Charger

Abstract

To improve reliability of a charger.SOLUTION: A charger of one embodiment of the present disclosure comprises: a power source; a power conversion unit; a power source voltage measurement unit; a control unit; and a battery pack information acquisition unit. The power conversion unit converts source power output from the power source into charge power for charging a battery pack. The battery pack information acquisition unit acquires upper limit value specification information which can specify a charge current upper limit value from the battery pack. The control unit calculates a value of the charge current output by the charger as a voltage maintenance charge current value so that a power source output voltage value is included within a power source output voltage range on the basis of the power source output voltage value measured by the power source voltage measurement unit. The control unit uses a smaller value of the voltage maintenance charge current value and the charge current upper limit value as a charge current determination value and controls the power conversion unit to output the charge current having the charge current determination value.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a charger for charging a battery. [Background technology]

[0002] Patent Document 1 describes a charger that charges a battery pack using a solar cell as a power source, in which a charging current value is controlled so as to maintain the voltage of the solar cell at a constant value. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-55588 A Summary of the Invention [Problem to be solved by the invention]

[0004] The charger described in Patent Document 1 is configured so that the charging current cannot be specified from the microcontroller installed in the charger, and there is a possibility that a charging current larger than the allowable current value of the battery being charged by the charger will flow.

[0005] One aspect of the present disclosure aims to improve the reliability of a charger. [Means for solving the problem]

[0006] A charger according to one aspect of the present disclosure is a charger for charging a battery pack, and includes a power source, a power conversion unit, a power source voltage measurement unit, a control unit, and a battery pack information acquisition unit. The power supply is connected to the charger. The power conversion unit is configured to receive power supply power output from the power supply and convert the power supply power into charging power for charging the battery pack. The power supply voltage measurement unit is configured to measure a power supply output voltage value that is a value of a power supply output voltage output by the power supply.

[0007] The control unit is configured to control the power conversion unit. The battery pack information acquisition unit is configured to acquire, from the battery pack, upper limit value identification information capable of identifying a charging current upper limit value that is an upper limit value of a charging current input from the charger to the battery pack.

[0008] The control unit is configured to calculate, based on the power supply output voltage value measured by the power supply voltage measuring unit, a voltage maintaining charging current value, which is a value of the charging current output by the charger so that the power supply output voltage value is within a preset power supply output voltage range.

[0009] The control unit is configured to set the smaller of the voltage maintaining charge current value and the charge current upper limit value as a charge current determination value, and to control the power conversion unit to output a charge current having the charge current determination value.

[0010] Such a charger can output a charging current so as not to exceed the charging current upper limit value specified based on the upper limit value specifying information acquired from the battery pack. Therefore, the charger can prevent a charging current exceeding a value that the battery pack can tolerate from flowing through the battery pack and damaging the battery pack, thereby improving the reliability of the charger.

[0011] A charger according to another aspect of the present disclosure is a charger for charging a battery pack, and includes a power source, a power conversion unit, a control unit, a charging current measurement unit, a charging current integration unit, and a transmission unit.

[0012] The charging current measuring unit is configured to measure the value of the charging current output by the charger. The charging current integrating unit is configured to calculate an integrated charging current value by integrating the values ​​of the charging current measured by the charging current measuring unit.

[0013] The transmission unit is configured to transmit the charging current integrated value calculated by the charging current integration unit to the battery pack. When the calculated integrated charging current value is equal to the integrated charging current value calculated last time, the charging current accumulation unit sets the sum of the previously calculated integrated charging current value and a preset dummy value as the currently calculated integrated charging current value.

[0014] Such a charger can prevent the battery pack from mistakenly determining that charging is complete when the total amount of charging current does not change due to a decrease in the output of the power source, thereby improving the reliability of the charger. [Brief description of the drawings]

[0015] [Figure 1] FIG. 2 is a block diagram showing the configuration of a charger. [Diagram 2] FIG. 2 is a block diagram showing a configuration of a battery pack. [Diagram 3] 6 is a flowchart showing a procedure of charging control executed by a charger MCU and a battery MCU. [Figure 4] 4 is a flowchart showing a procedure for calculating a charging current value. [Diagram 5] 1 is a graph showing DC power characteristics of a solar cell. [Figure 6] FIG. 4 is a block diagram showing a power supply path to a control circuit. [Figure 7] 4 is a graph showing changes over time in a solar cell voltage value and a backup voltage value. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] [Summary of the embodiment] An embodiment may provide a charger for charging a battery pack, the charger having at least one of the following features 1 to 7. Feature 1: The power source that is connected to the charger. Feature 2: A power conversion unit configured to receive power supply power output from a power supply and convert the power supply power into charging power for charging the battery pack. Feature 3: A power supply voltage measuring unit configured to measure a power supply output voltage value, which is a value of a power supply output voltage output by a power supply. Feature 4: A control unit configured to control the power conversion unit. Feature 5: A battery pack information acquisition unit configured to acquire, from the battery pack, upper limit value identification information capable of identifying a charging current upper limit value that is an upper limit value of a charging current input from the charger to the battery pack. Feature 6: The control unit is configured to calculate, based on the power supply output voltage value measured by the power supply voltage measuring unit, a value of a charging current output by the charger so that the power supply output voltage value is within a preset power supply output voltage range, as a voltage maintenance charging current value. Feature 7: The control unit is configured to set the smaller of the voltage maintaining charging current value and the charging current upper limit value as the charging current determination value, and to control the power conversion unit to output a charging current having the charging current determination value.

[0017] A charger having at least features 1 to 7 can output a charging current so as not to exceed the charging current upper limit value specified based on the upper limit value specifying information acquired from the battery pack. Therefore, such a charger can prevent the occurrence of a situation in which a charging current exceeding an allowable value flows into the battery pack and the battery pack is damaged, and can improve the reliability of the charger.

