Methods, apparatus, electronic equipment, media, and procedures for determining the state of charge of batteries.

Abstract

This application provides a method, apparatus, electronic device, medium, and program product for determining the state of charge of a battery, relating to the field of batteries. The method for determining the state of charge of a battery includes: obtaining the state of charge (SOC) and state of equilibrium (SOH) of the battery, and a first correspondence between them and the battery's expansion force value; determining the required displacement (DOD) of the battery; and minimizing the difference between the maximum and minimum expansion force values ​​of the battery based on the first correspondence and the required DOD of the battery to obtain an upper limit of the battery's charging SOC, used to control battery charging.

Description

Technical Field

[0001] This application relates to the field of batteries, and more particularly to a method, apparatus, electronic device, medium, and program product for determining the state of charge of a battery. Background Technology

[0002] The expansion force inside the battery can cause "breathing fatigue" in the battery connectors, which may eventually lead to fatigue fracture of the connectors, thus affecting the battery's lifespan.

[0003] The above statements are for the purpose of providing background information in relation to this application only and do not necessarily constitute prior art. Summary of the Invention

[0004] One technical problem this disclosure aims to solve is to provide a method, apparatus, electronic device, medium, and program product for determining the state of charge of a battery, which can reduce the alternating stress caused by battery expansion force, extend the service life of connectors, and thus improve the service life of the battery.

[0005] In a first aspect, this application provides a method for determining the state of charge of a battery, comprising: obtaining the state of charge (SOC) and state of health (SOH) of the battery, and a first correspondence between them and the swelling force value of the battery; determining the required depth of discharge (DOD) of the battery; and based on the first correspondence and the required DOD of the battery, minimizing the difference between the maximum swelling force value and the minimum swelling force value of the battery to obtain an upper limit of the charging SOC of the battery, for controlling the charging of the battery.

[0006] In the technical solution of this application embodiment, the required DOD of the battery is determined, and the optimal upper limit of charging SOC is determined. The battery is charged according to the maximum SOC limit. Charging minimizes the stress amplitude of the battery's expansion force, thereby reducing the alternating stress caused by the battery's expansion force, extending the service life of the connectors, and consequently extending the battery's service life.

[0007] In some embodiments, minimizing the difference between the maximum and minimum expansion force values ​​of the battery based on the first correspondence and the required DOD of the battery to obtain the upper limit of the battery's charging SOC includes: taking the upper limit of the battery's charging SOC as a variable, according to the first correspondence, minimizing the difference as the objective, and based on the first constraint, the optimal solution of the upper limit of the charging SOC is obtained, wherein the first constraint includes the SOC being greater than or equal to the difference between the maximum allowable charging SOC and the required DOD of the battery, and less than or equal to the maximum allowable charging SOC; the second constraint includes the upper limit of the charging SOC being greater than or equal to the sum of the minimum allowable discharging SOC and the required DOD of the battery, and less than or equal to the maximum allowable charging SOC; the third constraint includes the minimum allowable discharging SOC being less than or equal to the lower limit of the discharging SOC, where the lower limit of the discharging SOC is the difference between the upper limit of the charging SOC and the required DOD of the battery.

[0008] In this embodiment, an optimization algorithm is used to determine the optimal charging SOC upper limit. Furthermore, the required DOD of the battery is also known. Thus, the DOD range of the battery can be optimized, and the charging strategy of the battery can be determined based on the DOD range. Since the difference between the maximum expansion force value and the minimum expansion force value of the battery is the smallest, the alternating stress caused by the battery expansion force can be reduced, thereby extending the service life of the connector and thus extending the service life of the battery.

[0009] In some embodiments, based on a first correspondence and the required DOD of the battery, the difference between the maximum and minimum expansion force values ​​of the battery is minimized to obtain the upper limit of the battery's charging SOC: According to the first correspondence and the required DOD of the battery, the difference between the maximum and minimum expansion force values ​​corresponding to the current upper limit of the charging SOC is calculated; the upper limit of the charging SOC is adjusted with a predetermined step size, and the difference is reduced through iterative calculation; if the difference is less than a first threshold or the number of iterations is greater than a second threshold, the current upper limit of the charging SOC is taken as the optimal solution. By describing the steps of the optimization algorithm and designing a reasonable upper limit of iteration, the optimal upper limit of the charging SOC can be calculated efficiently, thereby providing a basis for battery usage strategies, reducing the occurrence of breakage events caused by battery connector fatigue, and finding a balance between computational efficiency and result quality, avoiding problems such as invalid calculations or non-convergence.

[0010] In some embodiments, determining the required DOD of the battery includes: determining the total energy consumption of the battery based on the vehicle's expected driving range and the battery's average energy consumption per unit mile; and determining the required DOD of the battery based on the battery's total energy consumption and the battery's total energy. By rationally determining the required DOD of the battery using the vehicle's expected driving range, the battery's average energy consumption per unit mile, and the battery's total energy, an optimal balance can be found between battery safety, lifespan, and performance, reducing safety risks or lifespan reduction caused by inappropriate DOD.

[0011] In some embodiments, the average energy consumption per unit mile of the battery is determined by: acquiring daily mileage data of the vehicle within a predetermined time period; calculating daily battery discharge energy data of the vehicle; and determining the average energy consumption per unit mile of the battery within the predetermined time period based on the daily mileage data and the daily discharge energy data. Compared to the DOD (Data on Discharge) read directly from the BMS (Battery Management System), this disclosure takes into account the changes in battery operating conditions during operation, which is more in line with the actual usage of the vehicle and facilitates better control of the DOD range within a range beneficial to battery life, thereby improving battery life.

[0012] In some embodiments, the estimated mileage is either the mileage input by the user or a mileage predicted based on the user's historical data. This embodiment makes the solution of this disclosure applicable to both scenarios where the user knows the mileage for the day and scenarios where the mileage is unknown, thus expanding the scope of application.

