Electricity storage control method and electricity storage control system

Abstract

To enable suppression of imbalance in the charge of storage batteries due to temperature.SOLUTION: A power storage control method for controlling the charging and discharging of a battery module that constitutes a storage battery used in a storage battery unit, includes a process for detecting the temperature of the battery module and a process for setting the on-time of a detection element that detects the state of the battery module according to the temperature of the battery module.SELECTED DRAWING: Figure 11

Description

[Technical field]

[0001] The present invention relates to a power storage control method and a power storage control system. [Background technology]

[0002] Power supply systems in which solar panels are installed on the roofs of houses and the electricity generated by the solar panels is used as household electricity are becoming widespread. As a storage battery unit for use in such a power supply system, a configuration has been proposed in which a plurality of battery cells are connected in series to form a battery stack so that a desired voltage can be obtained (for example, Patent Document 1). For example, the voltage of a lithium-ion battery cell is about 2V to 4V. In contrast, the voltage of a household power supply is several hundred volts. In this case, several dozen battery cells are connected in series to ensure a voltage of several hundred volts for household use. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-156200 A Summary of the Invention [Problem to be solved by the invention]

[0004] Generally, a storage battery has the characteristic that the higher the temperature, the faster the lifespan deteriorates, and the lower the temperature, the lower the charging capacity. Therefore, a temperature detection element is provided in each part of the storage battery unit. A thermistor is generally used as the temperature detection element. A thermistor is an element whose electrical resistance changes depending on the temperature. The thermistor is provided in a circuit provided in the storage battery, and when the temperature is measured using the thermistor, the circuit is consumed for the time the thermistor is on, and thus the capacity of the storage battery is consumed. This causes an imbalance in the charge amount of the storage battery.

[0005] In view of the above-mentioned problems, an object of the present invention is to provide an electricity storage control method and an electricity storage control system that can suppress imbalance in the charge amounts of storage batteries caused by temperature. [Means for solving the problem]

[0006] A power storage control method according to one aspect of the present invention is a power storage control method for controlling charging and discharging of a battery module constituting a storage battery used in a storage battery unit, and includes a step of detecting a temperature of the battery module, and a step of setting an on-time of a detection element that detects a state of the battery module in accordance with the temperature of the battery module. The storage battery includes a plurality of battery modules connected in series, the detection element is provided for each of the battery modules, and the on-time is set so that the amount of discharge consumed by each detection element is uniform.

[0007] According to one aspect of the present invention, there is provided an energy storage control system for controlling charging and discharging of a battery module constituting a storage battery used in a storage battery unit, the energy storage control system including: a detection element for detecting a state of the battery module; and a sensor setting unit for setting an on-time of the detection element in accordance with a temperature of the battery module. The storage battery includes a plurality of battery modules connected in series, the detection element is provided for each of the battery modules, and the on-time is set so that the amount of discharge consumed by each detection element is uniform. Effect of the Invention

[0008] According to the present invention, the ON time of the detection element that detects the state of the battery module is set according to the temperature of the battery module, thereby making it possible to balance the charge amounts among the battery modules, thereby suppressing imbalances in the charge amounts of the storage batteries. [Brief description of the drawings]