[0018] An embodiment may include the following feature 8 in addition to or instead of at least one of the features 1 to 7 described above. Feature 8: The control unit is further configured to set the charging current determination value to the smallest value among a maximum charging current value, which is the maximum charging current value that the charger can output, a voltage maintaining charging current value, and a charging current upper limit value.

[0019] A charger having at least features 1 to 8 can prevent the power conversion unit from being damaged when the power conversion unit is controlled to output a charging current exceeding the maximum charging current value, thereby improving the reliability of the charger.

[0020] An embodiment may include the following feature 9 in addition to or instead of at least one of the features 1 to 8 described above. Feature 9: The control unit is further configured to set the charging current determination value to 0 [A] when the calculated charging current determination value is smaller than a minimum charging current value that is the minimum charging current that the charger can output.

[0021] A charger having at least features 1 to 7 and 9 controls the power conversion unit to output a charging current smaller than the minimum charging current value, thereby preventing the occurrence of situations in which an unstable current is supplied, and improving the reliability of the charger.

[0022] An embodiment may include at least one of the following features 10 to 11 in addition to or instead of at least one of the features 1 to 9 described above. Feature 10: A charging current measuring unit configured to measure a value of a charging current output by the charger. Feature 11: A charging current integrating unit configured to calculate an integrated charging current value by integrating the values ​​of the charging current measured by the charging current measuring unit.

[0023] A charger having at least the features 1 to 7 and 10 to 11 can grasp the total amount of charging current supplied to the battery pack. An embodiment may include the following feature 12 in addition to or instead of at least one of the features 1 to 11 described above. Feature 12: A transmitting unit configured to transmit the charging current integrated value calculated by the charging current integrating unit to the battery pack.

[0024] A charger having at least the features 1 to 7 and 10 to 12 can provide the battery pack with information indicating the total amount of charging current supplied to the battery pack. An embodiment may include the following feature 13 in addition to or instead of at least one of the features 1 to 12 described above. Feature 13: When the calculated integrated charging current value is equal to the previously calculated integrated charging current value, the charging current integration unit adds a preset dummy value to the previously calculated integrated charging current value, and sets the resulting sum as the currently calculated integrated charging current value.

[0025] A charger having at least features 1 to 7 and 10 to 13 can prevent the battery pack from mistakenly determining that charging is complete when the total amount of charging current does not change due to a decrease in the power supply output, thereby improving the reliability of the charger.

[0026] An embodiment may include the following feature 14 in addition to or instead of at least one of the features 1 to 13 described above. Feature 14: The dummy value is a value corresponding to the smallest unit of charge capacity used in the battery pack.

[0027] An embodiment may include the following feature 15 in addition to or instead of at least one of the features 1 to 14 described above. Feature 15: A power storage unit configured to store in advance the power required for the control unit to operate.

[0028] A charger having at least features 1 to 7 and 15 can prevent the control unit from stopping operation even when the power source is no longer able to supply power to the control unit due to a drop in the power source's output.

[0029] An embodiment may include the following feature 16 in addition to or instead of at least one of the features 1 to 15 described above. Feature 16: A power storage power acquisition unit configured to charge the power storage unit using power supply power output from a power source.

[0030] A charger having at least the features 1 to 7 and 15 to 16 can store electric charge in advance in the power storage unit using electric power from the power source when the output of the power source is not reduced. An embodiment may include at least one of the following features 17 to 18 in addition to or instead of at least one of the features 1 to 16 described above. Feature 17: The storage power acquisition unit is connected so as to be able to receive power from the power source. Feature 18: A reverse current blocking circuit for blocking power supply from the battery pack to the storage power source acquiring unit is provided on the current path between the storage power source acquiring unit and the battery pack.

[0031] A charger having at least the features 1 to 7 and 15 to 18 can prevent the occurrence of a situation in which electric charge is stored in the power storage unit using power from the battery pack, and can prevent a voltage drop in the battery pack.

[0032] An embodiment may include the following feature 19 in addition to or instead of at least one of the features 1 to 18 described above. Feature 19: The storage power acquisition unit includes a bidirectional converter.

[0033] An embodiment may include the following feature 20 in addition to or instead of at least one of the features 1 to 19 described above. Feature 20: The storage power source acquisition unit is configured to drive the bidirectional converter to supply power from the power source to the storage unit when a preset storage determination condition indicating that the power source output voltage value is high is satisfied.

[0034] A charger having at least the features 1 to 7, 15 to 16, and 19 to 20 can store electric charge in advance in the power storage unit by using electric power from the power source when the output of the power source is not reduced.

[0035] An embodiment may include the following feature 21 in addition to or instead of at least one of the features 1 to 20 described above. Feature 21: The storage power acquisition unit is configured to stop driving the bidirectional converter when the voltage value of the storage unit reaches a preset first drive stop determination value after the bidirectional converter is driven.

[0036] A charger having at least the features 1 to 7, 15 to 16, and 19 to 21 can suppress the supply of excessive power to the power storage unit. An embodiment may include the following feature 22 in addition to or instead of at least one of the features 1 to 21 described above. Feature 22: The storage power acquisition unit is configured to drive the bidirectional converter to supply power from the storage unit to the control unit when a preset discharge determination condition indicating that the power supply output voltage value is low is satisfied.

[0037] A charger having at least the features 1 to 7, 15 to 16, 19, and 22 can suppress the occurrence of a situation in which the operation of the control unit stops when the output of the power source drops. An embodiment may include the following feature 23 in addition to or instead of at least one of the features 1 to 22 described above. Feature 23: The storage power acquisition unit is configured to stop driving the bidirectional converter when the voltage of the storage unit falls below a preset second drive stop determination value after the bidirectional converter is driven.

[0038] A charger having at least the features 1 to 7, 15 to 16, 19, and 22 to 23 can prevent an unstable control voltage from being supplied from the power storage unit to the control unit even when the charge stored in the power storage unit is small.

