Battery cell temperature management device

Abstract

The battery cell temperature management device (1) of the present application warms up a battery cell quickly. It is provided with: a battery cell (10) that can perform charge and discharge; a heater (40) that operates by power supply from the battery cell and heats a heat exchange medium (W) that exchanges heat with the battery cell; a variable mechanism (50) that varies the heat transfer capacity between the battery cell and the heat exchange medium; and a control device (60) that controls the heating of the heat exchange medium by the heater and the variation of the heat transfer capacity by the variable mechanism. When the heat exchange medium is heated by the heater, in the case where the temperature (Tw) of the heat exchange medium does not reach a first temperature (T1) that is equal to the temperature (Tm) of the battery cell, the control device makes the heat transfer capacity smaller than in the case where the temperature of the heat exchange medium reaches the first temperature.

Description

Technical Field

[0001] This invention relates to a battery cell temperature management device. Background Technology

[0002] In electric vehicles and hybrid vehicles equipped with battery cells (such as secondary batteries) for electric motor drive, if the temperature of the battery cells drops in cold weather, the electromotive force of the battery cells may decrease, leading to a reduction in vehicle performance. To prevent this, structures are known that use a heat exchange medium heated by an electric heater to heat the battery cells.

[0003] For example, the secondary battery heating device for a hybrid vehicle disclosed in Patent Document 1 includes an internal combustion engine, a lithium-ion battery (battery cell), and a heating device. The heating device includes: a latent heat storage material; a cooling water storage tank that supplies cooling water (heat exchange medium) to the internal combustion engine and transfers heat to the latent heat storage material; a cooling water passage that allows cooling water to circulate between the cooling water storage tank and the internal combustion engine; and an electric heater disposed in the cooling water storage tank and heating the cooling water in the cooling water storage tank.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2017-222239

[0007] However, if the temperature of the heat exchange medium heated by the heater does not reach the temperature of the battery cell, heat may sometimes move from the battery cell to the heat exchange medium, thus delaying the temperature rise of the battery cell. If the temperature rise of the battery cell is delayed, its capabilities cannot be fully utilized, especially in cold conditions. Summary of the Invention

[0008] The present invention was made in view of the above-mentioned problems, and its purpose is to enable the battery cell to heat up rapidly.

[0009] The battery cell temperature management device according to the present invention includes: a battery cell capable of charging and discharging; a heater that operates by power supply from the battery cell and heats a heat exchange medium that exchanges heat with the battery cell; a variable mechanism that varies the heat transfer capacity between the battery cell and the heat exchange medium; and a control device that controls the heating of the heat exchange medium by the heater and the variation in heat transfer capacity caused by the variable mechanism. When the heat exchange medium is heated by the heater, if the temperature of the heat exchange medium does not reach a first temperature equal to the temperature of the battery cell, the control device reduces the heat transfer capacity compared to if the temperature of the heat exchange medium reaches the first temperature.

[0010] According to this structure, when the heat exchange medium is heated by the heater, if the temperature of the heat exchange medium has not reached a first temperature equal to the temperature of the battery cell, the heat transfer capacity between the battery cell and the heat exchange medium is reduced by controlling the variable mechanism using a control device. Therefore, heat movement from the battery cell to the heat exchange medium is suppressed, thereby suppressing the temperature rise delay of the battery cell.

[0011] Furthermore, after the temperature of the heat exchange medium reaches a first temperature equal to the temperature of the battery cell, the heat transfer capacity between the battery cell and the heat exchange medium is increased by controlling the variable mechanism using a control device. At this point, since the temperature of the heat exchange medium is already higher than the temperature of the battery cell (the first temperature), even if the heat transfer capacity between the battery cell and the heat exchange medium is increased, there is almost no heat movement from the battery cell to the heat exchange medium; instead, heat movement from the heat exchange medium to the battery cell is promoted.

[0012] In this way, before and after the temperature of the heat exchange medium reaches the first temperature equal to that of the battery cell, the heat transfer capacity between the battery cell and the heat exchange medium changes, thereby enabling the battery cell to heat up rapidly.

[0013] In one embodiment, the variable mechanism can switch the heat exchange mode between the battery cell and the heat exchange medium between an adiabatic mode that inhibits heat exchange and a heat transfer mode that promotes heat exchange. When the heat exchange medium is heated by the heater, if the temperature of the heat exchange medium does not reach the first temperature, the control device sets the heat exchange mode to the adiabatic mode. On the other hand, if the temperature of the heat exchange medium reaches the first temperature, the control device sets the heat exchange mode to the heat transfer mode.

[0014] According to this structure, the heat exchange mode is switched from adiabatic mode to heat transfer mode before and after the temperature of the heat exchange medium reaches the first temperature, thereby making it easier to accelerate the heating of the battery cell.

[0015] In one embodiment, the control device controls the heating of the heat exchange medium by the heater and the change in heat transfer capacity generated by the variable mechanism based on whether the heat exchange medium has reached the first temperature and whether the battery cell has reached the second temperature at which the internal resistance of the battery cell has decreased to saturation.

[0016] When the internal resistance of a battery cell is high, its capacity cannot be fully utilized; for example, it may be impossible to drive a motor using the battery cell. Here, as the battery cell charges and discharges, it generates internal heat and its temperature rises. The internal resistance of the battery cell decreases as its temperature rises, and saturates when the battery cell reaches a second temperature.

[0017] Therefore, in order to fully utilize the capabilities of the battery cell, it is preferable to use the internal heat generated by the battery cell to rapidly raise the temperature of the battery cell to the second temperature. Furthermore, in order to effectively heat the battery cell, it is preferable to rapidly raise the temperature of the heat exchange medium to the first temperature.

[0018] According to this structure, by taking into account whether the heat exchange medium has reached a first temperature and whether the battery cell has reached a second temperature, the temperature of the battery cell and the heat exchange medium can be effectively increased.

[0019] In one embodiment, when the heat exchange medium is heated by the heater, if the battery cell reaches the second temperature at the moment the heat exchange medium reaches the first temperature, the control device stops the power supply from the battery cell to the heater and switches the heat exchange mode from the adiabatic mode to the heat transfer mode.

[0020] According to this structure, since the heat exchange medium has reached a first temperature, by switching the heat exchange mode from the adiabatic mode to the heat transfer mode, the temperature of the battery cell can be effectively increased by promoting the thermal movement from the heat exchange medium to the battery cell.

[0021] On the other hand, since the battery cell has already reached the second temperature, there is no need to further supply power (discharge) from the battery cell to the heater in order to reduce the internal resistance of the battery cell. Therefore, stopping the power supply from the battery cell to the heater can eliminate unnecessary power consumption of the battery cell.

[0022] In one embodiment, when the heat exchange medium is heated by the heater, if the battery cell has not reached the second temperature when the heat exchange medium reaches the first temperature, the control device does not stop the power supply from the battery cell to the heater and reduces the power supply compared to the power supply before the heat exchange medium reaches the first temperature, and switches the heat exchange mode from the adiabatic mode to the heat transfer mode.

[0023] According to this structure, similarly to the above, since the heat exchange medium has reached the first temperature, by switching the heat exchange mode from the adiabatic mode to the heat transfer mode, the temperature of the battery cell can be effectively increased by promoting the thermal movement from the heat exchange medium to the battery cell.

[0024] On the other hand, since the battery cell has not reached the second temperature, it is necessary to continuously maintain the power supply (discharge) from the battery cell to the heater in order to reduce the internal resistance of the battery cell. However, as described above, the heat transfer mode promotes the thermal movement from the heat exchange medium to the battery cell, so the power supply from the battery cell to the heater can be reduced compared to before the temperature of the heat exchange medium reaches the first temperature. Thus, it is possible to raise the temperature of the battery cell to the second temperature while minimizing the power consumption of the battery cell.

[0025] In one embodiment, when the heat exchange medium is heated by the heater, if the heat exchange medium does not reach the first temperature when the battery cell reaches the second temperature, the control device maintains the heat exchange mode in the adiabatic mode while starting to supply power to the heater from an external power source.

[0026] According to this structure, since the battery cell has already reached the second temperature, there is no need to further supply power (discharge) from the battery cell to the heater in order to reduce the internal resistance of the battery cell.

