Battery SOC evaluation method, apparatus, and device, and medium

Abstract

A battery SOC evaluation method, apparatus, and device, and a medium. The method comprises: at different first temperatures and different first rates, acquiring charging and discharging data of a first battery cell group (101), there being at least one first battery cell group (101), and the first battery cell group (101) comprising a first battery cell (S201); on the basis of the charging and discharging data, acquiring first SOCs of the first battery cell group (101), the charging and discharging data comprising first voltages of the first battery cell group (101) (S202); establishing an association table between the first SOCs and the first temperatures, the first rates, and the first voltages (S203); acquiring a second temperature, a second rate, and a second voltage of a battery pack (102), and, by means of the association table, acquiring a second SOC of each second battery cell in the battery pack (102), the battery pack (102) comprising a plurality of second battery cells (S204). According to the method, the accuracy of battery SOC evaluation can be improved.

Description

Battery SOC evaluation method, device, equipment and medium

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on March 4, 2024, with application number 202410245133.9 and application name “Battery SOC evaluation method, device, equipment and medium”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of battery technology, and in particular to a battery SOC evaluation method, device, equipment and medium. Background Art

[0003] The battery's state of charge (SOC) is a quantitative assessment of the charge state stored in the battery. It is used to characterize the energy storage system's ability to store and release excess power, prevent overcharging and over-discharging, and ensure the safety of the energy storage system. However, the battery's SOC cannot be measured directly and can only be obtained through external characteristic parameters such as the battery's voltage.

[0004] Existing methods for estimating battery SOC combine multiple algorithms, including data-driven methods and Kalman filtering methods. However, these algorithms are used to evaluate the battery system as a whole, without evaluating each single battery in the battery system, resulting in inaccurate evaluation results.

[0005] Therefore, this application proposes an evaluation method that can improve the accuracy of SOC evaluation.

[0006] Summary of the Invention

[0007] The present application provides a battery SOC evaluation method, device, equipment and medium to solve the problems in the prior art of lack of analysis of single cells in a battery system and inaccurate battery SOC evaluation results.

[0008] In a first aspect, the present application provides a battery SOC evaluation method, comprising:

[0009] Acquire charge and discharge data of a first monomer battery at different first temperatures and different first rates, wherein the first monomer battery is at least one and includes a first monomer battery;

[0010] Acquire a first SOC of the first monomer battery according to the charge and discharge data, wherein the charge and discharge data includes a first voltage of the first monomer battery;

[0011] Establishing an association table between the first SOC, the first temperature, the first rate, and the first voltage;

[0012] The second temperature, the second rate, and the second voltage of the battery pack are acquired, and the second SOC of each second single battery in the battery pack is acquired through the association table, wherein the battery pack includes a plurality of the second single batteries.

[0013] In a possible implementation, obtaining charge and discharge data of the first battery pack at different first temperatures and different first rates includes:

[0014] According to a preset variation parameter, different first temperatures are obtained, and a measurement space is controlled to reach the first temperature, wherein the measurement space is used to place the first single battery pack;

[0015] If each of the first monomer battery packs includes only one first monomer battery pack, obtaining charge and discharge data of each of the first monomer battery packs at different first rates at each same first temperature;

[0016] If each of the first monomer battery packs includes at least one first monomer battery pack, then at each same first temperature, each of the first monomer battery packs at different first rates is obtained.

[0017] In a possible implementation, if each of the first cell groups includes only one first cell, the method further includes:

[0018] At each same first temperature, obtaining a first charge and discharge parameter of each first single battery at the same first rate;

[0019] acquiring charge and discharge data of the first single battery group according to a first average value of the first charge and discharge parameter of each of the first single batteries at the same first rate and the first charge and discharge parameter;

[0020] If each of the first cell groups includes at least one first cell, the method further includes:

[0021] At each same first temperature, obtaining a second charge-discharge parameter of each first monomer battery at the same first rate;

[0022] The charge and discharge data of the first monomer battery group is obtained according to the second average value of the first charge and discharge parameter of each of the first monomer battery groups at the same first rate and the second charge and discharge parameter.

[0023] In a possible implementation, establishing an association table of the first SOC, the first temperature, the first rate, and the first voltage includes:

[0024] For each of the first monomer battery packs, associating the first temperature and the first rate used to obtain the charge and discharge data with the first voltage in the charge and discharge data to obtain a first association set;

[0025] Associating the first voltage in the charge and discharge data used to obtain the first SOC with the first SOC to obtain a second association set;

[0026] The association table is obtained according to the first association set and the second association set; wherein the model of the first single battery is consistent with the model of the second single battery.