[0039] An embodiment may include at least one of the following features 24-25 in addition to or instead of at least one of the features 1-23 described above. Feature 24: The bidirectional converter includes a step-down converter. Feature 25: The bidirectional converter drives the step-down converter to supply power from the power supply to the power storage unit.

[0040] An embodiment may include at least one of the following features 26-27 in addition to or instead of at least one of the features 1-25 described above. Feature 26: The bidirectional converter includes a step-up converter. Feature 27: The bidirectional converter drives the step-up converter to supply power from the power storage unit to the control unit.

[0041] In some embodiments, features 1-27 may be combined in any combination. In some embodiments, any of features 1-27 may be omitted. Specific Exemplary Embodiments Exemplary embodiments of the present disclosure will now be described with reference to the drawings.

[0042] As shown in Fig. 1, the charger 1 of this embodiment includes a solar cell 2, a charger MCU 3, a DC / DC converter 4, a first detection circuit 5, and a first communication circuit 6. MCU is an abbreviation for Micro Control Unit. The charger 1 is a device for charging a battery pack 100 shown in Fig. 2. The battery pack 100 is attached to an electric work machine and supplies power to the attached electric work machine.

[0043] The solar cell 2 converts solar energy into DC power and outputs it. The charger MCU3 includes a microcomputer having a CPU3a, a ROM3b, and a RAM3c. Various functions of the microcomputer are realized by the CPU3a executing a program stored in a non-transitory real-world recording medium. In this example, the ROM3b corresponds to the non-transitory real-world recording medium storing the program. Furthermore, the execution of this program executes a method corresponding to the program. Note that some or all of the functions executed by the CPU3a may be achieved by one or more electronic components such as ICs. The charger MCU3 may include one or more microcomputers.

[0044] The DC / DC converter 4 generates DC power (hereinafter, charging power) by converting the DC power supplied from the solar cell 2 according to an instruction from the charger MCU 3, and outputs the generated charging power. Specifically, the DC / DC converter 4 may step up or step down the DC power supplied from the solar cell 2 depending on the magnitude of the voltage output by the solar cell 2.

[0045] The first detection circuit 5 detects whether the battery pack 100 is connected to the charger 1 or not, and outputs a connection signal or a non-connection signal to the charger MCU 3. The first communication circuit 6 is a circuit for allowing the charger MCU 3 to execute serial communication with the battery pack 100.

[0046] The charger 1 further includes a first positive terminal 11 , a first negative terminal 12 , a first charging terminal 13 , a first power supply terminal 14 , a first detection terminal 15 , and a first communication terminal 16 . The first positive terminal 11 is connected to a first positive line 8 through which the DC / DC converter 4 outputs charging power. The first negative terminal 12 is connected to a first negative line 9 through which the DC / DC converter 4 outputs charging power.

[0047] The first charging terminal 13 is a terminal for inputting a charging stop signal from the battery pack 100. The first power supply terminal 14 is a terminal for outputting the voltage of the auxiliary power supply to the battery pack 100.

[0048] The first detection terminal 15 is connected to the first detection circuit 5. The first communication terminal 16 is connected to the first communication circuit 6. The charger 1 further includes a first voltage dividing circuit 21, a second voltage dividing circuit 22, a first differential amplifier 23, a shunt resistor 24, an amplifier 25, and a second differential amplifier 26.

[0049] The first voltage dividing circuit 21 divides the DC voltage output from the solar cell 2 to produce a first divided voltage, and outputs the first divided voltage to the charger MCU 3. The second voltage dividing circuit 22 divides the voltage of the first positive line 8 to output a second divided voltage to the first differential amplifier 23.

[0050] The first differential amplifier 23 compares the second divided voltage with the voltage of the charging voltage setting signal, and outputs a first difference signal according to the difference between the second divided voltage and the voltage of the charging voltage setting signal to the DC / DC converter 4. The charging voltage setting signal is a signal that indicates the value of the charging voltage output by the DC / DC converter 4. The charging voltage setting signal is output from the charger MCU 3.

[0051] The shunt resistor 24 is installed on the first negative electrode line 9. The shunt resistor 24 outputs a shunt output voltage according to the magnitude of the current flowing through the shunt resistor 24. The value of the current flowing through the shunt resistor 24 corresponds to the value of the charging current output by the DC / DC converter 4.

[0052] The amplifier 25 amplifies the shunt output voltage output from the shunt resistor 24 and outputs the amplified signal to the second differential amplifier 26. The second differential amplifier 26 outputs a second differential signal corresponding to the difference between the voltage of the charging current command signal output from the charger MCU 3 and the voltage of the amplified signal output from the amplifier 25 to the DC / DC converter 4. The charging current command signal is a signal that commands the value of the charging current output by the DC / DC converter 4.

[0053] The DC / DC converter 4 is configured to output charging power having a charging voltage value and a charging current value instructed by the charger MCU 3 based on the first differential signal from the first differential amplifier 23 and the second differential signal from the second differential amplifier 26.

[0054] The charger 1 further includes a control power supply circuit 30, a regulator 31, a power-down detection circuit 32, a backup capacitor 33, a step-up / step-down converter , a first diode 35, and a second diode .

[0055] The control power supply circuit 30 converts the DC power supplied from the solar cell 2 to generate a control voltage, for example, 13.5V. The regulator 31 steps down the control voltage output from the control power supply circuit 30 to generate a 5V voltage for operating the charger MCU 3 and the like.

[0056] The power-down detection circuit 32 detects whether or not the value of the control voltage (hereinafter, referred to as the control voltage value) output by the control power supply circuit 30 is less than a preset power-down determination value. The backup capacitor 33 is a storage device that stores electric charge in preparation for when the control voltage value becomes small.

