Battery control method, battery control program, and method for using secondary battery system

Abstract

Conventional battery control methods have a problem that reuse that sufficiently exerts the performance of a secondary battery cannot be performed. This battery control method implements a state estimation process (S30), an automatic adaptation process (S31), and a suppression control process (S32-S36) by means of an automatic calculation process by a computer, wherein the state estimation process (S30) is a process for acquiring a charge / discharge current, a battery voltage, and a temperature of a secondary battery and estimating a charge rate and a state of the secondary battery; the automatic adaptation process (S31) is a process for updating a battery parameter adapted to the state estimation model used in the state estimation process (S30) so as to adapt to the state of the current secondary battery. The suppression control process (S32-S36) is a process for performing suppression control for extending the life of the secondary battery by limiting the output of the secondary battery on the basis of the estimation result by the state estimation model, and the suppression control process (S32-S36) suppresses execution until the battery parameter shows a fitness equal to or greater than a preset threshold value.

Description

Technical Field

[0001] This invention relates to a battery control method, a battery control program, and a method of utilizing a secondary battery system, such as a system utilizing a manufacturing process or a secondary battery with an unknown history. Background Technology

[0002] In recent years, efforts have begun to recycle secondary batteries that have reached the end of their intended use for other purposes. However, when using secondary batteries, if the battery parameters used to monitor the battery's condition cannot be controlled, problems such as overcharging and over-discharging can lead to unstable battery control. Therefore, Japanese Patent Application Publication No. 2009-080093 discloses a technology for monitoring the degradation state of secondary batteries.

[0003] The method for detecting internal information of a secondary battery as described in Japanese Patent Application Publication No. 2009-080093 comprises: a first step of acquiring inherent charge-discharge curves of a positive electrode material and inherent charge-discharge curves of a negative electrode material as basic data, and acquiring a measured charge-discharge curve of the battery under test; a second step of using the inherent charge-discharge curves of the positive electrode material, the inherent charge-discharge curves of the negative electrode material, the measured charge-discharge curve of the battery under test, and a predetermined correction parameter to calculate the charge-discharge curves of the positive electrode and the negative electrode inside the battery under test; and a third step of outputting the charge-discharge curves of the positive electrode and the negative electrode obtained in the second step, and at least one of the correction parameters used for calculation. Summary of the Invention

[0004] However, the technology described in Japanese Patent Application Publication No. 2009-080093 has the following problem: the technology can only be used after data on the performance inconsistencies of new products, including the performance of old batteries, are obtained through testing, and the only way to address the performance inconsistencies is to suppress the actual battery performance.

[0005] The present invention was made in view of the above circumstances, and its object is to promote the reuse of secondary batteries with unknown properties to fully utilize their performance.

[0006] One aspect of the battery control method involved in this invention is to implement state estimation processing, automatic adaptation processing, and suppression control processing through computer-based automatic calculation processing. The state estimation processing involves obtaining the charging and discharging current, battery voltage, and temperature of the secondary battery to estimate the charging rate and state of the secondary battery. The automatic adaptation processing involves updating the battery parameters of the state estimation model used in the state estimation processing to make them suitable for the current state of the secondary battery. The suppression control processing involves implementing suppression control, which is based on using the estimation results of the state estimation model to limit the output of the secondary battery to extend the life of the secondary battery. The suppression control processing is executed until the battery parameters show a fit level above a preset threshold.

[0007] One aspect of the battery control program involved in this invention is that a computer performs state estimation processing, automatic adaptation processing, and suppression control processing. The state estimation processing involves acquiring the charging and discharging current, battery voltage, and temperature of the secondary battery to estimate its charging rate and state. The automatic adaptation processing involves updating the battery parameters of the state estimation model used in the state estimation processing to suit the current state of the secondary battery. The suppression control processing involves implementing suppression control, which is based on using the estimation results of the state estimation model to limit the output of the secondary battery and extend its lifespan. The suppression control process is executed until the battery parameters show a fit level above a preset threshold.

