Control device and control method

Abstract

A control device (1) controls an electric compressor included in a refrigeration cycle that uses a secondary refrigerant cycle for cooling cooling water that circulates in a cooling water circuit for performing heat exchange between a battery (2) and the cooling water. The control device (1) includes an acquisition section (201) for acquiring a temperature in a single cell, a determination section (202) for determining a charge rate of the battery, and a cooling control section (204) for determining a cooling start single cell temperature based on the charge rate determined by the determination section (202), and causing the electric compressor to operate to start cooling the cooling water using the secondary refrigerant on a condition that the temperature acquired by the acquisition section (201) is higher than the determined cooling start single cell temperature. The cooling control section (204) determines a higher cooling start single cell temperature in a case where the determination section (202) determines a first charge rate than in a case where the determination section (202) determines a second charge rate that is higher than the first charge rate.

Description

Technical Field

[0001] This disclosure relates to a control device and control method for controlling a device for cooling a battery. Background Technology

[0002] To prevent the batteries installed in electric vehicles from deteriorating during driving, a solution for cooling the batteries has been proposed (e.g., Patent Document 1).

[0003] Existing technology

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2014-043181 Summary of the Invention

[0006] The technical problem that the invention aims to solve

[0007] In the technology described in Patent Document 1, the battery is cooled by heat exchange between the cooling water circulating in the cooling water circuit and the battery. The cooled water after heat exchange is then cooled again by low-pressure refrigerant circulating in the refrigeration cycle within the refrigerator. In the technology described in Patent Document 1, the electric compressor, which is a component of the refrigeration cycle, consumes more electricity.

[0008] This disclosure is made in view of these problems, and its purpose is to provide a technique that can reduce the power required to cool a battery.

[0009] means for solving problems

[0010] According to a first aspect of this disclosure, a control device controls an electric compressor included in a refrigeration cycle for circulating and cooling a secondary refrigerant that exchanges heat with cooling water in a battery. The control device includes: an acquisition unit that acquires the temperature of a single cell in the battery; a determination unit that determines the charge level of the battery; and a cooling control unit that determines a cooling start single cell temperature based on the charge level determined by the determination unit, and operates the electric compressor to begin cooling the cooling water using the secondary refrigerant if the temperature acquired by the acquisition unit is higher than the determined cooling start single cell temperature. The cooling control unit determines a higher cooling start single cell temperature when the determination unit determines a first charge level than if the determination unit determines a second charge level higher than the first charge level.

[0011] The cooling control unit can use secondary refrigerant to cool the cooling water, ensuring that the temperature inside the single cell does not exceed a predetermined upper limit temperature during the period before the battery is depleted. The cooling control unit can use a refrigerator that exchanges heat between the cooling water and the secondary refrigerant to cool the cooling water, and can alternate between an open state (refrigerant expansion valve open) and a closed state (refrigerant expansion valve closed) to control the amount of cooling water cooled by the secondary refrigerant supplied to the refrigerator through the refrigerant expansion valve. It can also determine the ratio of the time the refrigerant expansion valve is open to the total time period, ensuring that the temperature inside the single cell remains below the upper limit temperature during the period before the battery is depleted.

[0012] The control device may also include an air conditioning control unit that reduces the internal temperature of the evaporator included in the refrigeration cycle by heat exchange between the secondary refrigerant and the internal air, and stops the heat exchange between the secondary refrigerant and the internal air by a stop time period shorter than the predetermined time period when the cooling control unit is using the secondary refrigerant to cool the cooling water, provided that the temperature obtained by the acquisition unit is higher than the transition temperature.

[0013] The control device may further include an output detection unit that detects the battery output, wherein when the battery output is equal to or less than a reference value, the air conditioning control unit needs to continue the heat exchange between the secondary refrigerant and the internal air. The determination unit can determine the degree of battery degradation, and when the determination unit determines a first degree of degradation, the cooling control unit can determine a higher cooling start single-cell temperature than if the determination unit determines a second charge level higher than the first charge level.

[0014] The acquisition unit acquires the first water temperature of the coolant measured by a first water temperature sensor and the second water temperature measured by a second water temperature sensor. The first water temperature sensor is located upstream of the radiator in the cooling water circuit, which facilitates heat exchange between the coolant and the outside air. The cooling water circuit facilitates heat exchange between the battery and the coolant. The second water temperature sensor is located downstream of the radiator. Additionally, the control device includes a switching control unit. When the value obtained by subtracting the second water temperature from the first water temperature is equal to or greater than a first reference value, the switching control unit controls a switching unit to switch the flow path of the coolant so that the coolant circulates in the first cooling water circuit through the radiator. Conversely, when the value obtained by subtracting the second water temperature from the first water temperature is less than a second reference value (which is smaller than the first reference value), the switching control unit controls the switching unit to circulate the coolant in a second cooling water circuit that does not pass through the radiator. The cooling control unit can determine the estimated arrival time of the vehicle equipped with the control device at its destination and can use secondary refrigerant to cool the coolant, thereby reducing the temperature within each individual cell in the battery to below a predetermined pre-stop temperature before the estimated arrival time. The acquisition unit can acquire the temperature of multiple individual cells of the battery, and the cooling control unit can start cooling the cooling water using secondary refrigerant when the highest temperature among the individual cell temperatures acquired by the acquisition unit is higher than the temperature of the individual cell at which cooling begins.

