Battery control method, battery control program, and method for using a secondary battery system
The battery control method enhances the reuse of secondary batteries by accurately estimating their state and extending their lifespan through state estimation, adaptation, and suppression control, addressing the instability of batteries with unknown histories.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- TOYOTA BATTERY CO LTD
- Filing Date
- 2024-11-19
- Publication Date
- 2026-05-29
AI Technical Summary
Existing methods for controlling secondary batteries with unknown manufacturing processes or histories cannot fully utilize their performance due to the lack of accurate state grasping, leading to unstable operations like overcharging and over-discharging.
A battery control method that includes state estimation, automatic adaptation, and suppression control processes to estimate the battery's charge level and state, update parameters, and limit output based on a state estimation model, ensuring the battery operates within optimal performance levels.
Enables the reuse of secondary batteries by accurately estimating their state and extending their lifespan while maximizing performance, even with unknown origins.
Smart Images
Figure 2026088886000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to, for example, a battery control method, a battery control program, and a usage method of a secondary battery system using a secondary battery with an unknown manufacturing process or usage history.
Background Art
[0002] In recent years, recycling of secondary batteries that have completed use in a given application for use in other applications has become common. However, when using a secondary battery, if battery parameters for grasping the state of the secondary battery cannot be grasped, problems such as unstable battery control due to overcharging, over-discharging, etc. of the secondary battery occur. Therefore, techniques for grasping the deterioration state of secondary batteries are disclosed in Patent Documents 1-4.
[0003] The method for detecting internal information of a secondary battery described in Patent Document 1 is a method for detecting internal information of a secondary battery, which includes a first step of obtaining a charge / discharge curve specific to a positive electrode material and a charge / discharge curve specific to a negative electrode material as basic data, and obtaining a charge / discharge curve of the battery to be detected as a measured value; a second step of obtaining a charge / discharge curve of the positive electrode and a charge / discharge curve of the negative electrode inside the battery to be detected by using the charge / discharge curve specific to the positive electrode material, the charge / discharge curve specific to the negative electrode material, the charge / discharge curve of the battery to be detected as the measured value, and a predetermined correction parameter; and a third step of outputting at least one of the charge / discharge curve of the positive electrode, the charge / discharge curve of the negative electrode, and the correction parameter used in the calculation obtained in the second step.
Prior Art Documents
Patent Documents
[0004]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0005] However, the technology described in Patent Document 1 cannot be used until performance data, including performance variations when new and performance including used batteries, has been obtained through testing. This presents a problem in that it can only be used in a way that suppresses the actual battery performance, taking into account performance variations.
[0006] This invention has been made in view of the above circumstances, and aims to promote the reuse of secondary batteries of unknown origin while fully utilizing their performance. [Means for solving the problem]
[0007] One embodiment of the battery control method according to the present invention includes: a state estimation process that acquires the charge / discharge current, battery voltage, and temperature of a secondary battery to estimate the charge level and state of the secondary battery; an automatic adaptation process that updates the battery parameters applied to the state estimation model used in the state estimation process to match the current state of the secondary battery; and a suppression control process that implements suppression control to extend the life of the secondary battery by limiting the output of the secondary battery based on the estimation results using the state estimation model, and is performed by an automatic calculation process by a computer, wherein the suppression control process is suppressed until the battery parameters show a degree of fit equal to or greater than a preset threshold.
[0008] One embodiment of the battery control program according to the present invention includes: a state estimation process that acquires the charge / discharge current, battery voltage, and temperature of a secondary battery to estimate the charge level and state of the secondary battery; an automatic adaptation process that updates the battery parameters applied to the state estimation model used in the state estimation process to match the current state of the secondary battery; and a suppression control process that implements suppression control to extend the life of the secondary battery by limiting the output of the secondary battery based on the estimation results using the state estimation model, and the suppression control process is suppressed until the battery parameters show a degree of fit equal to or greater than a preset threshold.
