Battery system, method for controlling the battery system, and program

Abstract

To optimize the entire system by accurately reflecting the changes in heat transfer characteristics caused by changes in the contact pressure between the battery cell and the elastic component in the temperature control of the battery cell. [Solution] A battery system 1 comprising a battery cell 21 that expands and contracts according to the remaining charge, and an elastic member 22 adjacent to the battery cell 21 whose contact pressure with the battery cell 21 changes according to the expansion and contraction of the battery cell 21, wherein the battery system 1 comprises a temperature control unit 37 that heats or cools the battery cell 21 based on a preset reference temperature, and a charge level acquisition unit 33 that acquires the state of the remaining charge of the battery cell 21, wherein the temperature control unit 37 sets the heating stop temperature, which stops heating when the remaining charge is above a predetermined level, higher than the heating stop reference temperature, which is the reference temperature for stopping heating, and sets the cooling start temperature, which starts cooling, higher than the cooling start reference temperature, which is the reference temperature for starting cooling.

Description

Technical Field

[0001] The present invention relates to a battery system, a control method for a battery system, and a program.

Background Art

[0002] In recent years, research and development on secondary batteries that contribute to energy efficiency have been carried out to ensure that more people can access affordable, reliable, sustainable and advanced energy.

[0003] Conventionally, for batteries used in vehicles and the like, a technology is known that acquires information indicating the state of charge of a battery, which is specified by SOC (State of Charge) indicating the remaining charge level, and performs battery control related to charging and discharging, temperature, and the like. Patent Document 1 and Patent Document 2, for example, describe this type of technology.

[0004] Patent Document 1 adjusts the battery to have a higher temperature when the battery cell is within the SOC range where the cell expands. This is said to eliminate the bias in salt concentration in the electrolyte and suppress deterioration caused by an increase in internal resistance during high-rate charging.

[0005] Patent Document 2 uses the surface pressure of the electrode body, which correlates with the state of charge, as one of the control signals, and determines whether heating is necessary according to the detected surface pressure. This is said to suppress deterioration during high-rate charging and discharging.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of Invention

Problems to be Solved by the Invention

[0007] Incidentally, in all-solid-state batteries where interfacial contact between the solid electrolyte and other layers is important, and in batteries using Li or Si anodes with large expansion amounts, structures in which an elastic member is adjacent to the battery cell have been considered for surface pressure control and expansion absorption. In such structures, the surface pressure on the elastic member of the battery cell changes depending on the charge state, but conventional technology has not been considered from this perspective, and the change in surface pressure leads to a change in the thickness of the elastic member, which affects the thermal conductance. Therefore, there was room for improvement in conventional technology in terms of more accurate temperature control of the battery cell.

[0008] The present invention aims to accurately reflect changes in heat transfer characteristics caused by changes in the contact pressure between the battery cell and the elastic member in the temperature control of the battery cell. Furthermore, it aims to provide a battery system, a control method for the battery system, and a program that can improve the overall efficiency of the system. Ultimately, this contributes to energy efficiency. [Means for solving the problem]

[0009] (1) One aspect of the present invention is a battery system (for example, a battery system 1, described later) comprising: a battery cell (for example, a battery cell 21, described later) that expands and contracts according to the remaining charge; and an elastic member (for example, an elastic member 22, described later) adjacent to the battery cell, the contact pressure with the battery cell changes according to the expansion and contraction of the battery cell, the battery system comprising: a temperature control unit (for example, a temperature control unit 37, described later) that performs heating or cooling of the battery cell based on a preset reference temperature; and a charge level acquisition unit (for example, a charge level acquisition unit 33, described later) that acquires the state of the remaining charge of the battery cell, wherein the temperature control unit sets the heating stop temperature at which heating is stopped to a higher level than the heating stop reference temperature, which is the reference temperature for stopping heating, when the remaining charge is above a predetermined level, and sets the cooling start temperature at which cooling is started to a higher level than the cooling start reference temperature, which is the reference temperature for starting cooling.

[0010] (2) Another aspect of the present invention is a battery system (for example, a battery system 1, described later) comprising: a battery cell that expands and contracts according to the remaining charge (for example, a battery cell 21, described later); and an elastic member (for example, an elastic member 22, described later) adjacent to the battery cell, the contact pressure with the battery cell changes according to the expansion and contraction of the battery cell, the battery system comprising: a temperature control unit (for example, a temperature control unit 37, described later) that performs heating or cooling of the battery cell based on a preset reference temperature; and a charge level acquisition unit (for example, a charge level acquisition unit 33, described later) that acquires the state of the remaining charge of the battery cell, wherein the temperature control unit sets the heating stop temperature at which heating is stopped to a lower temperature than the heating stop reference temperature, which is the reference temperature for stopping heating, when the remaining charge is below a predetermined level, and sets the cooling start temperature at which cooling is started to a lower temperature than the cooling start reference temperature, which is the reference temperature for starting cooling.

[0011] (3) Another aspect of the present invention is a battery system (for example, a battery system 1, described later) comprising: a battery cell that expands and contracts according to the remaining charge (for example, a battery cell 21, described later); and an elastic member (for example, an elastic member 22, described later) adjacent to the battery cell, the contact pressure with the battery cell changes according to the expansion and contraction of the battery cell, the battery system comprising: a temperature control device (for example, a liquid supply device 11, a heating device 12, an air volume adjustment device 13, and a heat dissipation device 16, described later); a temperature control unit (for example, a temperature control unit 37, described later) that performs heating or cooling of the battery cell based on a preset reference capacity of the temperature control device; and a charge level acquisition unit (for example, a charge level acquisition unit 33, described later) that acquires the state of the remaining charge of the battery cell, wherein the temperature control unit sets the heating capacity of the temperature control device to be higher than the heating reference capacity, which is the reference capacity for heating, and sets the cooling capacity of the temperature control device to be lower than the cooling reference capacity, which is the reference capacity for cooling, when the remaining charge is above a predetermined level.

[0012] (4) Another aspect of the present invention is a battery system (for example, a battery system 1, described later) comprising: a battery cell that expands and contracts according to the remaining charge (for example, a battery cell 21, described later); and an elastic member (for example, an elastic member 22, described later) adjacent to the battery cell, the contact pressure with the battery cell changes according to the expansion and contraction of the battery cell, the battery system comprising: a temperature control device (for example, a liquid supply device 11, a heating device 12, an air volume adjustment device 13, and a heat dissipation device 16, described later); a temperature control unit (for example, a temperature control unit 37, described later) that performs heating or cooling of the battery cell based on a preset reference capacity of the temperature control device; and a charge level acquisition unit (for example, a charge level acquisition unit 33, described later) that acquires the state of the remaining charge of the battery cell, wherein the temperature control unit sets the heating capacity of the temperature control device lower than the heating reference capacity, which is the reference capacity for heating, and sets the cooling capacity of the temperature control device higher than the cooling reference capacity, which is the reference capacity for cooling, when the remaining charge is below a predetermined level.

[0013] (5) In the battery system described in (1) or (2) above, the temperature control unit may determine which of a plurality of predetermined regions the remaining charge belongs to, and set the heating stop temperature and the cooling start temperature based on the determination result.

[0014] (6) In the battery system described in (1) or (2) above, the battery system further comprises a surface pressure acquisition unit (for example, a surface pressure acquisition unit 35 described later) that acquires the contact surface pressure between the battery cell and the elastic member, and the temperature control unit may set the heating stop temperature and the cooling start temperature based on the contact surface pressure.

[0015] (7) In the battery system described in (3) or (4) above, the temperature control unit may determine which of a plurality of predetermined regions the remaining charge belongs to, and set the heating capacity and the cooling capacity based on the determination result.

[0016] (8) In the battery system described in (3) or (4) above, the battery system further comprises a surface pressure acquisition unit (for example, a surface pressure acquisition unit 35 described later) that acquires the contact surface pressure between the battery cell and the elastic member, and the temperature control unit may set the heating capacity and the cooling capacity based on the contact surface pressure.

[0017] (9) In the battery system described in (1) or (2) above, the battery system further comprises a vehicle state acquisition unit (for example, a vehicle state acquisition unit 36 ​​described later) for acquiring the vehicle state, and the temperature control unit may set the heating stop temperature and the cooling start temperature based on the vehicle state.

[0018] (10) In the battery system described in (3) or (4) above, the battery system further comprises a vehicle state acquisition unit (for example, a vehicle state acquisition unit 36 ​​described later) for acquiring the vehicle state, and the temperature control unit may set the heating capacity and the cooling capacity based on the vehicle state.

[0019] (11) In the battery system described in (3) or (4) above, the temperature control device includes a liquid delivery device (for example, a liquid delivery device 11 described later) that controls the flow rate of the heat transfer medium supplied to the battery cells, and the temperature control unit may change the flow rate of the heat transfer medium by the liquid delivery device based on the remaining charge.

[0020] (12) In the battery system described in (3) or (4) above, the temperature control device includes a heat dissipation device (for example, a heat dissipation device 16 described later) for cooling the heat transfer medium supplied to the battery cells, and the temperature control unit may change the cooling setting of the heat dissipation device based on the remaining charge.

[0021] (13) In the battery system described in (3) or (4) above, the temperature control device includes a heating device (for example, a heating device 12 described later) that heats the heat transfer medium supplied to the battery cells, and the temperature control unit may change the heating setting of the heating device based on the remaining charge.

[0022] (14) The battery system according to the above (3) or (4), wherein the temperature adjustment device may include a heat rejection device (for example, heat rejection device 16 described later) disposed in a circuit through which a heat medium supplied to the battery cell flows, and an air volume adjustment device (for example, air volume adjustment device 13 described later) capable of adjusting the amount of air supplied to the heat rejection device, and the temperature control unit may control the air volume adjustment device based on the remaining charge level.

[0023] (15) The battery system according to any one of the above (1) to (14), wherein the battery cell may be an all-solid-state battery cell.

[0024] (16) The battery system according to any one of the above (1) to (15), wherein the negative electrode of the battery cell may contain Li metal or a Li alloy.

[0025] (17) The battery system according to any one of the above (1) to (15), wherein the negative electrode of the battery cell may contain Si or a Si alloy.