[0027] In a possible implementation, obtaining the second temperature, the second rate, and the second voltage of the battery pack includes:

[0028] Acquire a historical current and a historical temperature of the battery pack in a preset historical time period, and acquire the second voltage and the second rate according to the historical current;

[0029] The second temperature of the battery pack is acquired according to the historical temperature.

[0030] In a possible implementation, obtaining the second voltage according to the historical current includes:

[0031] Obtaining a current change according to the preset historical time period and the historical current;

[0032] Obtaining a first coefficient according to the current change and a first characteristic parameter of the battery pack;

[0033] Obtaining a second coefficient according to the preset historical time period and the first characteristic parameter and the second characteristic parameter of the battery pack;

[0034] The second voltage is obtained according to the first coefficient and the second coefficient.

[0035] In a possible implementation, before controlling the measurement space to reach the first temperature, the method further includes:

[0036] Obtaining a starting time node at which the humidity of the measurement space does not exceed a preset humidity;

[0037] Obtaining, according to the starting time node and the current time node, a static time length of the measurement space, wherein the static time length is a time length during which the humidity of the measurement space does not exceed the preset humidity;

[0038] If the length of the rest time exceeds a preset time length, it is confirmed that the first single battery pack is placed in the measurement space.

[0039] In a second aspect, the present application provides a battery SOC evaluation device, comprising:

[0040] an acquisition module, configured to acquire charge and discharge data of a first monomer battery at different first temperatures and different first rates, wherein the first monomer battery is at least one and includes a first monomer battery;

[0041] a processing module, configured to obtain a first SOC of the first monomer battery according to the charge and discharge data, wherein the charge and discharge data includes a first voltage of the first monomer battery;

[0042] an association module, configured to establish an association table between the first SOC, the first temperature, the first rate, and the first voltage;

[0043] The evaluation module is configured to obtain a second temperature, a second rate, and a second voltage of the battery pack, and obtain a second SOC of each second single cell in the battery pack through the association table, wherein the battery pack includes a plurality of second single cells.

[0044] In a third aspect, the present application provides a battery SOC evaluation device, comprising: at least one processor and a memory;

[0045] The memory stores computer-executable instructions;

[0046] The at least one processor executes the computer-executable instructions stored in the memory, so that the at least one processor performs the battery SOC evaluation method as described above.

[0047] In a fourth aspect, the present application provides a computer-readable storage medium having a computer program stored thereon, which implements the steps of the battery SOC evaluation method as described above when executed by a processor.

[0048] The present application provides a battery SOC assessment method, device, equipment and medium, which obtain charge and discharge data of a first single-cell group battery at different first temperatures and different first rates, wherein the first single-cell group battery is at least one and includes a first single-cell battery; obtain a first SOC of the first single-cell group battery based on the charge and discharge data, wherein the charge and discharge data includes a first voltage of the first single-cell group battery; establish an association table between the first SOC and the first temperature, the first rate and the first voltage; obtain a second temperature, a second rate and a second voltage of the battery pack, and obtain a second SOC of each second single-cell battery in the battery pack through the association table, wherein the battery pack includes multiple second single-cell batteries.

[0049] In the above method, an association table is constructed using the first single-cell battery pack, and the second SOC of each second single-cell battery in the battery pack is evaluated using the measurable data of the battery pack in the association table, thereby ensuring that the second SOC of the battery pack can be accurately estimated. When establishing the association table, the first single-cell battery pack is used as an experimental object, and charge and discharge data of the first single-cell battery pack is obtained at different first temperatures and different first rates. The first SOC of the first single-cell battery pack is obtained based on the charge and discharge data, and the measurable data such as the first temperature, the first rate, and the first voltage are associated with the first SOC to establish an association table. The second temperature, the second rate, and the second voltage of the battery pack are obtained, and the association relationship in the association table is searched, so that the second SOC of each second single-cell battery in the battery pack can be accurately and conveniently obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0051] FIG1 is a schematic diagram of a battery SOC evaluation scenario provided by an embodiment of the present application;

[0052] FIG2 is a flow chart of a battery SOC evaluation method according to an embodiment of the present application;

[0053] FIG3 is a second flow chart of a battery SOC evaluation method provided in an embodiment of the present application;

[0054] FIG4 is a third flow chart of a battery SOC evaluation method provided in an embodiment of the present application;

[0055] FIG5 is a fourth flow chart of a battery SOC evaluation method provided in an embodiment of the present application;

[0056] FIG6 is a diagram of a battery SOC evaluation device provided by an embodiment of the present invention;

[0057] FIG7 is a hardware diagram of a battery SOC evaluation device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0058] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0059] Driven by the "dual carbon" goals, the energy storage industry, as a supporting industry and key driver of energy structure adjustment, has broad application prospects in many fields such as traditional power generation, transmission and distribution, power demand side, auxiliary services and new energy. Lithium-ion batteries (referred to as lithium batteries) are electrochemical energy storage devices and are widely used in electrochemical energy storage and other fields. Electrochemical energy storage power stations are mainly composed of lithium battery packs, power conversion systems (PCS), isolation transformers, battery management systems and energy management systems to achieve overall charging and discharging control of the system; among them, the core of the electrochemical energy storage power station is the battery, and the safety of the battery directly affects the safety of the energy storage system.

