Method for controlling charging / discharging device

Abstract

To preferably increase a temperature of a power storage part while suppressing an increase in size of a device.SOLUTION: A charging and discharging device comprises: a temperature acquisition part that acquires a temperature of a power storage part or a housing part into which the power storage part is housed; a power conversion part that is provided onto a power transmission path between the power storage part and a power input part or a power transmission path between the power storage part and a power output part, and converts power by a power conversion operation; a temperature acquisition part that acquires a temperature of the power storage part or the housing part into which the power storage part is housed. A control method of the charging and discharging device, comprises the steps of: acquiring a temperature of the power storage part or the housing part by the temperature acquisition part; and performing the power conversion operation by the power conversion part when the temperature acquired by the temperature acquisition part is a predetermined value or less in a state where power is not input from the power input part and in a state where power is not output from the power output part.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a method for controlling a charge / discharge device that charges or discharges a power storage unit. [Background technology]

[0002] A known example of this type of device is one that charges a battery while managing the temperature of the battery stored in a storage compartment (see, for example, Patent Document 1). In the device described in Patent Document 1, a heater is provided below the storage compartment, and when the temperature of the battery falls below a predetermined temperature, the heater is driven to raise the temperature of the battery. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 11-98613 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the device described in Patent Document 1 requires space for installing the heater, which leads to an increase in the size of the device. [Means for solving the problem]

[0005] One aspect of the present invention is a control method for a charging / discharging device that constitutes at least one of a charging device that stores power input from a power input unit in a power storage unit and a discharging device that outputs power discharged from the power storage unit from a power output unit, wherein the charging / discharging device is provided on a power transmission path between the power storage unit and the power input unit or on a power transmission path between the power storage unit and the power output unit, and includes a power conversion unit that converts power through a power conversion operation, and a temperature acquisition unit that acquires the temperature of the power storage unit or the storage unit in which the power storage unit is housed, and the method includes the steps of: the temperature acquisition unit acquiring the temperature of the power storage unit or the storage unit; and the power conversion unit performing a power conversion operation when the temperature acquired by the temperature acquisition unit is below a predetermined value when no power is being input from the power input unit and no power is being output from the power output unit. [Effects of the Invention]

[0006] According to the present invention, it is possible to effectively increase the temperature of the power storage unit while suppressing an increase in the size of the device. [Brief explanation of the drawings]

[0007] [Figure 1A] 1 is a perspective view showing the external shape of a charging / discharging device according to a first embodiment of the present invention, with a battery removed; [Figure 1B] 1 is a perspective view showing the external shape of a charging / discharging device according to a first embodiment of the present invention, showing a state in which a battery is stored. [Figure 2] 1 is a front view showing the internal configuration of a charge / discharge device according to a first embodiment of the present invention. [Figure 3] 1 is a side view showing the internal configuration of a charge / discharge device according to a first embodiment of the present invention. [Figure 4] 1 is a diagram showing a schematic configuration of an electric circuit of a charge / discharge device according to a first embodiment of the present invention; [Figure 5] 1 is a block diagram showing the configuration of a control device that controls a charging / discharging device according to a first embodiment of the present invention. [Figure 6] 6 is a flowchart showing an example of processing executed by the controller of FIG. 5; [Figure 7A]FIG. 2 is a diagram showing an example of the operation of the charge / discharge device according to the first embodiment of the present invention. [Figure 7B] FIG. 3 is a diagram showing an example of the operation of a reference example of the charging / discharging device according to the first embodiment of the present invention. [Figure 8] FIG. 6 is a front view showing the internal configuration of a charge / discharge device according to a second embodiment of the present invention. [Figure 9] FIG. 6 is a side view showing the internal configuration of a charge / discharge device according to a second embodiment of the present invention. [Figure 10] FIG. 6 is a block diagram showing the configuration of a control device that controls a charging / discharging device according to a second embodiment of the present invention. [Figure 11] 11 is a flowchart showing an example of processing executed by the controller of FIG. 10; [Figure 12] FIG. 6 is a diagram showing an example of the operation of the charging / discharging device according to the second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0008] -First embodiment- A first embodiment of the present invention will be described below with reference to Figures 1A to 7B. A control method for a charge / discharge device according to the first embodiment of the present invention is applied to a charge / discharge device that constitutes a charger that charges a storage battery (secondary battery) such as a battery, and a discharger that discharges from the storage battery. Note that a case in which either a charger or a discharger is constituted is also included in the charge / discharge device. The charge / discharge device is, for example, a stationary power storage device installed on the premises of a house, and charges the battery with power from a commercial power source, while in the event of a power outage, it can supply power to loads within the house with power from the battery.

