BATTERY MONITORING DEVICE

Abstract

A battery monitoring device comprises: a SOC sensor for detecting the state of charge (SOC) of a battery; an ambient temperature sensor for detecting the ambient temperature of the battery; a load sensor for detecting a retaining load of the battery; a battery temperature sensor for detecting the temperature of the battery; and a control device that determines an operating cycle of the battery temperature sensor based on the SOC, the ambient temperature, and the retaining load, and operates the battery temperature sensor in the determined operating cycle.

Description

BACKGROUND OF THE INVENTION 1. Field of the invention

[0001] The present disclosure relates to a battery monitoring device. 2. Description of the state of the art

[0002] JP 2021-036485 (JP 2021-036485 A) describes a method for cooling a power supply device, the method comprising: sensing a state of charge (SOC) and ambient temperature of a battery, determining whether a predetermined temperature evaluation criterion is met, based on the sensed SOC and temperature, and operating a cooling mechanism that cools the battery when it is determined that the temperature evaluation criterion is not met. BRIEF OVERVIEW OF DETECTION

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

[0004] There is a problem in that the risk of smoke development increases if the interval for detecting the battery temperature is long, and that power consumption increases if the interval for detecting the battery temperature is long.

[0005] The objective of the present disclosure is to provide a battery monitoring device that can detect the temperature of a battery at appropriate times.

[0006] One aspect of the present disclosure provides a battery monitoring device comprising: a state-of-charge (SOC) sensor for detecting the SOC of a battery; an ambient temperature sensor for detecting the ambient temperature of the battery; a load sensor for detecting a retaining load of the battery; a battery temperature sensor for detecting the temperature of the battery; and a control device that determines an operating cycle of the battery temperature sensor based on the SOC, the ambient temperature, and the retaining load, and operates the battery temperature sensor in the determined operating cycle.

[0007] According to the present disclosure, the temperature of a battery can be recorded at suitable times. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The following describes the features, advantages, and technical and industrial significance of exemplary embodiments of the invention with reference to the accompanying drawings, in which the same reference numerals denote the same elements and wherein: Fig. 1 schematically shows the overall configuration of a vehicle equipped with a battery cooling device according to one embodiment; Fig. 2A shows an example of the risk of smoke coming from a battery 5; Fig. Figure 2B shows an example of the risk of smoke development from battery 5; Fig. Figure 2C shows an example of the risk of smoke development from battery 5; Fig. Figure 3 shows an example of controlling the temperature TB of battery 5; and Fig. 4 is a flowchart showing the procedure for controlling the monitoring of battery 5. DETAILED DESCRIPTION OF EXECUTION FORMS

[0009] One embodiment is described below with reference to the drawings.

[0010] Fig. Figure 1 schematically shows the overall configuration of a vehicle equipped with a battery cooling device according to one embodiment. For example, vehicle 1 is a battery-powered electric vehicle. Vehicle 1 is designed to be externally rechargeable (so-called plug-in charging), with current being supplied to vehicle 1 from a charger (not shown) to charge a vehicle battery 5. It is not essential that vehicle 1 be designed to be externally rechargeable. Vehicle 1 can be a conventional hybrid electric vehicle that is not externally rechargeable.

[0011] The vehicle 1 comprises an inlet 2, charging lines PL1, NL1, a voltage sensor 31, a current sensor 32, charging relays 41, 42, system main relays (SMRs) 43, 44, power lines PL2, NL2, the 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 gearbox 83, drive wheels 84 and an electronic control unit (ECU) 10.

[0012] The SOC sensor 61, the ambient temperature sensor 63, the load sensor 62, the battery temperature sensor 64 and the ECU 10 form a battery monitoring device 200.

[0013] The inlet (charging port) 2 is designed to allow the insertion of a connector or plug (not shown) of a charging cable with a mechanical coupling, e.g. a plug connector.

[0014] The voltage sensor 31 is electrically connected between charging line PL1 and charging line NL1, on the side of inlet 2 with respect to the charging relay 41. The voltage sensor 31 detects a DC voltage between charging line PL1 and charging line NL1 and outputs the detection result to the ECU 10. The current sensor 32 is, for example, located in charging line PL1. The current sensor 32 detects a current flowing through charging line PL1 and outputs the detection result to the ECU 10. The ECU 10 can calculate the power supplied by a charger (not shown) (the amount of charge in battery 5) based on the detection results from the voltage sensor 31 and the current sensor 32.

[0015] Charging relay 41 is connected to charging line PL1, and charging relay 42 is connected to charging line NL1. The opening and closing of charging relays 41 and 42 is controlled by a command from ECU 10. When charging relays 41 and 42 are closed and SMRs 43 and 44 are closed, current can flow between inlet 2 and battery 5.

