Estimation device, estimation program, and estimation method

Abstract

To provide an estimation device, an estimation program, and an estimation method that can improve the accuracy of estimating the SOC of a bound battery pack.SOLUTION: An estimation device 10 comprises: a battery information acquisition unit 130 that acquires battery information of a battery pack; and an estimated value calculation unit 131 that calculates a SOC that is an estimated value of the battery pack by using the battery information and the state estimation model for the battery pack. The battery information includes the already-calculated SOC of the battery pack, a binding state value a∼ depending on the state of binding of the battery pack, and a measured current value of the battery pack. The state estimation model uses the already-calculated SOC, the already-calculated binding state value a∼, and the measured current value of the battery pack as input information, and uses the SOC of the battery pack and the binging state value a∼ as output information.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to an estimation device, an estimation program, and an estimation method for estimating the State Of Charge (SOC) of a secondary battery.

Background Art

[0002] Currently, in vehicles that use electric power as a driving force, such as electric vehicles, hybrid vehicles, and plug-in hybrid vehicles, secondary batteries such as lithium-ion batteries and nickel-metal hydride batteries are used. As an example of a technique for estimating the SOC of such a secondary battery, Patent Document 1 discloses a method of detecting a volume change of at least one of a positive electrode and a negative electrode, detecting a temperature of at least one of the positive electrode and the negative electrode, and estimating the SOC, which is an estimated remaining capacity value of the secondary battery, from a preset correlation based on the detected volume change and temperature.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the method disclosed in Patent Document 1, there is a problem that the estimation accuracy of the SOC of the assembled battery is low because the SOC cannot be estimated in consideration of the restraint state of the assembled battery by the restraint member.

[0005] The present disclosure has been made to solve such problems, and an object thereof is to provide an estimation device, an estimation program, and an estimation method capable of improving the estimation accuracy of the SOC of a constrained assembled battery.

Means for Solving the Problems

[0006] An estimation device for estimating the SOC (State Of Charge) of a battery pack formed by restraining a plurality of secondary batteries according to the present disclosure, a battery information acquisition unit that acquires battery information of the battery pack, and an estimated value calculation unit that calculates the SOC, which is an estimated value of the battery pack, using the battery information acquired by the battery information acquisition unit and a state estimation model of the battery pack. The battery information includes the SOC of the battery pack that has already been calculated and a constraint state value a that depends on the state of restraint of the battery pack. ~ and the measured current value of the battery pack. The state estimation model uses the already calculated SOC, the already calculated constraint state value a, ~ and the measured current value of the battery pack as input information, and outputs the SOC and the constraint state value a of the battery pack. ~ as output information. The constraint state value a ~ is a value that depends on the non-expanded length a of the active material included in the battery pack, the spring constant k of the member disposed adjacent to the battery pack in the restraint direction of the battery pack and the active material, 1 and the spring constant k of the restraint member that restrains the battery pack from the restraint direction. 2

[0007] The constraint state value a ~ may correspond to a value obtained by dividing the product of the length a and the spring constant k 1 and the spring constant k 2 by the sum of the spring constant k 1 and the spring constant k. 2

[0008] An estimation device for estimating the SOC (State Of Charge) of a battery pack formed by restraining a plurality of secondary batteries according to the present disclosure, a battery information acquisition unit that acquires battery information of the battery pack, and an estimated value calculation unit that calculates the SOC, which is an estimated value of the battery pack, using the battery information acquired by the battery information acquisition unit and a state estimation model of the battery pack. The battery information includes the SOC of the battery pack that has already been calculated and a constraint state value a that depends on the state of restraint of the battery pack. ~ and the measured current value of the battery pack. The state estimation model uses the already calculated SOC, the already calculated constraint state value a ~ and the measured current value of the battery pack as input information, and outputs the SOC and the constraint state value a ~ of the battery pack. The constraint state value a ~ is a value that depends on the length a of the unexpanded active material included in the battery pack, the spring constant k of the member arranged adjacent to the battery pack in the constraint direction of the battery pack, 1 and the spring constant k of the detection spring arranged adjacent to the battery pack in the constraint direction. s It depends on the value of the spring constant k of the detection spring arranged adjacent to the battery pack in the constraint direction.

