power supply

Abstract

To provide a power supply device capable of performing appropriate charging / discharging regardless of configuration of each battery.SOLUTION: Assuming that n is an integer greater than or equal to 2, a power supply device 10 has first to n-th batteries, first to n-th power conversion circuits for converting charging / discharging power to the first to n-th batteries, and a control part 15 capable of controlling the first to n-th power conversion circuits. The control part 15 is capable of performing residual capacity ratio control for the first to n-th power conversion circuits so that first to n-th residual capacity ratios approach first to n-th discharge power ratios. The control part 15 is also capable of performing empty capacity ratio control for controlling the first to n-th power conversion circuits so that first to n-th empty capacity ratios approach first to n-th charge power ratios.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a power supply device. [Background technology]

[0002] The power conditioner described in Patent Document 1 includes two storage batteries, two DC-DC converters for each storage battery, a DC-DC converter control unit, and a command unit. Each DC-DC converter controls the discharge power or charge power of each storage battery. The DC-DC converter control unit controls each DC-DC converter individually based on a command value output from the command unit. The command unit outputs a command value for discharge power or a command value for charge power for each storage battery so that the SOC (State Of Charge) of each storage battery is equal. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2020 / 255624 Summary of the Invention [Problem to be solved by the invention]

[0004] A power conditioner with different configurations, such as the amount of power that the two storage batteries can store and the maximum discharge power that the two storage batteries can output, has a problem in that when the SOC of each storage battery is controlled to be equal, the charging power supplied to the two storage batteries cannot be effectively utilized. Note that the charging power referred to here includes not only charging power supplied from an external power source but also power that has been charged and stored in the storage batteries, i.e., power that the storage batteries can discharge. Therefore, an object of the present invention is to provide a power conditioner that can appropriately charge and discharge batteries even if the configurations, such as the amount of power that the batteries can store and the maximum discharge power, differ. [Means for solving the problem]

[0005] In order to solve the above problem, one aspect of the present invention is a power supply device comprising: first to n-th batteries; first to n-th power conversion circuits corresponding to the first to n-th batteries, respectively, and converting charge and discharge power, where n is an integer of 2 or greater; and a control unit capable of controlling the first to n-th power conversion circuits; wherein, when the amounts of power that can be stored in the first to n-th batteries are defined as first to n-th capacities, respectively, the rated power that can be discharged by the first to n-th batteries are defined as first to n-th discharge powers, respectively, and the amounts of power stored in the first to n-th batteries are defined as first to n-th remaining capacities, respectively, x is an integer between 1 and n, and y is an integer between 1 and n, both inclusive, and different from x, at least one of the ratio between the x-th capacity and the y-th capacity and the ratio between the x-th discharge power and the y-th discharge power is not 1:1, and the control unit is capable of performing remaining capacity ratio control to control the first to n-th power conversion circuits so that the ratio of the first to n-th remaining capacities approaches the ratio of the first to n-th discharge powers.

[0006] With this configuration, even if there are differences in the maximum amount of power that each battery can store, the maximum discharge power that each battery can discharge, or the maximum charge power that each battery can charge, it is unlikely that the remaining capacity of one battery will reach zero first. Therefore, even if the configurations of the amount of power that can be stored and the discharge power differ from battery to battery, appropriate discharge can be performed.

[0007] Furthermore, in order to solve the above problem, one aspect of the present invention provides a battery charger including: first to n-th batteries, where n is an integer of 2 or more; first to n-th power conversion circuits corresponding to the first to n-th batteries, respectively, for converting charge and discharge power; and a control unit capable of controlling the first to n-th power conversion circuits, wherein rated powers that can be charged into the first to n-th batteries are defined as first to n-th charging powers, and amounts of power that can be stored in the first to n-th batteries are defined as first to n-th capacities, respectively, and the first to n-th capacities and the corresponding first to n-th The power supply device is capable of performing free capacity ratio control to control the first to nth power conversion circuits so that the ratio of the first to nth free capacities approaches the ratio of the first to nth charging powers, where x is an arbitrary integer between 1 and n, and y is an arbitrary integer between 1 and n, different from x, and at least one of the ratios of the xth capacity to the yth capacity and the ratio of the xth charging power to the yth charging power is not 1:1, when the difference between the first to nth free capacities and the amount of power stored in the nth battery is respectively defined as 1st to nth free capacities, x is an arbitrary integer between 1 and n, and y is an arbitrary integer between 1 and n, different from x.

[0008] With this configuration, even if there are differences in the maximum amount of power that each battery can store, the maximum discharge power that each battery can discharge, or the maximum charge power that each battery can charge, it is unlikely that the free capacity of one battery will reach zero first. Therefore, even if the configurations of the amount of power that can be stored and the discharge power that each battery can discharge are different, appropriate charging can be performed. [Effects of the Invention]

[0009] The objective is to provide a power conditioner that can effectively utilize the charging power supplied to two storage batteries, regardless of the configuration of each battery. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic diagram of the overall configuration of a power supply device. [Figure 2] FIG. 10 is an explanatory diagram of remaining capacity ratio control. [Figure 3] FIG. 4 is an explanatory diagram of remaining capacity ratio control. [Figure 4] FIG. 4 is an explanatory diagram of remaining capacity ratio control. DETAILED DESCRIPTION OF THE INVENTION

[0011] <One embodiment of the power supply device> An embodiment of a power supply device will be described below with reference to the drawings. (Overall structure) 1, the power supply device 10 includes a PV converter 11 and an inverter 12. The power supply device 10 further includes a first power conversion circuit 13A, a first battery 14A, a second power conversion circuit 13B, a second battery 14B, and a control unit 15.

[0012] The PV converter 11 is connected to a solar panel 20. The solar panel 20 is a DC power supply that generates power using sunlight. The PV converter 11 converts the DC voltage input from the solar panel 20 into a DC voltage of a predetermined voltage value.

[0013] The inverter 12 is connected to the solar panel 20 via the PV converter 11. The inverter 12 is connected to the first battery 14A via the first power conversion circuit 13A. The inverter 12 is connected to the second battery 14B via the second power conversion circuit 13B. The inverter 12 converts DC power input from the first battery 14A, the second battery 14B, or the solar panel 20 into AC power and outputs the AC power.

[0014] The inverter 12 is connected to an external power source 22 and a load 23 via a power line 21. The external power source 22 is, for example, a commercial power distribution system through which a power company transmits power. The external power source 22 includes electrical equipment (not shown), such as a distribution board, a watt-hour meter, and a power outlet. The load 23 is an electrical device that operates using AC power from the power line 21. Therefore, the load 23 can be supplied with power from the first battery 14A, the second battery 14B, and the solar panel 20. The load 23 can also be supplied with power from an external power source 22 other than the first battery 14A and the second battery 14B. The load 23 is, for example, a lighting fixture, a server, a medical device, or a household electrical appliance.

[0015] The first battery 14A is connected to the solar panel 20 via the first power conversion circuit 13A and the PV converter 11. Therefore, the first battery 14A can store the power generated by the solar panel 20. The first battery 14A can also output power to the load 23. The first battery 14A is, for example, a lithium-ion battery.

[0016] The first power conversion circuit 13A is a DC-DC converter. The first power conversion circuit 13A converts the charging and discharging power for the first battery 14A. More specifically, the first power conversion circuit 13A converts the voltage value of the power generated by the solar panel 20 to a predetermined voltage value and charges the first battery 14A. The first power conversion circuit 13A also converts the voltage value of the power stored in the first battery 14A to a predetermined voltage value and discharges it to the inverter 12.

[0017] The amount of power that the first battery 14A can store is referred to as the first capacity. In this embodiment, the first capacity refers to a design value of the maximum amount of power that the first battery 14A can store. The amount of power stored in the first battery 14A is referred to as the first remaining capacity. The units of the first capacity and the first remaining capacity are, for example, Wh (watt-hours). The rated power that the first battery 14A can discharge via the first power conversion circuit 13A is referred to as the first discharging power. The maximum power that can be charged to the first battery 14A via the first power conversion circuit 13A is referred to as the first charging power. The first discharging power is the maximum power output from the first power conversion circuit 13A when the first battery 14A is solely discharged. The first charging power is the maximum power input to the first power conversion circuit 13A when the first battery 14A is solely charged. The first discharging power and the first charging power are values ​​that change depending on operating conditions such as temperature, the rated value of the first power conversion circuit 13A, and the like. The unit of the first discharge power and the first charge power is, for example, W (watts).

[0018] The second battery 14B is connected to the solar panel 20 via the second power conversion circuit 13B and the PV converter 11. Therefore, the second battery 14B can store the power generated by the solar panel 20. The second battery 14B can also output power to the load 23. The second battery 14B is, for example, a lithium-ion battery.

[0019] The second power conversion circuit 13B is a DC-DC converter. The second power conversion circuit 13B converts the charging and discharging power for the second battery 14B. More specifically, the second power conversion circuit 13B converts the voltage value of the power generated by the solar panel 20 to a predetermined voltage value and charges the second battery 14B. The second power conversion circuit 13B also converts the voltage value of the power stored in the second battery 14B to a predetermined voltage value and discharges it to the inverter 12.

