Charging control system and charging method

Abstract

A charging control system 100 comprises: a battery body 11 that can be charged and discharged; a power source 2 that generates power; a charging circuit 12 that electrically connects the power source 2 and the battery body 11 so that the power source 2 charges the battery body 11, and can limit the magnitude of a charging current from the power source 2 to the battery body 11; and a charging control device 19 that controls the charging circuit 12. Upon determining the satisfaction of a predetermined restriction condition, the charge control device 19 restricts the magnitude of the charging current by controlling the charging circuit 12, and, upon determining the satisfaction of a predetermined restriction release condition, releases the restriction of the magnitude of the charging current by controlling the charging circuit 12.

Description

Charging control system and charging method

[0001] The present disclosure relates to a charging control system and a charging method.

[0002] Patent Document 1 discloses a battery (hereinafter referred to as a battery pack) that can be removed from a vehicle.

[0003] JP 2015-89754 A

[0004] According to Patent Document 1, a battery pack removed from a vehicle body is charged by a charger placed outside the vehicle.

[0005] Battery packs are generally charged by a dedicated charger that is compatible with the battery pack, and if a dedicated charger is not used, a current exceeding the allowable current may flow through the battery pack, which may electrically damage the electrical components of the battery, such as the battery cell or electrical wires.

[0006] Therefore, an object of the present disclosure is to provide a charging control system and a charging method that can easily prevent damage to a battery pack and can easily charge using various power sources.

[0007] One aspect of the present disclosure provides a charging control system comprising: a rechargeable battery body; a power source that generates electric power; a charging circuit that electrically connects the power source and the battery body so that the power source charges the battery body, the charging circuit being capable of limiting the magnitude of the charging current flowing from the power source to the battery body; and a charging control device that controls the charging circuit, wherein the charging control device controls the charging circuit to limit the magnitude of the charging current when it determines that predetermined limiting conditions are met, and controls the charging circuit to release the limit on the magnitude of the charging current when it determines that predetermined limit release conditions are met.

[0008] According to the present disclosure, a charge control device of a charge control system controls a charging circuit to limit the magnitude of the charging current when it determines that predetermined limiting conditions are met. Limiting the magnitude of the charging current makes it easier to prevent damage to the battery and the charging circuit. Furthermore, the charge control device of the charge control system controls the charging circuit to remove the limit on the magnitude of the charging current when it determines that predetermined limit-removal conditions are met. By removing the limit on the magnitude of the charging current, the charging current can be increased compared to when the magnitude of the charging current is limited, making it easier to shorten the charging time of the battery. Furthermore, because the charge control device controls the magnitude of the charging current, the power source that charges the battery does not need to have a function to adjust the power supplied depending on the battery. Therefore, the charge control system increases the versatility of the power sources that can be applied, making it easier to charge using various power sources.

[0009] Therefore, the charge control system and charging method according to the present disclosure make it easy to prevent damage to the battery pack and to charge it using various power sources.

[0010] Fig. 1 is a circuit diagram showing a battery pack and a power source according to a first embodiment of the present disclosure. Fig. 2 is a block diagram showing a charging control device of Fig. 1. Fig. 3 is a flowchart showing a charging method using the charging control device of Fig. 2. Fig. 4 is a circuit diagram showing a battery pack and a power source according to a second embodiment of the present disclosure. Fig. 5 is a circuit diagram showing a battery pack and a power source according to a third embodiment of the present disclosure. Fig. 6 is a circuit diagram showing a battery pack and a power source according to a fourth embodiment of the present disclosure. Fig. 7 is a circuit diagram showing a battery pack and a power source according to a fifth embodiment of the present disclosure.

[0011] First Embodiment A first embodiment of the present disclosure will now be described with reference to the accompanying drawings.

[0012] [Circuit Configuration] Figure 1 is a circuit diagram showing a battery pack 1 and a power source 2 according to a first embodiment of the present disclosure. In the first embodiment, the battery pack 1 is used as a drive source (power source) for driving an electric motorcycle. The electric motorcycle includes an electric drive motor that rotates drive wheels, and an inverter that is a motor control device that controls the electric drive motor. The battery pack 1 rotates the drive wheels by supplying power to the electric drive motor via the inverter. In the first embodiment, the battery pack 1 is detachably attached to the body of the electric motorcycle.

[0013] As shown in Fig. 1, a battery pack 1 is electrically connected to a power source 2 while removed from a vehicle body. The battery pack 1 is charged by receiving power from the power source 2. The battery pack 1 constitutes a charge control system 100 by being electrically connected to the power source 2 so as to be charged by the power source 2.

[0014] In the first embodiment, the power source 2 includes a charger 2A that is electrically connected to a commercial AC power source 2B and converts AC power supplied from the commercial AC power source 2B into DC power and outputs the DC power. The charger 2A may be installed in a location away from the vehicle body, for example, indoors or in a parking lot. The charger 2A is of a type that outputs a predetermined constant voltage. In other words, the charger 2A outputs a constant voltage regardless of the state of charge or temperature of the battery pack 1. The battery pack 1 is detachably and electrically connected to the charger 2A.

[0015] The battery pack 1 is placed in a chargeable state by being electrically connected to the charger 2A. The chargeable state of the battery pack 1 is released by being detached from the charger 2A. The battery pack 1 is placed in a dischargeable state by being detached from the charger 2A and electrically connected to the body of the electric motorcycle. The dischargeable state of the battery pack 1 is released by being detached from the body.

[0016] 1 , the battery pack 1 has a positive terminal 1a electrically connected to a high-potential terminal 2C of the charger 2A and a negative terminal 1b electrically connected to a ground terminal 2D of the charger 2A. When the battery pack 1 is electrically connected to the body of an electric motorcycle, the positive terminal 1a and the negative terminal 1b are each electrically connected to a terminal on the vehicle body side. More specifically, the positive terminal 1a is electrically connected to the high-potential terminal on the vehicle body side. The negative terminal 1b is also electrically connected to a ground terminal on the vehicle body side. By electrically connecting the positive terminal 1a and the negative terminal 1b of the battery pack 1 to terminals on the vehicle body side, power can be supplied to electrical components such as an inverter provided on the vehicle body.

[0017] The battery pack 1 includes a battery body 11 that can charge and discharge power. In the first embodiment, the battery body 11 is composed of a plurality of battery cells connected in series. The battery cells may be, for example, lithium ion batteries. The positive electrode of the battery body 11 is electrically connected to the positive electrode terminal 1a. The negative electrode of the battery body 11 is electrically connected to the negative electrode terminal 1b.

