Control unit, battery pack and power supply unit

Abstract

In the control device, battery pack and power supply device of the present invention, the battery remaining meter (14) estimates the battery remaining when the control unit (11) instructs to start supplying power to the driving power supply (Vcc) based on the battery voltage detected at the timing when the control unit (11) instructs to start supplying power to the driving power supply (Vcc). After the discharge of the rechargeable battery (BA) by the charging and discharging circuit (FC) is completed, the control unit (11) instructs to stop supplying power to the driving power supply (Vcc) at the timing when the battery voltage measured by the voltage measuring unit (13) stabilizes.

Description

Technical Field

[0001] The present invention relates to a control device for controlling the operation of a charge-discharge circuit for charging or discharging a rechargeable battery, and a battery pack and a power supply device including the control device. Background Art

[0002] Generally, electronic devices such as battery packs and power supply devices include a rechargeable battery and a battery remaining meter capable of estimating the remaining battery capacity of the rechargeable battery. The battery remaining meter detects a charging current flowing into the rechargeable battery when the rechargeable battery is charged and a discharging current output from the rechargeable battery when the rechargeable battery is discharged, and estimates the remaining battery capacity of the rechargeable battery based on the charging current and the discharging current.

[0003] However, compared to the OCV (Open Circuit Voltage) indicating the battery voltage when not charging or discharging, the battery voltage of the above-mentioned rechargeable battery becomes higher during the charging process and becomes lower during the discharging process. In addition, when charging and discharging are completed, the battery voltage of the rechargeable battery has the characteristic of gradually approaching the OCV. Here, the remaining battery capacity when the microcomputer is powered on by the electronic device is estimated based on the battery voltage. The battery voltage at this time is estimated based on the assumption that the OCV is the remaining battery capacity. That is, after charging or discharging the rechargeable battery, when the power of the microcomputer is cut off and then turned on again without waiting for time, there is a problem that the estimation accuracy of the remaining battery capacity deteriorates. Summary of the invention

[0004] An object of the present invention is to provide a control device, a battery pack, and a power supply device capable of improving the accuracy of estimating the remaining battery capacity of a rechargeable battery when an electronic device is started up from a stop (shutdown).

[0005] In order to achieve the above-mentioned purpose, the control device involved in the present embodiment is a control device that controls the operation of a charge-discharge circuit that performs charging or discharging of a rechargeable battery, including: a control unit, which is configured to control the power supply used to operate the charge-discharge circuit; a driving power supply, which provides driving power to the control unit; a voltage measuring unit, which is configured to measure the battery voltage of the rechargeable battery; and a battery remaining meter, which is configured to estimate the battery remaining amount of the rechargeable battery based on the battery voltage of the rechargeable battery measured by the voltage measuring unit, and the battery remaining meter estimates the battery remaining amount when the control unit instructs the start of supplying power to the driving power supply based on the battery voltage detected at the timing when the control unit instructs the start of supplying power to the driving power supply, and the control unit instructs to stop supplying power to the driving power supply at the timing when the battery voltage measured by the voltage measuring unit stabilizes after the discharge of the rechargeable battery by the charge-discharge circuit is completed. According to the above configuration, the control device according to the present aspect can improve the accuracy of estimating the remaining battery level of the rechargeable battery when starting up from a stop (shutdown).

[0006] In the control device involved in this method, the timing of the battery voltage stabilization is preferably the timing when the rate of change of the battery voltage per unit time becomes less than a predetermined threshold value. According to the above structure, the control device involved in this method can improve the estimation accuracy of the battery remaining capacity of the rechargeable battery when starting from a stop (shutdown).

[0007] In the control device of this embodiment, the timing when the battery voltage stabilizes is preferably the timing after a preset time has passed after the discharge is completed. According to the above structure, the control device of this embodiment can improve the estimation accuracy of the battery remaining amount of the rechargeable battery when starting from a stop (shutdown).

[0008] In the control device according to this aspect, the time is preferably 30 minutes to 2 hours. According to the above configuration, the control device according to this aspect can improve the accuracy of estimating the remaining battery level of the rechargeable battery when starting up from a stop (shutdown).