[0009] 1A and 1B are perspective views schematically illustrating the external shape of a charging / discharging device 100 according to a first embodiment of the present invention, showing the battery 200 removed and stored, respectively. For convenience, the following definitions will be used to define the front-to-rear direction (length direction), left-to-right direction (width direction), and up-to-down direction (height direction) as shown in the drawings, and the configuration of each part will be described according to these definitions. The up-to-down direction corresponds to the direction of gravity (vertical direction).

[0010] As shown in FIGS. 1A and 1B, the charging / discharging device 100 has a device main body 1 that houses a pair of batteries 200 of the same configuration. The device main body 1 has a housing 2 and a lid 3. The housing 2 has front, rear, left, and right side walls (front wall, rear wall, left wall, and right wall) that extend vertically, and a bottom wall that extends horizontally, and has a generally rectangular parallelepiped shape overall. A pair of left and right recessed storage compartments 4 with open tops are provided inside the housing 2. The storage compartments 4 are formed within the housing itself or by a member separate from the housing 2. The lid 3 is generally plate-shaped and is generally rectangular so as to cover the opening on the top surface of the housing 2. The lid 3 is rotatably supported by hinges 5 at the corners of the upper and rear ends of the housing 2.

[0011] Battery 200 is a portable battery weighing, for example, about 10 kg, and has a handle (not shown) on its top surface for a user to hold. Battery 200 may be lighter or heavier than 10 kg. Battery 200 is, for example, a lithium-ion battery, and has an overall, vertically elongated, approximately rectangular parallelepiped shape. Storage section 4 has a storage space 4a that is approximately rectangular parallelepiped in shape to match the external shape of battery 200.

[0012] The battery 200 is not limited to a rectangular parallelepiped shape, and various other shapes such as a cylindrical shape can be used. The number of batteries 200 in the housing 2 is not limited to two, and may be one, three, or more. Instead of or in addition to being arranged side by side in the left-right direction, the multiple batteries 200 may also be arranged side by side in the up-down or front-back direction. The storage section 4 is formed according to the shape, number, and arrangement of the batteries 200.

[0013] As shown in FIG. 1A, the battery 200 is accommodated in the accommodation space 4a from above with the lid 3 open. At this time, a battery-side terminal provided on the bottom surface (battery bottom surface) of the battery 200 is connected to an apparatus-side terminal provided on the bottom surface (accommodation section bottom surface) of the accommodation section 4 facing the accommodation space 4a. For example, the battery-side terminal is arranged in a recessed portion provided on the battery bottom surface, and the apparatus-side terminal is arranged in a protruding portion provided on the accommodation section bottom surface. As a result, when the battery-side terminal and the apparatus-side terminal are connected, the recessed portion and the protruding portion are fitted together, and the battery 200 is held in a positioned state in the accommodation section 4.

[0014] As shown in FIG. 1B , during normal use of the charging / discharging device 100, the lid 3 is closed with the entire battery housed in the housing space 4a. That is, the battery 200 is held in the housing 2 in a sealed state. The charging / discharging device 100 is provided with an input terminal for inputting AC power and an output terminal for outputting AC power. A male plug is provided at the input terminal, and the charging / discharging device 100 is connected to a commercial power source via the plug, so that AC power is input from the commercial power source to the charging / discharging device 100. A female outlet is provided at the output terminal, and a load is connected to the outlet, so that AC power is output from the charging / discharging device 100 to the load.

[0015] 2 and 3 are a front view (viewed from the front) and a side view (viewed from the left), respectively, that schematically show the internal configuration of the charge / discharge device 100 according to the first embodiment. As shown in FIGS. 2 and 3, the interior of the housing 2 is divided by a partition wall 7 that extends substantially horizontally into an upper chamber 8a and a lower chamber 8b below the upper chamber 8a. The upper chamber 8a includes a storage space 4a for the batteries 200, and a pair of left and right batteries 200 are disposed therein. A pair of left and right inverter units 10 are disposed below the left and right batteries 200 in the lower chamber 8b.

[0016] The inverter unit 10 is disposed on a power transmission path from the commercial power source to the battery 200 and on a power transmission circuit from the battery 200 to a load. The inverter unit 10 is a power conversion section including an AC / DC inverter and a DC / DC converter (see FIG. 4). AC power from the commercial power source is converted by the inverter unit 10 into DC power of a predetermined voltage and stored in the battery 200. DC power from the battery 200 is converted into AC power of a predetermined voltage by the inverter unit 10 and supplied to the load.

[0017] The lower chamber 8b is formed so that the left and right inverter units 10 are arranged in a single storage space. Alternatively, separate storage spaces for the left and right inverter units 10 may be provided, and the lower chamber 8b may be formed so that the storage spaces communicate with each other. Openings 2c (see FIG. 1B) penetrating the side walls 2a, 2b in the left-right direction are provided at the bottom of the left and right side walls 2a, 2b of the housing 2, respectively, and the lower chamber 8b communicates with the external space of the housing 2 via the openings 2c. Cooling fans 9a, 9b are provided in the side walls 2a, 2b, respectively, facing the openings 2c.

