Secondary battery system, control device for secondary battery system, control method, and program

Abstract

To equalize SOC of a cell module.SOLUTION: A control device 12 is configured to control a distribution circuit 11d of a plurality of cell modules 11. First processing is processing for determining supplied electric power to be supplied to a heating device 11b of the cell modules 11 such that electric power supplied to the heating device 11b of the cell module 11 is higher in the cell module 11 of the plurality of cell modules 11, the SOC or amount of charge of which is higher.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The disclosure herein relates to a secondary battery system, a control device for a secondary battery system, a control method, and a program. [Background technology]

[0002] International Publication No. 2016 / 021270 discloses an invention relating to a control device that controls the temperature of a module battery.

[0003] For each of the multiple temperature control units disclosed herein, the current temperature is obtained from the detection result of the temperature sensor, and whether the heater should be turned on or off to set the temperature to the target temperature is determined based on the current temperature and the temperature profile. Then, if it is determined that the heater should be turned on and the heater is selected, the heater is turned on, and if it is determined that the heater should be turned on but the heater is not selected or if it is determined that the heater should be turned off, the heater is turned off.

[0004] The control device updates the required power to be supplied to the heater based on the current temperature and the target temperature in order to set the temperature for each of the multiple temperature control units to the target temperature at each of multiple first update opportunities that arrive repeatedly with a relatively low frequency, and maintains the required power constant until the next arriving first update opportunity.The control device then determines the total required power as the sum of the required powers across the multiple heaters, and determines the total power consumption as the sum of the power consumed by each of the multiple heaters across the multiple heaters.In this case, the control device updates a heater selected from the multiple heaters at each of multiple second update opportunities that arrive repeatedly with a relatively high frequency so that the power difference between the total required power and the total power consumption falls within a reference range, and maintains the heater selected from the multiple heaters constant until the next arriving second update opportunity.

[0005] The publication claims that the total power consumption, calculated by adding up the power consumption of each of a plurality of heaters across the plurality of heaters, can be stabilized while the temperature of the module battery approaches a target temperature. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2016 / 021270 Summary of the Invention [Problem to be solved by the invention]

[0007] Incidentally, in a battery pack having a plurality of battery modules, input and output may be restricted if the SOC of the battery modules varies. [Means for solving the problem]

[0008] The secondary battery system disclosed herein includes a plurality of battery modules connected in series and a control device. Each of the plurality of battery modules includes a battery, a heating device, and a distribution circuit connected in parallel with the battery. The heating device is wired so that it can be fed with power through the distribution circuit, and is configured to generate a higher amount of heat depending on the feed power. The control device is configured to execute a first process for determining the feed power to be fed to the heating device of a battery module such that the higher the SOC or charge level of a battery module among the plurality of battery modules, the higher the power to be fed to the heating device in that battery module.

[0009] According to this secondary battery system, the variation in SOC among the multiple battery modules is suppressed, and thus the input / output of the secondary battery system is less likely to be restricted due to the variation in SOC.

[0010] Each of the battery modules may include a temperature sensor. The control device is configured to execute a second process, which determines the power to be supplied to the heating device, for a battery module among the battery modules whose temperature is lower than a predetermined temperature, in priority to the first process, so that the battery module reaches the predetermined temperature. According to this secondary battery system, the battery modules whose temperatures are lower than the predetermined temperature are eliminated early, and the variation in SOC is suppressed. This makes it difficult for the input and output of the secondary battery system to be restricted due to the variation in SOC.

[0011] The invention disclosed herein may be a control device for a secondary battery system, a control method, and a program for the control device for a secondary battery system. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic diagram showing a configuration example of a secondary battery system 10. As shown in FIG. [Diagram 2] FIG. 2 is a schematic diagram showing a configuration example of the distribution circuit 11d. [Diagram 3] FIG. 3 is a conceptual diagram showing an example in which the first process is applied. [Figure 4] FIG. 4 is a conceptual diagram showing an example in which the second process is applied with priority over the first process. [Diagram 5] FIG. 5 is a flowchart showing an example of a control flow of the secondary battery system 10 disclosed herein. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, the embodiments disclosed herein will be described. Of course, the embodiments described herein are not intended to limit the disclosure herein. The disclosure herein is not limited to the embodiments described herein unless otherwise specified. Each drawing is drawn typically and does not necessarily reflect the actual product. In addition, the same reference numerals are appropriately used for components and parts that perform the same function, and duplicated explanations are omitted.

[0014] <Secondary Battery System 10> Fig. 1 is a schematic diagram showing a configuration example of a secondary battery system 10. As shown in Fig. 1, the secondary battery system 10 includes a plurality of battery modules 11 and a control device 12. The secondary battery system 10 may be, for example, a system mounted on a vehicle as a battery system for a battery EV (Battery Electric Vehicle). The secondary battery system 10 is also called a battery pack.

[0015] The multiple battery modules 11 are connected in series. Each of the multiple battery modules 11 includes a battery 11a, a heating device 11b, a temperature sensor 11c, and a distribution circuit 11d. In Fig. 1, the multiple battery modules 11 and the components of the multiple battery modules 11 are distinguished by numbers in parentheses. In the specification, when the multiple battery modules 11 and the components of the multiple battery modules 11 are distinguished, the numbers in parentheses are appropriately added in the description.

[0016] The battery 11a of the battery module 11 is configured as an assembled battery. In this embodiment, the battery 11a is configured as an assembled battery in which a predetermined number of battery cells are combined, and the designed performance such as rated voltage and SOC is uniform. As a result, the designed performance such as rated voltage and SOC of each battery module 11 is uniform.

