Temperature control device and temperature control method for secondary battery

Abstract

To achieve both improvement of energy density of a secondary battery and suppression of spreading fire.SOLUTION: A secondary battery temperature control device 1 includes a first cell 21 having a first main surface, a second cell 22 having a second main surface opposite to the first main surface, a first coolant passage 32 located between the first main surface and the second main surface and configured to cool the first cell through the first main surface and cool the second cell through the second main surface by a coolant flowing therethrough, and an on-off valve 45 configured to open the first coolant passage so that the coolant is discharged from the first coolant passage when a temperature of the first cell exceeds a predetermined temperature.SELECTED DRAWING: Figure 5A

Description

[Technical Field]

[0001] The technology disclosed herein relates to a temperature control device and a temperature control method for a secondary battery. [Background technology]

[0002] Patent Document 1 describes a conventional battery pack. The conventional battery pack includes a plurality of battery cells arranged side by side. The battery cells have a storage section that stores a storage element including an electrode sheet, an electrolyte, and a separator. The battery cells also have an expansion section that is integrated with the storage section. When the storage element generates heat, gas generated inside the storage section flows from the internal space of the storage section into the internal space of the expansion section. The expansion section expands due to the inflow of gas, increasing the distance between the battery cells and preventing fires from spreading. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2021-170513 Summary of the Invention [Problem to be solved by the invention]

[0004] Narrowing the gap between adjacent cells can improve the energy density of a secondary battery. However, narrowing the gap between adjacent cells makes it easier for heat to be transferred to the adjacent cell if one of the cells experiences an abnormal temperature. This narrow gap between adjacent cells also makes the secondary battery more susceptible to fire.

[0005] The technology disclosed herein achieves both an improvement in the energy density of a secondary battery and suppression of the spread of fire. [Means for solving the problem]

[0006] Providing a refrigerant passage between adjacent cells increases the cooling area of ​​the cells, which is effective in increasing the cooling efficiency of the cells and also improves the energy density of the secondary battery.The technology disclosed herein is characterized by using the refrigerant passage between adjacent cells to prevent the spread of fire when a temperature abnormality occurs in one of the cells.

[0007] Specifically, the technology disclosed herein relates to a temperature control device for a secondary battery. a first cell having a first major surface; a second cell having a second major surface opposite to the first major surface; a first refrigerant passage located between the first main surface and the second main surface, through which a refrigerant flows to cool the first cells through the first main surface and the second cells through the second main surface; an on-off valve that opens the first refrigerant passage so that the refrigerant is discharged from the first refrigerant passage when the temperature of the first cell exceeds a predetermined temperature;

[0008] The first refrigerant passage is located between the first main surface of the first cell and the second main surface of the second cell. The refrigerant flowing through the first refrigerant passage cools the first cell through the first main surface and the second cell through the second main surface. Since the first cell and the second cell are cooled through the large-area first main surface and second main surface, respectively, the first cell and the second cell are effectively cooled. The first refrigerant passage enables rapid charging of the secondary battery. Furthermore, by effectively cooling the first cell and the second cell, the gap between the first cell and the second cell can be narrowed. Narrowing the gap between the cells improves the energy density of the secondary battery.

[0009] If the gap between the first cell and the second cell is narrow, there is a risk of fire spreading if a temperature abnormality occurs in the cells. The temperature control device for the secondary battery described above is equipped with an on-off valve. The on-off valve opens the first refrigerant passage when the temperature of the first cell exceeds a predetermined temperature. The refrigerant is discharged from the first refrigerant passage through the on-off valve. The first refrigerant passage between the first cell and the second cell becomes empty, forming an air insulation layer between the first cell and the second cell. Even if the gap between the cells is narrow, the air insulation layer can suppress the transfer of heat from the first cell to the second cell. The air insulation layer between the first cell and the second cell suppresses a temperature rise in the second cell caused by a temperature abnormality in the first cell, thereby suppressing fire spreading in the secondary battery.

[0010] The temperature control device for a secondary battery described above realizes all of the following: improvement in cooling efficiency of the secondary battery, improvement in energy density, and prevention of fire spreading.

[0011] Here, the refrigerant includes water. As will be described later, the refrigerant may be one that vaporizes when an abnormal temperature occurs in the cell. Refrigerants that can be used in the temperature control device for a secondary battery can be appropriately selected from various refrigerants that have a boiling point that is higher than the normal temperature of the cell and lower than the temperature in the abnormal state.

[0012] The temperature control device for the secondary battery includes: a first control valve that opens and closes the first refrigerant passage; a controller that outputs a control signal to the first control valve; a temperature sensor that outputs a measurement signal corresponding to the temperature of the first cell to the controller; The controller may be configured to open the first control valve when the temperature of the first cell is equal to or lower than a predetermined temperature based on a measurement signal from the temperature sensor, thereby allowing the refrigerant to flow through the first refrigerant passage, and to close the first control valve when the temperature of the first cell exceeds the predetermined temperature, thereby stopping the flow of the refrigerant in the first refrigerant passage and vaporizing the refrigerant in the first refrigerant passage.

[0013] When the temperature of the first cell is equal to or lower than a predetermined temperature, the first control valve opens. As the refrigerant flows through the first refrigerant passage, the first cell and the second cell are cooled by the refrigerant flowing through the first refrigerant passage.

[0014] When the temperature of the first cell exceeds a predetermined temperature, the controller closes the first control valve, stopping the flow of refrigerant in the first refrigerant passage. In the first refrigerant passage, the refrigerant receives heat from the first cell and vaporizes, or more precisely, boils. The stirring effect and / or latent heat effect of the refrigerant associated with boiling increases the heat transfer coefficient, effectively cooling the hot first cell. This prevents the secondary battery from spreading.

[0015] The on-off valve may open the first refrigerant passage when an internal pressure of the first refrigerant passage exceeds a predetermined pressure due to evaporation of the refrigerant.

[0016] As the vaporization of the refrigerant in the first refrigerant passage progresses and the internal pressure of the first refrigerant passage exceeds a predetermined pressure, the on-off valve opens, opening the first refrigerant passage. The refrigerant (including the vaporized refrigerant) is discharged from the first refrigerant passage through the on-off valve, emptying the first refrigerant passage. The temperature control device for a secondary battery can effectively cool the abnormally heated first cell by vaporizing the refrigerant, and if the temperature of the first cell still does not decrease, it prevents the spread of fire by making the first refrigerant passage an air insulating layer. The temperature control device for a secondary battery can effectively prevent the spread of fire by using a two-stage measure.

[0017] The temperature control device for the secondary battery includes: a supply path connected to the first refrigerant passage and configured to supply the cooled refrigerant to the first refrigerant passage; a shutoff valve that shuts off the supply path in response to a control signal from the controller; an open valve located in the supply path between the shutoff valve and the first refrigerant passage, and opening the supply path and the first refrigerant passage to the atmosphere, The controller may close the shutoff valve and open the open valve when the temperature of the first cell exceeds a second predetermined temperature after closing the first control valve.

[0018] As described above, when the first control valve closes, the refrigerant evaporates in the first refrigerant passage. As the refrigerant evaporates, the internal pressure of the first refrigerant passage exceeds a predetermined pressure, and the on-off valve opens, opening the first refrigerant passage.

[0019] A supply path is connected to the first refrigerant passage. The supply path supplies cooled refrigerant to the first refrigerant passage. Even if the first refrigerant passage is opened by opening the on-off valve, the first refrigerant passage is unlikely to become empty as long as refrigerant continues to be supplied from the supply path to the first refrigerant passage.

[0020] The shutoff valve shuts off the supply path upon receiving a control signal from the controller. After closing the first control valve, the controller closes the shutoff valve when the temperature of the first cell exceeds a second predetermined temperature. The supply of refrigerant from the supply path to the first refrigerant passage is stopped. The flow of refrigerant in the first refrigerant passage stops. The refrigerant in the first refrigerant passage is likely to vaporize due to the heat of the first cell. Furthermore, as the vaporization of the refrigerant progresses, the on-off valve opens, opening the first refrigerant passage.

[0021] The controller also closes the shutoff valve and opens the open valve. When the open valve is opened, the first refrigerant passage is exposed to the atmosphere, allowing atmospheric pressure to act on the first refrigerant passage. The refrigerant is quickly discharged from the first refrigerant passage through the open on-off valve, preventing the secondary battery from catching fire.

[0022] The temperature control device for the secondary battery includes: a third cell located on the opposite side of the second cell from the first cell and having a fourth main surface facing the third main surface of the second cell; a second refrigerant passage located between the third main surface and the fourth main surface, through which the refrigerant flows to cool the second cells through the third main surface and the third cells through the fourth main surface; a second control valve that opens and closes the second refrigerant passage, When the temperature of the first cell exceeds a predetermined temperature, the controller may close the first control valve to stop the flow of the refrigerant in the first refrigerant passage and keep the second control valve open.

