Vehicle battery cooling structure and vehicle

Abstract

The present invention suitably adjusts the temperatures of a fixed battery and a replaceable battery to maintain battery performance.　This vehicle battery cooling structure comprises a cooling part that cools a battery in a fixed battery unit having a fixed battery and / or a replaceable battery unit having a replaceable battery, and a control part that controls the cooling part. The cooling part is provided with a heat exchanger, and also provided with cooling flow passages for flowing a heat medium, namely a first cooling flow passage for flowing a heat medium into the fixed battery unit through the heat exchanger, a second cooling flow passage for flowing a heat medium into the replaceable battery unit through the heat exchanger, and a third cooling flow passage for flowing a heat medium to the fixed battery unit and the replaceable battery unit through the heat exchanger, such that switching among the cooling flow passages is settable by opening / closing valves. When there is at least one battery which has a temperature beyond an appropriate temperature range, the control part performs opening / closing control of the valves such that one of the first, second, and third cooling flow passages is set on the basis of the temperature.

Description

Cooling Structure for Vehicle Battery and Vehicle

[0001] The present invention relates to a cooling structure for a vehicle battery and a vehicle.

[0002] Conventionally, as a vehicle equipped with a battery as a power source, in addition to a fixed battery (non-replaceable built-in battery) fixedly provided in the vehicle in advance, there is a vehicle equipped with a replaceable battery provided in the vehicle replaceably (see, for example, Patent Document 1).

[0003] Japanese Unexamined Patent Application Publication No. 2020-43718

[0004] In a vehicle equipped with such a fixed battery and a replaceable battery, the size of the replaceable battery is often smaller than that of the fixed battery. In such a case, when the power consumption (discharge amount) of the replaceable battery becomes relatively large, due to the relatively small surface area for heat dissipation, heat is likely to be trapped and the temperature is likely to rise. Also, in the fixed battery, the temperature may rise significantly, for example, when some load is applied. When the temperature of the battery rises in the vehicle and thereby temperature variations occur between the batteries, it becomes difficult to maintain the battery performance. Therefore, even in a vehicle equipped with such a fixed battery and a replaceable battery, it is required to appropriately cool the battery.

[0005] The present invention has been proposed to address such circumstances, and an object thereof is to provide a cooling structure for a vehicle battery capable of appropriately adjusting the temperatures of a fixed battery and a replaceable battery mounted in a vehicle and maintaining the battery performance, and a vehicle equipped with the cooling structure.

[0006] The present invention relates to a cooling structure for a vehicle battery that cools at least one of a fixed battery permanently installed in a vehicle and a replaceable battery that is replaceable in a vehicle, comprising: a fixed battery unit having the fixed battery; a replaceable battery unit having the replaceable battery; a cooling section that cools at least one of the fixed battery and the replaceable battery; and a control unit that controls the cooling section, wherein the cooling section comprises a heat exchanger and a cooling channel through which a heat transfer medium flows, a first cooling channel that flows the heat transfer medium to the fixed battery unit via the heat exchanger, and the heat exchanger The device is equipped with a second cooling channel through which a heat transfer medium flows to the replacement battery unit, and a third cooling channel through which a heat transfer medium flows to the fixed battery unit and the replacement battery unit via the heat exchanger, which can be switched and set by opening and closing a valve, and the control unit controls the opening and closing of the valve to set one of the first cooling channel, the second cooling channel, or the third cooling channel based on the temperatures of the fixed battery and the replacement battery, if at least one of the fixed battery and the replacement battery has a temperature exceeding the appropriate temperature range.

[0007] Furthermore, the present invention relates to a vehicle equipped with such a cooling structure for a vehicle battery.

[0008] According to the present invention, it is possible to provide a cooling structure for a vehicle battery that can appropriately regulate the temperature of a fixed battery and a replacement battery mounted in a vehicle and maintain battery performance, and a vehicle equipped with the cooling structure.

[0009] This is a schematic diagram illustrating the configuration of the battery cooling structure according to the first embodiment. This is a flowchart illustrating the operation process of the control unit in the battery cooling structure according to the first embodiment. This is a flowchart illustrating the operation process of the control unit in the battery cooling structure according to the second embodiment.

[0010] Embodiments of the present invention will be described with reference to the drawings. In the drawings of the first and second embodiments of the present invention described below, descriptions of identical components will be omitted.

[0011] [First Embodiment] First, a first embodiment of the present invention (hereinafter also simply referred to as "first embodiment") will be described. The vehicle battery cooling structure 1 according to the first embodiment (hereinafter also simply referred to as "battery cooling structure 1") will be described. As shown in Figure 1, the battery cooling structure 1 according to the first embodiment is a cooling structure that cools at least one of a fixed battery 21 and a replaceable battery 31 as a battery mounted on a vehicle 100.

[0012] Vehicle 100 is an electric vehicle (EV), which is an example of a vehicle that uses a battery as a power source. However, vehicle 100 is not limited to this, and may be any other vehicle that has a battery as a power source, such as a hybrid vehicle or a fuel cell vehicle.

[0013] The battery cooling structure 1 comprises a fixed battery unit 2 having a fixed battery 21, a replacement battery unit 3 having a replacement battery 31, a cooling unit 4 that cools at least one of the fixed battery 21 and the replacement battery 31, and a control unit 5 that controls the cooling unit 4.

[0014] The fixed battery unit 2 is constructed by housing a fixed battery 21 within a case 22. The case 22 is configured to enclose the entire fixed battery 21 and is permanently installed on the vehicle 100. Furthermore, the fixed battery 21 housed within the case 22 is fixed to the case 22. In other words, the fixed battery 21 is a battery (non-replaceable built-in battery) that is permanently installed in the vehicle 100. This fixed battery 21 is a high-voltage battery that stores power for driving.

[0015] The fixed battery (non-replaceable internal battery) 21 is, for example, a lithium-ion secondary battery, but is not limited to this and may be other secondary batteries, such as a nickel-metal hydride secondary battery. The fixed battery 21 has a plurality of battery cells (not shown) arranged in parallel with each other.

[0016] The stationary battery 21 is equipped with a sensor 6A that detects its temperature t and other state information of the stationary battery 21 (for example, total energy [Wh], SOC (State of Charge) [%], discharge capacity [mAh], voltage [V], etc.). As an example, the sensor 6A detects the highest temperature among the multiple battery cells in the stationary battery 21 as the temperature t of the stationary battery 21.

