Method and device for controlling cooling of battery of electric vehicle

Abstract

This method for controlling cooling of a battery of an electric vehicle, which is rapidly charged by a charger provided in a charging spot, comprises: acquiring charger information relating to the charger; acquiring battery state information relating to the state of the battery; and, on the basis of the charger information and the battery state information, predicting whether or not the temperature of the battery reaches a predetermined upper limit threshold within a predetermined rapid charging time.

Description

Cooling control method and cooling control device for battery of electric vehicle

[0001] The present invention relates to a cooling control method and a cooling control device for a battery of an electric vehicle.

[0002] Patent Document 1 discloses a cooling control system for a battery of an electric vehicle. This cooling control system determines whether there are signs of battery charging while the electric vehicle is running and / or stopped. If it determines that there are signs of charging, it determines whether the battery needs to be cooled. If it determines that battery cooling is necessary, it cools the battery while the vehicle is running to a predetermined temperature. The determination of whether battery cooling is necessary is based on the real-time battery temperature, the increase in battery temperature due to charging, and a predetermined battery allowable temperature upper limit. Patent Document 1 also describes cooling the battery by chiller cooling even while the vehicle is stopped and charging.

[0003] Japanese Patent Application Laid-Open No. 2020-039226

[0004] The rate at which the battery temperature rises varies depending on conditions such as the charging time and charging method. Cooling the battery during fast charging without considering this rate of temperature rise may result in a further decrease in the charge amount. In other words, unconditional cooling during fast charging may result in excessive cooling, resulting in a corresponding loss of power. On the other hand, if cooling is initiated based on the real-time battery temperature during fast charging, the battery's acceptable power will be limited according to the battery temperature, resulting in a corresponding decrease in the charge amount. The cooling control system disclosed in Patent Document 1 does not take this into consideration.

[0005] In one aspect, the present invention has been made in consideration of the above circumstances, and its purpose is to provide a battery cooling control method and cooling control device that further improves the charge amount during rapid charging while the vehicle is stopped.

[0006] In order to solve the above-mentioned problems, a battery cooling control method according to one aspect of the present invention is a method for controlling cooling of a battery of an electric vehicle that is rapid charged by a charger provided at a charging spot, and includes the following: - Acquiring charger information related to the charger - Acquiring battery state information related to the state of the battery - Predicting whether the temperature of the battery will reach a predetermined upper threshold within a predetermined rapid charging time based on the charger information and the battery state information - Controlling the timing of starting cooling of the battery within the predetermined rapid charging time based on the prediction of whether the temperature of the battery will reach the predetermined upper threshold.

[0007] According to the present invention, the amount of charge can be further improved in rapid charging while the vehicle is stopped.

[0008] A block diagram showing the configuration of a control system for a battery of a vehicle according to an embodiment. A timing chart showing the behavior of values ​​during normal rapid charging. A timing chart showing the behavior of values ​​when an operation signal is transmitted. A timing chart showing the behavior of values ​​when an investigation signal is transmitted. A flowchart of a cooling control method according to an embodiment.

[0009] An embodiment according to one aspect of the present invention (hereinafter also referred to as "the present embodiment") will be described below with reference to the drawings. However, the present embodiment described below is merely an example of the present invention in all respects. Needless to say, various improvements and modifications can be made without departing from the scope of the present invention. In other words, when implementing the present invention, specific configurations according to the embodiment may be appropriately adopted. Note that, although data appearing in the present embodiment are described in natural language, more specifically, they are specified using pseudo-language, commands, parameters, machine language, etc. that can be recognized by a computer.

[0010] 1. Overall Configuration FIG. 1 is a block diagram showing the configuration of a control system for a battery 6 mounted on a vehicle 1 according to this embodiment. The vehicle 1 is an electric vehicle. The vehicle 1 includes a navigation system 2 (hereinafter also referred to as the "NV system 2"), a battery controller 3, an EV controller 4, a charge controller 5, a battery 6, and a cooling system 7. The battery 6 is supplied with power as needed from a stationary charger 8 installed at a predetermined charging spot. The charger 8 includes a normal charge port and a rapid charge port (not shown). The cooling control method for the battery 6 according to this embodiment is applied when the battery 6 is rapidly charged via the rapid charge port within a rapid charge time. The rapid charge time is a predetermined duration of charging to achieve a large capacity charge in a short period of time compared to normal charging, and is not particularly limited, but may be, for example, 30 minutes.

