Gas generation detection device for battery pack

Abstract

To provide a gas generation detection device for a battery pack in which erroneous detection of gas generation is suppressed.SOLUTION: A gas generation detection device of a battery pack including a case housing a battery, a sensor for detecting a pressure in the case, and an opening valve for opening the pressure in the case to the outside when the pressure is equal to or greater than a threshold is a gas generation detection device of the battery pack, comprising: a first determination part configured to determine whether the pressure is equal to or greater than the threshold based on a detection value of the sensor; a second determination part for determining whether the pressure rises after closing the opening valve based on the detection value of the sensor in the case of a positive determination by the first determination part; and a detection part for detecting generation of gas in the battery pack in the case of a positive determination by the second determination part.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a gas generation detection device for a battery pack. [Background technology]

[0002] There is a technique for detecting the generation of gas inside a battery pack based on the detection value of a pressure sensor (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2022-516910 Summary of the Invention [Problem to be solved by the invention]

[0004] When detecting gas generation using the above-mentioned pressure sensor, the detected value of the pressure sensor may fluctuate due to external forces or vibrations applied to the battery pack, or thermal expansion of the batteries inside the battery pack. With the above-mentioned technology, the detected value of the pressure sensor may fluctuate due to such causes, and there is a risk that the generation of gas may be erroneously detected.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a gas generation detection device for a battery pack that suppresses false detection of gas generation. [Means for solving the problem]

[0006] The above object can be achieved by a gas generation detection device for a battery pack having a case that houses a battery, a sensor that detects the pressure inside the case, and an open valve that releases the pressure inside the case to the outside when the pressure is equal to or greater than a threshold value, the gas generation detection device for a battery pack comprising: a first determination unit that determines whether the pressure has reached or exceeded the threshold value based on the detection value of the sensor; a second determination unit that, if the first determination unit makes a positive determination, determines whether the pressure has increased after the open valve is closed based on the detection value of the sensor; and a detection unit that detects gas generation inside the battery pack if the second determination unit makes a positive determination. [Effects of the Invention]

[0007] It is possible to provide a gas generation detection device for a battery pack that suppresses false detection of gas generation. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is a schematic diagram of a battery pack. [Figure 2] 10 is a flowchart illustrating a gas generation detection control of a battery pack. [Figure 3] 10 is a timing chart illustrating an example of gas generation detection control in a battery pack. DETAILED DESCRIPTION OF THE INVENTION

[0009] [Battery pack configuration] 1 is a schematic diagram of a battery pack 1. The battery pack 1 is mounted on a vehicle such as an electric vehicle, a hybrid vehicle, or a fuel cell vehicle. The battery pack 1 has a case 10, an open valve 12, a battery 20, a voltage monitoring device 30, and a battery ECU (Electronic Control Unit) 40. The battery 20, the voltage monitoring device 30, and the battery ECU 40 are housed in the case 10.

[0010] The battery 20 is an assembled battery including multiple battery cells. Each cell is a secondary battery such as a lithium-ion battery. When the battery pack 1 is mounted on a vehicle, the battery 20 supplies power to, for example, a motor that powers the vehicle. The voltage monitoring device 30 monitors the voltage of the battery 20. The battery ECU 40 is composed of a CPU (Central Processing Unit), ROM (Read Only Memory), and RAM (Random Access Memory). The battery ECU 40 is provided with a pressure sensor 44. The pressure sensor 44 detects the pressure inside the case 10. The pressure sensor 44 may also be provided in the voltage monitoring device 30. The battery ECU 40 manages the state of charge of the battery 20 based on input signals from the voltage monitoring device 30 and the pressure sensor 44, as well as maps and programs stored in the memory 22. The battery ECU 40 is an example of a gas generation detection device for the battery pack 1, and functionally implements a first determination unit, a second determination unit, and a detection unit.