[0018] The left cooling fan 9a is an intake cooling fan, and as the cooling fan 9a rotates, air is drawn into the lower chamber 8b through the opening 9c. The right cooling fan 9b is an exhaust cooling fan, and as the cooling fan 9b rotates, air is expelled from the lower chamber 8b to the outside through the opening 9c. The rotation of the cooling fans 9a and 9b causes air to flow left and right within the lower chamber 8b, thereby cooling the inverter unit 10. At the same time, the cooling fans 9a and 9b can also cool the area around the inverter unit 10 (the housing 4 and the battery 200). In other words, the cooling fans 9a and 9b not only cool the inverter unit 10, but also function as cooling units that cool the battery 200 and the housing 4.

[0019] Although not shown in detail, a chamber (referred to as an electrical component chamber) in which electrical components such as a control unit, a junction box, and a pass-through are disposed is provided in addition to the upper chamber 8a and the lower chamber 8b within the housing 2. The electrical component chamber is provided, for example, to the left of the upper chamber 8a. The charging / discharging device 100 is connected to a commercial power source and a load via the electrical components in the electrical component chamber.

[0020] Fig. 4 is a diagram schematically showing the configuration of an electric circuit of charging / discharging device 100. As shown in Fig. 4, AC power is input to charging / discharging device 100 from a commercial power source via input terminal 11. On the other hand, DC power is output from charging / discharging device 100 to a load via output terminal 12. Input terminal 11 and output terminal 12 are respectively connected in parallel to a pair of inverter units 10 (Fig. 2) having the same configuration via switch circuit 13.

[0021] The pair of inverter units 10 may be referred to as a first inverter unit 10A and a second inverter unit 10B. Different batteries 200 are connected to the first inverter unit 10A and the second inverter unit 10B. The battery 200 connected to the first inverter unit 10A may be referred to as a first battery 200A, and the battery 200 connected to the second inverter unit 10B may be referred to as a second battery 200B.

[0022] Each inverter unit 10 has an inverter 14 and a converter 15. The inverter 14 is an AC / DC inverter and includes an inverter circuit having a switching element, a filter circuit, an NF circuit, etc. The inverter 14 converts direct current to alternating current by operation of the switching element, and generates an AC waveform. The converter 15 is a DC / DC converter and includes a bridge circuit having a switching element, a rectifier circuit, etc. The converter 15 steps up or down the DC voltage to a predetermined voltage by operation of the switching element.

[0023] The switch circuit 13 has a switch 131 that connects (ON) or disconnects (OFF) the input terminal 11 and the inverter unit 10 (first inverter unit 10A and second inverter unit 10B), a switch 132 that connects (ON) or disconnects (OFF) the output terminal 12 and the inverter unit 10 (first inverter unit 10A and second inverter unit 10B), and a switch 133 that connects (ON) or disconnects (OFF) the input terminal 11 and the output terminal 12 without passing through the switches 131 and 132. The switches 132 and 133 are C-contact switches that turn either one on or off the other.

[0024] When switch 131 is on and switches 132 and 133 are off, power from the commercial power source is supplied to battery 200 via input terminal 11 and inverter unit 10, and battery 200 is charged (charging operation). When switch 132 is on and switches 131 and 133 are off, power from battery 200 is supplied to the load via inverter unit 10 and output terminal 12, and battery 200 is discharged (discharging operation). When switch 133 is on and switches 131 and 132 are off, a pass-through state is established, and power from the commercial power source is supplied directly to the load via input terminal 11 and output terminal 12. That is, in this case, battery 200 is neither charged nor discharged and is in a standby state (standby operation).

[0025] The on / off of the switches 131 to 133 is controlled by a control unit in response to a signal from an SOC sensor or the like that detects the remaining capacity of the battery 200. When the battery 200 is being charged or discharged, the switching elements of the inverter unit 10 operate, and this operation is also controlled by the control unit.

[0026] Incidentally, in order to suppress performance degradation such as a decrease in the battery capacity and a decrease in the charge / discharge efficiency of battery 200, it is necessary to maintain the temperature of battery 200 within a predetermined temperature range. That is, a lower limit temperature and an upper limit temperature are predetermined for battery 200, and in order to ensure the desired performance of battery 200, it is necessary to maintain the battery temperature above the lower limit temperature and below the upper limit temperature.

[0027] In order to raise the battery temperature to or above the lower limit temperature, it is conceivable to provide a heater near the battery 200 and use the heat from the heater to raise the temperature of the battery 200. However, providing a heater near the battery 200 increases the size of the device main body 1, leading to increased costs. Therefore, in the first embodiment, the charging / discharging device 100 is controlled as follows to raise the temperature of the battery 200 without providing a heater.