[0011] [NV System] The NV system 2 may be configured as a car navigation system including a central processing unit (CPU), random access memory (RAM), read-only memory (ROM), a nonvolatile rewritable storage device, an input / output interface, a communication device, and the like. The ROM or storage device stores programs for the NV system 2, as well as data such as map information and road gradients. The communication device receives positioning signals from a global navigation satellite system (GNSS) and road traffic information from a road traffic information and communication system (VICS (registered trademark)). For example, when a passenger of the vehicle 1 sets a destination, the NV system 2 can generate a route to the destination based on the current position based on map information and positioning signals and present the route to the passenger, and also present road traffic information for the route to the passenger. Information is presented, for example, on a display screen (not shown) or via audio output from a speaker (not shown). The RAM is used as appropriate for CPU calculations.

[0012] The road traffic information according to this embodiment includes information about charging spots that can be used by the vehicle 1. The charging spot information includes location information about the charging spot, and may also include charger information about the charger 8 installed at the charging spot. The charger information includes output information about the output of the charger 8. The output information is expressed, for example, in the form of the maximum wattage that the charger 8 can output, or the maximum amperage and voltage that the charger 8 can output.

[0013] The NV system 2 may be configured to suggest charging and chargers 8 to the occupant while the vehicle 1 is traveling. The NV system 2 may prompt the occupant to charge the battery 6 and search for charging spots that allow rapid charging near the current location of the vehicle 1, based on at least one of the current cruising range of the vehicle 1, the current SOC of the battery 6, and the distance to the destination, for example. The NV system 2 may then present the search results for charging spots and output information of available chargers 8 to the occupant, allowing the occupant to select the next charger 8 to visit.

[0014] The battery controller 3, the EV controller 4, and the charge controller 5 are each configured with a microcomputer including a CPU, RAM, ROM, and an input / output interface. The battery controller 3, the EV controller 4, and the charge controller 5 are each controlled by the CPU executing a program stored in the ROM. These controllers are connected to each other so that data can be communicated with each other. At least two of these controllers may be configured with the same microcomputer. At least one of these controllers may be configured with multiple microcomputers.

[0015] [Battery Controller] The battery controller 3 is configured to acquire detection signals from the temperature sensor 31, voltage sensor 32, and current sensor 33 provided in the vehicle 1 and monitor the state of the battery 6. The temperature sensor 31, voltage sensor 32, and current sensor 33 are not particularly limited as long as they detect the temperature T, internal current I, and potential difference V of the battery 6, respectively, and output electrical signals corresponding to the detected values. The method for estimating the SOC is not particularly limited, and for example, the SOC can be estimated using a known method based on the acquired temperature T, internal current I, and potential difference V. The battery controller 3 transmits the SOC and temperature of the battery 6 to the EV controller 4 in response to a request from the EV controller 4. During rapid charging, the battery controller 3 determines the outputtable power and acceptable power of the battery 6 from the detection signals of the above sensors and transmits the determined power as an allowable charge / discharge signal to the EV controller 4 as needed. Typically, the acceptable power during rapid charging is determined to be reduced depending on the current temperature and SOC of the battery 6.

[0016] [EV Controller] The EV controller 4 is configured to control charging of the battery 6 and to control the timing at which the cooling system 7 starts cooling the battery 6. In other words, the EV controller 4 is an example of a cooling control device of the present invention. The CPU of the EV controller 4 reads and executes the above programs, thereby virtually functioning as a first acquisition unit 41, a second acquisition unit 42, a prediction unit 43, and a control unit 44.

