Estimation device, estimation method, and estimation program

Abstract

To provide an estimation device, an estimation method, and an estimation program with which it is possible to improve the accuracy of estimating the internal pressure of secondary battery.SOLUTION: An estimation device 10 includes: a first airflow calculation unit 132 that calculates a first airflow generated by an air blower, on the basis of one of the revolution speed of the rotary part of the air blower that cools a secondary battery, the current supplied to the air blower, and the voltage supplied to the air blower; an internal pressure estimation value calculation unit 131 that calculates an internal pressure estimation value that is the estimated value of internal pressure of the secondary battery on the basis of information pertaining to the secondary battery; a second airflow calculation unit 133 that calculates a second airflow that is the airflow in a container that accommodates one or more secondary batteries, on the basis of the internal pressure estimation value and the revolution speed; a correction value calculation unit 136 that calculates a correction value for correcting the internal pressure estimation value, on the basis of a difference between the first and the second airflows; and an internal pressure estimation value correction unit 137 that corrects the internal pressure estimation value using the correction value.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] This disclosure relates to an estimation device, estimation method, and estimation program for estimating the internal pressure of a secondary battery. [Background technology]

[0002] Currently, electric vehicles, hybrid vehicles, plug-in hybrid vehicles, and other vehicles that use electricity as a driving force utilize rechargeable batteries such as nickel-metal hydride batteries and lithium-ion batteries. Various technologies have been proposed to estimate the internal pressure of such rechargeable batteries.

[0003] The internal pressure estimation system disclosed in Patent Document 1 calculates the oxygen pressure from the amount of oxygen gas generated at the positive electrode of the nickel-metal hydride battery and the amount of oxygen gas absorbed by the reaction between hydrogen and oxygen gas incorporated into the hydrogen storage alloy, which is the negative electrode. The internal pressure of the nickel-metal hydride battery is then calculated using the calculated oxygen pressure and the hydrogen equilibrium pressure of the hydrogen storage alloy. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2017-91790 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] Normally, secondary batteries expand and contract due to changes in their internal pressure. However, the internal pressure estimation system disclosed in Patent Document 1 does not take such changes in the internal pressure of secondary batteries into account, so there was room to improve the accuracy of estimating the internal pressure of secondary batteries.

[0006] This disclosure aims to provide an estimation device, estimation method, and estimation program that can improve the accuracy of estimating the internal pressure of a secondary battery in order to solve the problems described above. [Means for solving the problem]

[0007] An estimation device for estimating the internal pressure of a secondary battery according to one embodiment is: A first airflow calculation unit calculates a first airflow generated by a blower based on one of the following: the rotational speed of the rotating part of the blower that cools the secondary battery, the current supplied to the blower, or the voltage supplied to the blower. An internal pressure estimation unit calculates an internal pressure estimate, which is an estimated value of the internal pressure of a secondary battery, based on information about the secondary battery. A second airflow calculation unit calculates a second airflow rate, which is the airflow rate inside a container housing one or more secondary batteries, based on the internal pressure estimate calculated by the internal pressure estimation unit and the rotational speed. A correction value calculation unit calculates a correction value for correcting the internal pressure estimate based on the difference between the first airflow rate calculated by the first airflow rate calculation unit and the second airflow rate calculated by the second airflow rate calculation unit. The system includes an internal pressure estimate correction unit that corrects the internal pressure estimate calculated by the internal pressure estimate calculation unit using the correction value calculated by the correction value calculation unit.

[0008] The second airflow calculation unit can calculate the second airflow by multiplying the airflow change rate, which indicates the change in the second airflow due to the change in internal pressure, by the third airflow, which is the airflow inside the container in an unexpanded state calculated based on the rotation speed.

[0009] Furthermore, the estimation device may further include an airflow rate change calculation unit that calculates the airflow rate change corresponding to the internal pressure estimate calculated by the internal pressure estimate calculation unit, based on a known correspondence between internal pressure and airflow rate change.

[0010] Furthermore, the estimation device may further include a third airflow calculation unit that calculates a third airflow corresponding to a rotational speed based on a known correspondence between rotational speed and a third airflow.

[0011] The correction value calculation unit can calculate a correction value by multiplying a coefficient that has a positive correlation with the internal pressure by the value obtained by subtracting the second airflow rate from the first airflow rate.