[0013] In some embodiments, if the State of Harm (SOH) of the battery meets the SOH when the battery cell is in the top-casing state, the step of obtaining the upper limit of the charging SOC is performed. The battery cell being in the top-casing state indicates that abnormal pressure has been generated inside the cell. In this case, the step of optimizing the upper limit of the charging SOC is performed in a timely manner to reduce the alternating stress caused by battery expansion force. This reduces the increased computational load on the BMS due to daily calculations of the upper limit of the charging SOC, and allows for timely optimization of the upper limit of the charging SOC, thereby extending battery life.

[0014] In some embodiments, the State of Charge (SOH) of the battery cell in the top case state is determined by: determining a second correspondence between the battery's SOH and the number of charge-discharge cycles; determining the number of charge-discharge cycles when the battery cell is in the top case state; and, based on the second correspondence, determining the battery's SOH corresponding to the number of charge-discharge cycles when the battery cell is in the top case state. Calculating the SOH of the battery cell in the top case state facilitates determining when the battery needs to perform the step of determining the optimal solution for the upper limit of the charging SOC. Subsequently, by designing a reasonable cycle upper limit, the optimal charging SOC upper limit can be obtained, allowing users to determine the optimal charging strategy for the battery, thereby improving battery lifespan.

[0015] In some embodiments, determining the number of charge-discharge cycles when the battery cell is in the top-case state includes: determining a third correspondence between the battery's maximum expansion force value and the number of charge-discharge cycles; determining the growth rate of the maximum expansion force value with the number of charge-discharge cycles based on the third correspondence; and determining the number of charge-discharge cycles when the battery cell is in the top-case state based on the growth rate. By determining the number of charge-discharge cycles when the battery cell is in the top-case state, it is easier to determine the State of Harmony (SOH) of the battery corresponding to the number of charge-discharge cycles when the battery cell is in the top-case state based on the second correspondence, thereby determining whether the battery cell is in the top-case state and thus determining when to plan the battery usage strategy.

[0016] In some embodiments, determining the number of charge-discharge cycles when the battery cell is in the top-case state based on the growth rate includes: determining that the battery cell is in the top-case state when the growth rates corresponding to the first occurrence of adjacent charge-discharge cycle numbers are the same; and taking the previous charge-discharge cycle number among the first occurrences of adjacent charge-discharge cycle numbers as the number of charge-discharge cycle cycles when the battery cell is in the top-case state. Subsequently, by comparing the State of Charge (SOH), it can be determined whether an optimization algorithm should be used to calculate the optimal charging SOC upper limit, thereby determining the upper and lower limits of the SOC for a specific DOD and realizing the determination of the battery charging strategy.

[0017] Secondly, this disclosure provides a battery state of charge determination device, comprising: a relationship determination module configured to acquire a first correspondence between the battery's state of charge (SOC) and state of health (SOH), and the battery's expansion force value; a depth of discharge (DOD) determination module configured to determine the required depth of discharge (DOD) of the battery; and a charging SOC upper limit determination module configured to minimize the difference between the battery's maximum expansion force value and minimum expansion force value based on the first correspondence and the battery's required DOD, thereby obtaining the battery's charging SOC upper limit for controlling battery charging.

[0018] In this embodiment, the required DOD of the battery was determined, and the optimal upper limit of the charging SOC was determined. The battery is charged according to the maximum SOC limit. Charging minimizes the stress amplitude of the battery's expansion force, thereby reducing the alternating stress caused by the battery's expansion force, extending the service life of the connectors, and consequently extending the battery's service life.

[0019] Thirdly, this disclosure provides an electronic device, including: a processor; and a memory coupled to the processor for storing instructions, which, when executed by the processor, cause the processor to perform the battery state of charge determination method as described above.

[0020] Fourthly, this disclosure provides a computer-readable storage medium having computer instructions stored thereon, which, when executed by a processor, implement the above-described method for determining the state of charge of a battery.

[0021] Fifthly, this disclosure also proposes a computer program product, including: computer instructions that, when executed by a processor, implement the above-described method for determining the state of charge of a battery.

[0022] Other features and advantages of this disclosure will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the drawings without creative effort.

[0024] Figure 1 This is a flowchart illustrating a method for determining the state of charge of a battery according to one or more embodiments;

[0025] Figure 2 This is a graph showing the relationship between SOC and expansion force value under a certain SOH according to one or more embodiments;

[0026] Figure 3 This is a schematic diagram of a process for obtaining the upper limit of the charging state of a battery according to one or more embodiments;

[0027] Figure 4 This is a graph showing the relationship between the maximum expansion force of a battery according to one or more embodiments and the number of charge-discharge cycles.

[0028] Figure 5 A graph showing the relationship between the growth rate and SOH according to one or more embodiments;

[0029] Figure 6 This is a block diagram of a battery state of charge determination apparatus according to one or more embodiments;

[0030] Figure 7 This is a block diagram of an electronic device according to one or more embodiments. Detailed Implementation

[0031] The embodiments of this application will be described in further detail below with reference to the accompanying drawings and examples. The detailed description of the following embodiments and the accompanying drawings are used to illustrate the principles of this application by way of example, but should not be used to limit the scope of this application, that is, this application is not limited to the described embodiments.

[0032] In the description of this application, it should be noted that, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," and "outer," etc., indicating orientation or positional relationships, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. Furthermore, the terms "first," "second," and "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. "Vertical" is not vertical in the strict sense, but within the allowable tolerance range. "Parallel" is not parallel in the strict sense, but within the allowable tolerance range.

[0033] At the same time, it should be understood that, for ease of description, the dimensions of the various parts shown in the accompanying drawings are not drawn according to actual scale.

[0034] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this disclosure or its application or use.