[0017] The replacement battery unit 3 is configured by detachably mounting a replacement battery 31 on a bucket 32. The bucket 32 ​​is fixedly installed on the vehicle 100. In other words, the replacement battery 31 is a battery that can be detachably replaced on the vehicle 100. This replacement battery 31 is a high-voltage battery that stores power for driving.

[0018] The replacement battery 31 is, for example, a lithium-ion secondary battery, but is not limited to this and may be other secondary batteries, such as a nickel-metal hydride secondary battery. The replacement battery 31 has a plurality of battery cells (not shown) arranged in parallel with each other and has a configuration equivalent to the fixed battery 21 described above, but its size is, for example, smaller than the fixed battery 21 described above, but is not limited to this and may be the same size as or larger than the fixed battery 21.

[0019] The replacement battery 31 is attached to and detached from the bucket 32 ​​by, for example, the user of the vehicle 100, or an employee of a highway service area or service station. The replacement battery 31 is available, for example, in a charged state at a highway service area or service station, and is loaded into the bucket 32 ​​in accordance with the request of the user of the vehicle 100.

[0020] The replacement battery 31 is equipped with a sensor 6B that detects its temperature t and other status information of the replacement battery 31 (for example, total energy [Wh], SOC (State of Charge) [%], discharge capacity [mAh], voltage [V], etc.). As an example, the sensor 6B detects the highest temperature among the multiple battery cells in the replacement battery 31 as the temperature t of the replacement battery 31.

[0021] When the control unit 5 receives temperature t data for the fixed battery 21 and temperature t data for the replacement battery 31 from sensors 6A and 6B via the bus 8, it controls the cooling unit 4 based on the temperature t data to cool the battery that requires cooling among the fixed battery 21 and the replacement battery 31.

[0022] The cooling unit 4 comprises a heat exchanger 41 and a cooling channel 43 formed in a pipe-like manner for flowing a heat transfer medium. The heat exchanger 41 is, for example, a radiator. The heat exchanger (radiator) 41 is positioned so that its front surface faces the front grille (not shown) and its rear surface faces the fixed battery unit 2 and the replacement battery unit 3. However, the orientation in which the heat exchanger 41 is positioned is not limited to this and may be changed as appropriate.

[0023] In the battery cooling structure 1, when cooling at least one battery, if the vehicle 100 is in motion, the battery is cooled using a heat transfer medium cooled by heat exchange with the outside air (airflow) introduced into the vehicle 100 from the front of the vehicle 100 through the front grille. At that time, the airflow introduced into the vehicle 100 is introduced into the heat exchanger (radiator) 41 from the front of the heat exchanger 41, passes through the core part (radiator core) of the heat exchanger 41, and exits to the outside of the heat exchanger 41 from the back of the heat exchanger 41. Here, in the core part of the heat exchanger 41, heat exchange takes place between the airflow and the heat transfer medium flowing through the cooling channel 43, and the heat transfer medium is cooled. Note that "in motion" means that the vehicle 100 is in the process of moving forward (in the direction of vehicle travel).

[0024] In addition, when cooling at least one of the batteries in the battery cooling structure 1, if it is impossible or difficult to obtain airflow while the vehicle 100 is stopped, a fan (not shown) may be rotated to introduce outside air into the heat exchanger (radiator) 41. In this case, heat exchange takes place in the core of the heat exchanger 41 between the introduced outside air and the heat transfer medium flowing through the cooling channel 43, thereby cooling the heat transfer medium.

[0025] Furthermore, the heat exchanger 41 may be a different type of heat exchanger than this radiator. For example, the heat exchanger 41 may be a chiller (e.g., a liquid-cooled chiller).

[0026] Furthermore, the cooling unit 4 includes a first cooling passage 43A, a second cooling passage 43B, and a third cooling passage 43C, which can be switched and set by opening and closing valves 42A (for fixed battery), 42B (for replacement battery), and 42C (for flow path connection valve).

[0027] The first cooling channel 43A is a channel through which a heat transfer medium flows to the fixed battery unit 2 via the heat exchanger 41. This first cooling channel 43A is formed by fully opening valve 42A (valve for fixed battery) and fully closing valve 42B (valve for replacement battery) and valve 42C (channel connection valve).

[0028] A portion of the first cooling channel 43A forms a meandering channel section. This meandering channel section of the first cooling channel 43A is provided, for example, on the bottom surface of the case 22 of the fixed battery unit 2. The heat transfer medium cooled by heat exchange in the heat exchanger 41 flows through this meandering channel section in the first cooling channel 43A, and heat exchange takes place between the heat transfer medium and the fixed battery 21, thereby cooling the fixed battery 21.

[0029] The second cooling channel 43B is a channel through which a heat transfer medium flows to the replacement battery unit 3 via the heat exchanger 41. This second cooling channel 43B is formed by fully opening valve 42B (valve for replacement battery) and fully closing valve 42A (valve for fixed battery) and valve 42C (channel connection valve).

[0030] A portion of the second cooling channel 43B forms a meandering channel section. This meandering channel section of the second cooling channel 43B is provided, for example, on the bottom surface of the bucket 32 ​​of the replacement battery unit 3. The heat transfer medium cooled by heat exchange in the heat exchanger 41 flows through this meandering channel section in the second cooling channel 43B, and heat exchange takes place between the heat transfer medium and the replacement battery 31, thereby cooling the replacement battery 31.

[0031] The third cooling channel 43C is a channel through which a heat transfer medium flows to the fixed battery unit 2 and the replacement battery unit 3 via the heat exchanger 41. This third cooling channel 43C is formed by fully closing valve 42A (valve for fixed battery) and valve 42B (valve for replacement battery) and fully opening valve 42C (channel connection valve).

[0032] In the third cooling channel 43C, the heat transfer medium cooled by heat exchange in the heat exchanger 41 flows through a meandering channel section provided on the bottom surface of the case 22 of the fixed battery unit 2 and a meandering channel section provided on the bottom surface of the bucket 32 ​​of the replacement battery unit 3. As a result, heat exchange takes place between the heat transfer medium and the fixed battery 21 and the replacement battery 31, respectively, and both the fixed battery 21 and the replacement battery 31 are cooled.