[0009] The constraint state value a ~ is the product of the spring constant k and the length a divided by the sum of the spring constant k 1 and the spring constant k 1 and may correspond to a negative value corresponding to the quotient. s It may correspond to a negative value corresponding to the quotient obtained by dividing the product of the spring constant k and the length a by the sum of the spring constant k and the spring constant k.

[0010] The estimated value calculation unit further calculates the constraint state value a ~ which is the estimated value of the secondary battery, using the state estimation model. The estimation device further includes an estimated value correction unit that corrects the SOC and the constraint state value a ~ calculated by the estimated value calculation unit, and the estimated value calculation unit may calculate the SOC of the battery pack by inputting the SOC and the constraint state value a ~ corrected by the estimated value correction unit into the state estimation model.

[0011] The state estimation model may be an equivalent circuit model or an electrochemical model.

[0012] An estimation method for estimating the SOC (State Of Charge) of a battery pack formed by constraining a plurality of secondary batteries according to the present disclosure includes a computer acquiring battery information of the battery pack, and calculating the SOC, which is the estimated value of the battery pack, using the acquired battery information and the state estimation model of the battery pack. The battery information includes the SOC of the assembled battery that has already been calculated and the constraint state value a that depends on the state of constraint of the assembled battery ~ and the measured current value of the assembled battery, The state estimation model uses the already calculated SOC, the already calculated constraint state value a ~ and the measured current value of the assembled battery as input information, and the SOC and constraint state value a of the assembled battery ~ as output information, The constraint state value a ~ is a value that depends on the non-expanded length a of the active material included in the assembled battery, the spring constant k of the member arranged adjacent to the assembled battery in the constraint direction of the assembled battery, and the spring constant k of the active material 1 and the spring constant k of the constraint member that constrains the assembled battery from the constraint direction 2 is a value that depends on

[0013] The estimation method for estimating the SOC (State Of Charge) of an assembled battery formed by constraining a plurality of secondary batteries according to the present disclosure is such that a computer acquires the battery information of the assembled battery, and calculates the SOC, which is an estimated value of the assembled battery, using the acquired battery information and the state estimation model of the assembled battery. The battery information includes the SOC of the assembled battery that has already been calculated and the constraint state value a that depends on the state of constraint of the assembled battery ~ and the measured current value of the assembled battery, The state estimation model uses the already calculated SOC, the already calculated constraint state value a ~ and the measured current value of the assembled battery as input information, and the SOC and constraint state value a of the assembled battery ~ as output information, The constraint state value a ~ is a value that depends on the non-expanded length a of the active material included in the assembled battery, the spring constant k of the member arranged adjacent to the assembled battery in the constraint direction of the assembled battery, and the spring constant k of the active material 1 and the spring constant k of the detection spring arranged adjacent to the assembled battery in the constraint direction s is a value that depends on

[0014] An estimation program for estimating the SOC (State Of Charge) of a battery pack formed by restraining a plurality of secondary batteries according to the present disclosure causes a computer to acquire battery information of the battery pack, and calculate the SOC, which is an estimated value of the battery pack, using the acquired battery information and a state estimation model of the battery pack, and execute, The battery information includes the SOC of the battery pack already calculated and a constraint state value a that depends on the constraint state of the battery pack ~ and the measured current value of the battery pack, The state estimation model uses the already calculated SOC, the already calculated constraint state value a ~ and the measured current value of the battery pack as input information, and the SOC and the constraint state value a of the battery pack ~ as output information, The constraint state value a ~ is a value that depends on the length a of the active material in the non-expanded state included in the battery pack, the spring constant k of the member disposed adjacent to the battery pack in the constraint direction of the battery pack and the active material 1 and the spring constant k of the constraint member that constrains the battery pack from the constraint direction. 2 is a value that depends on

[0015] An estimation program for estimating the SOC (State Of Charge) of a battery pack formed by restraining a plurality of secondary batteries according to the present disclosure causes a computer to acquire battery information of the battery pack, and calculate the SOC, which is an estimated value of the battery pack, using the acquired battery information and a state estimation model of the battery pack, and execute, The battery information includes the SOC of the battery pack already calculated and a constraint state value a that depends on the constraint state of the battery pack ~ and the measured current value of the battery pack, The state estimation model uses the already calculated SOC, the already calculated constraint state value a ~ and the measured current value of the battery pack as input information, and the SOC and the constraint state value a of the battery pack ~ as output information, The constraint state value a ~is the length a of the active material in the assembled battery in an unexpanded state, the spring constant k of the active material, and a member arranged adjacent to the assembled battery in the restraining direction of the assembled battery 1 and the spring constant k of the detection spring arranged adjacent to the assembled battery in the restraining direction s is a value that depends on these factors.

