Electricity storage device

Abstract

A power storage device (20) is provided with: a unit (31); a switching circuit (50) located on a current path of the cell (31); and a control device (100). The switching circuit (50) is a circuit that switches the output impedance (Z) of the power storage device (20), and the control device (100) uses the switching circuit (50) to switch the output impedance of the power storage device (20).

Description

Technical Field

[0001] The present invention relates to a technology for controlling the output impedance of an electric storage device. Background Art

[0002] The power storage device mounted on a car or the like has a current cutoff device such as a FET. When an abnormality such as overdischarge or overcharge is detected, the current is cutoff by opening the current cutoff device to protect the power storage device. Patent Document 1 discloses this technology.

[0003] Prior Art Literature

[0004] Patent Literature

[0005] Patent Document 1: WO2019 / 111872 Summary of the invention

[0006] Problems to be solved by the invention

[0007] The output performance required of a power storage device for a vehicle varies depending on the purpose and usage conditions. For example, when the vehicle is parked, only a small current can be output, but when the vehicle is driving or other than parking, a larger current needs to be charged and discharged than when the vehicle is parked. In the past, the output impedance of the power storage device was fixed, so the output performance could not be changed. In addition, the same problem also exists in power storage devices other than those for vehicles.

[0008] An object of the present invention is to provide a power storage device with a function of switching output impedance.

[0009] Means for solving problems

[0010] The power storage device comprises: a unit; a switching circuit located on a current path of the unit; and a control device. The switching circuit is a circuit for switching the output impedance of the power storage device, and the control device uses the switching circuit to switch the output impedance of the power storage device according to given conditions. The given conditions are, for example, the purpose, usage status, actual capacity, internal resistance, degradation state, etc. of the power storage device.

[0011] Effects of the Invention

[0012] In the power storage device, the output performance of the power storage device can be changed by switching the output impedance. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a side view of the car.

[0014] Figure 2 It is a three-dimensional diagram of a battery.

[0015] Figure 3 It is an exploded perspective view of a battery.

[0016] Figure 4 is a block diagram showing the electrical structure of a battery.

[0017] Figure 5 It is a circuit diagram of a switching circuit.

[0018] Figure 6 It is a diagram showing the details of the switching circuit.

[0019] Figure 7 It is a schematic diagram of a battery.

[0020] Figure 8 This is a graph summarizing the output impedance of batteries and their uses.

[0021] Fig. 9 This is a flow chart of the switching control of the output impedance.

[0022] Fig.10 This is a flow chart of the switching control of the output impedance.

[0023] Fig.11 It is a circuit diagram of a switching circuit. DETAILED DESCRIPTION

[0024] (Overview of this embodiment)

[0025] (1) An electric storage device according to one embodiment of the present invention comprises: a unit; a switching circuit located on a current path of the unit; and a control device. The switching circuit is a circuit for switching the output impedance of the electric storage device, and the control device uses the switching circuit to switch the output impedance of the electric storage device according to given conditions. The given conditions may be, for example, the purpose, usage status, actual capacity, etc. of the electric storage device.

[0026] According to an embodiment of the present invention, the power storage device can switch the output impedance according to a given condition to achieve output performance suitable for a given condition. For example, in the case of a small current application, the current of the power storage device can be reduced by switching the output impedance to a large one. In the case of a large current application, the current can flow easily by switching the output impedance to a small one, and it is easy to ensure a sufficient current.

[0027] (2) In the power storage device described in (1) above, the control device may acquire information on the purpose of the power storage device or information on a usage status of the power storage device through communication with a vehicle, and switch the output impedance of the power storage device based on the acquired information.

[0028] This structure switches the output impedance according to the purpose and use status of the power storage device, so that the power storage device can exert output performance according to the purpose and use status. In addition, it has the advantage of being able to change the output performance every time the use status of the power storage device mounted on the vehicle changes.

[0029] (3) In the power storage device described in (1) above, the control device may acquire information on the type of the vehicle through communication with the vehicle, and may switch the output impedance of the power storage device based on the acquired information.

