified and the practicality and development efficiency of the system are improved.

[0021] Preferably, the method of calculating and obtaining the battery power state of each battery cell when the battery system is in the cut-off discharge state based on the reference battery power to be discharged and the current actual capacity value includes:

[0022] Obtaining the percentage of battery power discharged from each battery cell when the battery system is in a cut-off discharge state based on the ratio of the reference battery power to be discharged and the current actual capacity value;

[0023] Based on the current battery power state and the percentage of discharged battery power, the final battery power state of each battery cell when the battery system is in the cut-off discharge state is obtained; wherein the final battery power state is the battery power state when the battery system is in the cut-off discharge state.

[0024] Therefore, the final battery power state of each battery cell can be obtained relatively easily when the battery system is in the cut-off discharge state.

[0025] Preferably, the energy state of the battery system is obtained based on the battery power state of each battery cell when the battery system is in a cut-off discharge state and the corresponding relationship between the open circuit voltage of each battery cell and the battery power state, including:

[0026] The battery power of each battery cell in the current state is obtained by calculating the corresponding relationship between the current actual capacity value and the open circuit voltage and the battery power state;

[0027] The battery capacity of each battery cell when the battery system is in the cut-off discharge state is calculated based on the corresponding relationship between the current actual capacity value and the open circuit voltage and the battery capacity state;

[0028] The energy state of the battery system is obtained based on the difference between the battery power of each battery cell in the current state and the battery power when the battery system is in the cut-off discharge state.

[0029] Based on the above, it is possible to better realize the relatively simple acquisition of the energy state of the battery system.

[0030] Preferably, the battery capacity of the cell in any state is the product of the integral value obtained by integrating the correspondence between the open circuit voltage and the battery capacity state in the interval from 0 to the battery capacity state in the arbitrary state and the current actual capacity value. Therefore, the acquisition of relevant data can be achieved better.

[0031] A device for estimating the energy state of a lithium-ion battery system according to the present invention comprises:

[0032] A first acquisition unit is used to obtain the current battery power state of each battery cell; wherein the battery power state is the percentage of the ratio of the remaining power of the battery cell to the rated capacity of the battery cell;

[0033] The second acquisition unit is used to obtain the current actual capacity value of each battery cell;

[0034] A third acquisition unit is used to obtain a cut-off battery power state of each battery cell; wherein the cut-off battery power state is a preset value, and when the battery power state of the battery cell reaches the cut-off battery power state, the battery cell stops discharging;

[0035] A first calculation unit is used to obtain a reference battery power to be discharged based on the current battery power state, the cut-off battery power state and the current actual capacity value of each battery cell; wherein the reference battery power to be discharged is the battery power that needs to be discharged from each battery cell from the current state to when the battery system is in the cut-off discharge state; and

[0036] The second calculation unit is used to obtain the energy state of the battery system based on the corresponding relationship between the reference battery power that needs to be discharged, the current actual capacity value of each battery cell and the open circuit voltage of each battery cell and the battery power state.

[0037] An electronic device according to the present invention includes:

[0038] at least one processor; and

[0039] a memory communicatively connected to the at least one processor; wherein,

[0040] The memory stores instructions that can be executed by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform any of the above estimation methods.

[0041] According to a non-transitory computer-readable storage medium storing computer instructions of the present invention, the computer instructions are used to enable the computer to execute any of the above estimation methods.

[0042] A computer program product according to the present invention comprises a computer program, and when the computer program is executed by a processor, the computer program implements any of the above estimation methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 A schematic flow chart of a method for estimating the energy state of a lithium-ion battery system disclosed in a specific implementation;

[0044] Figure 2 A corresponding relationship between the open circuit voltage and the battery charge state in a method for estimating the energy state of a lithium-ion battery system disclosed in a specific implementation. DETAILED DESCRIPTION

[0045] In order to further understand the content of the present invention, the present invention is described in detail in conjunction with the embodiments. It should be understood that the embodiments are only for explaining the present invention and are not intended to limit it.