[0015] According to a second aspect of this disclosure, a control method is used to control an electric compressor included in a refrigeration cycle for circulating secondary refrigerant to cool cooling water that exchanges heat with a battery. The control method includes the following steps: acquiring the temperature of a single cell in the battery; determining the charge level of the battery; determining a cooling start temperature for the single cell based on the determined charge level; and, if the acquired temperature is higher than the determined cooling start temperature for the single cell, initiating cooling of the cooling water using secondary refrigerant by operating the electric compressor. In the step of determining the cooling start temperature for the single cell, when a first charge level is determined, a higher cooling start temperature for the single cell is determined than when a second charge level is determined, wherein the second charge level is higher than the first charge level.

[0016] The effects of the invention

[0017] According to this disclosure, it is possible to reduce the power required to cool the battery. Attached Figure Description

[0018] Figure 1 An overview of a vehicle equipped with a control device according to an embodiment is shown.

[0019] Figure 2 The main configuration of the vehicle is shown.

[0020] Figure 3This is a graph showing the relationship between the initial temperature of a single cell when cooling begins, the amount of charge in the cell, and the degree of cell degradation.

[0021] Figure 4 This illustrates the relationship between the temperature of a single cell in the battery and the operation of the cooling control unit.

[0022] Figure 5 This illustrates an example of the cooling control unit using secondary refrigerant to cool the cooling water.

[0023] Figure 6 An example is shown where the refrigerant expansion valve is controlled by the air conditioning control unit.

[0024] Figure 7 An example of using a switching control unit to control a switching unit is shown.

[0025] Figure 8 An example of using a switching control unit to control a switching unit is shown.

[0026] Figure 9 This is a flowchart illustrating the process by which the control device uses secondary refrigerant to cool the cooling water. Detailed Implementation

[0027] [Overview of Vehicle 100]

[0028] Figure 1 This diagram shows an overview of a vehicle 100 equipped with a control device 1 according to this embodiment. In the cooling water circuit that uses cooling water to cool the battery 2 during discharge or charging, the control device 1 of this embodiment uses a secondary refrigerant to cool the cooling water. The control device 1 can reduce the power required to cool the battery 2 by changing the time when to start using the secondary refrigerant to cool the cooling water according to the charge level (i.e., state of charge) of the battery 2.

[0029] The vehicle 100 includes a control device 1, a battery 2, a radiator 3, a radiator fan 4, a switching unit 5, a pump 6, a refrigerator 7, a water temperature sensor 8, a water temperature sensor 9, an electric compressor 11, a condenser 12, a condenser fan 13, a refrigerant expansion valve 14, an evaporator 15, a blower fan 16, and a refrigerant expansion valve 17.

[0030] For example, battery 2 is a lithium-ion battery used in electric vehicles. Battery 2 generates heat during discharge and charging. Battery 2 is cooled by heat exchange with cooling water circulating in a cooling water circuit. Figure 1 The upper side shows the cooling water circuit. The cooling water circuit facilitates heat exchange between battery 2 and cooling water, and circulates the cooling water within the cooling water circuit.

[0031] Radiator 3 facilitates heat exchange between cooling water and outside air in the cooling water circuit. Radiator fan 4 rotates to generate airflow through radiator 3, thereby cooling the cooling water passing through radiator 3.

[0032] Switching unit 5 switches the cooling water flow path. Figure 1 In the example shown, switching unit 5 is a valve used to switch whether cooling water flows through radiator 3. Pump 6 generates cooling water flow in the cooling water circuit. Refrigerator 7 cools the cooling water through heat exchange between the cooling water and the secondary refrigerant. Refrigerator 7 causes (i) a mist of the low-temperature, low-pressure secondary refrigerant passing through refrigerant expansion valve 17 to exchange heat with (ii) the high-temperature cooling water, thereby causing the secondary refrigerant to evaporate. The secondary refrigerant cools the cooling water by carrying away heat from the surrounding cooling water during evaporation.

[0033] Water temperature sensor 8 (equivalent to the first water temperature sensor) is located upstream of radiator 3 in the cooling water circuit. Water temperature sensor 8 measures the initial water temperature of the cooling water flowing into radiator 3. Water temperature sensor 9 (equivalent to the second water temperature sensor) is located downstream of radiator 3 in the cooling water circuit. Water temperature sensor 9 measures the second water temperature of the cooling water in radiator 3 after heat exchange with the outside air.

[0034] Figure 1 The lower side shows a refrigeration cycle involving the repeated evaporation and condensation of the secondary refrigerant. This refrigeration cycle circulates the secondary refrigerant to cool the cooling water. The electric compressor 11 compresses the low-temperature, low-pressure secondary refrigerant, which evaporates through heat exchange with the cooling water in the refrigerator 7, bringing it to a high-temperature, high-pressure state. The condenser 12 cools and condenses the high-temperature, high-pressure secondary refrigerant using cooling air generated by the condenser fan 13.

