System

Abstract

To provide a technique to improve the accuracy of estimating the state of a battery installed in a mobile body.SOLUTION: The system that estimates the state of a battery used for driving a mobile body includes: a two-dimensional code that has characteristic information including temperature characteristic information in accordance with an individual sensor of at least one of a voltage sensor that measures voltage of the battery and a current sensor that measures current of the battery and is imprinted on the sensor; and a rewriting tool that acquires the characteristic information by reading the two-dimensional code to reflect the characteristic information in a storage unit for a control unit.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a system for estimating a battery state of a battery. [Background technology]

[0002] 2. Description of the Related Art Conventionally, a voltage sensor that is mounted on a moving object such as a vehicle and measures the voltage of a battery is known (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2022-096272 A Summary of the Invention [Problem to be solved by the invention]

[0004] The characteristics of sensors such as voltage sensors can change due to individual differences caused by manufacturing variations and the temperature of the environment in which the battery is used. The battery state is estimated based on the values ​​of the voltage sensor and current sensor, but the measurement accuracy of the sensor may decrease depending on the sensor characteristics. If the measurement accuracy of the voltage sensor and current sensor decreases, the estimation accuracy of the battery state also decreases. [Means for solving the problem]

[0005] The present disclosure can be realized in the following forms.

[0006] (1) According to a first aspect of the present disclosure, there is provided a system for estimating a battery state of a battery used to drive a moving object, the system including a two-dimensional code imprinted on the sensor having characteristic information including temperature characteristic information corresponding to an individual sensor of at least one of a voltage sensor for measuring a voltage of the battery and a current sensor for measuring a current of the battery, and a rewriting tool for acquiring the characteristic information by reading the two-dimensional code and reflecting the characteristic information in a storage unit of a control unit. According to this aspect, it is possible to obtain information on errors due to changes in the characteristics of each individual voltage sensor or current sensor mounted on the moving object, thereby improving the measurement accuracy of the sensors, and thereby improving the estimation accuracy of the battery state of the moving object. The present disclosure can be realized in various forms, and in addition to the forms described above, can be realized in the form of a computer program that realizes a method for estimating a battery state, a non-transitory recording medium on which the computer program is recorded, etc. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is an explanatory diagram showing the configuration of a system for estimating a battery state. [Diagram 2] FIG. 4 is an explanatory diagram showing an example of map information. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] A. First embodiment: 1 is an explanatory diagram showing the configuration of a system 400 for estimating the battery state of a battery. The system 400 includes a vehicle 1 as a moving object, a QR code reader 200, and a rewriting tool 300. The vehicle 1 is equipped with a battery pack 100 having a battery used to drive the vehicle 1. The vehicle 1 also includes a communication device (not shown).

[0009] The battery pack 100 includes a battery 110, a monitoring unit 120, and an electronic control unit (hereinafter, ECU; Electronic Control Unit) 130. The battery 110 has a plurality of secondary batteries 112. The secondary batteries 112 are, for example, lithium ion batteries. Note that the secondary batteries 112 are not limited to lithium ion batteries, and may be other batteries such as nickel-metal hydride batteries. Also, the battery 110 corresponds to the above-mentioned "battery."

[0010] The monitoring unit 120 includes various sensors for monitoring the battery 110. Specifically, the monitoring unit 120 includes a voltage sensor 122, a current sensor 125, and a temperature sensor 128. The voltage sensor 122 detects the voltage V of the secondary battery 112. B The current sensor 125 measures the current I B The temperature sensor 128 measures the temperature T B Each sensor outputs a signal indicating the detection result to the battery ECU 130. In this embodiment, a QR code (registered trademark) 123 as a two-dimensional code is marked on the voltage sensor 122, and a QR code 126 is marked on the current sensor 125. In the following description, when there is no particular distinction between the voltage sensor 122 and the current sensor 125, they will be simply referred to as "sensors," and when there is no particular distinction between the QR codes 123 and 126, they will be simply referred to as "QR codes." Note that the QR code does not need to be marked on both the voltage sensor 122 and the current sensor 125 as in this embodiment, and may be marked on at least one of the voltage sensor 122 and the current sensor 125.

