Battery monitoring device

Abstract

A battery monitoring device includes: an SOC sensor that detects an SOC of a battery; an ambient temperature sensor that detects an ambient temperature of the battery; a load sensor that detects a constraint load of the battery; a battery temperature sensor that detects the temperature of the battery; and an ECU that determines an operation cycle of the battery temperature sensor based on the SOC, the ambient temperature, and the constraint load, and operates the battery temperature sensor in the determined operation cycle.

Description

Technical Field

[0001] This disclosure relates to a battery monitoring device. Background Technology

[0002] Japanese Unexamined Patent Application Publication No. 2021-036485 (JP 2021-036485 A) describes a method for cooling a power supply device, the method including detecting the state of charge (SOC) of a battery and the ambient temperature, determining whether a predetermined temperature evaluation criterion is met based on the detected SOC and temperature, and operating a cooling mechanism for cooling the battery when it is determined that the temperature evaluation criterion is not met. Summary of the Invention

[0003] The cooling method described in JP 2021-036485 A uses only the battery's SOC and ambient temperature for temperature assessment, and there is room for improvement in terms of accuracy.

[0004] The following issues exist: the risk of smoke generation increases when the interval for detecting battery temperature is long, and power consumption also increases when the interval for detecting battery temperature is long.

[0005] The purpose of this disclosure is to provide a battery monitoring device capable of detecting the temperature of a battery at appropriate time intervals.

[0006] One aspect of this disclosure provides a battery monitoring device, comprising: a state of charge (SOC) sensor that detects the SOC of a battery; an ambient temperature sensor that detects the ambient temperature of the battery; a load sensor that detects the constraint load on the battery; a battery temperature sensor that detects the temperature of the battery; and a control device that determines the operating cycle of the battery temperature sensor based on the SOC, ambient temperature, and constraint load, and operates the battery temperature sensor during the determined operating cycle.

[0007] According to this disclosure, the temperature of the battery can be detected at appropriate time intervals. Attached Figure Description

[0008] The features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will now be described with reference to the accompanying drawings, wherein similar symbols denote similar elements, and wherein: Figure 1 The overall configuration of a vehicle equipped with a battery cooling device according to an embodiment is schematically shown; Figure 2A An example illustrating the risk of smoke generation from battery 5; Figure 2B An example illustrating the risk of smoke generation from battery 5; Figure 2CAn example illustrating the risk of smoke generation from battery 5; Figure 3 An example showing the temperature check of battery 5 TB; and Figure 4 This is a flowchart illustrating the monitoring process used to control battery 5. Detailed Implementation

[0009] The embodiments will now be described with reference to the accompanying drawings. Figure 1 The overall configuration of a vehicle equipped with a battery cooling device according to an embodiment is schematically shown. Vehicle 1 is, for example, a battery electric vehicle. Vehicle 1 is configured to allow external charging (so-called plug-in charging) in which power is supplied to vehicle 1 from a charger (not shown) to charge the on-board battery 5. Vehicle 1 should be configured so that external charging is not required. Vehicle 1 can be a conventional hybrid electric vehicle that is not externally charged.

[0010] Vehicle 1 includes an entrance 2, charging cables PL1 and NL1, a voltage sensor 31, a current sensor 32, charging relays 41 and 42, a system main relay (SMR) 43 and 44, power lines PL2 and NL2, a battery 5, a state of charge (SOC) sensor 61, an ambient temperature sensor 63, a load sensor 62, a battery temperature sensor 64, a cooling device 7, a power control unit (PCU) 81, a motor generator 82, a power transmission gear 83, drive wheels 84, and an electronic control unit (ECU) 10.

[0011] The SOC sensor 61, ambient temperature sensor 63, load sensor 62, battery temperature sensor 64, and ECU 10 constitute the battery monitoring device 200.

[0012] The inlet (charging port) 2 is configured to allow insertion of a connector (not shown) into the charging cable via mechanical coupling (such as mating).

[0013] Voltage sensor 31 is electrically connected to charging cable PL1 and charging cable NL1 on the inlet 2 side relative to charging relay 41. Voltage sensor 31 detects the direct current (DC) voltage between charging cable PL1 and charging cable NL1 and outputs the detection result to ECU 10. Current sensor 32 is provided, for example, in charging cable PL1. Current sensor 32 detects the current flowing through charging cable PL1 and outputs the detection result to ECU 10. ECU 10 can calculate the amount of power supplied from the charger (not shown) (charge amount of battery 5) based on the detection results from voltage sensor 31 and current sensor 32.

[0014] Charging relay 41 is connected to charging cable PL1, and charging relay 42 is connected to charging cable NL1. The opening and closing of charging relays 41 and 42 are controlled by commands from ECU 10. When charging relays 41 and 42 are closed and SMRs 43 and 44 are closed, power transfer between inlet 2 and battery 5 is enabled.