[0017] The heating device 11b may be a device whose temperature increases when electricity is applied. The heating device 11b may be configured as a device capable of electrically adjusting the amount of heat generated, such as an electric wire heater or a ceramic heater. The electric wire heater or the ceramic heater may be equipped with a thermostat, for example. In this embodiment, the heating device 11b is configured so that the amount of heat generated increases according to the power supply. The heating device 11b may be a heater capable of suppressing the amount of heating at high temperatures, such as a PTC heater. The heating device 11b is wired so that power can be supplied through the distribution circuit 11d.

[0018] The temperature sensor 11c is a sensor that measures the temperature of the battery module 11 to be controlled. In this embodiment, the temperature sensor 11c is attached to the battery 11a of the battery module 11. The temperature sensor 11c may be capable of converting temperature into a physical quantity such as a voltage or a resistance value and outputting the converted value. For example, a thermocouple, a thermistor, or a resistance temperature detector may be used as the temperature sensor 11c.

[0019] The distribution circuit 11d is a circuit connected in parallel with the batteries, and is a circuit wired so as to be able to supply power to the heating device 11b. In this embodiment, the multiple battery modules 11(1)-(4) are connected in series in order. The distribution circuit 11d is a circuit that distributes power from the batteries 11a of each battery module 11 to the heating device 11b. In other words, the distribution circuit 11d controls whether or not the power of the battery module is supplied to the heater. The distribution circuit 11d can also apply the voltage of the batteries 11a of each battery module 11 to the heating device 11b.

[0020] Fig. 2 is a schematic diagram showing a configuration example of the distribution circuit 11d. As shown in Fig. 2, the distribution circuit 11d can be composed of a switch 11d1 and a monitoring control circuit 11d2.

[0021] 2, the battery 11a of the battery module 11 has six battery cells connected in series. Here, unless otherwise specified, the number of cells of the battery 11a of the battery module 11 is not limited to six. The heating device 11b is configured to be able to heat the six battery cells of the battery 11a of the battery module 11. The temperature sensor 11c is attached to the battery 11a of the battery module 11.

[0022] The distribution circuit 11d is composed of a switch 11d1 and a monitoring control circuit 11d2. In this embodiment, the switch 11d1 is composed of a MOSFET (metal-oxide-semiconductor field-effect transistor). The monitoring control circuit 11d2 is connected to a detection line 11c1 of the temperature sensor 11c. This allows the monitoring control circuit 11d2 to obtain temperature information of the battery 11a. Furthermore, the monitoring control circuit 11d2 has a voltage detection line 11d3 that detects the applied voltage of the battery cell of the battery 11a of the battery module 11. This allows the monitoring control circuit 11d2 to obtain the voltage of the battery 11a of the battery module 11. In the embodiment shown in FIG. 2, the temperature sensor 11c is arranged so that the temperatures of some of the battery cells of the battery module 11 are obtained. The temperature sensor 11c may be arranged so that the temperatures of all the battery cells of the battery module 11 are obtained.

[0023] In the embodiment shown in FIG. 2, the monitoring control circuit 11d2 has a function of measuring the voltage and temperature of each cell of the battery module 11 to be monitored and transmitting the measured values ​​to the control device 12 (see FIG. 1). Here, the control device 12 is a device that controls the multiple battery modules 11(1)-(4) mounted in the secondary battery system 10. The control device 12 is also called a battery module controller (BMC). Upon receiving a command from the control device 12, the monitoring control circuit 11d2 controls the duty ratio of the switch 11d1 and controls the amount of heating by the heating device 11b. The monitoring control circuit 11d2 communicates with the monitoring control circuits 11d2 of other battery modules 11, and with other monitoring control circuits 11d2 and the control device 12.

[0024] The distribution circuit 11d outputs a signal to the switch 11d1, and can switch the switch 11d1 between ON and OFF. By turning the switch 11d1 ON, a voltage is applied to the heating device 11b. In this embodiment, the switch 11d1 is a MOSFET, and a predetermined duty ratio per period can be set. When an external voltage is applied to the battery module 11, the duty ratio represents the proportion of power supplied to the heating device 11b through the switch 11d1. For example, when the duty ratio is 30%, it indicates that the timing when the switch 11d1 is ON in the battery module 11 is 30%. In this case, it is indicated that the current is distributed to the heating device 11b at the timing of 30%, and the heating device 11b generates heat. Also, when the switch 11d1 is ON, the current is distributed to the heating device 11b, and the amount of charge to the battery 11a is reduced.

[0025] For example, in a secondary battery system 10 mounted on a battery-powered vehicle, when the vehicle is connected to an external power source and charging, the duty ratio of the switch 11d1 may be appropriately set for each battery module 11. This allows the amount of heat generated by the heating device 11b and the amount of charge to the battery 11a to be adjusted for each battery module 11. The battery 11a has a temperature suitable for operation, and if the battery 11a is placed in an extremely low temperature environment such as in a cold region, it becomes difficult to obtain the necessary input and output. In contrast, when the battery module 11 is being charged, the battery 11a is heated to an appropriate temperature by the heating device 11b, so that the resistance of the battery module 11 decreases, the charging current can be increased, and the vehicle can be started smoothly even in a cold region.

[0026] Furthermore, when no external voltage is applied to the battery module 11, the battery voltage of the battery 11a is applied to the heating device 11b when the switch 11d1 is turned ON. This allows the battery 11a to be heated using the battery voltage. When no external voltage is applied to the battery module 11, the switch 11d1 is turned ON and the voltage of the battery 11a is applied to the heating device 11b. This allows the heating device 11b to be operated using the power stored in the battery 11a, and the battery 11a can be heated.

