Battery monitoring device

Abstract

To provide a battery monitoring device that can detect the battery temperature at the appropriate time. [Solution] The battery monitoring device 200 includes an SOC sensor 61 for detecting the state of charge (SOC) of the battery 5, an ambient temperature sensor 63 for detecting the ambient temperature of the battery 5, a load sensor 62 for detecting the constraint load of the battery 5, a battery temperature sensor 64 for detecting the temperature of the battery 5, and an ECU 10 that determines the operating cycle of the battery temperature sensor 64 based on the SOC, ambient temperature, and constraint load, and operates the battery temperature sensor 64 at the determined operating cycle.

Description

Technical Field

[0001] The present disclosure relates to a battery monitoring device.

Background Art

[0002] The cooling method of the power supply device described in Patent Document 1 includes a step of detecting the SOC of the battery and the ambient temperature, a step of determining whether or not it meets a predetermined temperature evaluation criterion based on the detected SOC and temperature, and a step of operating a cooling mechanism for cooling the battery when it is determined that it does not meet the temperature evaluation criterion.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The cooling method described in Patent Document 1 uses only the SOC of the battery and the ambient temperature for temperature evaluation, and there is room for improvement in terms of accuracy improvement.

[0005] There are problems that the risk of smoke generation increases when the interval for detecting the temperature of the battery is long, and the power consumption increases when the interval for detecting the temperature of the battery is long.

[0006] An object of the present disclosure is to provide a battery monitoring device capable of detecting the temperature of a battery at an appropriate timing.

Means for Solving the Problems

[0007] The battery monitoring device of this disclosure includes an SOC sensor for detecting the state of charge (SOC) of a battery, an ambient temperature sensor for detecting the ambient temperature of a battery, a load sensor for detecting the constraint load on a battery, a battery temperature sensor for detecting the temperature of a battery, and a control device for determining the operating cycle of the battery temperature sensor based on the SOC, ambient temperature, and constraint load, and for operating the battery temperature sensor at the determined operating cycle. [Effects of the Invention]

[0008] According to this disclosure, the battery temperature can be detected at an appropriate time. [Brief explanation of the drawing]

[0009] [Figure 1] This diagram schematically shows the overall configuration of a vehicle equipped with a battery cooling device according to an embodiment. [Figure 2] (a) to (c) are diagrams illustrating an example of the smoke emission risk of battery 5. [Figure 3] This diagram illustrates an example of checking the temperature TB of battery 5. [Figure 4] This is a flowchart illustrating the procedure for monitoring and controlling battery 5. [Modes for carrying out the invention]

[0010] The embodiments will be described below with reference to the drawings. Figure 1 is a schematic diagram showing the overall configuration of a vehicle equipped with a battery cooling device according to an embodiment. Vehicle 1 is, for example, an electric vehicle. Vehicle 1 is configured to enable external charging (so-called plug-in charging), which involves supplying power to Vehicle 1 from a charger (not shown) to charge the on-board battery 5. It is not essential that Vehicle 1 is configured to enable external charging. Vehicle 1 may be a regular hybrid vehicle that does not support external charging.

[0011] 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 (SMR) 43, 44, power lines PL2, NL2, a battery 5, a SOC sensor 61, an ambient temperature sensor 63, a load sensor 62, a battery temperature sensor 64, a cooling device 7, a PCU (Power Control Unit) 81, a motor generator 82, a power transmission gear 83, drive wheels 84, and an ECU (Electronic Control Unit) 10.

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

[0013] The inlet (charging port) 2 is configured to allow insertion of a charging cable connector (not shown) with mechanical connection such as mating.

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

[0015] The charging relay 41 is connected to the charging line PL1, and the charging relay 42 is connected to the charging line NL1. The closing / opening of the charging relays 41 and 42 is controlled according to commands from the ECU 10. When the charging relays 41 and 42 are closed, and the SMRs 43 and 44 are also closed, power transmission between the inlet 2 and the battery 5 becomes possible.