[0035] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0036] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0037] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0038] To make the objectives, technical solutions, and advantages of this disclosure clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0039] During the operation of an electric vehicle, the charging and discharging process of the battery causes chemical reactions inside the battery, resulting in the periodic expansion and contraction of the battery volume. This volume change generates expansion forces within the battery pack, especially between batteries and between batteries and connectors. Since the connectors inside the battery pack are usually fixed, these expansion forces are converted into alternating stresses on the connectors. Over time, these periodic alternating stresses can cause "breathing fatigue" in the connectors, potentially leading to fatigue fracture and affecting the stability and safety of the battery system.

[0040] The DOD (Depth of Discharge) range of a battery corresponds to its expansion force. The DOD range is a key variable for controlling battery expansion force; therefore, determining a suitable DOD range can extend battery life. This disclosure provides a method for determining the state of charge (SOC) of a battery. By determining the required DOD and finding the upper limit of the SOC, the DOD range of the battery is optimized to reduce the alternating stress caused by battery expansion force, extend the service life of connectors, and thus improve the battery's lifespan. The solution of this disclosure will be described below with reference to specific embodiments.

[0041] like Figure 1 As shown, Figure 1 This is a flowchart illustrating a method for determining the state of charge of a battery according to one or more embodiments, which includes steps S11-S13.

[0042] In step S11, the first correspondence between the battery's SOC (State of Charge) and SOH (State of Health) and the battery's expansion force value is obtained.

[0043] The expansion force value of a battery is related to its SOC and SOH. The expansion force value of a battery with any SOC and any SOH can be obtained in advance through testing.

[0044] The first correspondence can be represented by a curve of the battery's SOC and SOH and the battery's expansion force value, or by a function, or by a table. This disclosure does not limit the form in which the first correspondence is represented.

[0045] The first correspondence is, for example, represented by the formula. ,in, This indicates the expansion force value of the battery.

[0046] In some embodiments, expansion force test data under different aging conditions can be obtained through testing. For example, the cycle aging range of the battery cell can be set to the DOD range required by the specifications, which is typically 0% to 100%. During the battery aging process, the battery cell needs to be clamped by a fixture, and the preload force is the same as the preload force of the battery in the battery pack.

[0047] like Figure 2 As shown, Figure 2 This diagram illustrates the relationship between State of Charge (SOC) and Expansion Force at a specific State of Health (SOH) according to one or more embodiments. Based on this diagram, the expansion force value of the battery corresponding to any SOC at a given SOH can be determined. Those skilled in the art should understand that this diagram is for illustrative purposes only, and other diagrams showing the relationship between SOC and Expansion Force at any SOH can also be drawn.

[0048] In step S12, the required DOD for the battery is determined.

[0049] The DOD required by the battery can be obtained directly from the BMS (Battery Management System), or it can be calculated from some vehicle data.

[0050] Steps S11 and S12 can be performed in any order.

[0051] In step S13, based on the first correspondence and the required DOD of the battery, the difference between the maximum expansion force value and the minimum expansion force value of the battery is minimized to obtain the upper limit of the battery's charging SOC, which is used to control battery charging.

[0052] For example, the maximum expansion force value of the battery The minimum expansion force of the battery The difference between the battery's maximum and minimum expansion force values By optimizing the charging SOC limit , making Minimum, so that it can be based on the upper limit of charging SOC. Charge the vehicle's battery.

[0053] In this embodiment, the required DOD of the battery was determined, and the optimal upper limit of the charging SOC was determined. The battery is charged according to the maximum SOC limit. Charging minimizes the stress amplitude of the battery's expansion force, thereby reducing the alternating stress caused by the battery's expansion force, extending the service life of the connectors, and consequently extending the battery's service life.

[0054] The above embodiments can be executed by the BMS, for example, after the BMS calculates the upper limit of the battery's charging SOC, it charges the battery based on the upper limit of the charging SOC. Alternatively, it can be executed by other controllers, such as a cloud computing machine, which calculates the upper limit of the battery's charging SOC and sends it to the BMS so that the BMS can charge the battery based on the upper limit of the charging SOC, thereby reducing the computing power requirements of the BMS.

[0055] In some embodiments, minimizing the difference between the maximum and minimum expansion force values ​​of the battery based on the first correspondence and the required DOD of the battery to obtain the upper limit of the battery's charging SOC includes: taking the upper limit of the battery's charging SOC as a variable, according to the first correspondence, minimizing the difference as the objective, and based on the first constraint, the optimal solution of the upper limit of the charging SOC is obtained, wherein the first constraint includes the SOC being greater than or equal to the difference between the maximum allowable charging SOC and the required DOD of the battery, and less than or equal to the maximum allowable charging SOC; the second constraint includes the upper limit of the charging SOC being greater than or equal to the sum of the minimum allowable discharging SOC and the required DOD of the battery, and less than or equal to the maximum allowable charging SOC; the third constraint includes the minimum allowable discharging SOC being less than or equal to the lower limit of the discharging SOC, where the lower limit of the discharging SOC is the difference between the upper limit of the charging SOC and the required DOD of the battery.

[0056] In some embodiments, the required DOD for the battery is determined, assuming a maximum charging SOC. The lower limit of SOC for this discharge The maximum expansion force of the battery The minimum expansion force of the battery The difference between the battery's maximum and minimum expansion force values ,in, The maximum allowable charge state of charge (SOC) is typically 100% or 95%. This indicates the SOH (Solar OH) of a battery under a certain aging condition.

[0057] To prevent battery over-discharge or over-charge, the upper and lower limits of the State of Charge (SOC) need to be set: , ,in, The minimum permissible discharge state of charge (SOC) is recommended to be above 10% to prevent additional mileage requirements.