[0018] In the first embodiment, the battery pack 1 has a charge / discharge circuit 12 that electrically connects the positive electrode terminal 1a and the positive electrode of the battery body 11. The charge / discharge circuit 12 includes a charge circuit portion 13 that can allow or prohibit current from flowing from the charger 2A toward the battery body 11, and a discharge circuit portion 14 that can allow or prohibit current from flowing from the battery body 11 toward the vehicle body. The charge circuit portion 13 and the discharge circuit portion 14 are electrically connected to each other in series.

[0019] The charging circuit portion 13 includes a first electrical path 15 and a second electrical path 16. The first electrical path 15 and the second electrical path 16 are electrically connected in parallel to each other. The second electrical path 16 has a higher electrical resistance than the first electrical path 15. Specifically, the second electrical path 16 includes a resistor 16R that makes the electrical resistance of the second electrical path 16 higher than the electrical resistance of the first electrical path 15.

[0020] The first electrical path 15 and the second electrical path 16 each have a switching element 15a, 16a that switches between an electrically conductive state. The switching elements 15a, 16a each switch between a conductive state and a non-conductive state when a voltage is applied via a control device (described later). Hereinafter, the switching element 15a of the first electrical path 15 will be referred to as the "first switching element 15a." The switching element 16a of the second electrical path 16 will be referred to as the "second switching element 16a."

[0021] The first switching element 15a and the second switching element 16a are each a transistor. Specifically, the first switching element 15a and the second switching element 16a are each a FET (Field Effect Transistor), and more specifically, a MOSFET (Metal-Oxide Semiconductor Field-Effect Transistor).

[0022] The first switching element 15a and the second switching element 16a each have switching characteristics. More specifically, when a control device (described later) applies a voltage to the gate, the first switching element 15a and the second switching element 16a each switch to a conductive state in which conduction occurs between the source and drain. Furthermore, when the control device does not apply a voltage to the gate, the first switching element 15a and the second switching element 16a each switch to a non-conductive state in which conduction does not occur between the source and drain.

[0023] The first switching element 15a and the second switching element 16a each have diode characteristics. More specifically, the first switching element 15a and the second switching element 16a each allow current to flow from the source to the drain and prohibit current from flowing from the drain to the source. Therefore, when expressed as an equivalent circuit, the first switching element 15a and the second switching element 16a each have a switching portion that switches between a conductive state and a non-conductive state and a diode portion that is electrically connected in parallel to the switch portion and allows current to flow from the source to the drain (see FIG. 1 ).

[0024] The first switching element 15a and the second switching element 16a each have a source electrically connected to the battery body 11 and a drain connected to the positive terminal 1a. Therefore, the first switching element 15a and the second switching element 16a each allow current to flow from the battery body 11 toward the positive terminal 1a, regardless of whether a voltage is applied to the gate. Furthermore, the first switching element 15a and the second switching element 16a each allow current to flow from the positive terminal 1a toward the battery body 11 when a voltage is applied to the gate.

[0025] Resistor 16R included in second current path 16 may be any of a variety of resistors, such as a carbon film resistor, a metal film resistor, a metal oxide film resistor, a metal glaze resistor, a wire wound resistor, or a cement resistor. Therefore, by switching first switching element 15a to the non-conductive state and second switching element 16a to the conductive state, the current flowing from charger 2A to battery main body 11 can be limited compared to when first switching element 15a is switched to the conductive state and second switching element 16a is switched to the non-conductive state.

[0026] The discharge circuit portion 14 includes a third electric path 17 and a fourth electric path 18. The third electric path 17 and the fourth electric path 18 are electrically connected in parallel with each other. The fourth electric path 18 has a higher electrical resistance than the third electric path 17. Specifically, the fourth electric path 18 includes a resistor 18R that makes the electrical resistance of the fourth electric path 18 higher than the electrical resistance of the third electric path 17.

[0027] The third electrical path 17 and the fourth electrical path 18 each have a switching element 17a, 18a that switches the electrical conduction state, similar to the first electrical path 15 and the second electrical path 16. Hereinafter, the switching element 17a of the third electrical path 17 will be referred to as the third switching element 17a. Also, the switching element 18a of the fourth electrical path 18 will be referred to as the fourth switching element 18a.

[0028] The third switching element 17a and the fourth switching element 18a are transistors, more specifically, MOSFETs, similar to the first switching element 15a and the second switching element 16a. The third switching element 17a and the fourth switching element 18a each have a source electrically connected to the positive terminal 1a and a drain connected to the battery body 11. Therefore, the third switching element 17a and the fourth switching element 18a each allow current to flow from the positive terminal 1a toward the battery body 11, regardless of whether a voltage is applied to the gate. Furthermore, the third switching element 17a and the fourth switching element 18a each allow current to flow from the battery body 11 toward the positive terminal 1a when a voltage is applied to the gate.

[0029] In this embodiment, the charging circuit portion 13 and the discharging circuit portion 14 are arranged on a common substrate within the battery pack 1. The first switching element 15a, the second switching element 16a, the third switching element 17a, and the fourth switching element 18a may each be the same type of MOSFET. Furthermore, the resistor 16R of the second electrical path 16 and the resistor 18R of the fourth electrical path 18 may be the same type of resistor. As described above, arranging the charging circuit portion 13 and the discharging circuit portion 14 on a common substrate facilitates reducing the number of component types and costs. Furthermore, by using the same types of elements in the charging circuit portion 13 and the discharging circuit portion 14, the charging circuit portion 13 and the discharging circuit portion 14 can be realized by simply changing the connection orientation of each element.

[0030] The battery pack 1 includes a battery management unit 19 (hereinafter referred to as BMU). The BMU 19 is a control device for controlling the charge / discharge state of the battery 11. In the first embodiment, the BMU 19 controls the current flowing from the charger 2A to the battery 11 via the charge / discharge circuit 12. Specifically, the BMU 19 controls the first switching element 15a, the second switching element 16a, the third switching element 17a, and the fourth switching element 18a. More specifically, the BMU 19 selectively applies voltages to the gates of the first switching element 15a, the second switching element 16a, the third switching element 17a, and the fourth switching element 18a. The BMU 19 controls the switching elements 15a, 16a, 17a, and 18a to switch the switching elements 15a, 16a, 17a, and 18a between a conductive state and a non-conductive state. For example, the BMU 19 controls the current to flow from the charger 2A toward the battery main body 11 by switching the first switching element 15a or the second switching element 16a to the conductive state. The BMU 19 also controls the current to flow from the battery main body 11 toward the electrical components of the vehicle body by switching the third switching element 17a or the fourth switching element 18a to the conductive state.