[0011] The battery ECU 130 includes a processor 132 such as a CPU (Central Processing Unit), a memory 135 such as a ROM (Read Only Memory) and a RAM (Random Access Memory), and an input / output port (not shown) through which various signals are input and output. The memory 135 corresponds to a storage unit. The processor 132 monitors the battery 110 based on signals output from each sensor and a program PG1 and a map MP1 stored in the memory 135. More specifically, for example, the battery ECU 130 calculates the SOC (State Of Charge) and battery capacity of the battery 110. In the present disclosure, the SOC and battery capacity are collectively referred to as the "battery state". However, the "battery state" is not limited to the SOC and battery capacity.

[0012] QR code 123 imprinted on voltage sensor 122 and QR code 126 imprinted on current sensor 125 have characteristic information including temperature characteristic information according to the individual sensor. Here, "individual" means each sensor that can be identified by, for example, a serial number. In other words, voltage sensor 122 includes different individual sensors such as voltage sensor 122a, voltage sensor 122b, and voltage sensor 122c, even if they are the same type of sensor. In the following description, they will be referred to as voltage sensor 122a and current sensor 125b to clearly indicate that they are specific individual sensors.

[0013] In this embodiment, the characteristic information includes disturbance noise information and sensor degradation information in addition to the temperature characteristic information. Here, the temperature characteristic information is information that represents a measurement error of the sensor caused by temperature characteristics. The disturbance noise information is information that represents a measurement error of the sensor caused by the addition of noise from the outside. Moreover, the degradation information is information that represents the degree of progress of degradation of the sensor. In this disclosure, the characteristic information is acquired in the form of a map, and is therefore called map information MP. That is, the QR code 123 has map information MPa related to the temperature characteristic information, disturbance noise information, and degradation information of the voltage sensor 122a. Moreover, the QR code 126 has map information MPb related to the temperature characteristic information, disturbance noise information, and degradation information of the current sensor 125b. Here, the map information MPa is information specific to the voltage sensor 122a, and is different from information held by the voltage sensor 122b, which is another individual of the voltage sensor 122. Moreover, the map information MPa is different from information held by the voltage sensor 122 as a set of individuals. In the following description, when there is no need to distinguish between the map information MPa and the map information MPb, they will simply be referred to as "map information MP." Note that the map information MP may include information other than the temperature characteristic information, the deterioration information, and the disturbance noise information.

[0014] The map information MP of the sensor is obtained when the sensor is manufactured, encoded into a QR code, and marked on the sensor. In this embodiment, the map information MPa of the voltage sensor 122a is obtained when the voltage sensor 122 is manufactured, encoded into a QR code 123, and marked on the voltage sensor 122a. The map information MPb of the current sensor 125b is obtained when the current sensor 125 is manufactured, encoded into a QR code 126, and marked on the current sensor 125b. Note that the process of encoding the map information MP of the sensor into a QR code and marking it on each sensor can be omitted.

[0015] The QR code reader 200 reads and decodes the QR code marked on the sensor. In this embodiment, the QR code reader 200 reads and decodes the QR code 123 marked on the voltage sensor 122a and the QR code 126 marked on the current sensor 125b, thereby acquiring the corresponding map information MPa and map information MPb. In addition, the QR code reader 200 transmits the acquired map information MPa and map information MPb to the rewriting tool 300 by wireless communication. In this embodiment, the QR code reader 200 is a handy terminal type carried by a person in charge at the time of manufacturing the battery pack 100. Note that the QR code reader 200 is not limited to the above form. In addition, the QR code reader 200 may read at least one of the QR code 123 marked on the voltage sensor 122a and the QR code 126 marked on the current sensor 125b, and acquire the corresponding map information MP.

[0016] The rewriting tool 300 is configured by a computer. The rewriting tool 300 includes a processor 301, a memory 302, an input / output interface 303, and an internal bus 304. The processor 301, the memory 302, and the input / output interface 303 are connected to each other via the internal bus 304 so as to be able to communicate with each other. A communication device 305 for communicating with the vehicle 1 by wireless communication is connected to the input / output interface 303.