[0023] When a temperature abnormality occurs in the first cell, the first control valve in the first refrigerant passage adjacent to the first cell closes, and as described above, the first cell is effectively cooled by the evaporation of the refrigerant in the first refrigerant passage. The controller keeps the second control valve in the second refrigerant passage not adjacent to the first cell open. Because the refrigerant continues to flow in the second refrigerant passage, the second cell and the third cell are each cooled by the refrigerant flowing through the second refrigerant passage.

[0024] The temperature control device for the secondary battery includes: a fourth cell located on the opposite side of the first cell from the second cell and having a sixth major surface facing the fifth major surface of the first cell; a third refrigerant passage located between the fifth main surface and the sixth main surface, through which the refrigerant flows to cool the first cells through the fifth main surface and the fourth cells through the sixth main surface; a third control valve that opens and closes the third refrigerant passage, The controller may be configured to stop the flow of the refrigerant in the first refrigerant passage and the third refrigerant passage by closing the first control valve and the third control valve when the temperature of the first cell exceeds a predetermined temperature.

[0025] When an abnormal temperature occurs in the first cell, the control valves for the first and third refrigerant passages adjacent to both sides of the first cell, i.e., the first control valve and the third control valve, close. The first cell is effectively cooled from both sides by the evaporation of the refrigerant in the first and third refrigerant passages. This also effectively prevents the first cell from spreading to the second and fourth cells.

[0026] The temperature control device for the secondary battery includes: a first power source; a first circuit that supplies power from the first power source to a drive unit of the first control valve to close the first control valve; A second power source; a second circuit connected in parallel to the first circuit, the second circuit supplying power from the second power source to a drive unit of the first control valve to close the first control valve; It may further comprise:

[0027] The first circuit supplies power from the first power source to the drive unit of the first control valve. When the temperature of the first cell exceeds a predetermined temperature, the controller supplies power from the first power source to the drive unit of the first control valve through the first circuit. The first control valve closes.

[0028] A secondary battery is mounted, for example, in an automobile and supplies electrical energy to the automobile's traction motor. Cell temperature abnormalities may occur, for example, during an automobile collision. During an automobile collision, the first circuit may not function properly. A temperature control device for a secondary battery is required to have redundancy so that it can supply power to the drive unit of the first control valve to close the first control valve even when the first circuit does not function properly.

[0029] The second circuit is a circuit parallel to the first circuit and supplies power to the drive unit of the first control valve from a second power source separate from the first power source. If the first circuit cannot supply power, the second circuit supplies power to the drive unit of the first control valve, allowing the first control valve to close. This ensures redundancy in the temperature control device for secondary batteries.

[0030] The second power source may include a thermoelectric element attached to the first cell and the second cell, and generating electricity when the temperature of the first cell or the second cell increases.

[0031] When the temperature of the first cell or the second cell rises, an electromotive force is generated in the thermoelectric element due to the Seebeck effect. If the temperature of the first cell or the second cell becomes abnormal, the electromotive force of the thermoelectric element increases, and the second power source including the thermoelectric element can supply enough power to the drive unit of the first control valve to close the first control valve.

[0032] The second power source utilizes the temperature change of the first cell or the second cell, and therefore can stably secure the power to drive the drive unit of the first control valve when it becomes necessary to close the first control valve.

[0033] The secondary battery is mounted on a vehicle, the first power source is a 12V battery; The second power source may be a capacitor on board the vehicle.

[0034] Even if power cannot be supplied from the 12V battery, power can be supplied to the drive unit of the first control valve by using a capacitor installed in the vehicle. For example, the capacitor may be a smoothing capacitor provided in the inverter.

[0035] The second power source may be an emergency power source.

[0036] Even if power cannot be supplied from the first power source, the temperature control device for the secondary battery can use the emergency power source to supply power to the drive unit of the first control valve.

[0037] the second circuit has a switch element that switches between a conductive state in which power from the second power source is supplied to a drive portion of the first control valve and a cut-off state in which the supply of power is cut off, The switch element may be attached to the first cell and the second cell, and may be switched to a conductive state by an electromotive force of a thermoelectric element that generates electricity when the temperature of the first cell or the second cell increases.

[0038] As described above, in a temperature control device for a secondary battery mounted on an automobile, the first circuit does not necessarily function normally, for example, when the automobile crashes.

[0039] The second circuit supplies power from the second power source to the drive unit of the first control valve when the first circuit does not function normally. When the switch element of the second circuit switches from a cut-off state to a conductive state, power is supplied from the second power source to the drive unit of the first control valve.

[0040] The switch element is switched to a conductive state by the electromotive force of the thermoelectric element. Even in the event of a vehicle collision, if the temperature of the first cell or the second cell rises, the switch element can be switched to a conductive state. This increases the reliability of preventing fire from spreading in the temperature control device for the secondary battery.

[0041] The technology disclosed herein relates to a temperature control method for a secondary battery. a refrigerant is caused to flow through a refrigerant passage located between a first main surface of a first cell and a second main surface of a second cell, thereby cooling the first cell through the first main surface and cooling the second cell through the second main surface; When the temperature of the first cell exceeds a predetermined temperature, the refrigerant is discharged from the refrigerant passage through the open / close valve.

[0042] The refrigerant flowing through the refrigerant passages cools the first cells through the first main surface and the second cells through the second main surface, so that the first cells and the second cells are effectively cooled through the large-area first and second main surfaces.

[0043] When an abnormal temperature occurs in the first cell, the on-off valve opens, and the refrigerant is discharged from the refrigerant passage through the open on-off valve. The refrigerant passage between the first cell and the second cell becomes empty, and an air insulation layer is formed between the first cell and the second cell. Due to the high insulation effect of the air insulation layer, even if the gap between the first cell and the second cell is narrow, the transfer of heat from the first cell to the second cell is suppressed, and the rise in the second cell temperature is suppressed. This prevents the secondary battery from burning.

[0044] The temperature control method further comprises: When the temperature of the first cell exceeds a predetermined temperature and before the on-off valve opens, a control valve may receive a control signal from a controller and close the refrigerant passage, thereby stopping the flow of the refrigerant in the refrigerant passage and vaporizing the refrigerant in the refrigerant passage.

[0045] When the temperature of the first cell exceeds a predetermined temperature, the controller closes the refrigerant passage with the control valve. When the refrigerant passage is closed, the flow of refrigerant in the refrigerant passage stops, and the refrigerant in the refrigerant passage receives heat from the first cell and vaporizes (i.e. boils). The first cell is effectively cooled by the boiling cooling of the refrigerant.

[0046] The temperature control method further comprises: When the internal pressure of the refrigerant passage exceeds a predetermined pressure due to evaporation of the refrigerant, the on-off valve may open to open the refrigerant passage.

[0047] After the first cell is cooled by boiling the refrigerant, the on-off valve opens and the refrigerant is discharged from the refrigerant passage. This two-stage measure of boiling the refrigerant and discharging the refrigerant from the refrigerant passage effectively prevents the secondary battery from spreading. [Effects of the Invention]

[0048] According to the temperature control device or temperature control method for a secondary battery, the first cell and the second cell are effectively cooled by flowing a refrigerant through the refrigerant passage between the first cell and the second cell, thereby increasing the energy density of the secondary battery. Furthermore, if an abnormal temperature occurs in a cell, the refrigerant in the refrigerant passage is discharged, and the refrigerant passage forms an air insulating layer, thereby suppressing the spread of fire in the secondary battery. [Brief explanation of the drawings]