[0009] In the control device involved in this method, the timing of the battery voltage stabilization is preferably the timing when the battery voltage changes by only a specified value relative to the battery voltage at the end of discharge. According to the above structure, the control device involved in this method can improve the estimation accuracy of the battery remaining capacity of the rechargeable battery when starting from a stop (shutdown).

[0010] The battery pack according to the present embodiment includes the control device according to the present embodiment, the charging and discharging circuit, and the rechargeable battery. According to the above structure, the battery pack according to the present embodiment can improve the estimation accuracy of the remaining battery capacity of the rechargeable battery when starting from a stop (shutdown).

[0011] The power supply device of this embodiment includes the control device of this embodiment, the charging and discharging circuit and the rechargeable battery. According to the above structure, the power supply device of this embodiment can improve the estimation accuracy of the battery remaining amount of the rechargeable battery when starting from stopping (shutting down). BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 : is a circuit diagram showing a power supply device according to this embodiment.

[0013] Figure 2 is Figure 1 An example of a timing chart when the power supply device shown in the figure discharges the rechargeable battery and then charges the rechargeable battery.

[0014] Figure 3 It is a diagram for explaining the effects of the power supply device according to the present embodiment.

[0015] Figure 4 : is a circuit diagram showing a power supply device according to a modification. DETAILED DESCRIPTION

[0016] Hereinafter, a control device, a battery pack, and a power supply device according to an embodiment will be described with reference to the accompanying drawings. In addition, the present embodiment is not limited to the contents described below, and any changes can be made to implement the embodiment without changing the gist thereof. The drawings used in the description of the embodiments schematically illustrate the structural components, and sometimes, in order to deepen the understanding, parts are emphasized, enlarged, reduced, or omitted, etc., without correctly indicating the scale, shape, etc. of the structural components.

[0017] (structure)

[0018] Figure 1 2 is a circuit diagram showing a power supply device 1 according to the present embodiment. Figure 1 The power supply device 1 shown converts the power supplied from the external power supply PS into power that can be supplied to the load 2, and supplies the power to the load 2. In addition, the power supply device 1 supplies power to the load 2, and charges the rechargeable battery BA built into the power supply device 1 itself with the power. In addition, when the power from the external power supply PS stops due to a main reason such as a power outage, the power supply device 1 discharges the power stored in the rechargeable battery BA and supplies the power to the load 2. In addition, the power supply device 1 according to the present embodiment can charge the rechargeable battery BA while supplying power to the load 2.

[0019] like Figure 1 As shown, the power supply device 1 according to the present embodiment includes a voltage conversion converter CV and a battery pack BP. The battery pack BP includes the above-mentioned rechargeable battery BA, and includes a charge and discharge circuit FC and a control device CU. The voltage converter CV converts the power supplied from the external power supply PS into power that can be supplied to the load 2, and supplies it to the load 2. In addition, the voltage converter CV converts the power supplied from the external power supply PS into power that can be supplied to the rechargeable battery BA via the charge and discharge circuit FC, and supplies it to the rechargeable battery BA.

[0020] The charge and discharge circuit FC charges or discharges the rechargeable battery BA under the control of the control unit CU. The switch element Q1 and the switch element Q2 are provided in the charge and discharge circuit FC in this embodiment. The switch element Q1 is provided in the electrical path L1 between the voltage converter CV and the rechargeable battery BA. More specifically, the gate of the switch element Q1 is connected to the control unit 11 of the control unit CU described later. The drain of the switch element Q1 is connected to the voltage converter CV. The source of the switch element Q1 is connected to the rechargeable battery BA.

[0021] One end of the switching element Q2 is connected to the electrical path L2 between the switching element Q1 and the rechargeable battery BA, and the other end of the switching element Q2 is connected to the electrical path L3 between the voltage converter CV and the load 2. More specifically, the gate of the switching element Q2 is connected to the control unit 11 of the control device CU described later. The drain of the switching element Q2 (the one end) is connected to the electrical path L2. The source of the switching element Q2 (the other end) is connected to the electrical path L3.