[0046] See Figure 1 In a specific embodiment of the present disclosure, a method for estimating the energy state of a lithium-ion battery system is provided; the method can ensure that even if a certain degree of inconsistency has appeared between the battery cells after the battery system has been running for a long time, the energy state of the entire battery system can still be accurately estimated.

[0047] In this specific embodiment, the provided estimation method includes:

[0048] Obtain the current battery power status of each battery cell; wherein the battery power status is the percentage of the ratio of the remaining power of the battery cell to the rated capacity of the battery cell;

[0049] Get the current actual capacity value of each battery cell;

[0050] Obtaining a cut-off battery power state of each battery cell; wherein the cut-off battery power state is a preset value, and when the battery power state of the battery cell reaches the cut-off battery power state, the battery cell stops discharging;

[0051] Obtaining a reference battery power to be discharged based on the current battery power state, the cut-off battery power state and the current actual capacity value of each battery cell; wherein the reference battery power to be discharged is the battery power that needs to be discharged from each battery cell from the current state to when the battery system is in the cut-off discharge state;

[0052] The energy state of the battery system is obtained based on the corresponding relationship between the reference battery power that needs to be discharged, the current actual capacity value of each battery cell, and the open circuit voltage of each battery cell and the battery power state.

[0053] The above scheme successfully solves the complexity problem of system energy estimation after battery cells are grouped by introducing a total energy calculation method. It can cope with the energy state estimation in a battery system composed of multiple battery cells connected in series and parallel. By accurately estimating the total energy of the entire battery system, it provides a reliable reference for the actual energy output of the battery system.

[0054] In another preferred embodiment, the method of obtaining the reference battery power to be discharged based on the current battery power state, the cut-off battery power state and the current actual capacity value of each battery cell can also include, for example:

[0055] Obtaining the battery power state difference that needs to be discharged for each battery cell based on the difference between the current battery power state and the cut-off battery power state, and obtaining the battery power that needs to be discharged for each battery cell based on the product of the battery power state difference and the current actual capacity value;

[0056] The minimum value of the battery power that needs to be discharged of each battery cell is used as the reference battery power that needs to be discharged.

[0057] Based on this, the inconsistency between battery cells can be fully considered. The above scheme effectively deals with the inconsistency of battery cells in the battery system group by calculating the difference between the current battery power state and the cutoff battery power state of each battery cell, and considering the capacity of different battery cells.

[0058] In another preferred embodiment, the energy state of the battery system is obtained based on the correspondence between the reference battery power to be discharged, the current actual capacity value of each battery cell and the open circuit voltage of each battery cell and the battery power state, and can also include, for example:

[0059] The battery power state of each battery cell when the battery system is in the cut-off discharge state is calculated based on the reference battery power to be discharged and the current actual capacity value;

[0060] The energy state of the battery system is obtained based on the battery power state of each battery cell when the battery system is in a cut-off discharge state and the corresponding relationship between the open circuit voltage of each battery cell and the battery power state.

[0061] Based on this, a relatively simple calculation method is used when calculating the energy state of the battery system, so that in the development process of the battery management system, more attention can be paid to the estimation of the current battery power state of the battery cell. In this way, the complexity of the overall system is simplified and the practicality and development efficiency of the system are improved.

[0062] As a preferred implementation of the further preferred embodiment, the method of calculating and obtaining the battery power state of each battery cell when the battery system is in the cut-off discharge state based on the reference battery power to be discharged and the current actual capacity value may also include, for example:

[0063] Obtaining the percentage of battery power discharged from each battery cell when the battery system is in a cut-off discharge state based on the ratio of the reference battery power to be discharged and the current actual capacity value;

[0064] Based on the current battery power state and the percentage of discharged battery power, the final battery power state of each battery cell when the battery system is in the cut-off discharge state is obtained; wherein the final battery power state is the battery power state when the battery system is in the cut-off discharge state.

[0065] Therefore, the final battery power state of each battery cell can be obtained relatively easily when the battery system is in the cut-off discharge state.