[0012] The internal pressure estimated value correction unit can correct the internal pressure estimated value by adding a correction value to the internal pressure estimated value.

[0013] An estimation method for estimating the internal pressure of a secondary battery according to an embodiment is such that a computer calculates a first air volume generated by a blower based on any one of the rotation speed of the rotating part of the blower that cools the secondary battery, the current supplied to the blower, and the voltage supplied to the blower, calculates an internal pressure estimated value, which is an estimated value of the internal pressure of the secondary battery, based on information regarding the secondary battery, calculates a second air volume, which is the air volume in a container that houses one or more secondary batteries, based on the calculated internal pressure estimated value and the rotation speed, calculates a correction value for correcting the internal pressure estimated value based on the difference between the calculated first air volume and the second air volume, corrects the calculated internal pressure estimated value using the calculated correction value.

[0014] An estimation program for estimating the internal pressure of a secondary battery according to an embodiment causes a computer to calculate a first air volume generated by a blower based on any one of the rotation speed of the rotating part of the blower that cools the secondary battery, the current supplied to the blower, and the voltage supplied to the blower, calculate an internal pressure estimated value, which is an estimated value of the internal pressure of the secondary battery, based on information regarding the secondary battery, calculate a second air volume, which is the air volume in a container that houses one or more secondary batteries, based on the calculated internal pressure estimated value and the rotation speed, calculate a correction value for correcting the internal pressure estimated value based on the difference between the calculated first air volume and the second air volume, correct the calculated internal pressure estimated value using the calculated correction value.

Advantages of the Invention

[0015] According to the present disclosure, it is possible to provide an estimation device, an estimation method, and an estimation program capable of improving the estimation accuracy of the internal pressure of a secondary battery.

Brief Description of the Drawings

[0016] [Figure 1] This figure shows an example of a secondary battery pack. [Figure 2] This is a block diagram showing an example of the configuration of an estimation device. [Figure 3] This diagram shows the relationship between the rotation speed of the blower's rotating part and the third airflow rate. [Figure 4] This figure shows the relationship between the internal pressure of a secondary battery and the rate of change in airflow. [Figure 5] This figure shows the relationship between the internal pressure of a secondary battery and the coefficient K. [Figure 6] This flowchart shows an example of the process performed by the estimation device. [Figure 7] This flowchart shows an example of the process for calculating the second airflow rate. [Modes for carrying out the invention]

[0017] Various embodiments will be described below with reference to the drawings. Figure 1 shows an example of a secondary battery pack 1. The secondary battery pack 1 comprises a container in which one or more secondary batteries are arranged and housed. A blower 2 is positioned adjacent to the secondary battery pack 1 to generate cooling air for cooling the secondary batteries inside the container. A flow path for the cooling air that cools the secondary batteries is formed inside the container. This flow path can be reduced and expanded by the expansion and contraction of the secondary batteries inside the container.

[0018] Figure 2 is a block diagram showing the configuration of an estimation device 10 according to one embodiment. The estimation device 10 is a device for estimating the internal pressure of a secondary battery. A specific example of the estimation device 10 is an ECU (Electronic Control Unit) installed in a vehicle.

[0019] The estimation device 10 comprises a communication interface (I / F) 11, a storage device 12, and an arithmetic unit 13. The communication I / F 11 is an interface for sending and receiving signals between the estimation device 10 and the secondary battery and other devices installed in the vehicle.

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

[0021] The arithmetic unit 13 is an arithmetic unit such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). The arithmetic unit 13 executes an estimation method for estimating the internal pressure of a secondary battery by executing an estimation program stored in the memory device 12. The estimation program includes an acquisition unit 130, an internal pressure estimation value calculation unit 131, a first airflow rate calculation unit 132, a second airflow rate calculation unit 133, a third airflow rate calculation unit 134, an airflow rate change rate calculation unit 135, a correction value calculation unit 136, and an internal pressure estimation value correction unit 137. Note that integrated circuits such as FPGAs (Field-Programmable Gate Arrays) or ASICs (Application Specific Integrated Circuits) may execute these programs.