[0008] One method of utilizing the secondary battery system involved in this invention involves setting up operation at a first performance level, an operation at a second performance level, and an operation at a third performance level. The first performance level operation applies pre-set standard parameters based on the battery type of the secondary battery, and applies pre-set upper and lower limit voltages based on the battery type for charging and discharging operations. The second performance level operation involves applying battery parameters calculated based on the degradation state of the secondary battery to a state estimation model for charge rate estimation processing, while simultaneously applying upper and lower limit voltages corresponding to the degradation state of the secondary battery, and input / output power limits corresponding to the charge rate of the secondary battery for charging and discharging operations. The degradation state of the secondary battery is calculated by the state estimation model. The third performance level operation applies power limit values ​​to perform charging and discharging operations corresponding to the state of the secondary battery. The power limit values ​​are calculated through the state estimation processing and automatic adaptation processing of the secondary battery. The optimization process is a process of updating the battery parameters to suit the current state of the secondary battery. The utilization method is a method of utilizing a secondary battery system by specifying any one of the first performance level, the second performance level, and the third performance level. In the application of the third performance level, the computer performs the state estimation process, the automatic adaptation process, and the suppression control process. The state estimation process is a process of estimating the charge rate and state of the secondary battery by acquiring the charge and discharge current, battery voltage, and temperature of the secondary battery. The automatic adaptation process is a process of updating the battery parameters applicable to the state estimation model used in the state estimation process to suit the current state of the secondary battery. The suppression control process is a process of implementing suppression control. The suppression control is based on using the estimation results of the state estimation model to limit the output of the secondary battery to extend the life of the secondary battery. The suppression control process suppresses execution until the battery parameters show a suitability of more than a preset threshold.

[0009] The battery control method, battery control program, and utilization method of the secondary battery system according to the present invention can promote the reuse of secondary batteries with unknown properties to fully utilize their performance. Attached Figure Description

[0010] Figure 1 This is a flowchart illustrating the method of utilizing the secondary battery system according to Embodiment 1.

[0011] Figure 2 This is a flowchart illustrating the application of the first performance level of the secondary battery system involved in Implementation Method 1.

[0012] Figure 3 This is a flowchart illustrating the application of the second performance level of the secondary battery system involved in Implementation Method 1.

[0013] Figure 4 This is a flowchart illustrating the process of the initial degradation estimation process involved in Implementation Method 1.

[0014] Figure 5 This is a flowchart illustrating the process of estimating battery parameters involved in Implementation Method 1.

[0015] Figure 6 This is a flowchart illustrating the application of the third performance level of the secondary battery system involved in Implementation Method 1. Detailed Implementation

[0016] For clarity, the following descriptions and figures have been appropriately omitted and simplified. Furthermore, the elements described in the figures as functional blocks performing various processes can, from a hardware perspective, be constituted by a CPU (Central Processing Unit), memory, and other circuitry; from a software perspective, they can be implemented by programs loaded into memory, etc. Therefore, those skilled in the art will understand that these functional blocks can be implemented in various forms, by hardware alone, software alone, or a combination thereof, and are not limited to any one of them. It should be noted that the same symbols are used for the same elements in the figures, and repeated descriptions are omitted as necessary.

[0017] Furthermore, when the aforementioned program is read into a computer, it includes a group of commands (or software code) for causing the computer to perform one or more functions described in the implementation method. The program may also be stored on a non-transitory computer-readable medium or a physical storage medium. As a non-limiting example, a computer-readable medium or a physical storage medium includes random-access memory (RAM), read-only memory (ROM), flash memory, solid-state drive (SSD), or other storage technologies; compact disc read-only memory (CD-ROM), digital versatile disc (DVD), Blu-ray disc, or other optical disc storage; magnetic tape, magnetic tape, disk storage, or other magnetic storage devices. The program can be transmitted on a transient computer-readable medium or a communication medium. As a non-limiting example, a transient computer-readable medium or communication medium includes electrical, optical, acoustic, or other forms of propagated signals.

[0018] It should be noted that the method of utilizing the secondary battery system described in Embodiment 1 below is carried out through automatic processing by one or more programs executed on a computer, such as an electronic control unit (ECU) that controls the charging and discharging of the secondary battery.

[0019] Implementation Method 1 In the following description, a method for utilizing a secondary battery system that reuses a secondary battery will be explained. Furthermore, in the method of utilizing the battery according to Embodiment 1, regardless of whether the purpose of using the secondary battery is a battery pack consisting of multiple batteries, the term "battery unit" is used in the description because battery parameters and performance are evaluated on a per-cell basis. Additionally, in the method of utilizing the secondary battery system according to Embodiment 1, although there are no restrictions on the type of secondary battery, a lithium-ion secondary battery will be described as the specific type used.

[0020] In the utilization method of the secondary battery system according to Embodiment 1, even battery cells with unclear attributes and difficult-to-obtain information related to their design and manufacturing can be recycled. Furthermore, in the utilization method of the secondary battery system according to Embodiment 1, since the accuracy of information regarding the current characteristics of the battery cell is gradually improved while it is being used for a specific purpose, the period of unused battery cells can be shortened. The utilization method of the secondary battery system according to Embodiment 1 will be described in detail below.