[0031] In the first embodiment, the BMU 19 is an integrated circuit including a processor 19a (see FIG. 2 ) that performs arithmetic processing, a memory 19b (see FIG. 2 ) that stores arithmetic programs and arithmetic results, and an interface (not shown) that converts signals from various sensors (described later) into signals readable by the processor 19a and transmits the signals to the processor 19a, and applies voltages to the switching elements 15a, 16a, 17a, and 18a in accordance with the arithmetic results. The BMU 19 controls the switching elements 15a, 16a, 17a, and 18a based on the signals transmitted from the various sensors (described later) so as to enable charging and discharging of the battery 11 while preventing damage to the battery 11 and the charging / discharging circuit 12. The BMU 19 may also control the switching elements 15a, 16a, 17a, and 18a based on signals provided by a charger 2A connected to the battery pack 1 or a vehicle control device.

[0032] The battery pack 1 includes various sensors. Specifically, the battery pack 1 includes a first voltmeter 20, a second voltmeter 21, and an ammeter 22. The first voltmeter 20 detects the voltage between the terminals of the battery body 11, for example, the open-circuit voltage. The second voltmeter 21 detects the voltage applied to the battery pack 1 from the charger 2, i.e., the voltage applied to the charger 2A. The ammeter 22 detects the current flowing through the charge / discharge circuit 12. The first voltmeter 20, the second voltmeter 21, and the ammeter 22 are electrically connected to the BMU 19 so as to transmit detected information to the BMU 19 as a signal. The battery pack 1 also includes a temperature sensor 23 that detects the temperature inside the battery body. The battery pack 1 may also include other sensors, such as a sensor that detects physical connection with the charger 2A.

[0033] [Configuration of the Battery Management Unit] Figure 2 is a block diagram showing the BMU 19 in Figure 1. The functions performed by the components described herein may be implemented in circuitry or processing circuitry, including general-purpose processors, application-specific processors, integrated circuits, ASICs (Application Specific Integrated Circuits), CPUs (Central Processing Units), conventional circuits, and / or combinations thereof, programmed to perform the described functions. A processor includes transistors and other circuits and is considered to be circuitry or processing circuitry. A processor may also be a programmed processor that executes a program stored in memory. In this specification, circuitry, units, and means refer to hardware that is programmed to perform the described functions or hardware that executes them. The hardware may be any hardware disclosed herein or any hardware known to be programmed or capable of performing the described functions. If the hardware is a processor, the circuitry, means, or unit is a combination of hardware and software used to configure the hardware and / or processor.

[0034] The processor 19a includes a charge control unit 19c and a discharge control unit 19d. In the first embodiment, the charge control unit 19c is functionally realized by the processor 19a executing a charge control program stored in the memory 19b. The discharge control unit 19d is also functionally realized by the processor 19a executing a discharge control program stored in the memory 19b.

[0035] When the charge control unit 19c determines that predetermined charge limit conditions are satisfied, it controls the charge / discharge circuit 12 to limit the magnitude of the charge current flowing from the power source 2 to the battery main body 11. Specifically, the charge control unit 19c controls the first switching element 15a and the second switching element 16a to prohibit the current from flowing through the first electrical circuit 15 and to allow the current to flow through the second electrical circuit 16. When the current flows through the second electrical circuit 16, the electrical resistance of the second electrical circuit 16 is greater than the electrical resistance of the first electrical circuit 15, and therefore the charge current is limited and reduced compared to when the current flows through the first electrical circuit 15.

[0036] When the charge control unit 19c determines that a predetermined charge limit release condition is satisfied, it releases the limit on the magnitude of the charging current by controlling the charge / discharge circuit 12. Specifically, the charge control unit 19c controls the first switching element 15a and the second switching element 16a to permit the current to flow through the first electrical circuit 15 and to prohibit the current from flowing through the second electrical circuit 16. When the current flows through the first electrical circuit 15, the electrical resistance of the first electrical circuit 15 is smaller than the electrical resistance of the second electrical circuit 16. Therefore, the limit on the charging current is released and the charging current is larger than when the current flows through the second electrical circuit 16.

[0037] The charge control unit 19c determines whether the charge limiting condition is satisfied based on a signal transmitted from at least one of the first voltmeter 20, the second voltmeter 21, and the ammeter 22. In the first embodiment, the charge limiting condition is the start of charging of the battery 11. For example, when the second voltmeter 21 detects an increase in the applied voltage of the charger 2A and transmits the detected increase in applied voltage as a signal to the BMU 19, the charge control unit 19c determines that charging of the battery 11 has started. When charging of the battery 11 has started, the charge control unit 19c determines that the charge limiting condition is satisfied and limits the magnitude of the charging current.

[0038] The charge control unit 19c determines whether the charge limit release condition is satisfied based on a signal transmitted from at least one of the first voltmeter 20, the second voltmeter 21, and the ammeter 22. In the first embodiment, the charge limit release condition is at least one of the following: the potential difference between the battery main body 11 and the power source 2 becomes equal to or less than a predetermined potential difference threshold; the charging current becomes equal to or less than a predetermined charging current threshold; and the time spent charging the battery main body 11 with the magnitude of the charging current limited exceeds a predetermined time. When the charge control unit 19c determines whether any of the charge limit release conditions is satisfied based on the signal transmitted from at least one of the first voltmeter 20, the second voltmeter 21, and the ammeter 22, the charge control unit 19c releases the limit on the magnitude of the charging current because the charging current has reached a stable state.

[0039] The discharge control unit 19d limits the magnitude of the discharge current flowing from the battery main body 11 to the electrical components of the vehicle body by controlling the charge / discharge circuit 12. Specifically, the discharge control unit 19d controls the third switching element 17a and the fourth switching element 18a to prohibit the current from flowing through the third electrical circuit 17 and to allow the current to flow through the fourth electrical circuit 18. When the current flows through the fourth electrical circuit 18, the electrical resistance of the fourth electrical circuit 18 is greater than the electrical resistance of the third electrical circuit 17, and therefore the discharge current is limited and reduced compared to when the current flows through the third electrical circuit 17.

[0040] The discharge control unit 19d removes the restriction on the magnitude of the discharge current by controlling the charge / discharge circuit 12. Specifically, the discharge control unit 19d controls the third switching element 17a and the fourth switching element 18a to permit the current to flow through the third electrical circuit 17 and to prohibit the current from flowing through the fourth electrical circuit 18. When the current flows through the third electrical circuit 17, the electrical resistance of the third electrical circuit 17 is smaller than the electrical resistance of the fourth electrical circuit 18, and therefore the restriction on the discharge current is removed and the discharge current becomes larger than when the current flows through the fourth electrical circuit 18.

[0041] The memory 19b of the BMU 19 stores a charge control program and a discharge control program for executing the functions of the charge control unit 19c and the discharge control unit 19d.

[0042] The processor 19a executes a charge control program and a discharge control program stored in the memory 19b to realize the functions of a charge control unit 19c and a discharge control unit 19d.

[0043] In this embodiment, the processor 19a is an integrated circuit, but may be a microprocessor that integrates the functions of the charge control unit 19c and the discharge control unit 19d.