[0016] The battery 5 is a battery pack including a plurality of cells 50. Each cell 50 is a lithium-ion secondary battery. The battery 5 supplies power for generating the driving force of the vehicle 1. Also, the battery 5 stores the power generated by the motor generator 82. The positive electrode of the battery 5 is electrically connected to the node ND1 via the SMR43. The node ND1 is electrically connected to the charging line PL1 and the power line PL2. Similarly, the negative electrode of the battery 5 is electrically connected to the node ND2 via the SMR44. The node ND2 is electrically connected to the charging line NL1 and the power line NL2. The closing / opening of the SMRs 43 and 44 is controlled according to a command from the ECU10.

[0017] The cooling device 7 is, for example, a liquid-cooled cooling device using a liquid refrigerant. The cooling device 7 cools the battery 5 according to a command from the ECU10.

[0018] The PCU 81 is electrically connected between the power lines PL2 and NL2 and the motor generator 82. The PCU 81 includes a converter and an inverter (both not shown) and drives the motor generator 82 according to a command from the ECU10.

[0019] The motor generator 82 is an AC rotating electric machine, for example, a permanent magnet type synchronous motor having a rotor in which permanent magnets are embedded. The output torque of the motor generator 82 is transmitted to the drive wheels 84 through the power transmission gear 83 to drive the vehicle 1. Also, the motor generator 82 can generate electricity by the rotational force of the drive wheels 84 during the braking operation of the vehicle 1. The generated power by the motor generator 82 is converted into the charging power of the battery 5 by the PCU 81.

[0020] The ECU 10 includes a processor 11 such as a CPU (Central Processing Unit), a memory 12 such as a ROM (Read Only Memory) and a RAM (Random Access Memory), and an input / output port 13. The ECU 10 controls devices so that the vehicle 1 is in a desired state according to signals from each sensor and the like. The ECU 10 may be configured by being divided into a plurality of ECUs (for example, an ECU for a battery, an ECU for an MG, etc.) for each function.

[0021] The SOC sensor 61 detects the SOC of the battery 5. The SOC sensor 61 may directly detect the SOC of the battery 5. The SOC sensor may detect the voltage VB of the battery 5 and the current IB input to and output from the battery 5, and detect the SOC of the 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 may directly detect the ambient temperature TA of the battery 5. The ambient temperature sensor 63 may 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.

[0023] The load sensor 62 detects the restraint load FA of the battery 5. For example, the load sensor 62 may be sandwiched between the cells 50 of the battery 5 to detect the restraint load FA of the battery 5.

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

[0025] Figs. 2(a) to (c) are diagrams for explaining an example of the smoke risk of the battery 5. As shown in Fig. 2(a), as the SOC of the battery 5 increases, the smoke risk of the battery 5 increases. As shown in Fig. 2(b), as the ambient temperature TA of the battery 5 increases, the smoke risk of the battery 5 increases. As shown in Fig. 2(c), as the restraint load FA of the battery 5 increases, the smoke risk of the battery 5 increases.

[0026] Figure 3 illustrates an example of checking the temperature TB of battery 5. If the risk of battery smoke increases, the interval for checking the temperature TB of battery 5 needs to be shortened.

[0027] In this embodiment, based on the above considerations, the period for activating the battery temperature sensor 64 to detect the temperature TB of the battery 5 is determined.

[0028] The ECU 10 determines the operating cycle of the battery temperature sensor 64 based on the state of charge (SOC) of the battery 5, the ambient temperature (TA) of the battery 5, and the constraint load (FA) of the battery 5. The ECU 10 activates the battery temperature sensor 64 at the determined operating cycle. The cooling device 7 is controlled based on the temperature (TB) of the battery 5 detected by the battery temperature sensor 64.

[0029] The ECU 10 determines variable α based on the state of charge (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 larger the sum of variables α, β, and γ, the longer the operating period of the battery temperature sensor 64.

[0030] The ECU 10 sets variable α to a first value when the State of Charge (SOC) of battery 5 is within a first range, sets variable α to a second value smaller than the first value when the SOC of battery 5 is within a second range greater than the first range, and sets variable α to a third value smaller than the second value when the SOC of battery 5 is within a third range greater than the second range. The ECU 10 sets the variable β to a first value when the ambient temperature TA of the battery 5 is within a first range, sets the variable β to a second value smaller than the first value when the ambient temperature TA of the battery 5 is within a second range greater than the first range, and sets the variable β to a third value smaller than the second value when the ambient temperature TA of the battery 5 is within a third range greater than the second range.