[0027] In the configuration shown in FIG. 1, the multiple battery modules 11(1)-(4) are connected in series. Therefore, when the same current is applied to the multiple battery modules 11(1)-(4), they are charged in the same manner. Also, when the multiple battery modules 11(1)-(4) output power, they are discharged in the same manner. As a result, if there is variation in the SOC of the multiple battery modules 11(1)-(4), the performance of the battery modules 11(1)-(4) may not be fully exhibited.

[0028] For example, among multiple battery modules 11(1) to (4), assume that the SOC of battery module 11(1) is 45%, the SOC of battery module 11(2) is 50%, the SOC of battery module 11(3) is 55%, and the SOC of battery module 11(4) is 50%.

[0029] In this case, when the SOC of the battery module 11(3) reaches a predetermined upper limit, charging of the battery modules 11(1)-(4) must be stopped even if the SOC of the other battery modules 11(1,2,4) has not reached the upper limit. The same applies when discharging the multiple battery modules 11(1)-(4), and the SOC of the battery module 11(1) reaches a predetermined lower limit before the other battery modules 11(2,3,4). In this case, the output of the multiple battery modules 11(1)-(4) is restricted to match the battery module 11(1) whose SOC has reached its lower limit, for example by suppressing the output of the multiple battery modules 11(1)-(4).

[0030] In this way, the overall charge / discharge control of the multiple battery modules 11(1)-(4) can be limited in accordance with the battery module 11 whose SOC reaches the upper limit or lower limit first.

[0031] Also, there may be cases where a predetermined upper limit or lower limit is set for the charge amount. For example, when the battery system deteriorates and the full charge capacities of the battery modules 11 vary, control may be performed to equalize the charge amounts, rather than to make the SOC uniform. In such cases, too, if there is a large variation in the charge amounts of the battery modules 11, the overall charge / discharge control of the multiple battery modules 11(1)-(4) may be limited according to the battery module 11 whose charge amount reaches the upper limit or the lower limit first.

[0032] In other words, if there is variation in the SOC or charge amount of the battery modules 11 of the vehicle-mounted secondary battery system 10, the output and input are limited, and the secondary battery system 10 cannot maximize its capabilities. For this reason, the present inventor would like to control the secondary battery system 10 having multiple battery modules 11(1)-(4) so ​​as to reduce the variation in the SOC and charge amount of each battery module 11. On the other hand, in order to reduce the variation in the SOC and charge amount of the battery modules 11, it is necessary to consume power in the parts where there is variation. In this case, the applicant would like to effectively utilize the power of each battery module 11 and also suppress wasteful power consumption.

[0033] <Control device 12> 1, the control device 12 is configured to control the distribution circuit 11d of the multiple battery modules 11. In this embodiment, the control device 12 is configured to execute a first process and a second process.

[0034] <First Processing> The first process is a process for determining the power to be supplied to the heating device 11b of a battery module 11 such that the power to be supplied to the heating device 11b in a battery module 11 is higher for a battery module 11 having a higher SOC (State Of Charge) or charge amount among the plurality of battery modules 11. Here, SOC indicates the state of charge of the battery. For example, when a predetermined full charge is set to 100%, if the amount of charge of the battery is 70% of the charge amount of the full charge, it is expressed as SOC 70%. The charge amount is the amount of power charged to the battery, and can be expressed in units such as kWh. The charge amount can be defined as the amount of charge from a state in which the battery 11a is discharged by CCCV to a predetermined lower limit voltage. The first process can be applied when there is a variation in the SOC or charge amount of the plurality of battery modules 11(1) to (4).

[0035] FIG. 3 is a conceptual diagram showing an example in which the first process is applied. In the example shown in FIG. 3, the temperatures of the multiple battery modules 11(1)-(4) are each 0° C., which is the environmental temperature. The SOCs of the battery modules 11(1)-(4) vary, with the SOC of the battery module 11(1) being 45%, the SOC of the battery module 11(2) being 50%, the SOC of the battery module 11(3) being 55%, and the SOC of the battery module 11(4) being 50%. The first process is a process in which the power to be supplied to the heating device 11b of the battery module 11(3) having the highest SOC among the multiple battery modules 11(1)-(4) (in the above example, the battery module 11(3)) is determined so that the power to be supplied to the heating device 11b(3) of the battery module is high.

[0036] In the distribution circuit 11d shown in FIG. 2, the duty ratio of the switch 11d1 of the battery module 11(3) is set to be larger than that of the other battery modules 11(1,2,4). As a result, the power supplied to the heating device 11b(3) of the battery module 11(3) is larger than the power supplied to the heating device 11b(1,2,4) of the other battery modules 11(1,2,4). This suppresses the amount of charge to the battery module 11(3), and the difference in the amount of charge with the other battery modules 11(1,2,4) is kept small. For example, the duty ratio of the switch 11d1 of the battery module 11(3) having an SOC of 55% is set to 30%. The duty ratio of the switch 11d1 of the battery module 11(2,4) having an SOC of 50% is set to 20%. Furthermore, the duty ratio of the switch 11d1 of the battery module 11(1) having an SOC of 45% is set to 10%.