[0028] FIG. 5 is a block diagram showing the configuration of a control device 101 that controls the charging / discharging device 100 according to the first embodiment. This control device 101 mainly controls the temperatures of the battery 200 and the inverter unit 10. As shown in FIG. 5, the control device 101 has a controller 20. The controller 20 is configured to include a computer having a CPU, ROM, RAM, an I / O interface, and other peripheral circuits. The controller 20 is included in the control unit of the charging / discharging device 100.

[0029] The inverter 14 and converter 15 of the first inverter unit 10A, the inverter 14 and converter 15 of the second inverter unit 10B, the first battery 200A, the second battery 200B, the intake fan motor 21, and the exhaust fan motor 22 are each communicatively connected to the controller 20. The intake fan motor 21 is an electric motor for driving the intake cooling fan 9a, and the exhaust fan motor 22 is an electric motor for driving the exhaust cooling fan 9b.

[0030] The inverter 14 and converter 15 of the first inverter unit 10A have temperature sensors 23 and 24 that detect the temperatures of the inverter 14 and converter 15, respectively. The inverter 14 and converter 15 of the second inverter unit 10B have temperature sensors 25 and 26 that detect the temperatures of the inverter 14 and converter 15, respectively. Signals from the temperature sensors 23 to 26 are input to the controller 20. Note that the temperature sensors 23 to 26 may be provided away from the inverter 14 and converter 15 as long as they are capable of detecting the temperatures of the inverter 14 and converter 15.

[0031] The first battery 200A and the second battery 200B are battery packs enclosed in respective housings, and each includes temperature sensors 27, 28 that detect the temperatures of the batteries 200A, 200B, and battery ECUs 29, 30 that receive signals from the temperature sensors 27, 28. The temperature sensors 27, 28 may be provided near the batteries 200A, 200B, rather than in the batteries themselves (battery packs themselves). That is, the temperature sensors 27, 28 may detect the temperature of a portion that has a correlation with the battery temperature. For example, the temperature sensors 27, 28 may be provided in the housings 4 of the batteries 200A, 200B, respectively, and the temperature of the housings 4 may be detected by the temperature sensors 27, 28.

[0032] Signals from sensors that detect various physical quantities such as current and voltage, as well as temperature sensors 27 and 28, are input to battery ECUs 29 and 30. Based on the signals from these sensors that detect the battery states, battery ECUs 29 and 30 calculate the charging rates SOC (State of Charge) and SOH (State of Health) of batteries 200A and 200B and transmit them as battery information to controller 20. The transmitted battery information includes temperature information of batteries 200A and 200B detected by temperature sensors 27 and 28.

[0033] Fig. 6 is a flowchart showing an example of the processing executed by the controller 20 of Fig. 5. The processing shown in this flowchart is repeated at predetermined intervals regardless of whether the battery 200 is being charged or discharged.

[0034] First, in step S1, the controller 20 reads signals from various sensors and switches, including the temperature sensors 23 to 28. Next, in step S2, the controller 20 determines whether the battery 200 is neither charging nor discharging, that is, whether the battery 200 is on standby. If the battery 200 is charging or discharging, the switches 131 and 132 in FIG. 4 are turned on. Therefore, the determination in step S2 is whether the switches 131 and 132 are off. If the determination in step S2 is affirmative, the process proceeds to step S3.

[0035] In step S3, the controller 20 determines whether the battery temperature Tb detected by the temperature sensors 27, 28 is equal to or lower than a predetermined value Tα. Specifically, it determines whether the lower of the temperature of the first battery 200A detected by the temperature sensor 27 (first battery temperature Tb1) and the temperature of the second battery 200B detected by the temperature sensor 28 (second battery temperature Tb2) is equal to or lower than the predetermined value Tα. The controller 20 may also determine whether the average value of the first battery temperature Tb1 and the second battery temperature Tb2 is equal to or lower than the predetermined value Tα. The predetermined value Tα is, for example, a lower limit temperature set to ensure battery performance. Note that the predetermined value Tα may be higher than the lower limit temperature.

[0036] If the result of step S3 is negative, the process proceeds to step S4. When the battery 200 is on standby, there is no need to perform power conversion in the charging / discharging device 100. Therefore, in step S4, the controller 20 stops the operation of both the first inverter unit 10A and the second inverter unit 10B. On the other hand, if the result of step S4 is positive, the process proceeds to step S5.

[0037] In step S5, the controller 20 outputs control signals to the first inverter unit 10A and the second inverter unit 10B to activate both the inverter units 10A and 10B. This causes the switching elements of the converter 15 to operate in a manner similar to the boost operation during discharge, and the switching elements of the inverter 14 to operate in a manner similar to the AC waveform generation operation. As a result, a predetermined voltage is applied to the output sections of the inverter units 10A and 10B. However, because the switch 132 is in the OFF state, the output sections are not connected to the load, and power from the battery 200 is not supplied to the load. Therefore, no current flows from the battery 200 to the load. However, when the switching elements of the inverter unit 10 are driven, the inverter unit 10 generates heat. This heat is transferred to the upper chamber 8a, thereby raising the temperature of the battery 200 in the upper chamber.