[0020] The amount of power that can be stored in the second battery 14B is referred to as the second capacity. In this embodiment, the second capacity refers to a design value of the maximum amount of power that the second battery 14B can store. The amount of power stored in the second battery 14B is referred to as the second remaining capacity. The units of the second capacity and the second remaining capacity are, for example, Wh (watt-hours). The rated power of the second battery 14B via the second power conversion circuit 13B is referred to as the second discharging power. The maximum power that can be charged to the second battery 14B via the second power conversion circuit 13B is referred to as the second charging power. The second discharging power is the maximum power output from the second power conversion circuit 13B when the second battery 14B is solely discharged. The second discharging power is the maximum power input to the second power conversion circuit 13B when the second battery 14B is solely charged. The second discharging power and the second charging power are values ​​that change depending on operating conditions such as temperature, the rated value of the second power conversion circuit 13B, and the like. The second discharge power and the second charge power are expressed in units of, for example, W (watts).

[0021] The first battery 14A and the second battery 14B have different configurations. Specifically, the first capacity of the first battery 14A is different from the second capacity of the second battery 14B. Furthermore, the first discharge power of the first battery 14A is different from the second discharge power of the second battery 14B. Furthermore, the first charge power of the first battery 14A is different from the second charge power of the second battery 14B. As a result, the ratio between the first capacity and the second capacity, the ratio between the first discharge power and the second discharge power, and the ratio between the first charge power and the second charge power are not all 1:1.

[0022] The control unit 15 is capable of acquiring information related to the power supply device 10. The control unit 15 can acquire the first SOC (State of Charge) of the first battery 14A and the second SOC of the second battery 14B using a known method. For example, the control unit 15 calculates the first SOC by dividing the integrated value of the amount of power charged and discharged by the first power conversion circuit 13A by the first capacity. Similarly, the control unit 15 calculates the second SOC by dividing the integrated value of the amount of power charged and discharged by the second power conversion circuit 13B by the second capacity. The first SOC is the ratio of the first remaining capacity of the first battery 14A to the first capacity. The second SOC is the ratio of the second remaining capacity of the second battery 14B to the second capacity. The first SOC and the second SOC are expressed as percentages.

[0023] The control unit 15 can acquire a first SOH (State of Health) and a second SOH using a known method. The first SOH is a ratio of a first capacity of the current first battery 14A to a first capacity of the first battery 14A immediately after manufacture. The second SOH is a ratio of a second capacity of the current second battery 14B to a second capacity of the second battery 14B immediately after manufacture. The first SOH and the second SOH are expressed as percentages. The control unit 15 can correct the first capacity or the first SOC to an appropriate value based on the first SOH. The control unit 15 can also correct the second capacity or the second SOC to an appropriate value based on the second SOH.

[0024] The control unit 15 can acquire a first remaining capacity and a second remaining capacity. The control unit 15 calculates the first remaining capacity by, for example, multiplying the first capacity by the first SOC. The control unit 15 calculates the second remaining capacity by, for example, multiplying the second capacity by the second SOC. The first remaining capacity and the second remaining capacity are expressed in units of, for example, Wh (watt-hours).

[0025] The control unit 15 can acquire a first free capacity and a second free capacity. The control unit 15 calculates the first free capacity as the difference between the first capacity and the first remaining capacity. The control unit 15 calculates the second free capacity as the difference between the second capacity and the second remaining capacity. The first free capacity and the second free capacity are expressed in units of, for example, Wh (watt-hours).

[0026] The control unit 15 can acquire whether or not the power supply from the external power source 22 to the load 23 has been interrupted, that is, whether or not the external power source 22 has experienced a power outage. For example, a voltage sensor or the like (not shown) is provided on the power line 21. The control unit 15 determines whether or not the external power source 22 has experienced a power outage based on the detection result of the voltage sensor or the like.

[0027] The control unit 15 can control switching between grid-connected operation of the power supply device 10 and the external power source 22 and stand-alone operation of the power supply device 10 through control of the inverter 12 and a relay circuit (not shown), etc. For example, when the power demand of the load 23 exceeds the power supply of the power supply device 10, the control unit 15 can switch the power supply device 10 to grid-connected operation, thereby making it possible to make up for the power shortage with the external power source 22. Furthermore, when the power supply from the external power source 22 is cut off, the control unit 15 can switch the power supply device 10 to stand-alone operation, thereby making it possible for the power supply device 10 to supply power to the load 23 on its own.

[0028] The control unit 15 can individually control the first power conversion circuit 13A and the second power conversion circuit 13B. That is, the control unit 15 can control the charge / discharge power of the first battery 14A through control of the first power conversion circuit 13A. The control unit 15 can also control the charge / discharge power of the second battery 14B through control of the second power conversion circuit 13B. The control unit 15 basically controls the charge / discharge power of each battery so that the first SOC and the second SOC have the same value. When predetermined conditions are met, the control unit 15 can execute remaining capacity ratio control and empty capacity ratio control, which will be described later.

[0029] (Regarding remaining capacity ratio control) The remaining capacity ratio control performed by the control unit 15 will be described below. The remaining capacity ratio control is the following control. The remaining capacity ratio control is applied to a power supply device including first to n-th batteries, first to n-th power conversion circuits corresponding to the first to n-th batteries, respectively, and converting charge / discharge power, and a control unit capable of controlling the first to n-th power conversion circuits (where n is an integer of 2 or more). In this power supply device, the rated powers that the first to n-th batteries can discharge are defined as first to n-th discharge powers, respectively. The amounts of power stored in the first to n-th batteries are defined as first to n-th remaining capacities, respectively. The remaining capacity ratio control is control performed by the control unit on the first to n-th power conversion circuits so that the ratios of the first to n-th remaining capacities approach the ratios of the first to n-th discharge powers. More specifically, the remaining capacity ratio control performs the following control. Let x be any integer between 1 and n, inclusive, and y be any integer between 1 and n, inclusive, different from x. In remaining capacity ratio control, when the value obtained by dividing the xth remaining capacity by the xth discharge power is smaller than the value obtained by dividing the yth remaining capacity by the yth discharge power, the control unit 15 controls the xth power conversion circuit and the yth power conversion circuit so that the power discharged from the xth battery is smaller than the power discharged from the yth battery.

[0030] In this embodiment, n is 2. In this embodiment, the ratio of the first capacity to the second capacity is 2:3. The ratio of the first discharge power to the second discharge power is 1:2. In other words, neither the ratio of the first capacity to the second capacity nor the ratio of the first discharge power to the second discharge power is 1:1. The remaining capacity ratio control in this embodiment refers to control performed by the control unit 15 on the first power conversion circuit 13A and the second power conversion circuit 13B so that the ratio between the first remaining capacity of the first battery 14A and the second remaining capacity of the second battery 14B approaches the ratio between the first discharge power of the first battery 14A and the second discharge power of the second battery 14B. The remaining capacity ratio control will be specifically described below.

[0031] The control unit 15 determines whether or not the execution condition for remaining capacity ratio control is satisfied at each predetermined control period while power is being supplied from the first battery 14A and the second battery 14B to the load 23. The execution condition for remaining capacity ratio control is that one or more of the following requirements (a) to (d) are satisfied:

[0032] (a) The power demand of the load 23 is greater than a predetermined specified power. The specified power is set to, for example, a value slightly smaller than the sum of the first discharge power of the first battery 14A and the second discharge power of the second battery 14B. That is, the requirement (a) is for determining a situation in which both the first battery 14A and the second battery 14B must be discharged to approximately their maximum in order to satisfy the power demand of the load 23.

[0033] (b) The first SOC or the second SOC is equal to or lower than a predetermined specified percentage. The specified percentage is, for example, 20%. The requirement (b) is for determining whether the first SOC or the second SOC may become 0% due to discharge from the first battery 14A and the second battery 14B.

[0034] (c) The current time is included in a predetermined specific time period. The specific time period is a time period that is predetermined as a time period during which the power demand of the load 23 is high. The specific time period is set as, for example, 9:00 AM to 2:00 PM. Therefore, the control unit 15 executes the remaining capacity ratio control, which will be described later, only during the specific time period during which the power demand of the load 23 is high. In this way, the requirement (c) is intended to determine whether the power demand of the load 23 is likely to be high.

[0035] (d) The power supply from the external power source 22 to the load 23 is cut off. When the power supply from the external power source 22 to the load 23 is interrupted, the first battery 14A and the second battery 14B must cover the power demand of the load 23. Therefore, the requirement (d) is intended to determine whether the amount of power discharged from the first battery 14A and the second battery 14B is likely to be large.

[0036] The control unit 15 starts remaining capacity ratio control when any one of the requirements (a) to (d) is satisfied. When the remaining capacity ratio control is started, the control unit 15 acquires the first remaining capacity, the second remaining capacity, the first discharge power, and the second discharge power. Then, the control unit 15 compares the value obtained by dividing the first remaining capacity by the first discharge power with the value obtained by dividing the second remaining capacity by the second discharge power. The control unit 15 repeatedly acquires a series of various values ​​and compares the values ​​at every predetermined control cycle. When any one of the requirements (a) to (d) is satisfied, the control unit 15 starts remaining capacity ratio control.

[0037] When the value obtained by dividing the first remaining capacity by the first discharge power is compared with the value obtained by dividing the second remaining capacity by the second discharge power, and the former is found to be smaller, the control unit 15 controls the first power conversion circuit 13A and the second power conversion circuit 13B so that the power discharged from the first battery 14A is smaller than the power discharged from the second battery 14B.

[0038] Specifically, the control unit 15 determines whether the power to be supplied from the power supply device 10 to the load 23 is equal to or less than the second discharge power of the second battery 14B. If this determination is positive, the control unit 15 controls the first power conversion circuit 13A so that the power discharged from the first battery 14A becomes zero. Furthermore, the control unit 15 controls the first power conversion circuit 13A so that the first battery 14A is discharged until the value obtained by dividing the second remaining capacity by the second discharge power becomes the same as the value obtained by dividing the first remaining capacity by the first discharge power. In addition, the control unit 15 controls the second power conversion circuit 13B so that all the required power is discharged from the second battery 14B to the load 23.