[0057] The step-up / step-down converter 34 steps down the 5V voltage generated by the regulator 31 and steps up the voltage of the backup capacitor 33 . The first diode 35 is disposed on the current path between the control power supply circuit 30 and the regulator 31. The anode of the first diode 35 is electrically connected to the control power supply circuit 30, and the cathode of the first diode 35 is electrically connected to the regulator 31.

[0058] The second diode 36 is installed on the first positive line 8. The anode of the second diode 36 is electrically connected to the DC / DC converter 4, and the cathode of the second diode 36 is electrically connected to the first positive terminal 11.

[0059] 2, the battery pack 100 includes a battery 101, a battery MCU 102, an AFE 103, a charge control circuit 104, a second detection circuit 105, and a second communication circuit 106. AFE is an abbreviation for Analog Front End.

[0060] The battery 101 is configured by connecting multiple chargeable and dischargeable secondary batteries in series. The battery 101 may be configured by connecting multiple secondary batteries in parallel, or may be configured by connecting multiple secondary batteries in series and parallel.

[0061] The battery MCU 102 includes a microcomputer having a CPU 102a, a ROM 102b, and a RAM 102c. Various functions of the microcomputer are realized by the CPU 102a executing a program stored in a non-transitory real recording medium. In this example, the ROM 102b corresponds to the non-transitory real recording medium storing the program. Furthermore, the execution of this program executes a method corresponding to the program. Note that some or all of the functions executed by the CPU 102a may be achieved by one or more electronic components such as ICs. The battery MCU 102 may include one or more microcomputers.

[0062] The AFE 103 is an analog circuit that detects the voltage and temperature of each secondary battery included in the battery 101 and executes cell balancing to equalize the remaining capacities of the multiple secondary batteries in accordance with commands from the battery MCU 102.

[0063] The charge control circuit 104 outputs a charge stop signal to the charger 1 when a charge stop signal is input from the AFE 103 or the battery MCU 102 . The second detection circuit 105 detects whether the charger 1 or the electric work machine is connected or disconnected to the battery pack 100, and outputs a connection signal or a disconnection signal to the battery MCU .

[0064] The second communication circuit 106 is a circuit for allowing the battery MCU 102 to execute serial communication with the charger 1. The battery pack 100 further includes a second positive terminal 111, a second negative terminal 112, a second charging terminal 113, a second power supply terminal 114, a second detection terminal 115, and a second communication terminal .

[0065] The second positive electrode terminal 111 is connected to the positive electrode of the battery 101. The second negative electrode terminal 112 is connected to the negative electrode of the battery 101. The second charging terminal 113 is connected to the charging control circuit 104. The second power supply terminal 114 is a terminal for inputting the voltage of the auxiliary power supply from the charger 1.

[0066] The second detection terminal 115 is connected to the second detection circuit 105. The second communication terminal is connected to the second communication circuit . When the battery pack 100 is attached to the charger 1, the second positive terminal 111, the second negative terminal 112, the second charging terminal 113, the second power supply terminal 114, the second detection terminal 115 and the second communication terminal 116 are connected to the first positive terminal 11, the first negative terminal 12, the first charging terminal 13, the first power supply terminal 14, the first detection terminal 15 and the first communication terminal 16, respectively.

[0067] The charger MCU 3 of the charger 1 and the battery MCU 102 of the battery pack 100 transmit and receive data by performing half-duplex UART communication with each other via the first communication terminal 16 and the second communication terminal 116. UART is an abbreviation for Universal Asynchronous Receiver / Transmitter.

[0068] Next, the charging control executed by the charger MCU 3 and the battery MCU 102 will be described. 3, when the battery pack 100 is attached to the charger 1, the charger MCU 3 and the battery MCU 102 execute initial communication indicated by arrow L1. In the initial communication, for example, the charger MCU 3 transmits specification information of the charger 1 to the battery MCU 102, and the battery MCU 102 transmits specification information of the battery pack 100 to the charger MCU 3.

[0069] When the initial communication is completed, the charger MCU 3 executes a self-check in S10. The self-check is, for example, a fault diagnosis of the charger 1. In S20, the charger MCU3 determines whether or not temperature standby is necessary. Specifically, the charger MCU3 performs standby mode communication with the battery MCU 102, as indicated by an arrow L2. Furthermore, as indicated by an arrow L3, the charger MCU3 receives battery temperature information indicating the temperature of the battery pack 100 from the battery MCU 102. Then, based on the battery temperature information, the charger MCU3 determines whether or not the temperature of the battery pack 100 is below a preset chargeable temperature indicating that the battery pack 100 can be charged. That is, the charger MCU3 determines that temperature standby is necessary when the temperature of the battery pack 100 is equal to or higher than the chargeable temperature. Note that the charger MCU3 repeatedly performs standby mode communication during temperature standby.

[0070] If temperature standby is required, the charger MCU 3 repeats the process of S20 to wait until temperature standby is no longer required. Then, when temperature standby is no longer required, the charger MCU 3 determines in S30 whether charging is completed.

[0071] Specifically, as indicated by an arrow L4, the charger MCU 3 performs charging mode communication with the battery MCU 102. In the charging mode communication, the charger MCU 3 transmits charging current integrated value information indicating a charging current integrated value described below to the battery MCU 102.

[0072] Furthermore, as indicated by arrow L5, the charger MCU3 receives from the battery MCU 102 charging completion information indicating whether charging has been completed or not, and requested current information indicating the charging current value requested for charging the battery pack 100 (hereinafter referred to as the battery requested current value).

[0073] Then, the charger MCU 3 determines whether or not charging is completed based on the charging completion information. If charging is complete, the charger MCU 3 stops driving the DC / DC converter 4 and ends charging control in S40. On the other hand, if charging is not complete, the charger MCU 3 measures the solar cell voltage value based on the first divided voltage input from the first voltage divider circuit 21 in S50.

[0074] The charger MCU 3 calculates the charging current value in S60. The procedure for calculating the charging current value in S60 will be described later. The charger MCU 3 drives the DC / DC converter 4 in S70.

