Battery temperature control system and battery temperature control method

Abstract

To properly control temperatures of a plurality of batteries.SOLUTION: A battery temperature control system 1 cools a first battery 6 with high internal resistance and a second battery 7 with low internal resistance. The battery temperature control system 1 includes: a radiator 8 supplying a refrigerant to the first battery 6 and the second battery 7; parallel refrigerant paths (paths 21, 22, 23, 25, 26, 27, 28) connecting the radiator 8 and each of the first battery 6 and the second battery 7 in parallel; series refrigerant paths (paths 21, 22, 24, 26, 27, 28) connecting from the radiator 8 to the second battery 7 via the first battery 6; and supply path selection mechanisms (a first valve 41, a second valve 42 and a third valve 43) selecting, between the parallel refrigerant path and the series refrigerant path, a refrigerant supply path from the radiator 8 to the first battery 6 and the second battery 7.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a battery temperature control system and a battery temperature control method for controlling the temperature of a battery. [Background technology]

[0002] Conventionally, vehicles equipped with multiple batteries have been proposed to improve the running performance of vehicles that use a drive motor as a running drive source. It is generally known that the charge / discharge characteristics of a battery deteriorate when its temperature decreases. Therefore, a technology has been proposed in which power is exchanged between two batteries to control the temperature rise of each battery (for example, see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2008-60047 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned conventional technology, due to differences in the characteristics (e.g., heat generation amount, heat transfer amount, heat capacity) of the two batteries, a temperature difference occurs between the batteries when the batteries are heated, and the charge / discharge characteristics of the battery with a lower temperature may be deteriorated. Therefore, it is important to appropriately control the temperature of each battery so that each battery quickly reaches an appropriate temperature.

[0005] An object of the present invention is to appropriately control the temperatures of a plurality of batteries. [Means for solving the problem]

[0006] One aspect of the present invention is a battery temperature control system for cooling a first battery with high internal resistance and a second battery with low internal resistance. The battery temperature control system includes a refrigerant supply source that supplies a refrigerant to the first battery and the second battery, a parallel refrigerant path that connects the refrigerant supply source to the first battery and the second battery in parallel, a series refrigerant path that connects the refrigerant supply source to the second battery via the first battery, and a supply path selection mechanism that selects the supply path of the refrigerant from the refrigerant supply source to the first battery and the second battery between the parallel refrigerant path and the series refrigerant path. Effect of the Invention

[0007] According to the present invention, the temperatures of a plurality of batteries can be appropriately controlled. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a block diagram showing an example of the configuration of a battery temperature control system according to the present embodiment. [Diagram 2] FIG. 2 is a diagram showing a schematic view, with thick lines, of the flow of the refrigerant when a series refrigerant path is formed in the refrigerant path. [Diagram 3] FIG. 3 is a diagram showing a schematic view, by thick lines, of the flow of the coolant when parallel coolant paths are formed in the coolant path. [Figure 4] FIG. 4 is a flowchart showing an example of a procedure of the battery temperature control process performed by the battery temperature control system. [Diagram 5] FIG. 5 is a block diagram showing an example of the configuration of a battery temperature control system according to the present embodiment. [Figure 6] FIG. 6 is a block diagram showing an example of the configuration of a battery temperature control system in this embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0010] [Example of battery cooling system configuration] 1 is a block diagram showing an example of the configuration of a battery temperature control system 1 in this embodiment. The battery temperature control system 1 is provided, for example, in an electric vehicle that includes a drive motor 2 (electric motor) as a driving source for traveling and can travel by the driving force of the drive motor 2. Such electric vehicles include electric vehicles (EVs) and hybrid electric vehicles (HEVs).

[0011] FIG. 2 is a diagram showing, with thick lines, a schematic flow of the refrigerant when a series refrigerant path is formed in the refrigerant path 20. FIG. 3 is a diagram showing, with thick lines, a schematic flow of the refrigerant when a parallel refrigerant path is formed in the refrigerant path 20. The series refrigerant path is a flow path in which the radiator 8, the first battery 6, and the second battery 7 are connected in series. The parallel refrigerant path is a flow path in which the radiator 8, the first battery 6, and the second battery 7 are connected in parallel. Switching between the series refrigerant path and the parallel refrigerant path will be described with reference to FIG. 1.