[0033] The heat exchanger (radiator) 41 is connected to pumps 7A and 7B via a cooling passage 43. Pump 7A is connected to the fixed battery unit 2 via the cooling passage 43. Pump 7B is connected to the replacement battery unit 3 via the cooling passage 43. When pumps 7A and 7B are operating, they circulate a heat transfer medium in the cooling passage 43. Pumps 7A and 7B are, for example, water pumps, but are not limited to this and may be any type of pump. The heat transfer medium is, for example, water, but is not limited to this and may be any other liquid, such as coolant (cooling water).

[0034] The control unit 5 is, for example, an ECU (Electronic Control Unit). As shown in Figure 1, in the battery cooling structure 1, the control unit 5 is connected to each of the valves 42A to 42C, pumps 7A and 7B, and sensors 6A and 6B via the bus 8.

[0035] When the control unit 5 receives temperature t data for the fixed battery 21 and replacement battery 31 detected by sensors 6A and 6B via the bus 8, it controls the cooling unit 4 based on the temperature t data and performs temperature control for the necessary batteries among the fixed battery 21 and replacement battery 31.

[0036] Based on the temperature t data obtained from sensors 6A and 6B, the control unit 5 controls the opening and closing of the valves to set one of the first cooling passage 43A, the second cooling passage 43B, or the third cooling passage 43C based on the temperature t of the fixed battery 21 and the replacement battery 31, if at least one of the fixed battery 21 and the replacement battery 31 has a temperature t exceeding the appropriate temperature range TW.

[0037] Here, the "appropriate temperature range TW" may be, for example, 5°C to 40°C, but is not limited to this. The lowest temperature t within this "appropriate temperature range TW" is called the "low-temperature threshold TL," and the highest temperature t within this "appropriate temperature range TW" is called the "high-temperature threshold TH."

[0038] For example, if the temperature t of only the fixed battery 21 exceeds the appropriate temperature range TW (i.e., exceeds the high-temperature threshold TH) of the fixed battery 21 and the replacement battery 31, the control unit 5 controls the valve 42A to open and the valves 42B and 42C to close. This forms the first cooling channel 43A. In this case, the control unit 5 controls the pump 7A to operate. As a result, the heat transfer medium cooled in the heat exchanger (radiator) 41 passes through the pump 7A of the first cooling channel 43A and is introduced into the meandering channel section provided on the bottom surface of the case 22 of the fixed battery unit 2.

[0039] In this way, heat exchange takes place between the cooled heat transfer medium and the stationary battery 21, cooling the stationary battery 21. Subsequently, in the first cooling channel 43A, the heat transfer medium flows out from the stationary battery unit 2, passes through the open valve 42A, and returns to the heat exchanger 41. The control unit 5 continues to cool the stationary battery 21 with the heat transfer medium flowing through the first cooling channel 43A until the temperature t of the stationary battery 21 falls within the appropriate temperature range TW (i.e., below its high-temperature threshold TH).

[0040] Furthermore, for example, if the temperature t of only the replacement battery 31 exceeds the appropriate temperature range TW (i.e., exceeds its high-temperature threshold TH) among the fixed battery 21 and the replacement battery 31, the control unit 5 controls the valve 42B to open and the valves 42A and 42C to close. This forms the second cooling channel 43B. In this case, the control unit 5 controls the pump 7B to operate. As a result, the heat transfer medium cooled in the heat exchanger (radiator) 41 passes through the pump 7B of the second cooling channel 43B and is introduced into the meandering channel portion provided on the bottom surface of the bucket 32 ​​of the replacement battery unit 3.

[0041] In this way, heat exchange takes place between the cooled heat transfer medium and the replacement battery 31, cooling the replacement battery 31. Subsequently, in the second cooling channel 43B, the heat transfer medium flows out from the replacement battery unit 3, passes through the open valve 42B, and returns to the heat exchanger 41. The control unit 5 continues to cool the replacement battery 31 with the heat transfer medium flowing through the second cooling channel 43B until the temperature t of the replacement battery 31 falls within the appropriate temperature range TW (i.e., below its high-temperature threshold TH).

[0042] Furthermore, for example, if the temperature t of both the fixed battery 21 and the replacement battery 31 exceeds the appropriate temperature range TW (i.e., exceeds the high-temperature threshold TH), the control unit 5 controls the valve 42C to open and the valves 42A and 42B to close. This forms the third cooling channel 43C. In this case, the control unit 5 controls either the pump 7A or 7B to operate.

[0043] For example, when the control unit 5 controls the pump 7A to operate, the heat medium cooled in the heat exchanger (radiator) 41 passes through the pump 7A in the third cooling channel 43C and is introduced into a meandering channel portion provided on the bottom surface of the case 22 of the fixed battery unit 2. Thereby, heat exchange is performed between the cooled heat medium and the fixed battery 21, and the fixed battery 21 is cooled.

[0044] After that, in the third cooling channel 43C, the heat medium flowing out from the fixed battery unit 2 passes through the opened valve 42C and is then introduced into a meandering channel portion provided on the bottom surface of the bucket 32 of the exchange battery unit 3. Thereby, heat exchange is performed between the cooled heat medium and the exchange battery 31, and the exchange battery 31 is cooled.

[0045] After that, in the third cooling channel 43C, the heat medium flowing out from the exchange battery unit 3 passes through the pump 7B and returns to the heat exchanger 41. The control unit 5 continues to cool the fixed battery 21 and the exchange battery 31 by the heat medium flowing through the third cooling channel 43C until the temperatures t of both the fixed battery 21 and the exchange battery 31 are within the appropriate temperature range TW (that is, below the high temperature side threshold TH).

[0046] Next, the case where there is a battery whose temperature t is less than the appropriate temperature range TW (that is, less than the low temperature side threshold TL) among the fixed battery 21 and the exchange battery 31 will be described. In the present embodiment, the case where the temperatures t of both the fixed battery 21 and the exchange battery 31 are less than the appropriate temperature range TW is not assumed. Therefore, the "case where there is a battery with a temperature less than the appropriate temperature range TW among the fixed battery 21 and the exchange battery 31" here means the case where the temperature t of either one of the fixed battery 21 and the exchange battery 31 is less than the appropriate temperature range TW.