[0037] As a result, in the battery module 11(3), power is consumed by the heating device 11b(3), and the charging of the battery 11a(3) is kept low. On the other hand, in the battery module 11(1), power consumption by the heating device 11b(1) is reduced, and most of the power is used to charge the battery 11a(3). This reduces the difference in SOC between the battery module 11(1) and the battery module 11(3), and reduces the variation in SOC among the battery modules 11(1) to (4). After the variation in SOC among the battery modules 11(1) to (4) is eliminated, it is advisable to make the duty ratio of each switch 11d1 of the battery modules 11(1) to (4) uniform. By supplying power to the heating devices 11b of the battery modules 11(1) to (4), the variation in SOC can be reduced and the battery modules 11(1) to (4) can be heated to an appropriate temperature. This allows for effective use of power.

[0038] Here, it is assumed that at a duty ratio of 10%, the temperature of battery 11a rises by 5°C after 15 minutes. In this case, after 5 minutes, battery module 11(3) reaches 15°C, battery module 11(2,4) reaches 10°C, and battery module 11(1) reaches 5°C. In this manner, battery modules 11(1)-(4) are each heated according to the duty ratio of switch 11d1, and the charging speed is suppressed. Furthermore, after 15 minutes, all battery modules 11(1)-(4) reach 5°C or higher.

[0039] In this way, in the first process, the power supply of the battery module 11 having the highest SOC among the multiple battery modules 11(1)-(4) is determined so that the power supplied to the heating device of the battery module 11 having the highest SOC is high. As a result, in the first process, although the temperatures of the battery modules 11(1)-(4) vary, the variation in SOC of the multiple battery modules 11(1)-(4) is suppressed. This makes it difficult for input and output to be restricted due to the variation in SOC, and makes it easier for the secondary battery system 10 (battery pack) to demonstrate its capabilities.

[0040] Furthermore, the secondary battery system 10 mounted on the vehicle may incorporate a cooling device that cools the battery modules 11(1)-(4) by using a device that blows air with an air-cooling fan or circulates a refrigerant. In the secondary battery system 10 mounted on the vehicle, there may be some parts that are cooled quickly and other parts that are not, and this may cause variations in temperature among the multiple battery modules 11(1)-(4). On the other hand, the lower the temperature of a secondary battery containing a nonaqueous electrolyte, the higher the viscosity of the electrolyte and the higher the internal resistance, which tends to deteriorate the charge / discharge characteristics. For this reason, the battery module 11 tends to have a higher battery resistance at lower temperatures.

[0041] In particular, in an extremely cold environment, the output characteristics are reduced. For this reason, in the secondary battery system 10 of a battery-powered vehicle, a minimum temperature may be set as a temperature suitable for driving. The minimum temperature may be set in the control device 12 that controls the battery modules 11 (1) to (4). The minimum temperature may be, for example, about -5°C to +5°C. In order to maintain the running performance and charging performance of the vehicle, it is necessary to maintain the battery temperature at or above the minimum temperature. In the secondary battery system 10 mounted on the vehicle, the size is large, so that temperature variations are likely to occur between battery modules and even between battery cells, but as long as the temperature is above the minimum temperature, the required charging and discharging performance is maintained. Conversely, the higher the temperature of the battery, the greater the self-discharge. For this reason, the SOC decreases and variations occur. For this reason, it is usually required that the temperature management in the battery pack be kept within a certain range, for example, within an upper and lower limit of 5°C. Also, if the temperature of the battery becomes too high, it will cause a decrease in the lifespan of the battery. For this reason, an upper limit temperature for use is set. The upper limit temperature for use may be set to, for example, 65°C.

[0042] <Second Processing> The second process is a process that takes precedence over the first process and determines the power supply to be supplied to the heating device for a battery module among the multiple battery modules 11(1)-(4) whose temperature is lower than a predetermined temperature so that the battery module reaches the predetermined temperature.

[0043] For example, suppose that the predetermined temperature of battery modules 11(1)-(4) is set to 5° C. At this time, suppose that there is a variation in temperature among battery modules 11(1)-(4), with battery module 11(1) at 5° C., battery module 11(2) at −5° C., battery module 11(3) at 0° C., and battery module 11(4) at 5° C.

[0044] In this case, the temperature of the battery module 11(2,3) is lower than the predetermined temperature (5° C.). In the second process, for the battery module 11(2,3) whose temperature is lower than the lowest temperature, the power to be supplied to the heating device is determined so that the battery module 11(2,3) reaches the predetermined temperature (5° C.). This determination is given priority over the first process.

[0045] When the first process is not taken into consideration, for example, the duty ratio of the switch 11d1 of the battery module 11(2,3) is set to 30%, the duty ratio of the battery module 11(1,4) is set to 10%, and power is supplied to the heating device 11b. This may allow the battery module 11(2,3) to be heated to a temperature higher than the minimum temperature early. The duty ratio of the switch 11d1 of the battery modules 11(1)-(4) may be reviewed at predetermined time intervals. For example, temperature information may be obtained from the battery modules 11(1)-(4) every 15 minutes to determine whether the temperature is lower than the minimum temperature.

[0046] In the second process, the first process is applied while further considering the SOC of the battery modules 11(1)-(4). That is, in the first process, the power to be supplied to the heating device 11b of a battery module is determined such that the higher the SOC or the charge amount of a battery module among the multiple battery modules 11(1)-(4), the higher the power to be supplied to the heating device 11b of that battery module.