[0009] [Figure 1] 1 is a block diagram showing an overview of a power supply system according to the present invention; [Diagram 2] FIG. 1 is an explanatory diagram illustrating an overview of a storage battery unit used in a power supply system according to the present invention. [Diagram 3] 1 is an explanatory diagram illustrating an overview of a relay cable that connects a connector of a battery module and a connector of a control management module. [Figure 4]1 is an explanatory diagram illustrating an overview of a relay cable that connects a connector of a battery module and a connector of a control management module. [Diagram 5] FIG. 2 is an explanatory diagram of an example of a battery module. [Figure 6] FIG. 2 is a block diagram showing a configuration of a control management module. [Figure 7] FIG. 2 is a block diagram showing an overview of an AFE circuit element disposed on a BMS substrate. [Figure 8] 1 is a block diagram showing an overview of a power storage control system according to an embodiment of the present invention; [Figure 9] 1 is a graph showing the relationship between temperature and resistance value of a thermistor. [Figure 10] FIG. 4 is an explanatory diagram of a switch control time of the power storage control system according to the embodiment of the present invention. [Figure 11] 2 is a flowchart used to explain the power storage control system according to an embodiment of the present invention. [Figure 12] FIG. 13 is a block diagram showing an outline of another configuration example of a power supply system according to the present invention. [Figure 13] FIG. 13 is a block diagram showing an outline of another configuration example of a power supply system according to the present invention. [Figure 14A] FIG. 11 is a diagram showing another example of a configuration for processing a detected voltage of a thermistor according to the present invention. [Figure 14B] FIG. 11 is a diagram showing another example of a configuration for processing a detected voltage of a thermistor according to the present invention. [Figure 14C] FIG. 11 is a diagram showing another example of a configuration for processing a detected voltage of a thermistor according to the present invention. [Figure 14D] FIG. 11 is a diagram showing another example of a configuration for processing a detected voltage of a thermistor according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0011] <Overall system> First, an overview of a power supply system 10 according to the present invention will be described with reference to Fig. 1. Fig. 1 is a block diagram showing an overview of a power supply system 10 according to the present invention. As shown in FIG. 1, a power supply system 10 according to an embodiment of the present invention includes a power conditioner 1, a solar panel 2, and a storage battery unit 3.

[0012] The power conditioner 1 performs processes such as conversion between DC and AC power, control of power supply voltage, and buying and selling electricity. That is, while the commercial power supply 5 uses AC power, solar power generation and electricity storage use DC power. Also, the voltage of the commercial power supply 5 and the voltage of the batteries used in the solar panel 2 and the storage battery unit 3 are different. The power conditioner 1 performs conversion between DC and AC power and controls the power supply voltage between the commercial power supply 5, the solar panel 2, and the storage battery unit 3. The power conditioner 1 then supplies power to the distribution board 6, which distributes the power to the outlets in each room.

[0013] The solar panel 2 can generate electricity during the daytime when the sun is out, but cannot generate electricity at night when the sun sets, and the amount of electricity generated is unstable. The storage battery unit 3 can be charged from the grid via the commercial power source 5 and power conditioner 1 during the day, and can also be charged via the solar panel 2 and power conditioner 1, and can also supplement the power supply via the power conditioner 1. The storage battery unit 3 can be charged from the grid via the commercial power source 5 and power conditioner 1 at night, and can also supplement the power supply via the power conditioner 1.

[0014] In addition, the power conditioner 1 performs processes such as purchasing and selling power, such as purchasing power from a commercial power source 5 when there is a power shortage, and selling power to the commercial power source 5 when there is surplus power from the solar panel 2.

[0015] An EV (Electric Vehicle) stand 4 can also be incorporated into the power supply system 10. The EV stand 4 can be used to charge an electric vehicle, as well as to store power using a battery installed in the electric vehicle. The EV stand 4 can also supplement the power supply via the power conditioner 1.

[0016] Here, an overview of the storage battery unit 3 used in the power supply system 10 according to the present invention will be described with reference to Fig. 2. Fig. 2 is an explanatory diagram illustrating the overview of the storage battery unit 3 used in the power supply system 10 according to the present invention.

[0017] 2, the storage battery unit 3 includes, for example, seven battery modules 11-1 to 11-7 and a control management module 12. The battery modules 11-1 to 11-7 include a battery stack including a plurality of battery cells. The battery modules 11-1 to 11-7 also include connectors 13-1 to 13-7 and connectors 14-1 to 14-7, respectively.

[0018] The control management module 12 manages the charge / discharge states of the battery modules 11-1 to 11-7. The control management module 12 is provided with connectors 45-1 to 45-7 and connectors 56-1 to 56-7.

[0019] The connectors 13-1 to 13-7 of the battery modules 11-1 to 11-7 and the connectors 45-1 to 45-7 of the control management module 12 are connected by relay cables 60-1 to 60-7 as shown in Fig. 3. The connectors 14-1 to 14-7 of the battery modules 11-1 to 11-7 and the connectors 56-1 to 56-7 of the control management module 12 are connected by relay cables 70-1 to 70-7 as shown in Fig. 4.

[0020] FIG. 3 is an explanatory diagram illustrating an outline of relay cables 60 (60-1 to 60-7) that connect the connectors 13-1 to 13-7 of the battery modules 11-1 to 11-7 and the connectors 45-1 to 45-7 of the control management module 12. As shown in FIG.