[0060] The battery's state of charge (SOC) is a quantitative measure of the charge stored within a battery. It characterizes the energy storage system's ability to store and release excess charge, preventing overcharging and over-discharging and ensuring system safety. However, the battery management system (BMS) cannot directly measure SOC and can only estimate it through a comprehensive analysis of external battery parameters, such as terminal voltage. Accurate SOC assessment not only improves battery pack safety but also enhances its overall performance and service life.

[0061] However, the battery SOC estimation methods currently used in BMS systems are not only inaccurate and overly complex, but most of them evaluate the overall SOC of the system without accurately evaluating the SOC of each battery cell (single battery). This significantly reduces the scope and accuracy of the evaluation.

[0062] Therefore, this application proposes an evaluation method based on the measurement of single cells to improve the accuracy of SOC evaluation.

[0063] The following describes the implementation process of a battery SOC evaluation method proposed in this application in conjunction with the accompanying drawings and specific embodiments.

[0064] Figure 1 is a schematic diagram of a battery SOC assessment scenario provided by an embodiment of the present application. As shown in Figure 1, the system includes: a first single cell 101 and a battery pack 102; wherein the battery pack 102 includes multiple second single cells; the first single cell 101 and the second single cell are both single cells;

[0065] The battery pack 102 is composed of a plurality of second single cells, and the individual single cells in the battery pack 102 can be connected in series. The first single cell 101 can be a sampling cell, and its related data is used to establish a correlation table, which is used to express the relationship between the external characteristic parameters of the battery and the battery SOC. The correlation table can be used to estimate the SOC of each second single cell in the actual battery pack 102, and can simply and accurately identify the SOC of each single cell of the battery.

[0066] Obtaining the external characteristic parameters of the first single cell 101 includes obtaining charge and discharge data of the first single cell group 101 at different first temperatures and different first rates; wherein the first single cell group is based on the first single cell, and the first single cells can be measured separately or in combination; for example, when measuring three single cells to establish an association table, single cell a, single cell b, and single cell c in the first single cell 101 are each measured separately, or single cell d, single cell e, and single cell f in the first single cell 101 can be measured separately and some single cells are selected and measured together, and the selected single cells e and single cell f can be connected in series and measured together;

[0067] Based on the charge and discharge data of the first single-cell battery 101, a first SOC of the first single-cell battery 101 can be obtained, and an association table of the first SOC, the first temperature, the first rate, and the first voltage can be established. This association table can be used for the battery pack 102; the battery pack 102 is measured in real time to obtain a second temperature, a second rate, and a second voltage of the battery pack 102. By searching the association table, the second SOC of the battery pack 102 and each second single-cell battery in the battery pack 102 can be compared.

[0068] FIG2 is a flow chart of a battery SOC evaluation method according to an embodiment of the present application. As shown in FIG2 , the method includes:

[0069] S201 : Acquire charge and discharge data of a first monomer battery at different first temperatures and different first rates, wherein the number of the first monomer battery is at least one, and the first monomer battery includes a first monomer battery.

[0070] A first single-cell battery is placed in a measurement space, and the measurement space is controlled to reach different first temperatures, and the first single-cell battery is controlled to reach different first rates. At the different first temperatures and different first rates, charge and discharge data of the first single-cell battery is obtained; wherein the charge and discharge data is data related to battery charging and battery discharging, including charging current and discharging current, etc.; there can be multiple first single-cell batteries placed in the measurement space, each first single-cell battery is composed of first single cells, and each first single-cell battery can have only one first single cell battery, or can have one or more first single cells. The specific combination of each first single cell battery can be selected according to actual needs.

[0071] S202 : Acquire a first SOC of the first monomer battery according to the charge and discharge data, wherein the charge and discharge data includes a first voltage of the first monomer battery.