Advantages of the Invention

[0016] According to the present disclosure, it is possible to provide an estimation device, an estimation program, and an estimation method capable of improving the estimation accuracy of the SOC of a restrained assembled battery.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Modes for Carrying Out the Invention

[0018] <The First Embodiment> Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of an estimation device 10 according to the present disclosure. The estimation device 10 is a device that estimates the SOC of a secondary battery installed in a vehicle. As a specific example of the estimation device 10, for example, an ECU (Electronic Control Unit) installed in a vehicle can be mentioned.

[0019] The estimation device 10 includes a communication interface (I / F) 11, a storage device 12, and an arithmetic device 13. The communication I / F 11 is an interface that transmits and receives signals between the estimation device 10 and a secondary battery and other devices installed in the vehicle.

[0020] The storage device 12 is a storage device that stores an estimation program executed by the arithmetic device 13 and various information processed by the arithmetic device 13.

[0021] The arithmetic device 13 is an arithmetic device such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). The arithmetic device 13 executes the estimation method defined by the estimation program by executing the estimation program stored in the storage device 12. The estimation program includes a battery information acquisition unit 130, an estimated value calculation unit 131, and an estimated value correction unit 132. Note that an integrated circuit such as an FPGA (Field-Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit) may execute these program modules. Integrated circuits such as a CPU, an MPU, an FPGA, and an ASIC correspond to a computer.

[0022] The battery information acquisition unit 130 is a program module that acquires battery information of the battery pack. The battery information includes the SOC of the battery pack already calculated by the estimated value calculation unit 131, and a constraint state value a that depends on the constraint state of the battery pack already calculated by the estimated value calculation unit 131 ~, including the measured current value of the battery pack, the measured voltage value of the battery pack, and the measured strain amount of the battery pack. The battery information acquisition unit 130 can acquire the SOC and the constraint state value a of the battery pack calculated by the estimated value calculation unit 131 from the storage device 12 in which they are stored. The battery information acquisition unit 130 acquires the measured current value from a current sensor that detects the current of the secondary battery. Also, the battery information acquisition unit 130 acquires the measured voltage value from a voltage sensor that detects the voltage of the secondary battery. Further, the battery information acquisition unit 130 acquires the measured strain amount from a strain sensor that detects the strain amount in the constraint direction of the battery pack. ~ It can be obtained from the storage device 12 where these are stored. The battery information acquisition unit 130 acquires the measured current value from a current sensor that detects the current of the secondary battery. Also, the battery information acquisition unit 130 acquires the measured voltage value from a voltage sensor that detects the voltage of the secondary battery. Further, the battery information acquisition unit 130 acquires the measured strain amount from a strain sensor that detects the strain amount in the constraint direction of the battery pack.

[0023] The estimated value calculation unit 131 is a program module that calculates the SOC estimated value and the constraint state value a of the constrained battery pack. ~ The estimated value calculation unit 131 stores the calculated SOC and the constraint state value a of the battery pack in the storage device 12. Details of the processing executed by the estimated value calculation unit 131 will be described later. ~ Details of the processing executed by the estimated value calculation unit 131 will be described later.

[0024] The estimated value correction unit 132 is a program that corrects the errors of the estimated value and the estimated error covariance matrix calculated by the estimated value calculation unit 131. Details of the processing executed by the estimated value correction unit 132 will be described later.

[0025] FIG. 2 is a perspective view showing an example of a battery pack whose SOC is estimated by the estimation device 10. As shown in FIG. 2, the battery pack is formed by arranging a plurality of secondary batteries 1 in the thickness direction. Between each secondary battery 1, a spacer 2 is arranged as shown in FIG. 2. The battery pack is subjected to a restraining force in the thickness direction by a restraining member (not shown) such as a restraining bar. Therefore, in the present embodiment, the thickness direction of the secondary battery 1 corresponds to the constraint direction of the battery pack. Note that an electrode body such as a wound electrode body or a non-wound electrode body is housed inside the secondary battery 1. The electrode body is formed by laminating an electrode sheet and a separator.