[0021] Here, an overview of the relay cable that connects the connector of the battery module and the connector of the control management module will be described with reference to Figs. 3 and 4.

[0022] FIG. 3 is an explanatory diagram illustrating an outline of relay cables 60 (60-1 to 60-7) that connect the connectors 13-1 to 13-7 of the battery modules 11-1 to 11-7 and the connectors 45-1 to 45-7 of the control management module 12. As shown in FIG.

[0023] 3, the relay cable 60 is made up of connectors 61 (61-1 to 61-n) on the battery modules 11-1 to 11-7 side, connectors 62 (62-1 to 62-n) on the control management module 12 side, and cables 63 (63-1 to 63-n) therebetween. The cables 63 (63-1 to 63-n) are two wires, one for a positive electrode and one for a negative electrode.

[0024] FIG. 4 is an explanatory diagram illustrating an outline of relay cables 70 (70-1 to 70-7) that connect the connectors 14-1 to 14-7 of the battery modules 11-1 to 11-7 and the connectors 56-1 to 56-7 of the control management module 12. As shown in FIG.

[0025] 4, the relay cables 70 (70-1 to 70-7) are made up of connectors 71 (71-1 to 71-7) on the battery modules 11-1 to 11-7 side, connectors 72 (72-1 to 72-7) on the control management module 12 side, and cables 73 (73-1 to 73-7) therebetween. The cables 73 (73-1 to 73-7) are made up of wiring whose number corresponds to the number of battery cells that make up the battery stack.

[0026] Here, an example of a battery module will be described with reference to Fig. 5. Fig. 5 is an explanatory diagram of an example of a battery module 11 (11-1 to 11-7). Note that the battery modules 11-1 to 11-7 are all configured in the same way.

[0027] As shown in FIG. 5, the battery module 11 (11-1 to 11-7) is provided with a battery stack consisting of battery cells 20-1, 20-2, ..., 20-n connected in series. For example, lithium iron phosphate ion batteries are used as the battery cells 20-1, 20-2, ..., 20-n. The lithium iron phosphate ion battery uses lithium iron phosphate in the positive electrode, and is characterized by its high safety as its crystal structure is not easily destroyed even if heat is generated inside the battery. The cell voltage of each battery cell 20-1, 20-2, ..., 20-n varies depending on the cell structure. In the case of a lithium ion battery, the cell voltage is 2V to 4V. In the case of a lithium iron phosphate ion battery, the cell voltage is, for example, about 3.3V.

[0028] The battery modules 11 (11-1 to 11-7) are provided with connectors 13 (13-1 to 13-7) and connectors 14 (14-1 to 14-7). The connectors 13 (13-1 to 13-7) are connectors for charging and discharging the battery modules 11. The connectors 14 (14-1 to 14-7) are connectors for monitoring the cell voltages of the battery cells 20-1, 20-2, ..., 20-n.

[0029] The configuration of the control management module will now be described with reference to Fig. 6. Fig. 6 is a block diagram showing the configuration of the control management module 12.

[0030] As shown in FIG. 6, the control management module 12 has a terminal block 31, a breaker 33, an HV (High-Voltage) board 40, and a BMS (Battery Management System) board 50 mounted thereon.

[0031] The terminal block 31 is a connector for connecting wiring from the power conditioner 1. The terminal block 31 is provided with a positive terminal 31a, a negative terminal 31b, and a ground terminal 31c. In this example, the ground terminal 31c is connected to the housing as a zero potential. Wires extending from the positive terminal 31a and the negative terminal 31b of the terminal block 31 form charge / discharge lines 35a and 35b. The breaker 33 is for protection when a large current flows.

[0032] The communication connector 32 is a connector for connecting a shielded wire for communication from the power conditioner 1. The communication connector 32 is connected to a communication connector 51 on the BMS board 50. Data from the power conditioner 1 is received via the communication connector 32 and sent to the microprocessor 54. In addition, data from the microprocessor 54 is sent to the power conditioner 1 via the communication connector 32.

[0033] The HV board 40 is a board for charging and discharging the battery modules 11-1 to 11-7. On the HV board 40, a relay 41, a current sensor 42, a communication connector 43, and connectors 45-1 to 45-7 are mounted.