[0047] Fig. 4 is a conceptual diagram showing an example in which the second process is applied preferentially to the first process. In the example shown in Fig. 4, the battery module 11(1) is at 5°C and SOC 45%, the battery module 11(2) is at -5°C and SOC 50%, the battery module 11(3) is at 0°C and SOC 55%, and the battery module 11(4) is at 5°C and SOC 50%. In this case, the second process takes precedence over the first process, and for the battery module 11(2,3) whose temperature is lower than a predetermined temperature among the multiple battery modules 11(1) to (4), the power to be supplied to the heating devices 11b(2) and (3) is determined so that the battery module 11(2,3) reaches the predetermined temperature.

[0048] In this embodiment, the duty ratio of the battery module 11(2) with an SOC of 50% is set to 20%, and the duty ratio of the battery module 11(3) with an SOC of 55% is set to 30%. The first process is applied to the battery module 11(1,4) with a predetermined temperature (5°C). In this embodiment, the duty ratio of the switch 11d1 of the battery module (1,4) is set to 0% for the battery module 11(1) with an SOC of 45%, and 20% for the battery module 11(4) with an SOC of 50%. With a duty ratio of 10%, the battery module 11 is heated by 5°C after 15 minutes. After 15 minutes, the battery module 11(2) reaches the predetermined temperature of 5°C. The battery modules 11(3,4) are each at 15°C.

[0049] Further, after that, the first process is executed, the duty ratio of the switch 11d1 of each battery module 11 is controlled, and the duty ratio of the battery with a high SOC is set high. This reduces the variation in SOC. After the variation in SOC of the battery modules 11(1)-(4) is eliminated, the duty ratio of each switch 11d1 of the battery modules 11(1)-(4) may be made uniform. In this way, in the second process, the power to be supplied to the heating device 11b is determined in priority to the first process for the battery module 11 having a temperature lower than a predetermined temperature among the multiple battery modules 11(1)-(4) so ​​that the battery module 11 reaches the predetermined temperature. After that, the variation in SOC is suppressed by the first process. As a result, the battery modules 11(1)-(4) quickly reach the predetermined temperature, and then the variation in SOC is suppressed by the first process.

[0050] In this embodiment, the secondary battery system 10 is an on-board system for an electric vehicle (battery EV). The secondary battery system 10 is configured such that the control device 12 operates when the electric vehicle is connected to an external power source so as to be chargeable. In other words, the control device 12 controls the power supply to the heating device 11b of each battery module 11 while the on-board secondary battery system 10 is charging, thereby suppressing variations in SOC. Here, the state in which the electric vehicle is connected to an external power source so as to be chargeable may be when it is connected to a charging plug at a charging stand, or may be when it is connected to an external power source so as to be chargeable in a non-contact manner.

[0051] The secondary battery system 10 is an on-board system for an electric vehicle, and the control device 12 may be configured to operate so that the secondary battery system 10 can perform predetermined charging and discharging in accordance with the scheduled departure time of the electric vehicle. In other words, the control device 12 controls the power supply to the heating device 11b of each battery module 11 of the on-board secondary battery system 10 in accordance with the scheduled departure time, and it is preferable that the variation in SOC is suppressed. As a result, when the vehicle departs, the SOCs of the battery modules 11 of the secondary battery system 10 are uniform, and the secondary battery system 10 is more likely to demonstrate its capabilities.

[0052] The secondary battery system 10 is an on-board system for an electric vehicle, and may be configured to supply power from the battery 11a to the heating device 11b based on the temperature and the SOC or charge amount of each of the multiple battery modules 11(1)-(4). For example, when the vehicle is parked, the battery voltage of the battery 11a of the battery module 11 may be applied to the heating device 11b by the above-mentioned first process or second process. This maintains the temperature of the battery module 11 at or above a predetermined temperature, and reduces the variation in the SOC of the battery module 11. This makes it easier for the secondary battery system 10 to demonstrate its capabilities.

[0053] The secondary battery system 10 is an in-vehicle system for an electric vehicle, and in the second process, when the electric vehicle is not connected to an external power source so as to be rechargeable, the predetermined temperature may be set lower than when the electric vehicle is connected to an external power source so as to be rechargeable. For example, when the electric vehicle is connected to an external power source so as to be rechargeable, the vehicle is in a state where it is powered, so it is preferable that the predetermined temperature is set to a temperature at which the vehicle can run, and the heating device 11b is controlled. On the other hand, when the battery module 11 is not connected to a rechargeable external power source, the vehicle is in a state where it is not powered, so it is preferable that the predetermined temperature is set lower so as not to interfere with the running of the vehicle. As a result, while maintaining the battery module 11 at a temperature at which it is not difficult to run the vehicle, priority is given to ensuring the remaining battery capacity.

[0054] FIG. 5 is a flowchart showing an example of a control flow of the secondary battery system 10 disclosed herein.

[0055] 5, in the secondary battery system 10, first, information on cell voltages and temperatures is acquired from the multiple battery modules 11 included in the secondary battery system 10 (S11). Next, it is determined whether or not the cell temperatures acquired from the multiple battery modules 11 are higher than a predetermined temperature T1 (S12).

[0056] In this determination (S12), if the cell temperatures acquired from the plurality of battery modules 11 are not higher than the predetermined temperature T1 (No), the above-mentioned second process (S2) is executed.

[0057] In the control flow shown in FIG. 5, the following steps S31 to S35 are executed in the second process S2. S31: Calculate the amount of heating required for the coldest battery module 11 to reach the minimum temperature among the multiple battery modules 11. In the above-described embodiment, it is preferable to calculate the duty ratio required for the coldest battery module 11 to reach the minimum temperature within a predetermined time. S32: Among the plurality of battery modules 11, the battery module 11 with the lowest SOC is identified. S33: Calculate the discharge amount (Ah) for equalizing the SOC or charge amount of the plurality of battery modules 11. S34: The duty ratio of each battery module 11 calculated in accordance with the discharge amount calculated in S33 is added to the duty ratio calculated in S31. S35: The duty ratio is transmitted to the monitoring control circuit 11d2 (see FIG. 2) of each battery module 11, the switch 11d1 is controlled, and discharging to the warming device 11b is started.