[0075] The charger MCU 3 measures the charging current value based on the voltage of the amplified signal input from the amplifier 25 in S80. In S90, the charger MCU3 integrates the charging current value measured in S80.

[0076] In S100, the charger MCU3 determines whether the integrated charging current value calculated in S90 has increased. If the integrated charging current value has increased, the charger MCU3 proceeds to S30. On the other hand, if the integrated charging current value has not increased, the charger MCU3 adds a preset dummy value to the previously calculated integrated charging current value (hereinafter, previously calculated value) in S110, sets the resulting sum as the current integrated charging current value, and proceeds to S30. The dummy value is a value corresponding to the smallest unit of charging capacity used in the battery pack 100 (for example, 0.1 mAh in this embodiment).

[0077] The charger MCU 3 periodically executes the charging mode communication indicated by the arrow L4 until the charging is completed. In this charging mode communication, the charger MCU 3 transmits the latest charging current integrated value to the battery MCU 102.

[0078] Furthermore, when the above-mentioned initial communication ends, the battery MCU 102 determines whether or not temperature standby is necessary in S210. Specifically, the battery MCU 102 determines whether or not the temperature of the battery pack 100 is within a preset chargeable temperature range indicating that the battery pack 100 can be charged. That is, the battery MCU 102 determines that temperature standby is necessary when the temperature of the battery pack 100 is outside the chargeable temperature range. When it is determined that temperature standby is necessary, the battery MCU 102 transmits battery temperature information indicating the temperature of the battery pack 100 as a value equal to or higher than the above-mentioned chargeable temperature to the charger MCU 3.

[0079] If temperature standby is necessary, the battery MCU 102 waits until temperature standby is no longer necessary by repeating the process of S210. Then, when temperature standby is no longer necessary, the battery MCU 102 transmits battery temperature information indicating the temperature of the battery pack 100 as a value below the above-mentioned chargeable temperature to the charger MCU 3. After that, the battery MCU 102 calculates the above-mentioned battery required current value in S220.

[0080] In S230, the battery MCU 102 determines whether charging of the battery pack 100 is completed. When the process of S230 ends, the battery MCU 102 transmits the above-mentioned charge completion information and the above-mentioned requested current information to the charger MCU 3, as indicated by an arrow L5.

[0081] Then, in S240, the battery MCU 102 determines whether or not charging of the battery pack 100 is completed based on the determination result of S230. If charging is not completed, the battery MCU 102 proceeds to S220. On the other hand, if charging is completed, the battery MCU 102 ends the charging control.

[0082] Next, the procedure for calculating the charging current value executed in S60 will be described. 4, when the charge current value calculation is started, the charger MCU3 determines in S310 whether the charge current value calculation is the first time or not. If the charge current value calculation is the first time, the charger MCU3 sets the above battery request current value as the next output current value Inext in S320, and proceeds to S390.

[0083] On the other hand, if the charging current value calculation is not the first time, the charger MCU 3 determines in S330 whether the solar cell voltage value is less than a preset lower limit value V_TGT_L. Here, when the solar cell voltage value is less than the lower limit value V_TGT_L, the charger MCU 3 sets the subtracted value obtained by subtracting a preset downward change width ΔIdown from the current output current value Inow as the next output current value Inext in S340, and proceeds to S380. The current output current value Inow is the next output current value Inext calculated in the previous S60.

[0084] On the other hand, when the solar cell voltage value is equal to or higher than the lower limit value V_TGT_L, the charger MCU 3 determines in S350 whether or not the solar cell voltage value exceeds a preset upper limit value V_TGT_H.

[0085] Here, if the solar cell voltage value exceeds the upper limit value V_TGT_H, the charger MCU 3 sets the next output current value Inext to the sum obtained by adding a preset increase change width ΔIup to the current output current value Inow in S360, and proceeds to S380.

[0086] On the other hand, when the solar cell voltage value is equal to or lower than the upper limit value V_TGT_H, the charger MCU 3 sets the current output current value Inow to the next output current value Inext in S370, and proceeds to S380.

[0087] When the process proceeds to S380, the charger MCU 3 sets the next output current value Inext to the smaller one of the next output current value Inext set in S340, S360, and S370 and the battery request current value, and proceeds to S390.

[0088] In S390, the charger MCU 3 sets the next output current value Inext to the smaller one of the next output current value Inext and a preset charger maximum current value. In S400, the charger MCU3 judges whether the next output current value Inext is less than a preset minimum possible current value. If the next output current value Inext is equal to or greater than the minimum possible current value, the charger MCU3 ends the charging current value calculation. On the other hand, if the next output current value Inext is less than the minimum possible current value, the charger MCU3 sets the next output current value Inext to 0 [A] in S410 and ends the charging current value calculation.

[0089] FIG. 5 is a graph showing characteristics of the DC power output by solar cell 2. As shown in FIG. As shown by arrow L11, when the amount of solar radiation decreases, the current value decreases at the same solar cell voltage value.

[0090] As shown by arrow L12, the charger MCU3 calculates the charging current value so that the solar cell voltage value falls within the range from the lower limit V_TGT_L to the upper limit V_TGT_H even if the characteristics of the DC power of the solar cell 2 fluctuate due to fluctuations in the amount of solar radiation.

[0091] As shown in FIG. 6, the regulator 31 supplies a voltage of 5V to the charger MCU 3 via the system power line 40. The step-up / step-down converter 34 includes a step-down converter 41 and a step-up converter 42 .

[0092] The step-down converter 41 steps down the voltage of the system power line 40 and supplies the stepped-down voltage to the backup capacitor 33 . The step-up converter 42 boosts the voltage of the backup capacitor 33 (hereinafter, referred to as the backup voltage) and supplies the boosted voltage to the system power line 40.