[0017] When the first acquisition unit 41 detects a sign of charging, it acquires output information of the charger 8 from the NV system 2. The sign of charging is detected, for example, when an occupant specifies a specific charger 8 via the NV system 2 while the vehicle 1 is traveling. In addition, the first acquisition unit 41 may acquire a predetermined quick charging time from information such as the specifications of the charger 8.

[0018] While the vehicle 1 is traveling, the second acquisition unit 42 transmits the output power required of the battery 6 to the battery controller 3 as needed, based on operations by the driver of the vehicle 1, etc.

[0019] Furthermore, when the second acquisition unit 42 detects the charging warning, it acquires, as battery state information, c0, which is the state of charge (SOC) of the battery 6 at the rapid charging start time, and temperature T0 (SOC information and temperature information) from the battery controller 3. c0 is typically a value equal to or less than the SOC threshold at which rapid charging is required. The rapid charging start time strictly refers not only to the time when power supply from the charger 8 to the battery 6 starts, but also to the period immediately before or immediately after the rapid charging start. The period immediately before the rapid charging start refers to a period before the rapid charging start, during which the state of the battery 6 at that time can be considered to be the same as the state of the battery 6 at the time when rapid charging starts later (i.e., changes in the state of the battery 6 due to time can be ignored). The period immediately after the rapid charging stop refers to a period after power supply from the charger 8 to the battery 6 starts, during which the state of the battery 6 at that time can be considered to be the same as the state of the battery 6 at the time when rapid charging starts (i.e., changes in the state of the battery 6 due to time can be ignored). Hereinafter, the time when quick charging starts is designated as t0.

[0020] The prediction unit 43 creates a quick charge plan when quick charge starts. The quick charge plan is created based on at least one of the output information, quick charge time, the SOC (c0) and temperature T0 of the battery 6, a cooling threshold T1, the current cruising range, and electricity efficiency, and includes an SOC (c1) that is expected to be achieved by quick charge. Here, the cooling threshold T1 is a predetermined upper temperature threshold of the battery 6 at which cooling by the cooling system 7 is to start.

[0021] FIG. 2 is a timing chart showing an example of the behavior of vehicle speed [km / h], charging output [kW], battery 6 temperature [°C], SOC [%], and cooling energy [kW] during normal quick charging at a predetermined ambient temperature. Because quick charging is performed while the vehicle 1 is stopped, the vehicle speed remains zero throughout the quick charging period. The charging output is the power supplied from the charger 8 to the battery 6 and is maintained approximately constant at the maximum value W0 that the battery 6 can accept from time t0 to t2. As the SOC increases, the charging output decreases at a substantially constant rate a1 from time t2 to t3. When the temperature of the battery 6 reaches an upper threshold value T2 at time t3, the charging output decreases at a larger rate a2. Temperature T2 is the upper temperature limit of the battery 6, which is predetermined to limit the charging output. After the charging output reaches W2 at time t4, it remains approximately constant thereafter. Rates a1 and a2 are predetermined values ​​based on the temperature and SOC, respectively. Assuming that the internal resistance R and internal current I of the battery 6 are constant, the temperature of the battery 6 rises at a generally constant gradient from time t0. If the temperature of the battery 6 reaches the cooling threshold T1 at time t1, the cooling system 7 starts cooling at time t1, and the temperature of the battery 6 rises at a gentler gradient from time t1 onward. When the temperature of the battery 6 subsequently reaches the upper threshold T2 at time t3, the charging output is limited to W2, thereby reducing the internal current I. This suppresses self-heating of the battery 6 so that the temperature does not exceed the upper threshold T2. The SOC rises at a generally constant gradient from time t0 to t2. The rate of increase in the SOC slows down after t2 in accordance with the rate at which the charging output is limited, and becomes gentler after time t4. The cooling energy represents the capacity of the cooling system 7, described below, to remove heat from the battery 6. In this embodiment, the cooling energy is set to a constant value q1, taking into account the cooling capacity required when the vehicle repeatedly travels and charges.