[0049] [Figure 1] FIG. 1 shows the basic structure of a temperature control device for a secondary battery. [Figure 2] FIG. 2 shows the detailed structure of the temperature control device for the secondary battery. [Figure 3] FIG. 3 is a block diagram of a temperature control device for a secondary battery. [Figure 4] FIG. 4 illustrates the operation of the temperature control device in the cooling mode. [Figure 5A] FIG. 5A shows the operation of the temperature control device when an abnormality in the cell temperature occurs. [Figure 5B] FIG. 5B shows the operation of the temperature control device when an abnormality in the cell temperature occurs. [Figure 6] FIG. 6 shows the operation of the temperature control device when an abnormal temperature occurs in the third cell. [Figure 7] FIG. 7 shows the operation of the temperature control device in the keep warm mode. [Figure 8] FIG. 8 illustrates the operation of the temperature control device in the warm-up mode. [Figure 9] FIG. 9 shows the operation of the temperature control device in the accelerated warm-up mode. [Figure 10] FIG. 10 shows the operation of the temperature control device when transitioning from the warm-up mode to the cooling mode. [Figure 11] FIG. 11 is a part of a flowchart showing a control procedure of the temperature control device for a secondary battery. [Figure 12] FIG. 12 is a part of a flowchart showing a control procedure of the temperature control device for a secondary battery. [Figure 13] FIG. 13 is a diagram showing a power supply circuit of the temperature control device for a secondary battery. [Figure 14] FIG. 14 is a schematic diagram showing a thermoelectric element attached to a cell. [Figure 15] FIG. 15 shows the relationship between the cell temperature and the power of the second power supply. [Figure 16] FIG. 16 is a diagram showing a power supply circuit according to a modified example. [Figure 17] FIG. 17 is a diagram showing an example of the arrangement of a 12V battery, a capacitor, and an emergency power supply in an automobile. [Figure 18] FIG. 18 is a diagram showing a power supply circuit according to a modified example. [Figure 19] FIG. 19 is a diagram showing a power supply circuit according to a modified example. [Figure 20] FIG. 20 is a diagram showing a power supply circuit according to a modified example. [Figure 21] FIG. 21 is a diagram showing a power supply circuit according to a modified example. [Figure 22] FIG. 22 is a diagram showing a power supply circuit according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0050] Hereinafter, an embodiment of a temperature control device and a temperature control method for a secondary battery will be described with reference to the drawings. The temperature control device and the temperature control method for a secondary battery described here are merely examples.

[0051] (Temperature control device for secondary batteries) FIG. 1 shows a temperature control device 1 for a secondary battery. The secondary battery is mounted on, for example, an automobile. The secondary battery stores electric energy. The secondary battery supplies electric energy to, for example, a traction motor 72 (see FIG. 17). The secondary battery is, for example, a lithium-ion battery.

[0052] The secondary battery includes a plurality of cells 2. The plurality of cells 2 are connected in series. The plurality of cells 2 are lined up in the X direction to form a row. The X direction is a horizontal direction. Note that in FIG. 1, a row of cells is formed by four cells 2 lined up in the X direction, but the number of cells 2 lined up in the X direction is not limited to four. The row of cells 2 is lined up in the Y direction. The Y direction is a horizontal direction and is perpendicular to the X direction. Note that in the secondary battery of FIG. 1, the row of cells 2 is lined up in two rows in the Y direction, but the number of rows of cells 2 lined up in the Y direction is not limited to two.

[0053] The temperature control device 1 includes a cooling circuit 11. The cooling circuit 11 is a circulation circuit that circulates a refrigerant between the cell 2 and a cooler. The cooler cools the refrigerant. The cooler may be, for example, a radiator that cools the refrigerant using the wind generated by the vehicle's movement. The cooler may be, for example, a chiller. The cooler is not limited to a radiator or a chiller. The refrigerant may be, for example, water. The refrigerant may be a low-conductivity LLC (Long Life Coolant) or an air-conditioning refrigerant (such as R-1234yf).

[0054] The cooling circuit 11 has a supply path 12 and a return path 13. The supply path 12 supplies cooled refrigerant from the cooler to the cells 2. The return path 13 returns the refrigerant that has received heat from the cells 2 from the cells 2 to the cooler.

[0055] The cooling circuit 11 also has a refrigerant passage 3. The refrigerant passage 3 is located between adjacent cells 2. The cooling circuit 11 has a plurality of refrigerant passages 3. The refrigerant passages 3 are in contact with the main surfaces 20 of the cells 2. The main surfaces 20 of the cells 2 are surfaces that face each other between adjacent cells 2. The area of ​​the main surfaces 20 is relatively large. Note that a TIM (Thermal Interface Material) may be interposed between the main surfaces 20 of the cells 2 and the refrigerant passages 3.

[0056] The upstream ends of the refrigerant passages 3 are connected to supply passages 12. The cooled refrigerant is distributed from supply passages 12 to the multiple refrigerant passages 3. The downstream ends of the refrigerant passages 3 are connected to return passages 13. The refrigerant that has received heat in the multiple refrigerant passages 3 is collected in return passages 13. Here, supply passage 12 is located above return passages 13. The refrigerant flows from top to bottom in the refrigerant passages 3 (see the diagonal arrows in FIG. 1).

[0057] (Details of the temperature control device) FIG. 2 shows a part of the temperature control device 1 for a secondary battery. FIG. 2 shows one of the columns of cells 2 in FIG. 1. The top of the paper in FIG. 2 corresponds to the top of the temperature control device 1 for a secondary battery, and the bottom of the paper in FIG. 2 corresponds to the bottom of the temperature control device 1 for a secondary battery. The up-down direction of the paper in FIG. 2 corresponds to the vertical direction of the temperature control device 1 for a secondary battery. FIG. 3 is a block diagram of the temperature control device 1 for a secondary battery.

[0058] As shown in FIG. 2, a plurality of cells 2 and a plurality of refrigerant passages 3 are housed in a battery pack 200. Hereinafter, the cells 2 shown in FIG. 2 will be referred to, from right to left, as a first cell 21, a second cell 22, and a third cell 23. The refrigerant passages 3 shown in FIG. 2 will be referred to, from right to left, as a first refrigerant passage 31, a second refrigerant passage 32, and a third refrigerant passage 33. The first refrigerant passage 31 is a refrigerant passage 3 that contacts the main surface of the first cell 21 (i.e., the right main surface in FIG. 2). The second refrigerant passage 32 is a refrigerant passage 3 located between the first cell 21 and the second cell 22, and the second refrigerant passage 32 contacts both the main surface of the first cell 21 and the main surface of the second cell 22. The third refrigerant passage 33 is a refrigerant passage 3 located between the second cell 22 and the third cell 23, and the third refrigerant passage 33 contacts both the main surface of the second cell 22 and the main surface of the third cell 23.

[0059] The cooling circuit 11 has control valves. The control valves open and close the refrigerant passage 3 in response to control signals from a controller 10, which will be described later. The first control valve 41 is located at the downstream end of the first refrigerant passage 31 and opens and closes the first refrigerant passage 31. The second control valve 42 is located at the downstream end of the second refrigerant passage 32 and opens and closes the second refrigerant passage 32. The third control valve 43 is located at the downstream end of the third refrigerant passage 33 and opens and closes the third refrigerant passage 33. As described above, the supply passage 12 is located above the return passage 13, so the first control valve 41 is located at the bottom of the first refrigerant passage 31, the second control valve 42 is located at the bottom of the second refrigerant passage 32, and the third control valve 43 is located at the bottom of the third refrigerant passage 33.

[0060] The cooling circuit 11 has an on-off valve. The on-off valve is a relief valve that opens when the internal pressure of the refrigerant passage exceeds a predetermined pressure. The first on-off valve 44 is located in the battery pack 200 and opens and closes the first refrigerant passage 31. The first on-off valve 44 is located upstream of the first control valve 41 in the first refrigerant passage 31. The second on-off valve 45 is located in the battery pack 200 and opens and closes the second refrigerant passage 32. The second on-off valve 45 is located upstream of the second control valve 42 in the second refrigerant passage 32. The third on-off valve 46 is located in the battery pack 200 and opens and closes the third refrigerant passage 33. The third on-off valve 46 is located upstream of the third control valve 43 in the third refrigerant passage 33.

[0061] In FIG. 2, the refrigerant passage 3 is shown as a first refrigerant passage 31, a second refrigerant passage 32, and a third refrigerant passage 33, but the cooling circuit 11 has the above-mentioned control valve and on-off valve for each refrigerant passage 3.

[0062] The cooling circuit 11 has a first open valve 47. The first open valve 47 is located in the supply path 12. When the first open valve 47 is opened, the supply path 12 is opened to the atmosphere. The first open valve 47 switches between an open state and a closed state in response to a control signal from the controller 10.

[0063] The cooling circuit 11 has a second open valve 48. The second open valve 48 is located in the return path 13. When the second open valve 48 opens, the return path 13 is opened to the atmosphere. The second open valve 48 is, for example, an on-off valve having a ball (float) therein that floats on the refrigerant. As will be described later, when the refrigerant in the return path 13 is discharged and the return path 13 is empty, the second open valve 48 opens. When the return path 13 is filled with refrigerant, the ball floats up, causing the second open valve 48 to close. The second open valve 48 has an airflow sensor 49. The airflow sensor 49 detects that air is being discharged from the return path 13 through the open second open valve 48. A detection signal from the airflow sensor 49 is output to the controller 10. Based on the detection signal from the airflow sensor 49, the controller 10 can determine that the empty return path 13 has been filled with refrigerant.