[0026] (18) Another aspect of the present invention is a control method for a battery system (for example, battery system 1 described later) including a battery cell (for example, battery cell 21 described later) that expands and contracts according to the remaining charge level, and an elastic member (for example, elastic member 22 described later) that is adjacent to the battery cell and whose contact surface pressure with the battery cell changes according to the expansion and contraction of the battery cell, the method comprising: a temperature control step of performing heating or cooling of the battery cell based on a preset reference temperature; and a remaining charge level acquisition step of acquiring the state of the remaining charge level of the battery cell. In the temperature control step, when the remaining charge level is equal to or higher than a predetermined value, the heating stop temperature for stopping the heating is set higher than the heating stop reference temperature that is the reference temperature for stopping heating, and the cooling start temperature for starting the cooling is set higher than the cooling start reference temperature that is the reference temperature for starting cooling.

[0027] (19) Another aspect of the present invention is a control method for a battery system (for example, a battery system 1 described later) including a battery cell that expands and contracts according to the remaining charge (for example, a battery cell 21 described later) and an elastic member (for example, an elastic member 22 described later) adjacent to the battery cell, the contact pressure with the battery cell changes according to the expansion and contraction of the battery cell, the control method comprising: a temperature control step in which heating or cooling of the battery cell is performed based on a preset reference temperature; and a charge level acquisition step in which the state of the remaining charge of the battery cell is acquired, wherein in the temperature control step, when the remaining charge is below a predetermined level, the heating stop temperature at which heating is stopped is set lower than the heating stop reference temperature, which is the reference temperature for stopping heating, and the cooling start temperature at which cooling is started is set lower than the cooling start reference temperature, which is the reference temperature for starting cooling.

[0028] (20) Another aspect of the present invention is a control method for a battery system (for example, a battery system 1 described later) including a battery cell that expands and contracts according to the remaining charge (for example, a battery cell 21 described later), an elastic member adjacent to the battery cell and whose contact pressure with the battery cell changes according to the expansion and contraction of the battery cell (for example, an elastic member 22 described later), and a temperature control device (for example, a liquid supply device 11, a heating device 12, an air volume adjustment device 13, and a heat dissipation device 16 described later), comprising a temperature control step in which heating or cooling of the battery cell is performed based on a preset reference capacity of the temperature control device, and a charge remaining acquisition step in which the state of the remaining charge of the battery cell is acquired, wherein in the temperature control step, if the remaining charge is above a predetermined level, the heating capacity of the temperature control device is set higher than the heating reference capacity, which is the reference capacity for heating, and the cooling capacity of the temperature control device is set lower than the cooling reference capacity, which is the reference capacity for cooling.

[0029] (21) Another aspect of the present invention is a control method for a battery system (for example, a battery system 1 described later) including a battery cell that expands and contracts according to the remaining charge (for example, a battery cell 21 described later), an elastic member adjacent to the battery cell and whose contact pressure with the battery cell changes according to the expansion and contraction of the battery cell (for example, an elastic member 22 described later), and a temperature control device (for example, a liquid supply device 11, a heating device 12, an air volume adjustment device 13, and a heat dissipation device 16 described later), comprising a temperature control step in which heating or cooling of the battery cell is performed based on a preset reference capacity of the temperature control device, and a charge remaining amount acquisition step in which the state of the remaining charge of the battery cell is acquired, wherein in the temperature control step, when the remaining charge is below a predetermined level, the heating capacity of the temperature control device is set lower than the heating reference capacity, which is the reference capacity for heating, and the cooling capacity of the temperature control device is set higher than the cooling reference capacity, which is the reference capacity for cooling.

[0030] (22) Another aspect of the present invention is a program for causing a computer to execute a control method for a battery system (for example, a battery system 1 described later) which includes a battery cell that expands and contracts according to the remaining charge (for example, a battery cell 21 described later) and an elastic member (for example, an elastic member 22 described later) adjacent to the battery cell, the contact pressure with the battery cell changing according to the expansion and contraction of the battery cell, the program comprising: a temperature control step in which the heating of the battery cell is heated or cooled based on a preset reference temperature; and a charge level acquisition step in which the state of the remaining charge of the battery cell is acquired, wherein in the temperature control step, if the remaining charge is above a predetermined level, the heating stop temperature for stopping the heating is set higher than the heating stop reference temperature, which is the reference temperature for stopping the heating, and the cooling start temperature for starting the cooling is set higher than the cooling start reference temperature, which is the reference temperature for starting the cooling.

[0031] (23) Another aspect of the present invention is a program for causing a computer to execute a control method for a battery system (for example, a battery system 1 described later) which includes a battery cell that expands and contracts according to the remaining charge (for example, a battery cell 21 described later) and an elastic member (for example, an elastic member 22 described later) adjacent to the battery cell, the contact pressure with the battery cell changing according to the expansion and contraction of the battery cell, the program comprising: a temperature control step in which the heating of the battery cell is heated or cooled based on a preset reference temperature; and a charge level acquisition step in which the state of the remaining charge of the battery cell is acquired, wherein in the temperature control step, if the remaining charge is below a predetermined level, the heating stop temperature for stopping the heating is set lower than the heating stop reference temperature, which is the reference temperature for stopping the heating, and the cooling start temperature for starting the cooling is set lower than the cooling start reference temperature, which is the reference temperature for starting the cooling.

[0032] (24) Another aspect of the present invention is a program for causing a computer to execute a control method for a battery system (for example, a battery system 1 described later) which includes a battery cell that expands and contracts according to the remaining charge (for example, a battery cell 21 described later), an elastic member adjacent to the battery cell whose contact pressure with the battery cell changes according to the expansion and contraction of the battery cell (for example, an elastic member 22 described later), and a temperature control device (for example, a liquid supply device 11, a heating device 12, an air volume adjustment device 13, and a heat dissipation device 16 described later), the program comprising: a temperature control step in which the heating or cooling of the battery cell is performed based on a preset reference capacity of the temperature control device; and a charge level acquisition step in which the state of the remaining charge of the battery cell is acquired, wherein in the temperature control step, if the remaining charge is above a predetermined level, the heating capacity of the temperature control device is set higher than the heating reference capacity, which is the reference capacity for heating, and the cooling capacity of the temperature control device is set lower than the cooling reference capacity, which is the reference capacity for cooling.

[0033] (25) Another aspect of the present invention is a program for causing a computer to execute a control method for a battery system (for example, a battery system 1 described later) which includes a battery cell that expands and contracts according to the remaining charge (for example, a battery cell 21 described later), an elastic member adjacent to the battery cell whose contact pressure with the battery cell changes according to the expansion and contraction of the battery cell (for example, an elastic member 22 described later), and a temperature control device (for example, a liquid supply device 11, a heating device 12, an air volume adjustment device 13, and a heat dissipation device 16 described later), the program comprising: a temperature control step in which the heating or cooling of the battery cell is performed based on a preset reference capacity of the temperature control device; and a charge level acquisition step in which the state of the remaining charge of the battery cell is acquired, wherein in the temperature control step, if the remaining charge is below a predetermined level, the heating capacity of the temperature control device is set lower than the heating reference capacity, which is the reference capacity for heating, and the cooling capacity of the temperature control device is set higher than the cooling reference capacity, which is the reference capacity for cooling. [Effects of the Invention]

[0034] According to the present invention, by accurately reflecting the change in heat transfer characteristics caused by the change in contact pressure between the battery cell and the elastic member in the temperature control of the battery cell, it is possible to provide a battery system, a control method for the battery system, and a program that lead to improved overall system efficiency. [Brief explanation of the drawing]

[0035] [Figure 1] This is a block diagram of a vehicle equipped with a battery system to which a battery ECU according to one embodiment of the present invention is applied. [Figure 2] This figure shows the chilled water circuit of the battery system according to this embodiment. [Figure 3] This figure schematically shows the battery pack of the battery system according to this embodiment. [Figure 4] This graph shows the relationship between the charge level of the battery cells and the surface pressure applied to the battery cells during discharge and charging in the battery pack of the battery system according to this embodiment. [Figure 5] This graph shows an example of the thermal conductivity of an elastic material. [Figure 6] This graph shows an example of thermal conductance between a battery cell and an elastic member. [Figure 7] This graph shows an example of a current profile in which the current value decreases gradually over time. [Figure 8] Figure 7 is a graph comparing the temperature distribution of battery cells at time t1 when current is applied, under the cases of low SOC and high SOC. [Figure 9] Figure 7 is a graph comparing the temperature distribution of battery cells at time t2 when current is applied, under the cases of low SOC and high SOC. [Figure 10] This figure shows the heating stop temperature and cooling start temperature, which are set according to the State of Charge (SOC) status. [Figure 11] This figure shows the relationship between the State of Charge (SOC) state and the heating stop temperature and cooling start temperature. [Figure 12] This flowchart shows an example of the process for setting the heating and cooling temperature ranges based on the State of Charge (SOC) status. [Figure 13] This flowchart shows another example of the process for setting the heating and cooling temperature ranges based on the State of Charge (SOC) status. [Figure 14] Figure 7 is a graph comparing the temperature distribution of battery cells at time t1 when current is applied, with a standard cooling capacity set and with an enhanced cooling capacity set. [Figure 15] Figure 7 is a graph comparing the temperature distribution of battery cells at time t2 when current is applied, with a standard cooling capacity set and with an enhanced cooling capacity set. [Figure 16] This flowchart shows an example of the process for setting heating and cooling capacities based on the State of Charge (SOC) status. [Figure 17] This flowchart shows another example of the process for setting heating and cooling capacities based on the State of Charge (SOC) status. [Figure 18] This figure shows a modified example of a battery system's chilling circuit. [Modes for carrying out the invention]

[0036] Hereinafter, a battery system 1, a control method for the battery system 1, and a program according to one embodiment of the present invention will be described with reference to the drawings.