[0009] One aspect of the method for using the secondary battery system according to the present invention involves: operating at a first performance level in which charge and discharge operations are performed by applying pre-set standard parameters based on the battery type of the secondary battery and pre-set upper and lower voltage limits based on the battery type of the secondary battery; operating at a second performance level in which charge and discharge operations are performed by applying a charge rate estimation process that applies battery parameters calculated based on the degradation state of the secondary battery to a state estimation model, and applying upper and lower voltage limits according to the degradation state of the secondary battery calculated by the state estimation model, and input / output power limits according to the charge rate of the secondary battery; and performing charge and discharge operations according to the state of the secondary battery by applying a power limit value calculated by the secondary battery state estimation process and an automatic adaptation process that updates the battery parameters to match the current state of the secondary battery. A method for using a secondary battery system, wherein operation at a third performance level is performed, and one of the first, second, and third performance levels is specified to operate the secondary battery, wherein operation at the third performance level includes: a state estimation process that acquires the charge / discharge current, battery voltage, and temperature of the secondary battery to estimate the charge level and state of the secondary battery; an automatic adaptation process that updates the battery parameters applied to the state estimation model used in the state estimation process to match the current state of the secondary battery; and a suppression control process that implements suppression control to extend the life of the secondary battery by limiting the output of the secondary battery based on the estimation results using the state estimation model, and the suppression control process is suppressed until the battery parameters show a degree of fit equal to or greater than a preset threshold. [Effects of the Invention]
[0010] According to the battery control method, battery control program, and secondary battery system utilization method of the present invention, it is possible to promote the reuse of secondary batteries of unknown origin while fully utilizing their performance. [Brief explanation of the drawing]
[0011] [Figure 1] This is a flowchart illustrating how to use the secondary battery system according to Embodiment 1. [Figure 2] This is a flowchart illustrating the operation flow of the first performance level of the secondary battery system according to Embodiment 1. [Figure 3] This is a flowchart illustrating the operation flow of the second performance level of the secondary battery system according to Embodiment 1. [Figure 4] This is a flowchart illustrating the flow of the initial degradation estimation process according to Embodiment 1. [Figure 5] This is a flowchart illustrating the battery parameter estimation process according to Embodiment 1. [Figure 6] This is a flowchart illustrating the operation flow of the second performance level of the secondary battery system according to Embodiment 1. [Modes for carrying out the invention]
[0012] For clarity of explanation, the following descriptions and drawings have been omitted and simplified as appropriate. Furthermore, each element shown in the drawings as a functional block performing various processes can be composed of a CPU (Central Processing Unit), memory, and other circuits in hardware terms, and implemented in software terms by programs loaded into memory. Therefore, it will be understood by those skilled in the art that these functional blocks can be implemented in various ways using hardware alone, software alone, or a combination thereof, and are not limited to any one of these. In each drawing, the same elements are denoted by the same reference numeral, and redundant explanations have been omitted where necessary.
[0013] Furthermore, the program described above includes, when loaded into a computer, a set of instructions (or software code) for causing the computer to perform one or more of the functions described in the embodiments. The program may be stored in a non-temporary computer-readable medium or a physical storage medium. Examples, but not limited to, include random-access memory (RAM), read-only memory (ROM), flash memory, solid-state drive (SSD) or other memory technologies, CD-ROM, digital versatile disc (DVD), Blu-ray® disc or other optical disc storage, magnetic cassette, magnetic tape, magnetic disk storage or other magnetic storage devices. The program may be transmitted over a temporary computer-readable medium or a communication medium. Examples, but not limited to, include temporary computer-readable medium or a communication medium that includes electrically, optically, acoustically, or otherwise propagating signals.
[0014] Furthermore, in the method of using the secondary battery system according to Embodiment 1 described below, the charging and discharging of the secondary battery is carried out by an automated process in which one or more programs executed on a computer such as an ECU (Electric Control Unit) work in coordination.