[0066] As another preferred implementation in the further preferred embodiment, the energy state of the battery system is obtained based on the battery power state of each battery cell when the battery system is in the cut-off discharge state and the corresponding relationship between the open circuit voltage of each battery cell and the battery power state, which can include, for example:

[0067] The battery power of each battery cell in the current state is obtained by calculating the corresponding relationship between the current actual capacity value and the open circuit voltage and the battery power state;

[0068] The battery capacity of each battery cell when the battery system is in the cut-off discharge state is calculated based on the corresponding relationship between the current actual capacity value and the open circuit voltage and the battery capacity state;

[0069] The energy state of the battery system is obtained based on the difference between the battery power of each battery cell in the current state and the battery power when the battery system is in the cut-off discharge state.

[0070] Based on the above, it is possible to better realize the relatively simple acquisition of the energy state of the battery system.

[0071] In addition, the battery capacity of the cell in any state is the product of the integral value obtained by integrating the correspondence between the open circuit voltage and the battery capacity state in the interval from 0 to the battery capacity state in the arbitrary state and the current actual capacity value. Therefore, the acquisition of relevant data can be achieved better.

[0072] In any of the above-mentioned specific implementations or preferred embodiments, the battery power state can be characterized by a parameter SOC (State of charge), the unit of the parameter SOC is a percentage, and can be estimated in real time by a battery management system (BMS) in the battery system. Since the SOC changes rapidly, an estimate update is usually required every second. The estimation method usually includes ampere-hour integration, Kalman filtering, etc., which are not discussed in detail in this disclosure.

[0073] In any of the above-mentioned specific implementations or preferred embodiments, the current actual capacity value Q, in units of Ah, can be estimated by a battery management system (BMS). Since the battery capacity value usually changes slowly and the update cycle of the capacity value is usually longer, the battery capacity value can be estimated by a sum least squares algorithm, a Kalman filter algorithm, etc., which will not be discussed in detail in this disclosure.

[0074] For battery safety reasons, the power of a single cell in a battery system is usually set to not be fully discharged, which will affect the cut-off battery power state SOC of each cell. min Preset (the preset values ​​of different cells in the same battery system can be the same or different), the battery state of charge SOC cutoff min Refers to the lowest battery state that a single cell can reach when discharged. For example, the discharge depth of industrial and commercial energy storage systems is deep, usually SOC min It can be set as low as 1%; in the field of pure electric vehicle applications, SOC min The setting is usually higher, for example, it can be set to 5%; this setting can effectively avoid over-discharge.

[0075] It can be understood that the current actual capacity value SOC of each battery cell is different from the battery power state SOC at the end. min The battery state difference SOC of each battery cell that needs to be discharged can be obtained by subtracting diff , i.e. SOC diff =SOC-SOC min .

[0076] In the present disclosure, the battery state difference SOC of each battery cell can be diff The difference between battery state of charge and SOC diff The product operation is performed to obtain the battery power required to be discharged for each battery cell; the reference battery power Qdis can be obtained by obtaining the minimum value of the battery power required to be discharged of all the battery cells, that is, Qdis = min (Q*SOC diff ). It is understood that in a battery system, when any cell reaches the cut-off battery state of charge SOC minThe entire battery system will stop discharging; that is, the reference battery capacity Qdis can represent the amount of electricity released by each cell when the battery system changes from the current state to a state where it has no discharge capability, in units of Ah.

[0077] It is understandable that due to factors such as production process, batch, and usage time, different cells in the same battery system will inevitably produce differences in the current actual capacity value, current battery power state, etc. in a certain state of the discharge process, and the cut-off battery power state of different cells can also be set to be different, which is the difference between different cells. This difference results in that when the battery system is in a state where it does not have the ability to discharge, the battery power state SOC of different cells when the battery system is in the cut-off discharge state is different. end In order to facilitate the next step of calculation, in the present disclosure, the battery state of charge SOC of each battery cell when the battery system is in the cut-off discharge state can be calculated. end Calculate and obtain; specifically, the battery power percentage SOC that needs to be discharged from each battery cell from the current state to the battery system being in the cut-off discharge state can be calculated based on the reference battery power Qdis and the current actual capacity value Q of each battery cell dis , i.e. SOC dis =Qdis / Q; then the battery power state SOC of each battery cell when the battery system is in the cut-off discharge state can be obtained end , i.e. SOC end =SOC-SOC dis Understandably, SOC end Indicates that a cell in the battery system reaches the corresponding cut-off SOC first min The power status of each battery cell in the battery system at this time.