[0044] [Charging Method] Figure 3 is a flowchart showing a charging method by the BMU 19 of Figure 2. When the battery pack 1 is in a standby state, i.e., not in a charging state or a discharging state, the charging control unit 19c proceeds to step S1 to start charging. When the battery pack 1 is in a standby state, the charging control unit 19c controls the first switching element 15a and the second switching element 16a to prevent current from flowing from the charger 2A to the battery main body 11. Specifically, the charging control unit 19c switches the first switching element 15a and the second switching element 16a to a non-conductive state. In other words, the charging control unit 19c maintains a state in which no voltage is applied to the gates of the first switching element 15a and the second switching element 16a. By keeping the first switching element 15a and the second switching element 16a in a non-conductive state, current is prevented from flowing from the charger 2A to the battery main body 11 via the first electrical path 15 and the second electrical path 16.

[0045] In step S1, the charge control unit 19c determines whether the charge limiting condition is satisfied. When the charge control unit 19c determines whether the charge limiting condition is satisfied (YES in step S1), the control process proceeds to step S2. For example, the charge control unit 19c determines whether charging of the battery main body 11 has started based on a change in the signal received from the second voltmeter 21, and determines whether the charge limiting condition is satisfied. Specifically, when the second voltmeter 21 detects an increase in the applied voltage of the charger 2A and transmits the detected increase in applied voltage as a signal to the BMU 19, the charge control unit 19c determines that charging of the battery main body 11 has started. When the charge control unit 19c does not determine whether the charge limiting condition is satisfied (NO in step S1), the control process repeats step S1.

[0046] In step S2, the charge control unit 19c determines whether to start charging the battery pack 11. The charge control unit 19c determines whether the charge start conditions for starting charging are satisfied based on the state of charge (SOC) of the battery 11, the state of health (SOH) of the battery 11, the temperature inside the battery pack, the presence or absence of abnormalities in various sensors, and the like, which are obtained from signals transmitted from the first voltmeter 20, the second voltmeter 21, the ammeter 22, and the temperature sensor 23. For example, if the battery 11 exceeds a predetermined upper charge limit, the charge control unit 19c determines that the charge start conditions are not satisfied (NO in step S2) to prevent overcharging of the battery, and the control process proceeds to step S7, where charging is terminated. If the charge control unit 19c determines that the charge start conditions are satisfied (YES in step S2), the control process proceeds to step S3.

[0047] In step S3, the charging control unit 19c limits the charging current flowing from the power source 2 to the battery 11, as described above, to charge the battery 11. The charging control unit 19c maintains the first switching element 15a in a non-conductive state and switches the second switching element 16a to a conductive state. In other words, the charging control unit 19c maintains a state in which no voltage is applied to the gate of the first switching element 15a and applies a voltage to the gate of the second switching element 16a. Therefore, the charging current is prohibited from flowing through the first electrical circuit 15 and is permitted to flow from the charger 2A to the battery 11 via the second electrical circuit 16. When the battery 11 is being charged with the charging current limited, the control process proceeds to step S4.

[0048] In step S4, the charge control unit 19c determines whether the charge limit release condition is satisfied. When the charge control unit 19c determines whether the charge limit release condition is satisfied (YES in step S4), the control process proceeds to step S5. For example, the charge control unit 19c determines whether the charge limit release condition is satisfied based on a change in a signal transmitted from at least one of the first voltmeter 20, the second voltmeter 21, and the ammeter 22. Specifically, the charge control unit 19c determines whether at least one of the following conditions is satisfied: the potential difference between the battery main body 11 and the power source 2A is equal to or less than a predetermined potential difference threshold; the charging current is equal to or less than a predetermined charging current threshold; or the time required to charge the battery main body 11 with the limited charging current exceeds a predetermined time, based on the open-circuit voltage of the battery main body 11 detected by the first voltmeter 20, the applied voltage of the power source 2A detected by the second voltmeter 21, and the charging current flowing through the charge / discharge circuit 12 detected by the ammeter 22. When the charge control unit 19c does not determine that the charge restriction release condition is satisfied (NO in step S4), the control process returns to step S3, and steps S3 and S4 are repeated.

[0049] In step S5, the charging control unit 19c, as described above, releases the restriction on the charging current flowing from the power source 2 to the battery 11 and continues charging the battery 11. The charging control unit 19c switches the first switching element 15a to a conductive state and the second switching element 16a to a non-conductive state. In other words, the charging control unit 19c applies a voltage to the gate of the first switching element 15a and stops applying a voltage to the gate of the second switching element 16a. Therefore, the charging current is permitted to flow from the charger 2A through the first electrical circuit 15 to the battery 11, and the charging current is prohibited from flowing through the second electrical circuit 16. When charging is performed with the charging current restriction released, the control process proceeds to step S6.

[0050] In step S6, the charge control unit 19c determines whether or not to terminate charging of the battery 11. The charge control unit 19c determines whether or not a charge termination condition for terminating charging is satisfied based on the state of charge (SOC) of the battery, the state of health (SOH) of the battery, the temperature inside the battery pack 11, the presence or absence of abnormalities in various sensors, and the like. For example, when the battery reaches a predetermined upper charge limit, the charge control unit 19c determines that the charge termination condition is satisfied (YES in step S6) to prevent overcharging of the battery 11, and the control process proceeds to step S7 to terminate charging. When the charge control unit 19c determines that the charge termination condition is not satisfied (NO in step S6), the control process returns to step S5, and steps S5 and S6 are repeated.

[0051] In step S7, the charging control unit 19c controls the first switching element 15a and the second switching element 16a to prevent current from flowing from the charger 2A toward the battery main body 11. Specifically, the charging control unit 19c switches the first switching element 15a and the second switching element 16a to a non-conductive state. In other words, the charging control unit 19c stops applying voltage to the gates of the first switching element 15a and the second switching element 16a. With the first switching element 15a and the second switching element 16a in a non-conductive state, current is prohibited from flowing from the charger 2A toward the battery main body 11 via the first electrical circuit 15 and the second electrical circuit 16. Once the charging control unit 19c has controlled the battery pack 1 to prevent current from flowing from the charger 2A toward the battery main body 11, the battery pack 1 transitions to a standby state and charging is terminated.

[0052] Charging of the battery pack 1 is performed according to the flow including steps S1 to S7. Furthermore, when proceeding to the next step after satisfying the conditions in steps S1, S2, and S4, another process may be interposed between the steps, or a waiting time may be set before proceeding to the next step.

[0053] The charge control unit 19c may determine whether a predetermined charge termination condition, such as removing the battery pack 1 from the charger 2A, is satisfied while the process of each step is being performed. If the charge control unit 19c determines that the charge termination condition is satisfied, the charge control unit 19c terminates the charge. The charge termination condition may include other conditions. For example, the charge termination condition may include an abnormality in various sensors, a temperature increase inside the battery pack 11, or battery deterioration exceeding a predetermined amount.