[0064] 3, the cooling circuit 11 has a first pump 51. The first pump 51 is located in the supply path 12 or the return path 13. The first pump 51 is, for example, an electric pump. When the first pump 51 is driven, the refrigerant circulates between the cooler and the cell 2 through the supply path 12 and the return path 13.

[0065] The temperature control device 1 for a secondary battery has a bypass circuit 14. The bypass circuit 14 is a circuit that bypasses the cooler. The bypass circuit 14 has a first bypass path 15, a second bypass path 16, and a tank 17. The first bypass path 15 connects the supply path 12 and the tank 17. The first bypass path 15 is connected to the supply path 12 via a first three-way valve 18. The first three-way valve 18 switches between a position where the cooler communicates with the cell 2 and where the bypass circuit 14 is blocked (see FIG. 4), a position where the cooler communicates with the cell 2 (a position where the cooler communicates with the bypass circuit 14, see FIG. 6), and a position where the bypass circuit 14 communicates with the cell 2 and where the cooler is blocked (see FIG. 9). The first three-way valve 18 changes its position in response to a control signal from the controller 10. The first three-way valve 18 is an example of a shutoff valve.

[0066] A second pump 52 is provided in the first bypass path 15. The second pump 52 is, for example, an electric pump. When the second pump 52 is driven, as will be described later, the refrigerant is supplied from the tank 17 to the supply path 12. The controller 10 outputs a control signal to the second pump 52, and the second pump 52 switches between driving and stopping in response to the control signal from the controller 10.

[0067] The second bypass line 16 connects the return line 13 and the tank 17. The second bypass line 16 is connected to the return line 13 via a second three-way valve 19. The second three-way valve 19 switches between a position where the cooler communicates with the cell 2 and where the bypass circuit 14 is blocked (see FIG. 4), a position where the bypass circuit 14 communicates with the cooler and where the cell 2 is blocked (see FIG. 7), and a position where the bypass circuit 14 communicates with the cell 2 and where the cooler is blocked (see FIG. 8). The second three-way valve 19 changes its position in response to a control signal from the controller 10.

[0068] As will be described later, the tank 17 stores the refrigerant discharged from the refrigerant passage 3. The tank 17 is located at a position lower than the supply path 12 in the vertical direction in the temperature control device 1 for a secondary battery. The tank 17 has a tank valve 171. The tank valve 171 is interposed between the tank 17 and the first bypass path 15. When the tank valve 171 is opened, the refrigerant in the tank 17 is supplied to the supply path 12 through the first bypass path 15.

[0069] Tank 17 also has a third open valve 172. Third open valve 172 opens the inside of tank 17 to the atmosphere. When the inside of tank 17 is opened to the atmosphere, the discharge of refrigerant from refrigerant passage 3 to tank 17 is promoted, as will be described later.

[0070] The tank 17 has a heater 173. The heater 173 is, for example, an electric heater. The heater 173 heats the refrigerant stored in the tank 17. The heating by the heater 173 increases the temperature of the refrigerant.

[0071] 3, the temperature control device 1 for a secondary battery has a refrigerant temperature sensor 53. The refrigerant temperature sensor 53 outputs a measurement signal corresponding to the temperature of the refrigerant to the controller 10. The temperature control device 1 for a secondary battery also has an outside air temperature sensor 54. The outside air temperature sensor 54 outputs a measurement signal corresponding to the outside air temperature to the controller 10.

[0072] Each cell 2 has a thermistor. The thermistor outputs a measurement signal corresponding to the temperature of the cell 2 to the controller 10. In Figure 3, the first cell 21 has a first thermistor 210, the second cell 22 has a second thermistor 220, and the third cell 23 has a third thermistor 230. The controller 10 can determine the temperature of each individual cell 2.

[0073] (Operation of temperature control device for secondary battery) Next, the operation of the temperature control device 1 for a secondary battery will be described with reference to the drawings.

[0074] (Cooling mode (normal)) 4 shows the operation of the temperature control device 1 in a cooling mode in which the cell 2 is cooled. The cooling mode corresponds to normal driving of the automobile. In the cooling mode, the first three-way valve 18 and the second three-way valve 19 communicate with the cooler and the cell 2 in response to a control signal from the controller 10 (i.e., the three-way valves are in the open position). The first control valve 41, the second control valve 42, and the third control valve 43 are all open in response to a control signal from the controller 10. The first release valve 47 is closed in response to a control signal from the controller 10, and the second release valve 48 is closed because the return line 13 is filled with refrigerant.

[0075] The refrigerant cooled by the cooler passes from the supply path 12 through the first refrigerant passage 31, the second refrigerant passage 32, and the third refrigerant passage 33 by the drive of the first pump 51. The first cell 21, the second cell 22, and the third cell 23 are cooled. The refrigerant that has passed through the first refrigerant passage 31, the second refrigerant passage 32, and the third refrigerant passage 33 returns to the cooler through the return path 13. The refrigerant circulates through the cooling circuit 11.

[0076] In the cooling mode, the bypass circuit 14 is separated from the cooling circuit 11. The tank valve 171 is closed in response to a control signal from the controller 10, and the second pump 52 is stopped. The third release valve 172 is also closed.

[0077] (When abnormal temperature occurs) 5A and 5B show the operation of the temperature control device 1 when a temperature abnormality occurs in one cell 2 (i.e., abnormality occurrence mode). FIGS. 5A and 5B show an example in which the temperature of the second cell 22 exceeds a first predetermined temperature. If the controller 10 determines, based on a signal from the second thermistor 220, that the temperature of the second cell 22 exceeds the first predetermined temperature, it closes the second control valve 42 in the second refrigerant passage 32 that contacts the main surface of the second cell 22 and the third control valve 43 in the third refrigerant passage 33. The flow of refrigerant through the second refrigerant passage 32 and the third refrigerant passage 33 stops (see the upper diagram in FIG. 5A). The controller 10 keeps the first control valve 41 open in the first refrigerant passage 31 that does not contact the second cell 22. The refrigerant continues to circulate in the cooling circuit 11. The circulating refrigerant continues to cool the first cell 21.

[0078] After the second control valve 42 and the third control valve 43 are closed, the refrigerant in the second refrigerant passage 32 and the third refrigerant passage 33 receives heat from the second cell 22 and boils (see the lower diagram in FIG. 5A). The refrigerant boils and cools in the second refrigerant passage 32 and the third refrigerant passage 33 adjacent to the second cell 22, effectively cooling the high-temperature second cell 22 from both sides. Transfer of heat from the second cell 22 to the first cell 21 or the third cell 23 is suppressed, thereby suppressing the secondary battery from spreading fire.

[0079] As the refrigerant in the second refrigerant passage 32 and the third refrigerant passage 33 evaporates, the internal pressure of the second refrigerant passage 32 and the third refrigerant passage 33 increases, causing the second on-off valve 45 and the third on-off valve 46 to open. The evaporated refrigerant is discharged from the second refrigerant passage 32 and the third refrigerant passage 33 through the second on-off valve 45 and the third on-off valve 46 into the battery pack 200 (see the white arrows in the lower diagram of FIG. 5A). The battery pack 200 has an air vent valve 201. As the internal pressure of the battery pack 200 increases, the air vent valve 201 opens. The evaporated refrigerant is discharged to the outside of the battery pack 200 (see the black arrows in the lower diagram of FIG. 5A).

[0080] After the second control valve 42 and the third control valve 43 are closed, if the temperature of the second cell 22 exceeds a second predetermined temperature (where the second predetermined temperature is greater than the first predetermined temperature), the controller 10 switches the position of the first three-way valve 18 to a position that blocks the connection between the cooler and the cell 2 (i.e., the first three-way valve 18 is closed), as shown in FIG. 5B. The first pump 51 is stopped. The refrigerant (including vaporized refrigerant) in the supply path 12 and the refrigerant passage 3 is discharged through the second on-off valve 45 and the third on-off valve 46. The controller 10 also opens the first open valve 47. The opening of the first open valve 47 applies atmospheric pressure to the supply path 12 and the refrigerant passage 3. Discharge of the refrigerant through the second on-off valve 45 and the third on-off valve 46 is promoted.

[0081] The second refrigerant passage 32 and the third refrigerant passage 33 become empty. The second refrigerant passage 32 and the third refrigerant passage 33 adjacent to the main surface of the second cell 22 with the abnormal temperature function as an air insulating layer. The air insulating layer has a high insulating effect, so the heat of the second cell 22 is prevented from being transferred to the first cell 21 or the third cell 23. This prevents the secondary battery from spreading.

[0082] The temperature control device 1 for a secondary battery can effectively cool a cell 2 (here, the second cell 22) that has become abnormally hot by evaporating the refrigerant in the refrigerant passage 3. The cell 2 is effectively cooled by the refrigerant passages 3 on both sides. If the temperature of the cell 2 does not drop even after evaporating the refrigerant, the refrigerant passage 3 is made into an air insulating layer to prevent the spread of fire. The temperature control device 1 for a secondary battery can effectively prevent the spread of fire by taking two-stage measures.