[0022] The charge and discharge circuit FC in this embodiment performs the charging or discharging of the above-mentioned rechargeable battery BA by performing the on-off action of the above-mentioned switching element Q1 or the switching element Q2 under the control of the control device CU. For example, when charging the rechargeable battery BA, the charge and discharge circuit FC turns on the switching element Q1 and turns off the switching element Q2. As a result, power is supplied to the rechargeable battery BA from the external power supply PS via the voltage converter CV and the switching element Q1, and the power is stored in the rechargeable battery BA. In addition, when discharging the rechargeable battery BA, the charge and discharge circuit FC turns on the switching element Q2 and turns off the switching element Q1. As a result, power is supplied from the rechargeable battery BA to the load 2 via the switching element Q2.

[0023] The control unit CU controls the operation of the charging and discharging circuit FC. The control unit CU in this embodiment includes a control unit 11 , a switching element Q3 , a switching element Q4 , a regulator 12 , a voltage measuring unit 13 , and a battery level meter 14 .

[0024] The control unit 11 includes a predetermined processor as a hardware resource. The control unit 11 is connected to a driving power source Vcc that supplies power to the control unit 11 for driving the control unit 11. The control unit 11 is configured to control the power supply for operating the charging and discharging circuit FC. Figure 1 As shown, the control unit 11 in this embodiment is connected to the gates of the switching elements Q1 and Q2 of the charge and discharge circuit FC and the gate of the switching element Q4 of the control unit CU. The control unit 11 applies a predetermined gate voltage to the gates of the switching elements Q1, Q2, and Q4, thereby turning on the switching elements Q1, Q2, and Q4, respectively.

[0025] In addition, the control unit 11 turns on the switch element Q3 and the switch element Q4 at the timing of instructing to start supplying power to the driving power source Vcc (i.e., the timing of starting the above-mentioned power supply device 1), and turns off the switch element Q3 and the switch element Q4 at the timing of instructing to stop supplying power to the driving power source Vcc (i.e., the timing of stopping (shutting down) the above-mentioned power supply device 1). In addition, the control unit 11 can grasp the situation of the charging operation being performed by detecting the voltage Vreg output from the regulator 12. Here, the regulator 12 is connected in parallel with the switch element Q1 via the switch element Q3, and is configured to keep the power supplied from the voltage converter CV to the rechargeable battery BA constant.

[0026] Here, the gate of the switching element Q3 is connected to the drain of the switching element Q4. The drain of the switching element Q3 is connected to the electrical path L4 between the source of the switching element Q1 and the connection portion of the electrical path L2 to which the drain of the switching element Q2 is connected. The source of the switching element Q3 is connected to the regulator 12. As described above, the gate of the switching element Q4 is connected to the control unit 11. As described above, the drain of the switching element Q4 is connected to the gate of the switching element Q3. The source of the switching element Q4 is grounded. That is, a predetermined gate voltage is applied to the gate of the switching element Q4 by the control unit 11, so that the switching element Q4 is turned on. In addition, by turning on the switching element Q4, the gate voltage is applied to the gate of the switching element Q3. As a result, the switching element Q3 is turned on.

[0027] The voltage measuring unit 13 is configured to be connected in parallel with the above-mentioned rechargeable battery BA to measure the battery voltage of the above-mentioned rechargeable battery BA. The battery remaining meter 14 is configured to estimate the battery remaining amount of the above-mentioned rechargeable battery BA based on the battery voltage of the above-mentioned rechargeable battery BA measured by the above-mentioned voltage measuring unit 13. For example, the battery remaining meter 14 in this embodiment estimates the battery remaining amount when the control unit 11 instructs to start supplying power to the driving power source Vcc based on the battery voltage detected at the timing when the control unit 11 instructs to start supplying power to the driving power source Vcc. In addition, the battery remaining meter 14 is configured to display the above-mentioned battery remaining amount. For example, the battery remaining meter 14 displays the above-mentioned battery remaining amount on a display device (not shown) such as a display built into the battery remaining meter 14 itself or an external display.