[0026] As shown in Fig. 3, the secondary battery 1 can be modeled as a system including two springs arranged in parallel. In this embodiment, it is assumed that the distance between a pair of restraining plates restrained by a restraining member increases due to the expansion of the active material. In this model, the spacer, the active material, and the restraining member are regarded as elastic bodies. Further, the active material is regarded as an actuator whose dimension in the restraining direction increases due to its expansion. The amount of strain Δx shown in Fig. 3 is the amount of strain corresponding to the expansion displacement amount of the active material included in the secondary battery 1. The amount of strain Δx 1 is the amount of strain corresponding to the elastic displacement amounts of the spacer and the active material. The amount of strain Δx 2 is the amount of strain corresponding to the elastic displacement amount of the restraining member.

[0027] The amount of strain Δx (mm) can be expressed as in Equation (1).

Equation

[0028] Fig. 8 is a diagram showing an example of the relationship between SOC and the expansion rate g(SOC) of the active material. The expansion rate of the active material can be calculated by the X-ray diffraction method. For example, when the expansion rate g(SOC) of the active material when SOC is 0.8 (80%) is 1.11, the expansion characteristic value g of the active material used in the battery pack is approximately 1.39. In this way, the active material used in the battery pack is charged at various SOCs, and its expansion rate g(SOC) is measured. Then, based on SOC and the measured expansion rate g(SOC), the expansion characteristic value g of the active material can be calculated. The representative value of the expansion characteristic value g thus obtained, for example, the median value or the average value, can be adopted as the expansion characteristic value g shown in Equation (1).

[0029] The sum of the amount of deviation Δx and the amount of strain Δx corresponding to the elastic displacement amounts of the spacer and the active material 1 (mm) is equal to the amount of strain (mm) of the restraint member. Therefore, the amount of strain Δx 1 can be expressed as in Equation 2. [Number] Here, Δx 2 is the amount of strain of the restraint member. The expansion characteristic value g can be calculated by measuring the expansion rate and SOC of the active material of the prototype of the secondary battery 1.

[0030] When the spacer and the restraint member are regarded as elastic members, the relationship of Equation 3 can be derived from the balance between the compression force of the spacer and the elongation force of the restraint member when the active material expands. [Number] Here, k 1 is the spring constant (N / mm) of the spacer and the active material. k 2 is the spring constant (N / mm) of the restraint member.

[0031] Substitute the amount of strain Δx of Equation 1 into Equation 2, and then substitute the obtained amount of strain Δx 1 into Equation 3, thereby obtaining Equation 4. Equation 4 represents the SOC of the constrained assembled battery and the mathematical model for deriving a. [Number]

[0032] The estimated value calculation unit 131 is a program module that calculates the SOC estimated value of the constrained assembled battery. Specifically, the estimated value calculation unit 131 calculates the SOC of the constrained assembled battery and the constraint state value a defined by Equation 5 ~Estimate both of them. For this estimation, general estimation methods, such as the Extended Kalman Filter (EKF) or the Unscented Kalman Filter (UKF), etc., can be used.

[0033] In this embodiment, an extended model is adopted in which the measured current value is the input u[k] and the voltage and strain amount are the output y[k]. As shown in FIG. 4, this extended model includes a state estimation model f and an output estimation model h.

[0034] The state estimation model f is a mathematical model that estimates the vector x[k + 1] at the next time point k + 1 from the vector x[k] at a certain time point k. The vector x is a state variable group including the SOC or a variable corresponding to the SOC, and the constraint state value a defined by Equation 5 ~ and is a state vector. As the state estimation model f, a known equivalent circuit model, an electrochemical model (such as the Newman model), etc. can be adopted.

Equation

[0035] The output estimation model h is a mathematical model that estimates the output y[k] from the vector x[k]. The output estimation model h can be configured by adding Equation 6 obtained by transforming Equation 4 to a known mathematical model that outputs only the voltage as an estimated value. Specific examples of known mathematical models that output only the voltage as an estimated value include the equivalent circuit model disclosed in Japanese Patent No. 6555773. Specifically, the output estimation model can be configured by adding the following Equation 6 to the right side of the observation equation of Equation 10 in Japanese Patent No. 6555773. This output estimation model h can output not only the voltage but also the strain amount Δx of the restraint member 2 can be output.