[0027] On the other hand, since the temperature of the heat exchange medium has not reached the first temperature, it is necessary to maintain the heat exchange mode in an adiabatic mode while continuing to supply power to the heater from the battery cell or other power sources. Therefore, power supply to the heater from an external power source is initiated. This allows for the suppression or stopping of power supply from the battery cell to the heater. Thus, by using an external power source, it is possible to suppress power consumption by the battery cell while simultaneously raising the temperature of the heat exchange medium to the first temperature.

[0028] In one embodiment, the battery cell is composed of a plurality of battery cells arranged in an array, and the variable mechanism includes: a heat transfer element that exchanges heat with the heat exchange medium and is disposed between adjacent battery cells; and an area changing mechanism that changes the heat transfer capacity between the battery cells and the heat exchange medium by changing the contact area between the heat transfer element and the battery cells.

[0029] Based on this structure, the heat transfer capacity between the battery cell and the heat exchange medium can be easily varied.

[0030] In one embodiment, the device includes: a plurality of battery cells; a plurality of variable mechanisms arranged to correspond to each of the battery cells; and a flow path through which the heat exchange medium circulates through each of the battery cells, the heat exchange medium being heated by a heater disposed in the flow path and shared among the plurality of battery cells, and the control device causing the heat transfer capacity between the battery cells farther from the shared heater and the heat exchange medium to be greater than the heat transfer capacity between the battery cells closer to the shared heater and the heat exchange medium.

[0031] The heat exchange medium in contact with battery cells farther from the shared heater tends to have a lower temperature compared to the heat exchange medium in contact with battery cells closer to the shared heater. According to this structure, the battery cells farther from the shared heater can more easily exchange heat with the heat exchange medium compared to those closer to the shared heater. Therefore, it is possible for multiple battery cells to experience an equal temperature rise regardless of their distance from the shared heater.

[0032] In one embodiment, the device includes: a plurality of battery cells; a plurality of variable mechanisms arranged to correspond to each of the battery cells; and a flow path through which the heat exchange medium circulates through each of the battery cells, the heat exchange medium being heated by a heater disposed in the flow path and shared among the plurality of battery cells, and the control device alternately supplying power from at least a portion of the battery cells to the shared heater.

[0033] This structure can promote internal heating of the battery cell and efficiently reduce the internal resistance of the battery cell.

[0034] In one embodiment, the system includes: a plurality of variable mechanisms arranged to correspond to each of the battery cells; a plurality of battery cells; and a flow path through which the heat exchange medium circulates via each of the battery cells. The heat exchange medium is heated by a plurality of heaters corresponding to each of the battery cells. The control device controls the circulation of the heat exchange medium in the flow path. When the heat exchange medium is heated by the heaters, the control device prevents the heat exchange medium from circulating in the flow path if the heat exchange medium does not reach the first temperature.

[0035] This structure enables the heat exchange medium to be rapidly heated to a first temperature.

[0036] According to the present invention, the battery cell can be heated rapidly. Attached Figure Description

[0037] Figure 1 This is a schematic structural diagram of the battery cell temperature management device according to the first embodiment of the present invention.

[0038] Figure 2 This is an exploded 3D view of a battery cell.

[0039] Figure 3 This is a cross-sectional view of the battery cell in adiabatic mode.

[0040] Figure 4 This is a cross-sectional view of a battery cell in heat transfer mode.

[0041] Figure 5 It is a graph showing the relationship between temperature and internal resistance in a battery cell.

[0042] Figure 6 It is a graph showing the relationship between temperature and degradation characteristics in a battery cell.

[0043] Figure 7 It is a graph representing the first heating mode of the battery cell and the heat exchange medium.

[0044] Figure 8 This is a graph representing the second heating mode of the battery cell and the heat exchange medium.

[0045] Figure 9 This is a graph representing the third heating mode of the battery cell and the heat exchange medium.

[0046] Figure 10 This is a graph illustrating an example of how the battery cell and heat exchange medium heat up.

[0047] Figure 11This is a flowchart illustrating an example of the control method of the battery cell temperature management device according to the first embodiment (starting with heating the battery cell via a heat exchange medium).

[0048] Figure 12 This is a flowchart illustrating an example of the control method of the battery cell temperature management device according to the first embodiment (temperature uniformity among battery cells).

[0049] Figure 13 The variations of the first embodiment involve the following: Figure 1 A fairly accurate diagram.

[0050] Figure 14 This is a schematic structural diagram of the battery cell temperature management device according to the second embodiment.

[0051] Figure 15 This is a flowchart illustrating an example of the control method of the battery cell temperature management device according to the second embodiment.

[0052] Symbol Explanation

[0053] 1 Battery cell temperature management device

[0054] 10 battery cells

[0055] 11 battery cells

[0056] 20 Battery Temperature Sensor

[0057] 30 flow path

[0058] 35 Medium Temperature Sensor

[0059] 40 heaters

[0060] 50 variable mechanism

[0061] 51 heat transfer components

[0062] 52 Electromagnetic Solenoid (Area Changing Mechanism)

[0063] 60 control devices

[0064] 70 external power supply

[0065] E1 power supply

[0066] E2 power supply

[0067] C External charging

[0068] W heat exchange medium

[0069] Tw temperature

[0070] Tm temperature

[0071] T1 First Temperature

[0072] T2 Second Temperature

[0073] R Internal resistance

[0074] F constraint force

[0075] time t Detailed Implementation

[0076] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following description of preferred embodiments is merely illustrative in nature and is not intended to limit the invention, its applicability, or its uses.

[0077] <First Implementation>

[0078] (Basic structure of battery cell temperature management device)

[0079] Figure 1 This is a schematic structural diagram of the battery cell temperature management device 1 according to the first embodiment of the present invention. The battery cell temperature management device 1 is mounted on a vehicle (not shown) such as an electric vehicle or a hybrid vehicle. In this embodiment, the vehicle is an electric vehicle and is equipped with an electric motor (not shown). The battery cell temperature management device 1 manages the temperature of the battery cell (battery module) 10, which will be described later.

[0080] The battery cell temperature management device 1 includes: multiple battery cells 10, multiple battery temperature sensors 20, flow path 30, pump 31, valve 32, valve 33, heat exchanger 34, medium temperature sensor 35, heater 40, multiple variable mechanisms 50, and control device 60.

[0081] Each battery cell 10 is capable of charging and discharging, and is mainly used to drive the electric motor. The battery cell 10 is, for example, a lithium-ion battery. The battery cell 10 has four cells in total: a first battery cell 10A, a second battery cell 10B, a third battery cell 10C, and a fourth battery cell 10D.

[0082] Each battery temperature sensor 20 is configured to correspond to each battery cell 10, detecting the temperature Tm of each battery cell 10. There are four battery temperature sensors 20: a first battery temperature sensor 20A, a second battery temperature sensor 20B, a third battery temperature sensor 20C, and a fourth battery temperature sensor 20D. The first battery temperature sensor 20A is located near the first battery cell 10A and detects its temperature TmA. The second battery temperature sensor 20B is located near the second battery cell 10B and detects its temperature TmB. The third battery temperature sensor 20C is located near the third battery cell 10C and detects its temperature TmC. The fourth battery temperature sensor 20D is located near the fourth battery cell 10D and detects its temperature TmD.

[0083] The heat exchange medium W circulates in the flow path 30. The heat exchange medium W flowing in the flow path 30 passes alongside each battery cell 10. By allowing the heat exchange medium W to pass alongside each battery cell 10, heat exchange occurs between the heat exchange medium W and each battery cell 10. The heat exchange medium W is, for example, electric motor cooling water.

[0084] Here, each battery cell 10 flows along the flow direction of the flow path 30 (refer to...). Figure 1 (Arrow) Configuration. Each battery cell 10 is arranged from the upstream side to the downstream side of the flow path 30 in the order of first battery cell 10A, second battery cell 10B, third battery cell 10C, and fourth battery cell 10D.

[0085] A pump 31, valve 32, valve 33, heat exchanger 34, medium temperature sensor 35, and heater 40 are arranged in the middle of the flow path 30. The pump 31 is arranged upstream of the battery cell 10 in the flow path 30 and supplies the heat exchange medium W to the battery cell 10.