[0030] The maximum current required for the power storage device may differ depending on the type of vehicle. For example, a large vehicle requires a larger maximum current than a light vehicle. This structure can supply a maximum current corresponding to the type of vehicle from the power storage device to the vehicle. Therefore, there is an advantage that the power storage device can be used universally in vehicles of different types. The type of vehicle is not limited to light vehicles or large vehicles, as long as it distinguishes vehicles with different maximum current requirements. It can be any type.

[0031] (4) In the power storage device described in (1) above, the control device may include a storage unit storing information on the actual capacity of the power storage device or information related to the purpose of use, and the output impedance of the power storage device may be switched based on the information on the actual capacity of the power storage device or the purpose of use stored in the storage unit.

[0032] This structure can switch the output impedance of the power storage device according to the actual capacity and purpose of the power storage device. Therefore, the power storage device can exert output performance corresponding to the actual capacity and purpose. This structure has the following advantages: even if there is no communication function with a higher-level device such as a vehicle, the power storage device can autonomously change the output impedance.

[0033] (5) In the power storage device described in (1) above, the control device may switch the output impedance of the power storage device according to the internal resistance or degradation state of the cell.

[0034] According to this structure, by switching the output impedance according to the internal resistance of the cell, it is easy to keep the total resistance of the power storage device constant regardless of the increase in internal resistance due to the passage of time after manufacturing and long-term use. Therefore, it is possible to suppress heat generation while maintaining the power supply capacity to the load. The structure that switches the output impedance of the power storage device according to the degradation state also has the same effect.

[0035] (6) In the power storage device described in any one of (1) to (5) above, the switching circuit may be a plurality of current-carrying circuits connected in parallel, the plurality of current-carrying circuits having different line resistances, and the control device switches the output impedance of the power storage device by selecting or combining the current-carrying circuits.

[0036] This structure can switch the output impedance of the power storage device by selecting or combining the energized circuits. In addition, by disconnecting all the energized circuits, the current can be cut off, so it can also be used as a protection device for the power storage device.

[0037] <Implementation Method 1>

[0038] 1. Battery Description

[0039] Figure 1 is the side view of the car, Figure 2 This is a three-dimensional diagram of a battery. Figure 3 This is an exploded perspective view of the battery. Figure 4 is a block diagram showing the electrical structure of a battery. Figure 1 In FIG. 1 , only the automobile 1 and the battery 20 are shown, and other components constituting the automobile are omitted.

[0040] like Figure 1 As shown, a car (an example of a vehicle) 1 includes a battery 20 as a power storage device. Figure 2 As shown, the storage battery 20 has a block-shaped battery case 21 , and a battery pack 30 composed of a plurality of cells 31 , a circuit board 120 , and the like are accommodated in the battery case 21 .

[0041] In the following description, when referring to Figure 2 as well as Figure 3 In the case of the battery case 21 being placed horizontally without tilting relative to the installation surface, the up-down direction of the battery case 21 is set as the Y direction, the direction along the long side of the battery case 21 is set as the X direction, and the depth direction of the battery case 21 is set as the Z direction for description.

[0042] like Figure 3 As shown, the battery case 21 is configured to include: a box-shaped case body 23 that opens upward; a positioning member 24 that positions a plurality of cells 31; a middle cover 25 that is mounted on the upper portion of the case body 23; and an upper cover 29 that is mounted on the upper portion of the middle cover 25. In the case body 23, a plurality of cell chambers 23A that individually accommodate each cell 31 are arranged in the X direction.

[0043] like Figure 3As shown, the positioning member 24 has a plurality of bus bars 24A disposed on the upper surface thereof, and the positioning member 24 is disposed above the plurality of cells 31 disposed in the housing body 23. Therefore, the plurality of cells 31 are positioned and connected in series via the plurality of bus bars 24A.

[0044] like Figure 3 As shown, the middle cover 25 is generally rectangular in plan view, and a pair of external terminals 22P and 22N connected to the wiring harness terminals (not shown) are provided at both ends in the X direction. The pair of external terminals 22P and 22N are made of metal such as lead alloy, for example, and the external terminal 22P is used for the positive electrode, and the external terminal 22N is used for the negative electrode.