[0021] exist Figure 1 The flowchart illustrates the method of utilizing the secondary battery system according to Embodiment 1. Figure 1 As shown, in the secondary battery system according to Embodiment 1, the secondary battery is used by specifying any one of three performance levels. For example, if the use at the first performance level is specified (step S1), the use at the first performance level in step S1 continues. If the use at the second performance level is specified (step S2), after using the first performance level in step S1 once, the battery system transitions to using the second performance level in step S2. Furthermore, if the use at the third performance level is specified (step S3), after using the first performance level in step S1 and the second performance level once each, the battery system transitions to using the third performance level in step S3. Figure 1 In the diagram, steps Sa and Sb are shown as determination processes for deciding which performance level to apply the battery to. Furthermore, in the application at the third performance level, step Sc is shown, which determines whether the secondary battery has reached its lifespan in order to terminate its use based on whether the battery has reached its lifespan.

[0022] Here, the application of the first, second, and third performance levels will be explained. The first performance level is applied based on the type of secondary battery, using pre-set standard parameters and pre-set upper and lower voltage limits for charging and discharging operations. For example, with a ternary lithium-ion secondary battery, the first performance level is used to set a lower voltage limit of 3V and an upper voltage limit of 4.2V, performing battery control such as estimating the charging rate based on the battery voltage.

[0023] The second performance level application involves applying battery parameters calculated based on the secondary battery's degradation state to a state estimation model for charge rate estimation, while simultaneously setting upper and lower limit voltages corresponding to the secondary battery's degradation state calculated by the state estimation model, and limiting the input and output power corresponding to the secondary battery's charge rate to perform charge and discharge operations. For example, in the second performance level application, battery control is performed to correct the charge rate estimated by current integration, such as estimating the open circuit voltage (OCV) as the release voltage from the measured voltage. Because the second performance level application extracts the control parameters used for the secondary battery with higher accuracy, it is suitable for applications requiring a certain level of estimation in upper and lower limit voltage or charge rate estimation.

[0024] The application of the third performance level involves using power limits to perform charge and discharge operations corresponding to the state of the secondary battery. These power limits are calculated through a state estimation process and an automatic adaptation process, whereby battery parameters are updated to suit the current state of the secondary battery. For example, in the third performance level application, lifetime, lithium deposition suppression, power limits, etc., are calculated from the acquired battery parameters and controlled more precisely. Because the third performance level application can calculate the secondary battery's lifetime and the power limits that maximize its performance, information derived from charge and discharge operations can be reflected in the battery model.

[0025] The following sections will provide a detailed explanation of the applications from the first performance level to the third performance level. Firstly, in... Figure 2 A flowchart illustrating the application of the first performance level of the secondary battery system according to Embodiment 1 is shown. Figure 2 As shown, in applications at the first performance level, regardless of whether the attributes of the battery cell are clear, product information of the battery cell is input (step S11). Specifically, in the method for utilizing a secondary battery system according to Embodiment 1, in step S11, information about the type of battery, including at least the battery cell to be used, is input into the computer as product information. Here, in secondary batteries, depending on the type of active material used, there are lead-acid batteries, nickel-metal hydride batteries, lithium-ion batteries, etc. Therefore, in the method for utilizing a secondary battery system according to Embodiment 1, information about which material the battery cell to be used is made of, such as lead-acid, nickel-metal hydride, or lithium-ion, is provided to the computer as the battery type.

[0026] Next, in step S12, standard parameters pre-set for each type of battery cell to be used are temporarily determined as battery parameters. Here, the standard parameters in the method for utilizing the secondary battery system according to Embodiment 1 refer to values ​​pre-determined by the operator reusing the battery cells based on information generally disclosed, such as information published on the homepages of material suppliers for the battery cells. For example, 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.

[0027] Next, in step S13, it is determined whether the secondary battery can be used. 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 visual problems such as leakage. If the secondary battery is normal (usable), the next step S14 is performed. On the other hand, if a problem is found in the secondary battery in step S13, the use of that secondary battery is terminated.

[0028] In step S13, step S14, which measures the size of the usable secondary battery, and step S15, which assembles the secondary battery into a rechargeable state, are performed. Thereafter, in operation at the first performance level, a pre-set upper and lower limit voltage is set based on the battery parameters temporarily set in step S12 according to the battery type, and a charging / discharging operation is performed while applying input / output power limits derived from these upper and lower limit voltages (step S16). Next, 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 / discharging operation of step S16 continues. 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).