[0086] Valves 32 and 33 switch the flow of heat exchange medium W in flow path 30. Specifically, valves 32 and 33 switch the flow of heat exchange medium W in flow path 30 between bypass flow path 30A that bypasses heat exchanger 34 and heat exchange flow path 30B that passes through heat exchanger 34.

[0087] The heat exchanger 34 is, for example, a radiator, which uses the airflow from the vehicle to cool the heat exchange medium W. A fan may also be installed next to the heat exchanger 34. In this embodiment, the heat exchange medium W bypasses the heat exchanger 34 and flows through the bypass path 30A. That is, the heat exchange medium W is not cooled by the heat exchanger 34.

[0088] The medium temperature sensor 35 detects the temperature Tw of the heat exchange medium W in the flow path 30.

[0089] Heater 40 is an electric heater, disposed upstream of battery cell 10 in flow path 30. Heater 40 operates by power supply (discharge) E1 from battery cell 10. Heater 40 heats heat exchange medium W. Heater 40 is shared among multiple battery cells 10. Heat exchange medium W is used as a heating medium to raise the temperature of each battery cell 10.

[0090] Each variable mechanism 50 is configured to correspond to each battery cell 10, thereby varying the heat transfer capacity between each battery cell 10 and the heat exchange medium W. The variable mechanisms 50 include four mechanisms: a first variable mechanism 50A, a second variable mechanism 50B, a third variable mechanism 50C, and a fourth variable mechanism 50D. The first variable mechanism 50A varies the heat transfer capacity between the first battery cell 10A and the heat exchange medium W. The second variable mechanism 50B varies the heat transfer capacity between the second battery cell 10B and the heat exchange medium W. The third variable mechanism 50C varies the heat transfer capacity between the third battery cell 10C and the heat exchange medium W. The fourth variable mechanism 50D varies the heat transfer capacity between the fourth battery cell 10D and the heat exchange medium W.

[0091] Here, "heat transfer capability" refers to the ease with which heat exchange occurs between the battery cell 10 and the heat exchange medium W. A higher heat transfer capability makes heat exchange easier, while a lower heat transfer capability makes heat exchange more difficult. Heat transfer capability can be, for example, the heat transfer coefficient or thermal conductivity. Details regarding the variable mechanism 50 will be described later.

[0092] The control device 60 controls the heating of the heat exchange medium W by the heater 40. In addition, the control device 60 controls the change in the heat transfer capacity between each battery cell 10 and the heat exchange medium W caused by each variable mechanism 50 for each battery cell 10.

[0093] Furthermore, each variable mechanism 50 can switch the heat exchange mode between each battery cell 10 and the heat exchange medium W between an adiabatic mode that inhibits heat exchange and a heat transfer mode that promotes heat exchange. Compared to the heat transfer mode, the heat transfer capacity between each battery cell 10 and the heat exchange medium W is relatively small in the adiabatic mode. On the other hand, compared to the adiabatic mode, the heat transfer capacity between each battery cell 10 and the heat exchange medium W is relatively large in the heat transfer mode. The specific control method of the control device 60 will be described later. The control device 60 is, for example, composed of a microcomputer and a program.

[0094] The control device 60 controls the circulation of the heat exchange medium W in the flow path 30. Specifically, the control device 60 controls the flow rate / pressure of the heat exchange medium W flowing in the flow path 30 by controlling the discharge pressure / discharge rate of the pump 31 and the opening and closing of valves 32 and 33.

[0095] The heater 40 also operates by supplying power to E2 from an external power source 70 (such as a charging station). Furthermore, the external power source 70 is primarily used for external charging (C) of the battery cell 10. In order to externally charge (C) the battery cell 10 via the external power source 70, the temperature Tm of the battery cell 10 needs to be raised to a certain level beforehand.

[0096] (Battery unit)

[0097] Figure 2 This is an exploded perspective view of battery cell 10. Figure 3 , 4 This is a cross-sectional view of battery cell 10. (For example...) Figures 2-4 As shown, the battery unit 10 is composed of a plurality of battery cells 11 arranged in an array. Each battery cell 11 is housed in a housing 12. Each battery cell 1 is a flat, roughly rectangular parallelepiped shape, arranged with its larger faces overlapping each other. A positive terminal 13 and a negative terminal 14 are provided on one side of each battery cell 11. Figure 3 , 4 As shown, the battery cells 11 are electrically connected to each other via the busbar spring 15.

[0098] like Figures 2-4 As shown, the variable mechanism 50 includes a heat transfer element 51 and an electromagnetic solenoid 52 serving as an area-changing mechanism. The heat transfer element 51 is disposed between adjacent battery cells 11. The heat transfer element 51 is formed in a corrugated plate shape. The heat transfer element 51 is formed, for example, from copper, aluminum, or the like.

[0099] When the heat transfer element 51 is subjected to an external force in the normal direction of its surface, i.e., an external force in the direction in which the battery cells 11 are arranged, its shape changes from a corrugated plate shape to a flat plate shape. In addition, the heat transfer element 51 has a heat transfer surface 51a for exchanging heat with the heat exchange medium W passing next to the battery cells 10.

[0100] The electromagnetic solenoid 52 is a type of pressing mechanism that applies external force to multiple battery cells 11 in the direction in which the battery cells 11 are arranged. The electromagnetic solenoid 52 is switched between a pulling direction and an extending direction by a control device 60. When the electromagnetic solenoid 52 is in the pulling direction, the multiple battery cells 11 are not constrained. When the electromagnetic solenoid 52 is in the extending direction, the multiple battery cells 11 are constrained.

[0101] Hereinafter, the force by which the electromagnetic solenoid 52 of the variable mechanism 50 constrains the multiple battery cells 11 will be referred to as the constraint force F. The constraint force generated by the first variable mechanism 50A will be designated as FA, the constraint force generated by the second variable mechanism 50B as FB, the constraint force generated by the third variable mechanism 50C as FC, and the constraint force generated by the fourth variable mechanism 50D as FD.

[0102] The electromagnetic solenoid 52 changes the heat transfer capacity between the battery cell 11 and the heat exchange medium W by varying the contact area between the heat transfer element 51 and the battery cell 11, as detailed later. When the electromagnetic solenoid 52 is in the pulling direction, the heat exchange mode is adiabatic. When the electromagnetic solenoid 52 is in the extending direction, the heat exchange mode is heat transfer.

[0103] Figure 3 This indicates that the variable mechanism 50 is in adiabatic mode (the electromagnetic solenoid 52 is in the pulling direction). Figure 4 This indicates the case where the variable mechanism 50 is in heat transfer mode (the electromagnetic solenoid 52 is in the extension direction). For example... Figure 3 As shown, since the heat transfer element 51 is corrugated, an air layer is formed between the battery cells 11 when the electromagnetic solenoid 52 is in the pulling direction. Furthermore, when the electromagnetic solenoid 52 is in the pulling direction, the heat transfer element 51 and the battery cells 11 are not in close contact.

[0104] That is, when the electromagnetic solenoid 52 is in the pulling direction, the contact area between the heat transfer element 51 and the battery cell 11 becomes smaller, thus the heat transfer element 51 and the battery cell 11 become adiabatic. As a result, heat exchange between the battery cell 10 (each battery cell 11) and the heat exchange medium W is suppressed (adiabatic mode).

[0105] like Figure 4 As shown, when the electromagnetic solenoid 52 is in the extending direction, an external force is applied to the multiple battery cells 11, causing the heat transfer element 51 to become a flat plate shape, thus preventing the formation of an air layer between the battery cells 11. Furthermore, when the electromagnetic solenoid 52 is in the extending direction, the heat transfer element 51 and the battery cells 11 are in close contact with each other.

[0106] That is, when the electromagnetic solenoid 52 is in the extending direction, the contact area between the heat transfer element 51 and the battery cell 11 increases, thereby enabling the heat transfer element 51 and the battery cell 11 to enter a heat transfer state. This promotes heat exchange (heat transfer mode) between the battery cell 10 (each battery cell 11) and the heat exchange medium W.

[0107] In addition, the variable mechanism 50 can also be in an adiabatic mode (with the electromagnetic solenoid 52 in the pulling direction, Figure 3 ) and heat transfer mode (electromagnetic solenoid 52 is in the extension direction, Figure 4 The intermediate mode is used as the heat exchange mode. Therefore, the heat transfer capability between the battery cell 11 and the heat exchange medium W can be fine-tuned.