[0012] As shown in FIG. 1, the battery temperature control system 1 includes a drive motor 2, an inverter 3, a controller 4, a DC / DC converter 5, a first battery 6, a second battery 7, a radiator 8, a refrigerant path 20, a first valve 41, a second valve 42, and a third valve 43.

[0013] The drive motor 2 is driven to rotate by AC current supplied from the inverter 3, and transmits drive force to the drive wheels of the vehicle. The drive motor 2 is also configured to recover the kinetic energy of the vehicle as electric energy to the first battery 6 and the second battery 7 when the vehicle is decelerating, etc. In this way, the drive motor 2 functions as both a drive motor and a generator motor.

[0014] The inverter 3 is electrically connected to the drive motor 2, the first battery 6, and the second battery 7. Based on the control of the controller 4, the inverter 3 converts AC power generated by the drive motor 2 into DC power and supplies it to at least one of the first battery 6 and the second battery 7. Based on the control of the controller 4, the inverter 3 also converts DC power output from at least one of the first battery 6 and the second battery 7 into AC power and supplies it to the drive motor 2.

[0015] The controller 4 is a computer including, for example, a central processing unit (CPU), a read-only memory (ROM), a random access memory (RAM), and an input / output interface (I / O interface). The controller 4 also controls each part. For example, the controller 4 operates a first valve 41, a second valve 42, and a third valve 43 based on the battery temperatures of the first battery 6 and the second battery 7 to execute control for switching between a series refrigerant path and a parallel refrigerant path.

[0016] The DC / DC converter 5 is provided to match the output voltages of the first battery 6 and the second battery 7. Specifically, the DC / DC converter 5 performs voltage conversion to adjust and output the DC voltage exchanged between the inverter 3 and the second battery 7 under the control of the controller 4. Note that, although an example in which the DC / DC converter 5 is provided only for the second battery 7 is shown in this embodiment, a DC / DC converter may be provided only for the first battery 6, or a DC / DC converter may be provided for both the first battery 6 and the second battery 7.

[0017] The first battery 6 is an energy-specialized battery pack that uses cells with high internal resistance and high capacity density, in other words, the first battery 6 is a battery pack with high capacity characteristics.

[0018] The second battery 7 is a power-specialized battery pack using cells with low internal resistance and high output density. In other words, the second battery 7 is a battery pack with high output characteristics. The high and low internal resistances of the first battery 6 and the second battery 7 described here mean inherent values ​​when the first battery 6 and the second battery 7 are compared under the same conditions. In other words, they mean characteristics determined according to the individual differences of the first battery 6 and the second battery 7, not depending on the operating conditions (temperature, SOC, etc.) of the first battery 6 and the second battery 7. For example, since the internal resistances of the first battery 6 and the second battery 7 change depending on the operating conditions such as the temperature and SOC of the battery, it is assumed that the measured high and low internal resistances of the first battery 6 and the second battery 7 may be reversed depending on these changes. However, the high and low internal resistances of the first battery 6 and the second battery 7 mentioned in this specification do not depend on the reversal of the high and low relationship depending on this operating condition, except in cases where specifically excluded.

[0019] In this manner, this embodiment shows an example of a battery pack consisting of two battery packs with different internal resistances when compared under the same conditions. Also, by using a first battery 6 with high capacity characteristics and a second battery 7 with high output characteristics in parallel, a vehicle equipped with a battery with high capacity characteristics and high output characteristics can be realized.

[0020] In addition, the amount of heat W generated when the battery is charged or discharged can be calculated using the current value I [A] when the battery is charged or discharged and the internal resistance value R [Ω] of the battery according to the following formula 1. W=I 2 ×R…Formula 1

[0021] For this reason, when the current value during charging and discharging is the same, the first battery 6 with a high internal resistance will heat up faster than the second battery 7 with a low internal resistance. In this embodiment, an example is shown in which the heat generated by the first battery 6, which heats up faster than the second battery 7, is used to heat up the second battery 7. Specifically, the refrigerant circulating through the first battery 6 and the second battery 7 is used to supply the refrigerant, whose amount of heat has been increased by the heat of the first battery 6, to the second battery 7, and the increased amount of heat contained in the refrigerant is used to heat up the second battery 7.

[0022] The first battery 6 is also provided with a temperature sensor that detects the temperature related to the first battery 6. Temperature information detected by this temperature sensor is output to the controller 4. One or more temperature sensors can be installed in the first battery 6. The installation location of the temperature sensor in the first battery 6 can be appropriately set based on experimental data or the like. Similarly, the second battery 7 is also provided with one or more temperature sensors that detect the temperature related to the second battery 7.