[0047] When the temperature t of the fixed battery 21 or the replaceable battery 31 is lower than the appropriate temperature range TW (for example, lower than 5°C), there may be problems such as the inability to perform rapid charging. Therefore, when the temperature t of one of the fixed battery 21 and the replaceable battery 31 is lower than the appropriate temperature range TW (that is, lower than its low-temperature threshold value TL), the control unit 5 preheats (warms up) the battery that is lower than the appropriate temperature range TW (that is, lower than its low-temperature threshold value TL).

[0048] In this case, in the third cooling channel 43C, the control unit 5 controls the opening and closing of the valves 42A to 42C and the operation of the corresponding pump among the pumps 7A and 7B so that the heat medium warmed by flowing through the battery unit having the other battery (the battery within the appropriate temperature range TW (that is, the battery above its low-temperature threshold value TL)) among the fixed battery 21 and the replaceable battery 31 flows to the battery unit having one battery (the battery lower than the appropriate temperature range TW (that is, lower than its low-temperature threshold value TL)).

[0049] For example, when the temperature t of the replaceable battery 31 is lower than the appropriate temperature range TW (that is, lower than its low-temperature threshold value TL) (in this case, the temperature t of the fixed battery 21 is above the low-temperature threshold value TL), the control unit 5 opens the valve 42C, closes the valves 42A and 42B to form the third cooling channel 43C. At the same time, the control unit 5 controls the operation of the pump 7A. As a result, in the formed third cooling channel 43C, immediately after the start of the operation of the pump 7A, the heat medium warmed by the fixed battery 21 by flowing through the fixed battery unit 2 flows to the replaceable battery unit 3 having the replaceable battery 31.

[0050] In this way, heat exchange is performed between the heat medium warmed by the fixed battery 21 and the replaceable battery 31 with a temperature t lower than the low-temperature threshold value TL, and the temperature t of the replaceable battery 31 rises (preheat treatment of the battery).

[0051] By such preheat treatment of the battery, when the temperatures t of the fixed battery 21 and the replaceable battery 31 become higher than the low-temperature threshold value TL of the appropriate temperature range TW (for example, 5°C or higher), it is possible to prevent the occurrence of problems such as the inability to perform rapid charging.

[0052] Next, the operation process of the control unit 5 in the battery cooling structure 1 according to the first embodiment will be explained with reference to the flowchart in Figure 2. In step S1, the control unit 5 determines whether there is a battery among the fixed battery 21 and the replacement battery 31 whose temperature t is below the appropriate temperature range TW (i.e., below the low-temperature threshold TL). In other words, the control unit 5 determines whether the temperature t of either the fixed battery 21 or the replacement battery 31 is below the low-temperature threshold TL.

[0053] In step S1, if the control unit 5 determines that there is a battery whose temperature t is below the low-temperature threshold TL, that is, if the temperature t of either the fixed battery 21 or the replacement battery 31 is below the low-temperature threshold TL (YES in step S1), it proceeds to step S2 in order to preheat (heat) the battery whose temperature t is below the low-temperature threshold TL.

[0054] In step S2, the control unit 5 fully opens valve 42C and fully closes valves 42A and 42B to form a third cooling channel 43C. At the same time, the control unit 5 controls a specific pump (specific pump) among the pumps 7A and 7B to operate in the fixed battery unit 2 and the replacement battery unit 3 so that the heat transfer medium flows from the battery unit having batteries with a temperature t of TL or higher to the battery unit having batteries with a temperature t of TL or lower (battery preheating treatment).

[0055] For example, if the temperature t of the fixed battery 21 is above the low-temperature threshold TL, and the temperature t of the replacement battery 31 is below the low-temperature threshold TL, the control unit 5 controls the operation of a specific pump, pump 7A. This causes the heat transfer medium, heated by heat exchange with the fixed battery 21, to flow to the replacement battery unit 3 immediately after the pump 7A starts operating, thereby performing a preheating treatment to raise the temperature t of the replacement battery 31.

[0056] In step S3, following step S2, the control unit 5 determines whether the temperature t of the fixed battery 21 and the replacement battery 31 is above the low-temperature threshold TL. In step S3, if the control unit 5 determines that the temperature t of both the fixed battery 21 and the replacement battery 31 is above the low-temperature threshold TL (YES in step S3), it proceeds to step S4 to terminate the battery preheating process. In step S4, the control unit 5 terminates the battery preheating process by controlling the valve 42C to be completely closed and by controlling the specific pump that was operated in step S2 to be stopped.

[0057] On the other hand, in step S3, if the control unit 5 determines that the temperature t of either the fixed battery 21 or the replacement battery 31 is still below the low-temperature threshold TL (NO in step S3), it returns to the process of step S3. As a result, the process of flowing the heat transfer medium from the battery unit having batteries with a temperature t of TL or higher to the battery unit having batteries with a temperature t of below the low-temperature threshold TL (step S2) continues. In step S3, when the control unit 5 determines that the temperature t of both the fixed battery 21 and the replacement battery 31 is TL or higher, it proceeds to the following step S4 to terminate the battery preheating process.

[0058] In step S1 described above, if the control unit 5 determines that there are no batteries whose temperature t is below the low-temperature threshold TL, that is, if the temperature t of both the fixed battery 21 and the replacement battery 31 is above the low-temperature threshold TL (NO in step S1), then there is no need to preheat the batteries, and the process proceeds to step S5 without performing steps S2 to S4.

[0059] In step S5, the control unit 5 determines whether there is a battery among the fixed battery 21 and the replacement battery 31 whose temperature t exceeds the appropriate temperature range TW (i.e., exceeds the high temperature threshold TH). In step S5, if the control unit 5 determines that there is a battery whose temperature t exceeds the high temperature threshold TH, that is, if the temperature t of at least one of the fixed battery 21 and the replacement battery 31 exceeds the high temperature threshold TH (YES in step S5), it proceeds to step S6 to determine which battery to cool.

[0060] On the other hand, in step S5, if the control unit 5 determines that there are no batteries whose temperature t exceeds the high-temperature threshold TH, that is, that the temperature t of both the fixed battery 21 and the replacement battery 31 is within the appropriate temperature range TW (i.e., below the high-temperature threshold TH) (NO in step S5), then there is no need to cool the batteries, and the series of processes shown in Figure 2 is terminated.