[0034] The relay 41 serves as a switch for starting / stopping the operation of the storage battery unit 3. The current sensor 42 detects charging / discharging current to / from the battery modules 11-1 to 11-7. The communication connector 43 is connected to a communication connector 52 on the BMS board 50. The communication connector 43 transmits the detected current of the current sensor 42 to a microprocessor 54, for example.

[0035] The connectors 45-1 to 45-7 are terminals that connect to the connectors 13-1 to 13-7 on the battery modules 11-1 to 11-7 side, respectively. The connectors 13-1 to 13-7 on the battery modules 11-1 to 11-7 side are connectors for charging and discharging, and wiring from both ends of the battery cells 20-1, 20-2, ..., 20-n that constitute the battery stack is led out from the connectors 13-1 to 13-7. The connectors 45-1 to 45-7 are connected in series to obtain a desired charging and discharging voltage. The positive electrode of the connector 45-1 with the highest potential is connected to the charging and discharging line 35a, and the negative electrode of the connector 45-7 with the lowest potential is connected to the charging and discharging line 35b.

[0036] The BMS board 50 is a board for monitoring and controlling the states of the battery modules 11-1 to 11-7. The BMS board 50 is mounted with communication connectors 51 and 52, an AFE (Analog Front End) 53, a microprocessor 54, an optical isolation element 55, and connectors 56-1 to 56-7.

[0037] The communication connector 51 is connected to the communication connector 32, and transmits and receives data to and from the power conditioner 1. The communication connector 52 is connected to the communication connector 43, and transmits and receives data to and from the HV board 40.

[0038] AFE 53 detects the cell voltage of each of battery modules 11-1 to 11-7 and converts it into digital data.

[0039] The microprocessor 54 performs various controls based on data from the power conditioner 1, data from the HV board 40, data from the AFE 53, and the like.

[0040] The optical isolation element 55 is an element such as a photocoupler or a digital isolator, and connects the AFE 53 and the microprocessor 54. Since a high voltage is applied to the AFE 53, the optical isolation element 55 provides isolation between the AFE 53 and the microprocessor 54.

[0041] The connectors 56-1 to 56-7 are terminals that connect to the connectors 14-1 to 14-7 on the battery modules 11-1 to 11-7 side, respectively. The connectors 14 (14-1 to 14-7) are connectors for monitoring the cell voltages of the battery cells 20-1, 20-2, ..., 20-n. The connectors 56-1 to 56-7 transmit the cell voltages of the battery modules 11-1 to 11-7 to the BMS board 50 side, respectively.

[0042] Here, an overview of the AFE circuit element arranged on the BMS substrate will be described with reference to Fig. 7. Fig. 7 is a block diagram showing an overview of an AFE circuit element 530 arranged on the BMS substrate 50. In this embodiment, the function of the AFE 53 is realized by arranging AFE circuit elements 530 as shown in Fig. 7 in the number corresponding to the battery modules 11-1 to 11-7. Note that, here, only a part of the function of the AFE circuit element 530 that is necessary for explaining the present invention will be described. Note that the number of AFE circuit elements 530 is not limited to the number corresponding to the battery modules 11-1 to 11-7. For example, one AFE circuit element 530 may be connected to two battery modules.

[0043] 7, terminals A1, A2, ..., Am (m is any integer) are measurement terminals for detecting the cell voltage of the battery stack. When detecting the cell voltage of the battery stack, the battery cells are connected in the order from terminal A1 to terminal Am, from the electrode with the highest potential to the electrode with the lowest potential.

[0044] The resistor Ra and the switch circuit Sa between the terminals A1, A2, ..., Am are for balancing the battery cells. That is, when the switch circuit Sa is turned on, both poles of the battery cells are connected via the resistor Ra, and the energy in the battery cells is consumed by Joule heat. This causes the energy of the battery cells with a large charge to be consumed, and the charge amount of each battery cell can be equalized.

[0045] The terminals D1 and D2 are terminals for inputting and outputting data. Data is input and output between the AFE 53 and the microprocessor 54 via the terminals D1 and D2.