[0108] (Temperature of the heat exchange medium)

[0109] In electric vehicles, if the temperature of the battery cell 10 decreases in cold weather, the electromotive force of the battery cell 10 may decrease, leading to a reduction in the vehicle's driving performance. To prevent this, it is desirable to rapidly heat (preheat) the battery cell 10 using the heat exchange medium W heated by the heater 40.

[0110] However, if the temperature Tw of the heat exchange medium W heated by the heater 40 does not reach the first temperature T1 equal to the temperature of the battery cell 10, thermal migration may occur from the battery cell 10 to the heat exchange medium W, resulting in a delay in the temperature rise of the battery cell 10. If the temperature rise of the battery cell 10 is delayed, its capabilities cannot be fully utilized, especially in cold conditions.

[0111] Therefore, it is necessary to rapidly heat up the battery cell 10. To achieve this, the temperature Tw of the heat exchange medium W needs to rapidly reach the first temperature T1. When the temperature Tw of the heat exchange medium W reaches the first temperature T1, the battery cell 10 can be heated through the heat exchange medium W.

[0112] In addition, the first temperature T1 may include a temperature that is exactly the same as the temperature Tm of the battery cell 10 or a temperature that deviates from the temperature Tm of the battery cell 10 by about ±3°C (T1≈Tm).

[0113] (Battery cell temperature)

[0114] Figure 5 This is a graph showing the relationship between the temperature Tm (°C) and the internal resistance R in battery cell 10. When the internal resistance R of battery cell 10 is high, the capacity of battery cell 10 cannot be fully utilized; for example, sometimes battery cell 10 cannot be used to drive a motor.

[0115] Here, as power is supplied (discharged) E1 from battery cell 10 to heater 40, battery cell 10 generates internal heat and its temperature rises. For example... Figure 5 As shown, the internal resistance R of the battery cell 10 decreases as the temperature Tm of the battery cell 10 increases, and saturates when the temperature Tm of the battery cell 10 reaches a second temperature T2. That is, the second temperature T2 is the temperature at which the internal resistance R of the battery cell 10 decreases to saturation. Furthermore, even if the temperature Tm of the battery cell 10 does not reach the second temperature T2, it is possible to supply power E1 from the battery cell 10 to the heater 40.

[0116] (Temperature management of battery cells and heat exchange medium)

[0117] The management of the temperature Tm of the battery cell 10 and the temperature Tw of the heat exchange medium W is explained. The control device 60 controls the heating of the heat exchange medium W by the heater 40 and the change in the heat transfer capacity between the battery cell 10 and the heat exchange medium W caused by the variable mechanism 50 based on whether the temperature Tw of the heat exchange medium W reaches the first temperature T1 and whether the temperature Tm of the battery cell 10 reaches the second temperature T2.

[0118] When the heater 40 heats the heat exchange medium W, if the temperature Tw of the heat exchange medium W has not reached the first temperature T1, the control device 60 makes the heat transfer capacity between the battery cell 10 and the heat exchange medium W smaller compared to the case where the temperature Tw of the heat exchange medium W has reached the first temperature T1.

[0119] In detail, when the heat exchange medium W is heated by the heater 40, if the temperature Tw of the heat exchange medium W has not reached the first temperature T1, the control device 60 sets the heat exchange mode between the battery cell 10 and the heat exchange medium W to an adiabatic mode (see reference). Figure 3 On the other hand, when the heat exchange medium W is heated using the heater 40, if the temperature Tw of the heat exchange medium W reaches the first temperature T1, the control device 60 sets the heat exchange mode between the battery cell 10 and the heat exchange medium W to heat transfer mode (see reference). Figure 4 ).

[0120] (Normal degradation and high-rate degradation)

[0121] Figure 6 This is a graph showing the relationship between the temperature Tm (°C) in battery cell 10 and its degradation characteristics. Regardless of the vehicle's operating state or the charge / discharge state of battery cell 10, the higher the temperature Tm of battery cell 10, the more advanced the normal degradation A1 becomes. On the other hand, when battery cell 10 is charged and discharged at a high rate (rapid), in addition to normal degradation A1, high-rate degradation A2 also occurs. The lower the temperature Tm of battery cell 10, the more advanced the high-rate degradation A2 becomes. That is, the combined degradation A3, which combines normal degradation A1 and high-rate degradation A2, has a minimum value.

[0122] Therefore, when charging and discharging the battery cell 10 at a low (normal) rate, it is sufficient to set the temperature Tm of the battery cell 10 to a low temperature. However, when charging and discharging the battery cell 10 at a high rate, the temperature Tm of the battery cell 10 must be fine-tuned to the intermediate target management temperature B range. That is, when charging and discharging the battery cell 10 at a high rate, temperature management of the battery cell 10 becomes difficult.

[0123] (Heating mode of battery cells and heat exchange medium)

[0124] Figure 7 This is a graph representing the first heating mode P1 of battery cell 10 and heat exchange medium W. Figure 8 This is a graph representing the second heating mode P2 of battery cell 10 and heat exchange medium W. Figure 9 This is a graph representing the third heating mode P3 of battery cell 10 and heat exchange medium W. Figures 7-9 In the diagram, the horizontal axis represents time, and the vertical axis represents temperature (°C).

[0125] like Figure 7 As shown, in the first heating mode P1, when the heat exchange medium W is heated by the heater 40, at time t when the temperature Tw of the heat exchange medium W reaches the first temperature T1, the temperature Tm of the battery cell 10 has already reached the second temperature T2. In this case, the control device 60 stops the power supply E1 from the battery cell 10 to the heater 40 and switches the heat exchange mode from the adiabatic mode (see reference). Figure 3 Switch to heat transfer mode (refer to) Figure 4 ).

[0126] like Figure 8 As shown, in the second heating mode P2, when the heat exchange medium W is heated by the heater 40, at time t when the temperature Tw of the heat exchange medium W reaches the first temperature T1, the temperature Tm of the battery cell 10 has not reached the second temperature T2. In this case, the control device 60 does not stop the power supply E1 from the battery cell 10 to the heater 40 and reduces the power supply E1 compared to the power supply E1 before the temperature Tw of the heat exchange medium W reaches the first temperature T1 (before time t). Specifically, the power supply E1 from the battery cell 10 to the heater 40 is reduced to a level that maintains the temperature of the heat exchange medium W (but does not heat it). Moreover, the control device 60 changes the heat exchange mode from the adiabatic mode (see reference...) Figure 3 Switch to heat transfer mode (refer to) Figure 4 ).

[0127] like Figure 9 As shown, in the third heating mode P3, when the heat exchange medium W is heated by the heater 40, at time t when the temperature Tm of the battery cell 10 reaches the second temperature T2, the temperature Tw of the heat exchange medium W has not reached the first temperature T1. In this case, the control device 60 maintains the heat exchange mode in adiabatic mode (see reference). Figure 3 The control device 60 maintains the power supply E1 from the battery cell 10 to the heater 40. Furthermore, the control device 60 begins to supply power E2 from the external power source 70 to the heater 40.

[0128] Figure 10This is a graph illustrating an example of the heating method of battery cell 10 and heat exchange medium W. In Figure 10 In the diagram, the horizontal axis represents time, and the vertical axis represents the internal temperature Tm (°C) of battery cell 10. At time t0, the temperature of battery cell Tm is Tm0. At time t0, the power supply (discharge) E1 from battery cell 10 to heater 40 begins. Furthermore, at time t0, the heat exchange mode is adiabatic mode (see reference). Figure 3 ).

[0129] At time t1, the temperature Tm of battery cell 10 rises to Tm1. If the temperature Tm of battery cell 10 is Tm1, external charging C can be performed on battery cell 10 via external power supply 70. At time t1, the power supply E1 from battery cell 10 to heater 40 stops. Instead, at time t1, the power supply E2 from external power supply 70 begins to the heater 40. Simultaneously, at time t1, high-rate external charging C of battery cell 10 via external power supply 70 begins.

[0130] Here, at time t1, the temperature Tm (Tm1) of the battery cell 10 is still low. Therefore, if the battery cell 10 is externally charged (C) at a high rate by the external power supply 70, high-rate degradation of the battery cell 10 may occur. However, the high-rate degradation is eliminated by the high-rate discharge performed by the battery cell 10, which will be described later.