[0016] Battery 5 is a battery unit with multiple cells 50. Each of the cells 50 is a lithium-ion secondary battery. Battery 5 supplies energy to generate drive power for vehicle 1. Furthermore, battery 5 stores the energy generated by the motor generator 82. A positive electrode 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, a negative electrode 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 and closing of SMRs 43 and 44 is controlled by a command from ECU 10.

[0017] Cooling device 7, for example, is a liquid-cooled cooling device that uses a liquid refrigerant. Cooling device 7 cools battery 5 according to a command from ECU 10.

[0018] The PCU 81 is electrically connected between the power lines PL2, NL2 and the motor-generator 82. The PCU 81 includes a converter and an inverter (neither of which are shown) and drives the motor-generator 82 according to a command from the ECU 10.

[0019] The motor-generator 82 is a rotating AC electric machine, for example, a permanent magnet synchronous motor with a rotor in which a permanent magnet is embedded. The output torque of the motor-generator 82 is transmitted via the power transmission gearbox 83 to the drive wheels 84 and sets the vehicle 1 in motion. Furthermore, the motor-generator 82 can generate electricity when the vehicle 1 decelerates due to the rotational force of the drive wheels 84. The energy generated by the motor-generator 82 is converted by the PCU 81 into charging energy for the battery 5.

[0020] The ECU 10 comprises a processor 11, such as a central processing unit (CPU), memory 12, such as read-only memory (ROM) and working memory (RAM), and an input / output connector 13. The ECU 10 controls the devices according to the signals from the various sensors, etc., to bring the vehicle 1 into a desired state. The ECU 10 can be divided into several ECUs for corresponding functions (e.g., a battery ECU, a motor generator (MG) ECU, etc.).

[0021] The SOC sensor 61 detects the state of charge (SOC) of battery 5. The SOC sensor 61 can directly detect the SOC of battery 5. The SOC sensor can detect the voltage VB of battery 5 and the current IB supplied to or drawn from battery 5, and determine the SOC of battery 5 based on the voltage VB and the current IB.

[0022] 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 supplied to or drawn from the battery 5 and determine the ambient temperature TA of the battery 5 based on the current IB.

[0023] The load sensor 62 detects a holding load FA of the battery 5. For example, the load sensor 62 can be clamped between the cells 50 of the battery 5 to detect the holding load FA of the battery 5.

[0024] The battery temperature sensor 64 detects a temperature TB of the battery 5. The battery temperature sensor 64 operates intermittently.

[0025] The Fig. 2A, Fig. 2B and Fig. 2C each show an example of the risk of smoke development from battery 5. As it occurs in Fig. As shown in 2A, the risk of smoke development from battery 5 increases as the state of charge (SOC) of battery 5 increases. As shown in Fig. As shown in Figure 2B, the risk of smoke development from battery 5 increases when the ambient temperature TA of battery 5 increases. As shown in Figure 2B, the risk of smoke development from battery 5 increases when the ambient temperature TA of battery 5 increases. Fig. As shown in Figure 2C, the risk of smoke development from battery 5 increases when the retention load FA of battery 5 is higher.

[0026] Fig. Figure 3 shows an example of checking the temperature TB of battery 5.

[0027] If the risk of smoke emanating from the battery increases, it is necessary to shorten the interval in which the temperature TB of battery 5 is checked.

[0028] In the present embodiment, the cycle in which the battery temperature sensor 64 is operated to detect the temperature TB of the battery 5 is determined on the basis of the above considerations.

[0029] The ECU 10 determines the operating cycle of the battery temperature sensor 64 based on the state of charge (SOC) of battery 5, the ambient temperature (TA) of battery 5, and the retaining load (FA) of battery 5. The ECU 10 operates the battery temperature sensor 64 within the determined operating cycle. The cooling device 7 is controlled based on the temperature (TB) of battery 5 detected by the battery temperature sensor 64.

[0030] The ECU 10 calculates a variable α based on the SOC of battery 5, calculates a variable β based on the ambient temperature TA of battery 5, and calculates a variable γ based on the retaining load FA of battery 5, and increases the operating cycle of the battery temperature sensor 64 when the sum of the variables α, β, and γ is greater.

[0031] The ECU 10 sets the variable α to a first value when the SOC of battery 5 is in a first range, sets the variable α to a second value that is smaller than the first value when the SOC of battery 5 is in a second range that is larger than the first range, and sets the variable α to a third value that is smaller than the second value when the SOC of battery 5 is in a third range that is larger than the second range.The ECU 10 sets the variable β to a first value when the ambient temperature TA of battery 5 is in a first range, sets the variable β to a second value that is smaller than the first value when the ambient temperature TA of battery 5 is in a second range that is larger than the first range, and sets the variable β to a third value that is smaller than the second value when the ambient temperature TA of battery 5 is in a third range that is larger than the second range.