[0037] <Overall Structure> Figure 1 is a block diagram of a vehicle equipped with a battery system 1 to which a battery ECU 3 according to one embodiment of the present invention is applied. As shown in Figure 1, the battery system 1 comprises two battery packs 2 connected in series and a battery ECU (Electronic Control Unit) 3. The battery ECU 3 includes a CPU and memory. The functions and operations of each functional unit, which will be described later, are achieved through the cooperation of the CPU, memory, and the program stored in the memory. Note that the configuration of the battery system 1, including the number of battery packs 2 and the connection method, is not limited to the configuration shown in Figure 1.

[0038] The battery pack 2 is a secondary battery unit having multiple battery cells 21. The battery pack 2 is equipped with a battery temperature sensor 41 for detecting the temperature of the battery pack 2 and a battery voltage sensor 42 for detecting the input and output voltages of the battery pack 2. The battery temperature sensor 41 and the battery voltage sensor 42 are connected to the battery ECU 3. The battery temperature sensor 41 and the battery voltage sensor 42 output detection signals to the battery ECU 3.

[0039] Furthermore, a power distribution unit 4 is connected to the battery pack 2. The power distribution unit 4 is connected to the battery pack 2 and also to auxiliary equipment mounted on the vehicle, such as the drive unit 5, charger 6, fluid supply device 11, heating device 12, air volume adjustment device 13 such as AGS (Active Grille Shutter), and heat dissipation device 16. The drive unit 5 has, for example, an electric motor for driving the vehicle. The vehicle runs using the power of this electric motor. The charger 6 has a power converter that receives AC power from an external power supply device (not shown) and converts it into DC power of a predetermined voltage. The battery pack 2 is capable of being charged with power from the external power supply device converted by the charger 6.

[0040] Auxiliary equipment such as the temperature control system, including the liquid supply device 11, heating device 12, air volume adjustment device 13, and heat dissipation device 16, can be operated using power supplied from the battery pack 2.

[0041] Figure 2 shows the chilled water circuit 10 of the battery system 1 according to this embodiment. A liquid supply device 11, a battery pack 2, a heating device 12, a tank 14, and a heat dissipation device 16 are arranged on the chilled water circuit 10 shown in Figure 2.

[0042] The fluid supply device 11 is an electric water pump (EWP) that supplies the heat transfer medium to flow through the chilled water circuit 10. The heating device 12 is a heating heater that heats the heat transfer medium and is an electric heater (ECH) that operates electrically. The heating device 12 may be used, for example, as a heating device for the air conditioning system of a vehicle.

[0043] Tank 14 is a storage device for storing a heat transfer medium. The heat exhaust device 16 is a cooler that cools the heat transfer medium, and is a radiator equipped with an air volume control device 13 such as an AGS. The air volume control device 13 such as an AGS is a shutter device positioned at the point where air is supplied to the radiator, and the amount of air supplied to the heat exhaust device 16 such as a radiator can be adjusted by opening and closing it. By closing the air volume control device 13 such as an AGS, the cooling capacity of the heat exhaust device 16 such as a radiator can be reduced. This improves energy efficiency by avoiding unnecessary cooling and makes the entire system more efficient.

[0044] The heat dissipation device 16 may be a cooling water circulation device that mainly comprises a compressor, evaporator, condenser, and expansion valve. In this case, the cooling capacity of the heat dissipation device 16 can be controlled by adjusting the rotation speed of the compressor, etc.

[0045] Note that the cooling water circuit 10 in Figure 2 is just one example of a configuration for cooling the battery pack 2, and is not limited to the configuration shown in Figure 2. For example, if the battery cell 21 is an all-solid-state battery, the usable temperature range of an all-solid-state battery is wider than that of a battery containing an electrolyte, so the heat dissipation device 16 in the cooling water circuit 10 may be omitted.

[0046] Returning to Figure 1, let's explain the battery ECU 3. The battery ECU 3 is connected to the battery pack 2. The battery ECU 3 controls the charging and discharging power of the battery pack 2. The battery ECU 3 is also connected to the vehicle control device 50. The vehicle control device 50 has multiple ECUs and performs various controls on the operation of the vehicle and auxiliary equipment (temperature control system including the fluid supply device 11, heating device 12, air volume adjustment device 13, and heat dissipation device 16). The vehicle control device 50 outputs signals related to the control of the battery pack 2 to the battery ECU 3.

[0047] The battery ECU3 of this embodiment is a battery control device comprising a battery temperature acquisition unit 31, a battery voltage acquisition unit 32, a charge level acquisition unit 33, a target input / output power setting unit 34, a surface pressure acquisition unit 35, a vehicle status acquisition unit 36, and a temperature control unit 37.

[0048] The battery temperature acquisition unit 31 acquires the temperature of the battery pack 2 based on the detection signal output from the battery temperature sensor 41.

[0049] The battery voltage acquisition unit 32 acquires the input and output voltages of the battery pack 2 based on the detection signal output from the battery voltage sensor 42.

[0050] The charge level acquisition unit 33 acquires the State of Charge (SOC), which indicates the remaining charge level of the battery pack 2 (battery cells 21), based on the temperature of the battery pack 2 acquired by the battery temperature acquisition unit 31 and the input / output voltage of the battery pack 2 acquired by the battery voltage acquisition unit 32.

[0051] The target input / output power setting unit 34 sets the target input / output power of the battery pack 2 based on the control signals for the battery pack 2 output from the vehicle control device 50. The target input / output power setting unit 34 outputs a signal to the battery pack 2 indicating the set target input / output power and controls the input / output power of the battery pack 2 so that it matches the set target input / output power.

[0052] The surface pressure acquisition unit 35 acquires the contact surface pressure between the battery cell 21 and the elastic member 22 based on a detection signal output from, for example, a pressure sensor (not shown) provided in the battery pack 2.

[0053] The vehicle status acquisition unit 36 ​​acquires a vehicle status signal from the vehicle control device 50 that indicates the status of the vehicle. The vehicle status is information that indicates the operating status of the vehicle, such as whether or not it is connected to the power supply and whether or not the vehicle is running.

[0054] The temperature control unit 37 performs temperature control to heat or cool the battery cells 21 based on a reference temperature set in the battery cells 21. Preferably, the temperature control unit 37 performs temperature control of the battery pack 2 based on the State of Charge (SOC) state, which indicates the remaining charge amount calculated by the remaining charge amount acquisition unit 33. The temperature control unit 37 may also perform temperature control of the battery pack 2 based on the vehicle state acquired by the vehicle state acquisition unit 36. Alternatively, the temperature control unit 37 may perform temperature control of the battery pack 2 based on the contact surface pressure between the battery cells 21 and the elastic member 22, which is acquired by the surface pressure acquisition unit 35. Details of the temperature control of the temperature control unit 37 will be described later.

[0055] <Modular structure of battery pack 2> The battery module 20 includes at least a battery cell 21 that expands and contracts in response to charging and discharging, and an elastic member 22 for ensuring surface pressure. The battery module 20 of this embodiment is a structure in which the temperature trend of the battery cell 21 changes in accordance with the change in thermal conductance between the battery cell 21 and the elastic member 22, but the details will be described later.

[0056] Next, with reference to Figure 3, the structure of the battery module 20 within the battery pack 2 will be described. Figure 3 is a schematic diagram showing the battery pack 2 of the battery system 1 according to this embodiment. As shown in Figure 3, the battery module 20 of this embodiment comprises a battery cell 21, an elastic member 22, an end plate 23, and a center plate 24. The battery module 20 may also include a bind bar, a gap filler, and a water jacket, which are not shown. However, the center plate 24 is not an essential component, and the battery module may be omitted.

[0057] The battery cell 21 is a secondary battery in which, for example, a solid material is used in at least a portion of the electrolyte. The battery cell 21 may be an all-solid-state battery using only a solid electrolyte, or it may be a semi-solid-state battery. The battery cell 21 may be a gel polymer type semi-solid-state battery in which an electrolyte is contained in a polymer gel, or it may be a clay type semi-solid-state battery in which a clay-like material in which an electrolyte is kneaded into the electrode material of the positive / negative electrode is used. Alternatively, the battery cell 21 may be a liquid-added type semi-solid-state battery in which a small amount of a fluid liquid material or a flexible gel polymer is added to the solid electrolyte. The negative electrode of the battery cell 21 in this embodiment may be Li metal, or a Li alloy containing Li. Furthermore, the negative electrode of the battery cell 21 in this embodiment may be Si, or a Si alloy containing Si, and if the battery cell 21 is an all-solid-state battery, the negative electrode may be made of a material other than these.

[0058] The battery pack 2 of this embodiment is constructed by stacking a plurality of rectangular or laminated battery cells 21 in a first direction. Each battery cell 21 has a predetermined thickness in the first direction, and the surface perpendicular to the first direction is substantially planar.

[0059] The elastic members 22 are positioned between each of the battery cells 21 stacked in the first direction. The elastic members 22 are restraining members that constrain the battery cells 21 and fill the gaps between adjacent battery cells 21 in the first direction.

[0060] The end plates 23 are positioned on one side (left side of the paper) and the other side (right side of the paper) of the assembly of multiple stacked battery cells 21 in the first direction. The assembly of multiple stacked battery cells 21 is sandwiched between a pair of end plates 23 in the first direction. The end plate 23 on one side in the first direction has an elastic member 22 facing it on the other side of the first direction. The end plate 23 on the other side in the first direction has an elastic member 22 facing it on the one side of the first direction.

[0061] The center plate 24 is positioned in the center of the assembly of stacked battery cells 21 in the first direction. Elastic members 22 are positioned opposite each other on both sides of the center plate 24 in the first direction.

[0062] <Relationship between battery constraint technology and thermal conductance dependence> Next, the battery restraint technology and its dependence on thermal conductance will be explained with reference to Figures 3 and 4. Figure 3 shows an image of the shape change of the elastic member 22 during charging and discharging. Figure 4 is a graph showing the relationship between the charge amount of the battery cell 21 and the surface pressure applied to the battery cell 21 during discharging and charging in the battery pack 2 of the battery system 1 according to this embodiment. In the graph of Figure 4, the vertical axis represents the surface pressure of the battery cell 21, and the horizontal axis represents the charge amount of the battery cell 21.