[0054] In the above-described step S1, for example, if the battery pack 1 has a sensor that detects the physical connection with the charger 2A, the charge control unit 19c may determine that charging of the battery main body 11 has started based on the physical connection between the battery pack 1 and the charger 2A, and determine whether the charge limit condition is satisfied. Also, for example, if the charger 2A transmits a signal including a charge start command to the battery pack 1, the charge control unit 19c may determine that charging of the battery main body 11 has started based on the signal including the charge start command, and determine whether the charge limit condition is satisfied. Furthermore, for example, the charge control unit 19c may determine that an excessively large current flows from the charger 2A to the battery main body 11 in a short period of time, and determine whether the charge limit condition is satisfied.

[0055] [Operation and Effect] The battery pack 1 including the BMU 19 configured in this manner has the following features.

[0056] The charge control system 100 of the first embodiment comprises: a battery body 11 that can be charged and discharged; a power source 2 that generates electric power; a charging circuit portion 13 that electrically connects the power source 2 and the battery body 11 so that the power source 2 charges the battery body 11, the charging circuit portion 13 being capable of limiting the magnitude of the charging current flowing from the power source 2 to the battery body 11; and a BMU 19 that controls the charging circuit portion 13; when the BMU 19 determines that predetermined charging limit conditions are met, the BMU 19 controls the charging circuit portion 13 to limit the magnitude of the charging current, and when the BMU 19 determines that predetermined charging limit release conditions are met, the BMU 19 controls the charging circuit portion 13 to release the limit on the magnitude of the charging current.

[0057] According to the first embodiment, the BMU 19 of the charge control system 100 controls the charging circuit unit 13 to limit the magnitude of the charging current when it determines that a predetermined charging limit condition is satisfied. Limiting the magnitude of the charging current helps prevent damage to the battery 11 and the charging circuit unit 13. Furthermore, the BMU 19 of the charge control system 100 controls the charging circuit unit 13 to release the limit on the magnitude of the charging current when it determines that a charging limit release condition is satisfied. By releasing the limit on the magnitude of the charging current, the charging current can be increased compared to when the magnitude of the charging current is limited, thereby reducing the charging time of the battery 11. Furthermore, because the BMU 19 controls the magnitude of the charging current in the charge control system 100, the power source 2 that charges the battery 11 does not need to have a function for adjusting the power supplied to the battery 11 according to the battery 11. Therefore, the charge control system 100 increases the versatility of the power source 2 that can be used, making it easy to charge using various power sources 2.

[0058] Furthermore, according to the first embodiment, the BMU 19 of the charge control system 100 can limit the charging current flowing at the start of charging. By limiting the charging current flowing at the start of charging, the battery 11 and the charging circuit 13 can withstand excessive current at the start of charging. This eliminates the need to set excessively large allowable currents for the electrical elements of the battery pack 1, making it easier to reduce the manufacturing cost of the battery pack 1. Furthermore, according to the first embodiment, the charge control system 100 can charge using various power sources 2, improving user convenience. For example, it is possible to use other types of battery packs and chargers, and to use general-purpose chargers. Furthermore, according to the first embodiment, by limiting the charging current flowing at the start of charging, it is easier to use a charger 2A capable of outputting a relatively high voltage. Using a charger 2A capable of outputting a relatively high voltage makes it easier to further shorten the charging time of the battery 11 while preventing damage to the battery 11 and the charging circuit 13. Furthermore, according to the first embodiment, the BMU 19 of the charging control system 100 controls the second switching element 16a to prohibit the charging current from flowing through the second circuit 16, thereby preventing power consumption in the resistor 16R and improving the charging efficiency of the charging control system 100.

[0059] The charging circuit portion 13 also has a first electrical circuit 15 including a first switching element 15a, and a second electrical circuit 16 electrically connected in parallel to the first electrical circuit 15 and including a resistor 16R that makes the electrical resistance of the second electrical circuit 16 greater than the electrical resistance of the first electrical circuit 15. The BMU 19 controls the first switching element 15a to open when it determines that the charging limiting condition is met, and controls the first switching element 15a to close when it determines that the charging limit release condition is met.

[0060] According to the first embodiment, when the BMU 19 determines whether the charge limit condition is satisfied, it prohibits the charging current from flowing through the first electrical circuit 15 and allows the charging current to flow through the second electrical circuit 16. The second electrical circuit 16 has a higher electrical resistance than the first electrical circuit 15, so it can limit the excessive current flowing from the charger 2A to the battery 11 at the start of charging. Furthermore, when the BMU 19 determines whether the charge limit release condition is satisfied, it allows the charging current to flow through the first electrical circuit 15 and prohibits the charging current from flowing through the second electrical circuit 16. The first electrical circuit 15 has a lower electrical resistance than the second electrical circuit 16, so it can release the limit on the charging current flowing from the charger 2A to the battery 11. Therefore, by releasing the limit on the charging current when the charging current is smaller than at the start of charging, it is possible to increase the charging current flowing from the charger 2A to the battery 11 and improve the charging efficiency of the charging control system 100.

[0061] The first switching element 15a also includes a switching portion that switches the first switching element 15a between a conductive state and a non-conductive state, and a diode portion that is electrically connected in parallel to the switching portion and allows charging current to flow from the battery main body 11.

[0062] According to the first embodiment, since the first switching element 15a has a diode portion, the battery main body 11 can be discharged regardless of the state of the first switching element 15a.

[0063] The charging limiting condition is that charging of the battery main body 11 is started.

[0064] According to the first embodiment, the charge limiting condition is that charging of the battery main body 11 is started, so that the excess current flowing from the charger 2A to the battery main body 11 at the start of charging can be limited.

[0065] The condition for releasing the charging restriction is at least one of the following: the potential difference between the battery body 11 and the power source 2 becomes equal to or less than a predetermined potential difference threshold; the charging current becomes equal to or less than a predetermined charging current threshold; and the time for charging the battery body 11 by limiting the magnitude of the charging current exceeds a predetermined time.

[0066] According to the first embodiment, the BMU 19 determines whether to release the charge current restriction based on the detected value of the electrical condition or the passage of time, and therefore it is easy to release the charge current restriction when the charge current has decreased and stabilized, and it is easy to prevent the charge current restriction from becoming insufficient.

[0067] Furthermore, the charging method of the first embodiment includes the steps of: when determining whether a predetermined charging limiting condition is satisfied, electrically connecting the power source 2 and the battery main body 11 so that the power source 2 charges the battery main body 11, and controlling a charging circuit portion 13 that can limit the magnitude of the charging current flowing from the power source 2 to the battery main body 11, thereby limiting the magnitude of the charging current; and when determining whether a predetermined charging limit release condition is satisfied, controlling the charging circuit portion 13 to release the limit on the magnitude of the charging current.