[0061] In step S6, based on the determination made in step S5, the control unit 5 determines whether or not to cool the fixed battery 21 because its temperature t exceeds the high-temperature threshold TH. In step S6, if the control unit 5 determines that the fixed battery 21 should be cooled because its temperature t exceeds the high-temperature threshold TH (YES in step S6), it proceeds to step S7 to determine whether to also cool the replacement battery 31. On the other hand, in step S6, if the control unit 5 determines that the fixed battery 21 should not be cooled (i.e., only the replacement battery 31 should be cooled) because its temperature t does not exceed the high-temperature threshold TH (it is below the high-temperature threshold TH) (NO in step S6), it proceeds to step S10 to cool the replacement battery 31.

[0062] In step S7, following step S6, the control unit 5 determines, based on the determination made in step S5, whether or not to cool the replacement battery 31 because its temperature t exceeds the high-temperature threshold TH. In other words, the control unit 5 determines whether or not to cool not only the fixed battery 21, which was determined to be cooled in step S6, but also the replacement battery 31. In step S6, if the control unit 5 determines that the replacement battery 31 should also be cooled because its temperature t exceeds the high-temperature threshold TH (YES in step S7), it proceeds to step S8 to cool both the fixed battery 21 and the replacement battery 31. On the other hand, in step S7, if the control unit 5 determines that the replacement battery 31 should not be cooled and only the fixed battery 21 should be cooled because its temperature t does not exceed the high-temperature threshold TH (it is below the high-temperature threshold TH) (NO in step S7), it proceeds to step S9 to cool only the fixed battery 21.

[0063] In step S8, the control unit 5 controls valve 42C to be fully open and valves 42A and 42B to be fully closed in order to cool both the fixed battery 21 and the replacement battery 31, thereby forming a third cooling channel 43C. The control unit 5 also controls the operation of either pump 7A or pump 7B. At this point, the control unit 5 may operate either pump 7A or pump 7B. Through the process in step S8, both the fixed battery 21 and the replacement battery 31 are cooled by the heat transfer medium cooled by the heat exchanger (radiator) 41.

[0064] In step S9, the control unit 5 controls valve 42A to be fully open and valves 42B and 42C to be fully closed in order to cool only the fixed battery 21, thereby forming a first cooling channel 43A. The control unit 5 also controls pump 7A to circulate the heat transfer medium in this first cooling channel 43A. As a result of the process in step S9, the fixed battery 21 is cooled by the heat transfer medium cooled by heat exchange in the heat exchanger (radiator) 41.

[0065] In step S10, the control unit 5 controls valve 42B to be fully open and valves 42A and 42C to be fully closed in order to cool only the replacement battery 31, thereby forming a second cooling channel 43B. The control unit 5 also controls pump 7B to circulate the heat transfer medium in this second cooling channel 43B. Through this process in step S10, the replacement battery 31 is cooled by the heat transfer medium cooled by heat exchange in the heat exchanger (radiator) 41.

[0066] In step S8, step S9, or step S11 following step S10, the control unit 5 determines whether the temperature t of the fixed battery 21 and the replacement battery 31 is below the high-temperature threshold TH. In step S11, if the control unit 5 determines that the temperature t of the fixed battery 21 and the replacement battery 31 is below the high-temperature threshold TH (YES in step S11), it proceeds to step S12 to terminate the battery cooling process.

[0067] On the other hand, in step S11 described above, if the control unit 5 determines that the temperature t of at least one or both of the fixed battery 21 and the replacement battery 31 still exceeds the high-temperature threshold TH (NO in step S11), it returns to the process of step S11. As a result, one of the processes of steps S8, S9, or S10 described above continues. In step S11, when the control unit 5 determines that the temperature t of both the fixed battery 21 and the replacement battery 31 is below the high-temperature threshold TH, it proceeds to the following step S12 to terminate the battery cooling process.

[0068] In step S12, the control unit 5 controls all of the valves 42A to 42C to be completely closed. The control unit 5 also controls the pump that was operated in step S8, step S9, or step S10 to be stopped. As a result, the control unit 5 finishes the battery cooling process and completes the series of processes shown in Figure 2.

[0069] As described above, in the battery cooling structure 1 according to the first embodiment, the first cooling passage 43A, the second cooling passage 43B, and the third cooling passage 43C can be switched between each other by opening and closing valves 42A to 42C. In this battery cooling structure 1 according to the first embodiment, when the control unit 5 determines that there is at least one battery among the fixed battery 21 and the replacement battery 31 that has a temperature t exceeding the appropriate temperature range TW, it controls the opening and closing of the corresponding valves to set one of the first cooling passage 43A, the second cooling passage 43B, or the third cooling passage 43C based on the temperature of the fixed battery 21 and the replacement battery 31. As a result, the battery cooling structure 1 according to the first embodiment cools the battery among the fixed battery 21 and the replacement battery 31 that has a temperature t exceeding the appropriate temperature range TW.

[0070] Furthermore, when the control unit 5 determines that the temperature t of one of the fixed battery 21 and the replacement battery 31 is below the appropriate temperature range TW, it controls the opening and closing of the corresponding valve and the operation of the pumps 7A and 7B that circulate the heat transfer medium in the third cooling channel 43C, so as to circulate the heat transfer medium that has flowed through the battery unit having the other battery to the battery unit having the other battery. In this way, the battery cooling structure 1 according to the first embodiment preheats (heats) the battery among the fixed battery 21 and the replacement battery 31 whose temperature t is below the appropriate temperature range TW.

[0071] According to the battery cooling structure 1 of this first embodiment, the temperature t of the fixed battery 21 and the replacement battery 31 can be appropriately adjusted based on the temperature t of the fixed battery 21 and the replacement battery 31 mounted on the vehicle 100. As a result, the battery cooling structure 1 of the first embodiment makes it possible to maintain the battery performance of the fixed battery 21 and the replacement battery 31.

[0072] It should be noted that the processing performed by the control unit 5 described in this first embodiment is performed, on the premise that the replacement battery 31 is not being replaced (non-replacement). For example, when a user, employee of a highway service area or service station, etc., is performing the replacement work of attaching and detaching the replacement battery 31 to the bucket 32, it is dangerous if the temperature of the replacement battery 31 being removed from the bucket 32 ​​is high.