[0035] The refrigerant expansion valve 14, evaporator 15, and blower fan 16 are located inside the vehicle 100. The refrigerant expansion valve 14 forces liquid secondary refrigerant condensed by the condenser 12 through a small orifice, causing the secondary refrigerant to expand and become a low-temperature, low-pressure mist. The refrigerant expansion valve 14 supplies this low-temperature, low-pressure secondary refrigerant mist to the evaporator 15. Based on a control signal from the control device 1, the refrigerant expansion valve 14 switches between an open state (supplying secondary refrigerant to the evaporator 15) and a closed state (not supplying secondary refrigerant to the evaporator 15).

[0036] The evaporator 15 facilitates heat exchange between the low-temperature, low-pressure secondary refrigerant mist passing through the refrigerant expansion valve 14 and the air inside the vehicle, causing the secondary refrigerant to evaporate. The secondary refrigerant removes heat from the air inside the vehicle through evaporation, thereby lowering the temperature inside the vehicle. The blower fan 16 generates airflow, causing the air inside the vehicle to pass through the evaporator 15 and exchange heat between the secondary refrigerant and the air inside the vehicle.

[0037] Similar to the refrigerant expansion valve 14 described above, the refrigerant expansion valve 17 forcibly injects liquid secondary refrigerant through a small orifice, causing the secondary refrigerant to expand and become misty and at low temperature and low pressure. The refrigerant expansion valve 17 supplies this misty, low-temperature, low-pressure secondary refrigerant to the refrigerator 7. Based on a control signal from the control device 1, the refrigerant expansion valve 17 switches between an open state (supplying secondary refrigerant to the refrigerator 7) and a closed state (not supplying secondary refrigerant to the refrigerator 7).

[0038] For example, control device 1 is an electronic control unit (ECU). Control device 1 controls the cooling of cooling water by radiator 3. Control device 1 controls the electric compressor 11 included in the refrigeration cycle for secondary refrigerant circulation. Control device 1 measures the terminal voltage of battery 2 and determines the charge level of battery 2 based on the measured terminal voltage. Control device 1 acquires the temperature inside each cell of battery 2, as measured by a cell temperature sensor disposed within each cell of battery 2.

[0039] The control device 1 determines the starting temperature of the cooling cell for initiating cooling of the cooling water using secondary refrigerant based on the determined charge level of the battery 2. At this time, the higher the determined charge level of the battery 2, the lower the cooling starting temperature determined by the control device 1. If the temperature inside the single cell is higher than the determined cooling starting temperature, the control device 1 operates the electric compressor 11 to cool the cooling water using secondary refrigerant.

[0040] Even when control device 1 is using secondary refrigerant to cool the cooling water, the temperature inside each cell of battery 2 will rise. However, when the charge level of battery 2 is low, the battery is likely to deplete before the temperature inside each cell rises. Therefore, when the charge level of battery 2 is low, control device 1 determines that the high temperature is the starting temperature for cooling the individual cells of battery 2. In this way, control device 1 delays the time for using secondary refrigerant to cool the cooling water, thereby reducing the power required to cool battery 2.

[0041] Conversely, when battery 2 has a high charge level, there is a possibility that the temperature inside each cell of battery 2 may rise due to prolonged operation. Therefore, control device 1 determines the low temperature as the starting temperature for cooling each cell of battery 2. In this way, control device 1 starts cooling battery 2 with secondary refrigerant as early as possible, thereby preventing the temperature inside each cell of battery 2 from rising.

[0042] [Vehicle Configuration]

[0043] Figure 2 The main configuration of vehicle 100 is shown. Vehicle 100 includes a control unit 1, a switching unit 5, a water temperature sensor 8, a water temperature sensor 9, a refrigerant expansion valve 14, a refrigerant expansion valve 17, a single battery temperature sensor 21, a voltage sensor 22, and a current sensor 23. The control unit 1 includes a storage unit 101 and a control unit 102.

[0044] A single-cell temperature sensor 21 measures the temperature inside each of the individual cells in battery 2. Multiple single-cell temperature sensors 21 are disposed at each of the multiple individual cells in battery 2. It is assumed that the multiple single-cell temperature sensors 21 are configured for each individual cell. Preferably, the single-cell temperature sensor 21 is disposed at the location within the individual cell where the temperature is highest. The single-cell temperature sensor 21 inputs the measured temperature within the individual cell to the acquisition unit 201.

[0045] Voltage sensor 22 measures the terminal voltage of battery 2. Voltage sensor 22 inputs the measurement result of the terminal voltage of battery 2 to determination unit 202 and output detection unit 203. Current sensor 23 measures the current flowing through battery 2. Current sensor 23 inputs the current measurement result to determination unit 202 and output detection unit 203.

[0046] For example, the storage unit 101 includes a read-only memory (ROM) and a random access memory (RAM). The storage unit 101 stores various programs and various types of data for enabling the control unit 102 to function. By executing the programs stored in the storage unit 101, the control unit 102 functions as an acquisition unit 201, a determination unit 202, an output detection unit 203, a cooling control unit 204, an air conditioning control unit 205, and a switching control unit 206.