[0072] The charge and discharge data of the first single-cell battery include a first voltage and a first current of the first single-cell battery. The first voltage can be used as collectable corresponding data in the association table, and the first current can be used to calculate a first SOC of the first single-cell battery. Optionally, the first SOC is calculated using an ampere-hour integration method. The first current is the charge and discharge current of the first single-cell battery. Based on the first current and charge and discharge time of the first single-cell battery, as well as the rated capacity of the first single-cell battery, the first SOC of the first single-cell battery can be calculated using an ampere-hour integration method formula.

[0073] S203: Create an association table between the first SOC, the first temperature, the first rate, and the first voltage.

[0074] For each first single-cell battery, the charge and discharge data of the first single-cell battery at the same first temperature can be used to obtain a first SOC, and the charge and discharge data includes the first voltage at the same first temperature, and the first rate is data obtained based on the first current and rated capacity of the first single-cell battery; then, at the same first temperature, there is a first SOC, a first voltage, and a first rate; the first SOC forms a corresponding relationship with the first temperature, the first rate, and the first voltage, and an association table can be established, and each first single-cell battery can correspond to one association table.

[0075] S204 , obtaining a second temperature, a second rate, and a second voltage of the battery pack, and obtaining a second SOC of each second single battery in the battery pack through the association table, wherein the battery pack includes a plurality of second single batteries.

[0076] The association table contains a correspondence between a first SOC and a first temperature, a first rate, and a first voltage. If each second single cell of the battery pack is of the same type as the first single cell, the battery pack can use the association table. Temperature, rate, and voltage are all measurable data, while SOC is unmeasurable data. The temperature, rate, and voltage of the battery pack are measured to obtain a second temperature, a second rate, and a second voltage. The second temperature, second rate, and second voltage are mapped to the association table to find the corresponding SOC of the battery pack, and the second SOC of each second single cell can also be found.

[0077] In an embodiment of the present application, an association table is constructed using the first single-cell battery pack, and the second SOC of each second single-cell battery in the battery pack is evaluated using the measurable data of the battery pack in the association table, thereby ensuring that the second SOC of the battery pack can be accurately estimated; when establishing the association table, the first single-cell battery pack is used as an experimental object, and the charge and discharge data of the first single-cell battery pack is obtained at different first temperatures and different first rates; the first SOC of the first single-cell battery pack is obtained based on the charge and discharge data, and the measurable data such as the first temperature, the first rate, and the first voltage are associated with the first SOC to establish an association table; the second temperature, the second rate, and the second voltage of the battery pack are obtained, and the association relationship in the association table is searched, so that the second SOC of each second single-cell battery in the battery pack can be accurately and conveniently obtained.

[0078] FIG3 is a second flow chart of a battery SOC evaluation method provided in an embodiment of the present application. As shown in FIG3 , the method includes:

[0079] S301 : Acquire different first temperatures according to preset variation parameters, and control a measurement space to reach the first temperature, wherein the measurement space is used to place the first single battery pack.

[0080] The measurement space is used to place a first single battery pack. If charge and discharge data of the first single battery pack needs to be measured at different first temperatures, the measurement space needs to be controlled according to preset conditions to complete temperature control. The measurement space can be controlled to reach different first temperatures according to preset change parameters. The change of the first temperature can change according to a certain gradient.

[0081] Set the preset change parameter to a certain gradient value, and adjust the first temperature of the measurement space based on the appropriate temperature according to the gradient value. For example, 25 degrees Celsius is the appropriate temperature, and the gradient value of the first temperature is set to 10 degrees Celsius. Then the temperature setting of the first temperature can be 15 degrees Celsius, 25 degrees Celsius, 35 degrees Celsius, or 45 degrees Celsius.

[0082] In order to ensure that the environment of the measurement space for measuring the first single battery pack meets the standards, the measurement space can be preprocessed:

[0083] For example, before controlling the measurement space to reach the first temperature, the method further includes:

[0084] Obtaining a starting time node at which the humidity of the measurement space does not exceed a preset humidity;

[0085] Obtaining, according to the starting time node and the current time node, a static time length of the measurement space, wherein the static time length is a time length during which the humidity of the measurement space does not exceed the preset humidity;

[0086] If the length of the rest time exceeds a preset time length, it is confirmed that the first single battery pack is placed in the measurement space.

[0087] The humidity of the measurement space will affect the measurement of the first single-cell battery, so the measurement space should be left standing in a stable, dry environment for a period of time; when the humidity of the measurement space does not exceed the preset humidity, it is considered dry, and the preset humidity can be set to 60% RH. When the humidity of the measurement space does not exceed 60% RH, it is considered that the environment of the measurement space is dry, and the measurement space must be left standing in the dry environment for longer than the preset time. If the time exceeds, it is confirmed that the first single-cell battery is placed in the measurement space; the standing time can be set to 24 hours or longer.