[0039] On the other hand, when the power to be supplied from the power supply device 10 to the load 23 exceeds the second discharge power of the second battery 14B, the control unit 15 controls the second power conversion circuit 13B so that the second battery 14B discharges at the second discharge power. At the same time, the control unit 15 controls the first power conversion circuit 13A so that the difference obtained by subtracting the second discharge power from the power to be supplied from the power supply device 10 to the load 23 is discharged from the first battery 14A.

[0040] When the value obtained by dividing the first remaining capacity by the first discharge power is compared with the value obtained by dividing the second remaining capacity by the second discharge power, and the latter is found to be smaller, the control unit 15 controls the second power conversion circuit 13B and the first power conversion circuit 13A so that the power discharged from the second battery 14B is smaller than the power discharged from the first battery 14A.

[0041] Specifically, the control unit 15 determines whether the power to be supplied from the power supply device 10 to the load 23 is equal to or less than the first discharge power of the first battery 14A. If this determination is positive, the control unit 15 controls the second power conversion circuit 13B so that the power discharged from the second battery 14B becomes zero. Furthermore, the control unit 15 controls the second power conversion circuit 13B so that the second battery 14B is discharged until the value obtained by dividing the first remaining capacity by the first discharge power becomes the same as the value obtained by dividing the second remaining capacity by the second discharge power. In addition, the control unit 15 controls the first power conversion circuit 13A so that all the required power is discharged from the first battery 14A to the load 23.

[0042] On the other hand, when the power to be supplied from the power supply device 10 to the load 23 exceeds the first discharge power of the first battery 14A, the control unit 15 controls the first power conversion circuit 13A so that the first battery 14A discharges at the first discharge power. At the same time, the control unit 15 controls the second power conversion circuit 13B so that the difference obtained by subtracting the first discharge power from the power to be supplied from the power supply device 10 to the load 23 is discharged from the second battery 14B.

[0043] When the control unit 15 controls the first power conversion circuit 13A and the second power conversion circuit 13B as described above, the difference between the value obtained by dividing the first remaining capacity by the first discharge power and the value obtained by dividing the second remaining capacity by the second discharge power gradually decreases. When the value obtained by dividing the first remaining capacity by the first discharge power matches the value obtained by dividing the second remaining capacity by the second discharge power, the ratio of the first remaining capacity to the second remaining capacity matches the ratio of the first discharge power to the second discharge power. Therefore, the control of the first power conversion circuit 13A and the second power conversion circuit 13B described above is control for bringing the ratio of the first remaining capacity to the second remaining capacity closer to the ratio of the first discharge power to the second discharge power. Note that "matching" allows for some degree of error.

[0044] After the value obtained by dividing the first remaining capacity by the first discharge power matches the value obtained by dividing the second remaining capacity by the second discharge power, the control unit 15 controls the first power conversion circuit 13A and the second power conversion circuit 13B to maintain this state. That is, the control unit 15 controls the first power conversion circuit 13A and the second power conversion circuit 13B so that the ratio of the power discharged from the first battery 14A to the power discharged from the second battery 14B matches the ratio of the first remaining capacity to the second remaining capacity. As a result, after this, the difference between the value obtained by dividing the first remaining capacity by the first discharge power and the value obtained by dividing the second remaining capacity by the second discharge power remains approximately zero.

[0045] An example of remaining capacity ratio control will be described with reference to Figs. 2 to 4, illustrating specific numerical values. In the example shown in Figs. 2 to 4, the first discharge power of the first battery 14A is 1 kW. The first capacity of the first battery 14A is 1 kWh. The first remaining capacity of the first battery 14A is 2 kWh. Furthermore, the second discharge power of the second battery 14B is 2 kW. The second capacity of the second battery 14B is 3 kWh. The second remaining capacity is 3 kWh.

[0046] In this case, it is assumed that remaining capacity ratio control is executed. The value obtained by dividing the first remaining capacity by the first discharge power is 2 h (hours). The value obtained by dividing the second remaining capacity by the second discharge power is 1.5 h (hours). Since the latter is smaller, the control unit 15 controls the second power conversion circuit 13B and the first power conversion circuit 13A so that the power discharged from the second battery 14B is smaller than the power discharged from the first battery 14A.

[0047] Next, the control unit 15 determines whether the power to be supplied from the power supply device 10 to the load 23 is equal to or less than the first discharge power of the first battery 14A. If this determination is affirmative, the control unit 15 controls the second power conversion circuit 13B so that the power discharged from the second battery 14B becomes zero. The control unit 15 also controls the second power conversion circuit 13B so that the second battery 14B is discharged until the value obtained by dividing the first remaining capacity by the first discharge power becomes equal to the value obtained by dividing the second remaining capacity by the second discharge power. Therefore, the control unit 15 discharges the first battery 14A so that the value obtained by dividing the first remaining capacity by the first discharge power becomes 1.5 h. At this time, the control unit 15 controls the first power conversion circuit 13A so that all the required power is discharged from the first battery 14A to the load 23.

[0048] Next, as shown in Fig. 3, it is assumed that the value obtained by dividing the first remaining capacity by the first discharge power matches the value obtained by dividing the second remaining capacity by the second discharge power. As shown in Fig. 4, the control unit 15 controls the first power conversion circuit 13A and the second power conversion circuit 13B so that this state is maintained. The ratio of the first remaining capacity to the second remaining capacity is 1:2. Therefore, the control unit 15 controls the first power conversion circuit 13A and the second power conversion circuit 13B so that the ratio of the power discharged from the first battery 14A to the power discharged from the second battery 14B is maintained at 1:2.

[0049] (Air volume ratio control) The free capacity ratio control performed by the control unit 15 will be described below. The free capacity ratio control is the following control. The free capacity ratio control is applied to a power supply device including first to n-th batteries, first to n-th power conversion circuits corresponding to the first to n-th batteries, respectively, for converting charge / discharge power, and a control unit capable of controlling the first to n-th power conversion circuits (where n is an integer of 2 or more). In this power supply device, the rated power that can be charged to the first to n-th batteries is defined as the first to n-th charge powers. The amounts of power that can be stored in the first to n-th batteries are defined as the first to n-th capacities, respectively. The differences between the first to n-th capacities and the amounts of power stored in the corresponding first to n-th batteries are defined as the first to n-th free capacities, respectively. The free capacity ratio control is control performed by the control unit on the first to n-th power conversion circuits so that the ratios of the first to n-th free capacities approach the ratios of the first to n-th charge powers. More specifically, the free capacity ratio control performs the following control. Let x be any integer between 1 and n, and let y be any integer between 1 and n, different from x. In the free capacity ratio control, when the value obtained by dividing the xth free capacity by the xth charging power is smaller than the value obtained by dividing the yth free capacity by the yth charging power, the control unit 15 controls the xth power conversion circuit and the yth power conversion circuit so that the power charged to the xth battery is smaller than the power charged to the yth battery.

[0050] In this embodiment, n is 2. In addition, in this embodiment, the ratio between the first capacity and the second capacity is 2:3. And the ratio between the first charging power and the second charging power is 1:2. In other words, neither the ratio between the first capacity and the second capacity nor the ratio between the first charging power and the second charging power is 1:1. That is, the free capacity ratio control in this embodiment refers to control performed by the control unit 15 on the first power conversion circuit 13A and the second power conversion circuit 13B so that the ratio between the first free capacity of the first battery 14A and the second free capacity of the second battery 14B approaches the ratio between the first charging power of the first battery 14A and the second discharging power of the second battery 14B. The free capacity ratio control will be specifically described below.

[0051] The control unit 15 determines whether or not the conditions for executing the air capacity ratio control are satisfied at each predetermined control period while the first battery 14A and the second battery 14B are being charged by the solar panel 20. The conditions for executing the air capacity ratio control are that one or more of the following requirements (e) to (h) are satisfied:

[0052] (e) The power supplied from the solar panel 20 is greater than a predetermined specified power. The specified power is set to, for example, a value slightly smaller than the sum of the first charging power of the first battery 14A and the second charging power of the second battery 14B. That is, requirement (e) is for determining a situation in which both the first battery 14A and the second battery 14B are charged with approximately the maximum charging power.

[0053] (f) The first SOC or the second SOC is equal to or greater than a predetermined specified percentage. The specified percentage is, for example, 80%. The requirement (f) is for determining whether there is a high possibility that the first SOC or the second SOC will reach 100% as a result of charging from the first battery 14A and the second battery 14B.

[0054] (g) The current time is included in a predetermined specific time period. The specific time period is a time period that is predetermined as a time period during which the power supply from the solar panel 20 is large. The specific time period is set as, for example, 11:00 AM to 2:00 PM. Therefore, the control unit 15 executes the empty capacity ratio control, which will be described later, only during the time period during which the power supply from the solar panel 20 is large. In this way, the requirement (g) is intended to determine whether the power supply from the solar panel 20 is likely to be large.

[0055] (h) The amount of power that the external power source 22 can supply is equal to or greater than the amount of power required by the load 23. When the amount of power that can be supplied from the external power source 22 is equal to or greater than the amount of power required by the load 23, there is little need for the first battery 14A and the second battery 14B to cover the power demand of the load 23. In other words, there is a high possibility that the first battery 14A and the second battery 14B will be charged. Therefore, the requirement (h) is intended to determine that there is a high possibility that the amount of power that is charged from the solar panel 20 to the first battery 14A and the second battery 14B will be large.