[0078] In the present disclosure, when calculating the total energy of the entire battery system at the current moment (i.e., the energy state of the battery system), it can be achieved based on the curve function of SOC and open circuit voltage (i.e., the correspondence between the open circuit voltage and the battery power state). The correspondence between the open circuit voltage and the battery power state is usually obtained by offline testing during the development of the battery management system, and is not described in detail or specified in the present disclosure.

[0079] For a single battery cell, the energy E at any battery charge state battery The open circuit voltage of the battery cell is integrated and multiplied by its capacity Q, in units of Wh, that is,

[0080]

[0081] Therefore, for the battery system, the energy state TE in its current state is currentBased on the energy of all cells and summing them up, we can get:

[0082]

[0083] Q(k) represents the current actual capacity value of the k-th battery cell, and soc(k) represents the current battery power state of the k-th battery cell.

[0084] Similarly, the energy state TE of the battery system when it is discharged to the point where it has no discharge capacity end Based on the energy of all cells and summing them up, we can get:

[0085]

[0086] In the above, soc end (k) is the battery power state of the kth battery cell when the battery system is in the cut-off discharge state.

[0087] Obviously, the energy state TE based on the battery system is,

[0088] TE=TE current -TE end .

[0089] Right now,

[0090]

[0091] The estimation method of the present disclosure is described below with a more specific embodiment. In this more specific embodiment, the energy state of a one-parallel-five-series (1P5S) lithium iron phosphate battery system is estimated based on the above estimation method.

[0092] The lithium iron phosphate battery system has 5 battery cells connected in series. It can be understood that this is only an exemplary description. In actual applications, different numbers of battery packs can be built through series or parallel connections as needed. The discharge energy calculation method disclosed in the present invention is not limited by the specific number of series and parallel connections of the battery. The battery packs after series and parallel connection can still apply the same algorithm to calculate the discharge energy.

[0093] At the current moment,

[0094] The current actual capacity value SOC of each battery cell is 55%, 50%, 46%, 60%, and 57% respectively.

[0095] The current actual capacity value Q of each battery cell is 100Ah, 100Ah, 95Ah, 105Ah, and 100Ah respectively.

[0096] Each battery cell reaches the corresponding cut-off SOC min Battery state of charge SOCdiff They are 50%, 45%, 41%, 55% and 52% respectively;

[0097] Therefore, the reference battery capacity Qdis is, Qdis=min(100*50%, 100*45%, 95*41%, 105*55%, 100*52%)=38.95Ah.

[0098] The battery state of charge SOC of each battery cell when the battery system is in the cut-off discharge state end That is,

[0099] 55%-38.95 / 100=16.05%;

[0100] 50%-38.95 / 100=11.05%;

[0101] 46%-38.95 / 95=5%;

[0102] 60%-38.95 / 105=22.90%;

[0103] 57%-38.95 / 100=18.05%.

[0104] Obviously, at this time, the third battery cell has reached the cut-off battery power state of 5%, and the entire battery system cannot be discharged.

[0105] This lithium iron phosphate battery has the following features: Figure 2 The open circuit voltage corresponds to the battery charge state OCV(s) shown in the figure. The energy state TE of the battery system in the current state is:

[0106]

[0107] It is understandable that in this more specific embodiment, the capacities of the five lithium batteries used are set to be equal, and the rated capacity of each battery cell is 100Ah. However, in actual applications, there may be certain differences and deviations in the capacity of each battery cell in the battery pack. In this case, the above-mentioned discharge energy estimation method is also applicable. The battery management system will independently monitor and track the capacity of each battery cell in real time, and participate in the energy state estimation based on the actual capacity Q value of each battery cell obtained by monitoring. In this way, even if the capacities of different batteries in the battery pack are not completely equal, the available discharge energy of the entire battery system can be accurately calculated. The applicability of this calculation method is not affected by the uniformity of the battery cell capacity.