[0023] The radiator 8 is a cooler attached to the front part of the vehicle, and is a device for dissipating heat of a refrigerant (for example, cooling water) to the air outside the vehicle. The radiator 8 is connected to a refrigerant passage 20. The radiator 8 is an example of a refrigerant supply source that supplies refrigerant to the first battery 6 and the second battery 7.

[0024] The coolant path 20 is a flow path for the coolant that circulates the coolant inside each battery or at a position close to each battery in order to cool the first battery 6 and the second battery 7, and is composed of a plurality of paths 21 to 28. In FIG. 1, the direction in which the coolant flows in the paths 21 to 28 is indicated typically by arrows. The coolant path 20 is also provided with a pump (not shown) that circulates the coolant based on the control of the controller 4. Specifically, the coolant cooled in the radiator 8 is circulated through the coolant path 20 by the pump, thereby cooling the first battery 6 and the second battery 7.

[0025] The first valve 41, the second valve 42, and the third valve 43 are valves that switch the supply path of the refrigerant in the refrigerant path 20. In other words, the first valve 41, the second valve 42, and the third valve 43 are valves that switch the flow direction of the refrigerant in the refrigerant path 20.

[0026] Specifically, the first valve 41 is a valve connected to the paths 21, 22, and 23. The first valve 41 is operated to either a closed state in which the flow of the refrigerant from the path 21 to the path 23 is stopped and the refrigerant flows from the path 21 to the path 22, or an open state in which the refrigerant flows from the path 21 to both the paths 22 and 23.

[0027] In addition, the second valve 42 is a valve connected to the paths 23, 24, and 26. The second valve 42 is operated to either a closed state in which the flow of the refrigerant from the path 24 is stopped and the refrigerant flows from the path 23 to the path 26, or an open state in which the refrigerant flows from the path 24 to the path 26.

[0028] Further, the third valve 43 is a valve connected to the paths 25, 27, and 28. The third valve 43 is operated to either a closed state in which the flow of the refrigerant from the path 25 is stopped and the refrigerant flows from the path 27 to the path 28, or an open state in which the refrigerant from both the paths 25 and 27 flows to the path 28.

[0029] In FIG. 2, the flow of the refrigerant in the refrigerant passage 20 when the first valve 41 and the third valve 43 are closed and the second valve 42 is open is indicated by a thick line. In this manner, by controlling the first valve 41, the second valve 42, and the third valve 43, a series refrigerant passage is formed that connects the radiator 8, the first battery 6, and the second battery 7 in series. Specifically, the series refrigerant passage is formed so that the refrigerant flows through the paths 21, 22, 24, 26, 27, and 28 in this order. In addition, this series refrigerant passage is formed so that the first battery 6 is located upstream of the second battery 7 when the radiator 8 is assumed to be on the upstream side. That is, the refrigerant from the radiator 8 is supplied to the first battery 6, which generates a large amount of heat, via the paths 21 and 22. The amount of heat generated in the first battery 6 is given to the refrigerant supplied to the first battery 6. Then, the refrigerant whose amount of heat has increased due to the heat of the first battery 6 is supplied to the second battery 7 via the paths 24 and 26. In this way, by forming a serial coolant path, the amount of heat held by the coolant, which has increased due to the heat of the first battery 6, is used to increase the temperature of the second battery .

[0030] In FIG. 3, the flow of the refrigerant in the refrigerant passage 20 when the first valve 41 and the third valve 43 are in an open state and the second valve 42 is in a closed state is indicated by a thick line. In this manner, by controlling the first valve 41, the second valve 42, and the third valve 43, a parallel refrigerant passage is formed that connects the radiator 8 to the first battery 6 and the second battery 7 in parallel. Specifically, the parallel refrigerant passage is formed by two passages, a passage for cooling the first battery 6 and a passage for cooling the second battery 7. The passage for cooling the first battery 6 is configured so that the refrigerant flows through the paths 21, 22, 25, and 28 in this order. The passage for cooling the second battery 7 is configured so that the refrigerant flows through the paths 21, 23, 26, 27, and 28 in this order.