[0083] In the temperature control device 1 for a secondary battery, the refrigerant passage 3 is located between the main surfaces 20 of the cells 2, so that the cells 2 can be effectively cooled by the cooled refrigerant. Effective cooling of the cells 2 by the refrigerant passage 3 enables rapid charging of the secondary battery. In addition, effective cooling of the cells 2 allows the spacing between the cells 2 to be narrowed. Reducing the spacing between the cells 2 is advantageous for improving the energy density of the secondary battery.

[0084] If the spacing between the cells 2 is narrow, there is a risk of fire spreading if a temperature abnormality occurs in the cells 2. However, the temperature control device 1 for a secondary battery described above can make the refrigerant passages 3 on both sides of the cell 2 where a temperature abnormality occurs function as air insulation layers. Because the air insulation layer has a high insulating effect, heat transfer from cell 2 to cell 2 is suppressed even if the spacing between the cells 2 is narrow. As a result, fire spreading in the secondary battery is suppressed.

[0085] The temperature control device 1 for a secondary battery can improve the cooling efficiency of the secondary battery, improve the energy density, and prevent the spread of fire.

[0086] 6 shows the operation of the temperature control device 1 for a secondary battery when a temperature abnormality occurs in the third cell 23. When a temperature abnormality occurs in the third cell 23, the third control valve 43 in the third refrigerant passage 33 adjacent to the main surface of the third cell 23 is closed by the controller 10. The second control valve 42 in the second refrigerant passage 32 not adjacent to the main surface of the third cell 23 and the first control valve 41 in the first refrigerant passage 31 both remain open. As the refrigerant flows through the second refrigerant passage 32 and the first refrigerant passage 31, the second cell 22 and the first cell 21 are cooled, respectively.

[0087] (Keep warm mode) Figure 7 shows the operation of the temperature control device 1 for a secondary battery in the keep warm mode. The keep warm mode is a mode used when the temperature of the refrigerant is higher than the temperature of the cell 2 and the outside air temperature is lower than a predetermined temperature (for example, 5°C). Because the temperature of the cell 2 is relatively low and the outside air temperature is low, the refrigerant surrounding the cell 2 keeps the cell 2 warm so that the temperature rise of the cell 2 is not inhibited by the low temperature outside air. As the secondary battery is charged and discharged while the vehicle is running, the temperature of the cell 2 rises due to the heat generated by the cell 2 itself.

[0088] Specifically, in the heat retention mode, the controller 10 switches the positions of the first three-way valve 18 and the second three-way valve 19 to positions that block the cooler from the cell 2 (i.e., the three-way valves are closed). The first pump 51 is also stopped. Refrigerant does not circulate in the cooling circuit 11. Because the temperature of the refrigerant is higher than the temperature of the cell 2, heat is not transferred from the cell 2 to the refrigerant, and heat transfer between the cell 2 and the outside air is also suppressed. Cooling of the cell 2 by the low-temperature outside air is suppressed. The temperature of the cell 2 quickly rises to an appropriate temperature.

[0089] (Warm-up mode) 8 shows the operation of the temperature control device 1 for a secondary battery in warm-up mode. The warm-up mode is a mode in which the temperature of the refrigerant is lower than or equal to the temperature of the cell 2, and the temperature of the cell 2 is below a predetermined temperature (e.g., 10°C). Because the temperature of the cell 2 is low, it is desirable to increase the temperature of the cell 2. However, because the temperature of the refrigerant is also low, even if the cell 2 generates heat, heat will be transferred from the cell 2 to the refrigerant. Therefore, during warm-up, the refrigerant passage 3 around the cell 2 is emptied to suppress the transfer of heat from the cell 2 to the refrigerant.

[0090] Specifically, the controller 10 switches the position of the first three-way valve 18 to a position that blocks the cooler from the cell 2. The controller 10 also stops the first pump 51. The controller 10 switches the second three-way valve 19 to connect the cell 2 to the tank 17 and block the cooler (i.e., the drain position of the second three-way valve 19). No refrigerant circulates in the cooling circuit 11.

[0091] The controller 10 opens the first open valve 47. Atmospheric pressure acts on the supply path 12, the refrigerant passage 3, part of the return path 13, and the tank 17. The controller 10 also opens the third open valve 172. The refrigerant from the supply path 12 downstream of the first three-way valve 18 to the return path 13 upstream of the second three-way valve 19 flows through the second bypass path 16 to the tank 17, which is located at a lower position in the vertical direction. The tank 17 stores the refrigerant. The tank valve 171 is closed.

[0092] Since the refrigerant passages 3 around the cells 2 are empty, heat radiation from the cells 2 is suppressed when the temperature of the cells 2 rises. The temperature of the cells 2 rises quickly.

[0093] (Accelerated warm-up mode) 8 and 9 show the operation of the temperature control device 1 for a secondary battery in the accelerated warm-up mode. Similar to the warm-up mode, the accelerated warm-up mode is a mode in which the temperature of the refrigerant is lower than or equal to the temperature of the cells 2, and the temperature of the cells 2 is equal to or lower than a predetermined temperature (e.g., 10°C). Unlike the warm-up mode, the accelerated warm-up mode uses the heater 173 in the tank 17 to heat the refrigerant.

[0094] In the accelerated warm-up mode, the temperature control device 1 for a secondary battery energizes the heater 173. As shown in FIG. 8, the refrigerant stored in the tank 17 is heated by the heater 173. When the temperature of the refrigerant in the tank 17 rises, as shown in FIG. 9, the controller 10 switches the position of the first three-way valve 18 to a position where the tank 17 and the cell 2 communicate with each other (i.e., the water supply position of the first three-way valve 18). The controller 10 also closes the first open valve 47. Note that the controller 10 may switch the position of the first three-way valve 18 to a position where the tank 17 and the cell 2 communicate with each other and close the first open valve 47 without waiting for the temperature of the refrigerant in the tank 17 to rise.

[0095] The controller 10 also opens the tank valve 171 to drive the second pump 52. The heated refrigerant in the tank 17 is supplied to the supply path 12 through the first bypass path 15. The heated refrigerant promotes a temperature increase in the cells 2 while passing through the refrigerant path 3. The refrigerant that has passed through the refrigerant path 3 returns to the tank 17 through the second bypass path 16. While the heater 173 continues to be energized, the refrigerant circulates through part of the cooling circuit 11 and the bypass circuit 14, promoting the warming up of the cells 2.

[0096] Note that, when the state in which the refrigerant passage 3 is empty shown in FIG. 8 shifts to the state in which the refrigerant passage 3 is filled with refrigerant shown in FIG. 9, the third open valve 172 of the tank 17 may be closed.

[0097] (Transition from warm-up mode to cooling mode) Fig. 10 shows the operation of the temperature control device 1 for a secondary battery when transitioning from warm-up mode to cooling mode. When warm-up is performed when the cells 2 are at low temperatures, the refrigerant passages 3 are empty to suppress heat dissipation from the cells 2, as shown in Fig. 8. When the temperature of the cells 2 rises and cooling of the cells 2 is required, the refrigerant passages 3 must be filled with refrigerant.

[0098] The controller 10 first switches the position of the first three-way valve 18 to a position that connects the tank 17 and the cell 2, and closes the first open valve 47. The controller 10 also switches the position of the second three-way valve 19 to a position that connects the tank 17 and the cooler, and shuts off the cell 2. In this state, the controller 10 opens the tank valve 171 and drives the second pump 52. Refrigerant in the tank 17 is supplied to the supply path 12 through the first bypass path 15. As described above, the second open valve 48 opens when the return path 13 is empty. Refrigerant is charged from the supply path 12 located above through the refrigerant passage 3 into the return path 13 located below. When the return path 13 is charged with refrigerant, the second open valve 48 closes. The controller 10 determines that the second open valve 48 has switched from an open state to a closed state based on a detection signal from the airflow sensor 49. While the airflow sensor 49 is measuring the airflow through the second release valve 48, the controller 10 determines that the second release valve 48 is in an open state. When the airflow sensor 49 stops measuring the airflow through the second release valve 48, the controller 10 determines that the second release valve 48 has transitioned from an open state to a closed state. When the second release valve 48 closes, the controller 10 determines that the supply path 12, the refrigerant passage 3, and the return path 13 have been filled with refrigerant, and switches the second three-way valve 19 to a position that connects the cooler to the cell 2. The controller 10 also switches the first three-way valve 18 to a position that connects the cooler to the cell 2, closes the tank valve 171, and stops the second pump 52. The temperature control device 1 for a secondary battery transitions to operation in the cooling mode shown in FIG. 4.