[0131] At time t2, the temperature Tm of battery cell 10 rises to Tm2. At time t2, the high-rate external charging C of battery cell 10 by external power source 70 is stopped. Simultaneously, at time t2, power supply (discharge) E1 from battery cell 10 to heater 40 begins at the same rate as the external charging (C) of battery cell 10 by external power source 70 described above. Thus, the high-rate degradation of battery cell 10 is eliminated.

[0132] At time t3, the temperature Tm of battery cell 10 rises to Tm3. Additionally, at time t3, the temperature Tw of heat exchange medium W reaches the same Tm3 as the temperature Tm of battery cell 10. That is, at time t3, both the temperature Tw of heat exchange medium W and the temperature Tm (Tm3) of battery cell 10 are at the first temperature T1. When the temperature Tw of heat exchange medium W reaches the first temperature T1, the battery cell 10 can be heated through the heat exchange medium W.

[0133] At time t3, the power supply (discharge) E1 from the battery unit 10 to the heater 40 is stopped. Additionally, at time t3, the power supply E2 from the external power source 70 to the heater 40 is maintained at a level capable of keeping the heat exchange medium W warm. At the same time, at time t3, the external charging C of the battery unit 10 at a high rate by the external power source 70 is restarted.

[0134] At time t3, the temperature Tm (Tm3) of the battery unit 10 has risen to a certain extent. Therefore, even if the battery unit 10 is externally charged (C) at a high rate by the external power source 70, it is difficult for the battery unit 10 to deteriorate at a high rate. Moreover, external charging C at a higher rate (faster) can be performed, so the rate of increase in the temperature Tm of the battery unit 10 can be increased.

[0135] At time t4, the temperature Tm of the battery unit 10 rises to Tm4. At this time, the internal resistance R of the battery unit 10 decreases to saturation (refer to Figure 5 ). That is, at time t4, the temperature Tm (Tm4) of the battery unit 10 is the second temperature T2. At time t4, the heat exchange mode is switched from the adiabatic mode (refer to Figure 3 ) to the heat transfer mode (refer to Figure 4 ). Thereby, the temperature increase of the battery unit 10 through the heat exchange medium W is started.

[0136] (Method for increasing the temperature of the battery unit and the heat exchange medium)

[0137] Figure 11 It is a flowchart showing an example of the control method of the battery unit temperature management device 1, showing until the start of the temperature increase of the battery unit 10 through the heat exchange medium W. First, in step S1, the temperature Tw of the heat exchange medium W is detected by the medium temperature sensor 35. Additionally, in step S1, the temperatures Tm (TmA, TmB, TmC, TmD) of the respective battery units 10 (the first battery unit 10A, the second battery unit 10B, the third battery unit 10C, and the fourth battery unit 10D) are detected by the respective battery temperature sensors 20 (the first battery temperature sensor 20A, the second battery temperature sensor 20B, the third battery temperature sensor 20C, and the fourth battery temperature sensor 20D).

[0138] Next, in step S2, it is determined whether the temperature Tm of each battery unit 10 is less than the specified temperature Tr (Tm < Tr). If Tm < Tr, proceed to step S3. If Tm ≥ Tr, since there is no need to increase the temperature (preheat) of the battery unit 10, return to "Start".

[0139] Next, in step S3, each variable mechanism 50 (first variable mechanism 50A, second variable mechanism 50B, third variable mechanism 50C, and fourth variable mechanism 50D) corresponding to each battery cell 10 is controlled so that the heat exchange mode is the adiabatic mode (refer to Figure 3 ). Specifically, the restraining forces F (FA, FB, FC, FD) generated by the electromagnetic solenoids 52 of each variable mechanism 50 are minimized, so that the electromagnetic solenoids 52 are maximally in the pulling direction.

[0140] Next, in step S4, the pump 31 is operated to circulate the heat exchange medium W in the flow path 30.

[0141] Next, in step S5, the power supply E1 from each battery cell 10 to the heater 40 is started. At this time, the power supply E1 to the heater 40 is performed in the order of the first battery cell 10A, the second battery cell 10B, the third battery cell 10C, and the fourth battery cell 10D.

[0142] Next, in step S6, it is determined whether the temperature Tw of the heat exchange medium W is above the temperature Tm of the battery cell 10 (i.e., the first temperature T1) (Tw≥Tm(T1)). If Tw≥Tm(T1), proceed to step S7. If Tw<Tm(T1), return to step S5.

[0143] Next, in step S7, it is determined whether the temperature Tm of the battery cell 10 is above the second temperature T2 at which its internal resistance R has decreased to saturation (Tm≥T2). If Tm≥T2, proceed to step S8, stop the power supply E1 from the battery cell 10 to the heater 40, so that the heater 40 stops, and proceed to step S10. If Tm<T2, proceed to step S9, and while maintaining the power supply E1 from the battery cell 10 to the heater 40 at a level that can keep the heat exchange medium W warm, proceed to step S10.

[0144] Figure 12 It is a flowchart showing an example of the control method of the battery cell temperature management device 1, indicating the temperature rise homogenization between the battery cells 10.

[0145] In step S10, the heat exchange mode is switched from the adiabatic mode to the heat transfer mode (refer to Figure 4)。Specifically, the electromagnetic solenoids 52 of the variable mechanisms 50 are extended to increase the restraining force F. At this time, the restraining force FD generated by the fourth variable mechanism 50D is maximized (the electromagnetic solenoid 52 is extended to the maximum extent). Moreover, the magnitudes of the restraining forces F generated by the variable mechanisms 50 (50A, 50B, 50C, 50D) are set such that FD > FC > FB > FA. That is, in the order of the fourth battery unit 10D, the third battery unit 10C, the second battery unit 10B, and the first battery unit 10A, the heat transfer capacity with the heat exchange medium W becomes larger, and it is easier to be heated up.

[0146] Here, the heater 40 is disposed on the upstream side of the flow path 30 compared to the battery units 10 and is shared among the plurality of battery units 10. That is, the control device 60 controls the variable mechanisms 50 such that the heat transfer capacity between the battery unit 10 (e.g., the fourth battery unit 10D) far from the shared heater 40 (disposed on the downstream side) and the heat exchange medium W is larger than the heat transfer capacity between the battery unit 10 (e.g., the first battery unit 10A) close to the shared heater 40 (disposed on the upstream side) and the heat exchange medium W.

[0147] Next, in step S11, it is determined whether there is a deviation in the temperature Tm (TmA, TmB, TmC, TmD) of each battery unit 10. The allowable range of the deviation of the temperature Tm can be set to, for example, a specified temperature difference (e.g., 2 to 3 °C) between the maximum temperature and the minimum temperature. If it is determined that there is a deviation in the temperature Tm, the process proceeds to step S12. If it is determined that there is no deviation in the temperature Tm, the process proceeds to step S13.

[0148] Next, in step S12, while maintaining the restraining force FD generated by the fourth variable mechanism 50D at the maximum, the restraining forces FA, FB, FC generated by the other variable mechanisms 50A, 50B, 50C are adjusted to adjust the heat transfer capacity between the battery units 10A, 10B, 10C, 10D and the heat exchange medium W. Then, the process returns to step S11.

[0149] Next, in step S13, it is determined whether the temperature Tm (TmA, TmB, TmC, TmD) of the battery units 10 (10A, 10B, 10C, 10D) is equal to or higher than a specified temperature Tr (Tm ≥ Tr). If Tm < Tr, the process proceeds to step S14. If Tm ≥ Tr, the process proceeds to step S15.

[0150] Next, in step S14, it is determined again whether the temperature Tw of the heat exchange medium W is above the temperature Tm of the battery cell 10 (i.e., the first temperature T1) (Tw≥Tm(T1)). If Tw≥Tm(T1), the process returns to step S11. If Tw<Tm(T1), the process returns to step S9.

[0151] Next, in step S15, the binding forces F generated by the respective variable mechanisms 50 are made uniform. That is, FA = FB = FC = FD. Then, it reaches "Return".