Number

[0036] Next, a method for the estimation device 10 to estimate both the SOC and the restraint state value a ~ using an extended Kalman filter based on the above extended model is shown. The extended Kalman filter is divided into a state estimation process and a correction process.

[0037] FIG. 5 is a diagram showing an example of the process executed by the estimation device 10. The estimation device 10 repeatedly executes the process shown in FIG. 5. In step S1, the battery information acquisition unit 130 of the estimation device 10 acquires battery information. In the present embodiment, the battery information includes the measured current value, the measured strain amount Δx 2 , the SOC and the restraint state value a calculated and corrected in the previous process ~ .

[0038] In step S2, the estimated value calculation unit 131 of the estimation device 10 executes the process of FIG. 6. In step S3, the estimated value correction unit 132 of the estimation device 10 executes the process of FIG. 7.

[0039] FIG. 6 shows the SOC and the restraint state value a of the assembled battery ~It is a diagram showing an example of state estimation processing for estimating. In step S10, the estimated value calculation unit 131 linearizes the state estimation model f using the state vector x based on Equation 7.

Number

[0040] In step S11, the estimated value calculation unit 131 estimates the SOC and the constraint state value a ~ using the state estimation model based on Equation 8.

Number

[0041] In this way, the estimated value calculation unit 131 uses the SOC and the constraint state value a ~ of the assembled battery that have already been calculated and corrected in the previous process and the measured current value of the assembled battery as input information, and the SOC and the constraint state value a ~Using a state estimation model with output information, the SOC and the constraint state value a of the assembled battery ~ can be calculated.

[0042] In step S12, the estimated value calculation unit 131 derives the estimation error covariance matrix P - [k] based on Equation 9.

Equation

[0043] Figure 7 is a diagram showing an example of the correction process. The correction process is to correct the SOC and the constraint state value a, which are the estimated values calculated using the state estimation model in step S11 of Figure 6 ~ using the observation error y[k] - y ^ [k], and to determine the estimated value.

[0044] In step S20, the estimated value calculation unit 131 can estimate the voltage and / or the amount of strain using the output estimation model h based on Equation 10. Therefore, the estimated value calculation unit 131 also functions as an estimated strain amount calculation unit.

Equation

[0045] In step S21, the estimated value calculation unit 131 linearizes the output estimation model h using the state vector x based on Equation 11.

Equation

[0046] In step S22, the estimated value calculation unit 131 calculates the Kalman gain based on Equation 12.

Equation

[0047] In step S23, as shown in FIG. 8, the estimated value correction unit 132 corrects the SOC and the constraint state value a of the battery pack calculated in step S11 of FIG. 6 based on Equation 13. ~

Equation

[0048] The estimated value correction unit 132 adds the SOC and the constraint state value a calculated by the estimated value calculation unit 131 ~ to a value (g[k](y[k] - y ^- [k])) that depends on the difference between the estimated strain amount and the measured strain amount, thereby correcting the SOC and the constraint state value a calculated by the estimated value calculation unit 131 ~ The SOC and the constraint state value a of the battery pack corrected in this way ~ are used in subsequent state estimation processing

[0049] In other embodiments, the estimated value correction unit 132 may correct the SOC and the constraint state value a calculated by the estimated value calculation unit 131 using a value (g[k](y[k] - y ^- [k])) that depends on the difference between the estimated voltage value and the measured voltage value ~

[0050] In step S24, the estimated value correction unit 132 corrects the estimated error covariance matrix P - [k] based on Equation 14 [Equation] Here, P[k] represents the estimated error covariance matrix whose error has been corrected by the correction. g[k] represents the Kalman gain calculated in step S22. c[k] represents the output estimation model h linearized in step S21. P[k] obtained in step S24 is used as P[k - 1] in Equation (9) of step S12 in subsequent processing

[0051] ​In the above-described embodiment, the battery information acquisition unit 130 acquires battery information of the assembled battery. The estimated value calculation unit 131 calculates the SOC, which is an estimated value of the assembled battery, using the battery information acquired by the battery information acquisition unit 130 and the state estimation model of the assembled battery. The battery information includes the SOC of the assembled battery already calculated and the constraint state value a that depends on the constraint state of the assembled battery. ~ and the measured current value of the assembled battery. The state estimation model uses the already calculated SOC, the already calculated constraint state value a ~ and the measured current value of the assembled battery as input information, and outputs the SOC and the constraint state value a ~ of the assembled battery. The constraint state value a ~ is a value that depends on the length a of the non-expanded state of the active material included in the assembled battery, the spring constant k 1 of the member arranged adjacent to the assembled battery in the constraint direction of the assembled battery and the active material, and the spring constant k 2 of the constraint member that constrains the assembled battery from the constraint direction.