[0017] In this embodiment, the processor 301 executes a program PG2 pre-stored in the memory 302 to function as a map information acquisition unit 310 and a command generation unit 320.

[0018] The map information acquisition unit 310 acquires the map information MPa and the map information MPb received from the QR code reading device 200 .

[0019] The command generating unit 320 generates a command for reflecting the map information MPa and map information MPb acquired by the map information acquiring unit 310 in the battery ECU 130, and transmits the command to the vehicle 1. More specifically, the rewriting tool 300 generates a command for storing the acquired map information MPa and map information MPb in the memory 135 of the battery ECU 130.

[0020] FIG. 2 is a diagram showing an example of map information MP. FIG. 2 shows map information MPa of voltage sensor 122a. In this embodiment, map information MPa is obtained by calculating the measurement error of voltage sensor 122a by measuring in advance, through experiments, the power supply voltage V0 at different temperatures and the voltage V measured by voltage sensor 122a. As described above, map information MPa includes disturbance noise information and sensor degradation information in addition to temperature characteristic information. In this embodiment, degradation information is the number of years that have passed since the manufacture of voltage sensor 122a. However, degradation information is not limited to this.

[0021] In FIG. 2, S1 represents a measurement error caused by the temperature characteristics of voltage sensor 122a. Error S1 includes an element error of voltage sensor 122a. Here, the element error is an error caused by the sensor element of voltage sensor 122a, and is a value specific to voltage sensor 122a. Error S1 is the above-mentioned temperature characteristic information. S2 represents a measurement error caused by the temperature characteristics of voltage sensor 122a and disturbance noise. Like error S1, error S2 also includes an element error of voltage sensor 122a. Error S2 is the above-mentioned temperature characteristic information and disturbance noise information. S3 represents a measurement error caused by aging deterioration of voltage sensor 122a. Error S3 is the above-mentioned deterioration information.

[0022] As described above, the battery ECU 130 calculates the battery state of the battery 110, that is, the SOC and the battery capacity. The SOC can be estimated based on, for example, the circuit voltage (OCV) of the battery 110. Specifically, the battery ECU 130 calculates the SOC using an OCV-SOC curve stored as a map MP1 in the memory 135. The battery capacity can be estimated by integrating the charge / discharge current of the battery 110. That is, when the battery ECU 130 calculates the SOC and the battery capacity of the battery 110, the calculations are performed based on the values ​​of the voltage sensor 122 and the current sensor 125. Note that the battery ECU 130 is designed to calculate the SOC and the battery capacity assuming the measurement errors of the voltage sensor 122 and the current sensor 125, and therefore the estimation accuracy of the SOC and the battery capacity decreases when the measurement errors of the sensors become large. On the other hand, the voltage sensor 122 and the current sensor 125 have large element errors due to manufacturing variations, and there are also large individual differences in the measurement errors due to temperature characteristics, external noise, and deterioration states. That is, even in the same type of voltage sensor 122, the measurement error of the voltage sensor 122a due to the element error, temperature characteristics, disturbance noise, and deterioration state may be significantly different from the measurement error of the voltage sensor 122b due to the element error, temperature characteristics, disturbance noise, and deterioration state. On the other hand, the measurement error of the sensor due to the temperature characteristics of the voltage sensor 122 is usually calculated from a plurality of individual sensors such as the voltage sensor 122a, the voltage sensor 122b, and the voltage sensor 122c. Therefore, there is a problem that the measurement error of the sensor due to the temperature characteristics of the voltage sensor 122 becomes large due to the influence of individual differences. The same is true for the measurement error due to the disturbance noise and deterioration state. Similarly, there is a problem with the current sensor 125 that the measurement error due to the temperature characteristics, disturbance noise, and deterioration state becomes large due to the influence of individual differences. Furthermore, the measurement accuracy of the voltage sensor 122 and the current sensor 125 decreases, and the estimation accuracy of the battery state also decreases.