[0152] (Function and effect of the first embodiment)

[0153] As described above, according to the present embodiment, when the heat exchange medium W is heated by the heater 40, in the case where the temperature Tw of the heat exchange medium W does not reach the first temperature T1 equal to the temperature Tm of the battery cell 10, the heat transfer capacity between the battery cell 10 and the heat exchange medium W is reduced by the control of the variable mechanism 50 by the control device 60. Therefore, the heat transfer from the battery cell 10 to the heat exchange medium W is suppressed, and thus the temperature rise delay of the battery cell 10 can be suppressed.

[0154] Moreover, after the temperature Tw of the heat exchange medium W reaches the first temperature T1 equal to the temperature Tm of the battery cell 10, the heat transfer capacity between the battery cell 10 and the heat exchange medium W is increased by the control of the variable mechanism 50 by the control device 60. At this time, since the temperature Tw of the heat exchange medium W is already higher than the temperature Tm of the battery cell 10 (the first temperature T1), even if the heat transfer capacity between the battery cell 10 and the heat exchange medium W is increased, there is almost no heat transfer from the battery cell 10 to the heat exchange medium W, but rather the heat transfer from the heat exchange medium W to the battery cell 10 is promoted.

[0155] In this way, by changing the heat transfer capacity between the battery cell 10 and the heat exchange medium W before and after the temperature Tw of the heat exchange medium W reaches the first temperature T1 equal to the temperature Tm of the battery cell 10, the battery cell 10 can be quickly heated.

[0156] Moreover, before and after the temperature Tw of the heat exchange medium W reaches the first temperature T1, the heat exchange mode is switched from the adiabatic mode to the heat transfer mode, whereby the temperature rise of the battery cell 10 can be accelerated more simply.

[0157] However, when the internal resistance R of the battery cell 10 is high, the capacity of the battery cell 10 cannot be fully utilized; for example, sometimes it is impossible to drive the motor using the battery cell 10. Here, as the battery cell 10 charges and discharges, it generates internal heat and its temperature rises. The internal resistance R of the battery cell 10 decreases as its temperature rises, and it saturates when the temperature Tm of the battery cell 10 reaches a second temperature T2 (refer to...). Figure 5 ).

[0158] Therefore, in order to fully utilize the capabilities of the battery cell 10, it is preferable to use the internal heat generated by the battery cell 10 to rapidly raise its temperature Tm to the second temperature T2. Furthermore, in order to effectively heat the battery cell 10, it is preferable to rapidly raise the temperature Tw of the heat exchange medium W to the first temperature T1.

[0159] Therefore, by considering whether the heat exchange medium W has reached the first temperature T1 (Tm) and whether the battery cell 10 has reached the second temperature T2, the temperature of the battery cell 10 and the heat exchange medium W can be effectively increased.

[0160] According to the first heating mode P1 (refer to...) Figure 7 Since the temperature Tw of the heat exchange medium W has reached the first temperature T1 (Tm), by switching the heat exchange mode from the adiabatic mode to the heat transfer mode, the temperature of the battery cell 10 can be effectively increased by promoting the heat transfer from the heat exchange medium W to the battery cell 10.

[0161] On the other hand, since the temperature Tm of the battery cell 10 has already reached the second temperature T2, there is no need to further supply power (discharge) from the battery cell 10 to the heater 40 in order to reduce the internal resistance R of the battery cell 10. Therefore, by stopping the power supply E1 from the battery cell 10 to the heater 40, unnecessary power consumption of the battery cell 10 can be eliminated.

[0162] According to the second heating mode P2 (refer to...) Figure 8 Similarly, since the temperature Tw of the heat exchange medium W has reached the first temperature T1 (Tm), by switching the heat exchange mode from the adiabatic mode to the heat transfer mode, the temperature of the battery cell 10 can be effectively increased by promoting the heat transfer from the heat exchange medium W to the battery cell 10.

[0163] On the other hand, since the temperature Tm of the battery cell 10 has not reached the second temperature T2, it is necessary to continuously maintain the power supply (discharge) E1 from the battery cell 10 to the heater 40 with the aim of reducing the internal resistance R of the battery cell 10. However, as described above, the heat transfer mode promotes the thermal movement from the heat exchange medium W to the battery cell 10, so the power supply E1 from the battery cell 10 to the heater 40 can be reduced compared to before the temperature Tw of the heat exchange medium W reaches the first temperature T1 (Tm). Thus, it is possible to raise the temperature Tm of the battery cell 10 to the second temperature T2 while minimizing the power consumption of the battery cell 10.

[0164] According to the third heating mode P3 (refer to...) Figure 9 Since the temperature Tm of the battery cell 10 has already reached the second temperature T2, there is no need to further supply power (discharge) from the battery cell 10 to the heater 40 in order to reduce the internal resistance R of the battery cell 10.

[0165] On the other hand, since the temperature Tw of the heat exchange medium W has not reached the first temperature T1 (Tm), it is necessary to maintain the heat exchange mode in an adiabatic mode while continuing to supply power to the heater 40 from the battery cell 10 or other power sources. Therefore, power supply E2 from the external power source 70 to the heater 40 is initiated. As a result, power supply E1 from the battery cell 10 to the heater 40 can be suppressed or stopped. In this way, by using the external power source 70, the temperature Tw of the heat exchange medium W can be raised to the first temperature T1 (Tm) while suppressing the power consumption of the battery cell 10.

[0166] The heat transfer capacity between the battery cell 10 and the heat exchange medium W can be easily varied by means of a variable mechanism 50, which includes a heat transfer element 51 and an electromagnetic solenoid (area change mechanism) 52.

[0167] The heat exchange medium W that is in contact with a battery cell 10 (e.g., the fourth battery cell 10D) that is far from the common heater 40 (located downstream) tends to have a lower temperature Tm than the heat exchange medium W that is in contact with a battery cell 10 (e.g., the first battery cell 10A) that is close to the common heater 40 (located upstream).

[0168] Therefore, for battery cells 10 that are farther away from the common heater 40, the heat transfer capacity with the heat exchange medium W is improved compared to battery cells 10 that are closer to the common heater 40, thereby facilitating heat exchange between the battery cells 10 and the heat exchange medium W. As a result, multiple battery cells 10 can experience an equal temperature rise regardless of their distance from the common heater 40 (whether they are located upstream or downstream).

[0169] (A variation of the first embodiment)

[0170] Hereinafter, variations of the first embodiment will be described. Furthermore, structures identical to those in the above embodiment will be labeled with the same symbols, and detailed descriptions will be omitted.

[0171] In the above embodiment, power supply E1 to the common heater 40 is performed in the order of first battery unit 10A, second battery unit 10B, third battery unit 10C, and fourth battery unit 10D, but it is not limited to this. The control device 60 may also alternately supply power to the common heater 40 from at least a portion of the battery units 10.

[0172] For example, power can be supplied alternately to the common heater 40 from the first battery cell 10A and the second battery cell 10B among the multiple battery cells 10. That is, power can be supplied to the common heater 40 from the first battery cell 10A, then from the second battery cell 10B, and then from the first battery cell 10A again. Alternatively, power can be supplied alternately to the common heater 40 from all the battery cells 10A, 10B, 10C, and 10D.

[0173] This promotes internal heating of the battery cell 10 and efficiently reduces the internal resistance R of the battery cell 10.

[0174] In the above embodiment, the heater 40 is shared among multiple battery cells 10, but this is not a limitation. Figure 13 As shown, the heat exchange medium W can also be heated by multiple heaters 40 corresponding to the multiple battery cells 10 respectively.

[0175] In this case, the heater 40 has four heaters: a first heater 40A, a second heater 40B, a third heater 40C, and a fourth heater 40D. Each heater 40A, 40B, 40C, and 40D is positioned near the corresponding battery cell 10A, 10B, 10C, and 10D to heat the heat exchange medium W that is in contact with the corresponding battery cell 10A, 10B, 10C, and 10D.

[0176] In addition, the medium temperature sensor 35 has four sensors: a first medium temperature sensor 35A, a second medium temperature sensor 35B, a third medium temperature sensor 35C, and a fourth medium temperature sensor 35D. Each of the medium temperature sensors 35A, 35B, 35C, and 35D is disposed near the corresponding battery cell 10A, 10B, 10C, and 10D to detect the heat exchange medium W in contact with the corresponding battery cell 10A, 10B, 10C, and 10D.