[0068] According to the first embodiment, the charging control method controls the charging circuit portion 13 to limit the magnitude of the charging current flowing from the charger 2A to the battery 11 when determining whether the charging limit condition is satisfied. Limiting the magnitude of the charging current makes it easier to prevent damage to the battery 11 and the charging circuit portion 13. Furthermore, the charging control method controls the charging circuit portion 13 to remove the limit on the magnitude of the charging current when determining whether the charging limit removal condition is satisfied. By removing the limit on the magnitude of the charging current, the charging current can be increased compared to when the magnitude of the charging current is limited, making it easier to shorten the charging time of the battery 11. Furthermore, because the charging control method controls the magnitude of the charging current, the power source 2 that charges the battery 11 does not need to have a function to adjust the power supplied depending on the battery 11. Therefore, the charging control system 100 is more versatile in terms of the power source 2 that can be used, making it easier to charge using various power sources 2.

[0069] Second Embodiment A second embodiment of the present disclosure will be described below with reference to Fig. 4. Description of the content common to the first embodiment will be omitted. Also, reference numerals common to the first embodiment will be replaced with reference numerals with a value obtained by adding 100.

[0070] 4 is a circuit diagram showing a battery pack 101 and a power source 102 according to a second embodiment of the present disclosure. The battery pack 101 is attached to a body 130 of an electric motorcycle and is electrically connected to the power source 102. Specifically, the battery pack 101 is electrically connected to a charging connector 140 attached to the body, and is electrically connected to a charger 102A via the charging connector 140, thereby becoming chargeable by power supplied from a commercial AC power source 2B.

[0071] As shown in FIG. 4, the charging connector 140 has a positive terminal 141a electrically connected to the high potential side terminal 102C of the charger 102A, and a negative terminal 141b electrically connected to the ground side terminal 102D of the charger 102A.

[0072] The electric motorcycle includes a drive electric motor 150 that rotates the drive wheels, and an inverter 160 that is a motor control device that controls the drive electric motor 150. The inverter 160 is electrically connected in parallel to the battery pack 101. The battery pack 101 and the inverter 160 are electrically connected to a control unit 170 of the electric motorcycle, and receive signals transmitted from the control unit 170. The control unit 170 is electrically connected to vehicle-side sensors 180 that include various sensors attached to the vehicle body, and receives signals transmitted from the vehicle-side sensors 180.

[0073] The inverter 160 has a capacitor that stores power supplied from the battery pack 101 to the electric drive motor 150 when the electric motorcycle is driven, or power supplied from the electric drive motor 150 to the battery pack 101 when the electric motorcycle is regenerative braking. When power remains in the capacitor and the battery pack 101 is charged by the power source 102 via the charging connector 140, excessive current from the capacitor and the power source 102 may flow toward the battery pack 101. If the battery pack 101 of the second embodiment has a configuration similar to that of the battery pack 1 of the first embodiment, even if excessive current from the capacitor and the power source 102 flows toward the battery pack 101, damage to the battery itself and the charging circuit can be easily prevented by limiting the magnitude of the charging current. Therefore, the battery pack 101 is easily protected electrically even when it is charged while attached to the body of the electric motorcycle.

[0074] [Third Embodiment] A third embodiment of the present disclosure will be described below with reference to Fig. 5. Description of content common to the first embodiment will be omitted. Also, reference numerals common to the first embodiment will be replaced with reference numerals with a value obtained by adding 200.

[0075] 5 is a circuit diagram showing a battery pack 201 and a power source 202 according to a third embodiment of the present disclosure. A charge / discharge circuit 212 of the battery pack 201 includes a charge circuit portion and a discharge circuit portion as a common circuit. The charge / discharge circuit 212 includes a first electrical path 215 and a second electrical path 216. The first electrical path 215 and the second electrical path 216 are electrically connected in parallel with each other. The second electrical path 216 has a higher electrical resistance than the first electrical path 215. Specifically, the second electrical path 216 includes a resistor 216R that makes the electrical resistance of the second electrical path 216 higher than the electrical resistance of the first electrical path 215.

[0076] The charge / discharge circuit 212 of the third embodiment differs from the first embodiment in that the second electrical circuit 216 does not have a switching element, while the first electrical circuit 215 has a first switching element 215a.

[0077] When the charge control unit 219c of the BMU 219 determines that predetermined charge limit conditions are met, it controls the charge / discharge circuit 212 to limit the magnitude of the charge current flowing from the power source 202 to the battery main body 211. Specifically, the charge control unit 219c controls the first switching element 215a to prohibit the current from flowing through the first electrical circuit 215. By prohibiting the current from flowing through the first electrical circuit 215, the current flows through the second electrical circuit 216. When the current flows through the second electrical circuit 216, the electrical resistance of the second electrical circuit 216 is greater than the electrical resistance of the first electrical circuit 215, and therefore the charge current is limited and reduced compared to when the current flows through the first electrical circuit 215.

[0078] When the charge control unit 219c determines that a predetermined charge limit release condition is satisfied, it controls the charge / discharge circuit 212 to release the limit on the magnitude of the charging current. Specifically, the charge control unit 219c controls the first switching element 215a to allow the current to flow through the first electrical circuit 215. By allowing the current to flow through the first electrical circuit 215, the current flows through the first electrical circuit 215, which has a lower electrical resistance than the second electrical circuit 216. When the current flows through the first electrical circuit 215, the electrical resistance of the first electrical circuit 215 is lower than the electrical resistance of the second electrical circuit 216, and therefore the limit on the charging current is released and the current becomes larger than when the current flows through the second electrical circuit 216.

[0079] According to the third embodiment, the BMU 219 of the charge control system 300 controls the charge / discharge circuit 212 to limit the magnitude of the charging current when it determines that a predetermined charging limit condition is satisfied. Limiting the magnitude of the charging current helps prevent damage to the battery 211 and the charging circuit 213. Furthermore, the BMU 219 of the charge control system 300 controls the charge / discharge circuit 212 to remove the limit on the magnitude of the charging current when it determines that a charging limit removal condition is satisfied. By removing the limit on the magnitude of the charging current, the charging current can be increased compared to when the magnitude of the charging current is limited, thereby reducing the charging time of the battery 211. Furthermore, because the BMU 219 controls the magnitude of the charging current in the charge control system 300, the power source 202 that charges the battery 211 does not need to have a function for adjusting the power supplied depending on the battery 211. Therefore, the charge control system 300 increases the versatility of the power source 202 that can be used, making it easy to charge using various power sources 202.