[0088] The measurement space corresponds to a starting time node for achieving dryness and a current time node for maintaining dryness; based on the starting time node for drying the measurement space and the current time node for maintaining the dryness, the length of the static time of the measurement space can be confirmed.

[0089] S302 : If each of the first single cell groups includes only one first single cell, then at each same first temperature, obtain charge and discharge data of each of the first single cell groups at different first rates.

[0090] There may be multiple first single-cell battery groups, and each first single-cell battery group may have one first single cell, that is, only the charge and discharge data of the single cells are collected to establish an association table; accordingly, at the same first temperature, the charge and discharge data of the first single-cell battery group at different first rates are obtained, that is, the charge and discharge data of each individual first single cell at different first rates are obtained at the same first temperature.

[0091] S303 : If each of the first monomer battery packs includes at least one first monomer battery pack, obtain each of the first monomer battery packs at different first rates at each same first temperature.

[0092] Each first single-cell battery pack may also include multiple first single-cell batteries. Multiple first single-cell batteries are selected according to needs and the first single-cell batteries are combined. The combined first single-cell battery pack may include one first single-cell battery or multiple first single-cell batteries. That is, the charge and discharge data of the single-cell battery and the charge and discharge data of the partially combined batteries are collected to establish an association table; accordingly, at the same first temperature, the charge and discharge data of the first single-cell battery pack at different first rates are obtained, that is, the charge and discharge data of the individual and combined first single-cell batteries at different first rates are obtained at the same first temperature.

[0093] Get the charge and discharge data of the first single battery pack:

[0094] For example, if each of the first single cell battery packs includes only one first single cell, the method further includes:

[0095] At each same first temperature, obtaining a first charge and discharge parameter of each first single battery at the same first rate;

[0096] acquiring charge and discharge data of the first single battery group according to a first average value of the first charge and discharge parameter of each of the first single batteries at the same first rate and the first charge and discharge parameter;

[0097] If each of the first cell groups includes at least one first cell, the method further includes:

[0098] At each same first temperature, obtaining a second charge-discharge parameter of each first monomer battery at the same first rate;

[0099] The charge and discharge data of the first monomer battery group is obtained according to the second average value of the first charge and discharge parameter of each of the first monomer battery groups at the same first rate and the second charge and discharge parameter.

[0100] Regardless of whether each first cell group includes only one first cell group or each first cell group includes at least one first cell group, the charge and discharge parameters of each corresponding first cell group can be collected, and the charge and discharge parameters are data such as the measured charge and discharge current. If each first cell group includes only one first cell group, a first charge and discharge parameter is obtained, and if each first cell group includes at least one first cell group, a second charge and discharge parameter is obtained. The first charge and discharge parameter and the second charge and discharge parameter can be directly selected as the charge and discharge data of the first cell group, or can be selected as the charge and discharge data of the first cell group after taking the average.

[0101] In the embodiment of the present application, charge and discharge data of a single cell is measured to establish an association table related to the single cell for estimating the SOC, thereby facilitating the evaluation of the SOC of the battery pack.

[0102] FIG4 is a flow chart of a battery SOC evaluation method according to an embodiment of the present application. As shown in FIG4 , the method includes:

[0103] S401 : For each first monomer battery pack, associate the first temperature and the first rate used to obtain the charge and discharge data with the first voltage in the charge and discharge data to obtain a first association set.

[0104] The association table of the first SOC with the first temperature, the first rate, and the first voltage is not a function expression; the association table is only used to associate corresponding input values ​​and output values, where the input values ​​include temperature, rate, and voltage, and the output value includes SOC; when the input value is measured, the association table can be queried to obtain the corresponding output value, that is, the SOC of the battery is evaluated; for each first single-cell battery, a first temperature and a first voltage in the charge and discharge data measured at a first rate are correlated with each other, forming a first association set.

[0105] S402 : Associating the first voltage in the charge and discharge data used to obtain the first SOC with the first SOC to obtain a second association set.

[0106] For each first single-cell battery, the charge and discharge data measured at a first temperature and a first rate also include a first current. The first current can be used to calculate a first SOC. The calculated first SOC is associated with the first voltage in the charge and discharge data measured at the first temperature and the first rate to form a second association set.

[0107] S403: Obtain the association table according to the first association set and the second association set; wherein the model of the first single battery is consistent with the model of the second single battery.