[0073] Therefore, when such a replacement operation of the replacement battery 31 is performed, the control unit 5 acquires information (replacement operation execution information) indicating that the replacement operation of the replacement battery 31 is to be performed, based on the user's operation instructions as described above. Based on the acquired replacement operation execution information, the control unit 5 may, instead of processing as shown in the flowchart in Figure 2, prioritize cooling the replacement battery 31 so that the temperature remains below the safe operating temperature threshold TS (for example, 35°C or below) even when the replacement operation of the replacement battery 31 is performed.

[0074] In this process, the control unit 5 controls the opening and closing of valves 42A to 42C to form the second cooling channel 43B and also controls the operation of the pump 7B. As a result, the heat transfer medium cooled in the heat exchanger (radiator) 41 passes through the pump 7B in the second cooling channel 43B and is introduced into the meandering channel portion provided on the bottom surface of the bucket 32 ​​of the replacement battery unit 3. The replacement battery 31 may be cooled in this manner.

[0075] [Second Embodiment] Next, a second embodiment of the present invention (hereinafter also simply referred to as the "second embodiment") will be described. The battery cooling structure 1 according to the second embodiment has the configuration shown in Figure 1. Therefore, the same reference numerals as in Figure 1 will be used to describe the second embodiment. However, in the second embodiment, if both the fixed battery 21 and the replacement battery 31 have a temperature t that exceeds the appropriate temperature range TW, the control unit 5 determines the cooling priority E (priority E1 (high), priority E2 (low)) for the fixed battery 21 and the replacement battery 31 based on at least the temperature t of the fixed battery 21 and the replacement battery 31.

[0076] The control unit 5 then controls the opening and closing of valves and the operation of pumps that circulate the heat transfer medium in the third cooling channel 43C, so that the heat transfer medium flowing out of the heat exchanger 41 flows to battery units having batteries with a high cooling priority E, and then to battery units having batteries with a low cooling priority E.

[0077] Here, the operation processing of the control unit 5 in the battery cooling structure 1 according to the second embodiment will be explained with reference to the flowchart in Figure 3. As shown in Figure 3, the control unit 5 performs the same processing as steps S1 to S4 in Figure 2 as the processing in steps S21 to S24 (battery preheating processing). The control unit 5 also performs the same processing as steps S5 to S7 in Figure 2 as the processing in steps S25 to S27, and performs the same processing as steps S9 and S10 in Figure 2 as the processing in steps S30 and S31 (battery cooling processing).

[0078] As shown in Figure 3, if the control unit 5 determines YES in step S27, that is, if it determines that both the fixed battery 21 and the replacement battery 31 should be cooled because the temperature t of both the fixed battery 21 and the replacement battery 31 exceeds the high-temperature threshold TH, it proceeds to step S28 following step S27. In step S28, the control unit 5 determines the cooling priority E for the fixed battery 21 and the replacement battery 31 based on, for example, the temperature t of the fixed battery 21 and the replacement battery 31 (and, if necessary, other information such as total energy [Wh], SOC (State Of Charge) [%], discharge capacity [mAh], voltage [V]).

[0079] For example, suppose the appropriate temperature range TW is 5°C to 40°C (i.e., high-temperature threshold TH = 40°C, low-temperature threshold TL = 5°C), and the temperature t of the fixed battery 21 is 50°C, and the temperature t of the replacement battery 31 is 45°C. In this case, the control unit 5 determines a cooling priority E1 (high) for the fixed battery 21, which has a higher temperature t, and a cooling priority E2 (low) for the replacement battery 31, which has a lower temperature t, based on the temperature data of the fixed battery 21 (50°C) and the temperature data of the replacement battery 31 (45°C) obtained from sensors 6A and 6B. In other words, the control unit 5 decides to preferentially cool the fixed battery 21, which has a higher temperature t, with the heat transfer medium cooled by the heat exchanger (radiator) 41.

[0080] For example, the control unit 5 may determine a cooling priority E1 (high) for the battery with a larger total energy [Wh] and a cooling priority E2 (low) for the battery with a smaller total energy [Wh] when the temperatures t of the fixed battery 21 and the replacement battery 31 are the same and both exceed the high-temperature threshold TH.

[0081] As a specific example, suppose the appropriate temperature range TW is 5°C to 40°C (i.e., high-temperature threshold TH = 40°C, low-temperature threshold TL = 5°C), the temperature t of the fixed battery 21 and the replacement battery 31 are the same temperature (e.g., 50°C) that exceeds the high-temperature threshold TH, and the total energy [Wh] of the fixed battery 21 is greater than the total energy [Wh] of the replacement battery 31. In this case, the control unit 5 acquires temperature data (e.g., 50°C) of the fixed battery 21 and the replacement battery 31 from sensors 6A and 6B, along with, for example, data on the total energy [Wh] of the fixed battery 21 and data on the total energy [Wh] of the replacement battery 31.

[0082] In this case, the control unit 5 determines a cooling priority E1 (high) for the fixed battery 21, which has a larger total energy [Wh], and a cooling priority E2 (low) for the replacement battery 31, which has a smaller total energy [Wh] than the fixed battery 21. That is, if the temperature t is the same for the fixed battery 21 and the replacement battery 31, the control unit 5 decides to preferentially cool the fixed battery 21, which has a larger total energy [Wh], with the heat transfer medium cooled by the heat exchanger (radiator) 41.

[0083] Alternatively, for example, the control unit 5 may determine a cooling priority E1 (high) for the battery with a higher SOC (State Of Charge) [%] and a cooling priority E2 (low) for the battery with a lower SOC [%] when the temperatures t of the fixed battery 21 and the replacement battery 31 are the same temperature, both exceeding the high-temperature threshold TH. In other words, the control unit 5 may decide to preferentially cool the battery with a higher SOC [%] using the heat transfer medium cooled by the heat exchanger (radiator) 41.

[0084] Alternatively, for example, the control unit 5 may determine a cooling priority E1 (high) for the battery with a larger discharge capacity [mAh] and a cooling priority E2 (low) for the battery with a smaller discharge capacity [mAh] when the temperatures t of the fixed battery 21 and the replacement battery 31 are the same temperature, both exceeding the high-temperature threshold TH. In other words, the control unit 5 may decide to preferentially cool the battery with a larger discharge capacity [mAh] using the heat transfer medium cooled by the heat exchanger (radiator) 41.