[0015] Embodiment 1 The following description explains how to use a secondary battery system that reuses secondary batteries. In the battery usage method according to Embodiment 1, regardless of whether the secondary battery is used as a battery pack combining multiple batteries or not, the battery parameters and performance evaluation will be performed on the battery cell alone, so the term "battery cell" will be used in the description. In addition, in the secondary battery system usage method according to Embodiment 1, there are no restrictions on the type of secondary battery, but for the purposes of this explanation, lithium-ion secondary batteries will be used.
[0016] In the method of using the secondary battery system according to Embodiment 1, recycling is enabled even for a battery cell with unknown background information for which information regarding the design and manufacture of the battery cell is difficult to obtain. Further, in the method of using the secondary battery system according to Embodiment 1, since the accuracy of information for grasping the current characteristics of the battery cell is improved while being used in a specific application, the unused period of the battery cell can be shortened. A specific description of the method of using the secondary battery system according to Embodiment 1 will be given below.
[0017] FIG. 1 shows a flowchart for explaining the method of using the secondary battery system according to Embodiment 1. As shown in FIG. 1, in the secondary battery system according to Embodiment 1, the secondary battery is operated by designating any one of three performance levels. For example, when the operation at the first performance level (step S1) is designated, the operation at the first performance level in step S1 is continued. When the operation at the second performance level (step S2) is designated, after the operation at the first performance level in step S1 is performed once, the battery system shifts to the operation at the second performance level in step S2. Further, when the operation at the third performance level (step S3) is designated, after the operation at the first performance level and the operation at the second performance level in step S1 are each performed once, the battery system shifts to the operation at the third performance level in step S3. In FIG. 1, steps Sa and Sb are shown as determination processes for determining at which performance level to operate. Further, in the operation at the third performance level, in order to end the use of the secondary battery based on whether the battery has reached the end of its life, step Sc for determining whether the secondary battery has reached the end of its life is shown.
[0018] Here, each of the operations at the first performance level, the second performance level, and the third performance level will be described. In the operation at the first performance level, a preset standard parameter is applied based on the type of the secondary battery, and a charge / discharge operation is performed by applying a preset upper and lower limit voltage based on the type of the secondary battery. In this operation at the first performance level, for example, in the case of a ternary system secondary battery, the lower limit voltage is set to 3V and the upper limit voltage is set to 4.2V, and battery control is performed such that the charge rate is estimated based on the battery voltage.
[0019] During operation at the second performance level, while performing charge rate estimation processing that applies battery parameters calculated based on the degradation state of the secondary battery to the state estimation model, the upper and lower limit voltages are set according to the degradation state of the secondary battery calculated by the state estimation model, and the input / output power is limited according to the charge rate of the secondary battery, and the charge / discharge operation is performed. For example, during operation at the second performance level, battery control is performed to estimate the open circuit voltage (OCV), which is the release voltage, from the measured voltage and correct the charge rate estimated by current integration. During operation at the second performance level, by more accurately extracting the parameters used for controlling the secondary battery, it is suitable for applications that require a certain level of estimation accuracy for the upper and lower limit voltages and charge rate estimation.
[0020] During operation at the third performance level, the charge / discharge operation according to the state of the secondary battery is performed by applying the power limit value calculated by the state estimation processing of the secondary battery and the automatic adaptation processing that updates the battery parameters to match the current state of the secondary battery. For example, during operation at the third performance level, the life, lithium deposition suppression, power limit, etc. are calculated from the acquired battery parameters and more detailed control is performed. The operation at the third performance level can calculate the power limit that can maximize the life and performance of the secondary battery, so the information obtained by charge / discharge can be reflected in the battery model.
