Fan driving method

Abstract

The present invention addresses the problem of driving a fan disposed in a battery pack without affecting drivability and without causing an increase in the volume of an ECU. A fan driving method in which a cooler temperature, which is the temperature of a cooler for cooling a battery cell group provided in a battery pack, and a high-temperature part temperature, which is the temperature of a high-temperature part different from the battery cell group, are obtained from a thermoelectric element that detects the cooler temperature and the high-temperature part temperature, and the fan is driven on the basis of the temperature difference. A fan arranged in the battery pack is started, and the air volume of the fan is adjusted according to the temperature difference.

Description

Technical Field

[0001] This invention relates to a fan driving method. Background Technology

[0002] The battery pack described in Patent Document 1 below houses multiple individual batteries within a sealed internal space, enabling effective cooling of the housed individual batteries. To address this issue, an insertion hole is formed in the housing, connecting the internal space and an external space outside the housing. A rotating shaft of a motor is inserted through this insertion hole. The motor drives an internal fan located within the housing's internal space, thus circulating air within the internal space to cool each individual battery. Furthermore, since the rotating shaft is inserted through the insertion hole, an external fan can be mounted on the rotating shaft protruding outward from the housing. Therefore, by using a single motor, fans are mounted not only inside but also outside the housing, allowing cooling from the outside of the housing.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2014-229560 Summary of the Invention In Patent Document 1, power for driving the fan must be drawn from the electricity used to drive the vehicle each time. Therefore, driving performance is affected by driving the fan. A temperature sensor is required for fan control, increasing the cost of adding such a sensor. The control logic for turning the fan on and off needs to be integrated into the ECU (Electronic Control Unit), thus complicating the ECU's control circuitry. This addition of functionality increases the size of the ECU board, and sometimes additional connectors are needed to connect the fan and the ECU, further increasing the overall size of the ECU.

[0004] The purpose of this invention is to drive a fan located within the battery pack without affecting driving performance or increasing the size of the ECU.

[0005] The fan driving method of the present invention includes detecting the temperature of the cooler that cools the battery cell group disposed in the battery pack, i.e., the cooler temperature, and obtaining the temperature difference between the cooler temperature and the high temperature part temperature by a thermoelectric element that detects the temperature of a high temperature part that is different from the battery cell group, i.e., the high temperature part temperature; and starting a fan disposed in the battery pack according to the temperature difference, and adjusting the air volume of the fan according to the temperature difference.

[0006] Invention Effects According to the present invention, a fan configured within the battery pack can be driven without affecting driving performance and without increasing the size of the ECU. Attached Figure Description

[0007] Figure 1This is a schematic structural diagram showing the structure of the battery pack involved in this embodiment.

[0008] Figure 2 This is a schematic structural diagram showing the structure of the battery pack involved in the modified example.

[0009] Figure 3 This is a schematic structural diagram showing the structure of the battery pack involved in the modified example. Detailed Implementation

[0010] Hereinafter, this embodiment will be described with reference to the accompanying drawings. To facilitate understanding, identical components in each figure will be labeled with the same symbols as much as possible, and repeated descriptions will be omitted.

[0011] Figure 1 The battery pack P1 shown is installed in electric vehicles that require large battery packs, such as battery electric vehicles (BEVs) or plug-in hybrid electric vehicles (PHEVs). For example, in the case of a plug-in hybrid electric vehicle, the battery pack P1 becomes hot due to heat from the vehicle side (radiant heat from the exhaust pipe, hot air from the engine compartment). The battery pack P1 sometimes experiences internal thermal interference due to heat generated by internally installed equipment. For example, suppose the ambient temperature outside the battery pack P1 is approximately 90°C.

[0012] The battery pack P1 according to this embodiment includes a battery cell group 10, a cooler 11, a device 12, a fan 13, and a thermoelectric element 14. The battery cell group 10 is composed of multiple batteries. The cooler 11 is used to cool the battery cell group 10. In this embodiment, the temperature of the cooler 11 is approximately 20°C. The device 12 is a device installed in the battery pack P1. The fan 13 is a fan used to circulate air within the battery pack P1.

[0013] The thermoelectric element 14 is configured such that one side contacts the inner peripheral wall of the battery pack P1, and the other side contacts the cooler 11. The thermoelectric element 14 is a component that generates an electromotive force based on the Seebeck effect, where a temperature difference is created by heating one side and cooling the other. For example, if a 2cm × 2cm thermoelectric element 14 is used, a maximum of 2W of power can be obtained at a temperature difference of 70°C (ambient temperature 90°C - cooler temperature 20°C). The fan 13 requires 0.5W of power to drive, therefore the fan 13 can be driven by the thermoelectric element 14.