[0046] The terminal Vref is a terminal of a predetermined voltage. The terminal V- is a terminal of a reference voltage. The terminal Vtemp is a terminal for detecting temperature. When measuring temperature, a switch circuit Sb, a resistor Rb, and a thermistor Rt are connected in series between the terminal Vref and the terminal V-. The thermistor Rt is an example of a detection element that detects the state of the battery module. In this embodiment, the temperature of the battery module is detected using the thermistor Rt. The connection point between the resistor Rb and the thermistor Rt is connected to a terminal Vtemp for detecting temperature. The position where the switch circuit Sb is connected is not particularly limited. For example, the switch circuit Sb may be provided at any position in the path between the terminal Vref and the terminal V-. Also, for example, the switch circuit Sb may be built in as a function within the AFE circuit element 530.

[0047] <Embodiment> The power storage control system according to the present invention is applied to temperature measurement in the storage battery unit 3 configured as described above.

[0048] As shown in Fig. 7, the AFE circuit element 530 can detect temperature by attaching a thermistor Rt. For example, as shown in Fig. 8, thermistors Rt-1 to Rt-7 are provided in each of the battery modules 11-1 to 11-7. If the measured values ​​of the thermistors Rt-1 to Rt-7 are obtained from the terminals Vtemp of the AFE circuit elements 530-1 to 530-7, the temperatures of the battery modules 11-1 to 11-7 can be detected.

[0049] Here, an overview of the power storage control system will be described with reference to Fig. 8. Fig. 8 is a block diagram showing an overview of the power storage control system according to an embodiment of the present invention.

[0050] In the example shown in Fig. 8, AFE circuit elements 530-1 to 530-7 are arranged corresponding to battery modules 11-1 to 11-7. In Fig. 8, battery modules 11-1 to 11-7 are provided with a battery stack consisting of battery cells 20-1, 20-2, ..., 20-n. Both ends and intervals of each battery cell 20-1, 20-2, ..., 20-n are connected to terminals A1, A2, ..., Am of AFE circuit elements 530-1 to 530-7, respectively. Furthermore, each AFE circuit element 530-1 to 530-7 is connected in series.

[0051] The battery modules 11-1 to 11-7 are also provided with thermistors Rt-1 to Rt-7. One end of the resistors Rb-1 to Rb-7 is connected to the terminal Vref of the AFE circuit elements 530-1 to 530-7 via the switch circuits Sb-1 to Sb-7. One end of the thermistors Rt-1 to Rt-7 is connected to the terminal V- of the AFE circuit elements 530-1 to 530-7. The connection point between the resistors Rb-1 to Rb-7 and the thermistors Rt-1 to Rt-7 is connected to the terminal Vtemp of the AFE circuit elements 530-1 to 530-7.

[0052] Here, the relationship between temperature and the resistance value of the thermistor will be described with reference to Fig. 9. Fig. 9 is a graph showing the relationship between temperature and the resistance value of the thermistor.

[0053] As shown in Fig. 9, the resistance value of the thermistor decreases with temperature. Therefore, the higher the temperature, the larger the current flowing through the thermistors Rt-1 to Rt-7. The usage amounts of battery modules 11-1 to 11-7 differ depending on the current flowing through the thermistors Rt-1 to Rt-7. Therefore, if the temperatures detected based on the measurement values ​​of the thermistors Rt-1 to Rt-7 differ, the usage amounts of battery modules 11-1 to 11-7 will vary, causing an imbalance in the charge amounts of battery modules 11-1 to 11-7.

[0054] In the example of FIG. 8, it is considered that the temperature of the battery modules 11-1 to 11-7 increases in ascending order of placement, and the current flowing through the thermistors Rt-1 to Rt-7 increases. In other words, since warm air flows upward, in the example of FIG. 8, it is considered that the battery modules placed at the top will have a higher temperature than the battery modules placed below them. For this reason, it is considered that the current flowing through the thermistor Rt-1 in the battery module 11-1 placed at the top among the thermistors Rt-1 to Rt-7 placed in the battery modules 11-1 to 11-7 will be the largest, and the currents of the thermistors in the battery modules placed below will be smaller, and the current flowing through the thermistor Rt-7 in the battery module 11-7 placed at the bottom will be the smallest. It is therefore considered that the charge amount decreases in the ascending order of placement among the battery modules 11-1 to 11-7.