[0099] (Control procedure for temperature control device for secondary battery) Next, the control procedure of the temperature control device 1 for a secondary battery will be described with reference to FIGS.

[0100] First, in step S11 after starting, the controller 10 acquires various sensor values. The sensor values ​​include the measurement value of the thermistor of the cell 2, the measurement value of the air flow sensor 49, the measurement value of the refrigerant temperature sensor 53, and the measurement value of the outside air temperature sensor 54.

[0101] In the next step S12, the controller 10 determines the operation mode of the secondary battery temperature control device 1 based on the sensor value acquired in step S11. The operation modes include the cooling mode, heat retention mode, warm-up mode, and accelerated warm-up mode, as well as an abnormality occurrence mode when an abnormality in the temperature of the cell 2 occurs.

[0102] If the controller 10 determines that the system is in the abnormality occurrence mode, i.e., if the temperature of any cell 2 exceeds a first predetermined temperature T1, the process proceeds from step S13 to step S21 in FIG. 12. If the controller 10 determines that the system is in the keep-warm mode (i.e., if the refrigerant temperature is higher than the cell 2 temperature and the outside air temperature is lower than a predetermined temperature (e.g., 5°C)), the process proceeds from step S14 to step S24 in FIG. 12. If the controller 10 determines that the system is in the warm-up mode (i.e., if the refrigerant temperature is lower than or equal to the cell 2 temperature and the cell 2 temperature is equal to or lower than a predetermined temperature (e.g., 10°C)), the process proceeds from step S15 to step S25 in FIG. 12. If the controller 10 determines that the system is in the accelerated warm-up mode (i.e., if the refrigerant temperature is lower than or equal to the cell 2 temperature and the cell 2 temperature is equal to or lower than a predetermined temperature (e.g., 10°C)), the process proceeds from step S16 to step S25 in FIG. 12. If the controller 10 determines that the mode is cooling, the process proceeds from step S17 to step S211 in FIG.

[0103] In the flow abnormality occurrence mode of FIG. 12, in step S21, the controller 10 closes the control valve of the refrigerant passage 3 adjacent to the cell 2 with the temperature abnormality. The flow of refrigerant in the refrigerant passage 3 stops. The refrigerant in the refrigerant passage 3 receives heat from the cell 2 and vaporizes (see FIG. 5A). The cell 2 is effectively cooled by boiling cooling.

[0104] In the next step S22, the controller 10 determines whether the temperature of the abnormal cell 2 exceeds a second predetermined temperature (T2). If the temperature of cell 2 does not exceed the second predetermined temperature, the process returns to start. If the temperature of cell 2 exceeds the second predetermined temperature, the controller 10 closes the first three-way valve 18 in step S23. That is, as shown in FIG. 5B or 6, the controller 10 positions the first three-way valve 18 to connect the cooler and the tank 17 and to block the cell 2. The controller 10 also opens the first open valve 47. This promotes the discharge of the refrigerant from the refrigerant passage 3. Because the refrigerant passage 3 is empty, the risk of the secondary battery catching fire is reduced.

[0105] In the heat retention mode of the flow of FIG. 12, the controller 10 closes the first three-way valve 18 and the second three-way valve 19 in step S24. That is, as shown in FIG. 7, the first three-way valve 18 is positioned to connect the cooler and the tank 17 and to block the cell 2. The second three-way valve 19 is positioned to connect the cooler and the tank 17 and to block the cell 2. The flow of refrigerant in the cooling circuit 11 stops, and the cell 2 is kept warm by the refrigerant in the refrigerant passage 3, which has a relatively high temperature.

[0106] In the warm-up mode or accelerated warm-up mode of the flow of FIG. 12, the controller 10 closes the first three-way valve 18 and sets the second three-way valve to the drain position in step S25. That is, as shown in FIG. 8, the first three-way valve 18 is positioned to connect the cooler and the tank 17 and to block the cell 2. The second three-way valve 19 is positioned to connect the cell 2 and the tank 17 and to block the cooler. In the following step S26, the controller 10 opens the first open valve 47 and the third open valve 172. The refrigerant in the supply path 12 and the refrigerant passage 3 is discharged to the tank 17, and the refrigerant passage 3 becomes empty.

[0107] In the accelerated warm-up mode, the process further proceeds from step S27 to step S28. In step S28, the controller 10 turns on the heater 173, and then in step S29, switches the first three-way valve 18 to the water supply position. As shown in FIG. 9, the first three-way valve 18 is switched to a position where the tank 17 and the cell 2 are in communication and the cooler is shut off. Then, in step S210, the controller 10 turns on the second pump 52. The refrigerant warmed by the heater 173 in the tank 17 circulates through part of the cooling circuit 11 and the bypass circuit 14. The cell 2 is warmed by the refrigerant.

[0108] In the cooling mode of the flow shown in FIG. 12, the controller 10 transitions from the warm-up mode to the cooling mode in steps S211 to S213. Specifically, in step S211, the controller 10 sets the first three-way valve 18 to the water supply position and closes the second three-way valve 19. As shown in FIG. 10, the first three-way valve 18 is positioned to connect the tank 17 and the cell 2 and to block the cooler. The second three-way valve 19 is positioned to connect the tank 17 and the cooler and to block the cell 2. In the following step S212, the controller 10 drives the second pump 52 to supply the refrigerant from the tank 17 from the supply path 12 to the refrigerant passage 3. Then, in step S213, the controller 10 determines whether the air flow VAFS through the second open valve 48 is zero based on the measurement signal of the airflow sensor 49. If the VAFS is not zero, the second open valve 48 is open, and the supply path 12 and the refrigerant passage 3 are not filled with refrigerant, so the controller 10 continues steps S211 and S212. If the determination in step S213 is Yes, the supply path 12 and the refrigerant passage 3 are filled with refrigerant, so the controller 10 stops the second pump 52 in step S214 and opens the first three-way valve 18 and the second three-way valve 19 in step S215. That is, as shown in FIG. 4 , the first three-way valve 18 connects the cooler and the cell 2, and the second three-way valve 19 connects the cooler and the cell 2. The controller 10 turns on the first pump 51 in step S216, causing refrigerant to circulate in the cooling circuit 11, and the cooled refrigerant cools the cell 2.

[0109] (Modifications regarding opening and closing of the on-off valve) In the temperature control device 1 and temperature control method for a secondary battery described above, after the refrigerant in the refrigerant passage 3 is vaporized, the on-off valve is opened to discharge the refrigerant from the refrigerant passage 3. In the temperature control device 1 and temperature control method for a secondary battery, the on-off valve may be forcibly opened to discharge the refrigerant from the refrigerant passage 3 without the refrigerant being vaporized. The on-off valve may be a control valve that opens and closes in response to a control signal from the controller 10.

[0110] (Power supply circuit for temperature control device for secondary batteries) FIG. 13 shows the power supply circuit 6 of the temperature control device 1 for a secondary battery. The power supply circuit 6 supplies power to the actuator 30 of the control valve 41, 42, or 43 described above. The actuator 30 is a drive unit that opens and closes the control valve 41, 42, or 43. The actuator 30 is, for example, an electric motor. As described above, the control valve 41, 42, or 43 closes the refrigerant passage 31, 32, or 33 corresponding to the cell 21, 22, or 23 that has experienced an abnormal temperature. Therefore, the temperature control device 1 for a secondary battery has the power supply circuit 6 of FIG. 13 corresponding to each control valve 41, 42, or 43.

[0111] The power supply circuit 6 includes a first circuit 61 and a second circuit 62. The first circuit 61 and the second circuit 62 are parallel to the actuator 30. The first circuit 61 and the second circuit 62 make the power supply circuit 6 redundant.

[0112] The first circuit 61 has a first power supply 611. The first power supply 611 is a 12V battery installed in the automobile (see also FIG. 17).

[0113] The first circuit 61 has a first switch element 612. The first switch element 612 is located between the first power supply 611 and the actuator 30. The first switch element 612 is a transistor. The base of the first switch element 612 is connected to the controller 10. The controller 10 outputs a control signal to the first switch element 612 to switch the first switch element 612 between a conductive state and a cut-off state.

[0114] The second circuit 62 has a second power source 621. The second power source 621 includes a thermoelectric element 63. The thermoelectric element 63 is attached to the surface of the cell 2, for example, as shown in FIG. 14. A plurality of thermoelectric elements 63 are attached to each cell 2. The second power source 621 is configured by connecting the plurality of thermoelectric elements 63 in series. When the temperature of the cell 2 increases, a temperature difference occurs in the thermoelectric element 63, generating an electromotive force. FIG. 15 shows the relationship between the temperature of the cell 2 and the voltage of the second power source 621 including the thermoelectric element 63. When the temperature of the cell 2 increases, the power generation voltage of each thermoelectric element 63 increases, and therefore the voltage of the second power source 621 increases.