[0038] Once the inverter unit 10 is stopped in step S4 or operated in step S5, the process proceeds to step S6. In step S6, the controller 20 controls the intake and exhaust fan motors 21, 22 to stop the cooling fans 9a, 9b, and then ends the process. Note that stopping the cooling fans 9a, 9b in step S6 includes stopping the cooling fans 9a, 9b that are rotating and prohibiting the rotation of the cooling fans 9a, 9b that are stopped.

[0039] If it is determined in step S2 that the battery 200 is being charged or discharged, the result in step S2 is negative and the process proceeds to step S7. In step S7, the controller 20 outputs a control signal to the inverter unit 10 to charge or discharge the battery 200, thereby operating the inverter unit 10.

[0040] Next, in step S8, the controller 20 determines whether the battery temperature Tb detected by the temperature sensors 27, 28 is equal to or lower than the predetermined value Tα, as in step S3. If the result in step S8 is YES, the process proceeds to step S6, where the controller 20 stops the cooling fans 9a, 9b. In this case, the cooling fans 9a, 9b are stopped regardless of the temperature of the inverter unit 10 (inverter unit temperature Tin). On the other hand, if the result in step S8 is NO, the process proceeds to step S9.

[0041] In step S9, the controller 20 controls the fan motors 21 and 22 to operate or stop the cooling fans 9a and 9b based on the inverter unit temperature Tin detected by the temperature sensors 23 to 26. Specifically, the controller 20 first calculates the inverter unit temperature Tin as a representative value of the temperatures of the inverter 14 and the converter 15 based on the values ​​detected by the temperature sensors 23 to 26. If the inverter unit temperature Tin is equal to or greater than a predetermined value, the controller 20 starts the cooling fans 9a and 9b. If the inverter unit temperature Tin is less than the predetermined value, the controller 20 stops the cooling fans 9a and 9b. The inverter unit temperature Tin is, for example, the largest value among the values ​​detected by the temperature sensors 23 to 26. Note that the average value of the values ​​detected by the temperature sensors 23 to 26 may be used as the inverter unit temperature Tin. The rotation speed of the cooling fans 9a and 9b may be configured to be variable, and the controller 20 may change the rotation speed of the cooling fans 9a and 9b according to the inverter unit temperature Tin. In other words, the rotation speed of the cooling fans 9a and 9b may be increased as the inverter unit temperature Tin increases.

[0042] Fig. 7A is a diagram illustrating an operation of the control method for the charge / discharge device according to the first embodiment, and Fig. 7B is a diagram illustrating the operation as a reference example of Fig. 7A. In the reference example, the charge / discharge device has a built-in heater for heating the battery 200.

[0043] 7A, in the first embodiment, when the battery 200 is being charged or discharged (charging or discharging), the inverter unit 10 operates regardless of the battery temperature Tb to perform the charging or discharging operation (step S7). Furthermore, when the battery temperature Tb is in a low temperature state below a predetermined value Tα, the cooling fans 9a and 9b stop regardless of the inverter unit temperature Tin (step S6), and when the battery temperature Tb is in a normal temperature or high temperature state above the predetermined value Tα, the cooling fans 9a and 9b operate or stop according to the inverter unit temperature Tin (step S9).

[0044] On the other hand, when the battery 200 is not being charged or discharged and is on standby, if the battery temperature Tb is higher than the predetermined value Tα, the inverter unit 10 stops operating (step S4). In contrast, if the battery temperature Tb becomes equal to or lower than the predetermined value Tα, the inverter unit 10 operates (switching operation) (step S5). This causes the inverter unit 10 to generate heat, and the temperature of the battery 200 arranged above the inverter unit 10 rises. As a result, it is possible to prevent the battery temperature Tb from becoming equal to or lower than the predetermined value Tα without providing a heater.

[0045] As shown in FIG. 7B, if a heater is provided in the charging / discharging device, the heater operates when the battery temperature Tb falls below a predetermined value Tα while the device is waiting to charge or discharge. This heats up the battery 200, causing it to rise in temperature. At this time, the inverter unit 10 stops operating. Also, while the battery 200 is being charged or discharged, the heater operates when the battery temperature Tb falls below the predetermined value Tα. At this time, the cooling fans 9a and 9b operate or stop operating based on the inverter unit temperature Tin.