[0056] When any one of the above requirements (e) to (h) is satisfied, the control unit 15 starts the free space ratio control. When the free space ratio control starts, the control unit 15 acquires the first free space, the second free space, the first charging power, and the second charging power. Then, the control unit 15 compares the value obtained by dividing the first free space by the first charging power with the value obtained by dividing the second free space by the second charging power. The control unit 15 repeatedly acquires a series of various values ​​and compares the values ​​at every predetermined control cycle.

[0057] When the value obtained by dividing the first free capacity by the first charging power is compared with the value obtained by dividing the second free capacity by the second charging power, and the former is found to be smaller, the control unit 15 controls the first power conversion circuit 13A and the second power conversion circuit 13B so that the power charged to the first battery 14A is smaller than the power charged to the second battery 14B.

[0058] Specifically, the control unit 15 determines whether the power supplied from the solar panel 20 to each battery is equal to or less than the second charging power of the second battery 14B. If this determination is positive, the control unit 15 controls the first power conversion circuit 13A so that the power charged to the first battery 14A becomes zero. In addition, the control unit 15 controls the second power conversion circuit 13B so that all of the power supplied from the solar panel 20 to each battery is charged to the second battery 14B.

[0059] On the other hand, when the power supplied from the solar panel 20 to each battery exceeds the second charging power of the second battery 14B, the control unit 15 controls the second power conversion circuit 13B so that the second battery 14B is charged with the second charging power. At the same time, the control unit 15 controls the first power conversion circuit 13A so that the difference obtained by subtracting the second charging power from the power supplied from the solar panel 20 is charged to the first battery 14A.

[0060] When the value obtained by dividing the first free capacity by the first charging power is compared with the value obtained by dividing the second free capacity by the second charging power, and the latter is found to be smaller, the control unit 15 controls the second power conversion circuit 13B and the first power conversion circuit 13A so that the power charged to the second battery 14B is smaller than the power charged to the first battery 14A.

[0061] Specifically, the control unit 15 determines whether the power supplied from the solar panel 20 to each battery is equal to or less than the first charging power of the first battery 14A. If this determination is positive, the control unit 15 controls the second power conversion circuit 13B so that the power charged to the second battery 14B becomes zero. In addition, the control unit 15 controls the first power conversion circuit 13A so that all of the power supplied from the solar panel 20 to each battery is charged to the first battery 14A.

[0062] On the other hand, when the power supplied from the solar panel 20 to each battery exceeds the first charging power of the first battery 14A, the control unit 15 controls the first power conversion circuit 13A so that the first battery 14A is charged with the first charging power. At the same time, the control unit 15 controls the second power conversion circuit 13B so that the difference obtained by subtracting the first charging power from the power supplied from the solar panel 20 is charged to the second battery 14B.

[0063] When the control unit 15 controls the first power conversion circuit 13A and the second power conversion circuit 13B as described above, the difference between the value obtained by dividing the first free capacity by the first charging power and the value obtained by dividing the second free capacity by the second charging power gradually decreases. When the value obtained by dividing the first free capacity by the first charging power matches the value obtained by dividing the second free capacity by the second charging power, the ratio of the first free capacity to the second free capacity matches the ratio of the first charging power to the second charging power. Therefore, the above-described control of the first power conversion circuit 13A and the second power conversion circuit 13B is control for bringing the ratio of the first free capacity to the second free capacity closer to the ratio of the first charging power to the second charging power.

[0064] After the value obtained by dividing the first free capacity by the first charging power matches the value obtained by dividing the second free capacity by the second charging power, the control unit 15 controls the first power conversion circuit 13A and the second power conversion circuit 13B to maintain this state. In other words, the control unit 15 controls the first power conversion circuit 13A and the second power conversion circuit 13B so that the ratio of the power charged to the first battery 14A to the power charged to the second battery 14B matches the ratio of the first free capacity to the second free capacity. As a result, after this, the difference between the value obtained by dividing the first free capacity by the first charging power and the value obtained by dividing the second free capacity by the second charging power remains approximately zero.

[0065] (Effects of remaining capacity ratio control) (1) In the above embodiment, the control unit 15 can execute remaining capacity ratio control, which controls the first power conversion circuit 13A and the second power conversion circuit 13B so that the ratio between the first remaining capacity and the second remaining capacity approaches the ratio between the first discharge power and the second discharge power. Here, let us assume that, as a result of executing remaining capacity ratio control, the ratio between the first remaining capacity and the second remaining capacity matches the ratio between the first discharge power and the second discharge power. Then, in this state, let us assume that the first battery 14A discharges at the first discharge power and the second battery 14B discharges at the second discharge power. Under such circumstances, the first remaining capacity of the first battery 14A and the second remaining capacity of the second battery 14B reach zero almost simultaneously. Therefore, it is unlikely that a situation will occur in which only one battery reaches zero first, preventing the other battery from supplying sufficient power to the load 23. Therefore, even if the first battery 14A and the second battery 14B differ in terms of the amount of storable power, discharge power, and other characteristics, appropriate discharge can be performed.

[0066] (2) In the above embodiment, the control unit 15 compares the value obtained by dividing the first remaining capacity by the first discharge power with the value obtained by dividing the second remaining capacity by the second discharge power. If the value obtained by dividing the first remaining capacity by the first discharge power is smaller, the control unit 15 controls the first power conversion circuit 13A so that the power discharged from the first battery 14A is as close to zero as possible. At the same time, the control unit 15 controls the second power conversion circuit 13B so that as much power as possible is discharged from the second battery 14B. As a result, the second remaining capacity decreases quickly, and the ratio between the first remaining capacity and the second remaining capacity quickly approaches the ratio between the first discharge power and the second discharge power. Therefore, the ratio between the first remaining capacity and the second remaining capacity quickly approaches the ratio between the first discharge power and the second discharge power.

[0067] (3) In the above embodiment, the control unit 15 executes the remaining capacity ratio control when the power demand of the load 23 is greater than a predetermined specified power. When the power demand of the load 23 is greater than the predetermined specified power, it is highly likely that both the first battery 14A and the second battery 14B must be discharged to approximately their maximum. In such a case, by executing the above-described remaining capacity ratio control, it is possible to use up the remaining capacities of both the first battery 14A and the second battery 14B.

[0068] (4) In the above embodiment, when the first SOC or the second SOC becomes equal to or lower than a predetermined ratio, the control unit 15 executes remaining capacity ratio control. When the first SOC or the second SOC becomes equal to or lower than the predetermined ratio, there is a significant possibility that the remaining capacity of the first battery 14A or the second battery 14B will become zero. In such a case, executing remaining capacity ratio control can prevent the SOC of only one battery from becoming zero. Furthermore, since the number of times that the SOC of each battery becomes zero can be reduced, deterioration of each battery due to over-discharge can be prevented.

[0069] (5) In the above embodiment, the control unit 15 executes the remaining capacity ratio control only during a predetermined specific time period. If it is predicted that the power demand of the load 23 on the power supply device 10 will be high during that specific time period, the discharge power from each battery may be high during that specific time period. In other words, the above-mentioned time period is a suitable time period for executing the above-described remaining capacity ratio control to obtain the effect of fully using up the remaining capacities of both the first battery 14A and the second battery 14B.

[0070] (6) In the above embodiment, the control unit 15 executes the remaining capacity ratio control when the power supply from the external power source 22 to the load 23 is interrupted. During a power outage, the first battery 14A and the second battery 14B must meet the power demand of the load 23, and therefore, the discharge power of each battery is expected to increase. In other words, a power outage is a favorable situation for executing the above-described remaining capacity ratio control to obtain the effect of using up the remaining capacities of both the first battery 14A and the second battery 14B.

[0071] (Effects of air-to-air ratio control) (7) In the above embodiment, the control unit 15 can execute free space ratio control, which controls the first power conversion circuit 13A and the second power conversion circuit 13B so that the ratio between the first free space and the second free space approaches the ratio between the first charging power and the second charging power. Here, let's assume that, as a result of executing free space ratio control, the ratio between the first free space and the second free space matches the ratio between the first charging power and the second charging power. Then, in this state, let's assume that the first battery 14A is charged with the first charging power and the second battery 14B is charged with the second charging power. Under these circumstances, the first free space of the first battery 14A and the second free space of the second battery 14B become zero approximately simultaneously. That is, the first battery 14A and the second battery 14B become fully charged approximately simultaneously. Therefore, when one battery is fully charged and the other battery is not fully charged, the already fully charged battery is unlikely to be overcharged. Therefore, overcharging can be prevented to protect the batteries. Also, even if the first battery 14A and the second battery 14B differ in terms of the amount of electric energy that can be stored and the charging power, appropriate charging can be performed.

[0072] (8) In the above embodiment, the control unit 15 compares the value obtained by dividing the first free capacity by the first charging power with the value obtained by dividing the second free capacity by the second charging power. If the value obtained by dividing the first free capacity by the first charging power is smaller, the control unit 15 controls the first power conversion circuit 13A so that the power charged to the first battery 14A is as close to zero as possible. At the same time, the control unit 15 controls the second power conversion circuit 13B so that as much power as possible is charged to the second battery 14B. This causes the second free capacity to decrease quickly, and the ratio between the first free capacity and the second free capacity quickly approaches the ratio between the first charging power and the second charging power. Therefore, the ratio between the first free capacity and the second free capacity quickly approaches the ratio between the first charging power and the second charging power.