[0022] The acquisition unit 130 is a program that acquires information about the blower 2 and information about the secondary battery. The information about the blower 2 includes the rotation speed of the rotating part (e.g., blower or fan) of the blower 2 and the current supplied to the blower 2. The acquisition unit 130 can acquire the rotation speed from a sensor that detects the rotation speed of the rotating part of the blower 2 via the communication I / F 11. The acquisition unit 130 can also acquire the value of the current supplied to the blower 2 from a current sensor (not shown) that detects the current supplied to the blower 2. Furthermore, the acquisition unit 130 can acquire the value of the voltage supplied to the blower 2 from a voltage sensor (not shown) that detects the voltage supplied to the blower 2.

[0023] Information regarding the secondary battery includes the current, voltage, and temperature of the secondary battery. The acquisition unit 130 can acquire the current of the secondary battery from a current sensor (not shown) that detects the current of the secondary battery. The acquisition unit 130 can also acquire the voltage of the secondary battery from a current sensor (not shown) that detects the voltage of the secondary battery. Furthermore, the acquisition unit 130 can acquire the temperature of the secondary battery from a temperature sensor (not shown) that detects the temperature inside the secondary battery pack 1.

[0024] The internal pressure estimated value calculation unit 131 is a program that calculates an internal pressure estimated value, which is an estimated value of the internal pressure of the secondary battery, based on information regarding the secondary battery. For example, when estimating the internal pressure of a nickel-metal hydride battery, the internal pressure estimated value calculation unit 131 calculates an estimated oxygen pressure p Ok in the secondary battery pack 1 based on the following mathematical formula 1. Note that the internal pressure estimated value calculation unit 131 can estimate the internal pressure of a non-aqueous electrolyte secondary battery such as a lithium-ion battery, in addition to an alkaline secondary battery such as a nickel-metal hydride battery.

Equation

[0025] Next, the internal pressure estimated value calculation unit 131 can calculate the internal pressure estimated value p k based on the following mathematical formula 2.

Equation

[0026] The first airflow calculation unit 132 is a program that calculates a first airflow generated by the blower 2 based on one of the following: the rotational speed of the rotating part of the blower 2 that cools the secondary battery, the current supplied to the blower, or the voltage supplied to the blower. More specifically, the first airflow calculation unit 132 acquires the rotational speed of the rotating part of the blower 2. Then, based on a known correspondence between the rotational speed of the rotating part of the blower 2 and the first airflow, the first airflow calculation unit 132 calculates the first airflow corresponding to the acquired rotational speed. The correspondence between rotational speed and the first airflow can be obtained by measuring the first airflow output by the blower 2 at various rotational speeds. Furthermore, the correspondence between rotational speed and the first airflow can be expressed by a mathematical formula or by a map such as a graph.

[0027] Furthermore, the first airflow calculation unit 132 can also calculate a first airflow based on the current or voltage supplied to the blower 2. Specifically, the first airflow calculation unit 132 acquires the value of the current or voltage supplied to the blower 2. Then, based on a known correspondence between the value of the current or voltage supplied to the blower 2 and the first airflow, the first airflow calculation unit 132 calculates a first airflow corresponding to the acquired current or voltage value. The correspondence between the current or voltage value and the first airflow can be obtained by measuring the first airflow of the blower 2 supplied with various magnitudes of current or voltage.

[0028] The second airflow calculation unit 133 is a program that calculates a second airflow, which is the airflow inside a container housing one or more secondary batteries, based on the internal pressure estimate calculated by the internal pressure estimate calculation unit 131 and the rotation speed of the rotating part of the blower 2. As shown in equation 3, the second airflow calculation unit 133 can calculate the second airflow by multiplying the airflow change rate, which indicates the change in the second airflow due to the change in the internal pressure of the secondary batteries, by the third airflow, which is the airflow inside the container when the secondary batteries are not expanding.

number

[0029] The third airflow calculation unit 134 is a program that calculates a third airflow based on the rotational speed of the rotating part of the blower 2. As shown in Equation 4, the third airflow calculation unit 134 can calculate a third airflow corresponding to the rotational speed acquired by the acquisition unit 130, based on the known correspondence between the rotational speed of the rotating part of the blower 2 and the third airflow.

number

[0030] The airflow rate change calculation unit 135 is a program that calculates the airflow rate change, which represents the second change in airflow caused by the change in the internal pressure of the secondary battery. As shown in Equation 5, the airflow rate change calculation unit 135 can calculate the airflow rate change corresponding to the internal pressure estimate calculated by the internal pressure estimate calculation unit 131, based on the known correspondence between the internal pressure of the secondary battery and the airflow rate change.