[0047] The acquisition unit 201 acquires the temperature inside each individual cell of battery 2. For example, the acquisition unit 201 acquires the temperature inside each individual cell of battery 2 as measured by the individual cell temperature sensor 21 for each individual cell. The acquisition unit 201 acquires the first water temperature of the cooling water as measured by the water temperature sensor 8 (equivalent to the first water temperature sensor) located upstream of the radiator 3. The acquisition unit 201 acquires the second water temperature of the cooling water as measured by the water temperature sensor 9 (equivalent to the second water temperature sensor) located downstream of the radiator 3. The acquisition unit 201 outputs information indicating the acquired temperature inside each individual cell to the cooling control unit 204 and the air conditioning control unit 205. The acquisition unit 201 outputs information indicating the acquired first and second water temperatures to the switching control unit 206.

[0048] The determination unit 202 determines the amount of charge on the battery 2. For example, based on the terminal voltage of the battery 2 measured by the voltage sensor 22, the determination unit 202 determines the amount of decrease in the terminal voltage of the battery 2 from a fully charged state. The determination unit 202 determines the amount of charge on the battery 2 based on the determined amount of decrease in the terminal voltage of the battery 2.

[0049] The determination unit 202 determines the degree of degradation of the battery 2, such as a decrease in capacity or an increase in internal resistance. The determination unit 202 measures the voltage and current of the battery 2 using the voltage sensor 22 and the current sensor 23 respectively, and analyzes the voltage and current waveforms of the battery 2 to determine the degree of degradation of the battery 2. The determination unit 202 outputs information indicating the determined degree of degradation to the cooling control unit 204.

[0050] The output detection unit 203 detects the output of the battery 2. For example, the output of the battery 2 is the power supplied from the battery 2. For example, the output detection unit 203 detects the output of the battery 2 based on the terminal voltage of the battery 2 measured by the voltage sensor 22 and the current flowing through the battery 2 measured by the current sensor 23. The output detection unit 203 notifies the air conditioning control unit 205 of the detected output of the battery 2.

[0051] [Determination of single-cell temperature upon cooling start]

[0052] The cooling control unit 204 controls the cooling of the cooling water using a secondary refrigerant. First, the cooling control unit 204 determines the starting temperature of the cooling cell for initiating the cooling of the cooling water using the secondary refrigerant. In the example of this specification, the cooling control unit 204 determines the starting temperature of the cooling cell based on the charge level determined by the determination unit 202. Figure 3 The relationship between the cooling start temperature of the single cell, the charge level of the battery 2, and the degree of degradation of the battery 2, as determined by the cooling control unit 204, is shown. Figure 3 The vertical axis represents the temperature at which cooling begins in a single cell. Figure 3 The horizontal axis represents the charge level of battery 2. Figure 3The three lines shown represent the single-cell cooling start temperature when the degree of degradation of battery 2 determined by determination unit 202 is higher than a predetermined reference level, the single-cell cooling start temperature when the degree of degradation of battery 2 is equal to the reference level, and the single-cell cooling start temperature when the degree of degradation of battery 2 determined by determination unit 202 is lower than the reference level.

[0053] like Figure 3 As shown, the lower the charge level determined by the determination unit 202, the higher the single-cell temperature at which cooling begins, as determined by the cooling control unit 204. Figure 3 In the example shown, where the line represents a case where the degradation level of battery 2 is higher than a predetermined reference level, it is assumed that the determination unit 202 determines a first charge amount A1, and the determination unit 202 also determines a second charge amount A2 that is higher than the first charge amount A1. In this case, when the determination unit 202 determines the first charge amount A1, the cooling control unit 204 determines that the cooling start temperature of the single cell B1 is higher than the cooling start temperature of the single cell B2 when the determination unit 202 determines the second charge amount A2.

[0054] When the degradation level of battery 2 is relatively high, its rechargeable capacity is low. Therefore, when the degradation level of battery 2 is relatively high, the cooling control unit 204 determines a higher cooling start single-cell temperature in the same manner as when the charge level of battery 2 is relatively low. Figure 3 In the example, when the charge amount determined by the determining unit 202 is equal to or greater than a predetermined value E, and the determining unit 202 determines a degradation level equal to a reference level (corresponding to a first degradation level), the cooling control unit 204 determines that the cooling start single-cell temperature B3' is lower than the cooling start single-cell temperature B3 when the charge amount is equal to or greater than the same predetermined value E, and the determining unit 202 determines a degradation level higher than a reference level (corresponding to a second degradation level). For example, the predetermined value E represents the temperature corresponding to... Figure 3 The value of the charge corresponding to the intersection of multiple lines representing different degrees of degradation.

[0055] [Cooling begins using secondary refrigerant]

[0056] When the temperature inside a single cell of battery 2, acquired by the acquisition unit 201, is higher than the determined cooling start temperature of the single cell, the cooling control unit 204 operates the electric compressor 11 to begin cooling the cooling water using secondary refrigerant. In the example of this specification, when the highest temperature among the temperatures inside the single cells acquired by the acquisition unit 201 is higher than the cooling start temperature of the single cell, the cooling control unit 204 begins cooling the cooling water using secondary refrigerant.

[0057] Figure 4 This illustrates the relationship between the temperature within a single cell of battery 2 and the operation of the cooling control unit 204. Assuming... Figure 4The temperature shown is the highest temperature among the individual cell temperatures of battery 2 measured by multiple individual cell temperature sensors 21.