[0015] Battery 5 is an assembled battery comprising multiple battery cells 50. Each battery cell 50 is a lithium-ion secondary battery. Battery 5 supplies power to generate driving force for vehicle 1. Additionally, battery 5 stores power generated by motor generator 82. The positive terminal of battery 5 is electrically connected to node ND1 via SMR 43. Node ND1 is electrically connected to charging line PL1 and power line PL2. Similarly, the negative terminal of battery 5 is electrically connected to node ND2 via SMR 44. Node ND2 is electrically connected to charging line NL1 and power line NL2. The opening / closing of SMR 43 and 44 is controlled according to commands from ECU 10.

[0016] The cooling device 7 is, for example, a liquid-cooled cooling device that uses liquid refrigerant. The cooling device 7 cools the battery 5 according to commands from the ECU 10.

[0017] PCU 81 is electrically connected between power lines PL2, NL2 and motor generator 82. PCU 81 includes a converter and an inverter (both not shown) and drives motor generator 82 according to commands from ECU 10.

[0018] The motor generator 82 is an alternating current (AC) rotary motor, such as a permanent magnet synchronous motor including a rotor in which permanent magnets are embedded. The output torque of the motor generator 82 is transmitted to the drive wheel 84 via the power transmission gear 83, causing the vehicle 1 to move. Furthermore, when the vehicle 1 brakes, the motor generator 82 can generate electricity using the rotational force of the drive wheel 84. The electricity generated by the motor generator 82 is converted by the PCU 81 into charging power for the battery 5.

[0019] The ECU 10 includes a processor 11 such as a central processing unit (CPU), a memory 12 such as read-only memory (ROM) and random access memory (RAM), and input / output ports 13. The ECU 10 controls the device based on signals from various sensors, etc., to bring the vehicle 1 into a desired state. The ECU 10 can be divided into multiple ECUs (such as a battery ECU, a motor generator (MG) ECU, etc.) for corresponding functions.

[0020] SOC sensor 61 detects the SOC of battery 5. SOC sensor 61 can directly detect the SOC of battery 5. SOC sensor can detect the voltage VB of battery 5 and the current IB input to and output from battery 5, and detect the SOC of battery 5 based on voltage VB and current IB.

[0021] The ambient temperature sensor 63 detects the ambient temperature TA of the battery 5. The ambient temperature sensor 63 can directly detect the ambient temperature TA of the battery 5. The ambient temperature sensor 63 can detect the current IB input to and output from the battery 5, and detect the ambient temperature TA of the battery 5 based on the current IB.

[0022] Load sensor 62 detects the constraint load FA of battery 5. For example, load sensor 62 can be clamped between the individual battery cells 50 of battery 5 to detect the constraint load FA of battery 5.

[0023] Battery temperature sensor 64 detects the temperature TB of battery 5. Battery temperature sensor 64 operates intermittently.

[0024] Figure 2A , Figure 2B and Figure 2C Each example illustrates the risk of smoke generation from battery 5. For example... Figure 2A As shown, the risk of smoke generation from battery 5 increases with the increase of the state of charge (SOC) of battery 5. Figure 2B As shown, the risk of smoke generation from battery 5 increases with the increase of the ambient temperature TA of battery 5. Figure 2C As shown, as the constraint load FA of battery 5 increases, the risk of smoke generation from battery 5 increases.

[0025] Figure 3 An example of checking the temperature of battery 5 TB is shown. When the risk of smoke from the battery increases, the interval for checking the temperature of battery 5 TB needs to be shortened.

[0026] In this embodiment, the cycle for operating the battery temperature sensor 64 to detect the temperature TB of the battery 5 is determined based on the above considerations.

[0027] ECU 10 determines the operating cycle of battery temperature sensor 64 based on the state of charge (SOC) of battery 5, the ambient temperature (TA) of battery 5, and the constraint load (FA) of battery 5. ECU 10 operates battery temperature sensor 64 during the determined operating cycle. Cooling device 7 is controlled based on the temperature (TB) of battery 5 detected by battery temperature sensor 64.

[0028] ECU 10 calculates variable α based on the SOC of battery 5, variable β based on the ambient temperature TA of battery 5, and variable γ based on the constraint load FA of battery 5. The operating cycle of battery temperature sensor 64 increases as the sum of variables α, β and γ increases.