[0023] In this embodiment, when the battery ECU 130 estimates the battery state of the battery 110, the measurement error of the sensor can be reduced by reflecting the individual characteristics of the voltage sensor 122a or the current sensor 125b, and the estimation accuracy of the battery state can be improved. For example, in the case of the voltage sensor 122a, map information MPa as shown in FIG. 2 is first obtained during the manufacturing process of the voltage sensor 122a, and a QR code 123 having the map information MPa is imprinted on the voltage sensor 122a. Then, during the manufacturing process of the battery pack 100, the QR code reader 200 reads the QR code 123 imprinted on the voltage sensor 122a and transmits the obtained map information MPa to the rewriting tool 300. Then, when the battery pack 100 is mounted on the vehicle 1, the rewriting tool 300 transmits a command to the vehicle 1 to store the obtained map information MPa in the memory 135 of the battery ECU 130 mounted on the vehicle 1. Therefore, the battery ECU 130 of the battery pack 100 equipped with the voltage sensor 122a stores map information MPa of the voltage sensor 122a. Since the map information MPa includes characteristic information of the individual voltage sensor 122a, for example, the error S1 shown in FIG. 2 is smaller than the error acquired from the voltage sensor 122 including the other individual voltage sensors 122b and 122c. The same is true for the current sensor 125. As a result, when the battery ECU 130 calculates the SOC and battery capacity of the battery 110 while assuming the sensor measurement errors of the voltage sensor 122a and the current sensor 125b, the sensor measurement errors can be reduced, and the estimation accuracy can be improved.

[0024] According to the first embodiment described above, characteristic information that is information on errors due to changes in sensor characteristics can be acquired for each individual voltage sensor 122 and current sensor 125 mounted on vehicle 1. This makes it possible to improve the measurement accuracy of voltage sensor 122 and current sensor 125. Furthermore, it is possible to improve the estimation accuracy of the battery state of vehicle 1.

[0025] B. Other embodiments: (B1) In the first embodiment described above, the characteristic information is acquired as map information MP. However, the characteristic information does not have to be acquired as map information MP, and may be acquired as information such as a mathematical formula.

[0026] (B2) In the first embodiment described above, the system 400 includes the QR code reading device 200 and the rewriting tool 300. However, the functions of the QR code reading device 200 and the rewriting tool 300 may be implemented in the same device.

[0027] (B3) In the above-described first embodiment, the map information MP is stored in the QR code 123 imprinted on the voltage sensor 122 and the QR code 126 imprinted on the current sensor 125. In contrast, the map information MP does not have to be stored in the QR code 123 or the QR code 126. For example, the map information MP may be aggregated in a cloud environment. In this case, information may be written from the cloud to the battery ECU 130 of the vehicle 1 on which each sensor is mounted, using OTA (Over The Air) technology.

[0028] The present disclosure is not limited to the above-mentioned embodiment, and can be realized in various configurations without departing from the spirit of the present disclosure. For example, the technical features of the embodiments corresponding to the technical features in each aspect described in the Summary of the Invention can be appropriately replaced or combined to solve some or all of the above-mentioned problems or to achieve some or all of the above-mentioned effects. Furthermore, if a technical feature is not described as essential in this specification, it can be appropriately deleted. [Explanation of symbols]

[0029] 1...vehicle, 100...battery pack, 110...battery, 112...secondary battery, 120...monitoring unit, 122...voltage sensor, 125...current sensor, 123, 126...QR code, 128...temperature sensor, 130...battery ECU, 132...processor, 135...memory, 200...QR code reader, 300...rewrite tool, 301...processor, 302...memory, 303...input / output interface, 304...internal bus, 305...communication device, 310...map information acquisition unit, 320...command generation unit, 400...system, MP, MPa, MPb...map information, IB...current, TB...temperature, VB...voltage, PG1, PG2...program, S1, S2, S3...error

Claims

[Claim 1] A system for estimating a battery state of a battery used to drive a moving object, comprising: a two-dimensional code having characteristic information including temperature characteristic information corresponding to an individual sensor of at least one of a voltage sensor for measuring a voltage of the battery and a current sensor for measuring a current of the battery, the two-dimensional code being engraved on the sensor; a rewriting tool that acquires the characteristic information by reading the two-dimensional code and reflects the characteristic information in a memory unit of a control unit.

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