Battery discrimination method

Abstract

A battery discrimination method suppresses cost and detects a case where a battery module of a different kind is erroneously assembled at the time of manufacturing of a battery pack. The battery discrimination method is implemented for a battery module at the time of manufacturing of a battery pack, and includes a measurement step of measuring a voltage of a temperature measurement circuit for measuring a temperature of a bus bar provided in the battery module in a state where no current flows in the bus bar when the battery module is mounted in a case of the battery pack, a presumption step of presuming an internal resistance of a thermistor connected to the temperature measurement circuit based on a measured value of the voltage, a calculation step of calculating the voltage of the temperature measurement circuit based on the presumed value of the internal resistance and a resistance value of a discrimination resistance provided in the temperature measurement circuit, and a determination step of determining whether or not the battery module is a genuine product by comparing a calculated value of the voltage with the measured value of the voltage.

Description

Technical Field

[0001] This invention relates to a battery identification method. Background Technology

[0002] Patent Document 1 discloses a monitoring unit that monitors whether a battery module containing multiple battery cells is genuine. This monitoring unit determines whether the battery module is genuine based on identification information stored in a storage unit within the battery module.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2012-85470 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] However, in the configuration described in Patent Document 1, during the manufacturing of the battery pack, the battery modules are assembled into the battery pack housing, and after communication is established between the monitoring unit and the storage unit, registration is performed based on the identification information from the monitoring unit. Therefore, if a battery module different from the genuine product is mistakenly connected during the initial connection between the battery module and the monitoring unit, the monitoring unit cannot determine that the battery module is a counterfeit. Furthermore, a storage circuit is required for each battery module to store information indicating that the battery module is genuine, increasing costs.

[0008] The present invention was made in view of the above circumstances, and its object is to provide a battery identification method that can suppress costs and detect the situation where different types of battery modules are incorrectly assembled during the manufacturing of battery packs.

[0009] Methods for solving problems

[0010] This invention relates to a battery identification method implemented on battery modules during the manufacturing of a battery pack. The method is characterized by comprising: a measurement step, wherein, when the battery module is mounted on the housing of the battery pack, a voltage of a temperature measuring circuit used to measure the temperature of the busbar is measured in a state where no current flows in the busbar of the battery module; an estimation step, wherein the internal resistance of a thermistor connected to the temperature measuring circuit is estimated based on the measured voltage value; a calculation step, wherein the voltage of the temperature measuring circuit is calculated based on the estimated internal resistance value and the resistance value of a identification resistor provided in the temperature measuring circuit; and a determination step, wherein the calculated voltage value and the measured voltage value are compared to determine whether the battery module is genuine.

[0011] Invention Effects

[0012] In this invention, costs can be suppressed and the situation where different types of battery modules are incorrectly assembled can be detected during the manufacturing of the battery pack. Attached Figure Description

[0013] Figure 1 This is a schematic diagram illustrating the battery module in the embodiment.

[0014] Figure 2 This is a diagram used to illustrate a temperature measurement circuit.

[0015] Figure 3 This is a diagram used to illustrate the battery ECU and its circuitry.

[0016] Figure 4 This is a flowchart illustrating the battery identification process.

[0017] Figure 5 This is a diagram used to illustrate the battery ECU and circuit configuration in the modified example. Detailed Implementation

[0018] The battery identification method in the embodiments of the present invention will be described in detail below. However, the present invention is not limited to the embodiments described below.

[0019] Figure 1 This diagram schematically illustrates the battery module in the embodiment. Battery module 1 serves as the object for identifying the type of battery. Battery module 1 is included in a battery pack. The battery pack is installed in electric vehicles, hybrid vehicles, and other electric vehicles.

[0020] The battery module 1 has multiple battery cells 2, multiple busbars 3, and two thermistors 4.

[0021] Battery cell 2 is a square cell. Battery cell 2 is composed of lithium-ion rechargeable batteries. In battery module 1, multiple battery cells 2 are arranged in a first direction. Battery module 1 has a stack of multiple battery cells 2 stacked in the first direction. Adjacent battery cells 2 in the first direction are electrically connected to each other through busbars 3. Battery module 1 is a battery pack in which multiple battery cells 2 are electrically connected in series through multiple busbars 3.

[0022] Busbar 3 is a metal component that connects to the terminals of the battery cell 2. For example, busbar 3 is made of copper plate. Busbar 3 connects to the terminals of adjacent battery cells 2, electrically connecting the adjacent battery cells 2 to each other.