[0029] exist Figure 3 The diagram shows a flowchart illustrating the application of the second performance level of the secondary battery system according to Embodiment 1. (See attached diagram.) Figure 3 As shown, in the application of the second performance level, an initial degradation estimation process is first implemented (step S21). In this initial degradation estimation process, the change in battery resistance of the battery cell is calculated by repeatedly charging and discharging the battery cell assembled in step S15, using the current and voltage values ​​obtained from these measurements. Based on this change in battery resistance, a parameter representing the degree of degradation of the battery cell's characteristics is estimated. By performing this initial degradation estimation process, the control of the battery cell can be optimized according to the battery's degradation state, allowing for safer and higher-performance utilization of the battery cell. Details of the initial degradation estimation process will be described later.

[0030] exist Figure 4 The diagram shows a flowchart illustrating the process of the initial degradation estimation process involved in Implementation 1. For example... Figure 4As shown, in the initial degradation estimation process according to Embodiment 1, the following steps are performed: current resistance value measurement (step S40), characteristic degradation cause analysis (step S41), and salt concentration unevenness mitigation (step S42). In the current resistance value measurement process, the battery cell is charged and discharged, and the current battery resistance of the battery cell is measured based on the charging / discharging current and the output voltage of the battery cell. In the characteristic degradation cause analysis process, the current value of the degradation factor parameter, which is a characteristic degradation factor of the battery cell, is estimated based on the difference between the battery resistance of the battery cell in a pre-estimated new product state and the current battery resistance measured in the current resistance value measurement process. In the salt concentration unevenness mitigation process, the current battery resistance measured after a certain period of charging / discharging treatment with the charging / discharging current limited to a pre-set charging / discharging rate changes from decreasing to increasing, and the change in the current battery resistance between the previous measurement and the current measurement falls within a pre-set certain range; at this point, the degradation factor parameter is set to a fixed value. Furthermore, 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, a characteristic degradation cause analysis process is performed based on the newly measured current battery resistance.

[0031] Next, in the method for utilizing the secondary battery system according to Embodiment 1, a battery parameter estimation process (step S22) is performed to estimate battery parameters based on the external dimension measurement results of the secondary battery (the measurement results of step S14). In the battery parameter estimation process, the degradation degree 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. The charge / discharge current value and the output voltage value of the battery cell are obtained by measuring the size of the battery cell that is determined to be the target battery type, assembling the battery cell into a charge / dischargeable state, and performing charge and discharge operations on the assembled battery cell. At the same time, the thickness of the active material layer of the battery cell is estimated based on the size measurement results of the battery cell.

[0032] Here, the battery parameter estimation process will be explained in more detail. In this process, the provisional values ​​obtained in step S12 and the measured values ​​obtained in step S14 are used to estimate the characteristics of the battery cell in its new state (e.g., capacity) and the design parameters representing the battery cell's structure. In other words, the battery parameter estimation process obtains the characteristics of the battery cell in its new state (e.g., capacity) and the design parameters representing the battery cell's structure without damaging the battery cell. Here, in Figure 5 The document shows a flowchart illustrating the battery parameter estimation process involved in Embodiment 1. (See attached diagram.) Figure 5As shown, in the battery parameter estimation process, provisional parameter setting process (step S50), current status measurement process (step S51), coating part structure calculation process (step S52), and active material thickness calculation process (step S53) are performed.

[0033] In the provisional parameter setting process, referring to the standard parameters input in step S12, provisional values ​​are set for each parameter, such as aluminum foil thickness, copper foil thickness, separator thickness, positive electrode density, positive electrode specific capacity, negative electrode density, negative electrode specific capacity, initial positive electrode capacity, and initial negative electrode capacity.

[0034] In the current status measurement process, while controlling the battery cell using the provisional values ​​set by the provisional parameter setting process, the battery cell is charged and discharged to estimate the degree of degradation of the battery cell and the current positive electrode capacity and current negative electrode capacity, which are the current electrode capacities of the battery cell.

[0035] In the coating section structure calculation process, the cross-sectional area observed from the side orthogonal to the electrode stacking direction of the electrode body housed in the battery cell and the coating section width of the electrode body are calculated based on the dimensions that can be measured without damaging the battery cell (e.g., the width, height, and thickness of the housing of the electrode body in the battery cell obtained in step S14).