[0046] According to the first embodiment described above, the following advantageous effects can be achieved. (1) The control method for a charging / discharging device is a method for controlling charging / discharging device 100, which constitutes a charging device that stores power input from input terminal 11 in battery 200 and a discharging device that outputs power discharged from battery 200 from output terminal 12. Charging / discharging device 100 is provided on a power transmission path between battery 200 and input terminal 11 and on a power transmission path between battery 200 and output terminal 12, and includes inverter unit 10 that converts power through a power conversion operation, and temperature sensors 27, 28 that detect the temperature of battery 200 (FIGS. 4 and 5). The control method includes a step S1 of acquiring temperature information of battery 200 detected by temperature sensors 27, 28, and a step S5 of operating inverter unit 10 when battery temperature Tb detected by temperature sensors 27, 28 is equal to or lower than predetermined value Tα in a state where power is not being input from input terminal 11 and power is not being output from output terminal 12, i.e., in a standby state where charging / discharging is not being performed (FIG. 6).

[0047] With this configuration, while waiting for charging or discharging, the inverter unit 10 operates to raise the temperature of the battery 200, preventing performance degradation of the battery 200 due to a drop in the battery temperature Tb. Furthermore, since the battery 200 is heated without using a heater, an increase in the number of parts is not required, which suppresses cost increases and prevents the charging / discharging device 100 from becoming larger.

[0048] (2) The inverter unit 10 is disposed vertically below the battery 200 (FIG. 2). When the inverter unit 10 generates heat, the air around the inverter unit 10 is heated and rises. Therefore, by disposing the inverter unit 10 below the battery 200, the heat generated by the inverter unit 10 can efficiently raise the temperature of the battery 200.

[0049] (3) Battery 200 includes first battery 200A and second battery 200B arranged in parallel with each other (FIG. 4). Inverter unit 10 includes first inverter unit 10A provided on the power transmission path between first battery 200A and input terminal 11 and on the power transmission path between first battery 200A and output terminal 12, and second inverter unit 10B provided on the power transmission path between second battery 200B and input terminal 11 and on the power transmission path between second battery 200B and output terminal 12 (FIG. 4). In a standby state in which no charging or discharging is performed, power conversion operation (switching operation) is performed by operating first inverter unit 10A and second inverter unit 10B when the lower of a first battery temperature Tb1 detected by temperature sensor 27 and a second battery temperature Tb2 detected by temperature sensor 28 is equal to or lower than a predetermined value Tα (step S3). As a result, when a plurality of batteries 200 are housed in the charging / discharging device 100, the temperatures of all the batteries 200 can be maintained at or above the lower limit temperature.

[0050] (4) The charging / discharging device 100 further includes cooling fans 9a and 9b that cool the inverter unit 10, the housing 4, and the battery 200 (FIG. 2). The control method further includes a step (step S8 → step S6) of stopping (stopping or prohibiting) the operation of the cooling fans 9a and 9b when the battery temperature Tb detected by the temperature sensors 27 and 28 is equal to or lower than a predetermined value Tα during charging / discharging (FIG. 6). This prevents the cooling fans 9a and 9b from operating unnecessarily, thereby reducing the power consumption of the charging / discharging device 100.

[0051] -Second embodiment- A second embodiment of the present invention will be described with reference to Figures 8 to 12. Differences from the first embodiment will be mainly described below. The second embodiment differs from the first embodiment in that the charging / discharging device 100 has a heater in case the battery temperature Tb is extremely low. However, since the heater is used as an auxiliary device, the amount of heat required for the heater is not very large.

[0052] 8 and 9 are a front view and a side view, respectively, schematically illustrating the internal configuration of the charging / discharging device 100 according to the second embodiment. The same components as those in FIGS. 2 and 3 are designated by the same reference numerals. As shown in FIGS. 8 and 9, a pair of heaters (heating wires) 30 are provided on the front wall 2d of the housing 2, facing the pair of batteries 200, so as to heat each battery 200. However, because the heaters 31 do not need to generate a large amount of heat, they are smaller than those in the reference example (FIG. 7B). Therefore, cost increases are kept to a minimum, and the heaters 31 can be easily arranged.

[0053] The heater facing the first battery 200A may be referred to as the first heater 31A, and the heater facing the second battery 200B may be referred to as the second heater 31B. The heater 31 may be provided to heat the housing portion 4 instead of the battery 200. That is, heat from the heater 31 may be transferred to the battery 200 via the housing portion 4 to raise the temperature of the battery 200.

[0054] FIG. 10 is a block diagram showing the configuration of a control device 101 that controls a charging / discharging device 100 according to the second embodiment. The same components as those in FIG. 5 are denoted by the same reference numerals. As shown in FIG. 10, in addition to the components shown in FIG. 5, a pair of heaters 31A and 31B are connected to the controller 20. The pair of heaters 31A and 31B are controlled by the controller 20.

[0055] Fig. 11 is a flowchart showing an example of processing executed by the controller 20 of Fig. 10. Note that the same reference numerals are used for the same parts as in Fig. 6. As shown in Fig. 11, in the second embodiment, after controlling the cooling fans 9a and 9b in step S6 or step S9, the process proceeds to step S10.