[0022] In accordance with the creation of the rapid charge plan, the prediction unit 43 predicts whether the temperature of the battery 6 will reach the upper limit threshold T2 within the rapid charge time. This prediction can be made based on the operation shown in the timing chart of Fig. 2 , for example, using a regression equation in which the output information, the SOC (c0) of the battery 6 at the start of rapid charge (t0), and the temperature T are explanatory variables, and the maximum temperature of the battery 6 is the objective variable. In the example of the timing chart of Fig. 2 , T2 is the maximum temperature. Coefficients that define the regression equation are identified in advance based on a large amount of experimental data or simulations, and stored in a memory area (memory device) of the EV controller 4, etc.

[0023] When the prediction unit 43 predicts that the temperature of the battery 6 will reach the upper threshold T2, the control unit 44 generates an operation signal or an adjustment signal and transmits it to the cooling system 7. The operation signal is a signal that requests the cooling system 7 to immediately start cooling when the prediction unit 43 predicts that the temperature of the battery 6 will reach the upper threshold T2. When the operation signal is transmitted, the cooling system 7 operates essentially at the same time as the start of fast charging. On the other hand, the adjustment signal is a signal that requests the cooling system 7 to start cooling at a predetermined timing. The adjustment signal can include, for example, a request to reset the cooling threshold T1 to the cooling threshold T3. The cooling threshold T3 is a temperature lower than the cooling threshold T1. In other words, by lowering the temperature threshold for starting cooling of the battery 6, the timing to start cooling can be advanced.

[0024] FIG. 3A is an example of a timing chart when an operation signal is transmitted under the same conditions as those in FIG. 2 , and FIG. 3B is an example of a timing chart when an adjustment signal is transmitted under the same conditions as those in FIG. 2 . The timing chart (dashed line) in FIG. 2 is superimposed on each of FIGS. 3A and 3B . However, for ease of explanation, these timing charts are appropriately simplified, such as by approximating curves with straight lines. Furthermore, times t2 to t5 do not necessarily need to strictly coincide in each timing chart. As shown in FIG. 3A , when an operation signal is transmitted, cooling by the cooling system 7 begins at time t0. Therefore, the temperature of the battery 6 rises at a gentler rate from the start of rapid charging compared to the case of FIG. 2 . Note that, because power is consumed for cooling from time t0 to t1, the rate of increase in SOC is smaller compared to the case of FIG. 2 . However, the resulting decrease in the rate of increase in SOC is minimal overall. At time t2, as in Fig. 2 , as the SOC increases, the charging output begins to decrease at a generally constant rate a1, but unless the temperature of battery 6 reaches the upper threshold T2, rate a1 is maintained until time t5. Therefore, from time t2 to t5, the SOC increases at a steeper slope than in Fig. 2 . After time t5, the charging output decreases to W2. Therefore, after time t5, the SOC increases at a slope generally similar to that in Fig. 2 .

[0025] Furthermore, as shown in FIG. 3B , when an adjustment signal is transmitted, cooling by the cooling system 7 begins at time t10 when the temperature of the battery 6 reaches T3. Time t10 is earlier than time t1. Therefore, the temperature of the battery 6 increases at a gentler rate after time t10 compared to the case of FIG. 2 . At time t2, as in FIG. 2 , the charging output begins to decrease at a generally constant rate a1 as the SOC increases. However, if the temperature of the battery 6 does not reach the upper threshold T2 at time t3, the rate a1 is maintained until time t5. Therefore, from time t2 to t5, the SOC increases at a steeper rate than in the case of FIG. 2 . After time t5, the charging output decreases to W2. Therefore, after time t5, the SOC increases at a rate generally similar to that in the case of FIG. 2 . Note that, assuming temperatures T0 and c0 are the same, the temperature of the battery 6 reaches the upper threshold T2 more quickly when cooling is started at time t10 than when cooling is started at time t0. Therefore, the final SOC is greater in the former case than in the latter case.