[0093] The power-down detection circuit 32 outputs a down detection signal to the step-up / step-down converter 34 when the control voltage value transitions from a state in which it is equal to or greater than the power-down determination value to a state in which it is less than the power-down determination value.

[0094] The power-down detection circuit 32 outputs an up detection signal to the step-up / step-down converter 34 when the control voltage value transitions from a state in which it is less than the power-down determination value to a state in which it is equal to or greater than the power-down determination value.

[0095] When the up-detection signal is input from the power-down detection circuit 32, the step-up / down converter 34 drives the step-down converter 41. When the down detection signal is input from the power-down detection circuit 32, the step-up / step-down converter 34 drives the step-up converter 42.

[0096] Note that when the control voltage value transitions from a state where it is less than the power-down determination value to a state where it is equal to or greater than the power-down determination value, the output of the down detection signal may be stopped. In other words, instead of inputting the up detection signal, the step-down converter 41 may be driven when the output of the down detection signal is stopped.

[0097] 7, with the control voltage and backup voltage at 0V, the control voltage rises from 0V at time t0, and when the control voltage value reaches the IC operation start voltage value of the step-up / step-down converter 34, the step-up / step-down converter 34 goes into charging mode and the step-down converter 41 is driven. This charges the backup capacitor 33.

[0098] When the backup voltage value is less than 1V, the buck-boost converter 34 starts operating in the initial mode M1. Then, at time t1, when the backup voltage value becomes 1 V or more, the step-up / step-down converter 34 transitions from the initial mode M1 to the backup standby mode M2. When the backup voltage value reaches 2.7 V and the backup capacitor 33 is fully charged, the step-up / step-down converter 34 stops driving the step-down converter 41 and stops charging the backup capacitor 33.

[0099] When the control voltage value falls below the power-down determination value at time t2 during backup standby mode M2, step-up / step-down converter 34 enters the discharge mode, and step-up converter 42 is driven. As a result, step-up / step-down converter 34 boosts the voltage to maintain 5V using backup capacitor 33 as the power source, and outputs the boosted voltage. Note that when the backup voltage falls below 0.5V, step-up / step-down converter 34 stops the backup operation.

[0100] The step-up / step-down converter 34 operates in the backup mode M3 during the period from when the control voltage value becomes less than the power-down determination value at time t2 to when the control voltage value becomes equal to or greater than the power-down determination value at time t5.

[0101] During the period from when the control voltage becomes less than 5V at time t3 to when the control voltage becomes 5V or higher at time t4, the charger MCU3 operates using only the backup capacitor 33 as a power source.

[0102] When the control voltage value becomes equal to or greater than the power-down determination value at time t5, the backup voltage value is less than 1 V, so that the step-up / step-down converter 34 starts operating in the initial mode M1.

[0103] Then, at time t6, when the backup voltage value reaches 1 V or more, the buck-boost converter 34 transitions from the initial mode M1 to the backup standby mode M2. When the backup voltage value reaches 2.7 V at time t7 and the backup capacitor 33 is fully charged, the buck-boost converter 34 stops driving the step-down converter 41 and stops charging the backup capacitor 33.

[0104] If the backup voltage value falls below 0.5 V during backup mode M3, the step-up / step-down converter 34 stops the backup operation and the charger 1 shuts down. During initial mode M1, if the voltage of the system power line 40 falls below 5V before the backup voltage value reaches 1V, the buck-boost converter 34 does not enter backup mode M3 and the charger 1 shuts down.

[0105] Such a charger 1 can output a charging current so as not to exceed a battery requested current value determined based on requested current information acquired from the battery pack 100. Therefore, the charger 1 can prevent a charging current exceeding an allowable value from flowing through the battery pack 100, thereby preventing the battery pack 100 from being damaged, and can improve the reliability of the charger 1.

[0106] The charger 1 can prevent the occurrence of a situation in which the DC / DC converter 4 is damaged when the DC / DC converter 4 is controlled to output a charging current exceeding the charger maximum current value, thereby improving the reliability of the charger 1.

[0107] The charger 1 controls the DC / DC converter 4 to output a charging current smaller than the minimum outputtable current value, thereby preventing the occurrence of a situation in which an unstable charging current is supplied, thereby improving the reliability of the charger 1.

[0108] The charger 1 can grasp the total amount of charging current supplied to the battery pack 100. The charger 1 can provide the battery pack 100 with information indicative of the total amount of charging current being supplied to the battery pack 100 .

[0109] The charger 1 can prevent the battery pack 100 from mistakingly determining that charging is complete when the total amount of charging current does not change due to a drop in the output of the solar cell 2, and can improve the reliability of the charger 1. The battery MCU 102 of the battery pack 100 performs a predetermined calculation on the charging current integrated value from the start to the completion of charging, and calculates the full charge capacity learning value of the battery pack 100. Here, when the battery MCU 102 of the battery pack 100 detects that the charging current integrated value received from the charger MCU 3 has not increased for a certain period of time, it determines that charging is complete, and calculates the full charge capacity learning value from the charging current integrated value at that time. For this reason, when the supply of the charging current is temporarily stopped and then the charging is resumed, the operation is equivalent to recharging, and the battery MCU 102 cannot calculate an accurate full charge capacity learning value. On the other hand, when the charging current integrated value has not increased, the charger 1 adds a dummy value to the previously calculated charging current integrated value, and sets the added value as the current charging current integrated value. As a result, the charger 1 prevents the battery pack 100 from mistakenly determining that charging is complete when the charging current integrated value has not increased, and enables the battery pack 100 to accurately calculate the full charge capacity learning value.

[0110] Even if the solar cell 2 is unable to supply power to the charger MCU 3 due to a drop in output from the solar cell 2, the charger 1 can prevent the operation of the charger MCU 3 from stopping.

[0111] The charger 1 can store electric charge in advance in the backup capacitor 33 using the power from the solar cell 2 when the output of the solar cell 2 is not decreasing. The charger 1 can prevent the occurrence of a situation in which electric charge is stored in the backup capacitor 33 using the power from the battery pack 100, and can prevent the voltage drop of the battery pack 100.