[0031] In this way, the first valve 41, the second valve 42, and the third valve 43 function as a supply path selection mechanism that selects between the parallel refrigerant path and the series refrigerant path. In the configuration example shown in Figures 1 to 3, at least some of the paths (paths 21, 22, 26, 27, and 28) of the parallel refrigerant path and the series refrigerant path are used in common. A method of switching between the parallel refrigerant path and the series refrigerant path will be described with reference to Figure 4.

[0032] [Example of battery temperature control system operation] 4 is a flowchart showing an example of a procedure for battery temperature control processing by the battery temperature control system 1. This procedure is executed based on a program stored in a storage unit (not shown). This procedure is also executed repeatedly at a predetermined calculation cycle.

[0033] In step S201, the controller 4 acquires the temperatures of the first battery 6 and the second battery 7. That is, the controller 4 acquires a temperature T1 detected by a temperature sensor attached to the first battery 6 and a temperature T2 detected by a temperature sensor attached to the second battery 7.

[0034] In step S202, the controller 4 determines whether or not at least one of the temperatures T1 and T2 is lower than the target heating temperature. The target heating temperature is a temperature set to prevent a decrease in the charge / discharge characteristics of the battery due to a decrease in the battery temperature. That is, by setting the battery temperatures of both the first battery 6 and the second battery 7 to be equal to or higher than the target heating temperature, the charge / discharge characteristics of both the first battery 6 and the second battery 7 can be maintained. The target heating temperature can be appropriately set based on experimental data or the like. In addition, in this embodiment, an example is shown in which the target heating temperatures of the first battery 6 and the second battery 7 are set to the same value, but different values ​​may be set as the target heating temperatures of the first battery 6 and the second battery 7. In this case, it is preferable to set the target heating temperature of the second battery 7 to a value lower than that of the first battery 6.

[0035] In step S202, if it is determined that at least one of the temperatures T1 and T2 is lower than the target heating temperature, the process proceeds to step S203. On the other hand, if it is determined that both of the temperatures T1 and T2 are equal to or higher than the target heating temperature, the process proceeds to step S204.

[0036] In step S203, the controller 4 executes control to operate the first valve 41, the second valve 42, and the third valve 43 so as to form a series refrigerant path in the refrigerant path 20. Specifically, the controller 4 executes control to close the first valve 41 and the third valve 43, and open the second valve 42. When each valve is controlled in this manner, a series refrigerant path is formed in which the radiator 8, the first battery 6, and the second battery 7 are connected in series, as shown by the thick line in FIG.

[0037] In this manner, when a series refrigerant path is formed in the refrigerant path 20, the controller 4 adjusts the flow rate of the refrigerant so that the refrigerant whose heat content has increased due to the heat of the first battery 6 is appropriately supplied to the second battery 7.

[0038] In this way, when the serial coolant path is formed in the coolant path 20, the coolant is supplied first to the first battery 6 which generates a large amount of heat, and heat is given to the coolant. Then, the coolant whose heat content has increased due to the heat of the first battery 6 is supplied to the second battery 7, and the increased heat content of the coolant is used to raise the temperature of the second battery 7. Therefore, while suppressing the spread of the temperature difference between the first battery 6 and the second battery 7, the temperature rise speed of the second battery 7 can be increased, and the temperature rise process of the entire system can be made more rapid. In particular, by selecting the serial coolant path in a scene where either one of the first battery 6 and the second battery 7 has not reached the target temperature rise, the temperature rise of the first battery 6 and the second battery 7 can be made more rapid.

[0039] In step S204, the controller 4 executes control to operate the first valve 41, the second valve 42, and the third valve 43 so as to form a parallel refrigerant path in the refrigerant path 20. Specifically, the controller 4 executes control to open the first valve 41 and the third valve 43, and close the second valve 42. When each valve is controlled in this manner, a parallel refrigerant path is formed in which the radiator 8 is connected in parallel to each of the first battery 6 and the second battery 7, as shown by the thick lines in FIG.

[0040] In this way, when a parallel coolant path is formed in the coolant path 20, the controller 4 adjusts the flow rate of the coolant so that the coolant from the radiator 8 is appropriately supplied to both the first battery 6 and the second battery 7.

[0041] In this way, when a parallel coolant path is formed in the coolant path 20, the coolant from the radiator 8 is supplied in parallel to both the first battery 6 and the second battery 7, so that the first battery 6 and the second battery 7 can be appropriately cooled. In particular, when the warm-up of both the first battery 6 and the second battery 7 is completed, the parallel coolant path is selected, so that the coolant is directly supplied from the radiator 8 to both batteries. This makes it possible to speed up the cooling process that is performed after the warm-up process.