[0026] As described above, by transmitting the operation signal or adjustment signal to the cooling system 7, the decrease in charging efficiency of the battery 6 during rapid charging is more gradual, thereby reducing the amount of power P1 that is limited in acceptance due to the decrease in charging efficiency throughout the rapid charging period. However, to make the final state of charge (SOC) c2 greater than the original state of charge c1, the amount of power consumed by operating the cooling system 7 needs to be less than the amount of power P1. Therefore, in addition to the above prediction, the prediction unit 43 performs at least one of the following: calculating an increase P2 in the amount of power required for cooling if cooling of the battery 6 were to be started immediately; and calculating an increase P3 in the amount of power required for cooling by setting the cooling threshold to the cooling threshold T3. Hereinafter, the increases P2 and P3 will be referred to as the "amount of power P2" and the "amount of power P3," respectively.

[0027] The amount of electric power P1 corresponds to the area of ​​the shaded portion H1 in the timing charts of FIGS. 3A and 3B. Therefore, if the charging output at time t3 is W1, the amount of electric power P1 can be calculated by (t5-t4)×(W1-W2) / 2. The amount of electric power P2 corresponds to the amount of electric power output from the battery 6 to achieve the cooling energy of the shaded portion H2 in the timing chart of FIG. 3A, and can be calculated by b×q1×(t1-t0). Here, b is a constant for converting the cooling energy into the output power of the battery 6, which is specified in advance and stored in a memory area (storage device) such as the EV controller 4. If P1>P2, it is predicted that the charge amount c2 achieved by rapid charging will exceed c1 even if cooling of the battery 6 is immediately started. In this case, the control unit 44 generates an operation signal and transmits it to the cooling system 7. On the other hand, if P2≧P1, it is predicted that the charge amount c2 will not exceed c1 even if the control unit 44 transmits the operation signal. In such a case, the prediction unit 43 further calculates the amount of power P3.

[0028] The amount of power P3 corresponds to the amount of power output by the battery 6 to achieve the cooling energy of the shaded portion H3 in the timing chart of FIG. 3B . The time t10 is determined according to the temperature T3, which is the cooling threshold. Therefore, if the temperature T3 is determined according to a predetermined algorithm based on the temperature T0, such as by setting the midpoint T3 between the temperature T0 and the cooling threshold T1 as the cooling threshold, the amount of power P3 can be calculated as b×q1×(t1−t10). On the other hand, if the temperature T3 is not specified in advance, the time t at which P1=P3 is achieved can be calculated backward based on the above formula. If the calculated time t satisfies t0<t<t1, the temperature T3 can also be determined by determining the time t10 between the time t and the time t1.

[0029] To summarize the above, if temperature T3 is predetermined and P1 > P3, or if P1 > P3 and t10 can be determined such that t0 < t10 < t1, resetting cooling threshold T1 to T3 predicts that charge amount c2 will exceed c1. In this case, control unit 44 transmits an adjustment signal to cooling system 7. The adjustment signal includes a request to reset cooling threshold T1 to T3. As a result, cooling of battery 6 begins at time t10.

[0030] Furthermore, if P2≧P1 and there is no t10 that satisfies t0<t10<t1, the control unit 44 generates neither the operation signal nor the adjustment signal, and operates the cooling system 7 when the battery temperature reaches T1. In other words, the control unit 44 executes the original cooling control.

[0031] In addition to the above cooling control, the control unit 44 generates an allowable charge signal in response to an allowable charge / discharge signal received from the battery controller 3 during rapid charging, and transmits the allowable charge signal to the charge controller 5. The allowable charge signal indicates the amount of charge that can currently be accepted by the battery 6. The charge controller 5 controls the charge output of the charger 8 based on the allowable charge signal.

[0032] [Charge Controller] The charge controller 5 is communicatively connected to the charger 8 and configured to control the charge output of the charger 8. The charge controller 5 compares the allowable charge signal received from the EV controller 4 with the output capacity of the charger 8, generates a request charge signal, and transmits it to the charger 8. The request charge signal indicates the power that the charger 8 should currently output to the battery 6.

[0033] [Charger] The charger 8 supplies power to the battery 6 in accordance with the request charging signal when the quick charging port and the battery 6 are properly connected.