[0108] At the same time, an embodiment of the present disclosure also provides an energy state estimation device for a lithium-ion battery system, which includes:

[0109] A first acquisition unit is used to obtain the current battery power state of each battery cell; wherein the battery power state is the percentage of the ratio of the remaining power of the battery cell to the rated capacity of the battery cell;

[0110] The second acquisition unit is used to obtain the current actual capacity value of each battery cell;

[0111] A third acquisition unit is used to obtain a cut-off battery power state of each battery cell; wherein the cut-off battery power state is a preset value, and when the battery power state of the battery cell reaches the cut-off battery power state, the battery cell stops discharging;

[0112] A first calculation unit is used to obtain a reference battery power to be discharged based on the current battery power state, the cut-off battery power state and the current actual capacity value of each battery cell; wherein the reference battery power to be discharged is the battery power that needs to be discharged from each battery cell from the current state to when the battery system is in the cut-off discharge state; and

[0113] The second calculation unit is used to obtain the energy state of the battery system based on the corresponding relationship between the reference battery power that needs to be discharged, the current actual capacity value of each battery cell and the open circuit voltage of each battery cell and the battery power state.

[0114] At the same time, an embodiment of the present disclosure further provides an electronic device, including:

[0115] at least one processor; and

[0116] a memory communicatively connected to the at least one processor; wherein,

[0117] The memory stores instructions that can be executed by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform any of the above estimation methods.

[0118] At the same time, an embodiment of the present disclosure further provides a non-transitory computer-readable storage medium storing computer instructions, wherein the computer instructions are used to enable the computer to execute any of the above-mentioned estimation methods.

[0119] Meanwhile, an embodiment of the present disclosure further provides a computer program product, including a computer program, which implements any of the above estimation methods when executed by a processor.

[0120] It is easy to understand that those skilled in the art can combine, split, reorganize, etc. the embodiments of the present application to obtain other embodiments based on one or several embodiments provided in the present application, and these embodiments do not exceed the protection scope of the present application.

[0121] The present invention and its implementation methods are described schematically above, and the description is not restrictive. The embodiments shown in the embodiments are only part of the implementation methods of the present invention, and the actual structure is not limited thereto. Therefore, if a person skilled in the art is inspired by the embodiments and designs a structure and an implementation method similar to the technical solution without creativity without departing from the purpose of the invention, they should all fall within the protection scope of the present invention.

[0122] It should be noted that different types of batteries have different open circuit voltage characteristics. Batteries of the same type produced by different manufacturers also have different open circuit voltage characteristics. The open circuit voltage characteristics need to be obtained through designed experiments, but the method of calculating system energy itself is universal.

Claims

1. A method for estimating the energy state of a lithium-ion battery system, comprising: Obtain the current battery power status of each battery cell; wherein the battery power status is the percentage of the ratio of the remaining power of the battery cell to the rated capacity of the battery cell; Get the current actual capacity value of each battery cell; Obtaining a cut-off battery power state of each battery cell; wherein the cut-off battery power state is a preset value, and when the battery power state of the battery cell reaches the cut-off battery power state, the battery cell stops discharging; Obtaining a reference battery power to be discharged based on the current battery power state, the cut-off battery power state and the current actual capacity value of each battery cell; wherein the reference battery power to be discharged is the battery power that needs to be discharged from each battery cell from the current state to when the battery system is in the cut-off discharge state; Obtaining the energy state of the battery system based on the corresponding relationship between the reference battery power to be discharged, the current actual capacity value of each battery cell and the open circuit voltage of each battery cell and the battery power state; The method of obtaining the reference battery power to be discharged based on the current battery power state, the cut-off battery power state and the current actual capacity value of each battery cell includes: Obtaining the battery power state difference that needs to be discharged for each battery cell based on the difference between the current battery power state and the cut-off battery power state, and obtaining the battery power that needs to be discharged for each battery cell based on the product of the battery power state difference and the current actual capacity value; The minimum value of the battery power that needs to be discharged of each battery cell is used as the reference battery power that needs to be discharged; The energy state of the battery system is obtained based on the corresponding relationship between the reference battery power to be discharged, the current actual capacity value of each battery cell and the open circuit voltage of each battery cell and the battery power state, including: The battery power state of each battery cell when the battery system is in the cut-off discharge state is calculated based on the reference battery power to be discharged and the current actual capacity value; The energy state of the battery system is obtained based on the battery power state of each battery cell when the battery system is in a cut-off discharge state and the corresponding relationship between the open circuit voltage of each battery cell and the battery power state.