[0058] By optimizing the charging SOC limit , making Minimum, so that it can be based on the upper limit of charging SOC. Charge the vehicle's battery. For example, set the maximum SOC (State of Charge) for that charge. This parameter is displayed to the user, who can then charge the battery accordingly.

[0059] The lower limit of the DOD range required for the battery is The upper limit of the DOD range required for the battery is .

[0060] In this embodiment, an optimization algorithm is used to determine the optimal charging SOC upper limit. Furthermore, the required DOD of the battery is also known. Thus, the DOD range of the battery can be optimized, and the charging strategy of the battery can be determined based on the DOD range. Since the difference between the maximum expansion force value and the minimum expansion force value of the battery is the smallest, the alternating stress caused by the battery expansion force can be reduced, thereby extending the service life of the connector and thus extending the service life of the battery.

[0061] In some embodiments, the upper limit of the battery's state of charge (SOC) is obtained as follows: Figure 3 As shown, Figure 3 This is a schematic diagram of a process for obtaining the upper limit of the charging state of a battery according to one or more embodiments, which includes steps S31-S34.

[0062] In step S31, based on the first correspondence and the DOD required by the battery, the difference between the maximum expansion force value and the minimum expansion force value corresponding to the current charging SOC upper limit is calculated.

[0063] For example, based on the first correspondence, and based on the first constraint, the second constraint, and the third constraint, the difference between the maximum expansion force value and the minimum expansion force value corresponding to the current charging SOC upper limit is calculated.

[0064] This step allows for setting the upper limit of the charging SOC. Initially, the difference between the maximum and minimum expansion force values ​​is used as the objective function to calculate the current... Objective function value .

[0065] In some embodiments, execution stopping conditions for obtaining the optimal solution to the upper limit of charging SOC can be preset. For example, execution stopping conditions include the difference being less than a first threshold or the number of iterations being greater than a second threshold. By setting execution stopping conditions such as function convergence thresholds or maximum number of iterations, the stopping time of the optimization algorithm can be controlled, a balance can be found between computational efficiency and result quality, and problems such as invalid computation or failure to converge can be avoided.

[0066] In step S32, the upper limit of the charging SOC is adjusted by a predetermined step size, and the difference is reduced through iterative calculation.

[0067] Determine an appropriate step size so that the objective function value is at the new point. The value decreases at +d, where d is the search direction.

[0068] In step S33, if the difference is less than the first threshold or the number of iterations is greater than the second threshold, the current charging SOC upper limit is taken as the optimal solution.

[0069] For example, update the current point Set the new point as the starting point and continue executing step S32 until the optimization algorithm meets the stopping condition, then return to the current point. If the first threshold is the optimal solution, then proceed to step S32; otherwise, continue. The first and second thresholds can be set according to the actual situation.

[0070] The ultimate goal of this optimization algorithm is to minimize the difference between the maximum and minimum expansion force values, thereby obtaining the optimal upper limit of charging SOC. The optimization algorithm can be, for example, least squares algorithm, linear minimum algorithm, neural network algorithm, backpropagation neural network algorithm, genetic algorithm, etc. This scheme does not limit the specific algorithm.

[0071] In the above embodiments, by describing the steps of the optimization algorithm and designing a reasonable cycle limit, the optimal charging SOC limit can be calculated efficiently, thereby providing a basis for battery usage strategies and reducing the occurrence of battery connector breakage events caused by breathing fatigue.

[0072] In some embodiments, determining the required DOD of the battery includes: determining the total energy consumption of the battery based on the vehicle's expected driving range and the battery's average energy consumption per unit mile; and determining the required DOD of the battery based on the total energy consumption of the battery and the battery's total energy.

[0073] The estimated mileage can be either the mileage input by the user or a mileage predicted based on the user's historical data. For example, if the user knows their current mileage, the estimated mileage is the mileage input by the user. Alternatively, the vehicle's mileage can be predicted based on the user's past driving data. This embodiment makes the solution of this disclosure applicable to both scenarios where the user knows their current mileage and scenarios where the mileage is unknown, thus expanding its application scope.

[0074] If the average energy consumption per unit distance of the battery is The mileage is expressed as... Then the total energy consumption of the battery .

[0075] The total energy of a battery is equal to the product of its energy when it was not aged (e.g., when it left the factory) and its current state of equilibrium (SOH). For example, using the formula... This indicates the total energy of the battery. This refers to the energy level of the battery before it ages. The current state of energy (SOH) of the battery. The required depot (DOD) of the battery is the ratio of the battery's total energy consumption to its total energy output, i.e. .

[0076] Obtaining the required DOD (Device Direct Discharge) for the battery directly from the vehicle may be affected by factors such as current measurement errors and initial SOC (State of Charge) errors, which accumulate over time. In this embodiment, the required DOD is rationally determined by considering the vehicle's estimated mileage, the battery's average energy consumption per mile, and the battery's total energy. This allows for an optimal balance between battery safety, lifespan, and performance, reducing safety risks or lifespan degradation caused by inappropriate DOD. Furthermore, this disclosure considers the estimated mileage when calculating the required DOD. For example, if the driver knows the distance to be traveled and the vehicle's average energy consumption per kilometer before departure, they can accurately calculate how much electricity the battery needs to release, i.e., the required DOD, thus enabling more precise planning of charging timing and amount.

[0077] In some embodiments, the average energy consumption per unit mileage of the battery is determined by: acquiring daily mileage data of the vehicle within a predetermined time period; calculating daily discharge energy data of the vehicle's battery; and determining the average energy consumption per unit mileage of the battery within a predetermined time period based on the daily mileage data and the daily discharge energy data.

[0078] For example, collecting daily mileage data from vehicles, such as obtaining the daily mileage through the vehicle's mileage signal. , This indicates the number of days. Then, daily battery discharge energy data is collected. This can be achieved by acquiring real-time current and voltage data of the battery through a BMS (Battery Management System). Current is typically measured by a shunt or Hall effect sensor within the battery, while voltage is sampled from individual cell or module voltages. (Battery discharge energy data...) This allows us to obtain the average energy consumption per unit distance of the battery over a predetermined time. For example, .