[0034] [Cooling System] The cooling system 7 is configured with a refrigerant circuit that can circulate a refrigerant that exchanges heat with the battery 6. In this embodiment, the refrigerant circuit is configured to include a chiller (not shown) through which the refrigerant circulates, and the battery 6 is cooled by heat exchange with the refrigerant circulating through the chiller. The chiller is also connected to, for example, an air conditioning circuit (not shown) that conditions the air in the vehicle 1, and performs heat exchange between another heat medium circulating through the air conditioning circuit and the refrigerant that has exchanged heat with the battery 6. In this way, the heat generated in the battery 6 is transferred to circuits that constitute other systems in the vehicle 1 and is used to reduce the power consumption of air conditioning.

[0035] 2. Cooling Control Method Figure 4 is a flowchart showing the flow of the cooling control method according to this embodiment. The cooling control method executed by the EV controller 4 (cooling control device) will be described below with reference to Figures 2 to 4. The cooling control method shown in Figure 4 is initiated, for example, when the first acquisition unit 41 detects a sign of charging while the vehicle 1 is traveling.

[0036] First, the first acquisition unit 41 acquires output information of the charger 8 and location information of the charging spot where the charger 8 is installed from the NV system 2 (step S1).

[0037] Next, the first acquisition unit 41 acquires the current location information of the vehicle 1 from the NV system 2 (step S2).

[0038] Next, the first acquisition unit 41 compares the current location information of the vehicle 1 with the location information of the charging spot and determines whether the vehicle 1 has arrived at the charging spot (step S3). If the first acquisition unit 41 determines that the vehicle 1 has arrived at the charging spot (YES), step S4 is executed next. If the first acquisition unit 41 determines that the vehicle 1 has not arrived at the charging spot (NO), step S3 is executed again. Step S3 is equivalent to determining whether the current state of the battery 6 (specifically, the temperature and SOC) can be considered to be the same as the state of the battery 6 at the start of rapid charging by the charger 8. Therefore, in step S3, in addition to or instead of the above determination, the first acquisition unit 41 may determine whether the current state of the battery 6 can be considered to be the same as the state of the battery 6 at the start of rapid charging by the charger 8. In this case, the first acquisition unit 41 may determine, for example, based on the current location information of the vehicle 1, the location information of the charging spot, and the current output power of the battery 6, whether the current state of the battery 6 can be considered to be the same as the state of the battery 6 at the start of rapid charging by the charger 8.

[0039] In the following step S4, the second acquisition unit 42 acquires, as battery state information, the current SOC and temperature of the battery 6 from the battery controller 3. The SOC and temperature of the battery 6 acquired in step S4 are c0 and temperature T0 at time t0.

[0040] Next, the prediction unit 43 predicts whether the temperature of the battery 6 will reach the upper threshold T2 (maximum temperature T2) within the rapid charge time. Specifically, the prediction unit 43 predicts the maximum temperature that the battery 6 will reach during the rapid charge time when the battery 6 is charged by the charger 8 for a predetermined rapid charge time (step S5), and compares the maximum temperature with the upper threshold T2 (step S6). As described above, this prediction is performed based on a regression equation that uses the output information, the SOC (c0) of the battery 6, and the temperature T0 as explanatory variables and the maximum temperature of the battery 6 as a response variable. If the comparison in step S6 predicts that the temperature of the battery 6 will reach the upper threshold T2 (YES), step S7 is executed. On the other hand, if the prediction predicts that the temperature of the battery 6 will not reach the upper threshold T2 (NO), cooling is not necessary during the rapid charge time, and the cooling control by the control unit 44 is terminated.

[0041] In step S7, the prediction unit 43 calculates the amounts of power P1 and P2 using the method described above.

[0042] In step S8, the prediction unit 43 compares the calculated power amounts P1 and P2 to determine which is larger. If the prediction unit 43 determines that P2 is equal to or larger than P1 (YES), step S9 is executed. On the other hand, if the prediction unit 43 determines that P1 is larger than P2 (NO), step S12 is executed.

[0043] In step S9, the prediction unit 43 calculates P3 using the method described above, or calculates backward the time t at which P1=P3 based on the above equation.