[0115] The second circuit 62 has a second switch element 622. The second switch element 622 is located between the second power supply 621 and the actuator 30. The second switch element 622 is a transistor.

[0116] The second circuit 62 has a voltage-divider circuit 623. The voltage-divider circuit 623 is connected to a second power supply 621. The voltage-divider circuit 623 has a first resistor 624 and a second resistor 625. The output of the voltage-divider circuit 623 is input to the base of a second switch element 622. As shown in FIG. 15 , when the temperature of cell 2 reaches T, the voltage of the second power supply 621 becomes V. When the voltage of the second power supply 621 becomes V, the second switch element 622 switches from a cutoff state to a conduction state via the voltage-divider circuit 623. By appropriately setting the resistance values ​​of the first resistor 624 and the second resistor 625, the temperature T of cell 2 at which the second switch element 622 switches from a cutoff state to a conduction state can be made to correspond to the temperature abnormality described above.

[0117] As described above, when the temperature of the cell 21, 22, or 23 exceeds the first predetermined temperature, the controller 10 switches the first switch element 612 from the cut-off state to the conductive state. Electric power is supplied from the first power source 611 to the actuator 30 of the control valve 41, 42, or 43 corresponding to the cell 21, 22, or 23 through the first circuit 61. As a result, the control valve 41, 42, or 43 closes.

[0118] The above-mentioned temperature abnormality of cell 2 may occur, for example, during a vehicle collision. During a vehicle collision, the first circuit 61 may not function properly. For example, a vehicle collision may cause a short circuit in the first power source 611, which is a 12V battery. The temperature control device 1 for a secondary battery is required to have redundancy so that power for closing the control valve 41, 42, or 43 is supplied to the actuator 30 of the control valve 41, 42, or 43 even when the first circuit 61 does not function properly.

[0119] The second circuit 62 supplies power to the actuator 30 of the control valve 41, 42, or 43 from a second power source 621, which is parallel to the first circuit 61 and separate from the first power source 611. Even when the first circuit 61 cannot supply power, the second circuit 62 supplies power to the actuator 30 of the control valve 41, 42, or 43, allowing the control valve 41, 42, or 43 to close. Closing the control valve 41, 42, or 43 causes the refrigerant to evaporate in the refrigerant passage 31, 32, or 33 corresponding to the cell 21, 22, or 23 with an abnormal temperature, thereby effectively cooling the cell 21, 22, or 23. The temperature control device 1 for a secondary battery can ensure redundancy.

[0120] Furthermore, since the second power source 621 of the second circuit 62 includes the thermoelectric element 63 attached to the cell 2, when the temperature of the cell 21, 22, or 23 rises, the second power source 621 can ensure an electromotive force that can be supplied to the actuator 30 of the control valve 41, 42, or 43. The second power source 621 can stably ensure the power to drive the actuator 30 when it becomes necessary to close the control valve 41, 42, or 43.

[0121] Furthermore, since the second circuit 62 has the voltage dividing circuit 623, when the temperature of the cell 21, 22, or 23 exceeds the first predetermined temperature and it becomes necessary to close the control valve 41, 42, or 43, the second switch element 622 is turned on, and power is supplied to the actuator 30 of the control valve 41, 42, or 43. The second circuit 62, which is not controlled by the controller 10, can stably supply power to the actuator 30 of the control valve 41, 42, or 43 even in the event of a vehicle collision. This increases the reliability of fire spread prevention in the temperature control device 1 for a secondary battery.

[0122] (Modification of power supply circuit) 16 shows a power supply circuit 60 according to a modification. The power supply circuit 60 differs from the second circuit 62 of the power supply circuit 6 in the configuration of a second circuit 620.

[0123] The second circuit 620 has a capacitor as the second power supply 626. For example, as shown in FIG. 17 , the capacitor may be a smoothing capacitor included in the inverter 71. The inverter 71 uses power from the battery pack 200 to drive a traction motor 72 of the vehicle. The traction motor 72 is disposed, for example, in a motor compartment of the vehicle, and the inverter 71 is disposed close to the traction motor 72. The inverter 71 is less susceptible to damage in the event of a vehicle collision. The second power supply 626, which uses a smoothing capacitor within the inverter 71, is less likely to be lost in the event of a vehicle collision than the first power supply 611, which is a 12V battery. Note that the capacitor constituting the second power supply 626 is not limited to the smoothing capacitor of the inverter 71. An appropriate capacitor installed in the vehicle can be used as the second power supply 626.

[0124] The second circuit 620 also includes one thermoelectric element 63 or multiple thermoelectric elements 63 connected in series. The thermoelectric element 63 is connected to the base of a second switch element 622. As shown in FIG. 14, the thermoelectric element 63 is attached to the surface of the cell 2. When the temperature of the cell 21, 22, or 23 becomes abnormal, an electromotive force is generated in the thermoelectric element 63, and the second switch element 622 switches from a cut-off state to a conduction state. The second circuit 620 supplies power from a second power source 626 to the actuator 30 of the control valve 41, 42, or 43. In the second circuit 620, the thermoelectric element 63 switches the second switch element 622 from a cut-off state to a conduction state without intervention of the controller 10, thereby improving the reliability of preventing fire from spreading in the temperature control device 1 for a secondary battery.

[0125] Fig. 18 shows a modification of the power supply circuit 60 in Fig. 16. The power supply circuit 60a has a voltage-driven NMOS transistor 631. A thermoelectric element 63 is connected to the gate of the NMOS transistor 631. When the temperature of the cell 21, 22, or 23 becomes abnormal, the thermoelectric element 63 turns on the NMOS transistor 631.

[0126] The power supply circuit 60a has a voltage dividing circuit 632. The output of the dividing circuit 632 is input to the base of the second switch element 622. When the NMOS transistor 631 is turned on, the second switch element 622 is switched from a cut-off state to a conductive state using power from the second power supply 626.

[0127] The power supply circuit 60a further includes a power supply circuit 633. The power supply circuit 633 drops the voltage of a second power supply 626 made up of a capacitor and supplies the voltage to the actuator 30. The power supply circuit 633 enables the actuator, which is normally driven by a first power supply 611 made up of a 12V battery, to be driven by the second power supply 626. The power supply circuit 633 may be, for example, an isolated switching power supply. Alternatively, the power supply circuit 633 may be a non-isolated switching power supply. Alternatively, the power supply circuit 633 may be a linear power supply.

[0128] Figure 19 shows a modification of the power supply circuit 60a in Figure 18. The power supply circuit 60b has a voltage dividing resistor 634 between the thermoelectric element 63 and the NMOS transistor 631. By appropriately setting the resistance value of the voltage dividing resistor 634, it is possible to adjust the relationship between the output voltage of the thermoelectric element 63 and the voltage at which the NMOS transistor 631 turns on.

[0129] Figure 20 shows a modification of the power supply circuit 60a in Figure 18. The power supply circuit 60c uses a voltage dividing resistor 635 instead of the power supply circuit 633 to drop the voltage of the second power supply 626. However, with this configuration, the voltage value is affected by the current consumption of the actuator 30. When the actuator 30 changes from a stopped state to an operating state, the applied voltage to the actuator 30 drops.

[0130] 16, 18, 19, and 20, the actuator 30, the power supply circuit 633, or the voltage dividing resistor 635 can also be a heat source. If it is desired to prevent the thermoelectric element 63 from being affected by the power generation of these devices, the thermoelectric element 63 can be arranged away from these devices. If it is desired to actively affect the thermoelectric element 63 with the power generation of these devices, the thermoelectric element 63 can be arranged close to these devices.

[0131] 21 shows a power supply circuit 600 according to a modification. In the power supply circuit 600, the configuration of a second circuit 6200 differs from the second circuit 62 of the power supply circuit 6 and the second circuit 620 of the power supply circuit 60.

[0132] Second power supply 627 of second circuit 6200 is an emergency power supply. Second power supply 627, which is an emergency power supply, may be housed in battery pack 200, for example, as shown imaginarily in Fig. 17. This is because the inside of battery pack 200 is less likely to be damaged even in the event of a car collision.

[0133] The second power source 627, which is an emergency power source, may be a secondary battery that can be charged and discharged. The second circuit 6200 has a DC / DC converter 628. The DC / DC converter 628 is interposed between the thermoelectric element 63 and the second power source 627. The thermoelectric element 63 is attached to the surface of the cell 2, as shown in FIG. 14. When the temperature of the cell 2 rises and an electromotive force is generated in the thermoelectric element 63, the second power source 627 is charged through the DC / DC converter 628. In other words, the second power source 627 is charged by the thermoelectric element 63 during normal driving of the automobile, etc.