[0079] In this embodiment, by acquiring the aforementioned daily usage habits, the average energy consumption per unit mile of the battery can be calculated, which facilitates the calculation of the required depth of discharge (DOD) of the battery. Compared to the DOD read directly from the BMS, this disclosure takes into account the changes in battery operating conditions during operation. For example, the average energy consumption per unit mile of the battery is updated and adjusted according to actual usage conditions, which can better adapt to the impact of battery aging and environmental factors on energy consumption. This makes it more consistent with the actual usage of the vehicle and more accurately reflects the depth of discharge required by the battery to meet future travel needs. This makes it easier to better control the DOD range within a range that is beneficial to battery life, thereby improving battery life.

[0080] In some embodiments, if the State of Harmony (SOH) of the battery satisfies the SOH when the battery cell is in the top case state, the step of obtaining the upper limit of the charging State of Charge (SOC) is performed.

[0081] When a battery cell is in its top-casing state (specifically, the JR (JellyRoll, bare cell) top casing inside the cell), causing deformation or damage to the battery casing, it indicates abnormal pressure inside the cell. This could affect the battery's sealing and cause problems such as electrolyte leakage. In such cases, timely optimization of the charging SOC upper limit is crucial to reduce alternating stress caused by battery expansion. This reduces the increased computational load on the BMS due to daily calculations of the charging SOC upper limit and allows for timely optimization, thereby extending battery life.

[0082] In some embodiments, the State of Harm (SOH) of the battery cell when it is in the top case state is determined by: determining a second correspondence between the battery's SOH and the number of charge-discharge cycles; determining the number of charge-discharge cycles when the battery cell is in the top case state; and determining the battery's SOH corresponding to the number of charge-discharge cycles when the battery cell is in the top case state based on the second correspondence.

[0083] The second correspondence can be represented by a curve of the battery's SOH and the number of charge-discharge cycles, or by a function, or by a table. This disclosure does not limit the form in which the second correspondence is represented.

[0084] For example, the second correspondence is expressed by the formula It means that, among them, Indicates the number of charge / discharge cycles. Indicates the first The state of harm (SOH) of the battery corresponding to the number of charge-discharge cycles.

[0085] By calculating the State of Harmony (SOH) of the battery cells when they are in the top case state, it is easier to determine when the battery needs to perform the step of determining the optimal solution for the upper limit of the charging SOC. Subsequently, by designing a reasonable cycle upper limit, the optimal charging SOC upper limit can be obtained, which helps users determine the optimal charging strategy for the battery, thereby improving battery life.

[0086] In some embodiments, determining the number of charge-discharge cycles when the battery cell is in the top case state includes: determining a third correspondence between the battery's maximum expansion force value and the number of charge-discharge cycles; determining the growth rate of the maximum expansion force value with the number of charge-discharge cycles based on the third correspondence; and determining the number of charge-discharge cycles when the battery cell is in the top case state based on the growth rate.

[0087] The third correspondence can be represented by a curve between the battery's maximum expansion force and the number of charge-discharge cycles, or by a function, or by a table. This disclosure does not limit the form in which the third correspondence is represented.

[0088] For example, the third correspondence is expressed by the formula It means that, among them, Indicates the number of charge / discharge cycles. Indicates the first The maximum expansion force value of the battery corresponding to the number of charge-discharge cycles.

[0089] For example, such as Figure 4 As shown, Figure 4 This is a graph showing the relationship between the maximum expansion force of a battery according to one or more embodiments and the number of charge-discharge cycles. This graph can be plotted by obtaining expansion force test data under different aging conditions and using the test results.

[0090] Based on this relationship diagram, the growth rate of the maximum expansion force with the number of charge-discharge cycles can be determined. For example, the growth rate... This allows us to determine the number of charge-discharge cycles when the battery cell is in the top case state.

[0091] By determining the number of charge-discharge cycles when the battery cell is in the top case state, it is easier to determine the SOH of the battery corresponding to the number of charge-discharge cycles when the battery cell is in the top case state based on the second correspondence, thereby determining whether the battery cell is in the top case state and thus determining when to plan the battery usage strategy.

[0092] In some embodiments, determining the number of charge-discharge cycles when the battery cell is in the top case state based on the growth rate includes: determining that the battery cell is in the top case state when the growth rates corresponding to adjacent charge-discharge cycle numbers are the same for the first time; and taking the previous charge-discharge cycle number among the adjacent charge-discharge cycle numbers as the number of charge-discharge cycle numbers when the battery cell is in the top case state.

[0093] After the JR top casing inside the battery cell, this growth rate remains constant. For example, during the first charge / discharge cycle of the battery... Circle and the first circle When the cells are in the same position (i.e., the battery cells are in the top case state), record the state when the cells are in the top case. for .like Figure 5 As shown, Figure 5 This is a graph showing the relationship between the growth rate and SOH according to one or more embodiments. By comparing the SOH, it can be determined whether an optimization algorithm should be used to calculate the optimal charging SOC upper limit, thereby determining the upper and lower limits of the SOC for a specific DOD and thus determining the battery charging strategy.

[0094] The solution disclosed herein is applicable to situations where the user's daily mileage is known and a suitable DOD range for the battery is recommended, as well as situations where a suitable DOD range for the battery is recommended based on past vehicle operation data.