[0042] 4 controls the temperatures of the first battery 6 and the second battery 7 by supplying refrigerant from the radiator 8 to the first battery 6 and the second battery 7. Furthermore, when the temperature of the second battery 7 is lower than the target warm-up temperature, the controller 4 supplies the refrigerant to the second battery 7 via the first battery 6, and when the temperature of the second battery 7 is equal to or higher than the target warm-up temperature, the controller 4 supplies the refrigerant to the first battery 6 and the second battery 7 in parallel.

[0043] [Modification of the refrigerant path] 5 and 6 are block diagrams showing a configuration example of a battery temperature control system 10 in this embodiment. The battery temperature control system 10 is an example in which a part of the refrigerant passage 20 shown in FIG. 1 is modified. Specifically, the battery temperature control system 10 differs from the battery temperature control system 1 shown in FIG. 1 in that a refrigerant passage 50 is provided instead of the refrigerant passage 20, and a first valve 71, a second valve 72, a third valve 73, and a fourth valve 74 are provided instead of the first valve 41, the second valve 42, and the third valve 43. For this reason, the following description will focus on the parts that are different from the battery temperature control system 1, and the parts corresponding to FIG. 1 will be denoted by the same reference numerals as in FIG. 1 and some of the description will be omitted.

[0044] 5, the flow of refrigerant is shown by thick lines when a series refrigerant path is formed in refrigerant path 50 by operating first valve 71, second valve 72, third valve 73, and fourth valve 74. Specifically, as shown by thick lines, a series refrigerant path is formed by paths 51, 52, 56, 57, 59, and 60.

[0045] 6 shows, with thick lines, a schematic representation of the flow of refrigerant when a parallel refrigerant path is formed in the refrigerant path 50 by operating the first valve 71, the second valve 72, the third valve 73, and the fourth valve 74. Specifically, as shown by the thick lines, a parallel refrigerant path is formed by two paths: a path for cooling the first battery 6 and a path for cooling the second battery 7. The path for cooling the first battery 6 is made up of paths 51, 53, 54, 58, and 60. The path for cooling the second battery 7 is made up of paths 51, 53, 55, 57, 59, and 60.

[0046] As shown in Figures 2, 3, 5, and 6, various types of refrigerant paths can be used to form the series refrigerant paths and the parallel refrigerant paths. The refrigerant paths 20 and 50 are examples of refrigerant paths that can form the series refrigerant paths and the parallel refrigerant paths, and other refrigerant paths may be used. In the configuration examples shown in Figures 1 to 3, 5, and 6, examples are shown in which at least some of the parallel refrigerant paths and the series refrigerant paths are shared, but all of the parallel refrigerant paths and the series refrigerant paths may be dedicated paths and not shared paths.

[0047] In this embodiment, the battery temperature control system 1 including two batteries (the first battery 6 and the second battery 7) has been described as an example, but this embodiment can also be applied to a battery temperature control system including three or more batteries. For example, a battery temperature control system including a first battery having the highest internal resistance, a second battery having the second highest internal resistance, and a third battery having the lowest internal resistance is assumed. In this battery temperature control system, when at least one of the battery temperatures of the first to third batteries is lower than the target heating temperature, a series refrigerant path is formed. In this series refrigerant path, the refrigerant path is formed so that the first battery is located upstream, the second battery is located midstream, and the third battery is located downstream. On the other hand, when all of the battery temperatures of the first to third batteries are equal to or higher than the target heating temperature, a parallel refrigerant path is formed.

[0048] More generally, for example, a battery temperature control system having i batteries (where i≧3) is assumed. In this battery temperature control system, k batteries (where i≧k≧1) including the battery with the largest internal resistance among the i batteries are defined as a first battery group, and j batteries (where j≧1 and j=ik) including the battery with the smallest internal resistance among the i batteries are defined as a second battery group. The internal resistance of each battery included in the first battery group is greater than the internal resistance of each battery included in the second battery group. In addition, in this battery temperature control system, the temperature of each battery is controlled by supplying a coolant from a radiator to each battery included in each of the first battery group and the second battery group. In addition, this battery temperature control system is provided with a parallel coolant path that connects the radiator to each of the first battery group and the second battery group in parallel, and a series coolant path that connects the radiator to the second battery group via the first battery group. The battery temperature control system further includes one or more valves for selecting a coolant supply path from the radiator to the first battery group and the second battery group between a parallel coolant path and a series coolant path. In the battery temperature control system, the controller controls the coolant to be supplied to the second battery group via the first battery group when the temperature of the battery with the smallest internal resistance included in the second battery group is lower than the target warm-up temperature. On the other hand, the controller controls the coolant to be supplied in parallel to the first battery group and the second battery group when the temperature of the battery with the smallest internal resistance included in the second battery group is equal to or higher than the target warm-up temperature.