[0063] As shown in Figure 3, in the battery pack 2, as the State of Charge (SOC), which indicates the remaining charge, increases during charging, the battery cells 21 expand and the elastic member 22 becomes compressed. Conversely, as the SOC decreases during discharge, the battery cells 21 contract and the elastic member 22 recovers from its compressed state.

[0064] As shown in Figure 4, during charging of the battery pack 2, the surface pressure on the battery cells 21 increases in an upward-convex curve as the remaining charge of the battery cells 21 increases. In contrast, during discharging of the battery pack 2, the surface pressure on the battery cells 21 decreases in a downward-convex curve as the remaining charge of the battery cells 21 decreases. Thus, the relationship between the remaining charge of the battery cells 21 and the surface pressure on the battery cells 21 exhibits hysteresis characteristics during both charging and discharging.

[0065] Next, with reference to Figures 5 and 6, the relationship between surface pressure, thermal conductivity, and thermal conductance will be explained. Figure 5 is a graph showing an example of the thermal conductivity of the elastic member 22. In the graph of Figure 5, the vertical axis represents thermal conductivity [W / mK], and the horizontal axis represents surface pressure [MPa]. Figure 6 is a graph showing an example of thermal conductance between the battery cell 21 and the elastic member 22. In the graph of Figure 6, the vertical axis represents thermal conductance [W / mK].2 The horizontal axis shows the pressure [MPa], and the horizontal axis shows the surface pressure [MPa].

[0066] As shown in Figures 5 and 6, due to the structure that restrains the battery cell 21, if the surface pressure [MPa] that affects the thickness of the elastic member 22 increases, the thickness of the elastic member 22 decreases, affecting the thermal conductivity [W / mK] of the elastic member 22 and the thermal conductance [W / mK] between the battery cell 21 and the elastic member 22. 2 It can be seen that K improves.

[0067] Next, we will explain the difference in battery temperature between low and high SOC. Figure 7 is a graph showing an example of a current profile in which the current value decreases gradually over time. In the graph of Figure 7, the vertical axis represents current [A] and the horizontal axis represents time [min]. As shown in Figure 7, the current value decreases gradually over time.

[0068] Figure 8 is a graph comparing the temperature distribution of the battery cell 21 at time t1 when current is applied, for both the low SOC and high SOC cases shown in Figure 7. Figure 9 is a graph comparing the temperature distribution of the battery cell 21 at time t2 when current is applied, for both the low SOC and high SOC cases shown in Figure 7. Both graphs in Figure 8 and Figure 9 show the temperature when multiple battery cells 21 in the battery pack 2 are at low SOC and at high SOC. Cells a, b, c to x, y, and z are stacked in this order along the first direction of the battery module 20 with elastic members 22 in between, and constitute each battery cell 21 in the battery module 20. In the battery module 20, cells a to z are arranged symmetrically with respect to the center plate 24. That is, cell z is located on both sides of the center plate 24, with elastic members 22 in between.

[0069] As shown in Figures 8 and 9, in both cases at time t1 and time t2, the state of the battery pack 2 shows lower maximum and minimum temperatures when the SOC is high. In the battery module 20, at low SOC, the thermal conductance between the battery cell 21 and the elastic member 22 decreases, resulting in a higher temperature for the battery cell 21. On the other hand, in the battery module 20, at high SOC, the thermal conductance between the battery cell 21 and the elastic member 22 increases, resulting in a lower temperature for the battery cell 21.

[0070] As explained above, the State of Charge (SOC) of the battery pack 2 affects the temperature of the battery cells 21. Therefore, in this embodiment, the temperature is adjusted in accordance with the State of Charge (SOC) of the battery pack 2.

[0071] [First control mode] <Setting the heating stop temperature and cooling start temperature> First, the first control mode of the temperature control unit 37, which changes the heating stop temperature and cooling start temperature according to the state of charge (SOC) of the battery pack 2, will be described. The first control mode is a thermal management control that increases the heating stop temperature and cooling start temperature as the SOC transitions from low to high, in accordance with the characteristic that the thermal conductance between the battery cell 21 and the elastic member 22 changes according to the state of charge of the battery.

[0072] Specifically, in the first control mode, the temperature control unit 37 sets the heating stop temperature higher than the heating stop reference temperature, which is the reference temperature for stopping heating, because when the SOC is above a predetermined SOC, the thermal conductance between the battery cell 21 and the elastic member 22 tends to increase and the temperature of the battery cell 21 tends to decrease. It also sets the cooling start temperature higher than the cooling start reference temperature, which is the reference temperature for starting cooling.

[0073] Further, in the first control mode, when the SOC is equal to or lower than a predetermined SOC different from the above predetermined SOC, the temperature control unit 37 sets the heating stop temperature lower than the above heating stop reference temperature and sets the cooling start temperature lower than the above cooling start reference temperature, because the thermal conductance between the battery cell 21 and the elastic member 22 decreases and the temperature of the battery cell 21 tends to increase.

[0074] As described above, the heating stop temperature and the cooling start temperature are set according to the SOC state. The heating stop temperature and the cooling start temperature set according to the SOC state will be described with reference to FIG. 10. FIG. 10 is a diagram showing the heating stop temperature and the cooling start temperature set according to the SOC state.

[0075] Preferably, the SOC state is divided into a plurality of regions. The number of divided regions is not particularly limited. In the example of FIG. 10, the SOC state is divided into three regions: a low SOC state, a normal state, and a high SOC state. For example, when the SOC is equal to or less than the first threshold value SOC1 (SOC≦SOC1), the SOC state is determined to be the low SOC state. When the SOC is equal to or greater than the second threshold value SOC2 which is larger than the first threshold value SOC1 (SOC≧SOC2), the SOC state is determined to be the high SOC state. When the SOC is larger than the first threshold value SOC1 and smaller than the second threshold value SOC2 (SOC1<SOC<SOC2), the SOC state is determined to be the normal state. The first threshold value SOC1 and the second threshold value SOC2 are set to arbitrary values according to the battery characteristics.

[0076] As shown in FIG. 10, when the SOC state is the normal state, the heating stop reference temperature Ths and the cooling start reference temperature Tcs, which are reference temperatures preset according to the vehicle state, are set as they are, and neither is changed. Specifically, based on the vehicle state acquired by the vehicle state acquisition unit 36, the heating stop reference temperature Ths is set as the heating stop temperature, and the cooling start reference temperature Tcs is set as the cooling start temperature.

[0077] In contrast, in the case of a low SOC state, the heating stop temperature is set to Th1 and the cooling start temperature is set to Tc1. In the low SOC state, the thermal conductance between the battery cell 21 and the elastic member 22 decreases, causing the temperature of the battery cell 21 to rise. Therefore, the heating stop temperature Th1 is set to a temperature lower than the reference temperature, which is the heating stop reference temperature Ths. Similarly, the cooling start temperature Tc1 is set to a temperature lower than the reference temperature, which is the cooling start reference temperature Tcs.

[0078] Furthermore, in the case of a high SOC state, the heating stop temperature is set to Th2 and the cooling start temperature is set to Tc2. In the high SOC state, the thermal conductance between the battery cell 21 and the elastic member 22 increases, causing the temperature of the battery cell 21 to decrease. Therefore, the heating stop temperature Th2 is set to a higher temperature than the reference temperature, which is the heating stop reference temperature Ths. Similarly, the cooling start temperature Tc2 is set to a higher temperature than the reference temperature, which is the cooling start reference temperature Tcs.

[0079] Figure 11 shows the relationship between the State of Charge (SOC) and the heating stop temperature and cooling start temperature. As is clear from Figure 11, the heating stop temperature and cooling start temperature are set to increase as the SOC state increases. This is not limited to when the vehicle is in motion, but is the same for other vehicle states. For example, the same control is performed when the vehicle is idle (after driving), charging (normal charging), charging (rapid charging), idle (after charging), or for heating. That is, in the case of a low SOC state, the heating stop temperature and cooling start temperature are set to be lower by a predetermined temperature than the reference temperature in the normal state. Conversely, in the case of a high SOC state, the heating stop temperature and cooling start temperature are set to be higher by a predetermined temperature than the reference temperature in the normal state. The magnitude of the predetermined temperature is set according to the battery characteristics, and the magnitude of the predetermined temperature may differ between the heating stop temperature and the cooling start temperature, and may also differ between the low SOC state and the high SOC state.

[0080] <Processing flow of the first control mode> Next, referring to Figure 12, the flow of the process for setting the heating temperature range and cooling temperature range will be explained. Figure 12 is a flowchart showing an example of the flow of the process for setting the heating temperature range and cooling temperature range based on the SOC state.

[0081] In step S11, the vehicle status acquisition unit 36 ​​acquires a vehicle status signal from the vehicle control device 50.

[0082] In step S12, the temperature control unit 37 acquires a preset reference temperature (reference temperature) according to the vehicle state. Specifically, the temperature control unit 37 acquires the heating stop reference temperature Ths and the cooling start reference temperature Tcs as reference temperatures.

[0083] In step S13, the charge level acquisition unit 33 acquires the State of Charge (SOC) state, which indicates the charge status of the battery pack 2 (battery cell 21).

[0084] In step S14, the temperature control unit 37 determines whether the acquired SOC value is less than or equal to the first threshold SOC1. If the SOC value is less than or equal to the first threshold SOC1, i.e., if the system is in a low SOC state, the process proceeds to step S15 (step S14; YES). If the SOC value is not less than or equal to the first threshold SOC1, the process proceeds to step S16 (step S14; NO).

[0085] In step S15, the temperature control unit 37 sets the heating stop temperature Th to Th1, which is lower than the heating stop reference temperature Ths, and sets the cooling start temperature Tc to Tc1, which is lower than the cooling start reference temperature Tcs.

[0086] In step S16, the temperature control unit 37 determines whether the acquired SOC value is less than the second threshold SOC2. If the SOC value is less than the second threshold SOC2, i.e., the SOC state is in the normal state, the process proceeds to step S17 (step S16; YES). If the SOC value is not less than the second threshold SOC2, i.e., the SOC value is greater than or equal to the second threshold SOC2 and the SOC state is high, the process proceeds to step S18 (step S16; NO).