[0177] When the heat exchange medium W is heated by the heaters 40A, 40B, 40C, and 40D, the control device 60 prevents the heat exchange medium W from circulating in the flow path 30 if the heat exchange medium W has not reached the first temperature T1 (Tm).

[0178] This allows the heat exchange medium W to be rapidly heated to the first temperature T1 (Tm).

[0179] <Second Implementation>

[0180] The second embodiment will now be described. Furthermore, structures identical to those in the embodiments described above will be labeled with the same symbols, and detailed descriptions will be omitted.

[0181] Figure 14 This is a schematic structural diagram of the battery cell temperature management device 1 according to the second embodiment. In this embodiment, the heater 40 is not operational. Furthermore, the heat exchange medium W in the flow path 30 passes through the heat exchange flow path 30B and is cooled by the heat exchanger 34. The temperature Tw of the heat exchange medium W is lower than the temperature Tm of the battery cell 10 due to cooling by the heat exchanger 34. The heat exchange medium W serves as a cooling medium for cooling each battery cell 10.

[0182] The heat exchange medium W exchanges heat with each of the battery cells 10 in the order of first battery cell 10A, second battery cell 10B, third battery cell 10C, and fourth battery cell 10D from upstream to downstream of the flow path 30. Here, each time the heat exchange medium W exchanges heat with each of the battery cells 10 sequentially from upstream to downstream, the temperature Tw of the heat exchange medium W gradually increases. That is, each time the heat exchange medium W exchanges heat with each of the battery cells 10 sequentially from upstream to downstream, the temperature Tw of the heat exchange medium W gradually approaches the temperature Tm of the battery cell 10.

[0183] Therefore, the downstream battery cell 10 (e.g., the fourth battery cell 10D) is less likely to exchange heat with the heat exchange medium W compared to the upstream battery cell (e.g., the first battery cell 10A). Consequently, the temperatures Tm of each battery cell 10 deviate from each other.

[0184] In this embodiment, the temperature Tm deviation among multiple battery cells 10 is suppressed by the method shown below. Especially when the battery cells 10 are subjected to high-rate charging and discharging, fine temperature management is required (see [reference]). Figure 6 Therefore, it is important to suppress the temperature Tm deviation between multiple battery cells 10.

[0185] Figure 15 This is a flowchart illustrating an example of the control method of the battery cell temperature management device 1. First, in step S1', it is determined whether there is a requirement for high-rate charging and discharging of the battery cell 10. If it is determined that there is a requirement for high-rate charging and discharging, the process proceeds to step S2'. If it is determined that there is no requirement for high-rate charging and discharging (i.e., low-rate charging and discharging), the process returns to "Start" since fine-grained temperature management is not required. Furthermore, whether there is a requirement for high-rate charging and discharging can be determined based on historical data such as the current / voltage of the battery cell 10.

[0186] Next, in step S2', the control device 60 controls the change in the heat transfer capacity between the battery cell 10 and the heat exchange medium W generated by each variable mechanism 50 for each battery cell 10, so as to reduce the temperature difference between the battery cells 10. Specifically, the control device 60 makes the heat transfer capacity between the battery cell 10 disposed on the upstream side of the flow direction (e.g., the first battery cell 10A) and the heat exchange medium W smaller than the heat transfer capacity between the battery cell 10 disposed on the downstream side of the flow direction (e.g., the fourth battery cell 10D) and the heat exchange medium W.

[0187] Furthermore, the control device 60 maximizes the heat transfer capacity between the fourth battery cell 10D, located on the downstream side of the flow direction, and the heat exchange medium W.

[0188] Specifically, the constraint force FD generated by the fourth variable mechanism 50D is maximized. Furthermore, the magnitudes of the constraint forces F generated by each variable mechanism 50 (50A, 50B, 50C, 50D) are set as FD>FC>FB>FA. That is, the heat transfer capacity between the fourth battery unit 10D, the third battery unit 10C, the second battery unit 10B, and the first battery unit 10A increases, making them easier to cool. Then, proceed to step S3'.

[0189] Next, in step S3', it is determined whether the temperature TmD of the fourth battery cell 10D detected by the fourth battery temperature sensor 20D is within the specified temperature range Ts±α. The specified temperature range Ts±α is included within the target management temperature B during high-rate charging and discharging (refer to...). Figure 6 In the range, Ts is, for example, 45°C. α is, for example, a few degrees below.

[0190] In step S3', if it is determined that the temperature TmD of the fourth battery cell 10D is not within the specified temperature range Ts±α, then proceed to step S4'. Then, the flow rate of the heat exchange medium W in the flow path 30 is adjusted (increased or decreased) by adjusting the discharge rate of the pump 31, and then the process returns to step S3'. If it is determined that the temperature TmD of the fourth battery cell 10D is within the specified temperature range Ts±α, then proceed to step S5'. Furthermore, since the constraint force FD generated by the fourth variable mechanism 50D is fixed at its maximum, there is no room to adjust (increase or decrease) the constraint force FD.

[0191] Next, in step S5', it is determined whether the temperature TmC of the third battery cell 10C detected by the third battery temperature sensor 20C is within the specified temperature range Ts±α. If it is determined that the temperature TmC of the third battery cell 10C is not within the specified temperature range Ts±α, then proceed to step S6'. Then, the constraint force FC generated by the third variable mechanism 50C is adjusted (increased or decreased), and then the process returns to step S3'. If it is determined that the temperature TmC of the third battery cell 10C is within the specified temperature range Ts±α, then proceed to step S7'.

[0192] Next, in step S7', it is determined whether the temperature TmB of the second battery cell 10B detected by the second battery temperature sensor 20B is within the specified temperature range Ts±α. If it is determined that the temperature TmB of the second battery cell 10B is not within the specified temperature range Ts±α, then proceed to step S8'. Then, the constraint force FB generated by the second variable mechanism 50B is adjusted (increased or decreased), and then the process returns to step S3'. If it is determined that the temperature TmB of the second battery cell 10B is within the specified temperature range Ts±α, then proceed to step S9'.

[0193] Next, in step S9', it is determined whether the temperature TmA of the first battery cell 10A detected by the first battery temperature sensor 20A is within the specified temperature range Ts±α. If it is determined that the temperature TmA of the first battery cell 10A is not within the specified temperature range Ts±α, then proceed to step S10'. Then, the constraint force FA generated by the first variable mechanism 50A is adjusted (increased or decreased), and then the process returns to step S3'. If it is determined that the temperature TmA of the first battery cell 10A is within the specified temperature range Ts±α, then the process returns to "return".

[0194] In this way, the control device 60 adjusts the heat transfer capacity between each battery cell 10 and the heat exchange medium W based on the temperature Tm of each battery cell 10 detected by each battery temperature sensor 20. For example, the control device 60 reduces the heat transfer capacity between the high-temperature battery cell 10 (with a large temperature difference from the heat exchange medium W) and the heat exchange medium W, or increases the heat transfer capacity between the low-temperature battery cell 10 (with a small temperature difference from the heat exchange medium W) and the heat exchange medium W.

[0195] (Effects of the second embodiment)

[0196] According to this embodiment, each variable mechanism 50, arranged in a manner corresponding to each battery cell 10, causes a variation in the heat transfer capacity between each battery cell 10 and the heat exchange medium W. Furthermore, the control device 60 controls the variation in heat transfer capacity generated by each variable mechanism 50 for each battery cell 10, thereby reducing the temperature difference between the battery cells 10. As a result, temperature deviations Tm between the multiple battery cells 10 can be suppressed.

[0197] The heat exchange medium W that contacts the battery cell 10 (e.g., the first battery cell 10A) located upstream in the flow direction of the flow path 30 tends to have a larger temperature difference with the battery cell 10 located downstream in the flow direction of the flow path 30 (e.g., the fourth battery cell 10D). In other words, the battery cell 10 located upstream is more likely to exchange heat with the heat exchange medium W than the battery cell 10 located downstream.

[0198] Therefore, by adjusting the heat transfer capacity using each variable mechanism 50, the battery cell 10 disposed on the upstream side is less likely to exchange heat with the heat exchange medium W compared to the battery cell 10 disposed on the downstream side. As a result, temperature Tm deviations among the multiple battery cells 10 disposed along the flow direction of the flow path 30 can be suppressed.