[0028] Here, in the power supply device 1 involved in the present embodiment, the diode D is provided on the electrical path L5 between the source of the switching element Q1 and the connection part of the electrical path L4 connected to the drain of the switching element Q3, the electrical path L6 between the source of the switching element Q2 and the connection part of the electrical path L3 connected to the source of the switching element Q2, the electrical path L7 between the voltage converter CV and the connection part of the electrical path L3 connected to the source of the switching element Q2, and the electrical path L8 between the switching element Q1 and the switching element Q3, so as to prevent the current in each path from flowing in the reverse direction.

[0029] (Relationship between the battery voltage of the rechargeable battery and the on-off state of each switching element)

[0030] Next, refer to Figure 2 The relationship between the battery voltage of the rechargeable battery BA and the on-off state of each switching element will be described in detail. Figure 2 is Figure 1 An example of a timing chart when the power supply device 1 shown in FIG. 1 is used to discharge the rechargeable battery BA and then to charge the rechargeable battery BA. Figure 1 The power supply device 1 shown is based on Figure 2 In the timing chart shown in FIG. 1 , the fully charged rechargeable battery BA is discharged, the operation is stopped after the discharge of the rechargeable battery BA is performed, and the rechargeable battery BA is charged after restarting. Figure 2 In the timing chart shown, the vertical axis represents the battery voltage value of the rechargeable battery BA or the battery remaining value estimated by the battery remaining meter 14 and the state of each switch element, and the horizontal axis represents time. Figure 2 At the start of the timing chart shown (ie, time T0), the power supply device 1 according to the present embodiment is started. That is, it is assumed that the switching element Q3 and the switching element Q4 are turned on by the control unit 11 at time T0.

[0031] First, if Figure 2As shown, the power supply device 1 according to the present embodiment is in the period from the time T0 to the time T when the discharge of the rechargeable battery BA starts. sd During the previous period, neither charging nor discharging of the rechargeable battery BA was performed. At this time, the battery voltage value of the rechargeable battery BA and the remaining battery level estimated by the battery level meter 14 are constant.

[0032] In addition, control unit 11 of control unit CU turns off switching element Q1 and switching element Q2. In addition, as described above, control unit 11 maintains the on state of switching element Q3 and switching element Q4.

[0033] Then, if Figure 2 As shown, the power supply device 1 according to the present embodiment is sd Time T until discharge of rechargeable battery BA is completed ed The discharge of the rechargeable battery BA is started during the period up to the period, and the discharge of the rechargeable battery BA is terminated after the discharge of the rechargeable battery BA is performed only during the period. At this time, due to the discharge characteristics of the rechargeable battery BA, the battery voltage value of the rechargeable battery BA drops rapidly when the discharge of the rechargeable battery BA is performed, and slowly drops in the middle stage of the period, and drops rapidly again when the discharge of the rechargeable battery BA is completed. In addition, the battery remaining value estimated by the battery remaining meter 14 decreases linearly.

[0034] In addition, the control unit 11 performs the above-mentioned time T sd The control unit 11 turns on the switching element Q2, maintains the off state of the switching element Q1, and maintains the on state of the switching element Q3 and the switching element Q4. sd After that, at time T ed During the period before, the switch element Q1 is maintained in the off state, and the switch elements Q2, Q3, and Q4 are maintained in the on state. ed , turn off the switching element Q2, maintain the off state of the switching element Q1, and maintain the on state of the switching element Q3 and the switching element Q4.

[0035] Then, if Figure 2 As shown, the power supply device 1 according to the present embodiment stops supplying the driving power supply Vcc from the time Ted to the time Tc when the control unit 11 instructs to stop supplying the driving power supply Vcc. offDuring the period from 0 to 100 ms (i.e., the time when the power supply device 1 is stopped), the charging battery BA is not discharged, the power supply to the charging and discharging circuit FC is maintained, and after the power supply to the charging and discharging circuit FC is maintained, the power supply to the charging and discharging circuit FC is stopped, and the control unit 11 instructs to stop the power supply to the driving power supply Vcc. At this time, the battery voltage value of the charging battery BA gradually increases and becomes constant at the last stage of this period. In addition, the battery remaining value estimated by the battery remaining meter 14 is constant.