[0087] In step S17, the temperature control unit 37 sets the heating stop temperature Th to the heating stop reference temperature Ths, and sets the cooling start temperature Tc to the cooling start reference temperature Tcs.

[0088] In step S18, the temperature control unit 37 sets the heating stop temperature Th to Th2, which is higher than the heating stop reference temperature Ths, and sets the cooling start temperature Tc to Tc2, which is higher than the cooling start reference temperature Tcs.

[0089] The execution of steps S15, S17, or S18 reflects the SOC state in the temperature control of the battery cell 21. This completes the process.

[0090] Here, Figure 13 is a flowchart showing another example of the process for setting the heating temperature range and cooling temperature range based on the SOC state. In this other example, each process from step S21 to step S23 is the same as steps S11 to step S13 in the example above, while the processes from steps S24 to S28 differ from the processes from steps S14 to S18 in the example above.

[0091] Since the processes in steps S21 to S23 are the same as those in steps S11 to S13 in the example above, their explanation will be omitted.

[0092] In step S24, the temperature control unit 37 determines whether the acquired SOC value is less than the second threshold SOC2. If the SOC value is not less than the second threshold SOC2, i.e., the SOC value is greater than or equal to the second threshold SOC2 and the system is in a high SOC state, the process proceeds to step S25 (step S24; NO). If the SOC value is less than the second threshold SOC2, the process proceeds to step S26 (step S24; YES).

[0093] In step S25, the temperature control unit 37 sets the heating stop temperature Th to Th2, which is higher than the heating stop reference temperature Ths, and sets the cooling start temperature Tc to Tc2, which is higher than the cooling start reference temperature Tcs.

[0094] In step S26, the temperature control unit 37 determines whether the acquired SOC value is less than or equal to the first threshold SOC1. If the SOC value is not less than or equal to the first threshold SOC1, i.e., the SOC state is in the normal state, the process proceeds to step S27 (step S26; NO). If the SOC value is less than or equal to the first threshold SOC1, i.e., the SOC state is low, the process proceeds to step S28 (step S26; YES).

[0095] In step S27, the temperature control unit 37 sets the heating stop temperature Th to the heating stop reference temperature Ths, and sets the cooling start temperature Tc to the cooling start reference temperature Tcs.

[0096] In step S28, the temperature control unit 37 sets the heating stop temperature Th to Th1, which is lower than the heating stop reference temperature Ths, and sets the cooling start temperature Tc to Tc1, which is lower than the cooling start reference temperature Tcs.

[0097] The execution of steps S25, S27, or S28 reflects the SOC state in the temperature control of the battery cell 21. This completes the process.

[0098] As described above, in the example shown in Figure 12, it is first determined whether or not the system is in a low SOC state. If it is in a low SOC state, the heating stop temperature Th is set to Th1, which is lower than the heating stop reference temperature Ths, and the cooling start temperature Tc is set to Tc1, which is lower than the cooling start reference temperature Tcs, and the process is terminated. In contrast, in the other example shown in Figure 13, it is first determined whether or not the system is in a high SOC state. If it is in a high SOC state, the heating stop temperature Th is set to Th2, which is higher than the heating stop reference temperature Ths, and the cooling start temperature Tc is set to Tc2, which is higher than the cooling start reference temperature Tcs, and the process is terminated. In both of these examples, the SOC state, which affects the heat transfer characteristics, can be reflected in the temperature control of the battery cell 21, and the overall system can be made more efficient.

[0099] As mentioned above, in the first control mode, the heating stop temperature and cooling start temperature are set and changed according to the state of the occupant (SOC). However, in addition to the state of the SOC, the heating stop temperature and cooling start temperature may also be set and changed based on the contact pressure between the battery cell 21 and the elastic member 22, which is obtained by the contact pressure acquisition unit 35. Specifically, the greater the contact pressure, the greater the thermal conductance between the battery cell 21 and the elastic member 22, resulting in a lower temperature for the battery cell 21, so the heating stop temperature and cooling start temperature should be increased. Conversely, the smaller the contact pressure, the smaller the thermal conductance between the battery cell 21 and the elastic member 22, resulting in a higher temperature for the battery cell 21, so the heating stop temperature and cooling start temperature should be decreased. By setting and changing the heating stop temperature and cooling start temperature based on the contact pressure, which can be directly acquired by a pressure sensor or the like, more accurate temperature control can be achieved, and the entire system can be made more efficient.

[0100] [Second control mode] <Settings for heating and cooling capacity> Next, a second control mode of the temperature control unit 37 will be described, in which the heating capacity and cooling capacity are changed according to the state of charge (SOC) of the battery pack 2. The second control mode is a thermal management control that increases the heating capacity of the temperature control device and decreases the cooling capacity of the temperature control device as the SOC state transitions from a low SOC state to a high SOC state, in accordance with the characteristic that the thermal conductance between the battery cell 21 and the elastic member 22 changes according to the state of charge of the battery.

[0101] Specifically, in the second control mode, the temperature control unit 37, when the SOC is above a predetermined SOC, sets the heating capacity of the temperature control device higher than the heating reference capacity, which is the standard heating capacity, and sets the cooling capacity of the temperature control device lower than the cooling reference capacity, which is the standard cooling capacity, because the thermal conductance between the battery cell 21 and the elastic member 22 tends to increase and the temperature of the battery cell 21 tends to decrease.

[0102] Furthermore, in the second control mode, if the SOC is below a predetermined SOC different from the predetermined SOC mentioned above, the temperature control unit 37 sets the heating capacity of the temperature control device lower than the heating reference capacity and the cooling capacity of the temperature control device higher than the cooling reference capacity, because the thermal conductance between the battery cell 21 and the elastic member 22 tends to decrease and the temperature of the battery cell 21 tends to rise.

[0103] In this embodiment, the heating standard capacity and cooling standard capacity are set based on the vehicle state acquired by the vehicle state acquisition unit 36, and the heating capacity and cooling capacity are set based on the SOC state. The heating capacity and cooling capacity are set for each of the vehicle states, such as driving, standing (after driving), charging (normal charging), charging (rapid charging), standing (after charging), or keeping warm, as exemplified in the first control mode. Note that the heating standard capacity and cooling standard capacity may be set to the same capacity across vehicle states.

[0104] The SOC state to be determined in the second control mode is preferably divided into a plurality of regions, similarly to the first control mode. Even in the second control mode, the number of divided regions is not particularly limited. Similar to the first control mode, the SOC state is divided into three regions: a low SOC state, a normal state, and a high SOC state. For example, when the SOC is equal to or less than a first threshold SOC1 (SOC≦SOC1), the SOC state is determined to be the low SOC state. When the SOC is equal to or greater than a second threshold SOC2 that is larger than the first threshold SOC1 (SOC≧SOC2), the SOC state is determined to be the high SOC state. When the SOC is larger than the first threshold SOC1 and smaller than the second threshold SOC2 (SOC1<SOC<SOC2), the SOC state is determined to be the normal state. The first threshold SOC1 and the second threshold SOC2 are set to arbitrary values according to battery characteristics.

[0105] When the SOC state is the normal state, the heating capacity and the cooling capacity are not changed from the reference heating capacity and the reference cooling capacity. In the case of the low SOC state, since the thermal conductance between the battery cell 21 and the elastic member 22 decreases and the temperature of the battery cell 21 rises, the cooling capacity is changed to an enhanced cooling capacity with a higher cooling power than the reference cooling capacity, and the heating capacity is changed to a reduced heating capacity with a lower heating power than the reference heating capacity. On the other hand, in the case of the high SOC state, since the thermal conductance between the battery cell 21 and the elastic member 22 increases and the temperature of the battery cell 21 decreases, the cooling capacity is changed to a reduced cooling capacity with a lower cooling power than the reference cooling capacity, and the heating capacity is changed to an enhanced heating capacity with a higher heating power than the reference heating capacity.

[0106] In this way, as the SOC state becomes higher, the cooling capacity is set lower, and the heating capacity is set higher.

[0107] The method for changing the cooling capacity is not particularly limited, and various methods can be employed. For example, the cooling capacity can be enhanced by increasing the flow rate of the heat transfer medium by increasing the power consumption of the liquid transfer device 11, which is an electric water pump during cooling control. Also, when a heat dissipation device 16 such as a chiller using a compressor is used in the chilled water circuit 10, the cooling capacity can be enhanced by improving the cooling capacity of the heat dissipation device 16, for example, by increasing the rotational speed of the compressor.

[0108] On the other hand, a reduction in cooling capacity can be achieved by lowering the flow rate of the heat transfer medium by reducing the power consumption of the liquid transfer device 11 during cooling control. Also, when using a heat exhaust device 16 such as a chiller, a reduction in cooling capacity can be achieved by reducing the cooling capacity of the heat exhaust device 16 by reducing the rotation speed of the compressor. Furthermore, when using a radiator or the like as the heat exhaust device 16, a reduction in cooling capacity can also be achieved by closing the air volume control device 13 such as an AGS, thereby reducing the cooling capacity of the heat exhaust device 16 such as a radiator.

[0109] The method for changing the heating capacity is not particularly limited, and various methods can be employed. For example, a reduction in heating capacity can be achieved by lowering the flow rate of the heat transfer medium by reducing the power consumption of the liquid transfer device 11 during heating control. Alternatively, a reduction in heating capacity can also be achieved by lowering the output of the heating device 12 to reduce the amount of heat applied to the heat transfer medium.

[0110] On the other hand, enhancing the heating capacity can be achieved by increasing the flow rate of the heat transfer medium by increasing the power consumption of the liquid transfer device 11 during heating control. Alternatively, enhancing the heating capacity can also be achieved by increasing the output of the heating device 12 to increase the amount of heat applied to the heat transfer medium.

[0111] Figure 14 is a graph comparing the temperature distribution of the battery cell 21 at time t1 when the cooling standard capacity is set and when the enhanced cooling capacity is set, as shown in Figure 7. Figure 15 is a graph comparing the temperature distribution of the battery cell 21 at time t2 when the cooling standard capacity is set and when the enhanced cooling capacity is set, as shown in Figure 7.