[0073] (9) In the above embodiment, the control unit 15 executes the air capacity ratio control when the power supplied from the solar panel 20 is greater than a predetermined specified power. When the power supplied from the solar panel 20 is greater than a predetermined specified power, it is highly likely that both the first battery 14A and the second battery 14B are being charged with substantially maximum charging power. In such a case, by executing the above-described air capacity ratio control, both the first battery 14A and the second battery 14B can be fully charged substantially simultaneously.

[0074] (10) In the above embodiment, when the first SOC or the second SOC becomes equal to or lower than a predetermined specified ratio, the control unit 15 executes the free capacity ratio control. When the first SOC or the second SOC becomes equal to or lower than the specified ratio, there is a high possibility that the first battery 14A or the second battery 14B will be fully charged. In such a case, executing the free capacity ratio control can prevent the SOC of only one battery from becoming 100%. This increases the possibility of preventing deterioration of each battery due to overcharging.

[0075] (11) In the above embodiment, the control unit 15 executes the free capacity ratio control only during a predetermined specific time period. If it is predicted that the power generated by the solar panel 20 will be large during that specific time period, the charging power for each battery may be large during that specific time period. In other words, the above-mentioned time period is suitable for executing the above-described free capacity ratio control to obtain the effect of fully charging both the first battery 14A and the second battery 14B approximately simultaneously.

[0076] (12) In the above embodiment, the control unit 15 executes the air capacity ratio control when the amount of power that the external power source 22 can supply is equal to or greater than the amount of power required by the load 23. When the external power source 22 is supplying a sufficient amount of power to the load 23, there is little need for the first battery 14A and the second battery 14B to supply power to the load 23. In other words, this is a favorable situation for charging each battery, and there is a considerable possibility that the power supplied to each battery will increase. In other words, the above situation is a favorable situation for executing the above-described air capacity ratio control to obtain the effect of fully charging both the first battery 14A and the second battery 14B approximately simultaneously.

[0077] <Example of change> The above-described embodiment and the following modified examples can be implemented in combination with each other to the extent that no technical contradiction occurs.

[0078] (Examples of changes to the overall configuration) The power supply device 10 may have three or more pairs of batteries and power conversion circuits corresponding to the batteries.

[0079] That is, when n is an integer equal to or greater than 2, power supply device 10 may include first to n-th batteries, first to n-th power conversion circuits that convert charging / discharging power for first to n-th batteries, and control unit 15 that can control first to n-th power conversion circuits. Note that, for example, first power conversion circuit 13A converts power corresponding to first battery 14A. The n-th power conversion circuit converts power corresponding to the n-th battery.

[0080] In this case, the amounts of power that the first to nth batteries can store are referred to as first to nth capacities, respectively. The amounts of power stored in the first to nth batteries are referred to as first to nth remaining capacities, respectively. The units of the first to nth capacities and the first to nth remaining capacities are, for example, Wh (watt-hours).

[0081] The rated powers that the first to n-th batteries can discharge are referred to as the first to n-th discharge powers, respectively. The maximum powers that can be charged into the first to n-th batteries are referred to as the first to n-th charge powers. The first to n-th discharge powers are the maximum powers that are output from the first to n-th power conversion circuits when the first to n-th batteries are discharged independently. The first to n-th charge powers are the maximum powers that are input to the first to n-th power conversion circuits when the first to n-th batteries are charged independently. The first to n-th discharge powers and the first to n-th charge powers are values ​​that change depending on operating conditions such as temperature, the rated values ​​of the corresponding power conversion circuits, etc. The first to n-th discharge powers and the first to n-th charge powers are expressed in units of, for example, W (watts).

[0082] The differences between the first to n-th capacities and the amounts of power stored in the corresponding first to n-th batteries are defined as the first to n-th available capacities, respectively. Therefore, the above embodiment illustrates the case where n is 2.

[0083] The power source that supplies power to the power supply device 10 is not limited to the solar panel 20. For example, a power source such as a wind power generator may be connected instead of or in addition to the solar panel 20. Furthermore, depending on the type of power source connected to the power supply device 10, the PV converter 11 may be omitted or another electrical circuit may be provided.

[0084] The first battery 14A and the second battery 14B may be charged from the external power source 22 via the inverter 12. The ratio between the first capacity and the second capacity and the ratio between the first discharge power and the second discharge power do not have to be 1:1. Also, the ratio between the first capacity and the second capacity and the ratio between the first charge power and the second charge power do not have to be 1:1.

[0085] At least one of the ratio between the first capacity and the second capacity and the ratio between the first discharge power and the second discharge power may be 1:1. Also, at least one of the ratio between the first capacity and the second capacity and the ratio between the first charge power and the second charge power may be 1:1.

[0086] The control unit 15 may not be able to calculate or acquire the SOC of each battery. The control unit 15 may not be able to calculate or acquire the SOH of each battery. Even in this case, the effect described in (1) can be obtained. The method for calculating the SOC and SOH is not limited to the example of the above embodiment. The SOC or SOH may be calculated by other known methods as long as remaining capacity ratio control and empty capacity ratio control can be executed.

[0087] The control unit 15 does not have to be able to acquire information on whether or not the power supply from the external power source 22 to the load 23 has been interrupted, i.e., whether or not a power outage has occurred. Even in this case, the effect described in (1) can be obtained.

[0088] It is optional whether the control unit 15 can switch between grid-connected operation and self-sustained operation. That is, only grid-connected operation or only self-sustained operation may be performed. If standalone operation is possible, the power supply device 10 does not need to be connected to the external power supply 22.

[0089] (Example of modification of remaining capacity ratio control) When the power supply device 10 has first to n-th batteries and first to n-th power conversion circuits, the control unit 15 only needs to be able to perform remaining capacity ratio control that controls the first to n-th power conversion circuits so that the ratios of the first to n-th remaining capacities approach the ratios of the first to n-th discharge powers.

[0090] For example, when n is 3, the control unit 15 performs the remaining capacity ratio control as follows: The execution conditions for the remaining capacity ratio control are the same as those in this embodiment. First, a first value obtained by dividing the first remaining capacity by the first discharge power is compared with a second value obtained by dividing the second remaining capacity by the second discharge power, and a third value obtained by dividing the third remaining capacity by the third discharge power. If the third value is found to be the smallest, for example, the control unit 15 controls the first to third power conversion circuits so that the power discharged from the third battery is smaller than the power discharged from the first battery and the second battery.

[0091] Specifically, first, the control unit 15 determines whether the power to be supplied from the power supply device 10 to the load 23 is equal to or less than the first discharge power of the first battery and the second discharge power of the second battery. If this determination is positive, the control unit 15 controls the third power conversion circuit so that the power discharged from the third battery becomes zero. Furthermore, the control unit 15 controls the first power conversion circuit and the second power conversion circuit so that the first battery and the second battery are discharged until the first value and the second value become equal to the third value. In addition, the control unit 15 controls the first power conversion circuit and the second power conversion circuit so that all the required power is discharged from the first battery and the second battery to the load 23.

[0092] When the control unit 15 controls the first to third power conversion circuits as described above, the difference between the first value, the second value, and the third value gradually decreases. When the first value, the second value, and the third value match, they match the ratio of the first remaining capacity to the second remaining capacity to the third remaining capacity, and the ratio of the first discharge power to the second discharge power to the third discharge power.

[0093] After the first value, the second value, and the third value match, the control unit 15 controls the first to third power conversion circuits so that this state is maintained. That is, the control unit 15 controls the first to third power conversion circuits so that the ratio of the power discharged from the first battery, the power discharged from the second battery, and the power discharged from the third battery matches the ratio of the first remaining capacity, the second remaining capacity, and the third remaining capacity. As a result, the difference between the first value, the second value, and the third value is maintained at approximately zero thereafter.

[0094] The conditions for executing the remaining capacity ratio control are not limited to those described in the above embodiment. Only some of the requirements (a) to (d) above may be set as requirements, or requirements other than (a) to (d) above may be set as requirements. Furthermore, the conditions for executing the remaining capacity ratio control may be set as the satisfaction of two or more of the requirements.

[0095] The remaining capacity ratio control may be performed at a timing selected by the user through a user operation. Even if the conditions for executing the remaining capacity ratio control are met and the control unit 15 is currently executing the remaining capacity ratio control, the user may be able to stop the remaining capacity ratio control at any timing.

[0096] The control unit 15 may always execute remaining capacity ratio control during discharging. The control unit 15 may predict a time period during which the power demand of the load 23 on the power supply device 10 will be high, based on the past operation history of the power supply device 10, etc. In this case, the control unit 15 may execute remaining capacity ratio control only during the time period during which the power demand of the load 23 predicted by the control unit 15 will be high. Note that the time period during which the power demand of the load 23 predicted by the control unit 15 will be high can also be considered a predetermined specific time period.

[0097] The control unit 15 may be configured to receive weather warning information, power outage prediction information, etc., via wireless communication with an external server, etc. In this case, the control unit 15 may execute remaining capacity ratio control during a time period when a power outage is predicted. Note that the time period when a power outage is predicted can also be considered a predetermined specific time period.

[0098] In this way, it is preferable to design the system so that remaining capacity ratio control is executed in a situation where the power demand from the load 23 is predicted to be large. When the power supply device 10 has first to n-th batteries, the target values ​​for the amount of power to be stored in the first to n-th batteries are defined as first to n-th target remaining capacities. The absolute values ​​of the differences between the first to n-th remaining capacities and the first to n-th target remaining capacities are defined as first to n-th difference values, respectively. Furthermore, x is an arbitrary integer between 1 and n, and y is an arbitrary integer between 1 and n, different from x.