[0045] like Figure 3 As shown, a circuit board 120 is disposed on the upper surface of the middle cover 25 , and the upper surface thereof is closed by the upper cover 29 .

[0046] Figure 4 2 is a block diagram showing the electrical configuration of the storage battery 20 . The storage battery 20 includes a battery pack 30 , a voltage measuring unit 41 , a current measuring unit 43 , a temperature sensor 45 , a switching circuit 50 , and a management device 100 .

[0047] The battery pack 30 includes, for example, four cells 31 (see Figure 2 ), and four are connected in series. The unit is not limited to a prismatic unit, and may be a cylindrical unit or a bag-type unit having a laminated film shell. The unit 31 is, for example, a lithium-ion secondary battery unit.

[0048] The battery pack 30 , the current measuring unit 43 , and the switching circuit 50 are connected in series via the power line 35P and the power line 35N.

[0049] like Figure 4 As shown, the power line 35P connects the positive external terminal 22P and the positive electrode of the battery pack 30. The power line 35N connects the negative external terminal 22N and the negative electrode of the battery pack 30. The external terminals 22P and 22N are terminals for connection with the automobile 10, and can be electrically connected to the auxiliary machine 15 and the vehicle ECU (Electronic Control Unit) 16 on the vehicle via the external terminals 22P and 22N.

[0050] The voltage measuring unit 41 can measure the cell voltage Vs of each of the cells 31A to 31D and the total voltage of the battery pack 30 .

[0051] The current measuring unit 43 is provided on the negative power line 35N. The current measuring unit 43 may be a shunt resistor. The resistance-type current measuring unit 43 can measure the current I of the battery pack 30 based on the voltage across the current measuring unit 43. Alternatively, the current measuring unit 43 may be a magnetic sensor.

[0052] The temperature sensor 45 is mounted on the battery pack 30 and detects the temperature of the battery pack 30 or its surroundings.

[0053] The switching circuit 50 is mounted on the circuit board 120 and provided on the positive power line 35P. The switching circuit 50 is a circuit for switching the output impedance Z of the storage battery 20. The switching circuit 50 will be described in detail later.

[0054] like Figure 4 As shown, the management device 100 is mounted on a circuit board 120 and includes a CPU 101, a storage unit 103, and a communication unit 105. The management device 100 corresponds to the "control device" of the present invention. The storage unit 103 stores information for specifying the use of the storage battery 50. For example, the information is the part number of the storage battery 50.

[0055] The management device 100 monitors the state of the storage battery 20 based on the outputs of the voltage measuring unit 41, the current measuring unit 43, and the temperature sensor 45. That is, the management device 100 monitors the cell voltage Vs of each cell 31, the temperature of the battery pack 30, the current I, and the total voltage V.

[0056] The communication unit 105 is used for communication connection with the vehicle ECU 16. The management device 100 can be connected to the vehicle ECU 16 via the communication unit 105, the connector 106, and the communication line 107.

[0057] The storage unit 103 stores a monitoring program for the storage battery 20 , a switching program for the output impedance Z, and data required to execute these programs. The storage unit 103 further stores information (for example, a part number) for specifying the use of the storage battery 20 .

[0058] The vehicle ECU 16 can identify the use of the battery 20 by reading information for identifying the use (for example, the part number) from the battery 20 when communication with the battery 20 is started. For example, if a reference table is provided that stores the part number and the use in association with each other, the use can be identified based on the part number. The use of the battery 20 is for auxiliary equipment, for engine starting, and the like.

[0059] The program may be stored in a recording medium such as a CD-ROM and used, transferred, loaned, etc. The program may also be distributed using a telecommunication line.

[0060] 2. Output impedance switching control

[0061] Figure 52 is a circuit diagram of the switching circuit 50. The switching circuit 50 is a circuit for switching the output impedance Z of the storage battery 20. In this embodiment, the switching circuit 50 has three energizing circuits 51A to 51C connected in parallel.

[0062] The first to third power-carrying circuits 51A to 51C respectively have switch circuits 53A to 53C. By turning off the switch circuits 53A to 53C, each power-carrying circuit 51A to 51C can be cut off. By turning on the switch circuits 53A to 53C, each power-carrying circuit 51A to 51C can be turned on to allow current to flow.