[0095] For example, the user inputs their estimated daily driving mileage. Based on the average energy consumption per unit mile, the vehicle's total energy consumption is calculated, and then the battery's required DOD (Demand of Energy) is calculated based on this total energy consumption. Using the battery's maximum State of Charge (SOC) as a variable, and aiming to minimize the difference between the battery's maximum and minimum expansion force, while considering multiple constraints, the optimal solution for the maximum SOC can be obtained through iterative calculation. Before the user begins driving, it is recommended to charge the battery to this maximum SOC to minimize the stress amplitude of expansion force during the day's driving, reducing the risk of breakage due to fatigue of battery connectors.

[0096] For example, the system acquires and displays the user's daily mileage data over a recent period. The user can then input their estimated mileage for the day based on this historical data. The total energy consumption of the vehicle is calculated based on the average energy consumed per unit mile, and the required DOD (Device Operating Distance) for the battery is then calculated based on this total energy consumption. Using the battery's maximum State of Charge (SOC) as a variable, and aiming to minimize the difference between the battery's maximum and minimum expansion force values, the optimal solution for the maximum SOC is obtained through iterative calculation, taking into account multiple constraints. Before the user begins driving, it is recommended that they charge the battery to this maximum SOC to minimize the stress amplitude of expansion force during the day's driving, reducing the risk of breakage due to fatigue of battery connectors.

[0097] Those skilled in the art will understand that, in the methods described above in specific embodiments, the order in which the steps are written does not imply a strict execution order and does not constitute any limitation on the real-time process. The specific execution order of each step should be determined by its function and possible internal logic.

[0098] The above are schematic diagrams of some embodiments of the battery state of charge determination method. Below, the battery state of charge determination device will be further described with reference to the accompanying drawings.

[0099] Figure 6 This is a block diagram of a battery state of charge determination device according to one or more embodiments. The battery state of charge determination device 6 includes a relationship determination module 61, a DOD determination module 62, and a charging SOC upper limit determination module 63.

[0100] The relationship determination module 61 is configured to obtain a first correspondence between the battery's SOC and SOH and the battery's expansion force value.

[0101] DOD determination module 62 is configured to determine the DOD required for the battery.

[0102] The charging SOC upper limit determination module 63 is configured to obtain the charging SOC upper limit of the battery by minimizing the difference between the maximum expansion force value and the minimum expansion force value of the battery based on the first correspondence and the DOD required by the battery, and to control the charging of the battery.

[0103] In this embodiment, the required DOD of the battery is determined, and the optimal upper limit of the charging SOC is also determined. The battery is charged according to the upper limit of the charging SOC. Charging minimizes the stress amplitude of the battery's expansion force, thereby reducing the alternating stress caused by the battery's expansion force, extending the service life of the connectors, and consequently extending the battery's service life.

[0104] In some embodiments, the charging SOC upper limit determination module 63 is configured to use the battery's charging SOC upper limit as a variable, and based on a first correspondence, with the goal of minimizing the difference, obtain the optimal solution for the charging SOC upper limit based on a first constraint, a second constraint, and a third constraint. The first constraint includes that the SOC is greater than or equal to the difference between the maximum allowable charging SOC and the battery's required DOD, and less than or equal to the maximum allowable charging SOC. The second constraint includes that the charging SOC upper limit is greater than or equal to the sum of the minimum allowable discharging SOC and the battery's required DOD, and less than or equal to the maximum allowable charging SOC. The third constraint includes that the minimum allowable discharging SOC is less than or equal to the lower limit of the discharging SOC, where the lower limit of the discharging SOC is the difference between the charging SOC upper limit and the battery's required DOD.

[0105] In this embodiment, the optimal charging SOC upper limit is determined by an optimization algorithm, and the required DOD of the battery is also known. In this way, the DOD range of the battery can be optimized, and the charging strategy of the battery can be determined based on the DOD range. Since the difference between the maximum expansion force value and the minimum expansion force value of the battery is the smallest, the alternating stress caused by the battery expansion force can be reduced, thereby extending the service life of the connector and thus extending the service life of the battery.

[0106] In some embodiments, the charging SOC upper limit determination module 63 is configured to calculate the difference between the maximum expansion force value and the minimum expansion force value corresponding to the current charging SOC upper limit based on the first correspondence and the DOD required by the battery; adjust the charging SOC upper limit with a predetermined step size, and reduce the difference through iterative calculation; and take the current charging SOC upper limit as the optimal solution if the difference is less than a first threshold or the number of iterations is greater than a second threshold.

[0107] In the above embodiments, by describing the steps of the optimization algorithm and designing a reasonable cycle limit, the optimal charging SOC limit can be calculated efficiently, thereby providing a basis for battery usage strategies and reducing the occurrence of battery connector breakage events caused by breathing fatigue. Furthermore, this embodiment can find a balance between computational efficiency and result quality, avoiding problems such as invalid calculations or non-convergence.

[0108] In some embodiments, the DOD determination module 62 is configured to determine the total energy consumption of the battery based on the vehicle's expected mileage and the battery's average energy consumption per unit mile; and to determine the required DOD of the battery based on the total energy consumption and the battery's total energy.

[0109] In this embodiment, the required DOD of the battery is reasonably determined by the vehicle's expected mileage, the battery's average energy consumption per unit mile, and the battery's total energy. This enables the battery to find the optimal balance between safety, lifespan, and performance, reducing safety risks or lifespan loss caused by improper DOD.

[0110] In some embodiments, the DOD determination module 62 is configured to acquire daily mileage data of the vehicle within a predetermined time period; calculate daily battery discharge energy data of the vehicle; and determine the average energy consumption per unit mileage of the battery within the predetermined time period based on the daily mileage data and the daily discharge energy data.

[0111] By acquiring the above-mentioned daily usage habits, the average energy consumption per unit mile of the battery can be calculated, which makes it easier to calculate the required DOD of the battery. Compared with the DOD read directly from the BMS, this disclosure takes into account the changes in the battery's operating conditions during operation, which is more in line with the actual use of the vehicle and makes it easier to control the DOD range within a range that is beneficial to battery life, thereby improving battery life.