[0023] Thermistor 4 is an NTC thermistor used to measure the temperature of busbar 3. Thermistor 4 is a busbar thermistor installed on busbar 3 to measure the temperature of busbar 3 caused by the current flowing through it.

[0024] In a battery module 1, a thermistor 4 is provided on any two of the multiple busbars 3. For example Figure 2 As shown, the multiple busbars 3 include a first busbar 3A and a second busbar 3B. The two thermistors 4 include a first thermistor 4A disposed in the first busbar 3A and a second thermistor 4B disposed in the second busbar 3B.

[0025] Battery module 1 is controlled by battery ECU 10.

[0026] The battery ECU 10 is an electronic control device that controls the battery module 1. The battery ECU 10 includes a processor and a memory. The battery ECU 10 loads programs stored in the storage unit into the operating area of ​​the memory and executes them. Through program execution, it controls various components, thereby achieving functions that meet the specified purpose. Signals from various sensors are input to the battery ECU 10. Signals from a voltage sensor that detects the voltage of the battery cell 2, signals from a temperature sensor that detects the temperature of the battery cell 2, and signals from a thermistor 4 are input to the battery ECU 10. The thermistor 4 is connected to the battery ECU 10 via a wiring harness 21. The battery ECU 10 performs battery control based on the signals input from the various sensors. The battery ECU 10 measures the voltage of the battery cell 2, the temperature of the battery cell 2, and the temperature of the busbar 3, and controls the battery module 1 based on this information.

[0027] The battery ECU 10 is connected to a temperature measuring circuit 5 that measures the temperature of the busbars 3. The temperature measuring circuit 5 measures the temperature of the busbars 3 at two or more measurement points on different busbars 3, connecting the individual battery cells 2 to each other. Figure 2 In the example shown, the temperature measuring circuit 5 includes a first temperature measuring circuit 5A for measuring the temperature of the first busbar 3A and a second temperature measuring circuit 5B for measuring the temperature of the second busbar 3B. A first thermistor 4A is connected to the first temperature measuring circuit 5A. A second thermistor 4B is connected to the second temperature measuring circuit 5B.

[0028] The battery ECU 10 is connected to either of the two thermistors 4 via a discrimination resistor 22. In this embodiment, the battery ECU 10 is connected to the first thermistor 4A via the discrimination resistor 22. The discrimination resistor 22 is provided in the first temperature measuring circuit 5A.

[0029] The identification resistor 22 is used to identify the type of battery. The identification resistor 22 has a resistance value determined by the type of battery cell 2. The resistance value of the identification resistor 22 is predetermined based on the type of battery cell 2. The constant of the identification resistor 22 affects the measurement results of the thermistor 4, therefore it is set to a constant within a range that will not cause any influence. The wiring harness 21 connects the thermistor 4 to the battery ECU 10, connects the thermistor 4 to the identification resistor 22, and connects the identification resistor 22 to the battery ECU 10.

[0030] like Figure 3 As shown, the battery ECU 10 includes a microcomputer 11. The microcomputer 11 includes an A / D converter 12, a determination unit 13, and a storage unit 14. The microcomputer 11 processes, determines, and stores the input signals. The microcomputer 11 measures and determines the voltage of the battery cell 2, the temperature of the battery cell 2, the temperature of the busbar 3, and the state of the discrimination signal. The A / D converter 12 converts analog data related to the temperature of the busbar 3 into digital data. The determination unit 13 makes a determination based on the digital signal. The storage unit 14 stores the information.

[0031] The battery ECU 10 includes a power supply 15 and a pull-up resistor 16. The power supply 15 is used for thermistor measurement. The pull-up resistor 16 is used to fix the signal state. The power supply 15 is connected to an auxiliary battery installed in an electric vehicle equipped with a battery pack. The pull-up resistor 16 is connected to the power supply 15. The microcomputer 11 is connected to the power supply 15 via the pull-up resistor 16.

[0032] The microcomputer 11 operates by power supplied from the power source 15. The microcomputer 11 is connected to the temperature measuring circuit 5 and measures the voltage of the temperature measuring circuit 5. The microcomputer 11 measures the voltage of the first temperature measuring circuit 5A, i.e., the first voltage VA, and measures the voltage of the second temperature measuring circuit 5B, i.e., the second voltage VB.

[0033] In battery pack manufacturing plants, battery packs are sometimes manufactured that contain battery modules of a different type than battery module 1. For example, as regular battery cells processed in such plants, there are sometimes multiple battery cells that, although identical in appearance to battery cell 2, have different internal properties than battery cell 2. In this case, the manufacturing plant manufactures multiple battery modules that, although identical in appearance to battery module 1, have different charging and discharging characteristics due to the different properties of the battery cells.