[0080] [Fourth Embodiment] A fourth embodiment of the present disclosure will be described below with reference to Fig. 6. Description of the content common to the first embodiment will be omitted. Furthermore, reference numerals common to the first embodiment will be replaced with reference numerals with a value obtained by adding 300.

[0081] 6 is a circuit diagram showing a battery pack 301 and a power source 302 according to a fourth embodiment of the present disclosure. A charge / discharge circuit 312 of the battery pack 301 includes a charge circuit portion and a discharge circuit portion as a common circuit. Unlike the first embodiment, the charge / discharge circuit 312 of the fourth embodiment does not include any circuits electrically connected in parallel, but includes a single variable resistor 312R.

[0082] When the charge control unit 319c of the BMU 319 determines whether a predetermined charge limiting condition is satisfied, it controls the charge / discharge circuit 312 to limit the magnitude of the charge current flowing from the power source 302 to the battery main body 311. Specifically, the charge control unit 319c controls the variable resistor 312R to increase the electrical resistance of the charge / discharge circuit 312. As the electrical resistance of the charge / discharge circuit 312 increases, the charge current flowing through the charge / discharge circuit 312 is limited and reduced.

[0083] When the charge control unit 319c determines that a predetermined charge restriction release condition is satisfied, it releases the restriction on the magnitude of the charging current by controlling the charge / discharge circuit 312. Specifically, the charge control unit 319c controls the variable resistor 312R to reduce the electrical resistance of the charge / discharge circuit 312. As the electrical resistance of the charge / discharge circuit 312 decreases, the restriction on the charging current flowing through the charge / discharge circuit 312 is released and the charging current increases.

[0084] According to the fourth embodiment, the BMU 319 of the charge control system 400 controls the charge / discharge circuit 312 to limit the magnitude of the charging current when it determines that a predetermined charging limit condition is met. Limiting the magnitude of the charging current helps prevent damage to the battery 311 and the charging circuit 313. Furthermore, the BMU 319 of the charge control system 400 controls the charge / discharge circuit 312 to remove the limit on the magnitude of the charging current when it determines that a charging limit removal condition is met. By removing the limit on the magnitude of the charging current, the charging current can be increased compared to when the magnitude of the charging current is limited, thereby reducing the charging time of the battery 311. Furthermore, because the BMU 319 controls the magnitude of the charging current in the charge control system 400, the power source 302 that charges the battery 311 does not need to have a function for adjusting the power supplied depending on the battery 311. Therefore, the charge control system 400 increases the versatility of the power source 302 that can be used, making it easy to charge using various power sources 302.

[0085] Fifth Embodiment A fifth embodiment of the present disclosure will be described below with reference to Fig. 7. Description of the content common to the first embodiment will be omitted. Also, the reference numerals common to the first embodiment will be replaced with reference numerals with 400 added.

[0086] 7 is a circuit diagram showing a battery pack 401 and a power source 402 according to a fifth embodiment of the present disclosure. The battery pack 401 is electrically connected to the power source 402 in a state where it is removed from the vehicle body. Unlike the first embodiment, the battery pack 401 of the fifth embodiment does not have a charge / discharge circuit.

[0087] A positive terminal 401a of the battery pack 401 is electrically connected to a high potential side terminal 402C of the charger 402A via a charge / discharge circuit 412 arranged outside the battery pack 401. A negative terminal 401b of the battery pack 401 is electrically connected to a ground side terminal 402D of the charger 402A, as in the first embodiment.

[0088] The charge / discharge circuit 412 includes a charge circuit portion and a discharge circuit portion as a common circuit. The charge / discharge circuit 412 includes a first electrical circuit 415 and a second electrical circuit 416. The first electrical circuit 415 and the second electrical circuit 416 are electrically connected in parallel to each other. The second electrical circuit 416 has a higher electrical resistance than the first electrical circuit 415. Specifically, the second electrical circuit 416 includes a resistor 416R that makes the electrical resistance of the second electrical circuit 416 higher than the electrical resistance of the first electrical circuit 415.

[0089] The first and second electrical paths 415 and 416 have a first switching element 415a and a second switching element 416a, respectively, that switch the electrical conduction state. The first and second switching elements 415a and 416a are disposed externally and electrically connected to the charging control device 470, and receive signals transmitted from the charging control device 470. The charging control device 470 is electrically connected to a charging control device side sensor 480, which includes various sensors attached to the vehicle body, and receives signals transmitted from the charging control device side sensor 480.

[0090] When the charge control device 470 determines that predetermined charge limit conditions are met, it controls the charge / discharge circuit 412 to limit the magnitude of the charging current flowing from the power source 402 to the battery main body 411. Specifically, the charge control device 470 controls the first switching element 415a and the second switching element 416a to prohibit the current from flowing through the first electrical circuit 415 and to allow the current to flow through the second electrical circuit 416. When the current flows through the second electrical circuit 416, the electrical resistance of the second electrical circuit 416 is greater than the electrical resistance of the first electrical circuit 415, and therefore the charging current is limited and reduced compared to when the current flows through the first electrical circuit 415.

[0091] When the charge control device 470 determines that a predetermined charge limit release condition is satisfied, it controls the charge / discharge circuit 412 to release the limit on the magnitude of the charging current. Specifically, the charge control device 470 controls the first switching element 415a and the second switching element 416a to allow current to flow through the first electrical circuit 415 and to prohibit current from flowing through the second electrical circuit 416. When current flows through the first electrical circuit 415, the electrical resistance of the first electrical circuit 415 is smaller than the electrical resistance of the second electrical circuit 416, and therefore the limit on the charging current is released and the charging current is larger than when the current flows through the second electrical circuit 416.

[0092] According to the fifth embodiment, the BMU 419 of the charge control system 500 controls the charge / discharge circuit 412 to limit the magnitude of the charging current when it determines that predetermined charging limit conditions are met. Limiting the magnitude of the charging current helps prevent damage to the battery 411 and the charging circuit 413. Furthermore, the BMU 419 of the charge control system 500 controls the charge / discharge circuit 412 to remove the limit on the magnitude of the charging current when it determines that charging limit removal conditions are met. By removing the limit on the magnitude of the charging current, the charging current can be increased compared to when the magnitude of the charging current is limited, thereby reducing the charging time of the battery 411. Furthermore, because the BMU 419 controls the magnitude of the charging current in the charge control system 500, the power source 402 that charges the battery 411 does not need to have a function for adjusting the power supplied depending on the battery 411. Therefore, the charge control system 500 increases the versatility of the power source 402 that can be used, making it easy to charge using various power sources 402.

[0093] Other Embodiments The present disclosure is not limited to the configurations of the above-described embodiments, and various modifications are possible.

[0094] In the above-described embodiments, particularly the first embodiment, the charging circuit portion 13 and the discharging circuit portion 14 are electrically connected in series to each other, but they may also be electrically connected in parallel, for example.