[0112] In some embodiments, the estimated mileage is either the mileage input by the user or a mileage predicted based on the user's historical data. This embodiment makes the solution of this disclosure applicable to both scenarios where the user knows the mileage for the day and scenarios where the mileage is unknown, thus expanding the scope of application.

[0113] In some embodiments, the charging SOC upper limit determination module 63 is configured to perform the step of determining the optimal solution for the charging SOC upper limit when the SOH of the battery satisfies the SOH when the battery cell is in the top case state.

[0114] When a battery cell is in the top-casing state, it indicates that abnormal pressure has been generated inside the cell. In this case, it's crucial to promptly optimize the charging SOC upper limit to reduce alternating stress caused by battery expansion. This reduces the increased computational load on the BMS due to daily calculations of the charging SOC upper limit and allows for timely optimization, thereby extending battery life.

[0115] In some embodiments, the State of Harm (SOH) of the battery cell when it is in the top case state is determined by: determining a second correspondence between the battery's SOH and the number of charge-discharge cycles; determining the number of charge-discharge cycles when the battery cell is in the top case state; and determining the battery's SOH corresponding to the number of charge-discharge cycles when the battery cell is in the top case state based on the second correspondence.

[0116] By calculating the State of Harmony (SOH) of the battery cells when they are in the top case state, it is easier to determine when the battery needs to perform the step of determining the optimal solution for the upper limit of the charging SOC. Subsequently, by designing a reasonable cycle upper limit, the optimal charging SOC upper limit can be obtained, which helps users determine the optimal charging strategy for the battery, thereby improving battery life.

[0117] In some embodiments, determining the number of charge-discharge cycles when the battery cell is in the top case state includes: determining a third correspondence between the battery's maximum expansion force value and the number of charge-discharge cycles; determining the growth rate of the maximum expansion force value with the number of charge-discharge cycles based on the third correspondence; and determining the number of charge-discharge cycles when the battery cell is in the top case state based on the growth rate.

[0118] By determining the number of charge-discharge cycles when the battery cell is in the top case state, it is easier to determine the SOH of the battery corresponding to the number of charge-discharge cycles when the battery cell is in the top case state based on the second correspondence, thereby determining whether the battery cell is in the top case state and thus determining when to plan the battery usage strategy.

[0119] In some embodiments, determining the number of charge-discharge cycles when the battery cell is in the top case state based on the growth rate includes: determining that the battery cell is in the top case state when the growth rates corresponding to adjacent charge-discharge cycle numbers are the same for the first time; and taking the previous charge-discharge cycle number among the adjacent charge-discharge cycle numbers as the number of charge-discharge cycle numbers when the battery cell is in the top case state.

[0120] By determining the number of charge-discharge cycles when the battery cell is in the top case state, it is possible to determine whether to use an optimization algorithm to calculate the optimal charging SOC upper limit by comparing the SOH. This will determine the upper and lower limits of the SOC for the specific DOD and thus determine the battery charging strategy.

[0121] A battery state-of-charge determination device can exist in the form of an electronic device. For example... Figure 7 As shown, Figure 7 This is a block diagram of an electronic device according to one or more embodiments. The electronic device 7 includes a memory 71 and a processor 72. The memory 71 may be a disk, flash memory, or any other non-volatile storage medium. The memory is used to store instructions in the above embodiments. The processor 72 is coupled to the memory 71 and may be implemented as one or more integrated circuits, such as a microprocessor or microcontroller. The processor 72 is used to execute the instructions stored in the memory.

[0122] In some embodiments, the processor 72 is coupled to the memory 71 via a BUS bus 7. The electronic device 7 can also be connected to an external storage device 75 via a storage interface 74 to access external data, and can also be connected to a network or another computer system (not shown) via a network interface 76. Further details are omitted here.

[0123] In this embodiment, the electronic device stores data instructions in a memory and processes the instructions in a processor, which can reduce the alternating stress caused by battery expansion force, extend the service life of the connector, and thus improve the service life of the battery.

[0124] In other embodiments, this application provides a computer-readable storage medium having computer program instructions stored thereon, which, when executed by a processor, implement the steps of the methods described above. Those skilled in the art will understand that embodiments of this application can be provided as methods, apparatus, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable non-transitory storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0125] In some embodiments of the application, a computer program product is also provided, including computer program instructions that, when executed by a processor, implement the method of any of the above embodiments.

[0126] The description of the various embodiments above tends to emphasize the differences between the various embodiments. The similarities or similarities between them can be referred to, and for the sake of brevity, they will not be repeated here.

[0127] This concludes the detailed description of the present application. To avoid obscuring the concept of the application, some details known in the art have not been described. Those skilled in the art can fully understand how to implement the technical solutions disclosed herein based on the above description.

[0128] The methods and systems of this application may be implemented in many ways. For example, they may be implemented by software, hardware, firmware, or any combination of software, hardware, and firmware. The above-described order of steps for the methods is for illustrative purposes only, and the steps of the methods of this application are not limited to the order specifically described above, unless otherwise specifically stated. Furthermore, in some embodiments, this application may also be implemented as a program recorded on a recording medium, the program including machine-readable instructions for implementing the methods according to this application. Thus, this application also covers recording media storing programs for performing the methods according to this application.

[0129] While specific embodiments of this application have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of this application. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of this application. The scope of this application is defined by the appended claims.