[0036] Here, as a reason why the remaining battery level value estimated by the battery remaining level meter 14 is constant, the method of estimating the battery voltage performed by the battery remaining level meter 14 is listed. The battery remaining level meter 14 is configured to estimate the remaining battery level of the rechargeable battery BA based on the battery voltage of the rechargeable battery BA. That is, if the rechargeable battery BA is not charged or discharged, the remaining battery level will not increase or decrease. Therefore, the remaining battery level value estimated by the battery remaining level meter 14 is constant.

[0037] In addition, the control unit 11 performs the above-mentioned time T ed After that, at time T off During the period before, the switch elements Q1 and Q2 are kept in the off state, and the switch elements Q3 and Q4 are kept in the on state. off , maintain the off state of the switch element Q1 and the switch element Q2, and turn off the switch element Q3 and the switch element Q4. That is, the control unit 11 of the present embodiment instructs to stop supplying power to the driving power source Vcc at the timing when the battery voltage measured by the voltage measuring unit 13 becomes stable (that is, becomes constant) after the discharge of the rechargeable battery BA by the charge-discharge circuit FC is completed. In the power supply device 1 involved in the present embodiment, the timing when the battery voltage of the rechargeable battery BA becomes stable is the timing when the rate of change per unit time of the battery voltage becomes less than a predetermined threshold value.

[0038] Then, if Figure 2 As shown in FIG. 1 , the power supply device 1 according to the present embodiment is, for example, off Then, the time T from when the control unit 11 instructs the start of supplying power to the driving power source Vcc is reached. on During the period from the start of the power supply device 1 to the start of the power supply device 1, the operation is stopped by the control unit 11 instructing to stop the supply of the driving power supply Vcc, and after the operation is stopped, the operation is started by the control unit 11 instructing to start the supply of the driving power supply Vcc, and the control unit CU starts to supply power to the charging and discharging circuit FC. At this time, the battery voltage value of the rechargeable battery BA and the battery remaining amount estimated by the battery remaining amount meter 14 remain constant.

[0039] In addition, the control unit 11 performs the above-mentioned time T offAfter that, at time T on In the period before, the switch element Q1, the switch element Q2, the switch element Q3 and the switch element Q4 are maintained in the off state. on , maintaining the off state of the switching element Q1 and the switching element Q2, and turning on the switching element Q3 and the switching element Q4.

[0040] Then, if Figure 2 As shown, the power supply device 1 according to the present embodiment is, for example, on Then, the time T for charging the rechargeable battery BA is reached. sc During the period, the control unit CU supplies power to the charge-discharge circuit FC, and after the control unit CU supplies power to the charge-discharge circuit FC, the rechargeable battery BA is charged. At this time, the battery voltage value of the rechargeable battery BA and the battery remaining amount estimated by the battery remaining amount meter 14 remain constant.

[0041] In addition, the control unit 11 performs the above-mentioned time T on After that, at time T sc During the period before, the switch elements Q1 and Q2 are kept in the off state, and the switch elements Q3 and Q4 are kept in the on state. sc , turning on the switching element Q1, maintaining the switching element Q2 in the off state, and maintaining the switching element Q3 and the switching element Q4 in the on state.

[0042] Finally, if Figure 2 As shown, the power supply device 1 according to this embodiment is sc After that, the charging of the rechargeable battery BA is continued. At this time, the battery voltage value of the rechargeable battery BA rises rapidly immediately after the charging of the rechargeable battery BA is executed, and then rises slowly. In addition, the battery remaining value estimated by the battery remaining meter 14 rises linearly.

[0043] In addition, the control unit 11 performs the above-mentioned time T sc Thereafter, the switching element Q1 , the switching element Q3 , and the switching element Q4 are maintained in the on state, and the switching element Q2 is maintained in the off state.

[0044] (Summarize)

[0045] As described above, in the power supply device 1 according to the present embodiment, the control unit 11 of the control unit CU stops the supply of power to the charge-discharge circuit FC at the timing when the battery voltage measured by the voltage measuring unit 13 stabilizes after the discharge of the rechargeable battery BA by the charge-discharge circuit FC is completed. In addition, the battery remaining amount meter 14 of the control unit CU estimates the battery remaining amount when the control unit 11 instructs the start of supply of power to the drive power source Vcc, based on the battery voltage detected at the timing when the control unit 11 instructs the start of supply of power to the drive power source Vcc.