[0034] Furthermore, if the physical properties of a single battery cell change, the control conditions for the safe use of the battery module will differ. Therefore, it is necessary to implement controls suitable for the battery cells in the product state. Thus, it is desirable to be able to determine whether a battery module is genuine during the manufacturing process of the battery pack. Therefore, the battery identification method in this embodiment is configured to detect, during the battery pack manufacturing process, the possibility that a battery module of a different type than battery module 1 has been incorrectly assembled.

[0035] The battery identification method of this embodiment is based on the resistance value of the identification resistor 22 to easily determine whether it is the correct battery envisioned in the battery ECU 10. In the prior art, a storage circuit for battery identification is set in the battery module as a dedicated circuit, but in this embodiment, this storage circuit is not required, which simplifies the identification signal, reduces the number of terminals, and suppresses costs. In addition, it is possible to detect battery module mounting errors that may occur during the manufacturing process.

[0036] Specifically, for a battery module 1, at least two thermistors 4 for measuring busbar temperature are installed, and a discrimination resistor 22 for identifying the type of battery is installed between one of the thermistors 4 and the battery ECU 10. By measuring the resistance value of the discrimination resistor 22, the battery ECU 10 determines whether it is the intended battery or a different battery. If it is a different battery, the battery ECU 10 can disable the battery module. Furthermore, although the discrimination resistor 22 may affect the measurement results of the thermistor 4, by including the discrimination resistor 22 in the temperature measuring circuit 5 used to determine whether the temperature has exceeded the threshold, the impact on its control can be reduced.

[0037] Figure 4 This is a flowchart illustrating the battery identification process. Figure 4 The battery identification process shown is implemented during the manufacturing of the battery pack.

[0038] In the battery pack manufacturing process, the battery module 1 is mounted on the battery pack housing (step S1). The battery pack manufacturing method includes a mounting process. Step S1 is the mounting process. The mounting process is the process of placing the battery module 1 on the lower housing of the battery pack. The battery pack housing has an upper cover and a lower housing. In step S1, the battery module 1 is mounted inside the lower housing.

[0039] In the measurement steps included in the battery identification method, the microcomputer 11 is powered on to measure the voltage of the temperature measuring circuit 5 when there is no current flowing in the busbar 3 included in the battery module 1 (step S2). In step S2, with the battery ECU 10 connected to the thermistor 4 via the wiring harness 21 and no current flowing in the busbar 3, the microcomputer 11 is powered by the auxiliary battery, and the microcomputer 11 measures the voltage of the temperature measuring circuit 5. At this time, the microcomputer 11 measures the first voltage VA and the second voltage VB as the voltage of the temperature measuring circuit 5.

[0040] In the estimation step included in the battery identification method, the resistance value of the internal resistance R1 of the first thermistor 4A is estimated based on the measured value of the second voltage VB and the estimation mapping (step S3). The estimation mapping used in step S3 is a mapping stored in the storage unit 14, which represents the relationship between the voltage VB of the second temperature measuring circuit 5B and the resistance value of the internal resistance R1 of the first thermistor 4A. In step S3, the microcomputer 11 calculates the estimated value of the resistance value of the internal resistance R1 based on the measured value of the second voltage VB and the estimation mapping stored in the storage unit 14.

[0041] During the implementation of the battery identification method, since there is no current flowing in the busbar 3, the microcomputer 11 considers the internal resistance R1 of the first thermistor 4A and the internal resistance R2 of the second thermistor 4B to be the same resistance value (step S4). When there is no current flowing in the busbar 3 of the battery module 1, the difference between the resistance value of the internal resistance R1 of the first thermistor 4A and the resistance value of the internal resistance R2 of the second thermistor 4B is within the error range.

[0042] In the calculation steps included in the battery identification method, the first voltage VA of the first temperature measuring circuit 5A is calculated based on the resistance value of the identification resistor 22 installed in the correct battery module 1 and the estimated value of the internal resistance R1 (step S5). In step S5, the microcomputer 11 calculates the value of the first voltage VA. The microcomputer 11 uses the value obtained by adding the resistance value of the identification resistor 22 to the estimated value of the internal resistance R1 to calculate the first voltage VA.

[0043] In the determination step included in the battery identification method, it is determined whether the calculated value of the first voltage VA is equal to the measured value of the first voltage VA (step S6). In step S6, the microcomputer 11 compares the calculated value of the first voltage VA with the measured value of the first voltage VA to determine whether the battery module 1 is genuine. For example, it determines whether the calculated value of the first voltage VA is the same as the measured value of the first voltage VA.