[0014] The electromotive force generated by thermoelectric element 14 increases as the temperature difference increases and decreases as the temperature difference decreases. Therefore, if the ambient temperature outside the battery pack P1 increases, the temperature difference increases, and thus the electromotive force generated by thermoelectric element 14 increases, increasing the power supply to fan 13, and the fan 13 rotates faster, thereby increasing the airflow.

[0015] like Figure 2 As shown, the modified example of battery pack P2 includes a device 15 with high heat generation, in addition to device 12. Battery pack P2 includes battery cell group 10, cooler 11, device 12, fan 13, device 15, and thermoelectric element 16. When battery pack P2 is installed, for example, in a BEV, since there is no heat exhaust from the engine, the ambient temperature will not increase, but the heat generated by device 15 needs to be addressed.

[0016] The heating temperature of device 15 is, for example, 110°C. Thermoelectric element 16 is configured such that one side contacts device 15 and the other side contacts cooler 11. Thermoelectric element 16 is a component that generates an electromotive force through the Seebeck effect, when a temperature difference is created by heating one side and cooling the other side.

[0017] like Figure 3 As shown, the modified battery pack P3 is a combination of the structures of battery pack P1 and battery pack P2. Battery pack P3 includes battery cell group 10, cooler 11, device 12, fan 13, thermoelectric element 14, device 15, and thermoelectric element 16.

[0018] Thermoelectric element 14 is configured such that one side contacts the inner peripheral wall of battery pack P1, and the other side contacts the cooler 11. Thermoelectric element 16 is configured such that one side contacts device 15, and the other side contacts cooler 11. With this configuration, fan 13 is driven by the electromotive force generated by thermoelectric elements 14 and 16.

[0019] The above description of this embodiment is based on specific examples. However, the present invention is not limited to these specific examples. Those skilled in the art can make appropriate design changes to these specific examples, and as long as they possess the features of the present invention, they are also included within the scope of the present invention. The elements, their configurations, conditions, shapes, etc., of the aforementioned specific examples are not limited to the illustrated elements and can be appropriately modified. As long as no technical contradiction arises, the elements of the aforementioned specific examples can be appropriately combined and changed.

[0020] [Postscript] [Postscript 1] Thermoelectric elements 14 and 16 detect the temperature of the cooler 11 of the battery cell group 10 located in the battery packs P1, P2, and P3, i.e., the cooler temperature, and detect the temperature of the high-temperature part that is different from the battery cell group 10, i.e., the high-temperature part temperature, to obtain the temperature difference between the cooler temperature and the high-temperature part temperature. Based on the temperature difference, the fan 13 located in the battery packs P1, P2, and P3 is started, and the airflow of the fan 13 is adjusted according to the temperature difference.

[0021] In the case of battery pack P1, for example, since it is installed in a plug-in hybrid electric vehicle, it becomes a high-temperature state due to heat from the vehicle side (radiant heat from the exhaust pipe, hot air from the engine compartment), so the high-temperature part becomes the outer periphery of battery pack P1. In the case of battery pack P2, for example, since it is installed in a BEV, there is no heat exhaust from the engine, so the external ambient temperature will not increase, but device 15 generates heat at a high temperature, so the high-temperature part becomes device 15. In the case of battery pack P3, the high-temperature part becomes both the outer periphery of battery pack P1 and device 15.

[0022] According to Appendix 1, thermoelectric elements 14 and 16 acquire the temperature difference between the cooler temperature and the high-temperature part temperature. Based on this temperature difference, fans 13 located in battery packs P1, P2, and P3 are activated. The airflow of fans 13 is adjusted according to the temperature difference. Therefore, there is no need for an ECU to drive and control fans 13, and no need to integrate the control logic for drive control into the ECU. Power for driving fans 13 does not need to be drawn from the power used to drive the vehicle. Driving performance is not affected by driving fans 13. A temperature sensor is also not required for fan control.

[0023] Symbol Explanation P1, P2, P3 - Battery pack, 10 - Battery cell group, 11 - Cooler, 12 - Equipment, 13 - Fan, 14 - Thermoelectric element, 15 - Equipment, 16 - Thermoelectric element.

Claims

1. A fan driving method, characterized in that, A thermoelectric element detects the temperature of the cooler (i.e., the cooler temperature) of the battery cell assembly within the battery pack, and detects the temperature of the high-temperature portion (i.e., the high-temperature part temperature) that differs from the battery cell assembly. This temperature difference between the cooler temperature and the high-temperature part temperature is then determined. Based on the temperature difference, the fan located in the battery pack is activated. The fan speed is adjusted according to the temperature difference.

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