[0032] The ECU 10 sets the variable γ to a first value when the retention load FA of battery 5 is in a first range, sets the variable γ to a second value that is smaller than the first value when the retention load FA of battery 5 is in a second range that is larger than the first range, and sets the variable γ to a third value that is smaller than the second value when the retention load FA of battery 5 is in a third range that is larger than the second range.

[0033] Fig. Figure 4 is a flowchart illustrating the procedure for controlling the monitoring of battery 5.

[0034] In step S101, the ECU 10 detects the SOC of battery 5 as determined by the SOC sensor 61. If the SOC of battery 5 is 0% to 30%, the process continues with step S102; if the SOC of battery 5 is 31% to 70%, the process continues with step S103; and if the SOC of battery 5 is 71% to 100%, the process continues with step S104.

[0035] In step S102, ECU 10 sets the variable α to 2. In step S103, ECU 10 sets the variable α to 1.

[0036] In step S104, the ECU 10 sets the variable α to 0. In step S105, the ECU 10 detects the ambient temperature TA of battery 5 as determined by the ambient temperature sensor 63. If the ambient temperature TA of battery 5 is between 0°C and 20°C, the process continues with step S106; if the ambient temperature TA of battery 5 is between 21°C and 30°C, the process continues with step S107; and if the ambient temperature TA of battery 5 is 31°C or higher, the process continues with step S108.

[0037] In step S106, ECU 10 sets the variable β to 2. In step S107, ECU 10 sets the variable β to 1.

[0038] In step S108, the ECU 10 sets the variable β to 0. In step S109, the ECU 10 detects the holding load FA of battery 5 as determined by the load sensor 62. If the holding load FA of battery 5 is 1.9 kN or less, the process continues with step S110; if the holding load FA of battery 5 is 2.0 kN to 3.9 kN, the process continues with step S111; and if the holding load FA of battery 5 is 4.0 kN or more, the process continues with step S112.

[0039] In step S110, ECU 10 sets the variable γ to 2. In step S111, ECU 10 sets the variable γ to 1.

[0040] In step S112, the ECU 10 sets the variable γ to 0. In step S113, the ECU 10 determines the operating interval (activity interval) f [s] of the battery temperature sensor 64 using the following equation (1). f=30+10×(α+β+γ)

[0041] As described above, according to the present embodiment, the operating cycle of the battery temperature sensor is determined based on the battery's state of charge (SOC), the battery's ambient temperature, and the battery's holding load, making it possible to reduce the risk of smoke generation with high accuracy and to reduce power consumption.

[0042] Instead of the ambient temperature of battery 5, the outside air temperature can also be used.

[0043] The embodiment disclosed herein should in every respect be regarded as exemplary and not as limiting. The scope of this disclosure is defined by the claims and not by the above description and is intended to include all modifications that fall within the meaning and scope of those of the claims. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 2021-036485 [0002, 0003]

Claims

Battery monitoring device comprising: a state of charge (SOC) sensor for detecting the SOC of a battery; an ambient temperature sensor for detecting the ambient temperature of the battery; a load sensor for detecting a retaining load of the battery; a battery temperature sensor for detecting the temperature of the battery; and a control device that determines an operating cycle of the battery temperature sensor based on the SOC, the ambient temperature, and the retaining load, and operates the battery temperature sensor in the determined operating cycle. Battery monitoring device according to claim 1, wherein the control device calculates a first variable based on the SOC, calculates a second variable based on the ambient temperature, calculates a third variable based on the retention load, and increases the operating cycle as the sum of the first variable, the second variable, and the third variable. Battery monitoring device according to claim 2, wherein the control device sets the first variable to a first value when the SOC is in a first range, sets the first variable to a second value that is less than the first value when the SOC is in a second range that is greater than the first range, and sets the first variable to a third value that is less than the second value when the SOC is in a third range that is greater than the second range. Battery monitoring device according to claim 2, wherein the control device sets the second variable to a first value when the ambient temperature is in a first range, sets the second variable to a second value that is less than the first value when the ambient temperature is in a second range that is greater than the first range, and sets the second variable to a third value that is less than the second value when the ambient temperature is in a third range that is greater than the second range. Battery monitoring device according to claim 2, wherein the control device sets the third variable to a first value when the retaining load is in a first range, sets the third variable to a second value that is less than the first value when the retaining load is in a second range that is greater than the first range, and sets the third variable to a third value that is less than the second value when the retaining load is in a third range that is greater than the second range.

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