[0044] If the calculated value of the first voltage VA is equal to the measured value of the first voltage VA (step S6: Yes), the microcomputer 11 determines that the correct battery module 1 is installed and allows the battery module 1 to start (step S7). After the processing of step S7 is performed, the battery identification process ends.

[0045] If the calculated value of the first voltage VA is not equal to the measured value of the first voltage VA (step S6: No), the microcomputer 11 determines that the correct battery module 1 is not installed and does not allow the battery module 1 to start (step S8). After the processing of step S8 is implemented, the battery identification process ends.

[0046] As explained above, according to the embodiment, a discrimination resistor 22 can be provided between the thermistor 4, which measures the temperature of the busbar 3, and the battery ECU 10, without increasing the number of wires in the harness 21. Therefore, it is possible to distinguish the type of battery for the battery module 1 while suppressing costs.

[0047] Furthermore, any configuration consisting of multiple temperature measuring circuits 5 connected to the battery ECU 10 is acceptable, and the number of temperature measuring circuits 5 is not limited to two. Two or more temperature measuring circuits 5 are permissible, and any one of the temperature measuring circuits 5 may include a discrimination resistor 22.

[0048] Alternatively, as a variation, it can also be determined using a simpler tool different from the battery ECU 10. For example, such as... Figure 5 As shown, instead of the battery ECU 10, the battery state is measured by a battery monitoring unit 30 equipped with an IC 31 for measuring the battery state. The battery monitoring unit 30 includes the IC 31 and a communication unit 32. The IC 31 includes an A / D converter 33. The communication unit 32 communicates with the battery ECU 10. The battery monitoring unit 30 is configured to communicate with the battery ECU 10. Additionally, the battery monitoring unit 30 includes a power supply 34 and a pull-up resistor 35. The battery ECU 10 includes a microcomputer 11 and a communication unit 17. The microcomputer 11 includes a determination unit 13 and a storage unit 14. The communication unit 17 communicates with the battery monitoring unit 30. The battery monitoring unit 30 measures the battery state and sends the measurement results to the battery ECU 10. The battery ECU 10 determines whether the battery module 1 is genuine based on the information sent from the battery monitoring unit 30.

[0049] Explanation of reference numerals in the attached figures

[0050] 1 Battery Module

[0051] 2. Battery cell

[0052] 3. Busbar

[0053] 3A First Busbar

[0054] 3B Second Busbar

[0055] 4. Thermistor

[0056] 4A First Thermistor

[0057] 4B Second Thermistor

[0058] 10 Battery ECU

[0059] 11 Microcomputer

[0060] 12 A / D Conversion Unit

[0061] 13 Judgment Department

[0062] 14 Storage Department

Claims

1. A battery identification method, implemented during the manufacturing of a battery pack for battery modules, characterized in that, The battery identification method includes: The measurement step involves measuring the voltage of a temperature measuring circuit used to measure the temperature of the busbar when the battery module is mounted on the housing of the battery pack, with no current flowing in the busbar of the battery module. The estimation step involves estimating the internal resistance of the thermistor connected to the temperature measuring circuit based on the measured value of the voltage. The calculation step involves calculating the voltage of the temperature measuring circuit based on the estimated value of the internal resistance and the resistance value of the discrimination resistor set in the temperature measuring circuit. as well as The determination step involves comparing the calculated voltage value with the measured voltage value to determine whether the battery module is genuine.

2. The battery identification method according to claim 1, characterized in that, The estimation step includes estimating the internal resistance based on a mapping representing the relationship between the voltage and the internal resistance, and a measured value of the voltage.

3. The battery identification method according to claim 2, characterized in that, The busbar includes a first busbar and a second busbar. The thermistor includes a first thermistor disposed in the first busbar and a second thermistor disposed in the second busbar. The temperature measuring circuit includes a first temperature measuring circuit connected to the first thermistor and a second temperature measuring circuit connected to the second thermistor. The discrimination resistor is set in the first temperature measuring circuit. The mapping represents the relationship between the voltage of the second temperature measuring circuit (i.e., the second voltage) and the internal resistance of the first thermistor. The measurement step includes measuring the voltage of the first temperature measuring circuit, i.e., the first voltage, and the second voltage as the voltage. The estimation step includes estimating the internal resistance of the first thermistor based on the measured value of the second voltage and the mapping. The calculation step includes calculating the first voltage based on the estimated value of the internal resistance of the first thermistor and the resistance value of the discrimination resistor. The determination step includes comparing the calculated value of the first voltage with the measured value of the first voltage to determine whether the battery module is genuine.

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