[0099] In remaining capacity ratio control, the control unit 15 may set the first to nth target remaining capacities so that the ratios of the first to nth remaining capacities approach the ratios of the first to nth discharge powers. That is, when the xth difference value is greater than the yth difference value, the control unit 15 may control the xth power conversion circuit and the yth power conversion circuit so that the power discharged from the xth battery is greater than the power discharged from the yth battery.

[0100] For example, in the above embodiment, the control unit 15 may set a first target remaining capacity for the first battery 14A and a second target remaining capacity for the second battery 14B. For example, the first target remaining capacity and the second target remaining capacity may be set so that the ratio between the first remaining capacity of the first battery 14A and the second remaining capacity of the second battery 14B is equal to the ratio between the first discharge power and the second discharge power. In other words, the target remaining capacities may be set so that the ratio between the first target remaining capacity and the second target remaining capacity is equal to the ratio between the first discharge power and the second discharge power. In this case, the control unit 15 calculates a first difference value, which is the difference between the first target remaining capacity and the first remaining capacity, and a second difference value, which is the difference between the second target remaining capacity and the second remaining capacity. Then, the control unit 15 compares the first difference value with the second difference value. Next, the control unit 15 controls each power conversion circuit so that the power discharged from the battery with the larger difference value is greater than the power discharged from the battery with the smaller difference value. Even in this case, if the battery with the larger difference value has a larger value obtained by dividing the remaining capacity of that battery by the discharge power, the above control is remaining capacity ratio control. Note that the first target remaining capacity and the second target remaining capacity do not need to be specific values. For example, the first target remaining capacity and the second target remaining capacity may be within a range of ±10% of the power amount value that makes the ratio between the first remaining capacity and the second remaining capacity the same as the ratio between the first discharge power and the second discharge power.

[0101] When the power supply device 10 has first to n-th batteries, the series of controls in the above embodiment can be applied when at least one of the ratio between the x-th capacity and the y-th capacity and the ratio between the x-th discharge power and the y-th discharge power is not 1:1. Note that it is sufficient that there is at least one pair of x and y.

[0102] When power supply device 10 has first to n-th batteries, x is an arbitrary integer between 1 and n, and y is an arbitrary integer between 1 and n, different from x. In this case, control unit 15 may control the x-th power conversion circuit in the remaining capacity ratio control so that the power discharged from the x-th battery increases as the value obtained by dividing the x-th remaining capacity by the x-th discharge power increases. As a result, even when power supply device 10 has n batteries, the ratio of the first to n-th remaining capacities quickly approaches the ratio of the first to n-th discharge powers.

[0103] When the power supply device 10 has first to n-th batteries, x is an arbitrary integer between 1 and n, and y is an arbitrary integer between 1 and n, different from x. In this case, in the remaining capacity ratio control, if the value obtained by dividing the x-th remaining capacity by the x-th discharge power is smaller than the value obtained by dividing the y-th remaining capacity by the y-th discharge power, the control unit 15 may execute the following control. That is, the control unit 15 controls the x-th power conversion circuit so that the power discharged from the x-th battery becomes zero. The control unit 15 also controls the y-th power conversion circuit so that the y-th battery is discharged until the value obtained by dividing the x-th remaining capacity by the x-th discharge power becomes the same as the value obtained by dividing the y-th remaining capacity by the y-th discharge power. As a result, even when the power supply device 10 has n batteries, the ratio of the first to n-th remaining capacities quickly approaches the ratio of the first to n-th discharge powers.

[0104] When the power supply device 10 has first to n-th batteries, x is an arbitrary integer between 1 and n, and y is an arbitrary integer between 1 and n, different from x. In this case, in the remaining capacity ratio control, if the value obtained by dividing the x-th remaining capacity by the x-th discharge power is smaller than the value obtained by dividing the y-th remaining capacity by the y-th discharge power, the control unit 15 may execute the following control. That is, the control unit 15 does not need to control the x-th power conversion circuit so that the power discharged from the x-th battery becomes zero. For example, in the above embodiment, when the value obtained by dividing the first remaining capacity by the first discharge power is compared with the value obtained by dividing the second remaining capacity by the second discharge power, the following design may be performed.

[0105] When the former is smaller and the power to be supplied to the load 23 is equal to or less than the second discharge power of the second battery 14B, the control unit 15 does not need to control the first power conversion circuit 13A so that the amount of power discharged from the first battery 14A becomes zero as remaining capacity ratio control.

[0106] In this case, the effect described in (1) can be obtained by the control unit 15 controlling the first power conversion circuit 13A and the second power conversion circuit 13B so that the power discharged from the first battery 14A is smaller than the power discharged from the second battery 14B.

[0107] When the latter is smaller and the power to be supplied to the load 23 is equal to or less than the first discharge power of the first battery 14A, the control unit 15 does not need to control the second power conversion circuit 13B so that the amount of power discharged from the second battery 14B becomes zero as remaining capacity ratio control.

[0108] In this case, the effect described in (1) can be obtained by the control unit 15 controlling the first power conversion circuit 13A and the second power conversion circuit 13B so that the power discharged from the second battery 14B is smaller than the power discharged from the first battery 14A.

[0109] Even if the power supply device 10 has three or more batteries and corresponding power conversion circuits, the control unit 15 can perform remaining capacity ratio control if any two batteries in any combination among the multiple batteries have different remaining capacities or discharge powers.

[0110] For example, the power supply device 10 may include a third battery and a third power conversion circuit having a third remaining capacity and a third discharge power. The amount of power stored in the third battery is defined as the third remaining capacity. The unit of the third remaining capacity is, for example, Wh (watt-hours). The rated power of the third battery via the third power conversion circuit is defined as the third discharge power. The unit of the third discharge power is, for example, W (watts). Furthermore, it is assumed that, among the three batteries, the ratio between the first discharge power and the third discharge power is not 1:1. In this case, the power supply device 10 may be designed to execute the remaining capacity ratio control only for the first battery and the third battery.

[0111] Alternatively, in this case, the control unit 15 can execute remaining capacity ratio control to control the first power conversion circuit 13A, the second power conversion circuit 13B, and the third power conversion circuit so that the ratio of the first remaining capacity, the second remaining capacity, and the third remaining capacity approaches the ratio of the first discharge power, the second discharge power, and the third discharge power. That is, the control unit 15 may be designed to control each power conversion circuit so that the power discharged from the battery with the smallest value obtained by comparing the value obtained by dividing the first remaining capacity by the first discharge power, the value obtained by dividing the second remaining capacity by the second discharge power, and the value obtained by dividing the third remaining capacity by the third discharge power is smaller than the power discharged from the other batteries.

[0112] (Example of changes to air volume ratio control) When the power supply device 10 has n batteries and n power conversion circuits, the control unit 15 only needs to be able to perform remaining capacity ratio control, which controls the first to nth power conversion circuits so that the ratios of the first to nth free capacities approach the ratios of the first to nth charged powers.

[0113] The conditions for executing the air capacity ratio control are not limited to those described in the above embodiment. Only some of the requirements (e) to (h) may be set as requirements, or requirements other than (e) to (h) may be set as requirements. Furthermore, the conditions for executing the air capacity ratio control may be set as the satisfaction of two or more of the requirements.

[0114] The empty capacity ratio control may be performed at a timing selected by the user through a user operation. Even when the conditions for executing the air capacity ratio control are met and the control unit 15 is currently executing the air capacity ratio control, the user may be able to stop the air capacity ratio control at any timing.

[0115] The control unit 15 may always execute the air capacity ratio control during charging. Furthermore, even if the first SOC or the second SOC is equal to or greater than a predetermined specified ratio, the control unit 15 may not execute the air capacity ratio control. The control unit 15 may not predetermine the time period during which the air capacity ratio control is executed. Even if the external power source 22 can supply an amount of power equal to or greater than the requested amount of power, the control unit 15 may not execute the air capacity ratio control.

[0116] Based on the past operation history of the power supply device 10, the control unit 15 may predict a time period during which the amount of generated power supplied from the solar panel 20 to the power supply device 10 will be large. In this case, the control unit 15 may execute the air capacity ratio control only during the time period during which the power supply from the solar panel 20 predicted by the control unit 15 will be large. Note that the time period during which the power supply from the solar panel 20 predicted by the control unit 15 will be large can also be considered a predetermined specific time period.

[0117] The control unit 15 may be configured to receive weather warning information, power outage prediction information, etc., via wireless communication with an external server or the like. In this case, the control unit 15 may charge each battery in advance during a time period before a power outage is predicted. At that time, the control unit 15 may execute empty capacity ratio control. Note that the time period before a power outage is predicted can also be considered a predetermined specific time period.

[0118] In this way, it is preferable to design the system so that the air capacity ratio control is executed in a situation where the supply of generated power from the solar panel 20 is predicted to increase. When the power supply device 10 has first to n-th batteries, the target values ​​of the differences between the first to n-th capacities and the amounts of power that the corresponding first to n-th batteries should store are defined as first to n-th target available capacities, respectively. The absolute values ​​of the differences between the first to n-th available capacities and the first to n-th target available capacities are defined as first to n-th difference values, respectively. Furthermore, x is an arbitrary integer between 1 and n, and y is an arbitrary integer between 1 and n, different from x.

[0119] In the free space ratio control, the control unit 15 may set the first to nth target free capacities so that the ratios of the first to nth free capacities approach the ratios of the first to nth charging powers. That is, when the xth difference value is greater than the yth difference value, the control unit 15 may control the xth power conversion circuit and the yth power conversion circuit so that the power charged to the xth battery is greater than the power charged to the yth battery.