[0021] The following sections will describe in detail the operation at the first to third performance levels. First, Figure 2 shows a flowchart illustrating the operation flow at the first performance level of the secondary battery system according to Embodiment 1. As shown in Figure 2, in operation at the first performance level, product information of the battery cell is first entered (step S11), regardless of whether the characteristics of the battery cell are known or not. Specifically, in the method of using the secondary battery system according to Embodiment 1, in step S11, information including at least the battery type of the battery cell to be used is entered into the computer as product information. Here, secondary batteries differ in that they include lead-acid batteries, nickel-metal hydride batteries, lithium-ion batteries, etc., depending on the type of active material used. Therefore, in the method of using the secondary battery system according to Embodiment 1, information on which material the battery cell to be used is made of (lead-acid battery, nickel-metal hydride battery, lithium-ion battery, etc.) is provided to the computer as the battery type.
[0022] Next, in step S12, standard parameters predetermined for each type of battery cell to be used are provisionally determined as battery parameters. Here, the standard parameters in the secondary battery utilization method according to Embodiment 1 are publicly available information, for example, values predetermined by the business operator that reuses the battery cells based on information published on the website of the material manufacturer that supplies the battery cell materials. For example, the standard parameters include the thickness of the electrode foil, the thickness of the separator, the density of the active material layer coated on the electrode foil, the specific capacity of the active material layer, and the electrode capacity of the active material layer.
[0023] Next, in step S13, it is determined whether the secondary battery is usable or not. Specifically, in step S13, for example, it is checked whether the voltage range of the secondary battery is within the normal range, or whether there are any visible defects such as leakage. If the secondary battery is normal (usable), the process in the next step S14 is performed. On the other hand, if a defect is found in the secondary battery in step S13, the use of that secondary battery is terminated.
[0024] In step S13, step S14 is performed to measure the dimensions of the available secondary battery, and step S15 is performed to assemble the target secondary battery into a state where it can be charged and discharged. Subsequently, in operation at the first performance level, the upper and lower voltage limits are set in advance based on the battery parameters provisionally set in step S12 according to the battery type, and charging and discharging operations are performed while applying input / output power limits based on these upper and lower voltage limits (step S16). In the secondary battery system according to Embodiment 1, if operation at the first performance level is specified (the NO branch of step Sa), the charging and discharging operation in step S16 is continued. On the other hand, in the secondary battery system according to Embodiment 1, if operation at the second performance level is specified (the YES branch of step Sa), the control of the secondary battery is shifted to the second performance level (step S2).
[0025] Figure 3 shows a flowchart illustrating the operation flow of the second performance level of the secondary battery system according to Embodiment 1. As shown in Figure 3, in operation at the second characteristic level, an initial degradation estimation process (step S21) is first performed. In the initial degradation estimation process, the change in the battery resistance of the battery cell is calculated from the current and voltage values obtained when the battery cell assembled in step S15 is repeatedly charged and discharged multiple times, and a parameter that serves as an indicator of the degree of characteristic degradation of the battery cell is estimated based on the change in the battery resistance of the battery cell. By performing this initial degradation estimation process, it becomes possible to optimize the control of the battery cell according to the degradation state of the battery, making it possible to use the battery cell more safely and with higher performance. Details of the initial degradation estimation process will be described later.
[0026] Figure 4 shows a flowchart illustrating the flow of the initial degradation estimation process according to Embodiment 1. As shown in Figure 4, the initial degradation estimation process according to Embodiment 1 includes a current resistance measurement process (step S40), a characteristic degradation factor analysis process (step S41), and a salt concentration unevenness mitigation process (step S42). In the current resistance measurement process, charging and discharging are performed on the battery cell, and the current battery resistance of the battery cell is measured based on the charge / discharge current and the output voltage of the battery cell. In the characteristic degradation factor analysis process, the current value is estimated for each degradation factor parameter that is a characteristic degradation factor of the battery cell based on the difference between the battery resistance of a new battery cell estimated in advance and the current battery resistance measured in the current resistance measurement process. In the salt concentration unevenness mitigation process, the degradation factor parameter at that point is determined as a value when the current battery resistance measured after a certain period of charging and discharging, with the charge / discharge current limited to a preset charge / discharge rate, changes from decreasing to increasing, and the amount of change between the current battery resistance measured in the previous measurement and the current battery resistance measured in the current measurement falls within a preset range. Then, in the initial degradation estimation process, if the current battery resistance measured during the salt concentration unevenness mitigation process is lower than the current battery resistance measured in the previous measurement, the characteristic degradation factor analysis process is performed based on the newly measured current battery resistance.