[0199] The heat exchange medium W that contacts the battery cell 10 (e.g., the fourth battery cell 10D) located downstream in the flow direction of the flow path 30 tends to have a smaller temperature difference with the battery cell 10 compared to the heat exchange medium W that contacts the battery cell 10 (e.g., the first battery cell 10A) located upstream in the flow direction of the flow path 30. That is, the fourth battery cell 10D located at the downstream end is more difficult to exchange heat with the heat exchange medium W compared to all the other battery cells 10A, 10B, and 10C located upstream.

[0200] Therefore, by maximizing the heat transfer capacity (constraint force F4) between the fourth battery cell 10D located on the downstream side and the heat exchange medium W, heat exchange between the fourth battery cell 10D located on the downstream side and the heat exchange medium W can be facilitated as easily as possible. As a result, the temperature change of the fourth battery cell 10D located on the downstream side can be minimized without increasing the flow rate (discharge rate of pump 31) of the heat exchange medium W flowing in the flow path 30.

[0201] The heat transfer capacity between the battery cell 10 and the heat exchange medium W can be easily varied by means of a variable mechanism 50, which includes a heat transfer element 51 and an electromagnetic solenoid (area change mechanism) 52.

[0202] Since the heat transfer capacity is adjusted based on the temperature Tm of each battery cell 10 detected by each battery temperature sensor 20, the temperature Tm of each battery cell 10 can be adjusted more precisely.

[0203] (A variation of the second embodiment)

[0204] In the above embodiment, the control device 60 makes the heat transfer capacity between the battery cell 10 disposed on the upstream side of the flow direction and the heat exchange medium W smaller than that between the battery cell 10 disposed on the downstream side of the flow direction and the heat exchange medium W, but it is not limited to this.

[0205] For example, if a heater is arranged only near the second battery cell 10B in the plurality of battery cells 10, the second battery cell 10B is less likely to exchange heat with the heat exchange medium W (be cooled) compared to the other battery cells 10A, 10C, 10D.

[0206] In this case, it is sufficient to ensure that the heat transfer capacity between the second battery cell 10B and the heat exchange medium W is greater than that between the other battery cells 10A, 10C, and 10D and the heat exchange medium W. At this time, the control device 60 ensures that the heat transfer capacity between the second battery cell 10B, located upstream in the flow direction, and the heat exchange medium W is greater than that between the battery cells 10C and 10D, located downstream in the flow direction, and the heat exchange medium W.

[0207] In the above embodiment, the heat exchange medium W is exemplified as being used to cool each battery cell 10 through the heat exchange flow path 30B, but this is not a limitation. The heat exchange medium W can also be used to heat each battery cell 10 through the bypass flow path 30A. Furthermore, in this case, the heater 40 operates in the flow path 30.

[0208] (Other implementation methods)

[0209] The present invention has been described above through preferred embodiments, but such description is not limiting and various changes can be made.

[0210] The area changing mechanism is not limited to the electromagnetic solenoid 52; for example, it can also be constituted by a mechanical piston-cylinder mechanism. In the above embodiment, the corrugated plate-shaped heat transfer element 51 has a heat transfer surface 51a for heat exchange with the heat exchange medium W, but it is not limited to this. It is also possible to prepare a heat transfer element independent of the corrugated plate-shaped heat transfer element 51, and to provide a heat transfer surface for heat exchange with the heat exchange medium W on this independent heat transfer element.

[0211] (Industrial utilization)

[0212] This invention can be applied to battery cell temperature management devices, and is therefore extremely useful and has high industrial applicability.

Claims

1. A battery cell temperature management device, characterized in that, have: A battery cell that is capable of being charged and discharged; A heater that operates by a power supply from the battery cell and heats the heat exchange medium that exchanges heat with the battery cell; A variable mechanism that allows the heat transfer capacity between the battery cell and the heat exchange medium to vary; as well as A control device that controls the heating of the heat exchange medium by the heater and the variation in heat transfer capacity caused by the variable mechanism. When the heat exchange medium is heated using the heater, if the temperature of the heat exchange medium does not reach a first temperature equal to the temperature of the battery cell, the control device reduces the heat transfer capacity compared to when the temperature of the heat exchange medium reaches the first temperature. The battery cell is composed of multiple battery cells arranged in an array. The variable mechanism includes: A corrugated heat transfer element disposed between the battery cells; as well as An electromagnetic solenoid, which is an area-changing mechanism that changes the shape of the heat transfer element from a corrugated plate shape to a flat plate shape by pressing the battery cell. When the electromagnetic solenoid is controlled in a pulling direction opposite to the pressing direction, the heat transfer element changes from a flat plate shape to a corrugated plate shape, thereby forming an air layer between the heat transfer element and the battery cell. During the period when the temperature of the heat exchange medium has not reached the first temperature, the control device controls the electromagnetic solenoid in the pulling direction, causing the heat transfer element to change from the flat plate shape to the corrugated plate shape, thereby forming the air layer and reducing the heat transfer capacity.

2. The battery cell temperature management device according to claim 1, characterized in that, The variable mechanism can switch the heat exchange mode between the battery cell and the heat exchange medium to an adiabatic mode that inhibits heat exchange and a heat transfer mode that promotes heat exchange. When the heat exchange medium is heated using the heater, if the temperature of the heat exchange medium does not reach the first temperature, the control device sets the heat exchange mode to the adiabatic mode; on the other hand, if the temperature of the heat exchange medium reaches the first temperature, the control device sets the heat exchange mode to the heat transfer mode.

3. The battery cell temperature management device according to claim 2, characterized in that, The control device controls the heating of the heat exchange medium by the heater and the change in heat transfer capacity generated by the variable mechanism based on whether the heat exchange medium has reached the first temperature and whether the battery cell has reached the second temperature at which the internal resistance of the battery cell decreases to saturation.

4. The battery cell temperature management device according to claim 3, characterized in that, When the heat exchange medium is heated by the heater, if the battery cell reaches the second temperature at the moment the heat exchange medium reaches the first temperature, the control device stops the power supply from the battery cell to the heater and switches the heat exchange mode from the adiabatic mode to the heat transfer mode.

5. The battery cell temperature management device according to claim 3, characterized in that, When the heat exchange medium is heated by the heater, if the battery cell has not reached the second temperature when the heat exchange medium reaches the first temperature, the control device does not stop the power supply from the battery cell to the heater and reduces the power supply compared to the power supply before the heat exchange medium reaches the first temperature, and switches the heat exchange mode from the adiabatic mode to the heat transfer mode.

6. The battery cell temperature management device according to claim 3, characterized in that, When the heat exchange medium is heated by the heater, if the heat exchange medium has not reached the first temperature when the battery cell reaches the second temperature, the control device maintains the heat exchange mode in the adiabatic mode while starting to supply power to the heater from an external power source.

7. The battery cell temperature management device according to claim 1, characterized in that, have: Multiple of the aforementioned battery cells; A plurality of the variable mechanisms are arranged in a manner corresponding to each of the battery cells; and A flow path is provided for the heat exchange medium to circulate through each of the battery cells. The heat exchange medium is heated by the heater disposed in the flow path and shared among the plurality of battery cells. The control device ensures that the heat transfer capacity between the battery cell farther from the shared heater and the heat exchange medium is greater than the heat transfer capacity between the battery cell closer to the shared heater and the heat exchange medium.

8. The battery cell temperature management device according to claim 1, characterized in that, have: Multiple of the aforementioned battery cells; A plurality of the variable mechanisms are arranged in a manner corresponding to each of the battery cells; and A flow path is provided for the heat exchange medium to circulate through each of the battery cells. The heat exchange medium is heated by the heater disposed in the flow path and shared among the plurality of battery cells. The control device alternately supplies power from at least a portion of the battery cells to the shared heater.

9. The battery cell temperature management device according to claim 1, characterized in that, have: Multiple of the aforementioned battery cells; A plurality of the variable mechanisms are arranged in a manner corresponding to each of the battery cells; and A flow path is provided for the heat exchange medium to circulate through each of the battery cells. The heat exchange medium is heated by a plurality of heaters corresponding to the plurality of battery cells. The control device controls the circulation of the heat exchange medium in the flow path. When the heat exchange medium is heated using the heaters, the control device prevents the heat exchange medium from circulating in the flow path if the heat exchange medium does not reach the first temperature.

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