[0052] By adopting this configuration, it is possible to calculate the SOC in which the constraint state value a ~ that depends on the already calculated constraint state of the assembled battery is reflected. Therefore, since the SOC of the assembled battery can be calculated in consideration of the constraint state of the assembled battery by the constraint member, the estimation accuracy of the SOC can be improved. In addition, the SOC of the assembled battery can be estimated without acquiring measurement data for deriving the correlation between the volume change and temperature of the secondary battery 1.

[0053] Furthermore, the estimated value calculation unit 131 calculates the constraint state value a ~ , which is an estimated value of the secondary battery 1, using the state estimation model. The estimation device 10 further includes an estimated value correction unit 132 that corrects the SOC and the constraint state value a ~ calculated by the estimated value calculation unit 131. The estimated value calculation unit 131 inputs the SOC and the constraint state value a ~ corrected by the estimated value correction unit 132 into the state estimation model, thereby calculating the SOC of the assembled battery.

[0054] By adopting this configuration, the corrected SOC and constraint state value a~ Since the SOC of the secondary battery 1 is calculated using this, the estimation accuracy of the SOC can be improved.

[0055] <Second Embodiment> The battery pack according to the second embodiment is a battery pack in which a plurality of secondary batteries are constrained in a fixed size, and has a detection spring between the secondary battery and the constraining member. Hereinafter, the second embodiment will be described centering on the differences from the first embodiment.

[0056] In the second embodiment, as shown in FIG. 10, the secondary battery 1 can be modeled as a system including two springs arranged in series. In this model, a spring-type displacement sensor is arranged outside the secondary battery 1 in the thickness direction. In this model, the detection spring including the spacer, the active material, and the spring-type displacement sensor is regarded as an elastic body. Also, the length between a pair of constraining plates constrained by the constraining member is made constant. Since the length between the pair of constraining plates is constant, the amount of strain Δx corresponding to the expansion displacement amount of the active material, and the amount of strain Δx 1 and the displacement amount Δx of the detection spring s The relationship of can be defined as in Equation 15. The displacement amount Δx of the detection spring s can be obtained by the battery information acquisition unit 130 of the estimation device 10 from the spring-type displacement sensor.

Equation

[0057] Also, Equation 16 can be derived from the balance of forces between the spacer, which is an elastic material, and the detection spring of the displacement sensor.

Equation

[0058] When Δx obtained by transforming Equation 16 1 is substituted into Equation 15, Equation 17 is obtained. [Mathematics]

[0059] Substituting Equation 1 into Δx in Equation 17 and simplifying gives Equation 18. [Mathematics] Equation 18 corresponds to Equation 6 used in the first embodiment. The output estimation model h according to the second embodiment can be configured by adding Equation 18 to a known mathematical model that outputs only voltage as an estimated value. This output estimation model h can output not only the voltage but also the displacement amount Δx of the detection spring s .

[0060] In the second embodiment, the estimated value correction unit 132 corrects the SOC and the constraint state value a of the battery pack calculated in step S11 of FIG. 6 based on Equation 13 ~ . y[k] in Equation 13 represents the measured voltage of the battery pack and / or the measured displacement amount Δx of the detection spring s . y ^- [k] represents the estimated voltage value of the battery pack calculated by the output estimation model h and the estimated displacement amount Δx of the detection spring s .