[0112] Figures 14 and 15 show the temperature distribution of the battery cell 21 when cooled with the standard cooling capacity in a high SOC state, and the temperature distribution of the battery cell 21 when cooled with the enhanced cooling capacity in a high SOC state. Cells a, b, c to x, y, and z are stacked in this order along the first direction of the battery module 20, with elastic members 22 in between, and constitute each battery cell 21 in the battery module 20. In the battery module 20, cells a to z are arranged symmetrically with respect to the center plate 24. That is, cell z is located on both sides of the center plate 24, with elastic members 22 in between. The graphs in Figures 14 and 15 show that the temperature of the entire battery module 20 can be reduced by enhancing the cooling capacity in both cases at time t1 and time t2. It can be seen that the temperature reduction when cooled with the enhanced cooling capacity is greater than when cooled with the standard cooling capacity at time t2, as shown in Figure 15, compared to time t1, as shown in Figure 14. From the graphs in Figures 14 and 15, it can be said that by strengthening the cooling capacity by replacing the control that speeds up the cooling start temperature, as in the first control mode, it is possible to cope with the characteristic of the expanding and contracting battery cell 21 where the thermal conductance changes.

[0113] <Processing flow for the second control mode> Next, with reference to Figure 16, the flow of the process for setting heating capacity and cooling capacity will be explained. Figure 16 is a flowchart showing an example of the flow of the process for setting heating capacity and cooling capacity based on the State of Charge (SOC) state.

[0114] In step S31, the vehicle status acquisition unit 36 ​​acquires a vehicle status signal from the vehicle control device 50.

[0115] In step S32, the temperature control unit 37 acquires a preset reference setting (reference capacity) according to the vehicle state. In the second control mode, the temperature control unit 37 acquires the cooling reference capacity and the heating reference capacity as reference settings.

[0116] In step S33, the charge level acquisition unit 33 acquires the State of Charge (SOC), which indicates the charge status of the battery pack 2 (battery cell 21).

[0117] In step S34, the temperature control unit 37 determines whether the acquired SOC value is less than or equal to the first threshold SOC1. If the SOC value is less than or equal to the first threshold SOC1, i.e., if the system is in a low SOC state, the process proceeds to step S35 (step S34; YES). If the SOC value is not less than or equal to the first threshold SOC1, the process proceeds to step S36 (step S34; NO).

[0118] In step S35, the temperature control unit 37 enhances the cooling capacity of the temperature control device and reduces its heating capacity. This results in a state where, when a cooling request is made, cooling control based on the enhanced cooling capacity is executed. Similarly, when a heating request is made, heating control based on the reduced heating capacity is executed.

[0119] In step S36, the temperature control unit 37 determines whether the acquired SOC value is less than the second threshold SOC2. If the SOC value is less than the second threshold SOC2, i.e., the SOC state is in the normal state, the process proceeds to step S37 (step S36; YES). If the SOC value is not less than the second threshold SOC2, i.e., the SOC value is greater than or equal to the second threshold SOC2 and the SOC state is high, the process proceeds to step S38 (step S36; NO).

[0120] In step S37, the temperature control unit 37 sets the normal cooling reference capacity and heating reference capacity as they are. This ensures that when a cooling request is made, cooling control based on the cooling reference capacity is executed. Similarly, when a heating request is made, heating control based on the heating reference capacity is executed.

[0121] In step S38, the temperature control unit 37 reduces the cooling capacity and enhances the heating capacity. As a result, when a cooling request is made, cooling control based on the reduced cooling capacity is executed. Similarly, when a heating request is made, heating control based on the enhanced heating capacity is executed.

[0122] The execution of steps S35, S37, or S38 reflects the SOC state in the temperature control of the battery cell 21. This completes the process.

[0123] Here, Figure 17 is a flowchart showing another example of the process for setting heating capacity and cooling capacity based on the SOC state. In this other example, each process from step S41 to step S43 is the same as steps S31 to step S33 in the example above, while the processes from steps S44 to S48 differ from the processes from steps S34 to S38 in the example above.

[0124] Since the processes in steps S41 to S43 are the same as those in steps S31 to S33 in the example above, their explanation will be omitted.

[0125] In step S44, the temperature control unit 37 determines whether the acquired SOC value is less than the second threshold SOC2. If the SOC value is not less than the second threshold SOC2, i.e., the SOC value is greater than or equal to the second threshold SOC2 and the system is in a high SOC state, the process proceeds to step S45 (step S44; NO). If the SOC value is less than the second threshold SOC2, the process proceeds to step S46 (step S44; YES).

[0126] In step S45, the temperature control unit 37 reduces the cooling capacity of the temperature control device and increases its heating capacity. As a result, when a cooling request is made, cooling control based on the reduced cooling capacity is executed. Similarly, when a heating request is made, heating control based on the enhanced heating capacity is executed.

[0127] In step S46, the temperature control unit 37 determines whether the acquired SOC value is less than or equal to the first threshold SOC1. If the SOC value is not less than or equal to the first threshold SOC1, i.e., the SOC state is in the normal state, the process proceeds to step S47 (step S46; NO). If the SOC value is less than or equal to the first threshold SOC1, i.e., the SOC state is low, the process proceeds to step S48 (step S46; YES).

[0128] In step S47, the temperature control unit 37 sets the normal cooling reference capacity and heating reference capacity as they are. This ensures that when a cooling request is made, cooling control based on the cooling reference capacity is executed. Similarly, when a heating request is made, heating control based on the heating reference capacity is executed.

[0129] In step S48, the temperature control unit 37 enhances the cooling capacity and reduces the heating capacity. As a result, when a cooling request is made, cooling control based on the enhanced cooling capacity is executed. Similarly, when a heating request is made, heating control based on the reduced heating capacity is executed.

[0130] The execution of steps S45, S47, or S48 reflects the SOC state in the temperature control of the battery cell 21. This completes the process.

[0131] As described above, in the example shown in Figure 16, it is first determined whether or not the system is in a low SOC state. If it is, the cooling capacity of the temperature control device is set to enhanced cooling capacity, and the heating capacity of the temperature control device is set to reduced heating capacity, and the process is terminated. In contrast, in the other example shown in Figure 17, it is first determined whether or not the system is in a high SOC state. If it is in a high SOC state, the cooling capacity of the temperature control device is set to reduced cooling capacity, and the heating capacity of the temperature control device is set to enhanced heating capacity, and the process is terminated. In both of these examples, the SOC state, which affects the heat transfer characteristics, can be reflected in the temperature control of the battery cell 21, and the overall system can be made more efficient.

[0132] As mentioned above, in the second control mode, the heating and cooling capacities of the temperature control device are set and changed according to the state of charge (SOC). However, in addition to the state of charge, the heating and cooling capacities of the temperature control device may also be set and changed based on the contact pressure between the battery cell 21 and the elastic member 22, which is acquired by the contact pressure acquisition unit 35. Specifically, the greater the contact pressure, the greater the thermal conductance between the battery cell 21 and the elastic member 22, resulting in a lower temperature for the battery cell 21. Therefore, the heating capacity of the temperature control device is increased and the cooling capacity is decreased. Conversely, the smaller the contact pressure, the smaller the thermal conductance between the battery cell 21 and the elastic member 22, resulting in a higher temperature for the battery cell 21. Therefore, the heating capacity of the temperature control device is decreased and the cooling capacity is increased. By changing the heating and cooling capacities of the temperature control device based on the contact pressure, which can be directly acquired by a pressure sensor or the like, more accurate temperature control can be achieved, and the overall system can be made more efficient.

[0133] The effects of this embodiment described above can be summarized as follows:

[0134] The battery system 1 in the first control mode of this embodiment includes a battery cell 21 that expands and contracts according to the remaining charge, and an elastic member 22 adjacent to the battery cell 21 whose contact pressure with the battery cell 21 changes in accordance with the expansion and contraction of the battery cell 21. It also includes a temperature control unit 37 that performs heating or cooling of the battery cell 21 based on a preset reference temperature, and a charge level acquisition unit 33 that acquires the status of the remaining charge of the battery cell 21. The temperature control unit 37 sets the heating stop temperature higher than the heating stop reference temperature Ths and the cooling start temperature higher than the cooling start reference temperature Tcs when the remaining charge is above a predetermined level. Alternatively, the temperature control unit 37 sets the heating stop temperature lower than the heating stop reference temperature Ths and the cooling start temperature lower than the cooling start reference temperature Tcs when the remaining charge is below a predetermined level.

[0135] Since the interfacial thermal conductance depends on the battery's charge state, if thermal management control is implemented uniformly regardless of the charge state, heating / cooling may be insufficient or excessive, leading to reduced control efficiency. Because the interfacial thermal conductance between the battery cell 21 and the elastic member 22 changes according to the surface pressure, the cell temperature tends to be higher in the low-SOC state when comparing the low-SOC state and the high-SOC state. Thus, since the temperature trend of the battery cell 21 differs depending on the battery's charge state, it is necessary to construct a control system based on this characteristic. In this regard, the battery system 1 of this embodiment performs thermal management control that, in the low-SOC state, the thermal conductance between the battery cell 21 and the elastic member 22 decreases, causing the temperature of the battery cell 21 to rise. Therefore, the heating stop temperature and cooling start temperature are relatively lowered to accelerate the stopping of heating and the start of cooling. Alternatively, in a high SOC state, the thermal conductance between the battery cell 21 and the elastic member 22 increases, causing the temperature of the battery cell 21 to decrease. Therefore, thermal management control is performed by relatively increasing the heating stop temperature and cooling start temperature to delay the heating stop and cooling start. This allows the change in thermal conductance caused by the change in contact pressure between the battery cell 21 and the elastic member 22 to be accurately reflected in the temperature control of the battery cell 21, thereby improving the efficiency of the entire system.