[0058] By the second process (S2), the battery modules 11 whose cell temperatures are not higher than a predetermined temperature T1 are heated, and the SOCs of the multiple battery modules 11 are equalized.

[0059] In the determination (S12), if the cell temperatures acquired from the multiple battery modules 11 are higher than a predetermined temperature T1 (Yes), it is determined whether the SOCs of the multiple battery modules 11 are uniform (S13). If the SOCs of the multiple battery modules 11 are not uniform (No), a first process (S1) for equalizing the SOCs of the multiple battery modules 11 is executed.

[0060] In the control flow shown in FIG. 5, the following processes S41 to S44 are executed in the second process S1. S41: Among the plurality of battery modules 11, the battery module 11 with the lowest SOC is identified. S42: The discharge amount (Ah) for equalizing the SOC or charge amount of the plurality of battery modules 11 is calculated. S43: The duty ratio of each battery module 11 is calculated based on the discharge amount calculated in S42. S44: The duty ratio is transmitted to the monitoring control circuit 11d2 (see FIG. 2) of each battery module 11, the switch 11d1 is controlled, and discharging to the warming device 11b is started.

[0061] In the first process (S1), discharging to the heater 11b of the battery module 11 heats the battery module 11 and equalizes the SOC of the multiple battery modules 11.

[0062] 5, if the SOCs of the multiple battery modules 11 are the same (Yes) in the determination (S13), a process (S45) is executed to set the duty ratios of the multiple battery modules 11 to 0%. This process (S45) stops the power supply to the heating device 11b, and thus stops the discharge for heating. This allows the power of the battery module 11 to be maintained, and all of it is used for charging during charging.

[0063] 5 shows that the SOCs of the multiple battery modules 11 are equalized, but the multiple battery modules 11 may be controlled to have equal amounts of charge. For example, in the secondary battery system 10, when the state of charge of the battery modules 11 is managed by the SOC and an upper limit voltage and a lower limit voltage are set, it is preferable to equalize the SOCs. Also, when the state of charge of the battery modules 11 is managed by the charge amount and an upper limit charge amount and a lower limit charge amount are set, it is preferable to equalize the charge amounts.

[0064] 5 shows an example of a control flow of the secondary battery system 10. Unless otherwise specified, the control flow of the secondary battery system 10 is not limited to the control flow shown in FIG.

[0065] The control device 12 disclosed here is a control device for a secondary battery system 10 including a plurality of battery modules 11. As shown in FIG. 1, each of the plurality of battery modules 11 includes a battery 11a, a heating device 11b, a temperature sensor 11c, and a distribution circuit 11d connected in parallel to the battery 11a. The heating device 11b is wired so as to be able to receive power through the distribution circuit 11d, and is configured so that the amount of heat generated by the heating device 11b increases according to the power supplied. A first process S1 (see FIG. 5) is executed to determine the power to be supplied to the heating device 11b of the battery module 11, so that the power supplied to the heating device 11b in the battery module 11 increases as the SOC or charge level of the battery module 11 increases.

[0066] The control device 12 may be configured to execute, in priority to the first process S1, a second process S2 (see FIG. 5) for determining the power supply to be supplied to the heating device 11b for a battery module 11 among the plurality of battery modules 11 that has a temperature lower than a predetermined temperature so that the battery module 11 reaches the predetermined temperature.

[0067] A control device 12 disclosed herein is incorporated into a secondary battery system 10, for example, as shown in FIG.

[0068] The control method disclosed herein is a control method for a secondary battery system 10 including a plurality of battery modules 11. As shown in FIG. 1, each of the plurality of battery modules 11 includes a battery 11a, a heating device 11b, a temperature sensor 11c, and a distribution circuit 11d connected in parallel to the battery 11a. The heating device 11b is wired so as to be able to receive power through the distribution circuit 11d, and is configured to generate a higher amount of heat depending on the power supply. A first process S1 (see FIG. 5) is executed to determine the power supply to be supplied to the heating device 11b of the battery module 11, so that the power supplied to the heating device 11b in the battery module 11 having a higher SOC or charge level is higher.

[0069] The control method may be configured such that, in priority to the first process S1, a second process S2 (see FIG. 5) is executed for a battery module 11 among the plurality of battery modules 11 that has a temperature lower than a predetermined temperature, in order to cause the battery module 11 to reach the predetermined temperature.

[0070] The control method disclosed herein can be used in a secondary battery system 10 mounted on a vehicle, as shown in FIG.

[0071] The program disclosed here is a program for a control device 12 of a secondary battery system 10 including a plurality of battery modules 11. As shown in Fig. 1, each of the battery modules 11 includes a battery 11a, a heater 11b, a temperature sensor 11c, and a distribution circuit 11d connected in parallel to the battery 11a. The heater 11b is wired so as to be able to receive power through the distribution circuit 11d, and is configured so that the amount of heat generated increases according to the power supplied. A first process S1 (see Fig. 5) is executed to determine the power to be supplied to the heater 11b of the battery module 11, so that the power supplied to the heater 11b in the battery module 11 increases as the SOC or charge level of the battery module 11 increases.