[0061] The estimated value correction unit 132 adds the SOC and the constraint state value a calculated by the estimated value calculation unit 131 to a value (g[k](y[k] - y ~ [k])) that depends on the difference between the estimated displacement amount Δx of the detection spring s and the measured displacement amount Δx of the detection spring s to correct the SOC and the constraint state value a calculated by the estimated value calculation unit 131. The SOC and the constraint state value a of the battery pack corrected in this way ^- [k]) are used in subsequent state estimation processing. ~ ~

[0062] In the second embodiment, the constraint state value a ~can be defined as shown in Equation 19. In other words, the constraint state value a ~ is the product of the spring constant k 1 and the length a before expansion of the active material contained in the secondary battery 1, divided by the sum of the spring constant k 1 and the spring constant k of the detection spring arranged adjacent to the assembled battery in the constraint direction s and corresponds to a negative value obtained by dividing the product by the sum. [Number]

[0063] In the above example, when the program is loaded into a computer, it includes a set of instructions (or software code) for causing the computer to perform one or more functions described in the embodiments. The program may be stored in a non-transitory computer-readable medium or a tangible storage medium. By way of example and not limitation, the computer-readable medium or tangible storage medium includes random-access memory (RAM), read-only memory (ROM), flash memory, solid-state drive (SSD), or other memory technologies, CD-ROM, digital versatile disk (DVD), Blu-ray (registered trademark) disk, or other optical disk storage, magnetic cassette, magnetic tape, magnetic disk storage, or other magnetic storage devices. The program may be transmitted on a transitory computer-readable medium or a communication medium. By way of example and not limitation, the transitory computer-readable medium or communication medium includes electrical, optical, acoustic, or other forms of propagated signals.

[0064] The present disclosure is not limited to the above-described embodiments, and can be appropriately modified without departing from the spirit of the present disclosure. [Description of Reference Numerals]

[0065] 1 Secondary battery 2 Spacer 10 Estimation device 11 Communication I / F 12 Memory device 13 Arithmetic unit 130 Battery information acquisition unit 131 Estimated value calculation unit 132 Estimated value correction unit

Claims

1. An estimation device for estimating the State Of Charge (SOC) of a battery pack formed by constraining a plurality of secondary batteries, comprising: a battery information acquisition unit that acquires battery information of the battery pack; an estimated value calculation unit that calculates the SOC, which is an estimated value of the battery pack, using the battery information acquired by the battery information acquisition unit and a state estimation model of the battery pack; The battery information includes the SOC of the battery pack that has already been calculated and a constraint state value a that depends on the state of constraint of the battery pack, ～ and the measured current value of the battery pack, The state estimation model uses the already calculated SOC, the already calculated constraint state value a ～ and the measured current value of the battery pack as input information, and outputs the SOC and the constraint state value a ～ of the battery pack The constrained state value a ～ is a value that depends on the length a of the active material in the assembled battery in a non-expanded state, the spring constant k of the member disposed adjacent to the assembled battery in the constrained direction of the assembled battery, and the active material １ and the spring constant k of the constraining member that constrains the assembled battery from the constrained direction ２ and is a value that depends on an estimation device.

2. The constrained state value a ～ is the product of the length a and the spring constant k １ and the spring constant k ２ divided by the sum of the spring constant k １ and the spring constant k ２ The estimation device according to claim 1 corresponding to the value obtained by the division.

3. An estimation device for estimating the State Of Charge (SOC) of a battery pack formed by constraining a plurality of secondary batteries, comprising: a battery information acquisition unit that acquires battery information of the battery pack; an estimated value calculation unit that calculates the SOC, which is an estimated value of the battery pack, using the battery information acquired by the battery information acquisition unit and a state estimation model of the battery pack; The battery information includes the SOC of the assembled battery already calculated and a constraint state value a that depends on the state of constraint of the assembled battery ～ and the measured current value of the assembled battery, The state estimation model uses the already calculated SOC, the already calculated constraint state value a ～ and the measured current value of the battery pack as input information, and outputs the SOC and the constraint state value a ～ of the battery pack The constrained state value a ～ is a value that depends on the non-expanded length a of the active material included in the assembled battery, the spring constant k of the member arranged adjacent to the assembled battery in the constraint direction of the assembled battery, and the active material １ and the spring constant k of the detection spring arranged adjacent to the assembled battery in the constraint direction ｓ and is a value that depends on the spring constant k of the detection spring arranged adjacent to the assembled battery in the constraint direction an estimation device.

4. The constrained state value a ～ is the product of the spring constant k １ and the length a, divided by the sum of the spring constant k １ and the spring constant k ｓ and corresponds to a negative value, and the estimation device according to claim 3

5. The estimated value calculation unit further calculates a constrained state value a, which is an estimated value of the secondary battery, using the state estimation model. ～ and The estimation device further includes an estimated value correction unit that corrects the SOC and the constraint state value a calculated by the estimated value calculation unit ～ and The estimated value calculation unit inputs the SOC and the constraint state value a corrected by the estimated value correction unit into the state estimation model to calculate the SOC of the assembled battery. The estimation device according to any one of claims 1 to 4. ～ ​

6. The estimation device according to any one of claims 1 to 4, wherein the state estimation model is an equivalent circuit model or an electrochemical model.