[0136] Furthermore, the battery system 1 in the second control mode of this embodiment includes a battery cell 21 that expands and contracts according to the remaining charge, and an elastic member 22 adjacent to the battery cell 21 whose contact pressure with the battery cell 21 changes in accordance with the expansion and contraction of the battery cell 21. It also includes a temperature control device including a liquid supply device 11, a heating device 12, an air volume adjustment device 13, and a heat dissipation device 16. A temperature control unit 37 performs heating or cooling of the battery cell 21 based on a preset reference capacity of the temperature control device, and a charge level acquisition unit 33 acquires the status of the remaining charge of the battery cell 21. The temperature control unit 37 sets the heating capacity of the temperature control device higher than the heating reference capacity and the cooling capacity of the temperature control device lower than the cooling reference capacity when the remaining charge is above a predetermined level. Alternatively, the temperature control unit 37 sets the heating capacity of the temperature control device lower than the heating reference capacity and the cooling capacity of the temperature control device higher than the cooling reference capacity when the remaining charge is below a predetermined level.

[0137] In other words, in the battery system 1 of this embodiment, when the low SOC state, the thermal conductance between the battery cell 21 and the elastic member 22 decreases, causing the temperature of the battery cell 21 to rise. Therefore, thermal management control is performed to enhance the cooling capacity and reduce the heating capacity. Alternatively, when the high SOC state, the thermal conductance between the battery cell 21 and the elastic member 22 increases, causing the temperature of the battery cell 21 to fall. Therefore, thermal management control is performed to reduce the cooling capacity and enhance the heating capacity. This makes it possible to accurately reflect the change in thermal conductance caused by the change in contact pressure between the battery cell 21 and the elastic member 22 in the temperature control of the battery cell 21, thereby improving the efficiency of the entire system.

[0138] Furthermore, the temperature control unit 37 of this embodiment may determine which of a plurality of pre-set regions the remaining charge acquired by the remaining charge acquisition unit 33 belongs to, and set the heating stop temperature and cooling start temperature based on this determination result. This makes it possible to reliably reflect the change in thermal conductance caused by the change in contact pressure between the battery cell 21 and the elastic member 22 through temperature control of the battery cell 21, thereby making the entire system more reliable and efficient.

[0139] Furthermore, the temperature control unit 37 of this embodiment may determine which of a plurality of pre-set regions the remaining charge acquired by the remaining charge acquisition unit 33 belongs to, and set the heating capacity and cooling capacity of the temperature control device based on this determination result. This makes it possible to reliably reflect the change in thermal conductance caused by the change in contact pressure between the battery cell 21 and the elastic member 22 through temperature control of the battery cell 21, thereby making the entire system more reliable and efficient.

[0140] Furthermore, the battery system 1 of this embodiment may further include a contact pressure acquisition unit 35 that acquires the contact pressure between the battery cell 21 and the elastic member 22, and the temperature control unit 37 may set the heating stop temperature and the cooling start temperature based on the remaining charge and the contact pressure. By changing the heating stop temperature and the cooling start temperature based on the contact pressure, which can be directly acquired by a pressure sensor or the like, in addition to the remaining charge, temperature control can be made more accurate and the entire system can be made more efficient.

[0141] Furthermore, the battery system 1 of this embodiment may further include a contact pressure acquisition unit 35 that acquires the contact pressure between the battery cell 21 and the elastic member 22, and the temperature control unit 37 may set the heating capacity and cooling capacity of the temperature control device based on the remaining charge and the contact pressure. By changing the heating capacity and cooling capacity of the temperature control device based on the contact pressure, which can be directly acquired by a pressure sensor or the like, in addition to the remaining charge, temperature control can be made more accurate and the entire system can be made more efficient.

[0142] Furthermore, the battery system 1 of this embodiment may further include a vehicle state acquisition unit 36 ​​for acquiring vehicle status, and the temperature control unit 37 may set the heating stop temperature and cooling start temperature based on the remaining charge and vehicle status. This enables temperature control that takes into account the vehicle status along with changes in thermal conductance, making the entire system more efficient.

[0143] Furthermore, the battery system 1 of this embodiment may further include a vehicle state acquisition unit 36 ​​for acquiring vehicle status, and the temperature control unit 37 may set the heating capacity and cooling capacity of the temperature control device based on the remaining charge and vehicle status. Among the vehicle states of driving, leaving the vehicle idle after driving, normal charging, rapid charging, leaving the vehicle idle after charging, or keeping the vehicle warm, the remaining charge tends to fluctuate particularly when driving, normal charging, and rapid charging. According to this embodiment, even when driving, normal charging, and rapid charging are in progress, the heating capacity and cooling capacity of the temperature control device are set and changed based on the remaining charge and vehicle status, so that changes in thermal conductance can be reflected more accurately in the temperature control of the battery cells 21, and the entire system can be made more efficient.

[0144] Furthermore, the battery system 1 of this embodiment may include a fluid delivery device 11 as a temperature control device that controls the flow rate of the heat transfer medium supplied to the battery cells 21, and the temperature control unit 37 may change the flow rate of the heat transfer medium by the fluid delivery device 11 based on the remaining charge. Alternatively, the battery system 1 of this embodiment may include a heat dissipation device 16 as a temperature control device that cools the heat transfer medium supplied to the battery cells 21, and the temperature control unit 37 may change the cooling setting of the heat dissipation device 16 based on the remaining charge. Alternatively, the battery system 1 of this embodiment may include a heating device 12 as a temperature control device that heats the heat transfer medium supplied to the battery cells 21, and the temperature control unit 37 may change the heating setting of the heating device 12 based on the remaining charge. Alternatively, the battery system 1 of this embodiment may include, as a temperature control device, a heat dissipation device 16 arranged in the circuit through which the heat transfer medium supplied to the battery cells 21 flows, and an air volume adjustment device 13 capable of adjusting the amount of air supplied to the heat dissipation device 16, and the temperature control unit 37 may control the air volume adjustment device 13 based on the remaining charge. In either of these cases, it becomes possible to more reliably achieve temperature control in response to changes in thermal conductance, and the entire system can be made more reliable and efficient.

[0145] Furthermore, in the battery system 1 of this embodiment, the battery cell 21 may be an all-solid-state battery. All-solid-state batteries, which have a greater volume difference due to expansion and contraction compared to semi-solid-state batteries, also exhibit larger changes in thermal conductance. In this respect, according to this embodiment, since temperature control is performed taking into account the change in thermal conductance, more efficient temperature control can be achieved.

[0146] Furthermore, in the battery system 1 of this embodiment, the negative electrode of the battery cell 21 may be composed of Li metal or a Li alloy. This makes it possible to achieve temperature control that takes into account changes in thermal conductance in the battery cell 21 applied to a negative electrode containing Li metal or a Li alloy.

[0147] Furthermore, in the battery system 1 of this embodiment, the negative electrode of the battery cell 21 may be composed of Si or a Si alloy. This makes it possible to achieve temperature control that takes into account changes in thermal conductance in the battery cell 21 applied to a negative electrode containing Si or a Si alloy.

[0148] Although embodiments of the present invention have been described above, the invention is not limited to the embodiments described above. Furthermore, the effects described in the above embodiments are merely a list of preferred effects and are not limited to those described in the above embodiments.

[0149] For example, the present invention can also be applied to a battery system 1 having a chilled water circuit 10a as shown in Figure 18. Figure 18 is a diagram showing a chilled water circuit 10a of a modified battery system 1. The same reference numerals are used for components that are common or similar to those in the above embodiment. As shown in Figure 18, a liquid transfer device 11, a battery pack 2, a heating device 12, a tank 14, a charger 6, a drive unit 17, a heat dissipation device 16 such as a radiator, and a five-way valve 18 are arranged on the chilled water circuit 10a. The chilled water circuit 10a cools the battery pack 2, the drive unit 17, the charger 6, etc., by switching the path using the five-way valve 18. Even in this modified example, changes in heat transfer characteristics can be accurately reflected in the temperature control of the battery cells 21.

[0150] Furthermore, although the battery system 1 of the above embodiment was described as being configured to perform both a first control mode for changing the settings of the heating stop temperature and the cooling start temperature, and a second control mode for changing the settings of the heating capacity and the cooling capacity, it may also be configured to perform control of only one of the first control mode or the second control mode. Alternatively, it may be configured to change only the settings of either the heating stop temperature or the cooling start temperature, or to change only the settings of either the heating capacity or the cooling capacity.

[0151] Furthermore, although the battery system 1 of the above embodiment was described as having a surface pressure acquisition unit 35 and a vehicle state acquisition unit 36, it is also possible to have a configuration that does not include these functional units.

[0152] Furthermore, although the battery system 1 in the above embodiment was described as having a configuration that includes a liquid supply device 11, a heating device 12, an air volume adjustment device 13, and a heat dissipation device 16 as a temperature control device, it is sufficient if it can control the heating and cooling of the battery cell 21, and it is not necessary to have all of these.

[0153] Furthermore, according to the above embodiment, a control method for the battery system 1, which is executed by the battery system 1, and a program that causes a computer to execute the control method are also provided. The control method for the battery system 1 is executed by the CPU of the battery ECU 3, and the program is stored in the memory of the battery ECU 3. These control methods for the battery system 1 and the program that causes a computer to execute the control method provide the same effects as the battery system 1 described above. [Explanation of Symbols]

[0154] 1. Battery System 2 Battery Packs 3. Battery ECU 11. Fluid delivery device 12 Heating devices 13. Air volume adjustment device 16. Heat dissipation device 20 Battery Modules 21 battery cells 22 Elastic members 31 Battery temperature acquisition unit 32 Battery voltage acquisition unit 33. Battery level acquisition unit 35 Surface pressure acquisition section 36 Vehicle status acquisition unit 37 Temperature Control Unit

Claims

1. Battery cells that expand and contract according to the remaining charge, A battery system comprising an elastic member adjacent to the battery cell, the contact pressure with the battery cell changes in accordance with the expansion and contraction of the battery cell, A temperature control unit that performs heating or cooling of the battery cell based on a preset reference temperature, The system includes a charge level acquisition unit that acquires the charge level status of the battery cell, A battery system in which, when the remaining charge is above a predetermined level, the temperature control unit sets the heating stop temperature at which heating is stopped to a higher level than the heating stop reference temperature, which is the reference temperature for stopping heating, and sets the cooling start temperature at which cooling is started to a higher level than the cooling start reference temperature, which is the reference temperature for starting cooling.