[0095] In the above-described embodiments, the charge / discharge circuits 12, 212, 312, and 412 include a charge circuit portion and a discharge circuit portion, but may include only a charge circuit portion.

[0096] In the above-described embodiments, the charging control systems 100, 300, 400, and 500 are equipped with various sensors used to determine the charging restriction conditions and the charging restriction release conditions, but may also be equipped with only a single sensor, for example, at least one of the first voltmeter 20, 220, and 320, the second voltmeter 21, 221, and 321, and the ammeter 22, 222, and 322.

[0097] In the above-described embodiment, the battery body 11, 211, 311 is configured with a plurality of battery cells connected in series, but this is not limited thereto. For example, the battery body 11, 211, 311 may be configured with a plurality of battery cells connected in parallel. The battery body 11 only needs to include at least one battery cell. Furthermore, although the battery cells are described as being lithium-ion batteries, this is not limited thereto. The battery cells may be known batteries such as lead-acid batteries, nickel-metal hydride batteries, nickel-cadmium batteries, and all-solid-state batteries.

[0098] In the above-described embodiment, the first switching elements 15 a, 215 a, 415 a, the second switching elements 16 a, 416 a, the third switching element 17 a, and the fourth switching element 18 a are each a MOSFET, but this is not limiting. Each switching element may be an active element that can be controlled by a control device, and may be a relay-type switching element such as a mechanical relay or a solid-state relay.

[0099] In the above-described embodiment, the battery pack 1 is attached to an electric motorcycle, but this is not limiting. The battery pack is preferably used as a drive source (power source) for a vehicle that requires a large battery capacity. For example, the battery pack may be attached to an electrically driven vehicle other than a motorcycle, such as a tricycle or four-wheel vehicle, a water vehicle, or an aircraft. Furthermore, the battery pack 1 is not limited to being used for a vehicle, and may be used to rotate a rotating machine or to drive electrical components other than a rotating machine.

[0100] In the above-described embodiments, particularly the first embodiment, the memory 19b of the BMU 19 stores a charging control program for executing the charging method, but this is not limiting. For example, the charging control program may be stored in a recording medium such as a CD, a DVD, or a flash memory.

[0101] The present disclosure is not limited to electric vehicles, but can also be applied to hybrid vehicles that have a mode in which they run using a motor.

[0102] A first aspect of the present disclosure provides a charging control system comprising: a rechargeable battery body; a power source that generates electric power; a charging circuit that electrically connects the power source and the battery body so that the power source charges the battery body, the charging circuit being capable of limiting the magnitude of the charging current flowing from the power source to the battery body; and a charging control device that controls the charging circuit, wherein the charging control device controls the charging circuit to limit the magnitude of the charging current when it determines that predetermined limiting conditions are met, and controls the charging circuit to release the limit on the magnitude of the charging current when it determines that predetermined limit release conditions are met.

[0103] A second aspect of the present disclosure provides a charging control system according to the first aspect, wherein the charging circuit has: a first electrical path including a switching element; and a second electrical path electrically connected in parallel to the first electrical path, the second electrical path including a resistor that makes the electrical resistance of the second electrical path greater than the electrical resistance of the first electrical path; and the charging control device controls the switching element to open when it determines that the restriction condition is satisfied, and controls the switching element to close when it determines that the restriction release condition is satisfied.

[0104] A third aspect of the present disclosure provides a charging control system according to the second aspect, wherein the switching element includes a switching portion that switches the switching element between a conductive state and a non-conductive state, and a diode portion that is electrically connected in parallel to the switching portion and allows current to flow from the battery body.

[0105] A fourth aspect of the present disclosure provides the charge control system according to any one of the first to third aspects, wherein the limiting condition is that charging of the battery body is started.

[0106] A fifth aspect of the present disclosure provides a charging control system according to any one of the first to fourth aspects, wherein the restriction release condition is at least one of the following: the potential difference between the battery body and the power source is equal to or less than a predetermined potential difference threshold; the charging current is equal to or less than a predetermined charging current threshold; and the time required to charge the battery body by restricting the magnitude of the charging current exceeds a predetermined time.

[0107] A sixth aspect of the present disclosure provides a charging method comprising: when determining whether a predetermined limiting condition is satisfied, limiting the magnitude of the charging current by controlling a charging circuit that electrically connects a power source and a battery body so that the power source charges the battery body and can limit the magnitude of the charging current flowing from the power source to the battery body; and when determining whether a predetermined limit release condition is satisfied, releasing the limit on the magnitude of the charging current by controlling the charging circuit.

[0108] 2 Power source 11 Battery body 12 Charging / discharging circuit (charging circuit) 19 Battery management unit (charging control device) 100 Charging control system

Claims

1. A charging control system comprising: a rechargeable and dischargeable battery body; a power source that generates electric power; a charging circuit that electrically connects the power source and the battery body so that the power source charges the battery body, the charging circuit being capable of limiting a magnitude of a charging current flowing from the power source to the battery body; and a charging control device that controls the charging circuit, wherein the charging control device controls the charging circuit to limit the magnitude of the charging current when it determines that predetermined limiting conditions are satisfied, and releases the limit on the magnitude of the charging current by controlling the charging circuit when it determines that predetermined limit release conditions are satisfied.

2. The charging control system of claim 1, wherein the charging circuit has a first electric circuit including a switching element, and a second electric circuit electrically connected in parallel to the first electric circuit, the second electric circuit including a resistor that makes the electrical resistance of the second electric circuit greater than the electrical resistance of the first electric circuit, and the charging control device controls the switching element to open when it determines that the limiting condition is satisfied, and controls the switching element to close when it determines that the limit release condition is satisfied.

3. A charging control system as described in claim 2, wherein the switching element includes: a switching portion that switches the switching element between a conductive state and a non-conductive state; and a diode portion that is electrically connected in parallel to the switching portion and allows current to flow from the battery body.

4. A charging control system according to any one of claims 1 to 3, wherein the limiting condition is that charging of the battery body is started.

5. A charging control system as described in any one of claims 1 to 4, wherein the restriction release condition is at least one of: the potential difference between the battery body and the power source becoming equal to or lower than a predetermined potential difference threshold; the charging current becoming equal to or lower than a predetermined charging current threshold; and the time for charging the battery body by limiting the magnitude of the charging current exceeding a predetermined time.

6. A charging method comprising: when determining whether a predetermined limiting condition is satisfied, controlling a charging circuit that electrically connects a power source and the battery body so that the power source charges the battery body, and can limit the magnitude of the charging current flowing from the power source to the battery body, thereby limiting the magnitude of the charging current; when determining whether a predetermined limit release condition is satisfied, releasing the limit on the magnitude of the charging current by controlling the charging circuit.

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