[0058] When the temperature inside a single cell acquired by the acquisition unit 201 is equal to or lower than the temperature before the shutdown, the cooling control unit 204 does not begin cooling the cooling water using secondary refrigerant. When the temperature inside a single cell is higher than the temperature before the shutdown, and when the temperature inside a single cell is equal to or lower than the single cell temperature at which cooling begins, the cooling control unit 204 operates in the minimum cooling mode. In the minimum cooling mode, the cooling control unit 204 does not perform cooling of the cooling water using secondary refrigerant. In this minimum cooling mode, the cooling water is cooled by the radiator 3.

[0059] When the temperature inside the single cell is higher than the cooling start temperature of the single cell, and when the temperature inside the single cell is lower than the transition temperature, the cooling control unit 204 operates in normal cooling mode. When the temperature inside the single cell is equal to or higher than the transition temperature, the cooling control unit 204 operates in maximum cooling mode. In both normal and maximum cooling modes, the cooling control unit 204 uses secondary refrigerant to cool the coolant. In normal cooling mode, while the cooling control unit 204 uses secondary refrigerant to cool the coolant, the air conditioning control unit 205 (described later) exchanges heat between the air inside the vehicle and the secondary refrigerant. On the other hand, in maximum cooling mode, the cooling control unit 204 prioritizes using secondary refrigerant to cool the coolant, and the air conditioning control unit 205 restricts heat exchange between the air inside the vehicle and the secondary refrigerant. In both normal and maximum cooling modes, the coolant is cooled by the radiator 3 in the same manner as in minimum cooling mode.

[0060] Although Figure 4 The example does not show the temperature of the cooling water, but the cooling control unit 204 operates in normal cooling mode when the temperature inside the single cell is higher than the cooling start single cell temperature, when the temperature inside the single cell is lower than the cooling start single cell temperature, and when the first water temperature measured by the water temperature sensor 8 is higher than the reference water temperature. The reference temperature is, for example, a temperature that is determined by those skilled in the art to be suitable for cooling the battery 2.

[0061] On the other hand, when the temperature inside a single battery is higher than the temperature before the shutdown but equal to or lower than the cooling temperature of the single battery, the cooling control unit 204 operates in the minimum cooling mode. When the temperature inside a single battery is higher than the cooling start temperature of the single battery, but the first water temperature measured by the water temperature sensor 8 is equal to or lower than the reference water temperature, the cooling control unit 204 operates in the minimum cooling mode.

[0062] The cooling control unit 204 uses secondary refrigerant to cool the cooling water, so that the temperature inside the single cell does not exceed a predetermined upper limit temperature during the period before the battery 2 is depleted. Figure 5An example is shown where a secondary refrigerant is used to cool the cooling water via the cooling control unit 204. Figure 5 The vertical axis represents the temperature inside the single cell and the charge level of cell 2. Figure 5 The horizontal axis represents time.

[0063] exist Figure 5 In the example, the time it takes for the temperature inside a single cell to exceed the initial single-cell temperature before cooling begins is represented as 0 seconds. At this time, the cooling control unit 204 begins to cool the cooling water using secondary refrigerant. At this time, because the heat generated by battery 2 due to discharge is greater than the cooling capacity of the cooling control unit 204, the temperature inside the single cell ( Figure 5 The thicker line in the image increases over time. On the other hand, as... Figure 5 As shown, the charge of battery 2 decreases over time due to discharge.

[0064] Based on the charge amount determined by the determination unit 202, the cooling control unit 204 determines the time when the battery 2 will be depleted. The cooling control unit 204 adjusts the cooling amount of the secondary refrigerant to the cooling water so that the temperature inside the single cell does not exceed the upper limit temperature before the battery 2 is depleted.

[0065] For example, through Figure 1 The refrigerant expansion valve 17 alternates between an open state and a closed state, and the cooling control unit 204 adjusts the amount of secondary refrigerant supplied to the refrigerator 7 and the cooling amount of the secondary refrigerant on the cooling water. The cooling control unit 204 determines the ratio of the time period during which the refrigerant expansion valve 17 is in the open state to the entire time period, so that... Figure 5 When the charge of battery 2 shown is zero, the temperature inside the single battery is below the upper limit temperature. The cooling control unit 204 controls the refrigerant expansion valve 17 to keep the refrigerant expansion valve 17 in the open state for a specified time. The cooling control unit 204 can adjust the cooling amount of the secondary refrigerant on the cooling water by adjusting the output power of the electric compressor 11.

[0066] [Cool the battery 2 before the vehicle stops]

[0067] If the temperature inside the single cell in battery 2 remains equal to or higher than the temperature before stopping for an extended period of time ( Figure 4 If the temperature inside the battery is not equal to or lower than the initial temperature of the battery, the battery 2 is at risk of deterioration. Therefore, the cooling control unit 204 cools the battery 2 to below the temperature before stopping before the vehicle 100 stops driving, either before or after the vehicle stops driving. At this time, even if the temperature inside the single cell is equal to or lower than the single cell temperature at which cooling begins, it is assumed that the cooling control unit 204 uses secondary refrigerant to cool the cooling water.

[0068] First, the cooling control unit 204 determines the estimated arrival time of the vehicle 100, which is equipped with the control device 1, to its destination. For example, if the operation receiving unit (not shown) receives an operation from the driver specifying a destination, the cooling control unit 204 determines the travel time required for the vehicle 100 to travel from its current position to the destination. The cooling control unit 204 determines the estimated arrival time based on the current time and the determined travel time.