number

[0031] The correction value calculation unit 136 is a program that calculates a correction value to correct the internal pressure estimate calculated by the internal pressure estimate calculation unit 131, based on the difference between the first airflow rate calculated by the first airflow rate calculation unit 132 and the second airflow rate calculated by the second airflow rate calculation unit 133. More specifically, as shown in equation 6, the correction value calculation unit 136 can calculate the correction value by multiplying a coefficient that has a positive correlation with the internal pressure of the secondary battery by the value obtained by subtracting the second airflow rate from the first airflow rate.

number

[0032] The internal pressure estimate correction unit 137 is a program that corrects the internal pressure estimate calculated by the internal pressure estimate calculation unit 131 using the correction value calculated by the correction value calculation unit 136. More specifically, as shown in Equation 7, the internal pressure estimate correction unit 137 can correct the internal pressure estimate by adding the correction value to the internal pressure estimate.

number

[0033] Figure 6 is a flowchart showing an example of the process performed by the estimation device 10. In step S1, the acquisition unit 130 acquires information about the blower 2. In step S2, the acquisition unit 130 acquires information about the secondary battery. In step S3, the first airflow calculation unit 132 calculates the first airflow Q means In step S4, the internal pressure estimation unit 131 calculates the internal pressure estimation value p. In step S5, the second airflow calculation unit 133 calculates the second airflow Q. est The correction value calculation unit 136 calculates the correction value Cor p The internal pressure estimation correction unit 137 calculates the correction value Cor calculated in step S6. p The internal pressure estimate p calculated in step S4 is corrected using this method.

[0034] Figure 7 shows the second airflow rate Q. est This flowchart shows an example of the process for calculating the airflow rate change rate. In step S11, the airflow rate change rate calculation unit 135 calculates the airflow rate change rate Cor Q The third airflow calculation unit 134 calculates the third airflow Q. In step S12, the third airflow calculation unit 134 calculates the third airflow Q. equ The second airflow calculation unit 133 calculates the airflow rate change Cor calculated in step S11. Q And the third airflow Q calculated in step S12 equ Using this, the second airflow Q est Calculate.

[0035] In the embodiment described above, the first airflow calculation unit 132 calculates a first airflow generated by the blower 2 based on one of the following: the rotational speed of the rotating part of the blower 2 that cools the secondary battery, the current supplied to the blower, or the voltage supplied to the blower. The internal pressure estimation value calculation unit 131 calculates an internal pressure estimate, which is an estimated value of the internal pressure of the secondary battery, based on information about the secondary battery. The second airflow calculation unit 133 calculates a second airflow, which is the airflow inside a container housing one or more secondary batteries, based on the internal pressure estimation value calculated by the internal pressure estimation value calculation unit 131 and the rotational speed of the blower 2. The correction value calculation unit 136 calculates a correction value to correct the internal pressure estimate, based on the difference between the first airflow calculated by the first airflow calculation unit 132 and the second airflow calculated by the second airflow calculation unit 133. The internal pressure estimate correction unit 137 corrects the internal pressure estimate calculated by the internal pressure estimate calculation unit using the correction value calculated by the correction value calculation unit 136.

[0036] The second airflow rate is the airflow rate within a container housing one or more secondary batteries, and changes due to the contraction and expansion of the cooling airflow path within the container. Such contraction and expansion of the cooling airflow path is caused by the expansion and contraction of the secondary batteries due to changes in their internal pressure. Therefore, by calculating a correction value based on the second airflow rate that reflects the effects of the contraction and expansion of the cooling airflow path, and correcting the internal pressure estimate using this correction value, it is possible to derive an internal pressure estimate that reflects such changes in the internal pressure of the secondary batteries. As a result, the accuracy of estimating the internal pressure of the secondary batteries can be improved. In particular, the technology of this disclosure can improve the accuracy of estimating the internal pressure of secondary batteries even when the internal pressure estimate is used recursively to estimate the internal pressure. By improving the accuracy of estimating the internal pressure of secondary batteries in this way, it is possible to predict in advance the opening of the sealing valve of the secondary battery due to an increase in the internal pressure of the secondary battery, and to prevent the sealing valve from opening.