[0112] The charger 1 can store electric charge in advance in the backup capacitor 33 using the power from the solar cell 2 when the output of the solar cell 2 is not decreasing. The charger 1 can suppress the supply of excessive power to the backup capacitor 33.

[0113] When the output of the solar cell 2 drops, the charger 1 can prevent the occurrence of a situation in which the operation of the charger MCU 3 stops. The charger 1 can suppress the supply of an unstable control voltage from the backup capacitor 33 to the charger MCU 3 even when the charge stored in the backup capacitor 33 is small.

[0114] In the embodiments described above, the solar cell 2 corresponds to an example of a power source in the summary of the above embodiments, the DC / DC converter 4 corresponds to an example of a power conversion unit in the summary of the above embodiments, and the first voltage divider circuit 21 corresponds to an example of a power supply voltage measurement unit in the summary of the above embodiments.

[0115] Moreover, the charger MCU 3 corresponds to an example of the control unit in the summary of the above-mentioned embodiments, and the first communication circuit 6 corresponds to an example of the battery pack information acquisition unit in the summary of the above-mentioned embodiments. In addition, the power output by the solar cell 2 corresponds to an example of the power source power in the summary of the above embodiments, the power output by the DC / DC converter 4 corresponds to an example of the charging power in the summary of the above embodiments, and the solar cell voltage value corresponds to an example of the power source output voltage value in the summary of the above embodiments.

[0116] Moreover, the battery required current value corresponds to an example of the charging current upper limit in the summary of the above embodiment, and the required current information corresponds to an example of the upper limit specifying information in the summary of the above embodiment. In addition, the range from the lower limit value V_TGT_L to the upper limit value V_TGT_H corresponds to an example of a power supply output voltage range in the summary of the above embodiments, the next output current value Inext set in S340, S350, and S370 corresponds to an example of a voltage maintaining charging current value in the summary of the above embodiments, and the next output current value Inext set in S380, S390, and S410 corresponds to an example of a charging current determination value in the summary of the above embodiments.

[0117] In addition, the charger maximum current value corresponds to an example of a maximum charging current value in the summary of the above embodiments, the outputtable minimum current value corresponds to an example of a minimum charging current value in the summary of the above embodiments, the processing of S80 corresponds to an example of a charging current measurement unit in the summary of the above embodiments, and the processing of S90 corresponds to an example of a charging current integration unit in the summary of the above embodiments.

[0118] In addition, the first communication circuit 6 corresponds to an example of a transmitting section in the summary of the above embodiments, the backup capacitor 33 corresponds to an example of a power storage section in the summary of the above embodiments, the regulator 31, the power down detection circuit 32 and the step-up / step-down converter 34 correspond to an example of a power storage power acquisition section in the summary of the above embodiments, and the second diode 36 corresponds to an example of a reverse current blocking circuit in the summary of the above embodiments.

[0119] In addition, the control voltage value being equal to or greater than the power down judgment value corresponds to an example of a charge storage judgment condition in the summary of the above embodiments, and the control voltage value being less than the power down judgment value corresponds to an example of a discharge judgment condition in the summary of the above embodiments.

[0120] In addition, the step-up / step-down converter 34 corresponds to an example of a bidirectional converter in the summary of the above embodiments, 2.7 V at which the backup capacitor 33 is fully charged corresponds to an example of the first drive stop determination value in the summary of the above embodiments, and 0.5 V corresponds to an example of the second drive stop determination value in the summary of the above embodiments.

[0121] Although one embodiment of the present disclosure has been described above, the present disclosure is not limited to the above embodiment and can be implemented in various modified forms. In the above embodiment, the power source is a solar cell, but the power source may be, for example, a cigarette lighter socket, a fuel cell, or an AC generator.

[0122] In the above embodiment, the DC / DC converter 4 converts the power into charging power for charging the battery pack 100. However, the power conversion unit that converts the power into charging power for charging the battery pack 100 is not limited to the DC / DC converter 4, and may be, for example, an AC / DC converter, an insulated type, or a non-insulated type depending on the power source.

[0123] In the above embodiment, the requested current information indicating the battery requested current value is acquired from the battery pack 100. However, instead of the battery requested current value itself, information capable of identifying the battery requested current value may be acquired. For example, the charger 1 may acquire information on the cell voltage of the battery pack 100 and calculate an allowable charging current value.

[0124] In the above embodiment, the dummy value is a value corresponding to the minimum unit of charge capacity used in the battery pack 100. However, the battery pack 100 may transmit information indicating the minimum unit of charge capacity to the charger 1.

[0125] In the above embodiments, multiple functions of one component may be realized by multiple components, or one function of one component may be realized by multiple components. Also, multiple functions of multiple components may be realized by one component, or one function realized by multiple components may be realized by one component. Also, part of the configuration of the above embodiments may be omitted. Also, at least part of the configuration of the above embodiments may be added to or substituted for the configuration of another of the above embodiments.

[0126] In addition to the charger 1 described above, the present disclosure can also be realized in various forms, such as a system including the charger 1 as a component, a program for causing a computer to function as the charger 1, a non-transient physical recording medium such as a semiconductor memory on which the program is recorded, and a charging control method. [Another technical idea disclosed in this specification] [Item 1] A charger for charging a battery pack, comprising: a power source connected to the charger; a power conversion unit configured to receive power supply power output from the power supply and convert the power supply power into charging power for charging the battery pack; A control unit configured to control the power conversion unit; A charging current measurement unit configured to measure a value of a charging current output by the charger; a charging current integrating unit configured to calculate an integrated charging current value by integrating the charging current value measured by the charging current measuring unit; a transmitting unit configured to transmit the charging current integrated value calculated by the charging current integrating unit to the battery pack; Equipped with When the calculated integrated charging current value is equal to the integrated charging current value calculated last time, the charging current integration unit adds a preset dummy value to the integrated charging current value calculated last time, and sets this added value as the integrated charging current value calculated this time.