7. An estimation method for estimating the State Of Charge (SOC) of a battery pack formed by constraining a plurality of secondary batteries, the method comprising the steps of: a computer acquiring battery information of the battery pack; calculating the SOC, which is an estimated value of the battery pack, using the acquired battery information and a state estimation model of the battery pack; The battery information includes the SOC of the battery pack that has already been calculated and a constraint state value a that depends on the state of constraint of the battery pack ～ and the measured current value of the battery pack, The state estimation model uses the already calculated SOC, the already calculated constraint state value a ～ and the measured current value of the battery pack as input information, and outputs the SOC and the constraint state value a ～ of the battery pack The constrained state value a ～ is a value that depends on the length a of the active material in the unexpanded state included in the assembled battery, the spring constant k of the member disposed adjacent to the assembled battery in the constraint direction of the assembled battery, and the active material １ and the spring constant k of the constraint member that constrains the assembled battery from the constraint direction ２ is a value that depends on an estimation method.

8. An estimation method for estimating the State Of Charge (SOC) of a battery pack formed by constraining a plurality of secondary batteries, the method comprising the steps of: a computer acquiring battery information of the battery pack; calculating the SOC, which is an estimated value of the battery pack, using the acquired battery information and a state estimation model of the battery pack; The battery information includes the SOC of the assembled battery that has already been calculated and a constraint state value a that depends on the state of constraint of the assembled battery ～ and the measured current value of the assembled battery, The state estimation model uses the already calculated SOC, the already calculated constraint state value a ～ and the measured current value of the battery pack as input information, and outputs the SOC and the constraint state value a ～ of the battery pack as output information. The constrained state value a ～ is a value that depends on the length a of the active material in the non-expanded state included in the assembled battery, the spring constant k of the member arranged adjacent to the assembled battery in the constrained direction of the assembled battery, and the active material １ and the spring constant k of the detection spring arranged adjacent to the assembled battery in the constrained direction ｓ and is a value that depends on an estimation method.

9. An estimation program for estimating the State Of Charge (SOC) of a battery pack formed by constraining a plurality of secondary batteries, the program causing a computer to acquire battery information of the battery pack; calculate the SOC, which is an estimated value of the battery pack, using the acquired battery information and a state estimation model of the battery pack, and execute; The battery information includes the SOC of the assembled battery already calculated and a constraint state value a that depends on the state of constraint of the assembled battery ～ and the measured current value of the assembled battery, The state estimation model uses the already calculated SOC, the already calculated constraint state value a ～ and the measured current value of the battery pack as input information, and outputs the SOC and the constraint state value a ～ of the battery pack as output information. The constrained state value a ～ is a value that depends on the length a of the active material in the unexpanded state included in the assembled battery, the spring constant k of the member disposed adjacent to the assembled battery in the constraint direction of the assembled battery and the active material １ and the spring constant k of the constraint member that constrains the assembled battery from the constraint direction ２ and is a value that depends on an estimation program.

10. An estimation program for estimating the State Of Charge (SOC) of a battery pack formed by constraining a plurality of secondary batteries, the program causing a computer to acquire battery information of the battery pack; Execute including a step of calculating an SOC, which is an estimated value of the assembled battery, using the obtained battery information and the state estimation model of the assembled battery. The battery information includes the SOC of the battery pack already calculated and a constraint state value a that depends on the state of constraint of the battery pack ～ and the measured current value of the battery pack, The state estimation model uses the already calculated SOC, the already calculated constraint state value a ～ and the measured current value of the battery pack as input information, and outputs the SOC and the constraint state value a ～ of the battery pack The constrained state value a ～ is a value that depends on the length a of the active material in an unexpanded state included in the assembled battery, the spring constant k of the member disposed adjacent to the assembled battery in the constrained direction of the assembled battery and the active material １ and the spring constant k of the detection spring disposed adjacent to the assembled battery in the constrained direction ｓ and is a value that depends on Estimation program.

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