[0046] For example, Figure 3 As shown in FIG. 1 , after the discharge of the rechargeable battery BA is stopped, at the timing when the battery voltage of the rechargeable battery BA is unstable (i.e., the rate of change per unit time of the battery voltage is large), an instruction is given to stop supplying power to the driving power source Vcc. In this case, due to the influence of the battery voltage fluctuation, the battery voltage continues to fluctuate even after the discharge of the rechargeable battery is stopped. Therefore, although it is necessary to Figure 3 The estimated battery level will be as follows: Figure 3 If the value becomes lower than the thin line in the figure, the remaining battery value will be incorrect.

[0047] On the other hand, in the power supply device 1 according to the present embodiment, the control unit 11 of the control unit CU instructs to stop supplying power to the driving power supply Vcc when the battery voltage measured by the voltage measuring unit 13 is stable, taking into account the fluctuation of the battery voltage. Thus, the power supply device 1 according to the present embodiment estimates the remaining battery capacity in consideration of the above-mentioned error, and can therefore accurately estimate the remaining battery capacity of the rechargeable battery BA. That is, the power supply device 1 according to the present embodiment can improve the accuracy of estimating the remaining battery capacity.

[0048] In addition, if Figure 1 As shown in FIG. 1 , the control unit CU in this embodiment is built into the battery pack BP. However, the control unit CU in this embodiment is not limited thereto. Figure 4 As shown, the control unit CU in this embodiment can be assembled as one structure of the power supply device 1.

[0049] In addition, in the power supply device 1 in the present embodiment, the timing of the battery voltage stabilization of the rechargeable battery BA is the timing when the rate of change of the battery voltage per unit time becomes less than a specified threshold value. However, the power supply device 1 involved in the present embodiment is not limited to this. For example, in the power supply device 1 in the present embodiment, the timing of the battery voltage stabilization can be set to the timing after a preset time has passed after the end of discharge. In this case, the set time is set to 30 minutes to 2 hours. In addition, the timing of the battery voltage stabilization can be set to the timing when the battery voltage has only changed by a specified value relative to the battery voltage at the end of discharge.

[0050] In addition, it can be seen from the shared path that in this embodiment, the power that can be supplied to the load 2 and the power that can be supplied to the rechargeable battery BA are the same. However, the power supply device 1 involved in this embodiment is not limited to this. In this embodiment, an inverter can also be provided in the power supply device 1, and the power stored in the rechargeable battery BA can be output after being converted into a desired voltage.

[0051] In addition, the external power supply PS in this embodiment can be either a household power supply or a commercial power supply. In addition, the external power supply PS can be either a power supply that can provide direct current or a power supply that can provide alternating current. That is, the power supply device 1 involved in this embodiment can appropriately change the internal structure according to the type of the external power supply PS and the power that can be used in the load 2. At this time, the voltage converter CV in this embodiment can be appropriately changed according to the type of the external power supply PS and the power used in the load 2. For example, the voltage converter CV in this embodiment can be either a rectifier (AC-DC converter) or a DC-DC converter.

[0052] In addition, the rechargeable battery BA in this embodiment is a generally known battery such as a lithium ion battery or a lead-acid battery. In addition, the load 2 in this embodiment is assumed to be, for example, a personal computer, a server, a storage device, and other devices that are required to operate for a certain period of time when the power supply from the external power supply PS stops.

[0053] In addition, the term "prescribed processor" used in the above description means, for example, a dedicated or general-purpose processor such as a CPU (Central Processing Unit), an MPU (Micro Processing Unit), or a GPU (Graphics Processing Unit), or an application-specific integrated circuit (ASIC: Application Specific Integrated Circuit), a programmable logic device (for example, a simple programmable logic device (SPLD: Simple Programmable Logic Device), a complex programmable logic device (CPLD: Complex Programmable Logic Device), and a field programmable gate array (FPGA: Field Programmable Gate Array), etc. In addition, the various structural elements of the present embodiment are not limited to a single processor, and can also be implemented using multiple processors. In addition, multiple structural elements can also be implemented using a single processor.