[0055] Therefore, in this embodiment, the temperature is used as a parameter to set the time for which the switch circuits Sb-1 to Sb-7 are turned on, thereby balancing the charge amounts of the battery modules 11-1 to 11-7.

[0056] The current flowing through the thermistors Rt-1 to Rt-7 is determined by the voltage between terminal Vref and terminal V-, the resistance values ​​of resistors Rb-1 to Rb-7, and the resistance values ​​of the thermistors Rt-1 to Rt-7. The voltage between terminal Vref and terminal V- and the resistance values ​​of resistors Rb-1 to Rb-7 are known. The resistance values ​​of the thermistors Rt-1 to Rt-7 can be found from the graph shown in FIG. 9 using temperature as a parameter. Therefore, by detecting the temperature of each of the battery modules 11-1 to 11-7 based on the measurement values ​​of the thermistors Rt-1 to Rt-7, the resistance value of each of the thermistors Rt-1 to Rt-7 can be obtained from the relationship between temperature and resistance value as shown in the graph of Fig. 9. Then, the current flowing through the thermistors Rt-1 to Rt-7 can be obtained. Once the current flowing through the thermistors Rt-1 to Rt-7 is determined, the product of the current flowing through the thermistors Rt-1 to Rt-7 and the on-time of the switch circuits Sb-1 to Sb-7 becomes the discharge amount of the battery modules 11-1 to 11-7, and the time for which the switch circuits Sb-1 to Sb-7 are turned on can be determined so that this discharge amount is uniform.

[0057] The temperature of each of the battery modules 11-1 to 11-7 can be obtained, for example, from the measurement values ​​of thermistors Rt-1 to Rt-7 immediately after switching circuits Sb-1 to Sb-7 are turned on. Also, the temperature of each of the battery modules 11-1 to 11-7 can be obtained, for example, from the previous measurement values ​​of thermistors Rt-1 to Rt-7.

[0058] In order to obtain the current flowing through each of the thermistors Rt-1 to Rt-7 from the temperature of each of the battery modules 11-1 to 11-7, a table that associates the temperature of the battery modules with the resistance value at each temperature (hereinafter also referred to as a "resistance value acquisition table") may be created in advance. The resistance value acquisition table can be created, for example, from a graph such as that shown in FIG. In order to determine the control time of each of the switch circuits Sb-1 to Sb-7 from the temperature of each of the battery modules 11-1 to 11-7, a table that associates the temperature of the battery modules with the control time of the switch circuit at each temperature (hereinafter also referred to as a "control time determination table") may be created in advance. By using the control time determination table, it is also possible to directly determine the control time of each of the switch circuits Sb-1 to Sb-7 from the temperature of each of the battery modules 11-1 to 11-7.

[0059] Here, the switch control time of the power storage control system will be described with reference to Fig. 10. Fig. 10 is an explanatory diagram of the switch control time of the power storage control system according to the embodiment of the present invention.

[0060] As shown in FIG. 10, the temperature TMP1 of the battery module 11-1 arranged at the top is the highest, followed by the battery modules arranged at the bottom, with the temperature TMP7 of the battery module 11-7 arranged at the bottom being the lowest. In this case, the time for turning on each of the switch circuits Sb-1 to Sb-7 is determined according to each of the temperatures TMP1 to TMP7 so that the discharge amounts of each of the battery modules 11-1 to 11-7 are uniform. As a result, as shown in FIG. 10, the time for turning on the switch circuits Sb-1 to Sb-7 is set so that the switch-on time T1 of the thermistor Rt-1 is the shortest, followed by the switch-on times T1 to T7 of the thermistors Rt-1 to Rt-7 in that order, with the switch-on time T7 of the thermistor Rt-7 being the longest. This allows the charge amounts of the battery modules 11-1 to 11-7 to be kept uniform.

[0061] Here, a flow of processing in the power storage control system according to the present invention will be described with reference to Fig. 11. Fig. 11 is a flowchart used to explain the power storage control system according to the embodiment of the present invention.

[0062] As shown in FIG. 11, first, the microprocessor 54 controls the switch circuits Sb-1 to Sb-7 to be ON (step S101).