[0063] For example, Figure 6 As shown, the switch circuits 53A to 53C can be formed by two FETs (field effect transistors) 54 and 55 connected back to back.

[0064] like Figure 5 As shown, the first power supply circuit 51A is only a switch circuit 53A and does not include a current limiting element. The second power supply circuit 51B and the third power supply circuit 51C include current limiting elements 57 and 58 in addition to the switch circuits 53B and 53C.

[0065] The current limiting element 57 and the current limiting element 58 are resistors. The two current limiting elements 57 and 58 have different resistance values, and the resistance value of the current limiting element 58 of the third current supply circuit 51C is larger than that of the current limiting element 57 of the second current supply circuit 51B.

[0066] That is, in the three power circuits 51A to 51B, the resistance values ​​of the lines LA to LC connecting the positive electrode of the battery pack 30 to the external terminal 22P of the positive electrode are different. Regarding the resistance values ​​of the lines LA to LC, the resistance values ​​increase in the order of the first power circuit 51A, the second power circuit 51B, and the third power circuit 51C, and the resistance value of the line LC of the third power circuit 51C is the largest. The resistance value of the lines LA to LC is the sum of the resistance of the lines themselves and the resistance of the current limiting element provided in the lines.

[0067] (Relationship between line resistance)

[0068] RA<RB<RC

[0069] RA: resistance value of line LA of first current circuit 51A

[0070] RB: resistance value of line LB of second current circuit 51B

[0071] RC: Resistance value of line LC of the third current supply circuit 51C

[0072] As described above, the output impedance Z of the battery 20 can be switched by selectively or in combination using the first to third energizing circuits 51A to 51C.

[0073] Figure 7 is a simplified equivalent circuit of the battery 20, where VC represents the internal electromotive force of the battery pack 30, and Z represents the output impedance. The output impedance Z is the value when the battery 20 is viewed from the output terminals 22P and 22N (at Figure 7 The impedance of the battery 20 when viewed from direction A.

[0074] For example, Figure 8 As shown, when the first energizing circuit 51A having a small line resistance is selected, the output impedance Z of the battery 20 is small.

[0075] On the other hand, when the second energizing circuit 51B having a medium line resistance is selected, the output impedance Z of the battery 20 is medium, and when the third energizing circuit 51C having a large line resistance is selected, the output impedance Z of the battery 20 is large.

[0076] When the output impedance Z is small, the current flows easily, and large current charging and discharging can be performed, so it is suitable for large current applications. When the output impedance Z is large, the current is limited, so it is suitable for small current applications.

[0077] Fig. 9 4 is a flowchart of the switching control of the output impedance Z. The switching control of the output impedance Z is composed of four steps S10 to S40 and is executed when, for example, the communication with the vehicle ECU 16 is started as a trigger when the battery 20 is mounted on the vehicle.

[0078] When the switching control of the output impedance Z starts, the management device 100 first accesses the vehicle ECU 16 to obtain information on the use of the battery 20 from the vehicle EUC 16. The use of the battery 20 is, for example, for auxiliary equipment, for engine starting, and the like.

[0079] Engine starting is a high current application because it discharges a starting current of several hundred A to 1000 A. Auxiliary machines are charged and discharged at several tens of A to 500 A, so they are medium current applications.

[0080] When the battery 20 is used for auxiliary machinery (medium current), the management device 100 disconnects the first power circuit 51A and controls the second power circuit 51B and the third power circuit 51C to be turned on. Thus, the output impedance Z of the battery 20 for auxiliary machinery can be switched to "medium" (S30).

[0081] When the battery 20 is used for engine starting (for high current), the management device 100 controls all the first to third energizing circuits 51A to 51C to be turned on, thereby switching the output impedance Z of the battery 20 for engine starting to “small” ( S40 ).

[0082] 4. Effect

[0083] According to this configuration, the output impedance Z of the battery 20 can be switched according to the application of the battery 20. Therefore, the battery 20 can exhibit output performance according to the application.