[0069] The cooling control unit 204 uses secondary refrigerant to cool the cooling water, thereby reducing the temperature inside each cell of battery 2 to below the predetermined pre-stop temperature before the determined expected arrival time. For example, the cooling control unit 204 adjusts the amount of cooling water provided by the secondary refrigerant to reduce the temperature inside each cell of the battery to below the predetermined pre-stop temperature before the determined expected arrival time. Thus, the cooling control unit 204 can prevent the degradation of battery 2. The cooling control unit 204 is not limited to the example of reducing the temperature of battery 2 to below the pre-stop temperature before the expected arrival time; it can also cool battery 2 to the pre-stop temperature by continuing to use secondary refrigerant to cool battery 2 for a certain period of time after vehicle 100 has stopped at the destination parking lot.

[0070] [Intermittent operation of the vehicle's interior air conditioning]

[0071] The air conditioning control unit 205 uses secondary refrigerant to cool the air inside the vehicle. The air conditioning control unit 205 reduces the temperature inside the vehicle 100 by exchanging heat between the internal air in the evaporator 15 included in the refrigeration cycle and the secondary refrigerant.

[0072] When the temperature inside a single cell of battery 2 is higher than the transition temperature, the air conditioning control unit 205 prioritizes using secondary refrigerant to cool the cooling water, rather than using secondary refrigerant to lower the temperature inside the vehicle. More specifically, when the cooling control unit 204 is using secondary refrigerant to cool the cooling water, if the temperature obtained by the acquisition unit 201 is higher than the transition temperature, the air conditioning control unit 205 stops the heat exchange between the secondary refrigerant and the interior air for a stop period at predetermined time intervals. The stop period is shorter than the predetermined time interval. For example, the transition temperature is the upper limit of the temperature inside a single cell that allows the use of both cooling water and secondary refrigerant to cool battery 2 without restricting the supply of secondary refrigerant to the evaporator 15.

[0073] In the example in this specification, the air conditioning control unit 205 controls the refrigerant expansion valve 14 to close, thereby stopping the supply of secondary refrigerant to the evaporator 15 inside the vehicle and stopping the heat exchange between the secondary refrigerant and the interior air. Figure 6 An example of controlling the refrigerant expansion valve 14 via the air conditioning control unit 205 is shown. The vertical axis represents the open state (refrigerant expansion valve open) and the closed state (refrigerant expansion valve closed). Figure 6 In the example, the air conditioning control unit 205 stops the time period T every predetermined time period T. OFF Close the refrigerant expansion valve 14 to limit the supply of secondary refrigerant to the evaporator 15.

[0074] Even when the output of battery 2 is low, the temperature inside a single cell of battery 2 is higher than the transition temperature, battery 2 can still be cooled using secondary refrigerant without restricting the supply of secondary refrigerant to evaporator 15. Therefore, when the output of battery 2 detected by output detection unit 203 is equal to or lower than a reference value, air conditioning control unit 205 does not stop the heat exchange between secondary refrigerant and internal air. The reference value is the maximum output of battery 2 that allows cooling of battery 2 using cooling water and secondary refrigerant when the supply of secondary refrigerant to evaporator 15 is unrestricted.

[0075] [Switch cooling water circuit]

[0076] The switching control unit 206 controls the switching unit 5, which switches the flow path of the cooling water. When the value obtained by subtracting the second water temperature from the first water temperature obtained from the acquisition unit 201 is equal to or greater than the first reference value, the switching control unit 206 controls the switching unit 5 to make the cooling water circulate in the first cooling water circuit that passes through the radiator 3. When the value obtained by subtracting the second water temperature from the first water temperature obtained from the acquisition unit 201 is less than the second reference value, the switching control unit 206 controls the switching unit 5 to make the cooling water circulate in the second cooling water circuit that does not pass through the radiator 3.

[0077] Figure 7 and Figure 8 An example is shown of controlling the switching unit 5 using the switching control unit 206. Figure 7 This shows the state of cooling water circulating in the first cooling water loop through radiator 3. Figure 8 This shows the state of cooling water circulating in a second cooling water circuit that does not pass through radiator 3.

[0078] like Figure 7 As shown, in the first cooling water circuit, the cooling water passing through battery 2 passes through water temperature sensor 8, radiator 3, water temperature sensor 9, switching unit 5, pump 6, and cooler 7, before returning to battery 2. At this time, the cooling water does not pass through... Figure 7 The bypass is indicated by the dashed line.

[0079] like Figure 8 As shown, in the second cooling water circuit, the cooling water passing through battery 2 passes through water temperature sensor 8, switching unit 5, pump 6, and cooler 7, and returns to battery 2. At this time, the cooling water does not pass through radiator 3 and water temperature sensor 9.

[0080] The switching control unit 206 calculates a value obtained by subtracting the second water temperature measured by the water temperature sensor 9 from the first water temperature measured by the water temperature sensor 8. This value represents the amount of cooling water temperature reduction caused by heat exchange between the outside air and the cooling water in the radiator 3. When this value is equal to or greater than a first reference value, the switching control unit 206 determines that the cooling water is being cooled by the radiator 3. The first reference value is, for example, a value greater than 0. At this time, the switching control unit 206 controls the switching unit 5 to make the cooling water... Figure 7 It circulates in the first cooling water circuit shown.