[0049] Here, in order to use EVs (Electric Vehicles) in cold regions, the battery warming function using a PTC heater is being installed. However, the use of a PTC heater may cause the battery's power consumption to deteriorate. Therefore, in this embodiment, the circulation of the refrigerant is utilized to utilize the heat generated by a battery with high internal resistance to warm up a battery with low internal resistance, thereby reducing the use of the PTC heater. For example, due to differences in characteristics (e.g., heat generation amount, heat extraction and heat reception amount, heat capacity) determined according to individual differences of the multiple batteries, differences in temperature rise occur when the multiple batteries are warmed up. Therefore, when each battery is warmed up, the parallel refrigerant path is switched to a serial refrigerant path, and the heat generated by the battery with high internal resistance is utilized to warm up the battery with low internal resistance by utilizing the temperature difference between the batteries. This allows the temperature of even a battery with low internal resistance to be quickly raised. That is, the temperature of multiple batteries can be appropriately controlled. In addition, since the circulation of the refrigerant can be utilized, existing parts can be utilized, and the cost increase of additional parts can be suppressed.

[0050] [Configuration and Effects of This Embodiment] The battery temperature control system 1 according to this embodiment is a battery temperature control system that cools a first battery 6 having a high internal resistance and a second battery 7 having a low internal resistance. The battery temperature control system 1 includes a radiator 8 (an example of a refrigerant supply source) that supplies a refrigerant to the first battery 6 and the second battery 7, a parallel refrigerant path (a parallel refrigerant path formed by paths 21, 22, 23, 25, 26, 27, and 28 shown in thick lines in FIG. 3) that connects the radiator 8 to the first battery 6 and the second battery 7 in parallel, a series refrigerant path (a series refrigerant path formed by paths 21, 22, 24, 26, 27, and 28 shown in thick lines in FIG. 2) that connects the radiator 8 to the second battery 7 via the first battery 6, and a supply path selection mechanism (a first valve 41, a second valve 42, and a third valve 43) that selects the supply path of the refrigerant from the radiator 8 to the first battery 6 and the second battery 7 between the parallel refrigerant path and the series refrigerant path.

[0051] According to the battery temperature control system 1, when the series coolant path is selected, the coolant is supplied to the first battery 6, which generates a large amount of heat, first, and heat is imparted to the coolant. Then, the coolant with an increased amount of heat due to the heat of the first battery 6 is supplied to the second battery 7, and the increased amount of heat of the coolant is used to raise the temperature of the second battery 7. Therefore, the temperature rise rate of the second battery 7 can be increased while suppressing the spread of the temperature difference between the first battery 6 and the second battery 7, and the temperature rise process of the entire system can be made faster. Furthermore, when the parallel coolant path is selected, the coolant from the radiator 8 is supplied to both the first battery 6 and the second battery 7 in parallel, so that the first battery 6 and the second battery 7 can be appropriately cooled.

[0052] Moreover, the battery temperature control system 1 according to this embodiment further includes a controller 4 (an example of a control device) that operates the supply path selection mechanism based on the battery temperature of at least one of the first battery 6 and the second battery 7. Furthermore, when the battery temperature is lower than the target heating temperature, the controller 4 operates the supply path selection mechanism so that the serial refrigerant path is selected as the supply path.

[0053] According to such a battery temperature control system 1, in a scene where either the first battery 6 or the second battery 7 has not reached the target heating temperature, the serial refrigerant path is selected, thereby speeding up the heating of the first battery 6 and the second battery 7.

[0054] Furthermore, in the battery temperature control system 1 of this embodiment, when the battery temperatures of both the first battery 6 and the second battery 7 reach the target heating temperature, the controller 4 operates the supply path selection mechanism so that the parallel refrigerant path is selected as the supply path.