[0056] In step S10, the controller 20 determines whether the battery temperature Tb detected by the temperature sensors 27, 28, more specifically, the lower of the first battery temperature Tb1 and the second battery temperature Tb2, is equal to or lower than a predetermined value Tβ. The predetermined value Tβ is set to a value lower than the predetermined value Tα. For example, it is set to a lower limit temperature for preventing performance degradation of the battery 200. This determination is made to determine whether the battery 200 is not simply at a low temperature, but is in an extremely low temperature state. If the result of step S10 is negative, the process proceeds to step S11, and if the result of step S10 is positive, the process proceeds to step S12.

[0057] In step S11, the controller 20 stops the pair of heaters 31A, 31B. Note that stopping the heaters means stopping the operation of the heaters 31A, 31B if they are operating, or prohibiting the operation of the heaters 31A, 31B if they are stopped. In step S12, the controller 20 outputs control signals to the heaters 31A, 31B to operate the heaters 31A, 31B.

[0058] Fig. 12 is a diagram summarizing the operations of the control method for the charge / discharge device according to the second embodiment. Fig. 12 is a diagram in which the operation of the heater 31 is added to Fig. 7A, and the operations of the inverter unit 10 and the cooling fans 9a and 9b are the same as those shown in Fig. 7A.

[0059] 12, when the battery temperature Tb is at an extremely low temperature equal to or lower than a predetermined value Tβ, the heater 31 operates (step S12) whether the battery 200 is being charged or discharged or is in standby mode. This heats the battery 200, allowing the battery temperature Tb to be quickly raised to equal to or higher than the predetermined value Tβ. That is, even when the charging / discharging device 100 is used in a cold climate or the like and the amount of heat generated by the inverter unit 10 alone is insufficient to raise the temperature of the battery 200, the battery 200 can be reliably raised to equal to or higher than the lower limit temperature.

[0060] According to the second embodiment, in addition to the effects of the first embodiment, the following effects can be achieved. That is, the charging / discharging device 100 further includes a heater 31 that heats the battery 200 (FIG. 8). The control method further includes a step (step S12) of activating the heater 31 when the battery temperature Tb detected by the temperature sensors 27, 28 is equal to or lower than a predetermined value Tβ that is lower than the predetermined value Tα (FIG. 11). This makes it possible to maintain the battery temperature Tb at or above the lower limit temperature even when the battery 200 is used in cold climates, and thus suppress performance degradation of the battery 200. The heater 31 is used as an auxiliary heater when the amount of heat generated by the inverter unit 10 alone is insufficient. This allows the use of a small heater 31 that generates a small amount of heat, thereby preventing the charging / discharging device 100 from becoming larger.

[0061] Other embodiments or modifications will be described below. In the above embodiment, the left and right inverter units 10A, 10B (FIG. 2) are controlled in the same manner, but they may be controlled in different manners. For example, during standby for charging or discharging, the first inverter unit 10A may be controlled in accordance with the temperature Tb1 of the first battery 200A, and the second inverter unit 10B may be controlled in accordance with the temperature Tb2 of the second battery 200B. That is, the left and right inverter units 10A, 10B may be controlled independently of each other. Similarly, the left and right heaters 31A, 31B (FIG. 8) may be controlled independently of each other in accordance with the first battery temperature Tb1 and the second battery temperature Tb2.

[0062] In the above embodiment, AC power input from input terminal 11 as a power input unit is charged into battery 200, and AC power discharged from battery 200 is output from output terminal 12 as a power output unit, but the form of power input from the power input unit and power output from the power output unit is not limited to what has been described above and may be DC power. In the above embodiment, battery 200 is accommodated in accommodation unit 4 of charging / discharging device 100, but a capacitor may also be accommodated in the accommodation unit, and the configuration of the power storage unit is not limited to what has been described above.

[0063] In the above embodiment (FIG. 4), inverter unit 10 having inverter 14 and converter 15 that convert power by a power conversion operation is arranged on the power transmission path between battery 200 and input terminal 11 and on the power transmission path between battery 200 and output terminal 12, but the configuration and arrangement of the power conversion unit are not limited to those described above. The power conversion unit may be arranged on the power transmission path between battery 200 and input terminal 11 or on the power transmission path between battery 200 and output terminal 12. In the above embodiment, temperature sensors 27, 28 are used to detect the temperature of battery 200 or storage unit 4, but the configuration of the temperature acquisition unit that acquires the temperature of the power storage unit or storage unit is not limited to those described above.

[0064] In the above embodiment, inverter unit 10 is disposed vertically below battery 200, but the positional relationship of the power conversion unit with respect to the power storage unit is not limited to that described above as long as the temperature of the power storage unit can be increased by heat from the power conversion unit. In the above embodiment, when the lower temperature Tb of the temperature of first battery 200A (first power storage unit) detected by temperature sensor 27 or the temperature of second battery 200B (second power storage unit) detected by temperature sensor 28 is equal to or lower than predetermined value Tα, first inverter unit 10A (first power conversion unit) and second inverter unit 10B (second power conversion unit) perform power conversion operation, but the power conversion operation may be performed in other ways.