[0081] When the value obtained by subtracting the second water temperature from the first water temperature obtained from the acquisition unit 201 is less than the second reference value, the switching control unit 206 determines that the cooling water is not being cooled by the radiator 3. At this time, the switching control unit 206 controls the switching unit 5 to circulate the cooling water in a second cooling water loop that does not pass through the radiator 3. The second reference value is, for example, a value less than 0. In this way, when the outside air is at a relatively high temperature, the switching control unit 206 can prevent the temperature of the cooling water from rising due to heat exchange with the outside air in the radiator 3.

[0082] [The process of cooling water using secondary refrigerant]

[0083] Figure 9 This is a flowchart illustrating the process by which the control device 1 uses secondary refrigerant to cool the cooling water. This process begins when the vehicle 100 is in motion. First, the acquisition unit 201 acquires the temperature inside each individual cell of the battery 2 (S101). The determination unit 202 determines the charge level of the battery 2 (S102). The cooling control unit 204 determines the starting temperature of the individual cell for cooling based on the charge level determined by the determination unit 202 (S103).

[0084] The cooling control unit 204 determines whether the temperature inside the single cell acquired by the acquisition unit 201 is higher than the cooling start single cell temperature (S104). When the temperature inside the single cell acquired by the acquisition unit 201 is higher than the cooling start single cell temperature ("Yes" in S104), the cooling control unit 204 operates the electric compressor 11 to start cooling the cooling water using secondary refrigerant (S105) and ends the process. When the temperature inside the single cell acquired by the acquisition unit 201 in S104 is equal to or lower than the cooling start single cell temperature ("No" in S104), the cooling control unit 204 returns to the process in S101 and does not start cooling the cooling water using secondary refrigerant.

[0085] [Effects of Control Device 1 in this Embodiment]

[0086] When the charge level of battery 2 is low, the cooling control unit 204 determines the high temperature as the starting temperature for cooling battery 2. In this way, the cooling control unit 204 delays the time required to start cooling the cooling water using secondary refrigerant, thereby reducing the power required to cool battery 2.

[0087] On the other hand, when the charge level of battery 2 is high, the temperature inside each cell of battery 2 may rise due to prolonged operation. Therefore, the cooling control unit 204 determines a low temperature as the starting temperature for cooling each cell of battery 2. In this way, the cooling control unit 204 can prevent the temperature inside each cell of battery 2 from rising by starting to cool battery 2 with secondary refrigerant as early as possible.

[0088] In this embodiment, the cooling control unit 204 directly controls the adjustment of the output power of the electric compressor 11, and also directly controls the switching between the open and closed states of the refrigerant expansion valve 17. The cooling control unit 204 can also control the adjustment of the output power of the electric compressor 11 via another air conditioning control device (not shown). The cooling control unit 204 instructs this other air conditioning control device to adjust the output power of the electric compressor 11, and this air conditioning control device can control the adjustment of the output power of the electric compressor 11. Similarly, the cooling control unit 204 can also control the switching between the open and closed states of the refrigerant expansion valve 17 via another air conditioning control device. The cooling control unit 204 instructs this other air conditioning control device to control the switching between the open and closed states of the refrigerant expansion valve 17, and this air conditioning control device can control the switching between the open and closed states of the refrigerant expansion valve 17.

[0089] In this embodiment, the air conditioning control unit 205 directly controls the switching between the open and closed states of the refrigerant expansion valve 14. The air conditioning control unit 205 can also control the switching between the open and closed states of the refrigerant expansion valve 17 via another air conditioning control device. The air conditioning control unit 205 instructs the other air conditioning control device to control the switching between the open and closed states of the refrigerant expansion valve 17, and the air conditioning control device can also control the switching between the open and closed states of the refrigerant expansion valve 14.

[0090] This disclosure has been described based on exemplary embodiments. The technical scope of this disclosure is not limited to the scope described in the above embodiments, and various changes and modifications can be made within the scope of this invention. For example, all or part of the apparatus may be configured with any functionally or physically distributed or integrated units. Furthermore, new exemplary embodiments resulting from any combination of these units are also included in the exemplary embodiments. Moreover, the effects of the new exemplary embodiments resulting from the combination also have the effects of the original exemplary embodiments.

[0091] Explanation of reference numerals in the attached figures

[0092] 1 Control device

[0093] 2 batteries

[0094] 3 Radiators

[0095] 4 radiator fans

[0096] 5 Switching Unit

[0097] 6 pumps

[0098] 7. Refrigerator

[0099] 8 water temperature sensors

[0100] 9 Water Temperature Sensors

[0101] 11 Electric Compressor

[0102] 12 Condenser

[0103] 13 Condenser Fan

[0104] 14 Refrigerant expansion valve

[0105] 15 Evaporator

[0106] 16. Blower Fan

[0107] 17 Refrigerant expansion valve

[0108] 21 Single-cell temperature sensor

[0109] 22 Voltage Sensor

[0110] 100 vehicles

[0111] 101 Storage Department

[0112] 102 Control Department

[0113] 201 Acquisition Department

[0114] 202 Determination Department

[0115] 203 Output Detection Department

[0116] 204 Cooling Control Department

[0117] 205 Air Conditioning Control Department

[0118] 206 Switching Control Unit.