[0084] For example, for engine starting, by switching the output impedance Z to "small", current flows more easily than when the output impedance Z is "medium" or "large". Therefore, sufficient current required for starting the engine can be discharged, and the startability of the engine can be ensured.

[0085] For auxiliary machines, by switching the output impedance Z to “medium”, current is less likely to flow than when the output impedance Z is “small”. Therefore, Joule heat can be reduced, and heat generation of the battery 20 can be suppressed.

[0086] When a short-circuit current exceeding a threshold value flows in a generally used storage battery due to an external short circuit or the like, the storage battery 20 is protected by cutting off the current using a relay or the like.

[0087] However, in the state of cutting off the current, the storage battery 20 cannot be used, and in order to release the cutting off of the current, a special operation is sometimes required and time-consuming. In addition, since the battery pack 30 is cut off from the external terminal 22, there is also a problem that the voltage of the storage battery 20 cannot be measured.

[0088] In this structure, for the auxiliary machine, by switching the output impedance Z to "medium", the current is less likely to flow compared to the case where the output impedance Z is controlled to "small". Therefore, even if an external short circuit occurs, the short circuit current is less likely to exceed the threshold, so the chance of cutting off the current can be reduced. Therefore, the above-mentioned problem can be solved.

[0089] The storage battery 20 described in this embodiment can also cut off the current exceeding the threshold value by controlling all the energizing circuits 51A to 51C to be OFF.

[0090] <Implementation Method 2>

[0091] The second embodiment differs from the first embodiment in the switching control of the output impedance Z. Fig.10 This is a flowchart of the switching control of the output impedance Z in the second embodiment.

[0092] The switching control of the output impedance Z is composed of four steps S15 to S45, and is executed at a predetermined cycle after the battery 20 is mounted on the vehicle, for example. In this example, it is assumed that the battery 20 is for auxiliary equipment.

[0093] When the switching control of the output impedance Z starts, the management device 100 first accesses the vehicle ECU 16 to obtain information on the state of the automobile 10 from the vehicle EUC 16. Specifically, information on whether the automobile 10 is parked or in another state is obtained.

[0094] When the vehicle 10 equipped with the battery 20 is parked (when the battery 20 is used for the parked vehicle 10 ), the management device 100 controls the first power circuit 51A and the second power circuit 51B to be turned off and the third power circuit 51C to be turned on.

[0095] Thus, when the automobile 10 equipped with the battery 20 is parked, the output impedance Z of the battery 20 can be switched to “large” ( S35 ).

[0096] When the vehicle 10 equipped with the battery 20 is not parked (when the battery 20 is used for the vehicle in motion), the management device 100 disconnects the first power circuit 51A and controls the second power circuit 51B and the third power circuit 51C to be turned on.

[0097] Thus, when the automobile 10 equipped with the battery 20 is in a state other than parked, the output impedance Z of the battery 20 can be switched to “medium” ( S45 ).

[0098] In this configuration, the output impedance Z of the battery 20 can be switched according to the usage status of the battery 20. Therefore, the battery 20 can exhibit output performance according to the usage status.

[0099] Specifically, when the vehicle 10 is parked and the charging and discharging is less frequent, the output impedance is switched to "large" to suppress the output current of the battery 20. In addition, when the vehicle is used for discharging to an auxiliary machine or charging from an AC generator, the output impedance is switched to "medium" to charge and discharge the current suitable for discharging or charging the auxiliary machine.

[0100] <Implementation Method 3>

[0101] In the first embodiment, information on the use of battery 20 is acquired by communicating with vehicle ECU 16 to switch output impedance Z of battery 20. In the second embodiment, information on the use status of battery 20 is acquired by communicating with vehicle ECU 16 to switch output impedance Z of battery 20.

[0102] In implementation mode 3, Fig.11 As shown, in the production process of the storage battery 20, the data of the actual capacity [Ah] of the storage battery 20 is written and stored in the storage unit 103. In this case, the storage unit 103 is preferably non-volatile. The actual capacity is the amount of electricity that can be taken out from the storage battery 20, also known as the full charge capacity [Ah].