[0027] Next, in the method of using the secondary battery system according to Embodiment 1, a battery parameter estimation process is performed to estimate battery parameters from the measurement results of the external dimensions of the secondary battery (measurement results from step S14) (step S22). In the battery parameter estimation process, after measuring the dimensions of the battery cell determined to be the target battery type, the battery cell is assembled into a state where it can be charged and discharged, and the degree of degradation of the battery cell and the current electrode capacity, which is the current electrode capacity of the battery cell, are estimated based on the charge / discharge current value and the output voltage value of the battery cell obtained by charging and discharging performed on the assembled battery cell, and the thickness of the active material layer of the battery cell is estimated based on the measurement results of the dimensions of the battery cell.
[0028] Here, the battery parameter estimation process will be explained in more detail. In the battery parameter estimation process, the provisional values obtained in step S12 and the measured values obtained in step S14 are used to estimate the characteristics of a new battery cell (e.g., capacity) and design parameters that indicate the structure of the battery cell. In other words, the battery characteristic estimation process obtains the characteristics of a new battery cell (e.g., capacity) and design parameters that indicate the structure of the battery cell without destroying the battery cell. Here, Figure 5 shows a flowchart illustrating the flow of the battery parameter estimation process according to Embodiment 1. As shown in Figure 5, the battery parameter estimation process performs a provisional parameter setting process (step S50), a current measurement process (step S51), a coating structure calculation process (step S52), and an active material thickness calculation process (step S53).
[0029] In the provisional parameter setting process, for example, the aluminum foil thickness, copper foil thickness, separator thickness, positive electrode density, positive electrode ratio capacity, negative electrode density, negative electrode ratio capacity, initial positive electrode capacity, and initial negative electrode capacity are set to provisional values by referring to the standard parameters entered in step S12.
[0030] In the current measurement process, the battery cell is charged and discharged while controlling it using the provisional values set in the provisional parameter setting process, and the degree of degradation of the battery cell, as well as the current electrode capacity of the battery cell, namely the current positive electrode capacity and the current negative electrode capacity, are estimated.
[0031] In the coating structure calculation process, the cross-sectional area of the electrode body housed in the battery cell, as viewed from the side perpendicular to the electrode stacking direction, and the width of the coating portion of the electrode body are calculated based on dimensions that can be measured without damaging the battery cell (for example, the width, height, and thickness of the case housing the electrode body in the battery cell obtained in step S14).
[0032] In the active material thickness calculation process, the thickness of the positive electrode active material layer and the thickness of the negative electrode active material layer are calculated using the aluminum foil thickness, copper foil thickness, separator thickness, positive electrode density, positive electrode specific capacity, negative electrode density, and negative electrode specific capacity, for which provisional values were set in the provisional parameter setting process in step S50, the current positive electrode capacity and current negative electrode capacity, for which estimated values were calculated in the current measurement process in step S51, and the cross-sectional area of the electrode body and the width of the coated part of the electrode body, for which the coated part structure calculation process in step S52 was calculated.