[0011] The release valve 12 is attached to the opening of the case 10. The release valve 12 is maintained in a closed state by a spring (not shown). When the pressure inside the case 10 exceeds a predetermined threshold, the release valve 12 opens against the biasing force of the spring. When the release valve 12 opens, the pressure inside the case 10 is released to the outside. As a result, the pressure inside the case 10 drops significantly from the threshold. When the pressure inside the case 10 drops to a predetermined value, the release valve 12 closes again in accordance with the biasing force of the spring. In this way, the release valve 12 prevents the pressure inside the case 10 from becoming excessive.

[0012] [Gas generation detection control for battery packs] 2 is a flowchart illustrating gas generation detection control for a battery pack. The battery ECU 40 determines whether the pressure inside the case 10 is equal to or greater than the threshold value described above (step S1). If the result in step S1 is No, this control ends. Step S1 is an example of processing executed by the first determination unit. If the result in step S1 is Yes, the release valve 12 is considered to be open, and the battery ECU 40 determines whether a predetermined time has elapsed since the result in step S1 was Yes (step S2). The predetermined time is set to the time from when the release valve 12 opens until the release valve 12 closes due to a drop in pressure inside the case 10. If the result in step S2 is No, step S2 is executed again.

[0013] If the answer is Yes in step S2, the release valve 12 is considered to be closed, and the battery ECU 40 determines whether the pressure inside the case 10 is rising (step S3). In detail, if the rate of increase in the pressure inside the case 10 per unit time after the answer is Yes in step S2 is equal to or greater than a predetermined value, it is determined that the pressure inside the case 10 is rising. If the answer is No in step S3, this control ends. Step S3 is an example of processing executed by the second determination unit.

[0014] If the answer is Yes in step S3, the battery ECU 40 detects the generation of gas in the battery pack 1 (step S4). Step S4 is an example of processing executed by the detection unit. As described above, when the pressure inside the case 10 exceeds the threshold and the pressure inside the case 10 continues to rise thereafter, the generation of gas in the battery pack 1 is detected. Therefore, even if the pressure inside the case 10 temporarily rises due to, for example, thermal expansion of the battery 20 or an external force, the generation of gas will not be detected if the pressure does not rise thereafter. Therefore, false detection of gas generation in the battery pack 1 is suppressed, and gas generation is detected with high accuracy.

[0015] Furthermore, when the battery ECU 40 detects the generation of gas within the battery pack 1, the battery ECU 40 may issue an instruction to, for example, an external ECU installed in the vehicle, to cool the battery pack 1 with coolant or to turn on the MIL (Malfunction Indicator Light).

[0016] Fig. 3 is a timing chart illustrating gas generation detection control for a battery pack. Fig. 3 shows the transition of pressure inside the case 10. When the pressure inside the case 10 reaches or exceeds the threshold value (time t1), the release valve 12 opens and the pressure inside the case 10 decreases. When the release valve 12 subsequently closes (time t2), the pressure inside the case 10 gradually increases. When it is determined that the pressure inside the case 10 is increasing (time t3), gas generation inside the battery pack 1 is detected.

[0017] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and variations are possible within the scope of the gist of the present invention as defined in the claims. [Explanation of symbols]

[0018] 1 battery pack 10 cases 12 Release valve 20 batteries 40 Battery ECU (first determination unit, second determination unit, detection unit) 44 Pressure Sensor

Claims

[Claim 1] A gas generation detection device for a battery pack, the device having a case that houses a battery, a sensor that detects pressure inside the case, and a release valve that releases the pressure inside the case to the outside when the pressure is equal to or greater than a threshold value, a first determination unit that determines whether the pressure is equal to or greater than the threshold value based on the detection value of the sensor; a second determination unit that determines, when the first determination unit makes a positive determination, whether the pressure has increased after the open valve is closed based on the detection value of the sensor; and a detection unit that detects gas generation in the battery pack when the second determination unit makes a positive determination.

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