Claims

1. A method for determining the state of charge of a battery, characterized in that, include: Obtain the first correspondence between the battery's state of charge (SOC) and state of health (SOH), and the battery's expansion force value; Determine the required depth of discharge (DOD) for the battery; Based on the first correspondence and the required DOD of the battery, the difference between the maximum and minimum expansion force values ​​of the battery is minimized to obtain the upper limit of the battery's charging SOC, which is used to control the charging of the battery. The upper limit of the battery's charging SOC is used as a variable. Based on the first correspondence and with minimizing the difference as the objective, the optimal solution for the upper limit of the charging SOC is obtained based on the first, second, and third constraints. The first constraint includes that the battery's SOC during the calculation of the maximum and minimum expansion force values ​​is greater than or equal to the difference between the maximum permissible charging SOC and the required DOD of the battery, and less than or equal to the maximum permissible charging SOC. The second constraint includes that the upper limit of the charging SOC is greater than or equal to the sum of the minimum permissible discharging SOC and the required DOD of the battery, and less than or equal to the maximum permissible charging SOC. The third constraint includes that the minimum permissible discharging SOC is less than or equal to the lower limit of the discharging SOC, where the lower limit of the discharging SOC is the difference between the upper limit of the charging SOC and the required DOD of the battery.

2. The method for determining the state of charge of a battery according to claim 1, characterized in that, Based on the first correspondence and the required DOD of the battery, minimizing the difference between the maximum and minimum expansion force values ​​of the battery to obtain the upper limit of the battery's charging SOC further includes: Based on the first correspondence and the required DOD of the battery, calculate the difference between the maximum expansion force value and the minimum expansion force value corresponding to the current charging SOC upper limit; The upper limit of the charging SOC is adjusted by a predetermined step size, and the difference is reduced through iterative calculation. If the difference is less than the first threshold or the number of iterations is greater than the second threshold, the current charging SOC upper limit is taken as the optimal solution.

3. The method for determining the state of charge of a battery according to claim 1 or 2, characterized in that, Determining the required DOD for the battery includes: The total energy consumption of the battery is determined based on the vehicle's expected driving mileage and the battery's average energy consumption per unit mileage. The required DOD for the battery is determined based on the battery's total energy consumption and total energy.

4. The method for determining the state of charge of a battery according to claim 3, characterized in that, The average energy consumption per unit distance of the battery is determined by the following: Obtain the daily mileage data of the vehicle within the predetermined time period; Calculate the daily discharge energy data of the vehicle's battery; Based on the daily mileage data and the daily discharge energy data, the average energy consumption per unit mileage of the battery within the predetermined time period is determined.

5. The method for determining the state of charge of a battery according to claim 3, characterized in that, The estimated mileage is either the mileage input by the user or the mileage predicted based on the user's historical data.

6. The method for determining the state of charge of a battery according to claim 1 or 2, characterized in that, If the SOH of the battery satisfies the SOH when the battery cell is in the top case state, the step of obtaining the upper limit of the charging SOC is performed.

7. The method for determining the state of charge of a battery according to claim 6, characterized in that, The state of harmonics (SOH) of the battery cell when it is in the top case state is determined by the following: Determine a second correspondence between the state of harmonics (SOH) of the battery and the number of charge-discharge cycles; Determine the number of charge-discharge cycles when the battery cell is in the top case state; Based on the second correspondence, the SOH of the battery is determined corresponding to the number of charge-discharge cycles when the battery cell is in the top case state.

8. The method for determining the state of charge of a battery according to claim 7, characterized in that, Determining the number of charge-discharge cycles when the battery cell is in the top case state includes: Determine the third correspondence between the maximum expansion force value of the battery and the number of charge-discharge cycles; Based on the third correspondence, the growth rate of the maximum expansion force value with the number of charge-discharge cycles is determined; Based on the growth rate, the number of charge-discharge cycles of the battery cell when it is in the top case state is determined.

9. The method for determining the state of charge of a battery according to claim 8, characterized in that, Based on the growth rate, the number of charge-discharge cycles when the battery cell is in the top case state is determined as follows: If the growth rates corresponding to adjacent charge-discharge cycles are the same for the first time, it is determined that the battery cell is in the top case state; The number of the previous charge-discharge cycle in the first occurrence of adjacent charge-discharge cycle counts is taken as the number of charge-discharge cycle counts when the battery cell is in the top case state.

10. A battery state of charge determination device, characterized in that, include: The relationship determination module is configured to obtain a first correspondence between the battery's state of charge (SOC) and state of health (SOH) and the battery's expansion force value. A DOD determination module is configured to determine the required depth of discharge (DOD) of the battery. A charging SOC upper limit determination module is configured to minimize the difference between the maximum and minimum expansion force values ​​of the battery based on the first correspondence and the required DOD of the battery, thereby obtaining the charging SOC upper limit of the battery. This module is used to control the charging of the battery. The module uses the charging SOC upper limit as a variable, and based on the first correspondence and minimizing the difference as the objective, obtains the optimal solution for the charging SOC upper limit based on a first constraint, a second constraint, and a third constraint. The first constraint includes that the battery's SOC during the calculation of the maximum and minimum expansion force values ​​is greater than or equal to the difference between the maximum allowable charging SOC and the required DOD of the battery, and less than or equal to the maximum allowable charging SOC. The second constraint includes that the charging SOC upper limit is greater than or equal to the sum of the minimum allowable discharging SOC and the required DOD of the battery, and less than or equal to the maximum allowable charging SOC. The third constraint includes that the minimum allowable discharging SOC is less than or equal to the lower limit of the discharging SOC, where the lower limit of the discharging SOC is the difference between the charging SOC upper limit and the required DOD of the battery.

11. An electronic device, characterized in that, include: processor; as well as A memory coupled to the processor is used to store instructions that, when executed by the processor, cause the processor to perform the battery state-of-charge determination method as described in any one of claims 1 to 9.

12. A computer-readable storage medium storing computer instructions thereon, characterized in that, When executed by a processor, the computer instructions implement the battery state-of-charge determination method according to any one of claims 1 to 9.

13. A computer program product, characterized in that, include: The method includes computer instructions that, when executed by a processor, implement the battery state-of-charge determination method according to any one of claims 1 to 9.

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