[0044] In step S10, the prediction unit 43 determines whether P3 calculated in step S9 satisfies P1>P3, or whether the time t calculated back in step S9 satisfies t0<t<t1 (i.e., whether a time t10 that satisfies the condition t0<t10<t1 exists). If the prediction unit 43 determines that P1>P3 (YES) or that a time t10 that satisfies the above condition exists (YES), step S11 is then executed. If the prediction unit 43 determines that P3≧P1 (NO) or that a time t10 that satisfies the above condition does not exist (NO), it is predicted that the charge amount will not increase even if the timing of cooling is advanced, and therefore the cooling control according to this flow is terminated.

[0045] In step S11, the control unit 44 transmits an adjustment signal to the cooling system 7. As a result, the cooling threshold temperature for starting cooling of the battery 6 is reset to T3, and the operation of the cooling system 7 starts at time t10.

[0046] In step S12, the control unit 44 transmits an operation signal to the cooling system 7. As a result, the operation of the cooling system 7 starts at time t0.

[0047] 3. Features According to the cooling control method of the above embodiment, it is possible to suppress the limit on the power received by the battery during fast charging and further increase the charge amount without adding any new on-board equipment. Furthermore, the cooling control method of the above embodiment performs cooling control based on the magnitude relationship between the amounts of power P1 to P3, so it is possible to more reliably increase the charge amount.

[0048] 4. Modifications Although the embodiments of the present invention have been described above in detail, the above description is merely an example of the present invention in every respect. It goes without saying that various improvements or modifications can be made without departing from the scope of the present invention. For example, the following modifications are possible. Note that, in the following, the same reference numerals are used for components similar to those in the above embodiment, and descriptions of the same points as those in the above embodiment are omitted where appropriate. The following modifications can be combined as appropriate.

[0049] (1) The prediction of whether the temperature of the battery 6 will reach the upper limit threshold T2 may be made without using a regression equation for predicting the maximum temperature. The prediction may be made, for example, based on the temperature T0, the internal resistance R of the battery 6, the internal current I of the battery 6, and the heat capacity C of the battery 6. Specifically, R×I 2 The amount of heat generated by the battery 6 per unit time can be calculated by calculating R×I. 2 By dividing t0 by t1 / C, the amount of temperature rise dT per unit time of the battery 6 can be obtained. Based on this amount of temperature rise dT, the predicted time t1 at which the temperature of the battery 6 will reach T2 can be calculated. If (t1 - t0) is shorter than the predetermined fast charge time, it can be predicted that the temperature of the battery 6 will reach the upper limit threshold T2. The internal resistance R and heat capacity C of the battery 6 may be stored in advance in a memory area of ​​the EV controller 4 or the like. Information on the internal current I of the battery 6 may be obtained by calculation based on the charging output W0 and internal resistance R specified from the output information, or may be obtained from a signal detected by the current sensor 33 immediately after the start of fast charge.

[0050] (2) The output information does not have to be acquired by the NV system 2. That is, steps S1 to S3 in the cooling control method may be omitted. Also, the NV system 2 may be omitted. In this case, the output information may be acquired through wired or wireless data communication between the charge controller 5 and the charger 8. Alternatively, the output information may be acquired as the power received by the battery 6 when the charger 8 and the battery 6 are connected. The power received by the battery 6 may be determined based on at least one of the voltage detected by the voltage sensor 32 and the current detected by the current sensor 33. Alternatively, a portable information processing terminal carried by the occupant may have the functions of the NV system 2, and the portable information processing terminal may acquire the output information and transmit it to the EV controller 4.

[0051] (3) At least one of the voltage sensor 32 and the current sensor 33 may be omitted, and a known SOC sensor may be provided in addition to or instead of the voltage sensor 32 and the current sensor 33.

[0052] (4) Although the cooling system 7 is configured with a circuit including a chiller that exchanges heat with the battery 6, the configuration of the cooling system 7 can be changed as appropriate. For example, the battery 6 may be cooled by a fan in addition to or instead of the chiller.