[0063] The microprocessor 54 detects the temperature of each of the battery modules 11-1 to 11-7 from the measurement value of each of the thermistors Rt-1 to Rt-7 immediately after turning on each of the switch circuits Sb-1 to Sb-7 (step S102). The measurement value of each of the thermistors Rt-1 to Rt-7 can be obtained from the voltage of the terminal Vtemp of the AFE circuit elements 530-1 to 530-7.

[0064] The microprocessor 54 checks parameter information corresponding to each detected temperature (step S103). For example, the microprocessor 54 checks a resistance value acquisition table and a control time determination table as parameter information.

[0065] The microprocessor 54 determines the control time for each of the switch circuits Sb-1 to Sb-7 from the parameter information (step S104). When using the resistance value acquisition table, the microprocessor 54 first refers to the resistance value acquisition table to acquire the resistance value of each of the thermistors Rt-1 to Rt-7 corresponding to the temperature detected in step S102. Next, the microprocessor 54 obtains the current flowing through each of the thermistors Rt-1 to Rt-7 from the acquired resistance value, the voltage between the terminal Vref and the terminal V-, and the resistance values ​​of the resistors Rb-1 to Rb-7. Then, the microprocessor 54 determines the control time of the switch circuits Sb-1 to Sb-7 so that the discharge amounts of each of the battery modules 11-1 to 11-7 are the same. When the control time determination table is used, the microprocessor 54 refers to the control time determination table, acquires the control time corresponding to the temperature detected in step S102, and determines the control time for each of the switch circuits Sb-1 to Sb-7.

[0066] The microprocessor 54 determines whether or not the control time determined in step S104 has elapsed for each of the switch circuits Sb-1 to Sb-7 (step S105). If the control time has not elapsed (step S105 / No), the microprocessor 54 repeats the process of step S105. On the other hand, if there is a switch circuit for which the control time has elapsed (step S105 / Yes), the microprocessor 54 advances the process to step S106.

[0067] When the process proceeds to step S106, the microprocessor 54 turns off the corresponding switch circuit (step S106). When any switch circuit that is turned on remains, the microprocessor 54 repeats the process from step S105 for the remaining switch circuits. When all switch circuits to be controlled are turned off, the microprocessor 54 ends the process.

[0068] As described above, in the power storage control system according to the embodiment of the present invention, the microprocessor 54 (sensor setting unit) detects the temperature of each of the battery modules 11-1 to 11-7. The microprocessor 54 determines the control time of each of the thermistors Rt-1 to Rt-7 (detection elements that detect the state of the battery modules) according to the detected temperature of each of the battery modules 11-1 to 11-7.

[0069] With this configuration, in the energy storage control system according to the embodiment of the present invention, the microprocessor 54 controls the on / off of each of the switch circuits Sb-1 to Sb-7 in accordance with the determined control time, thereby balancing the charge amounts of the battery modules 11-1 to 11-7. Therefore, the power storage control system according to the embodiment of the present invention makes it possible to suppress imbalance in the charge amounts of the storage batteries caused by temperature.

[0070] In the above description, thermistors Rt-1 to Rt-7 are used as detection elements for detecting the states of battery modules 11-1 to 11-7. However, the detection elements are not limited to detection elements for detecting temperature, and any detection element whose resistance value changes with temperature may be used.

[0071] In the above-described embodiment, the power supply system may be configured as shown in Fig. 12. Fig. 12 is a block diagram showing an outline of another configuration example of the power supply system according to the present invention. In a power supply system 10A in Fig. 12, a solar panel 2, a storage battery unit 3, and an EV stand 4 are each independently connected to power conditioners 1A, 1B, and 1C, respectively. In FIG. 12, each of power conditioners 1A, 1B, and 1C supplies or demands power (electrical energy) between a solar panel 2, a storage battery unit 3, and an EV stand 4, respectively, via a distribution board 6. The configuration and operation of the storage battery unit 3 in FIG. 12 are similar to those of the storage battery unit 3 in the present embodiment already described.