[0085] Alternatively, for example, the control unit 5 may determine a cooling priority E1 (high) for the battery with a higher voltage [V] and a cooling priority E2 (low) for the battery with a lower voltage [V] when the temperatures t of the fixed battery 21 and the replacement battery 31 are the same temperature, both exceeding the high-temperature threshold TH. In other words, the control unit 5 may decide to preferentially cool the battery with a higher voltage [V] using the heat transfer medium cooled by the heat exchanger (radiator) 41.

[0086] In step S29, following step S28, the control unit 5 controls valve 42C to be fully open and valves 42A and 42B to be fully closed, thereby forming a third cooling channel 43C. At the same time, the control unit 5 identifies the corresponding pump (specific pump) from pumps 7A and 7B in order to first flow the heat transfer medium cooled by the heat exchanger (radiator) 41 to the battery with priority E1 (high), and then to the battery with priority E2 (low).

[0087] For example, if the cooling priority E for the fixed battery 21 is priority E1 (high) and the cooling priority E for the replacement battery 31 is priority E2 (low), the control unit 5 will designate pump 7A as a specific pump so that the heat transfer medium cooled by the heat exchanger (radiator) 41 is first flowed to the fixed battery unit 2 having the fixed battery 21 with priority E1 (high), and then to the replacement battery unit 3 having the replacement battery 31 with priority E2 (low).

[0088] The control unit 5 controls the operation of the identified pump (specific pump). After processing in step S29, the control unit 5 proceeds to step S32. In steps S32 and S33, the control unit 5 performs the same processing as in steps S11 and S12 in Figure 2, and then completes the series of processes shown in Figure 3.

[0089] As described above, in the battery cooling structure 1 according to the second embodiment, a cooling priority E is determined for the fixed battery 21 and the replacement battery 31 mounted on the vehicle 100 based on at least their temperature t (or temperature t and other state information), and the direction in which the cooled heat transfer medium flows is determined based on the cooling priority E. As a result, in the battery cooling structure 1 according to the second embodiment, the heat transfer medium cooled by heat exchange in the heat exchanger (radiator) 41 is flowed to the battery unit having a higher cooling priority E before the battery unit having a lower cooling priority E, thus enabling more efficient cooling. Therefore, the battery cooling structure 1 according to the second embodiment allows for more appropriate adjustment of the temperature t of the fixed battery 21 and the replacement battery 31. Consequently, the battery cooling structure 1 according to the second embodiment makes it possible to further improve the maintenance of the battery performance of the fixed battery 21 and the replacement battery 31.

[0090] [Third Embodiment] Next, a third embodiment of the present invention (hereinafter also simply referred to as the "third embodiment") will be described. The battery cooling structure 1 according to the third embodiment basically has the same configuration as shown in Figure 1. Therefore, in the third embodiment as well, the same configuration as in Figure 1 will be described using the reference numerals shown in Figure 1. However, the third cooling channel formed in the third embodiment has a different configuration from the third cooling channel 43C formed in the first and second embodiments, and therefore is not given a reference numeral in Figure 1.

[0091] In the third embodiment, similar to the second embodiment, if both the fixed battery 21 and the replacement battery 31 have a temperature t that exceeds the appropriate temperature range TW, the control unit 5 determines the cooling priority E (priority E1 (high), priority E2 (low)) for the fixed battery 21 and the replacement battery 31 based on at least the temperature t of the fixed battery 21 and the replacement battery 31.

[0092] The third cooling channel (not indicated by a reference numeral) formed in the third embodiment is a channel through which a heat transfer medium flows to the fixed battery unit 2 and the replacement battery unit 3 via the heat exchanger (radiator) 41, similar to the third cooling channel 43C formed in the first and second embodiments. However, the third cooling channel formed in this third embodiment is configured such that the heat transfer medium cooled in the heat exchanger (radiator) 41 passes through one of the fixed battery unit 2 and the replacement battery unit 3 and returns to the heat exchanger 41, and then, after being cooled again in the heat exchanger (radiator) 41, the heat transfer medium passes through the other of the fixed battery unit 2 and the replacement battery unit 3 and returns to the heat exchanger 41. Therefore, the channel configuration in the third embodiment is different from the channel configuration in the first and second embodiments. The third cooling channel in this third embodiment is formed by fully closing valve 42C and opening valves 42A and 42B at adjusted openings.

[0093] In the battery cooling structure 1 according to the third embodiment, for example, when the control unit 5 controls the operation of the pump 7A in this third cooling channel (not indicated by a reference numeral), the heat transfer medium cooled in the heat exchanger (radiator) 41 passes through the pump 7A, then flows through a meandering channel section provided on the bottom surface of the case 22 of the fixed battery unit 2, and then passes through the valve 42A to return to the heat exchanger 41. After that, the heat transfer medium is cooled again in the heat exchanger (radiator) 41, then passes through the valve 42B and flows through a meandering channel section provided on the bottom surface of the bucket 32 ​​of the replacement battery unit 3, and then passes through the pump 7B to return to the heat exchanger 41.

[0094] In addition, the control unit 5 may operate pump 7B instead of pump 7A in the third cooling channel (not indicated by a reference numeral) of this third embodiment.

[0095] In the third cooling channel (not indicated by a reference numeral) formed in the third embodiment, the control unit 5 performs opening and closing control of valves 42A and 42B so that the flow rate of the heat transfer medium supplied to the battery with priority E1 (high) among the fixed battery 21 and the replacement battery 31 is greater than the flow rate of the heat transfer medium supplied to the battery with priority E2 (low).

[0096] For example, if the control unit 5 determines a priority E1 (high) for the fixed battery 21 and a priority E2 (low) for the replacement battery 31, it performs opening and closing control in the third cooling channel (not indicated by a reference numeral) formed in this third embodiment, adjusting the opening of valve 42A to a larger opening than the opening of valve 42B so that the flow rate of the heat transfer medium flowing to the fixed battery 21 is greater than the flow rate of the heat transfer medium flowing to the replacement battery 31.