[0033] Next, in the battery system according to Embodiment 1, the battery parameters calculated in the battery parameter estimation process in step S22 are applied to the state estimation model (step S23), and the upper and lower voltage limits are updated to a voltage that is more relaxed than the upper and lower voltage limits set in step S16, based on the battery voltage estimated by the state estimation model (step S24). After that, in the secondary battery system according to Embodiment 1, while performing charge and discharge operations (step S25), the charge rate estimation process is performed (step S26), and the input and output power is limited based on the estimated charge rate (step S27). Then, in the secondary battery system according to Embodiment 1, if operation at the second performance level is specified (the NO branch of step Sb), the charge and discharge operations in steps S25 to S27 are continued. On the other hand, in the secondary battery system according to Embodiment 1, if operation at the third performance level is specified (the YES branch of step Sb), the control of the secondary battery is shifted to the third performance level (step S3).
[0034] Figure 6 shows a flowchart illustrating the operation flow of the third performance level of the secondary battery system according to Embodiment 1. As shown in Figure 6, in operation of the third performance level, the charge / discharge current, battery voltage, and battery temperature of the secondary battery are measured, and the measured charge / discharge current, battery voltage, and battery temperature are input to the state estimation model to perform state of charge (SOC) estimation processing and state of health (SOH) estimation processing (step S30). Subsequently, the secondary battery system according to Embodiment 1 performs automatic battery parameter fitting processing to update the battery parameters so as to reduce the difference between the estimated battery voltage calculated in the charge rate estimation processing and the actually measured battery voltage (step S31). Here, the magnitude of the difference between the estimated battery voltage and the actually measured battery voltage can be considered as one of the indicators of the degree of fit of the state estimation model or the battery parameters. For example, the smaller the difference between the estimated battery voltage and the actually measured battery voltage, the higher the degree of fit can be considered.
[0035] Next, in the secondary battery system according to Embodiment 1, it is determined whether or not the battery parameters necessary to enable suppression control have been extracted (step S32). For example, in step S32, if the degree of suitability of the battery parameters is above a preset threshold, it is determined that the battery parameters necessary to enable suppression control have been extracted, and if the degree of suitability of the battery parameters is below a preset threshold, it is determined that the extraction of battery parameters necessary to enable suppression control is incomplete. In the example in Figure 6, two types of suppression control are shown: lithium deposition suppression control and life prediction processing. However, suppression control is not limited to these two, as long as it is a control that suppresses the input / output power of the secondary battery below the maximum power of the secondary battery.
[0036] If it is determined in step S32 that battery parameters have not been extracted, a power limit update process is performed to update the set value with upper and lower voltage limits corresponding to the current state of the secondary battery, based on the result of the charge rate estimation process in step S30 (step S37). On the other hand, if battery parameters have been extracted in step S32, the secondary battery system according to Embodiment 1 determines whether or not a request for lithium deposition suppression control has been instructed by the user (step S33). If there is a request for lithium deposition suppression control (the YES branch in step S33), lithium deposition suppression control is enabled, and lithium deposition suppression control is implemented in the subsequent processing (step S34). On the other hand, if there is no request for lithium deposition suppression control (the NO branch in step S33), lithium deposition suppression control remains disabled.
[0037] Furthermore, it is determined whether or not a request for life prediction processing has been issued by the user (step S35). If a request for life prediction processing is issued (the YES branch in step S35), the life prediction processing is enabled and the life prediction processing is carried out in subsequent processing (step S36). On the other hand, if there is no request for life prediction processing (the NO branch in step S35), the life prediction processing remains disabled.
[0038] Furthermore, after the processing in steps S33 to S36 is completed, the processing in step S37 is performed. Then, if the life prediction processing was enabled in step S36, the life prediction processing is performed after the power limit update in step S37 (step S38). After that, the processing in steps S30 to S39 is repeated until the life of the secondary battery is exhausted (YES branch in step S39). On the other hand, once the life of the secondary battery is exhausted, the use of the battery is terminated.