[0103] After being activated, the control device 100 reads data of the actual capacity [Ah] from the storage unit 103 and switches the output impedance Z of the battery 20 .

[0104] For example, the output impedance Z of the small capacity battery 20 is switched to “large”, and the output impedance Z of the medium capacity battery 20 is switched to “medium”. Also, the output impedance Z of the large capacity battery 20 is switched to “small”.

[0105] In this structure, the output impedance Z of the battery 20 can be switched according to the actual capacity. Therefore, the battery 20 can exert output performance corresponding to the actual capacity. This structure has the following advantages: the battery 20 can autonomously change the output impedance Z even if there is no communication function with a host device such as a car.

[0106] <Other Implementation Methods>

[0107] The present invention is not limited to the embodiments described in the above description and drawings, and for example, the following embodiments are also included in the technical scope of the present invention.

[0108] (1) The cell (electricity storage cell capable of repeated charge and discharge) 31 is not limited to a lithium ion secondary battery cell, but may be another non-aqueous electrolyte secondary battery cell. A capacitor may be used instead of the secondary battery cell 31 .

[0109] (2) In the above-mentioned embodiments 1 to 3, the battery 20 for vehicles is described. In the case of the form of the third embodiment, the battery 20 is not limited to vehicles, and can also be used for other purposes. For example, it can also be used for stationary purposes such as a power storage device for absorbing fluctuations in a distributed power generation system and a UPS (uninterruptible power supply).

[0110] (3) In the first embodiment, the vehicle ECU 16 determines the purpose of the battery 20 based on the part number of the battery 20. The present invention is not limited to this, and the purpose of the battery 20 may be determined based on the actual capacity of the battery 20. That is, as exemplified in the third embodiment, if the data of the actual capacity of the battery 20 is written to the storage unit 103 during the manufacturing process, the vehicle ECU 16 can also determine the purpose of the battery 20 by reading the data of the actual capacity from the battery 20 when communication starts.

[0111] (4) In the first embodiment, the vehicle ECU 16 determines the purpose of the battery 20. However, if the vehicle information (such as a vehicle code for identifying the vehicle) is acquired through communication with the vehicle, the battery 20 can also determine the purpose of the battery 20. For example, if a reference table that associates the vehicle information with the purpose of the battery is stored in the storage unit 103 of the battery 20, the vehicle information can be sent from the vehicle ECU 16 to the control device 100, so that the control device 100 can determine the purpose of the battery 20.

[0112] (5) In the second embodiment, when the battery 20 is used in the parked car 10, the output impedance Z of the battery 20 is switched to "large". In addition, for example, before the battery 20 is mounted on the car 10 (battery transportation, etc.) or when the battery 20 is removed from the car 10, the output impedance Z of the battery 20 may be switched to "large". The attachment or removal from the car 10 can be determined based on the communication state with the vehicle ECU 16. For example, if no communication with the vehicle ECU 16 is performed even once, it can be determined that the battery 20 is before being mounted on the car 10. If there is no communication with the vehicle ECU 16 for a predetermined time or longer after the communication with the vehicle ECU 16 is started, it can be determined that the battery 20 is removed from the car 10.

[0113] (6) In the above-mentioned first to third embodiments, a plurality of energized circuits 51A to 51C connected in parallel are shown as an example of the switching circuit 50 for switching the output impedance Z. The switching circuit 50 is not limited to the circuit configuration of the embodiment as long as it can switch the output impedance Z of the battery 20. For example, a circuit using a variable resistor may be used.

[0114] (7) In the above-mentioned first to third embodiments, the switch circuits 53A to 53C are constituted by two FETs. The switch circuits 53A to 53C may be constituted by a single switch or other configurations as long as they can switch current.

[0115] (8) In the third embodiment, the data of the actual capacity [Ah] of the storage battery 20 is written and stored in the storage unit 103 during the production process of the storage battery 20. Furthermore, when the control device 100 is activated, the data of the actual capacity is read from the storage unit 103 and the output impedance Z is switched. In addition to the data of the actual capacity, data of the use of the storage battery 20 may be written and stored in the storage unit 103 during the production process. Furthermore, when the control device 100 is activated, the data of the use may be read from the storage unit 103 and the output impedance Z may be switched.