[0120] For example, in the above embodiment, the control unit 15 may set a first target free capacity for the first battery 14A and a second target free capacity for the second battery 14B. For example, the first target free capacity and the second target free capacity may be set so that the ratio between the first free capacity of the first battery 14A and the second free capacity of the second battery 14B is equal to the ratio between the first charging power and the second charging power. In other words, the target free capacities may be set so that the ratio between the first target free capacity and the second target free capacity is equal to the ratio between the first charging power and the second charging power. In this case, the control unit 15 calculates a first difference value, which is the difference between the first target free capacity and the first free capacity, and a second difference value, which is the difference between the second target free capacity and the second free capacity. Then, the control unit 15 compares the first difference value with the second difference value. Next, the control unit 15 controls each power conversion circuit so that the power charged to the battery with the larger difference value is greater than the power charged to the battery with the smaller difference value. Even in this case, if the battery with the larger difference value has a larger value obtained by dividing the free capacity of that battery by the charging power, the above control is free capacity ratio control. Note that the first target free capacity and the second target free capacity do not need to be specific values. For example, the first target free capacity and the second target free capacity may be within a range of ±10% of the power amount value that makes the ratio between the first free capacity and the second free capacity the same as the ratio between the first charging power and the second charging power.

[0121] When the power supply device 10 has first to nth batteries, the series of controls described in the above embodiment can be applied when at least one of the ratio between the xth capacity and the yth capacity and the ratio between the xth charging power and the yth charging power is not 1:1. Note that it is sufficient that there is at least one pair of x and y.

[0122] When the power supply device 10 has first to n-th batteries, x is an arbitrary integer between 1 and n, and y is an arbitrary integer between 1 and n, different from x. In this case, the control unit 15 may control the x-th power conversion circuit in the free capacity ratio control so that the power charged to the x-th battery increases as the value obtained by dividing the x-th free capacity by the x-th charging power increases. As a result, even when the power supply device 10 has n batteries, the ratio of the first to n-th free capacities quickly approaches the ratio of the first to n-th charging powers.

[0123] When the power supply device 10 has first to n-th batteries, x is an arbitrary integer between 1 and n, and y is an arbitrary integer between 1 and n, different from x. In this case, in the free capacity ratio control, if the value obtained by dividing the x-th free capacity by the x-th charging power is smaller than the value obtained by dividing the y-th free capacity by the y-th charging power, the control unit 15 may execute the following control. That is, the control unit 15 controls the x-th power conversion circuit so that the power charged to the x-th battery becomes zero. The control unit 15 also controls the y-th power conversion circuit so that the y-th battery is charged until the value obtained by dividing the x-th free capacity by the x-th charging power becomes the same as the value obtained by dividing the y-th free capacity by the y-th charging power. As a result, even when the power supply device 10 has n batteries, the ratio of the first to n-th free capacities quickly approaches the ratio of the first to n-th charging powers.

[0124] When the power supply device 10 has first to n-th batteries, x is an arbitrary integer between 1 and n, and y is an arbitrary integer between 1 and n, different from x. In this case, in the free capacity ratio control, if the value obtained by dividing the x-th free capacity by the x-th charging power is smaller than the value obtained by dividing the y-th free capacity by the y-th charging power, the control unit 15 may execute the following control. That is, the control unit 15 does not need to control the x-th power conversion circuit so that the power charged to the x-th battery becomes zero. For example, in the above embodiment, when the value obtained by dividing the first free capacity by the first charging power is compared with the value obtained by dividing the second free capacity by the second charging power, the following design may be performed.

[0125] When the former is smaller and the power supplied from the solar panel 20 is equal to or less than the second charging power of the second battery 14B, the control unit 15 does not need to control the first power conversion circuit 13A as an empty capacity ratio control so that the amount of power charged to the first battery 14A becomes zero.

[0126] In this case, the effect described in (7) can be obtained by the control unit 15 controlling the first power conversion circuit 13A and the second power conversion circuit 13B so that the power charged to the first battery 14A is smaller than the power charged to the second battery 14B.

[0127] When the latter is smaller and the power supplied from the solar panel 20 is equal to or less than the first charging power of the first battery 14A, the control unit 15 does not need to control the second power conversion circuit 13B as an empty capacity ratio control so that the amount of power charged to the second battery 14B becomes zero.

[0128] In this case, the effect described in (7) can be obtained by the control unit 15 controlling the first power conversion circuit 13A and the second power conversion circuit 13B so that the power charged to the second battery 14B is smaller than the power charged to the first battery 14A.

[0129] Even if the power supply device 10 has three or more batteries and corresponding power conversion circuits, the control unit 15 can perform empty capacity ratio control if any two batteries in any combination among the multiple batteries have different free capacities or charging powers.

[0130] For example, the power supply device 10 may have a third battery and a third power conversion circuit having a third free capacity and a third charging power. The amount of power stored in the third battery is defined as the third free capacity. The unit of the third free capacity is, for example, Wh (watt-hours). The maximum power that can be charged into the third battery via the third power conversion circuit is defined as the third charging power. The unit of the third charging power is, for example, W (watts). Furthermore, it is assumed that, for example, the ratio between the first charging power and the third charging power of the three batteries is not 1:1. In this case, the power supply device 10 may be designed to execute free capacity ratio control only for the first battery and the third battery.

[0131] Alternatively, in this case, the control unit 15 can execute free capacity ratio control to control the first power conversion circuit 13A, the second power conversion circuit 13B, and the third power conversion circuit so that the ratio of the first free capacity, the second free capacity, and the third free capacity approaches the ratio of the first charging power, the second charging power, and the third charging power. That is, the control unit 15 may be designed to control each power conversion circuit so that the power charged to the battery with the smallest value obtained by comparing the value obtained by dividing the first free capacity by the first charging power, the value obtained by dividing the second free capacity by the second charging power, and the value obtained by dividing the third free capacity by the third charging power is smaller than the power charged to the other batteries.

[0132] <Additional Notes> The technical concepts that can be derived from the above-described embodiments and modifications will be described below. [1] When n is an integer of 2 or more, 1st to nth batteries, first to n-th power conversion circuits corresponding to the first to n-th batteries, respectively, for converting charge / discharge power; a control unit capable of controlling the first to nth power conversion circuits; Equipped with The amounts of electric power that can be stored in the first to nth batteries are defined as first to nth capacities, respectively; The rated powers that the first to nth batteries can discharge are defined as first to nth discharge powers, respectively; The amounts of power stored in the first to nth batteries are designated as first to nth remaining capacities, respectively; When x is an integer between 1 and n, and y is an integer between 1 and n, but different from x, At least one of the ratio between the xth capacity and the yth capacity and the ratio between the xth discharge power and the yth discharge power is not 1:1, The power supply device, wherein the control unit is capable of performing remaining capacity ratio control to control the first to nth power conversion circuits so that the ratios of the first to nth remaining capacities approach the ratios of the first to nth discharge powers.

[0133] [2] target values ​​of the amounts of power to be stored in the first to nth batteries are set as first to nth target remaining capacities, When the absolute values ​​of the differences between the first to n-th remaining capacities and the first to n-th target remaining capacities are respectively defined as first to n-th difference values, the control unit sets the first to nth target remaining capacities so that the ratios of the first to nth remaining capacities approach the ratios of the first to nth discharging powers in the remaining capacity ratio control; A power supply device as described in [1], which controls the xth power conversion circuit and the yth power conversion circuit so that the power discharged from the xth battery is greater than the power discharged from the yth battery when the xth difference value is greater than the yth difference value.

[0134] [3] The power supply device according to [1] or [2], wherein the control unit controls the xth power conversion circuit and the yth power conversion circuit so that the power discharged from the xth battery is less than the power discharged from the yth battery when the value obtained by dividing the xth remaining capacity by the xth discharge power is less than the value obtained by dividing the yth remaining capacity by the yth discharge power in the remaining capacity ratio control.

[0135] [4] In the remaining capacity ratio control, when a value obtained by dividing the x-th remaining capacity by the x-th discharge power is smaller than a value obtained by dividing the y-th remaining capacity by the y-th discharge power, The power supply device according to any one of [1] to [3], wherein the control unit controls the xth power conversion circuit so that the power discharged from the xth battery is zero, and controls the yth power conversion circuit so that the yth battery is discharged until the value obtained by dividing the xth remaining capacity by the xth discharge power becomes the same as the value obtained by dividing the yth remaining capacity by the yth discharge power.

[0136] [5] The power supply device according to any one of [1] to [4], wherein the control unit controls the xth power conversion circuit in the remaining capacity ratio control so that the larger the value obtained by dividing the xth remaining capacity by the xth discharge power, the larger the power discharged from the xth battery.

[0137] [6] The power supply device according to any one of [1] to [5], wherein the control unit executes the remaining capacity ratio control only during a predetermined specific time period.

[0138] [7] the first to nth batteries are capable of outputting power to a load; the load can be supplied with power from an external power source other than the first to nth batteries, When the power supply from the external power source to the load is interrupted, The power supply device according to any one of [1] to [6], wherein the control unit executes the remaining capacity ratio control.

[0139] [8] The power supply device according to any one of [1] to [7], wherein n is 2. [9] The amount of electric power that can be stored in the first battery is defined as a first capacity, The amount of electric power that can be stored in the second battery is defined as a second capacity, The SOC of the first battery is defined as a first SOC; When the SOC of the second battery is a second SOC, the first remaining capacity is calculated as a product of the first capacity and the first SOC, The power supply device according to [8], wherein the second remaining capacity is calculated as the product of the second capacity and the second SOC.