2. Battery cells that expand and contract according to the remaining charge, A battery system comprising an elastic member adjacent to the battery cell, the contact pressure with the battery cell changes in accordance with the expansion and contraction of the battery cell, A temperature control unit that performs heating or cooling of the battery cell based on a preset reference temperature, The system includes a charge level acquisition unit that acquires the charge level status of the battery cell, A battery system in which, when the remaining charge is below a predetermined level, the temperature control unit sets the heating stop temperature at which heating is stopped to a lower level than the heating stop reference temperature, which is the reference temperature for stopping heating, and sets the cooling start temperature at which cooling is started to a lower level than the cooling start reference temperature, which is the reference temperature for starting cooling.

3. Battery cells that expand and contract according to the remaining charge, A battery system comprising an elastic member adjacent to the battery cell, the contact pressure with the battery cell changes in accordance with the expansion and contraction of the battery cell, Temperature control device, A temperature control unit that performs heating or cooling of the battery cell based on a preset reference capacity of the temperature control device, The system includes a charge level acquisition unit that acquires the charge level status of the battery cell, A battery system in which, when the remaining charge is above a predetermined level, the temperature control unit sets the heating capacity of the temperature control device to be higher than the heating reference capacity, which is the reference capacity for heating, and sets the cooling capacity of the temperature control device to be lower than the cooling reference capacity, which is the reference capacity for cooling.

4. Battery cells that expand and contract according to the remaining charge, A battery system comprising an elastic member adjacent to the battery cell, the contact pressure with the battery cell changes in accordance with the expansion and contraction of the battery cell, Temperature control device, A temperature control unit that performs heating or cooling of the battery cell based on a preset reference capacity of the temperature control device, The system includes a charge level acquisition unit that acquires the charge level status of the battery cell, A battery system in which, when the remaining charge is below a predetermined level, the temperature control unit sets the heating capacity of the temperature control device to be lower than the heating reference capacity, which is the reference capacity for heating, and sets the cooling capacity of the temperature control device to be higher than the cooling reference capacity, which is the reference capacity for cooling.

5. The battery system according to claim 1 or 2, wherein the temperature control unit determines which of a plurality of predetermined regions the remaining charge belongs to, and sets the heating stop temperature and the cooling start temperature based on the determination result.

6. The battery system further comprises a surface pressure acquisition unit that acquires the contact surface pressure between the battery cell and the elastic member, The battery system according to claim 1 or 2, wherein the temperature control unit sets the heating stop temperature and the cooling start temperature based on the contact pressure.

7. The battery system according to claim 3 or 4, wherein the temperature control unit determines which of a plurality of predetermined regions the remaining charge belongs to, and sets the heating capacity and the cooling capacity based on the determination result.

8. The battery system further comprises a surface pressure acquisition unit that acquires the contact surface pressure between the battery cell and the elastic member, The battery system according to claim 3 or 4, wherein the temperature control unit sets the heating capacity and the cooling capacity based on the contact pressure.

9. The aforementioned battery system further comprises a vehicle status acquisition unit that acquires the vehicle status, The battery system according to claim 1 or 2, wherein the temperature control unit sets the heating stop temperature and the cooling start temperature based on the vehicle state.

10. The aforementioned battery system further comprises a vehicle status acquisition unit that acquires the vehicle status, The battery system according to claim 3 or 4, wherein the temperature control unit sets the heating capacity and the cooling capacity based on the vehicle state.

11. The temperature control device includes a fluid supply device that controls the flow rate of the heat transfer medium supplied to the battery cell, The battery system according to claim 3 or 4, wherein the temperature control unit changes the flow rate of the heat transfer medium by the liquid transfer device based on the remaining charge.

12. The temperature control device includes a heat dissipation device for cooling the heat transfer medium supplied to the battery cell, The battery system according to claim 3 or 4, wherein the temperature control unit changes the cooling setting of the heat dissipation device based on the remaining charge.

13. The temperature control device includes a heating device that heats the heat transfer medium supplied to the battery cell. The battery system according to claim 3 or 4, wherein the temperature control unit changes the heating setting of the heating device based on the remaining charge.

14. The temperature control device includes a heat dissipation device arranged in a circuit through which a heat transfer medium supplied to the battery cell flows, and an air volume adjustment device capable of adjusting the amount of air supplied to the heat dissipation device. The battery system according to claim 3 or 4, wherein the temperature control unit controls the air volume adjustment device based on the remaining charge.

15. The battery system according to claims 1 to 4, wherein the battery cell is an all-solid-state battery cell.

16. The battery system according to claims 1 to 4, wherein the negative electrode of the battery cell comprises Li metal or Li alloy.

17. The battery system according to claims 1 to 4, wherein the negative electrode of the battery cell comprises Si or a Si alloy.

18. Battery cells that expand and contract according to the remaining charge, A control method for a battery system, comprising: an elastic member adjacent to the battery cell, the contact pressure with the battery cell changing in accordance with the expansion and contraction of the battery cell; A temperature control step in which the battery cell is heated or cooled based on a preset reference temperature, The system includes a charge level acquisition step for acquiring the charge level status of the battery cell, A battery system control method in which, in the temperature control step, if the remaining charge is above a predetermined level, the heating stop temperature at which heating is stopped is set higher than the heating stop reference temperature, which is the reference temperature for stopping heating, and the cooling start temperature at which cooling is started is set higher than the cooling start reference temperature, which is the reference temperature for starting cooling.

19. Battery cells that expand and contract according to the remaining charge, A control method for a battery system, comprising: an elastic member adjacent to the battery cell, the contact pressure with the battery cell changing in accordance with the expansion and contraction of the battery cell; A temperature control step in which the battery cell is heated or cooled based on a preset reference temperature, The system includes a charge level acquisition step for acquiring the charge level status of the battery cell, A battery system control method in which, in the temperature control step, if the remaining charge is below a predetermined level, the heating stop temperature at which heating is stopped is set lower than the heating stop reference temperature, which is the reference temperature for stopping heating, and the cooling start temperature at which cooling is started is set lower than the cooling start reference temperature, which is the reference temperature for starting cooling.

20. Battery cells that expand and contract according to the remaining charge, An elastic member adjacent to the battery cell, the contact pressure with the battery cell changes in accordance with the expansion and contraction of the battery cell, A control method for a battery system including a temperature control device, A temperature control step in which the battery cell is heated or cooled based on a preset reference capacity of the temperature control device, The system includes a charge level acquisition step for acquiring the charge level status of the battery cell, A battery system control method in which, in the temperature control step, if the remaining charge is above a predetermined level, the heating capacity of the temperature control device is set higher than the heating reference capacity, which is the reference capacity for heating, and the cooling capacity of the temperature control device is set lower than the cooling reference capacity, which is the reference capacity for cooling.

21. Battery cells that expand and contract according to the remaining charge, An elastic member adjacent to the battery cell, the contact pressure with the battery cell changes in accordance with the expansion and contraction of the battery cell, A control method for a battery system including a temperature control device, A temperature control step in which the battery cell is heated or cooled based on a preset reference capacity of the temperature control device, The system includes a charge level acquisition step for acquiring the charge level status of the battery cell, A battery system control method in which, in the temperature control step, when the remaining charge is below a predetermined level, the heating capacity of the temperature control device is set lower than the heating reference capacity, which is the reference capacity for heating, and the cooling capacity of the temperature control device is set higher than the cooling reference capacity, which is the reference capacity for cooling.

22. Battery cells that expand and contract according to the remaining charge, A program for causing a computer to execute a control method for a battery system, which includes an elastic member adjacent to the battery cell, the contact pressure with the battery cell changing in accordance with the expansion and contraction of the battery cell, A temperature control step in which the battery cell is heated or cooled based on a preset reference temperature, The system includes a charge level acquisition step for acquiring the charge level status of the battery cell, In the temperature control step, if the remaining charge is above a predetermined level, the program sets the heating stop temperature at which heating is stopped to a higher level than the heating stop reference temperature, which is the reference temperature for stopping heating, and sets the cooling start temperature at which cooling is started to a higher level than the cooling start reference temperature, which is the reference temperature for starting cooling.

23. Battery cells that expand and contract according to the remaining charge, A program for causing a computer to execute a control method for a battery system, which includes an elastic member adjacent to the battery cell, the contact pressure with the battery cell changing in accordance with the expansion and contraction of the battery cell, A temperature control step in which the battery cell is heated or cooled based on a preset reference temperature, The system includes a charge level acquisition step for acquiring the charge level status of the battery cell, In the temperature control step, if the remaining charge is below a predetermined level, the program sets the heating stop temperature at which heating is stopped to a lower level than the heating stop reference temperature, which is the reference temperature for stopping heating, and sets the cooling start temperature at which cooling is started to a lower level than the cooling start reference temperature, which is the reference temperature for starting cooling.

24. Battery cells that expand and contract according to the remaining charge, An elastic member adjacent to the battery cell, the contact pressure with the battery cell changes in accordance with the expansion and contraction of the battery cell, A program for causing a computer to execute a control method for a battery system including a temperature control device, A temperature control step in which the battery cell is heated or cooled based on a preset reference capacity of the temperature control device, The system includes a charge level acquisition step for acquiring the charge level status of the battery cell, In the temperature control step, if the remaining charge is above a predetermined level, the program sets the heating capacity of the temperature control device to be higher than the heating reference capacity, which is the reference capacity for heating, and sets the cooling capacity of the temperature control device to be lower than the cooling reference capacity, which is the reference capacity for cooling.

25. Battery cells that expand and contract according to the remaining charge, An elastic member adjacent to the battery cell, the contact pressure with the battery cell changes in accordance with the expansion and contraction of the battery cell, A program for causing a computer to execute a control method for a battery system including a temperature control device, A temperature control step in which the battery cell is heated or cooled based on a preset reference capacity of the temperature control device, The system includes a charge level acquisition step for acquiring the charge level status of the battery cell, In the temperature control step, if the remaining charge is below a predetermined level, the program sets the heating capacity of the temperature control device to be lower than the heating reference capacity, which is the reference capacity for heating, and sets the cooling capacity of the temperature control device to be higher than the cooling reference capacity, which is the reference capacity for cooling.

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