[0053] (5) The cooling control method is not limited to that of the above embodiment. For example, the cooling threshold value of the temperature of the battery 6 may be reset from T1 to T0 without particularly distinguishing between the operation signal and the adjustment signal, thereby starting cooling immediately (at time t0). In addition, in the above embodiment, the amount of electric power P3 is calculated when the determination in step S8 is YES. However, the amounts of electric power P1 to P3 may be calculated in step S7, and the operation signal or the adjustment signal may be selected based on the magnitude relationship of the calculated amounts of electric power P1 to P3.

[0054] 1 Vehicle 2 Control device 3 Battery controller 4 EV controller (cooling control device)

Claims

1. A method for controlling the cooling of a battery of an electric vehicle that is rapid charged by a charger installed at a charging spot, comprising: acquiring charger information related to the charger; acquiring battery status information related to the status of the battery; predicting whether the temperature of the battery will reach a predetermined upper threshold within a predetermined rapid charging time based on the charger information and the battery status information; and controlling the timing of starting cooling of the battery within the predetermined rapid charging time based on the prediction of whether the temperature of the battery will reach the predetermined upper threshold.

2. A battery cooling control method according to claim 1, wherein the charger information includes output information relating to the output of the charger, and the battery state information includes temperature information relating to the temperature of the battery at the start time of rapid charging and SOC information relating to the state of charge of the battery at the start time of rapid charging.

3. The battery cooling control method according to claim 1 or 2, wherein the charger information is acquired using a navigation system mounted on the electric vehicle.

4. The battery cooling control method according to claim 1 or 2, wherein the charger information is acquired via communication with the charger.

5. The battery cooling control method according to claim 1 or 2, wherein the charger information is acquired from the power received by the battery when the charger is connected to the battery.

6. The battery cooling control method according to claim 2, wherein predicting whether the battery temperature will reach the predetermined upper threshold includes predicting the maximum temperature to be reached based on a regression equation that uses the output information, the temperature information, and the SOC information as explanatory variables and the maximum temperature to be reached by the battery within the predetermined fast charging time as a response variable, and further comprising specifying coefficients that define the regression equation in advance and storing them in a storage device mounted on the electric vehicle.

7. The battery cooling control method according to claim 2, further comprising obtaining, as the battery state information, information on the current flowing through the battery when the charger is connected to the battery; and predicting whether the temperature of the battery will reach the predetermined upper threshold value includes predicting the temperature that the battery will reach within the predetermined fast charging time based on the temperature information, the resistance of the battery, and the heat capacity of the battery.

8. A battery cooling control method according to claim 1 or 2, wherein controlling the timing to start cooling of the battery includes immediately starting cooling of the battery when it is predicted that the temperature of the battery will reach the predetermined upper threshold within the predetermined quick charging time, or lowering the battery temperature threshold at which cooling of the battery should start below the cooling threshold of the predetermined temperature at which cooling of the battery should start.

9. The battery cooling control method according to claim 1 or 2, further comprising: calculating an amount of power P1 that is limited to be accepted by the battery when the temperature of the battery reaches the predetermined upper threshold; and calculating an increase P2 in the amount of power required to cool the battery by immediately starting cooling of the battery when it is predicted that the temperature of the battery will reach the predetermined upper threshold, or calculating an increase P3 in the amount of power required to cool the battery by lowering the cooling threshold of the predetermined temperature at which cooling of the battery should be started when it is predicted that the temperature of the battery will reach the predetermined upper threshold, wherein controlling the timing to start cooling of the battery includes: immediately starting cooling of the battery when P1 > P2, or lowering the cooling threshold when P1 > P3.

10. A cooling control device for a battery of an electric vehicle that is rapid charged by a charger installed at a charging spot, comprising: a first acquisition unit that acquires charger information related to the charger; a second acquisition unit that acquires battery state information related to the state of the battery; a prediction unit that predicts whether the temperature of the battery will reach a predetermined upper threshold within a predetermined rapid charging time based on the charger information and the battery state information; and a control unit that controls the timing to start cooling the battery within the predetermined rapid charging time based on the prediction of whether the temperature of the battery will reach the predetermined upper threshold.

Images