Claims

1. A control unit (CU) for controlling the operation of a charge-discharge circuit (FC) for charging or discharging a rechargeable battery (BA), characterized in that: include: a control unit (11) configured to control power supply for operating the charge and discharge circuit (FC); a driving power source (Vcc) for providing driving power to the control unit (11); a voltage measuring unit (13) configured to measure a battery voltage of the rechargeable battery (BA); and a battery remaining amount meter (14) configured to estimate the battery remaining amount of the rechargeable battery (BA) based on the battery voltage of the rechargeable battery (BA) measured by the voltage measuring unit (13); The battery remaining meter (14) estimates the battery remaining when the control unit (11) instructs to start supplying power to the driving power source (Vcc), based on the battery voltage detected at the timing when the control unit (11) instructs to start supplying power to the driving power source (Vcc). The control unit (11) instructs the stopping of the supply of power to the driving power source (Vcc) at the timing when the battery voltage measured by the voltage measuring unit (13) becomes stable after the discharge of the rechargeable battery (BA) by the charge and discharge circuit (FC) is completed.

2. The control unit (CU) according to claim 1, characterized in that The timing at which the battery voltage stabilizes is the timing at which the rate of change per unit time of the battery voltage becomes smaller than a predetermined threshold value.

3. The control unit (CU) according to claim 1, characterized in that The timing at which the battery voltage stabilizes is the timing after a predetermined time has passed after the discharge is completed.

4. The control unit (CU) according to claim 3, characterized in that The time is 30 minutes to 2 hours.

5. The control unit (CU) according to claim 1, characterized in that The timing at which the battery voltage stabilizes is the timing at which the battery voltage changes by a predetermined value relative to the battery voltage at the end of discharge.

6. A battery pack (BP), comprising a control unit (CU) for controlling the operation of a charge-discharge circuit (FC) for charging or discharging a rechargeable battery (BA), the charge-discharge circuit (FC), and the rechargeable battery (BA), wherein the battery pack (BP) is characterized in that: The control unit (CU) comprises: a control unit (11) configured to control power supply for operating the charge and discharge circuit (FC); a driving power source (Vcc) for providing driving power to the control unit (11); a voltage measuring unit (13) configured to measure a battery voltage of the rechargeable battery (BA); and a battery remaining amount meter (14) configured to estimate the battery remaining amount of the rechargeable battery (BA) based on the battery voltage of the rechargeable battery (BA) measured by the voltage measuring unit (13); The battery remaining meter (14) estimates the battery remaining when the control unit (11) instructs to start supplying power to the driving power source (Vcc), based on the battery voltage detected at the timing when the control unit (11) instructs to start supplying power to the driving power source (Vcc). The control unit (11) instructs the stopping of the supply of power to the driving power source (Vcc) at the timing when the battery voltage measured by the voltage measuring unit (13) becomes stable after the discharge of the rechargeable battery (BA) by the charge and discharge circuit (FC) is completed.

7. A power supply device (1), comprising: A control unit (CU) for controlling the operation of a charge-discharge circuit (FC) for charging or discharging a rechargeable battery (BA); the charge-discharge circuit (FC); and the rechargeable battery (BA), wherein the power supply device (1) is characterized in that: The control unit (CU) comprises: a control unit (11) configured to control power supply for operating the charge and discharge circuit (FC); a driving power source (Vcc) for providing driving power to the control unit (11); a voltage measuring unit (13) configured to measure a battery voltage of the rechargeable battery (BA); and a battery remaining amount meter (14) configured to estimate the battery remaining amount of the rechargeable battery (BA) based on the battery voltage of the rechargeable battery (BA) measured by the voltage measuring unit (13); The battery remaining meter (14) estimates the battery remaining when the control unit (11) instructs to start supplying power to the driving power source (Vcc), based on the battery voltage detected at the timing when the control unit (11) instructs to start supplying power to the driving power source (Vcc). The control unit (11) instructs the stopping of the supply of power to the driving power source (Vcc) at the timing when the battery voltage measured by the voltage measuring unit (13) becomes stable after the discharge of the rechargeable battery (BA) by the charge and discharge circuit (FC) is completed.

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