2. The estimation method according to claim 1, characterized in that The method of calculating and obtaining the battery power state of each battery cell when the battery system is in the cut-off discharge state based on the reference battery power to be discharged and the current actual capacity value includes: Obtaining the percentage of battery power discharged from each battery cell when the battery system is in a cut-off discharge state based on the ratio of the reference battery power to be discharged and the current actual capacity value; Based on the current battery power state and the percentage of discharged battery power, the final battery power state of each battery cell when the battery system is in the cut-off discharge state is obtained; wherein the final battery power state is the battery power state when the battery system is in the cut-off discharge state.

3. The estimation method according to claim 1, characterized in that The energy state of the battery system is obtained based on the battery power state of each battery cell when the battery system is in a cut-off discharge state and the corresponding relationship between the open circuit voltage of each battery cell and the battery power state, including: The battery power of each battery cell in the current state is obtained by calculating the corresponding relationship between the current actual capacity value and the open circuit voltage and the battery power state; The battery capacity of each battery cell when the battery system is in the cut-off discharge state is calculated based on the corresponding relationship between the current actual capacity value and the open circuit voltage and the battery capacity state; The energy state of the battery system is obtained based on the difference between the battery power of each battery cell in the current state and the battery power when the battery system is in the cut-off discharge state.

4. The estimation method according to claim 3, characterized in that: The battery capacity of the cell in any state is the product of an integral value obtained by integrating the correspondence between the open circuit voltage and the battery capacity state in the interval from 0 to the battery capacity state in the arbitrary state and the current actual capacity value.

5. A device for estimating the energy state of a lithium-ion battery system, comprising: A first acquisition unit is used to obtain the current battery power state of each battery cell; wherein the battery power state is the percentage of the ratio of the remaining power of the battery cell to the rated capacity of the battery cell; The second acquisition unit is used to obtain the current actual capacity value of each battery cell; A third acquisition unit is used to obtain a cut-off battery power state of each battery cell; wherein the cut-off battery power state is a preset value, and when the battery power state of the battery cell reaches the cut-off battery power state, the battery cell stops discharging; The first calculation unit is used to obtain a reference battery power to be discharged based on the current battery power state, the cut-off battery power state and the current actual capacity value of each battery cell, including: Obtaining the battery power state difference that needs to be discharged for each battery cell based on the difference between the current battery power state and the cut-off battery power state, and obtaining the battery power that needs to be discharged for each battery cell based on the product of the battery power state difference and the current actual capacity value; The minimum value of the battery power that needs to be discharged of each battery cell is used as the reference battery power that needs to be discharged; The reference battery power to be discharged is the battery power that each battery cell needs to discharge from the current state to the battery system being in the cut-off discharge state; and The second calculation unit is used to obtain the energy state of the battery system based on the corresponding relationship between the reference battery power to be discharged, the current actual capacity value of each battery cell and the open circuit voltage of each battery cell and the battery power state, including: The battery power state of each battery cell when the battery system is in the cut-off discharge state is calculated based on the reference battery power to be discharged and the current actual capacity value; The energy state of the battery system is obtained based on the battery power state of each battery cell when the battery system is in a cut-off discharge state and the corresponding relationship between the open circuit voltage of each battery cell and the battery power state.

6. An electronic device comprising: at least one processor; as well as a memory communicatively connected to the at least one processor; wherein, The memory stores instructions that can be executed by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the estimation method according to any one of claims 1 to 4.

7. A non-transitory computer-readable storage medium storing computer instructions, wherein: The computer instructions are used to enable the computer to execute the estimation method according to any one of claims 1 to 4.

8. A computer program product, comprising a computer program, wherein when the computer program is executed by a processor, the computer program implements the estimation method according to any one of claims 1 to 4.

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