[0029] When the SOC of battery 5 is in the first range, ECU 10 sets variable α to a first value; when the SOC of battery 5 is in the second range greater than the first range, it sets variable α to a second value less than the first value; and when the SOC of battery 5 is in the third range greater than the second range, it sets variable α to a third value less than the second value. When the ambient temperature TA of battery 5 is within the first range, ECU 10 sets variable β to a first value; when the ambient temperature TA of battery 5 is within the second range greater than the first range, it sets variable β to a second value less than the first value; and when the ambient temperature TA of battery 5 is within the third range greater than the second range, it sets variable β to a third value less than the second value.

[0030] When the constraint load FA of battery 5 is within the first range, ECU 10 sets the variable γ to a first value; when the constraint load FA of battery 5 is within the second range greater than the first range, it sets the variable γ to a second value less than the first value; and when the constraint load FA of battery 5 is within the third range greater than the second range, it sets the variable γ to a third value less than the second value.

[0031] Figure 4 This is a flowchart illustrating the monitoring process used to control battery 5. In step S101, ECU 10 acquires the SOC of battery 5 detected by SOC sensor 61. When the SOC of battery 5 is 0% to 30%, the process proceeds to step S102; when the SOC of battery 5 is 31% to 70%, the process proceeds to step S103; and when the SOC of battery 5 is 71% to 100%, the process proceeds to step S104.

[0032] In step S102, ECU 10 sets variable α to 2. In step S103, ECU 10 sets variable α to 1.

[0033] In step S104, ECU 10 sets variable α to 0. In step S105, ECU 10 acquires the ambient temperature TA of battery 5 detected by ambient temperature sensor 63. When the ambient temperature TA of battery 5 is between 0°C and 20°C, the process proceeds to step S106; when the ambient temperature TA of battery 5 is between 21°C and 30°C, the process proceeds to step S107; and when the ambient temperature TA of battery 5 is 31°C or higher, the process proceeds to step S108.

[0034] In step S106, ECU 10 sets the variable β to 2. In step S107, ECU 10 sets variable β to 1.

[0035] In step S108, ECU 10 sets variable β to 0. In step S109, ECU 10 acquires the constraint load FA of battery 5 detected by load sensor 62. When the constraint load FA of battery 5 is 1.9 kN or less, the process proceeds to step S110; when the constraint load FA of battery 5 is 2.0 kN to 3.9 kN, the process proceeds to step S111; and when the constraint load FA of battery 5 is 4.0 kN or greater, the process proceeds to step S112.

[0036] In step S110, ECU 10 sets the variable γ to 2. In step S111, ECU 10 sets the variable γ to 1.

[0037] In step S112, ECU 10 sets the variable γ to 0. In step S113, ECU 10 determines the operating interval (activation interval) f[s] of battery temperature sensor 64 by the following equation (1). f=30+10×(α+β+γ)······(1) As described above, according to this embodiment, the operating cycle of the battery temperature sensor is determined based on the battery's SOC, the battery's ambient temperature, and the battery's constraint load, thereby reducing the risk of smoke generation and power consumption with high accuracy.

[0038] The ambient temperature of battery 5 can be used instead of the outside air temperature. The embodiments disclosed herein should be considered exemplary and not restrictive in all respects. The scope of this disclosure is defined by the claims rather than by the foregoing description and is intended to include all modifications falling within the meaning and scope equivalent to that of the claims.

Claims

1. A battery monitoring device, comprising: State of charge (SOC) sensor, which detects the SOC of the battery; An ambient temperature sensor detects the ambient temperature of the battery. A load sensor that detects the constraint load on the battery; A battery temperature sensor that detects the temperature of the battery; as well as A control device that determines the operating cycle of the battery temperature sensor based on the SOC, the ambient temperature, and the constraint load, and operates the battery temperature sensor within the determined operating cycle.

2. The battery monitoring device according to claim 1, wherein, The control device calculates a first variable based on the SOC, a second variable based on the ambient temperature, and a third variable based on the constraint load, and increases the operating cycle as the sum of the first variable, the second variable, and the third variable increases.

3. The battery monitoring device according to claim 2, wherein, When the SOC is within a first range, the control device sets the first variable to a first value; when the SOC is within a second range greater than the first range, the control device sets the first variable to a second value less than the first value; and when the SOC is within a third range greater than the second range, the control device sets the first variable to a third value less than the second value.

4. The battery monitoring device according to claim 2, wherein, When the ambient temperature is within a first range, the control device sets the second variable to a first value; when the ambient temperature is within a second range greater than the first range, the second variable sets the second variable to a second value less than the first value; and when the ambient temperature is within a third range greater than the second range, the second variable sets the second variable to a third value less than the second value.

5. The battery monitoring device according to claim 2, wherein, When the constraint load is within a first range, the control device sets the third variable to a first value; when the constraint load is within a second range greater than the first range, the control device sets the third variable to a second value less than the first value; and when the constraint load is within a third range greater than the second range, the control device sets the third variable to a third value less than the second value.

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