[0140]

[10] The SOC of the first battery is defined as a first SOC; When the SOC of the second battery is a second SOC, The power supply device according to [8] or [9], wherein the control unit executes the remaining capacity ratio control when the first SOC or the second SOC becomes equal to or lower than a predetermined specified ratio.

[0141]

[11] When n is an integer of 2 or more, 1st to nth batteries, first to n-th power conversion circuits corresponding to the first to n-th batteries, respectively, for converting charge / discharge power; a control unit capable of controlling the first to nth power conversion circuits; Equipped with The rated powers that can be charged into the first to nth batteries are defined as first to nth charging powers, The amounts of electric power that can be stored in the first to nth batteries are defined as first to nth capacities, respectively; The differences between the first to n-th capacities and the amounts of power stored in the corresponding first to n-th batteries are defined as first to n-th available capacities, respectively; When x is an integer between 1 and n, and y is an integer between 1 and n, but different from x, At least one of the ratio between the xth capacitance and the yth capacitance and the ratio between the xth charging power and the yth charging power is not 1:1, The power supply device, wherein the control unit is capable of executing free capacity ratio control that controls the first to nth power conversion circuits so that the ratios of the first to nth free capacities approach the ratios of the first to nth charging powers.

[0142]

[12] When the target values ​​of the differences between the first to n-th capacities and the amounts of power that should be stored in the corresponding first to n-th batteries are respectively set as first to n-th target available capacities, the absolute values ​​of the differences between the first to n-th free capacities and the first to n-th target free capacities are defined as first to n-th difference values, respectively; the control unit, in the free space ratio control, sets the first to nth target free spaces so that ratios of the first to nth free spaces approach ratios of the first to nth charging powers; A power supply device as described in

[11] , which controls the xth power conversion circuit and the yth power conversion circuit so that the power charged to the xth battery is greater than the power charged to the yth battery when the xth difference value is greater than the yth difference value.

[0143]

[13] The power supply device according to

[11] or

[12] , wherein the control unit controls the xth power conversion circuit and the yth power conversion circuit so that the power charged to the xth battery is less than the power charged to the yth battery when the value obtained by dividing the xth free capacity by the xth charging power is less than the value obtained by dividing the yth free capacity by the yth charging power in the free capacity ratio control.

[0144]

[14] In the free space ratio control, when a value obtained by dividing the xth free space by the xth charging power is smaller than a value obtained by dividing the yth free space by the yth charging power, The power supply device according to any one of

[11] to

[13] , wherein the control unit controls the xth power conversion circuit so that the power charged to the xth battery is zero, and controls the yth power conversion circuit so that the yth battery is charged until the value obtained by dividing the xth available capacity by the xth charging power becomes the same as the value obtained by dividing the yth available capacity by the yth charging power.

[0145]

[15] The power supply device according to any one of

[11] to

[14] , wherein the control unit controls the xth power conversion circuit in the free space ratio control so that the larger the value obtained by dividing the xth free space by the xth charging power, the larger the power charged to the xth battery.

[0146]

[16] The power supply device according to any one of

[11] to

[15] , wherein n is 2. [Explanation of symbols]

[0147] 10…Power supply device 11...PV converter 12...Inverter 13A...First power conversion circuit 14A…1st battery 13B...Second power conversion circuit 14B...Second battery 15...Control unit 20...Solar panels 21...Power lines 22…External power supply 23...Load

Claims

1. When n is an integer of 2 or more, first to n-th batteries; first to n-th power conversion circuits corresponding to the first to n-th batteries, respectively, for converting charge / discharge power; a control unit capable of controlling the first to n-th power conversion circuits; Equipped with The amounts of electric power that can be stored in the first to nth batteries are defined as first to nth capacities, respectively; The rated powers that the first to n-th batteries can discharge are defined as first to n-th discharge powers, respectively; The amounts of electric power stored in the first to nth batteries are designated as first to nth remaining capacities, respectively; When x is an integer of 1 or more and n or less, and y is an integer of 1 or more and n or less, other than x, At least one of the ratio between the xth capacity and the yth capacity and the ratio between the xth discharge power and the yth discharge power is not 1:1, the control unit is capable of executing remaining capacity ratio control for controlling the first to nth power conversion circuits so that the ratios of the first to nth remaining capacities approach the ratios of the first to nth discharge powers. power supply.

2. target values ​​of the amounts of power to be stored in the first to nth batteries are set as first to nth target remaining capacities, When the absolute values ​​of the differences between the first to n-th remaining capacities and the first to n-th target remaining capacities are respectively defined as first to n-th difference values, the control unit sets the first to nth target remaining capacities so that the ratios of the first to nth remaining capacities approach the ratios of the first to nth discharge powers in the remaining capacity ratio control; When the xth difference value is greater than the yth difference value, the xth power conversion circuit and the yth power conversion circuit are controlled so that the power discharged from the xth battery is greater than the power discharged from the yth battery. The power supply device of claim 1 .

3. When a value obtained by dividing an xth remaining capacity by the xth discharge power is smaller than a value obtained by dividing a yth remaining capacity by the yth discharge power, the control unit controls the xth power conversion circuit and the yth power conversion circuit so that the power discharged from the xth battery is smaller than the power discharged from the yth battery in the remaining capacity ratio control. The power supply device of claim 1 .

4. In the remaining capacity ratio control, when a value obtained by dividing the x-th remaining capacity by the x-th discharge power is smaller than a value obtained by dividing the y-th remaining capacity by the y-th discharge power, the control unit controls the xth power conversion circuit so that the power discharged from the xth battery becomes zero, and controls the yth power conversion circuit so that the yth battery is discharged until a value obtained by dividing the xth remaining capacity by the xth discharge power becomes equal to a value obtained by dividing the yth remaining capacity by the yth discharge power. The power supply device of claim 1 .

5. the control unit controls the xth power conversion circuit in the remaining capacity ratio control such that the power discharged from the xth battery increases as the value obtained by dividing the xth remaining capacity by the xth discharge power increases. The power supply device of claim 1 .

6. the control unit executes the remaining capacity ratio control only during a predetermined specific time period. The power supply device of claim 1 .

7. the first to n-th batteries are capable of outputting power to a load; the load can be supplied with power from an external power source other than the first to nth batteries, When the power supply from the external power source to the load is interrupted, The control unit executes the remaining capacity ratio control. The power supply device of claim 1 .

8. The n is 2 The power supply device of claim 1 .

9. The amount of electric power that can be stored in the first battery is defined as a first capacity, The amount of electric power that can be stored in the second battery is defined as a second capacity, The SOC of the first battery is defined as a first SOC, When the SOC of the second battery is a second SOC, the first remaining capacity is calculated as a product of the first capacity and the first SOC, The second remaining capacity is calculated by multiplying the second capacity by the second SOC.

9. The power supply device of claim 8.

10. The SOC of the first battery is defined as a first SOC, When the SOC of the second battery is a second SOC, When the first SOC or the second SOC becomes equal to or less than a predetermined specified ratio, the control unit executes the remaining capacity ratio control.

9. The power supply device of claim 8.

11. When n is an integer of 2 or more, first to n-th batteries; first to n-th power conversion circuits corresponding to the first to n-th batteries, respectively, for converting charge / discharge power; a control unit capable of controlling the first to n-th power conversion circuits; Equipped with The rated powers that can be charged into the first to nth batteries are defined as first to nth charging powers, The amounts of electric power that can be stored in the first to nth batteries are defined as first to nth capacities, respectively; The differences between the first to n-th capacities and the amounts of power stored in the corresponding first to n-th batteries are defined as first to n-th available capacities, respectively; When x is an integer of 1 or more and n or less, and y is an integer of 1 or more and n or less, other than x, At least one of the ratio between the xth capacity and the yth capacity and the ratio between the xth charging power and the yth charging power is not 1:1, the control unit is capable of executing free capacity ratio control for controlling the first to nth power conversion circuits so that the ratios of the first to nth free capacities approach the ratios of the first to nth charging powers. power supply.

12. When target values ​​of the differences between the first to n-th capacities and the amounts of power to be stored in the corresponding first to n-th batteries are respectively set to first to n-th target available capacities, absolute values ​​of the differences between the first to n-th free capacities and the first to n-th target free capacities are defined as first to n-th difference values, respectively; the control unit sets the first to nth target free capacities so that ratios of the first to nth free capacities approach ratios of the first to nth charging powers in the free capacity ratio control; When the xth difference value is greater than the yth difference value, the xth power conversion circuit and the yth power conversion circuit are controlled so that the power charged to the xth battery is greater than the power charged to the yth battery.

12. The power supply device of claim 11.

13. When a value obtained by dividing the xth free capacity by the xth charging power is smaller than a value obtained by dividing the yth free capacity by the yth charging power, the control unit controls the xth power conversion circuit and the yth power conversion circuit so that the power charged to the xth battery is smaller than the power charged to the yth battery in the free capacity ratio control.

12. The power supply device of claim 11.

14. In the free space ratio control, when a value obtained by dividing the xth free space by the xth charging power is smaller than a value obtained by dividing the yth free space by the yth charging power, the control unit controls the xth power conversion circuit so that the power charged to the xth battery becomes zero, and controls the yth power conversion circuit so that the yth battery is charged until a value obtained by dividing the xth free capacity by the xth charging power becomes equal to a value obtained by dividing the yth free capacity by the yth charging power.

12. The power supply device of claim 11.

15. the control unit controls the xth power conversion circuit in the free capacity ratio control so that the power charged to the xth battery increases as the value obtained by dividing the xth free capacity by the xth charging power increases.

12. The power supply device of claim 11.

16. The n is 2 12. The power supply device of claim 11.

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