Claims

1. A control device for controlling an electric compressor included in a refrigeration cycle, the refrigeration cycle being used to circulate and cool a secondary refrigerant that exchanges heat with cooling water in a battery, the control device comprising: The acquisition unit acquires the temperature of each individual cell in the battery. The determining unit determines the amount of charge on the battery; as well as The cooling control unit determines the cooling start temperature of the single cell based on the charge amount determined by the determining unit, and operates the electric compressor to begin cooling the cooling water using the secondary refrigerant if the temperature obtained by the acquiring unit is higher than the determined cooling start temperature of the single cell. The lower the charge level of the battery, the higher the cooling start temperature of the single battery determined by the cooling control unit. When the determining unit determines the first charge level, the cooling control unit determines a higher cooling start temperature of the single battery than when the determining unit determines a second charge level that is higher than the first charge level.

2. The control device according to claim 1, wherein, The cooling control unit uses the secondary refrigerant to cool the cooling water, ensuring that the temperature inside the single battery does not exceed a predetermined upper limit temperature during the period before the battery is depleted.

3. The control device according to claim 2, wherein, The cooling control unit uses a refrigerator that exchanges heat between the cooling water and the secondary refrigerant to cool the cooling water, and alternates between an open state and a closed state of the refrigerant expansion valve to control the amount of cooling water using the secondary refrigerant, which is supplied to the refrigerator through the refrigerant expansion valve. It also determines the ratio of the time the refrigerant expansion valve is in the open state to the entire time period, such that the temperature inside the single cell is below the upper limit temperature during the period before the cell is depleted.

4. The control device according to any one of claims 1 to 3, further comprising an air conditioning control unit that reduces the internal temperature of the evaporator included in the refrigeration cycle by heat exchange between the secondary refrigerant and the internal air, and, when the cooling control unit is cooling the cooling water using the secondary refrigerant, stops the heat exchange between the secondary refrigerant and the internal air for a stop time period shorter than the predetermined time period at predetermined time intervals, provided that the temperature obtained by the acquisition unit is higher than the transition temperature. The transition temperature is the upper limit of the temperature within the single cell that allows the battery to be cooled using the cooling water and the secondary refrigerant without limiting the supply of the secondary refrigerant to the evaporator.

5. The control device according to claim 4 further includes an output detection unit that detects the output of the battery, wherein, When the output of the battery is equal to or less than the reference value, the air conditioning control unit does not stop the heat exchange between the secondary refrigerant and the internal air.

6. The control device according to any one of claims 1 to 3, wherein, The determining unit determines the degree of degradation of the battery, and When the charge amount determined by the determining unit is equal to or greater than a predetermined value, and when the determining unit determines a first degree of degradation, the cooling control unit determines a lower cooling start single-cell temperature than when the determining unit determines a second degree of degradation that is higher than the first degree of degradation.

7. The control device according to any one of claims 1 to 3, wherein, The acquisition unit acquires the first water temperature of the cooling water measured by the first water temperature sensor and the second water temperature of the cooling water measured by the second water temperature sensor. The first water temperature sensor is located upstream of the radiator in the cooling water circuit, which facilitates heat exchange between the cooling water and the outside air. The cooling water circuit is used for heat exchange between the battery and the cooling water. The second water temperature sensor is located downstream of the radiator. The control device further includes a switching control unit. When the value obtained by subtracting the second water temperature from the first water temperature is equal to or greater than a first reference value, the switching control unit controls the switching unit for switching the flow path of the cooling water so that the cooling water circulates in a first cooling water circuit through the radiator. When the value obtained by subtracting the second water temperature from the first water temperature is less than a second reference value smaller than the first reference value, the switching control unit controls the switching unit so that the cooling water circulates in a second cooling water circuit that does not pass through the radiator.

8. The control device according to any one of claims 1 to 3, wherein, The cooling control unit determines the estimated arrival time of the vehicle equipped with the control device when it reaches its destination, and uses the secondary refrigerant to cool the cooling water so that the temperature inside the individual cells in the battery is reduced to below a predetermined pre-stop temperature before the estimated arrival time.

9. The control device according to any one of claims 1 to 3, wherein, The acquisition unit acquires the temperature of multiple individual cells in the battery, and When the highest temperature among the temperatures within the single cell obtained by the acquisition unit is higher than the single cell temperature at which cooling begins, the cooling control unit begins to cool the cooling water using the secondary refrigerant.

10. A control method for controlling an electric compressor included in a refrigeration cycle, the refrigeration cycle being used to circulate secondary refrigerant to cool cooling water that exchanges heat with a battery, the control method comprising the steps of: Obtain the temperature of a single cell in the battery; Determine the charge level of the battery; The starting temperature of a single cell is determined based on the amount of charge. as well as When the obtained temperature is higher than the determined cooling start temperature of the single cell, the cooling water is started to be cooled using the secondary refrigerant by operating the electric compressor, wherein... In the step of determining the cooling start single cell temperature, the lower the charge level of the battery, the higher the cooling start single cell temperature is determined. When a first charge level is determined, a higher cooling start single cell temperature is determined than when a second charge level is determined, where the second charge level is higher than the first charge level.

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