[0097] As a more specific example, if the appropriate temperature range TW is 5°C to 40°C, and the temperature t of the fixed battery 21 with priority E1 (high) is 50°C, and the temperature t of the replacement battery 31 with priority E2 (low) is 45°C, the control unit 5 will control the valves to adjust the opening of valve 42A to 70% and valve 42B to 50%. Alternatively, if the temperature t of the fixed battery 21 with priority E1 (high) is 65°C, and the temperature t of the replacement battery 31 with priority E2 (low) is 60°C, the control unit 5 will control the valves to adjust the opening of valve 42A to 95% and valve 42B to 75%.

[0098] Thus, the control unit 5 may adjust the degree to which the valve is opened according to the temperature t of the fixed battery 21 and the replacement battery 31. For example, the control unit 5 may adjust the valve to open more as the temperature t of the fixed battery 21 and the replacement battery 31 increases.

[0099] In the operation processing of the control unit 5 in the battery cooling structure 1 according to this third embodiment, the following processing is performed instead of the processing of step S29 in the flowchart of Figure 3 described above, and otherwise the same processing as shown in the flowchart of Figure 3 (steps S21 to S28, steps S30 to S33 described above) is performed.

[0100] In other words, instead of the process in step S29 described above, the control unit 5 controls valve 42C to be fully closed in order to form the third cooling channel (not indicated by a reference numeral) of the third embodiment. At the same time, the control unit 5 controls the opening of valves 42A and 42B so that the flow rate of the heat transfer medium supplied to the battery with priority E1 (high) among the fixed battery 21 and the replacement battery 31 is greater than the flow rate of the heat transfer medium supplied to the battery with priority E2 (low).

[0101] As described above, in the battery cooling structure 1 according to the third embodiment, a cooling priority E (priority E1 (high), priority E2 (low)) is determined for the fixed battery 21 and the replacement battery 31 mounted on the vehicle 100 based on at least their temperature t (or temperature t and other state information), and the flow rate of the cooled heat transfer medium is changed based on the cooling priority E. As a result, the battery cooling structure 1 according to the third embodiment can perform the cooling process more efficiently than the first embodiment. Therefore, the battery cooling structure 1 according to the third embodiment can adjust the temperature t of the fixed battery 21 and the replacement battery 31 more appropriately. Consequently, the battery cooling structure 1 according to the third embodiment makes it possible to further improve the maintenance of the battery performance of the fixed battery 21 and the replacement battery 31.

[0102] Although the first to third embodiments of the present invention have been described in detail above with reference to the drawings, the specific configurations are not limited to these embodiments, and any design changes, etc., that do not depart from the gist of the present invention are also included. Furthermore, the examples described above can be combined by utilizing each other's technologies, as long as there are no particular contradictions or problems in their purpose and configuration.

[0103] For example, instead of the above example, the number of replacement batteries 31 in the replacement battery unit 3 may be two or more. In this case, instead of the above example, the control unit 5 may, for example, perform the same cooling treatment on all of the two or more replacement batteries 31 as performed on the replacement battery 31 above when the temperature t of at least one of the two or more replacement batteries 31 exceeds the high-temperature threshold TH. Also, if the number of replacement batteries 31 in the replacement battery unit 3 is two or more, the control unit 5 may, instead of the above example, perform the same preheating treatment on all of the two or more replacement batteries 31 as performed on the replacement battery 31 above when the temperature t of at least one of the two or more replacement batteries 31 falls below the low-temperature threshold TL.

[0104] Alternatively, instead of the above example, the heat transfer medium may be a gas such as air. In that case, the configuration of the cooling unit 4, including the cooling channel 43 described above, may be appropriately modified to be suitable for air cooling.

[0105] 1: Battery cooling structure, 2: Fixed battery unit, 3: Replacement battery unit, 4: Cooling section, 5: Control unit, 6A, 6B: Sensors, 7A, 7B: Pumps, 8: Bus, 21: Fixed battery, 22: Case, 31: Replacement battery, 32: Bucket, 41: Heat exchanger, 42A-42C: Valves, 43: Cooling passage, 43A: First cooling passage, 43B: Second cooling passage, 43C: Third cooling passage, 100: Vehicle

Claims

1. A cooling structure for a vehicle battery that cools at least one of a fixed battery permanently installed in a vehicle and a replaceable battery that is replaceable in a vehicle, comprising: a fixed battery unit having the fixed battery; a replaceable battery unit having the replaceable battery; a cooling section that cools at least one of the fixed battery and the replaceable battery; and a control unit that controls the cooling section, wherein the cooling section comprises a heat exchanger and a cooling passage for flowing a heat transfer medium, comprising: a first cooling passage that flows the heat transfer medium to the fixed battery unit via the heat exchanger; a second cooling passage that flows the heat transfer medium to the replaceable battery unit via the heat exchanger; and a third cooling passage that flows the heat transfer medium to the fixed battery unit and the replaceable battery unit via the heat exchanger, which can be switched and set by opening and closing a valve, wherein the control unit, when there is at least one battery among the fixed battery and the replaceable battery that has a temperature exceeding the appropriate temperature range, A cooling structure for a vehicle battery, characterized in that the opening and closing of the valve is controlled to set one of the first cooling passage, the second cooling passage, or the third cooling passage based on the temperature of the fixed battery and the replacement battery.

2. The cooling structure for a vehicle battery according to claim 1, characterized in that, when the temperature of one of the fixed battery and the replacement battery is below the appropriate temperature range, the control unit controls the opening and closing of the valve and the operation of the pump that flows the heat transfer medium in the third cooling channel so that the heat transfer medium that has flowed through the battery unit having the other of the fixed battery and the replacement battery flows to the battery unit having the one battery.

3. The vehicle battery cooling structure according to claim 1, characterized in that, when both the fixed battery and the replacement battery have temperatures exceeding the appropriate temperature range, the control unit determines the cooling priority for the fixed battery and the replacement battery based on at least the temperatures of the fixed battery and the replacement battery, and controls the opening and closing of the valve and the operation of the pump that flows the heat transfer medium in the third cooling channel, so as to flow the heat transfer medium flowing out of the heat exchanger to the battery unit having the battery with the higher cooling priority, and then to the battery unit having the battery with the lower cooling priority.

4. A vehicle equipped with the vehicle battery cooling structure described in claim 1.

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