[0031] The ECU 10 sets the variable γ to a first value when the constraint load FA of the battery 5 is within a first range, sets the variable γ to a second value smaller than the first value when the constraint load FA of the battery 5 is within a second range greater than the first range, and sets the variable γ to a third value smaller than the second value when the constraint load FA of the battery 5 is within a third range greater than the second range.

[0032] Figure 4 is a flowchart illustrating the procedure for monitoring and controlling battery 5. In step S101, the ECU 10 obtains the State of Charge (SOC) of the battery 5 detected by the SOC sensor 61. If the SOC of the battery 5 is 0-30%, the process proceeds to step S102; if the SOC of the battery 5 is 31-70%, the process proceeds to step S103; and if the SOC of the battery 5 is 71-100%, the process proceeds to step S104.

[0033] In step S102, the ECU10 sets the variable α to 2. In step S103, the ECU10 sets the variable α to 1.

[0034] In step S104, the ECU10 sets the variable α to 0. In step S105, the ECU 10 obtains the ambient temperature TA of the battery 5 detected by the ambient temperature sensor 63. If the ambient temperature TA of the battery 5 is 0 to 20°C, the process proceeds to step S106; if the ambient temperature TA of the battery 5 is 21 to 30°C, the process proceeds to step S107; and if the ambient temperature TA of the battery 5 is 31°C or higher, the process proceeds to step S108.

[0035] In step S106, the ECU10 sets the variable β to 2. In step S107, the ECU10 sets the variable β to 1.

[0036] In step S108, the ECU10 sets the variable β to 0. In step S109, the ECU 10 obtains the constrained load FA of the battery 5 detected by the load sensor 62. If the constrained load FA of the battery 5 is 1.9kN or less, the process proceeds to step S110; if the constrained load FA of the battery 5 is between 2.0 and 3.9kN, the process proceeds to step S111; and if the constrained load FA of the battery 5 is 4.0kN or more, the process proceeds to step S112.

[0037] In step S110, ECU10 sets the variable γ to 2. In step S111, the ECU10 sets the variable γ to 1.

[0038] In step S112, the ECU10 sets the variable γ to 0. In step S113, the ECU 10 determines the operating interval (startup interval) f[s] of the battery temperature sensor 64 by the following equation (1).

[0039] 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 state of charge (SOC), the ambient temperature of the battery, and the battery's restraining load, thereby reducing the risk of smoke emission with high accuracy and reducing power consumption.

[0040] Alternatively, ambient temperature may be used instead of the ambient temperature for battery 5. The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of this disclosure is indicated by the claims rather than the foregoing description, and all modifications within the meaning and scope equivalent to the claims are intended. [Explanation of Symbols]

[0041] 1 Vehicle, 2 Inlet, 5 Battery, 7 Cooling device, 11 Processor, 12 Memory, 13 Input / Output port, 31 Voltage sensor, 32 Current sensor, 41, 42 Charging relay, 50 Cell, 61 SOC sensor, 62 Load sensor, 63 Ambient temperature sensor, 64 Battery temperature sensor, 82 Motor generator, 83 Power transmission gear, 84 Drive wheel, 200 Battery monitoring device, NL1, PL1 Charging line, NL2, PL2 Power line.

Claims

1. An SOC sensor that detects the battery's SOC, An ambient temperature sensor for detecting the ambient temperature of the aforementioned battery, A load sensor for detecting the restraining load of the battery, A battery temperature sensor that detects the temperature of the battery, A battery monitoring device comprising: a control device that determines the operating cycle of the battery temperature sensor based on the SOC, the ambient temperature, and the restraining load, and operates the battery temperature sensor at the determined operating cycle.

2. The battery monitoring device according to claim 1, wherein the control device determines a first variable based on the SOC, a second variable based on the ambient temperature, 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 the control device sets the first variable to a first value when the SOC is within a first range, sets the first variable to a second value smaller than the first value when the SOC is within a second range greater than the first range, and sets the first variable to a third value smaller than the second value when the SOC is within a third range greater than the second range.

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

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

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