[0039] As described above, the method of using the secondary battery system according to Embodiment 1 allows for the immediate determination of an output limit suitable for the application using the secondary battery, while simultaneously applying control of the processing load appropriate for that application. Furthermore, the method of using the secondary battery system according to Embodiment 1 allows for improved accuracy in estimating the battery state while using the secondary battery.
[0040] Furthermore, in the control of secondary batteries, suppression control is performed to extend lifespan or ensure stable control. However, during periods when the fit of the state estimation model or battery parameters is low, stronger suppression control may be applied to the actual performance of the secondary battery. In contrast, in the secondary battery system according to Embodiment 1, suppression control is disabled until the fit improves, so the output performance of the secondary battery is not reduced by stronger suppression control than intended. In other words, in the secondary battery system according to Embodiment 1, the maximum performance of the battery can be extracted while in use.
[0041] It should be noted that the present invention is not limited to the embodiments described above, and can be modified as appropriate without departing from the spirit of the invention.
Claims
1. A state estimation process that acquires the charge / discharge current, battery voltage, and temperature of a secondary battery to estimate the charge level and state of the secondary battery, An automatic fitting process that updates the battery parameters applied to the state estimation model used in the state estimation process to match the current state of the secondary battery, A suppression control process is performed to extend the lifespan of the secondary battery by limiting its output based on the estimation results using the state estimation model, and this is carried out by an automatic calculation process performed by a computer. The suppression control process is a battery control method that suppresses execution until the battery parameters show a degree of fit equal to or greater than a preset threshold.
2. The battery control method according to claim 1, wherein the suppression control is kept in an inactive state and does not execute processing unless an activation instruction is given from the outside.
3. The suppression control process includes: Lithium deposition suppression control that suppresses the charge / discharge current to the secondary battery in order to suppress the amount of lithium deposition of the secondary battery estimated using the state estimation model, The process for estimating the lifespan of the secondary battery, which is estimated using the state estimation model, The battery control method according to claim 1, which includes at least one of the following.
4. A state estimation process that acquires the charge / discharge current, battery voltage, and temperature of a secondary battery to estimate the charge level and state of the secondary battery, An automatic fitting process that updates the battery parameters applied to the state estimation model used in the state estimation process to match the current state of the secondary battery, A suppression control process is performed by a computer to implement suppression control that limits the output of the secondary battery to extend its lifespan based on the estimation results using the state estimation model, and this process is performed by a computer. The suppression control process is a battery control program that suppresses execution until the battery parameters show a degree of fit equal to or greater than a preset threshold.
5. Operation at a first performance level involves applying pre-set standard parameters based on the battery type of the secondary battery, and applying pre-set upper and lower voltage limits based on the battery type of the secondary battery to perform the charge and discharge operation. While performing a charge rate estimation process by applying battery parameters calculated based on the degradation state of the secondary battery to a state estimation model, the operation at a second performance level involves applying upper and lower voltage limits according to the degradation state of the secondary battery calculated by the state estimation model, and input / output power limits according to the charge rate of the secondary battery to perform the charge / discharge operation. Operation at a third performance level involves applying the power limit value calculated by the secondary battery state estimation process and the automatic adaptation process that updates the battery parameters to match the current state of the secondary battery, to perform charging and discharging operations according to the state of the secondary battery. A method for using a secondary battery system, wherein the secondary battery is operated by specifying one of the first performance level, the second performance level, and the third performance level, In operation at the aforementioned third performance level, The state estimation process involves acquiring the charge / discharge current, battery voltage, and temperature of the secondary battery to estimate the charge level and state of the secondary battery, The automatic fitting process updates the battery parameters applied to the state estimation model used in the state estimation process to match the current state of the secondary battery, A suppression control process is performed by a computer to implement suppression control that limits the output of the secondary battery to extend its lifespan based on the estimation results using the state estimation model, and this process is performed by a computer. The suppression control process is a method for using a secondary battery system in which the execution of the suppression control process is suppressed until the battery parameters show a degree of fit equal to or greater than a preset threshold.