[0036] In the active material thickness calculation process, the aluminum foil thickness, copper foil thickness, separator thickness, positive electrode density, positive electrode specific capacity, negative electrode density, and negative electrode specific capacity are used as provisional values ​​set in the provisional parameter setting process in step S50. The estimated current positive electrode capacity and current negative electrode capacity are calculated in the current status measurement process in step S51. The cross-sectional area of ​​the electrode body and the width of the coating part of the electrode body are calculated in the coating part structure calculation process in step S52. The thickness of the positive electrode active material layer and the thickness of the negative electrode active material layer are then calculated.

[0037] 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 limits derived from the upper and lower limit voltages are updated to a more moderate voltage than the upper and lower limit voltages set in step S16 based on the battery voltage estimated by the state estimation model (step S24). Thereafter, in the secondary battery system according to Embodiment 1, while performing charging and discharging operations (step S25), a charging rate estimation process is performed (step S26), and the input and output power is limited based on the estimated charging rate value (step S27). Next, in the secondary battery system according to Embodiment 1, if the application at the second performance level is specified (the "No" branch of step Sb), the charging and discharging operations of steps S25 to S27 continue. On the other hand, in the secondary battery system according to Embodiment 1, if the application 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).

[0038] exist Figure 6 The diagram shows a flowchart illustrating the application of the third performance level of the secondary battery system according to Embodiment 1. (See attached diagram.) Figure 6 As shown, in the application of the third performance level, the charging and discharging current, battery voltage, and battery temperature of the secondary battery are measured, and the measured charging and discharging current, battery voltage, and battery temperature are input into the state estimation model to perform state of charge (SOC) estimation processing and state of health (SOH) estimation processing (step S30). Next, the secondary battery system according to Embodiment 1 performs automatic battery parameter fitting processing (step S31), which updates the battery parameters by reducing the difference between the estimated battery voltage calculated in the charge rate estimation processing and the actual measured battery voltage. Here, the magnitude of the difference between the estimated battery voltage and the actual measured battery voltage can be regarded as one of the indicators of the fit of the state estimation model or battery parameters. For example, the smaller the difference between the estimated battery voltage and the actual measured battery voltage, the higher the fit can be considered.

[0039] Next, in the secondary battery system according to Embodiment 1, it is determined whether the extraction of battery parameters for effective suppression control is complete (step S32). For example, in step S32, if the fitness of the battery parameters is above a preset threshold, it can be determined that the extraction of battery parameters for effective suppression control is complete; if the fitness of the battery parameters is below the preset threshold, it can be determined that the extraction of battery parameters for effective suppression control is incomplete. It should be noted that, although in Figure 6The examples show two types of suppression control: lithium deposition suppression control and lifetime prediction processing. However, suppression control is not limited to these two types as long as it suppresses the input and output power of the secondary battery from being greater than the maximum power of the secondary battery.

[0040] If, in step S32, it is determined that the extraction of battery parameters is incomplete, a power limit update process is performed (step S37), which updates the set values ​​based on the upper and lower limit voltages corresponding to the current state of the secondary battery, according to the result of the charge rate estimation process in step S30. On the other hand, if the extraction of battery parameters is complete in step S32, in the secondary battery system according to Embodiment 1, it is determined whether a user has indicated a requirement for lithium deposition suppression control (step S33). Then, if there is a requirement for lithium deposition suppression control (the "yes" branch of step S33), lithium deposition suppression control is enabled, and lithium deposition suppression control is implemented in subsequent processing (step S34). On the other hand, if there is no requirement for lithium deposition suppression control (the "no" branch of step S33), lithium deposition suppression control is maintained as disabled.

[0041] Furthermore, it is determined whether a user has indicated a request for lifetime prediction processing (step S35). Next, if a request for lifetime prediction processing exists (the "Yes" branch of step S35), the lifetime prediction processing is enabled and implemented in subsequent processes (step S36). On the other hand, if there is no request for lifetime prediction processing (the "No" branch of step S35), the lifetime prediction processing remains disabled.

[0042] Furthermore, after the processing in steps S33 to S36 is completed, the processing in step S37 is performed. Subsequently, if the lifetime prediction processing in step S36 is effective, lifetime prediction processing is performed after the power limit update in step S37 (step S38). Then, the processing in steps S30 to S39 (the "Yes" branch of step S39) is repeated until the secondary battery's lifetime is exhausted. Alternatively, if the secondary battery's lifetime is exhausted, battery utilization is terminated.