[0108] For each of the first monomer battery groups, associating the first voltage with the first SOC in the charge and discharge data at the same first temperature and the same first rate to obtain the association table;

[0109] Combining the first association set and the second association set to obtain an association table between the first temperature, the first rate, the first voltage, and the first SOC, that is, obtaining an association table between the temperature, the rate, the voltage, and the SOC; when the model of the first single cell is the same as the model of the second single cell, the association table can be used for measuring the battery pack corresponding to the second single cell;

[0110] The battery pack can be connected in series. In order to evaluate the second SOC of the second single cells therein, the same negative electrode can be set for each second single cell, and based on the charge and discharge data of the negative electrode and the positive electrode of each second single cell, the second temperature, second rate, and second voltage of each second single cell are obtained, and the second SOC of each second single cell is obtained by reference to the association table.

[0111] In the embodiment of the present application, the SOC state of each second single cell during the charge and discharge process can be accurately evaluated, and the SOC difference between different second single cells in the battery pack can be identified. The results can be applied to the charging and balancing strategies for abnormal batteries to improve the consistency of the system.

[0112] FIG5 is a fourth flow chart of a battery SOC evaluation method provided in an embodiment of the present application. As shown in FIG5 , the method includes:

[0113] S501 : Acquire a historical current and a historical temperature of the battery pack in a preset historical time period, and acquire the second voltage and the second rate according to the historical current.

[0114] The battery pack has a corresponding temperature value in the actual usage environment. The historical temperature can be collected within a preset historical time period. The historical temperature can be obtained by collecting one or more temperatures within the preset historical time period and taking the average value. The historical current of the battery pack must also be obtained within the preset historical time period. The historical current can be collected continuously. The second voltage and the second rate can be calculated based on the historical current and historical temperature and the corresponding formula. The second rate can be obtained based on the second current and rated capacity of the second single battery.

[0115] The second voltage can be obtained according to the following calculation:

[0116] For example, according to the preset historical time period and the historical current, the current change amount is obtained;

[0117] Obtaining a first coefficient according to the current change and a first characteristic parameter of the battery pack;

[0118] Obtaining a second coefficient according to the preset historical time period and the first characteristic parameter and the second characteristic parameter of the battery pack;

[0119] The second voltage is obtained according to the first coefficient and the second coefficient.

[0120] Obtaining a first value of the first coefficient according to the current change and a first parameter of the first characteristic parameter of the battery pack; obtaining a second value of the first coefficient according to the current change and a second parameter of the first characteristic parameter of the battery pack;

[0121] Obtaining a third value of the second coefficient based on a preset historical time period, a first parameter of the first characteristic parameter, and a third parameter of the second characteristic parameter; obtaining a fourth value of the second coefficient based on a preset historical time period, a second parameter of the first characteristic parameter, and a fourth parameter of the second characteristic parameter;

[0122] Obtain a second voltage according to the first and second values ​​of the first coefficient and the third and fourth values ​​of the second coefficient:

[0123] Among them, V is the voltage compensation value, and the voltage compensation value plus the voltage value in the current state can obtain the second voltage; dI is the current change; dt is the preset historical time period; exp(·) is a function with a natural number as the base; Rd, Cd, Rd2, and Cd2 are different battery cell characteristic parameters, namely, the first parameter of the first characteristic parameter, the third parameter of the second characteristic parameter, the second parameter of the first characteristic parameter, and the fourth parameter of the second characteristic parameter; * is the multiplication sign.

[0124] S502: Acquire the second temperature of the battery pack according to the historical temperature.

[0125] The historical temperature may be obtained by collecting one or more historical temperatures within a preset historical time period and averaging the values, and may be directly used as the second temperature.

[0126] This application can also take the impedance characteristics of the battery cell into account, so that the evaluation results can more accurately reflect the actual available power of the battery pack; at the same time, based on the evaluated SOC results and combined with relevant control strategies, the safety performance and service life of the lithium battery can be further improved.

[0127] FIG6 is a diagram of a battery SOC evaluation device provided by an embodiment of the present invention. As shown in FIG6 , the device includes: an acquisition module 601 , a processing module 602 , an association module 603 , and an evaluation module 604 ;

[0128] The acquisition module 601 is configured to acquire charge and discharge data of a first monomer battery at different first temperatures and different first rates, wherein the first monomer battery is at least one and includes a first monomer battery.

[0129] The acquisition module 601 is further configured to acquire different first temperatures according to a preset variation parameter, and control a measurement space to reach the first temperature, wherein the measurement space is used to place the first single battery pack;

[0130] If each of the first monomer battery packs includes only one first monomer battery pack, then at each same first temperature, obtaining charge and discharge data of each of the first monomer battery packs at different first rates;

[0131] If each of the first monomer battery packs includes at least one first monomer battery pack, then at each same first temperature, each of the first monomer battery packs at different first rates is obtained.