[0072] In the above-described embodiment, the power supply system may be configured as shown in Fig. 13. Fig. 13 is a block diagram showing an outline of another configuration example of the power supply system according to the present invention. In a power supply system 10B in Fig. 13, each of the solar panel 2 and the storage battery unit 3 is connected to a power conditioner 1D, and the EV stand 4 is connected to a power conditioner 1C. In FIG. 13, each of power conditioners 1C and 1D supplies or demands power (electrical energy) between a solar panel 2, a storage battery unit 3, and an EV stand 4, via a distribution board 6, respectively. The configuration and operation of the storage battery unit 3 in FIG. 13 are similar to those of the storage battery unit 3 in the present embodiment already described.

[0073] In the above description, the terminals Vtemp of the AFE circuit elements 530-1 to 530-7 are used to convert the detected voltage of the thermistor Rt into digital data and supply it to the microprocessor 54, but the configuration for acquiring the detected voltage of thermistor Rt is not limited to this example. For example, configurations shown in Figures 14A to 14D are examples of other configurations for acquiring the detected voltage of thermistor Rt.

[0074] 14A to 14D are diagrams showing other configuration examples for processing the detected voltage of the thermistor Rt according to the present invention. 14A, the detected voltage of the thermistor Rt is converted into digital data by the AFE 53 and supplied to the microprocessor 54. This configuration is similar to the configuration in which the detected voltage of the thermistor Rt is obtained from the terminals Vtemp of the AFE circuit elements 530-1 to 530-7. In Fig. 14B, the detection voltage of the thermistor Rt is directly input to the microprocessor 54. If the microprocessor 54 has an analog input port, the detection signal of the thermistor Rt can be directly input to the microprocessor 54 in this manner to detect temperature. In FIG. 14C, the detection signal of the thermistor Rt is converted into digital data by an A / D converter 201 and input to the microprocessor 54. In FIG. 14D, the detection signal of the thermistor Rt is converted into digital data by an A / D converter 201, and is input to the microprocessor 54 via an isolation element 202 such as a photocoupler or digital isolator.

[0075] The storage control system in the above-described embodiment may be realized in whole or in part by a computer. In that case, a program for realizing this function may be recorded in a computer-readable recording medium, and the program recorded in the recording medium may be read into a computer system and executed to realize the function. The term "computer system" as used herein includes hardware such as an OS and peripheral devices. The term "computer-readable recording medium" refers to a portable medium such as a flexible disk, an optical magnetic disk, a ROM, a CD-ROM, and a storage device such as a hard disk built into a computer system. The term "computer-readable recording medium" may also include a medium that dynamically holds a program for a short period of time, such as a communication line when a program is transmitted via a network such as the Internet or a communication line such as a telephone line, and a medium that holds a program for a certain period of time, such as a volatile memory inside a computer system that is a server or client in that case. The above-described program may be a program for realizing a part of the above-described function, or may be a program that can realize the above-described function in combination with a program already recorded in the computer system, or may be a program that is realized using a programmable logic device such as an FPGA.

[0076] Although an embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and designs that do not deviate from the gist of the present invention are also included. [Explanation of symbols]

[0077] 3...storage battery unit, 11 (11-1 to 11-7)...battery module, 12...control management module, 53...AFE, 54...microprocessor, Rt-1 to Rt-7...thermistor, 530-1 to 530-7...AFE circuit element

Claims

1. A power storage control method for controlling charging and discharging of a battery module constituting a storage battery used in a storage battery unit, detecting a temperature of the battery module; setting an on-time of a detection element for detecting a state of the battery module in accordance with a temperature of the battery module; Including, The storage battery includes a plurality of battery modules connected in series; the detection element is provided for each of the battery modules, The on-time is set so that the amount of discharge consumed by each detection element is uniform. Energy storage control method.

2. The on-time is set in response to a change in the resistance value of the detection element depending on the temperature. The power storage control method according to claim 1 .

3. The detection element is a thermistor. The power storage control method according to claim 1 or 2.

4. The on-time of the detection element is set using a switch circuit. The power storage control method according to any one of claims 1 to 3.

5. A power storage control system that controls charging and discharging of a battery module that constitutes a storage battery used in a storage battery unit, A detection element for detecting a state of the battery module; a sensor setting unit that sets an on-time of the detection element in response to a temperature of the battery module; Equipped with The storage battery includes a plurality of battery modules connected in series; the detection element is provided for each of the battery modules, The on-time is set so that the amount of discharge consumed by each detection element is uniform. Energy storage control system.

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