[0072] The program may be configured to execute, in priority to the first process S1, a second process S2 (see FIG. 5) for determining the power supply to be supplied to the heating device 11b for a battery module 11 among the plurality of battery modules 11 that has a temperature lower than a predetermined temperature so that the battery module 11 reaches the predetermined temperature.

[0073] Here, the program may be configured such that, when the secondary battery system is an on-board system for an electric vehicle, the control device operates when the electric vehicle is connected to an external power source so as to be chargeable. Also, the program may be configured such that, when the secondary battery system is an on-board system for an electric vehicle, the control device operates in accordance with a scheduled departure time of the electric vehicle. Also, when the secondary battery system is an on-board system for an electric vehicle, the program may be configured such that the battery supplies power to the heating device based on the temperature of each of the plurality of battery modules and the SOC or the charge amount. Also, when the secondary battery system is an on-board system for an electric vehicle, the program may be configured such that, when the electric vehicle is not connected to be chargeable from the external power source, the predetermined temperature is set lower than when the electric vehicle is connected to be chargeable from the external power source.

[0074] The program disclosed herein is written into the vehicle's control device and introduced into the vehicle's control device and BMC. For example, a program may be distributed to the vehicle, and the vehicle's control device and BMC may be updated, so that the program is incorporated into the vehicle's control device and the control device and BMC function according to the program.

[0075] Here, the program may be stored in, for example, a non-transitory computer readable medium. The program may be supplied to the computer through such a non-transitory computer readable medium. Examples of non-transitory computer readable media include magnetic recording media (e.g., flexible disks, magnetic tapes, hard disk drives), CD-ROMs (Read Only Memory), etc.

[0076] Here, the control device is typically a computer, and may include a storage device (such as a memory) and an arithmetic device (such as a CPU). Each process of the control device is embodied as a processing module executed by a predetermined program. Each function of the control device can be appropriately embodied by cooperation between physical components and control based on the results of calculations performed according to the predetermined program.

[0077] The control device may be a device in which a plurality of control devices cooperate with each other. For example, when the control device is connected to an external computer via a LAN cable, the Internet, or the like so as to be able to perform data communication, the processing of the control device may be performed in cooperation with such an external computer. For example, the information or a part of the information stored in the control device may be stored by an external computer, and the processing or a part of the processing performed by the control device may be performed by an external computer.

[0078] The secondary battery may be a power storage element configured to be chargeable and dischargeable. The secondary battery is not particularly limited. The secondary battery may be, for example, a secondary battery such as a lithium ion battery or a nickel hydrogen battery, or a storage element such as an electric double layer capacitor. The lithium ion secondary battery is a secondary battery that uses lithium as a charge carrier. The lithium ion secondary battery may be a lithium ion secondary battery with a liquid electrolyte, or a so-called all-solid-state battery that uses a solid electrolyte.

[0079] The invention disclosed herein has been described in various ways. Unless otherwise specified, the embodiments described herein do not limit the present invention. Furthermore, the embodiments of the invention disclosed herein can be modified in various ways, and each component or each process described herein can be omitted or combined as appropriate, unless a particular problem occurs. [Explanation of symbols]

[0080] 10. Secondary Battery System 11 Battery module 11a battery 11b Warming device 11c Temperature Sensor 11c1 Temperature sensor 11c detection wire 11d distribution circuit 11d1 Switch 11d2 Monitoring control circuit 11d3 Voltage detection wire 12 Control device

Claims

1. A plurality of battery modules connected in series; Control device and Equipped with Each of the battery modules includes a plurality of batteries connected in series, a heating device, and a distribution circuit connected in parallel to the plurality of batteries; The heating device is wired so as to be able to receive power through the distribution circuit, and is configured so that the amount of heat generated increases according to the power supply, The control device includes: a first process is executed to determine a supply power of the battery module to be supplied to the heating device such that a battery module having a higher SOC or a higher charge amount among the plurality of battery modules supplies a higher power to the heating device in the battery module; Here, the distribution circuit includes a switch and a monitoring control circuit, The monitoring control circuit is configured to receive a command from the control device and control a predetermined duty ratio per one period of the switch, In the first process, the duty ratio is controlled so that a current is distributed to a current for charging a battery module including the distribution circuit among the plurality of battery modules and a current flowing to the heating device of the battery module including the distribution circuit in order to heat the battery module. Secondary battery system.

2. Each of the battery modules includes a temperature sensor; The control device includes: a second process is executed to determine a power supply to be supplied to the heating device, for a battery module having a temperature lower than a predetermined temperature among the plurality of battery modules, in order to cause the battery module to reach the predetermined temperature, in preference to the first process; The secondary battery system according to claim 1 .

3. 3. The secondary battery system according to claim 1 or 2, wherein the secondary battery system is an on-board system for an electric vehicle, and the control device is configured to operate when the electric vehicle is connected to an external power source in a chargeable manner.

4. 3. The secondary battery system of claim 1 or 2, wherein the secondary battery system is an on-board system for an electric vehicle, and the control device is configured to operate so as to enable predetermined charging and discharging in accordance with the scheduled departure time of the electric vehicle.

5. 3. The secondary battery system of claim 1 or 2, wherein the secondary battery system is an on-board system for an electric vehicle, and is configured to supply power from the battery to the heating device based on the temperature of each of the plurality of battery modules and an SOC or a charge amount.

6. 3. The secondary battery system according to claim 2, wherein the secondary battery system is an on-board system for an electric vehicle, and when the electric vehicle is not connected so as to be chargeable from an external power source, the predetermined temperature is set lower than when the electric vehicle is connected so as to be chargeable from an external power source.