[0132] The processing module 602 is configured to obtain a first SOC of the first monomer battery according to the charge and discharge data, wherein the charge and discharge data includes a first voltage of the first monomer battery.

[0133] The association module 603 is configured to establish an association table between the first SOC, the first temperature, the first ratio, and the first voltage.

[0134] The association module 603 is further configured to associate, for each of the first monomer battery groups, the first temperature and the first rate used to obtain the charge and discharge data with the first voltage in the charge and discharge data to obtain a first association set;

[0135] Associating the first voltage in the charge and discharge data used to obtain the first SOC with the first SOC to obtain a second association set;

[0136] The association table is obtained according to the first association set and the second association set; wherein the model of the first single battery is consistent with the model of the second single battery.

[0137] The evaluation module 604 is configured to obtain a second temperature, a second rate, and a second voltage of the battery pack, and obtain a second SOC of each second single cell in the battery pack through the association table, wherein the battery pack includes a plurality of second single cells.

[0138] The evaluation module 604 is further configured to obtain a historical current and a historical temperature of the battery pack in a preset historical time period, and obtain the second voltage and the second rate according to the historical current;

[0139] The second temperature of the battery pack is acquired according to the historical temperature.

[0140] The present application also provides a battery SOC evaluation device, comprising: at least one processor and a memory;

[0141] The memory stores computer-executable instructions;

[0142] The at least one processor executes the computer-executable instructions stored in the memory, so that the at least one processor performs a battery SOC evaluation method.

[0143] Figure 7 is a hardware diagram of a battery SOC assessment device provided in an embodiment of the present invention. As shown in Figure 7 , the battery SOC assessment device 70 provided in this embodiment includes at least one processor 701 and a memory 702. The device 70 also includes a communication component 703. The processor 701, memory 702, and communication component 703 are connected via a bus 704.

[0144] In a specific implementation process, at least one processor 701 executes the computer-executable instructions stored in the memory 702 , so that the at least one processor 701 performs the above-mentioned battery SOC evaluation method.

[0145] The specific implementation process of the processor 701 can be found in the above method embodiment. Its implementation principle and technical effects are similar and will not be repeated here in this embodiment.

[0146] In the embodiment shown in FIG. 7 , it should be understood that the processor may be a central processing unit (CPU), other general-purpose processors, digital signal processors (DSP), or application-specific integrated circuits (ASICs). A general-purpose processor may be a microprocessor or any conventional processor. The steps of the method disclosed in the present invention may be directly executed by a hardware processor or by a combination of hardware and software modules within the processor.

[0147] The memory may include a high-speed memory (Random Access Memory, RAM), and may also include a non-volatile memory (NVM), such as at least one disk memory.

[0148] The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus. Buses can be classified into address buses, data buses, and control buses. For ease of illustration, the buses in the drawings of this application are not limited to just one bus or just one type of bus.

[0149] The present application also provides a computer-readable storage medium, in which computer-executable instructions are stored. When a processor executes the computer-executable instructions, the battery SOC evaluation method as described above is implemented.

[0150] The computer-readable storage medium mentioned above can be implemented by any type of volatile or non-volatile memory device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic memory, flash memory, magnetic disk, or optical disk. The computer-readable storage medium can be any available medium that can be accessed by a general-purpose or special-purpose computer.

[0151] An exemplary readable storage medium is coupled to a processor so that the processor can read information from the readable storage medium and write information to the readable storage medium. Of course, the readable storage medium can also be an integral part of the processor. The processor and the readable storage medium can be located in an application specific integrated circuit (ASIC). Of course, the processor and the readable storage medium can also exist in a device as discrete components.

[0152] The division of units described above is merely a logical functional division. In actual implementation, other divisions may be employed. For example, multiple units or components may be combined or integrated into another system, or some features may be omitted or not implemented. Furthermore, any coupling or direct coupling or communication connection shown or discussed between units may be an indirect coupling or communication connection via an interface, device, or unit, and may be electrical, mechanical, or other.

[0153] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0154] Those skilled in the art will appreciate that all or part of the steps in the above-described method embodiments can be implemented using hardware associated with program instructions. The aforementioned program can be stored in a computer-readable storage medium. When executed, the program performs the steps of the above-described method embodiments. The aforementioned storage medium includes various media capable of storing program code, such as ROM, RAM, magnetic disks, or optical disks.

[0155] Finally, it should be noted that those skilled in the art will readily identify other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. The present invention is intended to cover any variations, uses, or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art not disclosed herein. The present invention is not limited to the precise structure described above and illustrated in the accompanying drawings, and various modifications and variations may be made without departing from the scope thereof. The scope of the present invention is limited solely by the appended claims.