[0043] From the above description, the method for utilizing a secondary battery system according to Embodiment 1 can immediately determine the output limits suitable for the application of the secondary battery, and simultaneously apply control to the processing load suitable for that application. Furthermore, the method for utilizing a secondary battery system according to Embodiment 1 can improve the accuracy of battery state estimation while utilizing the secondary battery.

[0044] Furthermore, in the control of secondary batteries, suppression control is sometimes implemented to extend battery life or achieve stable control. During periods when the fitness of the state estimation model or battery parameters is low, there are instances where strong suppression control is applied to the actual capability of the secondary battery. However, in the secondary battery system described in Embodiment 1, since the suppression control is ineffective until the fitness increases, the output capability of the secondary battery is not weakened due to stronger suppression control than desired. In other words, in the secondary battery system described in Embodiment 1, the battery performance can be maximized during use.

[0045] It should be noted that the present invention is not limited to the above embodiments, and appropriate modifications can be made without departing from the spirit of the invention.

Claims

1. A battery control method, characterized in that, The battery control method implements state estimation processing, automatic adaptation processing, and suppression control processing through computer-based automatic calculation processing. The state estimation process is a process of estimating the charging rate and state of the secondary battery by obtaining the charging and discharging current, battery voltage, and temperature of the secondary battery. The automatic adaptation process is a process of updating the battery parameters of the state estimation model used in the state estimation process in a way that makes them suitable for the current state of the secondary battery. The suppression control process is a process of implementing suppression control, which is based on using the estimation results of the state estimation model to limit the output of the secondary battery and thus extend the life of the secondary battery. The suppression control process is executed until the battery parameters show a fitness level above a preset threshold.

2. The battery control method according to claim 1, wherein, The suppression control maintains an invalid state where no processing is performed in the absence of an external indication of validation.

3. The battery control method according to claim 1, wherein, The suppression and control process includes at least one of lithium deposition suppression control and the secondary battery lifetime prediction process. The lithium deposition suppression control suppresses the charge and discharge current to the secondary battery in a manner that suppresses the amount of lithium deposition estimated by the state estimation model. The lifetime prediction process for the secondary battery is performed using the state estimation model.

4. A battery control program, characterized in that, The battery control program enables the computer to perform state estimation processing, automatic adaptation processing, and suppression control processing. The state estimation process is a process of estimating the charging rate and state of the secondary battery by obtaining the charging and discharging current, battery voltage, and temperature of the secondary battery. The automatic adaptation process is a process of updating the battery parameters of the state estimation model used in the state estimation process in a way that makes them suitable for the current state of the secondary battery. The suppression control process is a process of implementing suppression control, which is based on using the estimation results of the state estimation model to limit the output of the secondary battery and thus extend the life of the secondary battery. The suppression control process is executed until the battery parameters show a fitness level above a preset threshold.

5. A method for utilizing a secondary battery system, characterized in that, The method for utilizing the secondary battery system involves specifying three performance levels: a first performance level, a second performance level, and a third performance level, and then designating any one of these three performance levels to utilize the secondary battery. The application of the first performance level is based on the type of secondary battery and applies preset standard parameters, and applies preset upper and lower limit voltages to perform charging and discharging operations based on the type of secondary battery. The application of the second performance level involves applying the battery parameters calculated based on the degradation state of the secondary battery to the charging rate estimation process of the state estimation model, while simultaneously applying the setting of upper and lower limit voltages corresponding to the degradation state of the secondary battery and the limitation of input and output power corresponding to the charging rate of the secondary battery to perform charging and discharging operations. The degradation state of the secondary battery is the degradation state of the secondary battery calculated by the state estimation model. The application of the third performance level involves using a power limit value to perform charging and discharging operations corresponding to the state of the secondary battery. This power limit value is calculated through state estimation and automatic adaptation processing of the secondary battery. The automatic adaptation processing updates the battery parameters to adapt them to the current state of the secondary battery. In the application of the third performance level, the computer performs the state estimation processing, the automatic adaptation processing, and the suppression control processing. The state estimation process is a process of estimating the charging rate and state of the secondary battery by obtaining the charging and discharging current, battery voltage, and temperature of the secondary battery. The automatic adaptation process is a process of updating the battery parameters of the state estimation model used in the state estimation process in a way that makes them suitable for the current state of the secondary battery. The suppression control process is a process of implementing suppression control, which is based on using the estimation results of the state estimation model to limit the output of the secondary battery and thus extend the life of the secondary battery. The suppression control process is executed until the battery parameters show a fitness level above a preset threshold.

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