[0127] [Item 2] The charger according to item 1, A charger, wherein the dummy value is a value corresponding to the minimum unit of charge capacity used in the battery pack.

[0128] [Item 3] The charger according to item 1 or 2, further comprising: a power supply voltage measuring unit configured to measure a power supply output voltage value that is a value of a power supply output voltage output by the power supply; a battery pack information acquisition unit configured to acquire, from the battery pack, upper limit value specification information capable of specifying a charging current upper limit value that is an upper limit value of a charging current input from the charger to the battery pack; The control unit is calculating a charging current value, which is output by the charger, as a voltage maintaining charging current value so that the power supply output voltage value is within a preset power supply output voltage range based on the power supply output voltage value measured by the power supply voltage measuring unit; a charging current determination value being the smaller of the voltage maintaining charging current value and the charging current upper limit value, and the charger is configured to control the power conversion unit to output the charging current having the charging current determination value.

[0129] [Item 4] Item 3. The charger according to item 3, The control unit further A charger configured to set the charging current determination value to the smallest value among a maximum charging current value, which is the maximum charging current value that the charger can output, the voltage maintaining charging current value, and the charging current upper limit value.

[0130] [Item 5] The charger according to item 3 or 4, The control unit further The charger is configured to set the charging current determination value to 0 [A] when the calculated charging current determination value is smaller than a minimum charging current value that is the smallest charging current value that the charger can output. [Explanation of symbols]

[0131] Reference Signs List 1... charger, 2... solar cell, 3... charger MCU, 4... DC / DC converter, 6... first communication circuit, 21... first voltage divider circuit, 100... battery pack

Claims

1. A charger for charging a battery pack, The power supply connected to the charger, A power conversion unit configured to receive power output from the aforementioned power source and convert the power output into charging power for charging the battery pack, A power supply voltage measuring unit configured to measure a power supply output voltage value, which is the value of the power supply output voltage output of the aforementioned power supply, A control unit configured to control the power conversion unit, The system includes a battery pack information acquisition unit configured to acquire upper limit identification information from the battery pack that can identify the upper limit of the charging current, which is the upper limit of the charging current input from the charger to the battery pack, The control unit, Based on the power supply voltage output value measured by the power supply voltage measuring unit, the value of the charging current output by the charger is calculated as the voltage maintenance charging current value so that the power supply voltage output value falls within a preset power supply voltage range. A charger configured to control the power conversion unit so as to output the charging current having the charging current having the smaller of the voltage-maintaining charging current value and the charging current upper limit value, with the smaller value being the charging current determination value.

2. A charger according to claim 1, The control unit further, A charger configured to determine the charging current by setting the smallest of the following three values ​​as the charging current determination value: the maximum charging current value which is the maximum charging current value that the charger can output, the voltage-maintaining charging current value, and the upper limit of the charging current.

3. A charger according to claim 1 or claim 2, The control unit further, A charger configured to set the calculated charging current determination value to 0 [A] if the calculated charging current determination value is smaller than the minimum charging current value, which is the minimum charging current value that the charger can output.

4. A charger according to claim 1 or claim 2, further, A charging current measuring unit configured to measure the value of the charging current output by the charger, A charging current integrator is configured to calculate a charging current integrated value by accumulating the charging current values ​​measured by the charging current measuring unit. A charger equipped with the following features.

5. The charger according to claim 4, further, A charger comprising a transmitting unit configured to transmit the integrated charging current value calculated by the charging current integrating unit to the battery pack.

6. A charger according to claim 5, The charging current integrating unit, if the calculated charging current integrating value is equal to the previously calculated charging current integrating value, adds a preset dummy value to the previously calculated charging current integrating value to obtain the current calculated charging current integrating value.

7. A charger according to claim 6, The dummy value is a charger that corresponds to the smallest unit of charging capacity used within the battery pack.

8. A charger according to claim 1 or claim 2, further, A charger comprising a power storage unit configured to pre-store the power necessary for the control unit to operate.

9. The charger according to claim 8, further, A charger comprising a power acquisition unit for energy storage configured to charge the energy storage unit using the power output from the power source.

10. A charger according to claim 9, The aforementioned power storage power acquisition unit is connected to the power source so as to be able to receive power from the power source, A charger in which a reverse current blocking circuit is installed on the power supply path between the power storage power acquisition unit and the battery pack to prevent power supply from the battery pack to the power storage power acquisition unit.

11. A charger according to claim 9, The aforementioned power acquisition unit for energy storage is a charger including a bidirectional converter.

12. A charger according to claim 11, The power acquisition unit for energy storage is configured to drive the bidirectional converter to supply power from the power supply to the energy storage unit when a preset energy storage determination condition indicating that the power supply output voltage value is high is met.

13. A charger according to claim 12, The power storage unit is configured to stop driving the bidirectional converter after the bidirectional converter has been driven, when the voltage value of the power storage unit reaches a preset first drive stop determination value.

14. A charger according to claim 11, The power storage unit is configured to drive the bidirectional converter to supply power from the power storage unit to the control unit when a preset discharge determination condition indicating that the power supply output voltage value is low is met.

15. A charger according to claim 14, The power acquisition unit for energy storage is configured to stop driving the bidirectional converter after the bidirectional converter has been driven, if the voltage of the energy storage unit falls below a preset second drive stop determination value.

16. A charger according to claim 11, The aforementioned bidirectional converter includes a step-down converter, The bidirectional converter is a charger that supplies power from the power source to the energy storage unit by driving the step-down converter.

17. A charger according to claim 11, The aforementioned bidirectional converter includes a step-up converter, The bidirectional converter is a charger that supplies power from the energy storage unit to the control unit by driving the step-up converter.

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