7. A control device for a secondary battery system having a plurality of battery modules, The plurality of battery modules include Each of the batteries is connected in series, and the heating device, the temperature sensor, and the distribution circuit is connected in parallel to the batteries. The heating device includes: The power supply is provided through the distribution circuit, and the heat generation amount is increased according to the power supply. Here, the distribution circuit includes a switch and a monitoring control circuit, The monitoring control circuit is configured to receive a command from the control device and control a predetermined duty ratio per one period of the switch, a first process is executed to determine a supply power of the battery module to be supplied to the heating device such that a battery module having a higher SOC or a higher charge amount among the plurality of battery modules supplies a higher power to the heating device in the battery module; a control device configured to control the duty ratio in the first process so that a current is distributed to a current for charging a battery module among the plurality of battery modules that is equipped with the distribution circuit, and a current flowing to the heating device of the battery module that is equipped with the distribution circuit in order to heat the battery module.

8. a second process is executed to determine a power supply amount to be supplied to the heating device for a battery module having a temperature lower than a predetermined temperature among the plurality of battery modules, in order to cause the battery module to reach the predetermined temperature, in preference to the first process; 8. The control device according to claim 7.

9. 9. The control device according to claim 7 or 8, wherein the secondary battery system is an on-board system for an electric vehicle, and the control device is configured to operate when the electric vehicle is connected to an external power source so as to be chargeable.

10. 9. The control device according to claim 7 or 8, wherein the secondary battery system is an on-board system for an electric vehicle, and the control device is configured to operate so as to enable predetermined charging and discharging in accordance with a scheduled departure time of the electric vehicle.

11. 9. The control device according to claim 7 or 8, wherein the secondary battery system is an on-board system for an electric vehicle, and is configured to supply power from the battery to the heating device based on the temperature of each of the plurality of battery modules and an SOC or a charge amount.

12. 9. The control device according to claim 8, wherein the secondary battery system is an on-board system for an electric vehicle, and when the electric vehicle is not connected so as to be chargeable from an external power source, the predetermined temperature is set lower than when the electric vehicle is connected so as to be chargeable from an external power source.

13. A control method for a secondary battery system including a plurality of battery modules, comprising: The plurality of battery modules include The battery pack includes a plurality of batteries connected in series, a heating device, a temperature sensor, and a distribution circuit connected in parallel to the plurality of batteries, and is configured to be controlled by a control device; The heating device includes: The power supply is provided through the distribution circuit, and the heat generation amount is increased according to the power supply. Here, the distribution circuit includes a switch and a monitoring control circuit, The monitoring control circuit is configured to control a predetermined duty ratio per one period of the switch in response to a command from the control device, a control method for determining a power supply to be supplied to the heating device of a battery module such that a battery module having a higher SOC or charge level supplies a higher power to the heating device in the battery module, and controlling the duty ratio, thereby distributing a current to a current for charging a battery module having the distribution circuit among the battery modules and a current flowing to the heating device of the battery module for heating the battery module having the distribution circuit.

14. In preference to the control method, a power supply to be supplied to the heating device is determined for a battery module having a temperature lower than a predetermined temperature among the plurality of battery modules so that the battery module reaches the predetermined temperature.

14. A control method according to claim 13.

15. 15. The control method according to claim 13, wherein the secondary battery system is an on-board system for an electric vehicle, and the control method is configured to be executed when the electric vehicle is connected to an external power source in a chargeable manner.

16. 15. The control method according to claim 13, wherein the secondary battery system is an on-board system for an electric vehicle, and the control method is configured to be executed so that predetermined charging and discharging can be performed in accordance with a scheduled departure time of the electric vehicle.

17. 15. The control method according to claim 13 or 14, wherein the secondary battery system is an on-board system for an electric vehicle, and is configured to supply power from the battery to the heating device based on the temperature of each of the plurality of battery modules and an SOC or a charge amount.

18. 15. The control method according to claim 14, wherein the secondary battery system is an on-board system for an electric vehicle, and when the electric vehicle is not connected so as to be chargeable from an external power source, the predetermined temperature is set lower than when the electric vehicle is connected so as to be chargeable from an external power source.

19. A program for a control device of a secondary battery system having a plurality of battery modules, The plurality of battery modules include The battery pack includes a plurality of batteries connected in series, a heating device, a temperature sensor, and a distribution circuit connected in parallel to the plurality of batteries, and is configured to be controlled by a control device; The heating device includes: The power supply is provided through the distribution circuit, and the heat generation amount is increased according to the power supply. Here, the distribution circuit includes a switch and a monitoring control circuit, The monitoring control circuit is configured to control a predetermined duty ratio per one period of the switch in response to a command from the control device, A control device for a secondary battery system including the plurality of battery modules, a first process is executed to determine a supply power of the battery module to be supplied to the heating device such that a battery module having a higher SOC or a higher charge amount among the plurality of battery modules supplies a higher power to the heating device in the battery module; a program configured so that in the first process, the duty ratio is controlled so that a current is distributed between a current for charging a battery module among the plurality of battery modules that is equipped with the distribution circuit and a current flowing to the heating device of the battery module that is equipped with the distribution circuit in order to heat the battery module.

20. The control device, a second process is executed to determine a power supply to be supplied to the heating device for a battery module having a temperature lower than a predetermined temperature among the plurality of battery modules, in priority to the first process, so that the battery module reaches the predetermined temperature; 20. The program according to claim 19.

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