[0116] (9) In the above-mentioned embodiments 1 to 3, the switching circuit 51 is composed of three power-carrying circuits 51A to 51C connected in parallel. In addition to the purpose of switching the output impedance Z, the three power-carrying circuits 51A to 51C can also be used as backup (redundancy) in case of failure. For example, when an open circuit (OPEN) failure occurs in the power-carrying circuit 51A during use, charging and discharging can be continued by using the other power-carrying circuits 51B and 51C.

[0117] (10) In the first embodiment, the output impedance Z is switched according to the purpose of the battery 20. In the second embodiment, the output impedance Z is switched according to the use status of the battery 20. The output impedance Z of the battery 20 is not limited to the purpose and use status of the battery 20, and the output impedance Z of the battery 20 may be switched according to the type of the vehicle 10. For example, the control device 100 of the battery 20 acquires information on the type of the vehicle 10 equipped with the battery 20 through communication with the vehicle ECU 16. When the vehicle 10 is a type of vehicle requiring a large maximum current, such as a large vehicle, the control device 100 switches the output impedance Z of the battery 20 to a small value. When the vehicle 10 is a type of vehicle requiring a small maximum current, such as a small vehicle, the output impedance Z of the battery 20 is switched to a large value. If this function is provided, the battery 20 can be used in common (shared) between vehicles of different types.

[0118] (11) In the first embodiment, the output impedance Z is switched according to the application of the battery 20. In the second embodiment, the output impedance Z is switched according to the use status of the battery 20. The output impedance Z of the battery 20 is not limited to the application and use status of the battery 20, and the output impedance Z of the battery 20 may be switched according to the internal resistance of the battery pack 30. For example, by changing the output impedance Z (from large to small) according to the change (from small to large) in the internal resistance of the battery pack 30, it is easy to keep the total resistance of the battery 20 constant regardless of the increase in internal resistance due to the lapse of time after manufacturing and long-term use. Therefore, it is possible to suppress heat generation while maintaining the power supply capacity to the load. The internal resistance of the battery pack 30 can be calculated based on the measured values ​​of the terminal voltage and current of the battery 20. Instead of the internal resistance, the output impedance of the battery 20 may be switched according to the deterioration state of the battery 20. That is, by reducing the output impedance Z of the battery 20 as the deterioration of the battery 20 progresses, it is possible to compensate for the reduction in output performance due to the deterioration. The deterioration state of the storage battery 20 can be determined by using, for example, the maintenance rate of the actual capacity (full charge capacity) based on the initial value at the time of manufacture as an indicator.

[0119] Explanation of symbols

[0120] 10. Cars

[0121] 20 Batteries

[0122] 31 units

[0123] 50 Switching Circuit

[0124] 51A~51C Power-on circuit

[0125] 100 Management device (control device).

Claims

1. A power storage device comprising: unit; a switching circuit located in a current path of the cell; and Control device, The switching circuit is a circuit for switching the output impedance of the power storage device. The control device switches the output impedance of the power storage device using the switching circuit according to a given condition.

2. The power storage device for a vehicle according to claim 1, wherein: The control device acquires information on the purpose of the power storage device or information on the use status of the power storage device through communication with the vehicle, and switches the output impedance of the power storage device according to the acquired information.

3. The power storage device for a vehicle according to claim 1, wherein: The control device acquires information on the type of the vehicle by communicating with the vehicle, and switches the output impedance of the power storage device according to the acquired information.

4. The power storage device according to claim 1, wherein The control device includes a storage unit storing information on the actual capacity of the power storage device or information on the purpose of use, and switches the output impedance of the power storage device according to the information on the actual capacity of the power storage device or the purpose of use stored in the storage unit.

5. The power storage device according to claim 1, wherein The control device switches the output impedance of the power storage device according to the internal resistance or degradation state of the cell.

6. The power storage device according to claim 1 or 2, wherein: The switching circuit is a plurality of energized circuits connected in parallel, Multiple energized circuits have different line resistances. The control device switches the output impedance of the power storage device by selecting or combining the energized circuits.

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