[0037] The estimated program described above, when loaded into a computer, includes 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 disk (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 propagating signals of electrical, optical, acoustic or other forms. In addition to the ECU, a computer includes various devices such as a PC (Personal Computer), server, CPU, MPU, FPGA, ASIC, etc.

[0038] This disclosure is not limited to the embodiments described above, and may be modified as appropriate without departing from the spirit of this disclosure. [Explanation of symbols]

[0039] 1. Rechargeable battery pack 2. Blower 10 Estimation device 11 Communication I / F 12 Storage device 13 Arithmetic unit 130 Acquisition Department 131 Internal pressure estimation calculation unit 132 First airflow calculation unit 133 Second airflow calculation unit 134 Third airflow calculation unit 135 Airflow change rate calculation unit 136 Correction Value Calculation Unit 137 Internal pressure estimation correction unit

Claims

1. An estimation device for estimating the internal pressure of a secondary battery, A first airflow calculation unit calculates a first airflow generated by the blower based on the rotational speed of the blower's rotating part for cooling the secondary battery, the current supplied to the blower, or the voltage supplied to the blower. An internal pressure estimation unit calculates an internal pressure estimation value, which is an estimated value of the internal pressure of the secondary battery, based on the information relating to the secondary battery. A second airflow calculation unit calculates a second airflow, which is the airflow inside a container housing one or more secondary batteries, based on the internal pressure estimate calculated by the internal pressure estimate calculation unit and the rotation speed. A correction value calculation unit calculates a correction value for correcting the internal pressure estimate based on the difference between the first airflow calculated by the first airflow calculation unit and the second airflow calculated by the second airflow calculation unit. An internal pressure estimate correction unit corrects the internal pressure estimate calculated by the internal pressure estimate calculation unit using the correction value calculated by the correction value calculation unit. An estimation device, including one.

2. The estimation device according to claim 1, wherein the second airflow calculation unit calculates the second airflow by multiplying the airflow change rate, which indicates the change in the second airflow due to the change in internal pressure, by a third airflow, which is the airflow inside the container when the secondary battery is not expanding, calculated based on the rotation speed.

3. The estimation apparatus according to claim 2, further comprising an airflow rate change calculation unit that calculates the airflow rate change corresponding to the internal pressure estimate calculated by the internal pressure estimate calculation unit, based on a known correspondence between the internal pressure and the airflow rate change.

4. The estimation device according to claim 2, further comprising a third airflow calculation unit that calculates the third airflow corresponding to the rotational speed based on a known correspondence between the rotational speed and the third airflow.

5. The estimation device according to any one of claims 1 to 4, wherein the correction value calculation unit calculates the correction value by multiplying a coefficient having a positive correlation with the internal pressure by a value obtained by subtracting the second airflow from the first airflow.

6. The estimation device according to claim 5, wherein the internal pressure estimation value correction unit corrects the internal pressure estimation value by adding the correction value to the internal pressure estimation value.

7. A method for estimating the internal pressure of a secondary battery, wherein a computer... Based on the rotational speed of the rotating part of the blower that cools the secondary battery, the current supplied to the blower, and the voltage supplied to the blower, the first airflow generated by the blower is calculated. Based on the information regarding the secondary battery, an estimated internal pressure value, which is an estimated value of the internal pressure of the secondary battery, is calculated. Based on the calculated internal pressure estimate and the rotational speed, a second airflow rate is calculated, which is the airflow rate inside the container housing one or more secondary batteries. Based on the difference between the calculated first airflow rate and the second airflow rate, a correction value is calculated to correct the estimated internal pressure. The calculated internal pressure estimate is corrected using the calculated correction value. Estimation method.

8. An estimation program for estimating the internal pressure of a secondary battery, which provides a computer with the following information: Based on the rotational speed of the rotating part of the blower that cools the secondary battery, the current supplied to the blower, and the voltage supplied to the blower, the first airflow generated by the blower is calculated. Based on the information regarding the secondary battery, the internal pressure estimate, which is an estimated value of the internal pressure of the secondary battery, is calculated. Based on the calculated internal pressure estimate and the rotational speed, a second airflow rate, which is the airflow rate inside a container housing one or more secondary batteries, is calculated. Based on the difference between the calculated first airflow rate and the second airflow rate, a correction value is calculated to correct the estimated internal pressure. The calculated correction value is used to correct the calculated internal pressure estimate. Estimation program.

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