[0134] If the temperature of the cell 21, 22, or 23 becomes abnormal, as described above, the second switch element 622 is switched from the cut-off state to the conduction state by the thermoelectric element 63. Electric power is supplied from the second power source 627 to the actuator 30 of the control valve 41, 42, or 43.

[0135] 22 shows a power supply circuit 6000 according to a modified example. The power supply circuit 6000 has two second circuits 62a, 62b. The second circuit 62a includes a second power source 621a formed by a thermoelectric element 63 attached to the second cell 22, for example, and is a circuit that drives the actuator 30 of the second control valve 42 in the second refrigerant passage 32 corresponding to the second cell 22. The second circuit 62b is a circuit that includes a second power source 621b formed by a thermoelectric element 63 attached to the first cell 21 adjacent to the second refrigerant passage 32.

[0136] In the power supply circuit 6000, if the second cell 22 experiences a temperature abnormality, the voltage of the second power source 621a increases, causing the second circuit 62a to close the second refrigerant passage 32 via the actuator 30 of the second control valve 42. If the first cell 21 experiences a temperature abnormality, the voltage of the second power source 621b increases, causing the second circuit 62b to close the second refrigerant passage 32 via the actuator 30 of the second control valve 42. The power supply circuit 6000 can close a specific refrigerant passage 3 in response to temperature abnormalities in two adjacent cells 2 on both sides of that refrigerant passage 3.

[0137] 16, 18 to 20 can also be modified as shown in Fig. 22. Similarly, the power supply circuit 600 in Fig. 21 can also be modified as shown in Fig. 22.

[0138] The switch elements of the power supply circuits 6, 60, 60a to 60c, 600, and 6000 are not limited to transistors, but may be any elements capable of switching between a conductive state and a cut-off state between the power supply and the actuator.

[0139] Furthermore, the actuators 30 to which power is supplied by the above-mentioned power supply circuits 6, 60, 60a to 60c, 600, 6000 are not limited to actuators that open and close control valves 41, 42, or 43, but may also be actuators for various valves 18, 19, 47, 172 whose opening and closing is controlled by the controller 10. [Explanation of symbols]

[0140] 1 Temperature control device for secondary batteries 10 Controllers 12 Supply route 18 First three-way valve (shutoff valve) 2 cells 20 Main Surface 21 Cell 1 22 Cell 2 23 Cell 3 210 First thermistor (temperature sensor) 220 Second thermistor (temperature sensor) 230 Third thermistor (temperature sensor) 3 Refrigerant passage 30 Actuator (drive unit) 31 First refrigerant passage 32 Second refrigerant passage 33 Third refrigerant passage 41 First control valve 42 Second control valve 43 Third control valve 44 First shut-off valve 45 Second shut-off valve 46 Third shut-off valve 47 First release valve 611 1st power supply 61 1st circuit 62 2nd circuit 62a 2nd circuit 62b 2nd circuit 620 2nd circuit 621 2nd power supply 621a 2nd power supply 621b 2nd power supply 622 Second switch element 626 2nd power supply 627 2nd power supply 63 Thermoelectric element

Claims

1. a first cell having a first major surface; a second cell having a second major surface opposite the first major surface; a first refrigerant passage located between the first main surface and the second main surface, through which a refrigerant flows to cool the first cells through the first main surface and the second cells through the second main surface; an on-off valve that opens the first refrigerant passage so that the refrigerant is discharged from the first refrigerant passage when the temperature of the first cell exceeds a predetermined temperature, Temperature control device for secondary batteries.

2. 2. The temperature control device for a secondary battery according to claim 1, a first control valve that opens and closes the first refrigerant passage; a controller that outputs a control signal to the first control valve; a temperature sensor that outputs a measurement signal corresponding to the temperature of the first cell to the controller; When the temperature of the first cell is equal to or lower than a predetermined temperature, the controller opens the first control valve to allow the refrigerant to flow through the first refrigerant passage, and when the temperature of the first cell exceeds the predetermined temperature, the controller closes the first control valve to stop the flow of the refrigerant through the first refrigerant passage and vaporize the refrigerant in the first refrigerant passage. Temperature control device for secondary batteries.

3. 3. The temperature control device for a secondary battery according to claim 2, the on-off valve opens the first refrigerant passage when the internal pressure of the first refrigerant passage exceeds a predetermined pressure due to evaporation of the refrigerant. Temperature control device for secondary batteries.

4. 4. The temperature control device for a secondary battery according to claim 3, a supply passage connected to the first refrigerant passage and configured to supply the cooled refrigerant to the first refrigerant passage; a shutoff valve that shuts off the supply path in response to a control signal from the controller; an open valve located in the supply path between the shutoff valve and the first refrigerant passage, the open valve opening the supply path and the first refrigerant passage to the atmosphere, the controller closes the shutoff valve and opens the open valve when the temperature of the first cell exceeds a second predetermined temperature after closing the first control valve; Temperature control device for secondary batteries.

5. The temperature control device for a secondary battery according to any one of claims 2 to 4, a third cell located on the opposite side of the second cell from the first cell and having a fourth major surface facing the third major surface of the second cell; a second refrigerant passage located between the third main surface and the fourth main surface, through which the refrigerant flows to cool the second cells through the third main surface and the third cells through the fourth main surface; a second control valve that opens and closes the second refrigerant passage, When the temperature of the first cell exceeds a predetermined temperature, the controller closes the first control valve to stop the flow of the refrigerant in the first refrigerant passage and keeps the second control valve open. Temperature control device for secondary batteries.

6. The temperature control device for a secondary battery according to any one of claims 2 to 4, a fourth cell located on the opposite side of the first cell from the second cell and having a sixth major surface facing the fifth major surface of the first cell; a third refrigerant passage located between the fifth main surface and the sixth main surface, through which the refrigerant flows to cool the first cells through the fifth main surface and the fourth cells through the sixth main surface; a third control valve that opens and closes the third refrigerant passage, the controller closes the first control valve and the third control valve when the temperature of the first cell exceeds a predetermined temperature, thereby stopping the flow of the refrigerant in the first refrigerant passage and the third refrigerant passage. Temperature control device for secondary batteries.

7. 3. The temperature control device for a secondary battery according to claim 2, a first power source; a first circuit that supplies power from the first power source to a drive unit of the first control valve to close the first control valve; A second power source; a second circuit connected in parallel to the first circuit, the second circuit supplying power from the second power source to a drive unit of the first control valve to close the first control valve; Further provided with Temperature control device for secondary batteries.

8. 8. The temperature control device for a secondary battery according to claim 7, the second power source includes a thermoelectric element attached to the first cell and the second cell, and generates electricity when the temperature of the first cell or the second cell increases. Temperature control device for secondary batteries.

9. 8. The temperature control device for a secondary battery according to claim 7, The secondary battery is mounted on a vehicle, the first power source is a 12V battery; the second power source is a capacitor mounted on the vehicle; Temperature control device for secondary batteries.

10. 8. The temperature control device for a secondary battery according to claim 7, The second power source is an emergency power source. Temperature control device for secondary batteries.

11. The temperature control device for a secondary battery according to any one of claims 8 to 10, the second circuit has a switch element that switches between a conductive state in which power from the second power source is supplied to a drive portion of the first control valve and a cut-off state in which the supply of power is cut off, the switch element is attached to the first cell and the second cell, and is switched to a conductive state by an electromotive force of a thermoelectric element that generates electricity when the temperature of the first cell or the second cell increases; Temperature control device for secondary batteries.

12. a refrigerant is caused to flow through a refrigerant passage located between a first main surface of a first cell and a second main surface of a second cell, thereby cooling the first cell through the first main surface and cooling the second cell through the second main surface; When the temperature of the first cell exceeds a predetermined temperature, the refrigerant is discharged from the refrigerant passage through the open / close valve. A method for controlling the temperature of a secondary battery.

13. The method for controlling the temperature of a secondary battery according to claim 12, when the temperature of the first cell exceeds a predetermined temperature and before the on-off valve opens, a control valve closes the refrigerant passage in response to a control signal from a controller, thereby stopping the flow of the refrigerant in the refrigerant passage and vaporizing the refrigerant in the refrigerant passage; A method for controlling the temperature of a secondary battery.

14. The method for controlling the temperature of a secondary battery according to claim 13, When the internal pressure of the refrigerant passage exceeds a predetermined pressure due to evaporation of the refrigerant, the on-off valve opens to open the refrigerant passage. A method for controlling the temperature of a secondary battery.

Images