Claims

1. A battery SOC evaluation method, characterized in that: include: Acquire charge and discharge data of a first monomer battery at different first temperatures and different first rates, wherein the first monomer battery is at least one and includes a first monomer battery; Acquire a first SOC of the first monomer battery according to the charge and discharge data, wherein the charge and discharge data includes a first voltage of the first monomer battery; Establishing an association table between the first SOC, the first temperature, the first rate, and the first voltage; The second temperature, the second rate, and the second voltage of the battery pack are acquired, and the second SOC of each second single battery in the battery pack is acquired through the association table, wherein the battery pack includes a plurality of the second single batteries.

2. The method according to claim 1, characterized in that The step of obtaining charge and discharge data of the first battery pack at different first temperatures and different first rates includes: According to a preset variation parameter, different first temperatures are obtained, and a measurement space is controlled to reach the first temperature, wherein the measurement space is used to place the first single battery pack; If each of the first monomer battery packs includes only one first monomer battery pack, obtaining charge and discharge data of each of the first monomer battery packs at different first rates at each same first temperature; If each of the first monomer battery packs includes at least one first monomer battery pack, then at each same first temperature, each of the first monomer battery packs at different first rates is obtained.

3. The method according to claim 2, characterized in that If each of the first cell groups includes only one first cell, the method further includes: At each same first temperature, obtaining a first charge and discharge parameter of each first single battery at the same first rate; acquiring charge and discharge data of the first single battery group according to a first average value of the first charge and discharge parameter of each of the first single batteries at the same first rate and the first charge and discharge parameter; If each of the first cell groups includes at least one first cell, the method further includes: At each same first temperature, obtaining a second charge-discharge parameter of each first monomer battery at the same first rate; The charge and discharge data of the first monomer battery group is obtained according to the second average value of the first charge and discharge parameter of each of the first monomer battery groups at the same first rate and the second charge and discharge parameter.

4. The method according to claim 1, wherein The establishing of an association table between the first SOC, the first temperature, the first rate, and the first voltage includes: For each of the first monomer battery packs, associating the first temperature and the first rate used to obtain the charge and discharge data with the first voltage in the charge and discharge data to obtain a first association set; Associating the first voltage in the charge and discharge data used to obtain the first SOC with the first SOC to obtain a second association set; The association table is obtained according to the first association set and the second association set; wherein the model of the first single battery is consistent with the model of the second single battery.

5. The method according to claim 1, wherein The obtaining of the second temperature, the second rate, and the second voltage of the battery pack includes: Acquire a historical current and a historical temperature of the battery pack in a preset historical time period, and acquire the second voltage and the second rate according to the historical current; The second temperature of the battery pack is acquired according to the historical temperature.

6. The method according to claim 5, characterized in that The obtaining the second voltage according to the historical current includes: Obtaining a current change according to the preset historical time period and the historical current; Obtaining a first coefficient according to the current change and a first characteristic parameter of the battery pack; Obtaining a second coefficient according to the preset historical time period and the first characteristic parameter and the second characteristic parameter of the battery pack; The second voltage is obtained according to the first coefficient and the second coefficient.

7. The method according to claim 2, characterized in that Before controlling the measurement space to reach the first temperature, the method further includes: Obtaining a starting time node at which the humidity of the measurement space does not exceed a preset humidity; Obtaining, according to the starting time node and the current time node, a static time length of the measurement space, wherein the static time length is a time length during which the humidity of the measurement space does not exceed the preset humidity; If the length of the rest time exceeds a preset time length, it is confirmed that the first single battery pack is placed in the measurement space.

8. A battery SOC evaluation device, characterized in that: include: an acquisition module, configured to acquire charge and discharge data of a first monomer battery at different first temperatures and different first rates, wherein the first monomer battery is at least one and includes a first monomer battery; a processing module, configured to obtain a first SOC of the first monomer battery according to the charge and discharge data, wherein the charge and discharge data includes a first voltage of the first monomer battery; an association module, configured to establish an association table between the first SOC, the first temperature, the first rate, and the first voltage; The evaluation module is configured to obtain a second temperature, a second rate, and a second voltage of the battery pack, and obtain a second SOC of each second single cell in the battery pack through the association table, wherein the battery pack includes a plurality of second single cells.

9. A battery SOC evaluation device, characterized in that: include: at least one processor and memory; The memory stores computer-executable instructions; The at least one processor executes the computer-executable instructions stored in the memory, so that the at least one processor performs the battery SOC evaluation method according to any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the battery SOC evaluation method according to any one of claims 1 to 7 are implemented.

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