[0055] According to the battery temperature control system 1, in a scene where the heating of both the first battery 6 and the second battery 7 is completed, the parallel refrigerant path is selected, so that the refrigerant is directly supplied from the refrigerant supply source to both batteries. Therefore, the cooling process performed after the heating process can be accelerated.

[0056] The battery temperature control method according to the present embodiment controls the temperatures of the first battery 6 and the second battery 7 by supplying refrigerant from a radiator 8 (an example of a refrigerant supply source) to the first battery 6 having a high internal resistance and the second battery 7 having a low internal resistance. In this battery temperature control method, if the temperature of the second battery 7 is lower than the target heating temperature in step S202 (or if the temperature of at least one of the first battery 6 and the second battery 7 is lower than the target heating temperature), the refrigerant is supplied to the second battery 7 via the first battery 6 in step S203. If the temperature of the second battery 7 is equal to or higher than the target heating temperature in step S202 (or if the temperatures of both the first battery 6 and the second battery 7 are equal to or higher than the target heating temperature), the refrigerant is supplied in parallel to the first battery 6 and the second battery 7 in step S204.

[0057] According to this battery temperature control method, when the coolant is supplied to the second battery 7 via the first battery 6, the coolant is supplied first to the first battery 6 which generates a large amount of heat, and heat is given to the coolant. Then, the coolant whose heat content has increased due to the heat of the first battery 6 is supplied to the second battery 7, and the increased heat content of the coolant is used to raise the temperature of the second battery 7. Therefore, the temperature rise rate of the second battery 7 can be increased while suppressing the spread of the temperature difference between the first battery 6 and the second battery 7, and the temperature rise process of the entire system can be made faster. In addition, when the coolant is supplied to the first battery 6 and the second battery 7 in parallel, the coolant from the radiator 8 is supplied to both the first battery 6 and the second battery 7 in parallel, so that the first battery 6 and the second battery 7 can be appropriately cooled.

[0058] Each process shown in the present embodiment is executed based on a program for causing a computer to execute each processing procedure. Therefore, the present embodiment can also be understood as an embodiment of a program for realizing a function for executing each process, and a recording medium for storing the program. For example, the program can be stored in a storage device of the vehicle by an update operation for adding a new function to the vehicle. This makes it possible to execute each process shown in the present embodiment on the updated vehicle. The update can be performed, for example, during a regular inspection of the vehicle. The program may also be updated by wireless communication.

[0059] Although the embodiments of the present invention have been described above, the above-mentioned embodiments merely show some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above-mentioned embodiments. [Explanation of symbols]

[0060] 1, 10 Battery temperature control system, 2 Drive motor, 3 Inverter, 4 Controller, 5 DC / DC converter, 6 First battery, 6 Second battery, 7 Radiator, 20, 50 Coolant path, 21-28, 51-60 Path, 41, 71 First valve, 42, 72 Second valve, 43, 73 Third valve, 74 Fourth valve

Claims

1. A battery temperature control system for cooling a first battery having a high internal resistance and a second battery having a low internal resistance, a refrigerant supply source that supplies a refrigerant to the first battery and the second battery; a parallel coolant passage that connects the coolant supply source to the first battery and the second battery in parallel; a serial coolant passage that connects the coolant supply source to the second battery via the first battery; a supply path selection mechanism that selects a supply path of the coolant from the coolant supply source to the first battery and the second battery between the parallel coolant path and the series coolant path. Battery temperature control system.

2. 2. The battery temperature control system of claim 1, a control device that operates the supply path selection mechanism based on a battery temperature of at least one of the first battery and the second battery; The control device includes: When the battery temperature is lower than a target heating temperature, the supply path selection mechanism is operated so that the series refrigerant path is selected as the supply path. Battery temperature control system.

3. 3. The battery temperature control system of claim 2, The control device includes: when the battery temperatures of both the first battery and the second battery reach the target heating temperature, the supply path selection mechanism is operated so that the parallel refrigerant path is selected as the supply path. Battery temperature control system.

4. 1. A battery temperature control method for controlling temperatures of a first battery having a high internal resistance and a second battery having a low internal resistance by supplying a refrigerant from a refrigerant supply source to the first battery and the second battery, When the temperature of the second battery is lower than a target heating temperature, the refrigerant is supplied to the second battery via the first battery; When the temperature of the second battery is equal to or higher than the target temperature rise temperature, the refrigerant is supplied in parallel to the first battery and the second battery. Battery temperature control method.

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