[0065] In the above embodiment, the charging / discharging device 100 is configured to have cooling fans 9a, 9b that cool the inverter unit 10 and the battery 200, but the configuration of the cooling unit is not limited to that described above. A cooling unit may be provided to cool the storage unit that stores the power storage unit. In the above second embodiment, the charging / discharging device 100 is provided with the heater 31, which is an electric heating wire that heats the battery 200 or the storage unit 4, and the heater 31 is activated when the battery temperature Tb is equal to or lower than a predetermined value Tβ (second predetermined value) that is lower than a predetermined value Tα (first predetermined value), but the configuration of the heating unit is not limited to that described above.

[0066] The above embodiment has described an example in which the control method is applied to a charging device capable of charging battery 200 and charging / discharging device 100 having functions as a discharging device capable of discharging battery 200, but the present invention can be similarly applied to a charging / discharging device having only the function of a charging device that stores power input from a power input unit in a power storage unit, and a charging / discharging device having only the function of a discharging device that outputs power output from a power storage unit from a power output unit. Therefore, the step of performing a power conversion operation included in the control method may be a step in which the power conversion unit performs a power conversion operation when power is not being input from the power input unit and power is not being output from the power output unit and the temperature acquired by the temperature acquisition unit is equal to or lower than a predetermined value.

[0067] In the above embodiment, an example in which the charging / discharging device 100 is installed on the premises of a house has been described, but the charging / discharging device to which the present invention is applied can be installed in various places, not limited to on the premises of a house. In the above embodiment, the charging / discharging device 100 is a stationary type, but the charging / discharging device may also be installed in a movable type.

[0068] The above description is merely an example, and the present invention is not limited to the above-described embodiment and modifications as long as the features of the present invention are not impaired. One or more of the above-described embodiment and modifications can be arbitrarily combined, and modifications can also be combined with each other. [Explanation of symbols]

[0069] 4 Housing, 9a, 9b Cooling fan, 10 Inverter unit, 10A First inverter unit, 10B Second inverter unit, 11 Input terminal, 12 Output terminal, 27, 28 Temperature sensor, 31 Heater, 100 Charging / discharging device, 200 Battery, 200A First battery, 200B Second battery

Claims

1. A control method for a charging / discharging device constituting at least one of a charging device that stores power input from a power input unit in a power storage unit and a discharging device that outputs power discharged from the power storage unit from a power output unit, comprising: the charging / discharging device includes: a power conversion unit that is provided on a power transmission path between the power storage unit and the power input unit or on a power transmission path between the power storage unit and the power output unit and that converts power through a power conversion operation; and a temperature acquisition unit that acquires a temperature of the power storage unit or a storage unit that accommodates the power storage unit; a step in which the temperature acquisition unit acquires a temperature of the power storage unit or the accommodation unit; a step of the power conversion unit performing the power conversion operation when the temperature acquired by the temperature acquisition unit is equal to or lower than a predetermined value in a state in which no power is being input from the power input unit and no power is being output from the power output unit.

2. The method for controlling a charging / discharging device according to claim 1, The method for controlling a charging / discharging device, wherein the power conversion unit is disposed vertically below the power storage unit.

3. 3. The method for controlling a charging / discharging device according to claim 1, the power storage unit includes a first power storage unit and a second power storage unit arranged in parallel with each other, the power conversion unit includes a first power conversion unit provided on a power transmission path between the first power storage unit and the power input unit or on a power transmission path between the first power storage unit and the power output unit, and a second power conversion unit provided on a power transmission path between the second power storage unit and the power input unit or on a power transmission path between the second power storage unit and the power output unit, A method for controlling a charging / discharging device, characterized in that the step of performing the power conversion operation includes a step of the first power conversion unit and the second power conversion unit performing the power conversion operation when, in a state where no power is being input from the power input unit and no power is being output from the power output unit, the lower of the temperature of the first storage unit or the temperature of the second storage unit acquired by the temperature acquisition unit is below the predetermined value.

4. The method for controlling a charging / discharging device according to any one of claims 1 to 3, the charging / discharging device further includes a cooling unit that cools the power conversion unit, the power storage unit, or the storage unit; A control method for a charging / discharging device, characterized in that it further includes a step of stopping or prohibiting operation of the cooling unit when the temperature acquired by the temperature acquisition unit is below a predetermined value while power is being input from the power input unit or while power is being output from the power output unit.

5. The method for controlling a charging / discharging device according to any one of claims 1 to 3, the charging / discharging device further includes a heating unit that heats the power storage unit or the storage unit, the predetermined value is a first predetermined value, The method for controlling a charging / discharging device further comprises the step of activating the heating unit when the temperature acquired by the temperature acquisition unit is equal to or lower than a second predetermined value that is lower than the first predetermined value.

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