JP6422401B2 - Charger - Google Patents

Description

  The present invention relates to a charger for charging a battery.

  As a charger for charging the battery in the battery pack, a microcomputer for charge control acquires battery temperature information from a thermistor provided in the vicinity of the battery in the battery pack, and performs charging based on the acquired temperature information. Chargers configured to perform control are known.

  Patent Document 1 discloses a charging apparatus configured to charge a battery by supplying a charging current when the temperature of the battery is within a chargeable temperature range based on temperature information acquired from a thermistor in the battery pack. Is disclosed.

JP 2006-288150 A

  When the thermistor in the battery pack breaks down, the temperature information acquired from the thermistor may become erroneous information indicating a temperature different from the actual battery temperature. And if the microcomputer of a charger recognizes the temperature of a battery based on the error information, it becomes impossible to control the charging of the battery normally.

  For example, even though the actual temperature of the battery is a low temperature outside the chargeable range, the microcomputer of the charger misrecognizes that the temperature of the battery is within the chargeable temperature range due to the influence of the thermistor failure, The battery may be charged.

  The present invention has been made in view of the above problems, and even if the temperature information indicating the temperature of the battery acquired from the battery pack is information indicating a temperature different from the actual temperature of the battery, the actual battery An object of the present invention is to provide a charger capable of performing appropriate charge control according to the temperature of the battery.

  1st aspect of this invention made | formed in order to solve the said subject is a charger which can attach or detach a battery pack, Comprising: A charging part, a temperature input terminal, a charger temperature detection part, and a charge availability judgment part With.

  The charging unit generates a charging current for charging the battery in the battery pack. When the battery pack is attached to the charger, the temperature input terminal receives a battery temperature detection signal indicating the temperature of the battery from the battery pack. The charger temperature detection unit detects a charger temperature that is an internal or external temperature of the charger. The chargeability determination unit has a battery temperature detection value that is equal to or higher than a first specified value and that is detected by the charger temperature detection unit. Is determined to be equal to or higher than a second specified value lower than the first specified value, output of a charging current from the charging unit to the battery pack is permitted, and the battery temperature detection value is equal to or higher than the first specified value. If it is determined that a specific temperature state in which the charger temperature is lower than the second specified value has occurred, the output of the charging current is prohibited.

  In the charger configured as described above, whether or not the charging current can be output from the charging unit to the battery pack is not determined based on the battery temperature detection value based on the battery temperature detection signal input from the battery pack. Judging by considering temperature. The charger temperature can be regarded as the ambient temperature of the charger or a temperature close to the ambient temperature.

  When the specific temperature state occurs, that is, when the battery temperature detection value is equal to or higher than the first specified value but the charger temperature is lower than the second specified value, the output of the charging current is prohibited. That is, although the battery temperature is lower than the second specified value, the battery temperature detection value is equal to or higher than the first specified value means that an abnormality has occurred in the function of detecting the battery temperature in the battery pack. There is a possibility that a battery temperature detection signal indicating a temperature higher than the actual battery temperature is output. Therefore, in such a case (when the above specific temperature relationship is established), the output of the charging current is prohibited in consideration of the fact that the actual battery temperature may be lower than the first specified value. I have to.

  Therefore, according to the charger configured as described above, even if the battery temperature detection value acquired based on the battery temperature detection signal input from the battery pack is information indicating a temperature different from the actual temperature of the battery. Thus, it is possible to perform appropriate charging control according to the actual temperature of the battery. That is, it can be suppressed that the charging current is output even though the actual battery temperature is lower than the first specified value.

  After determining that a specific temperature state has occurred and prohibiting the output of the charging current, the chargeability determination unit determines that the battery temperature detection value satisfies the specified decrease condition even if the specific temperature state continues. The output of the charging current may be permitted.

  It is presumed that as the actual temperature of the battery is higher than the charger temperature (ambient temperature), the rate of decrease in the actual temperature of the battery increases, and accordingly, the rate of decrease in the battery temperature detection value also increases. For this reason, the battery's actual temperature is higher than the ambient temperature by appropriately setting the specified decrease condition (and the battery's actual temperature is equal to or higher than the first specified value and charging current output can be permitted). Thus, it is possible to appropriately determine whether the charging current can be output.

  The specified decrease condition can be appropriately determined. For example, the battery temperature detection value may be decreased by a specified decrease amount or more. By determining the specified lowering condition in this way, it is possible to appropriately determine that the actual temperature of the battery is higher than the ambient temperature and that the output of the charging current can be permitted.

  Further, for example, the specified decrease condition may be that the difference between the battery temperature detection value and the charger temperature is decreased by a specified difference decrease amount or more. By determining the specified lowering condition in this way, it is possible to appropriately determine that the actual temperature of the battery is higher than the ambient temperature and that the output of the charging current can be permitted.

  After determining that the specific temperature state has occurred and prohibiting the output of the charging current and then continuing the specific temperature state, if the predetermined prohibition continuation condition is satisfied, Regardless of the success or failure of the specified reduction condition, the prohibition of charging current output is continued until the battery temperature detection value is equal to or higher than the first specified value and the charger temperature is equal to or higher than the second specified value. Good.

After prohibiting the output of the charging current, it may not necessarily be possible to permit the output of the charging current (the output should be prohibited) even if the specified reduction condition is satisfied.
For example, it is conceivable that the charger temperature is equal to or lower than a third specified value that is lower than the second specified value. If the charger temperature is very low (i.e. the ambient temperature is very low), even if the battery's actual temperature is below the first specified value and should not be allowed to charge, the battery temperature will be at ambient temperature. There is a possibility that it will decrease relatively rapidly and meet the specified reduction condition. In that case, charging is permitted even though the actual temperature of the battery is lower than the first specified value.

  Therefore, if a third specified value lower than the second specified value is set and the charger temperature becomes equal to or lower than the third specified value, charging is not performed even if the battery temperature detection value satisfies the specified drop condition. By doing so, it is possible to suppress charging at a low temperature when the actual temperature of the battery is lower than the first specified value.

  Also, for example, even if the specified reduction condition is not satisfied within a specified time after the output of the charging current is prohibited because it is determined that a specific temperature state has occurred, even if the specified decrease condition is subsequently satisfied However, it cannot always be said that the output of the charging current can be permitted. Because the specified drop condition is not met within the specified time, the actual temperature of the battery is very close to the charger temperature (a temperature lower than the second specified value) or lower than the charger temperature. Because it is expected.

  Therefore, if the specified decrease condition is not satisfied within the specified time, charging is not performed even if the specified decrease condition is satisfied thereafter, so that the battery is charged when the actual temperature of the battery is lower than the first specified value. This can be suppressed.

It is a perspective view which shows the external appearance of the charging system of embodiment. It is an electric circuit diagram of the battery pack of the embodiment. It is a block diagram which shows the electric constitution of the charger of embodiment. It is explanatory drawing which shows the example of a change of the battery temperature which an actual battery temperature and a charger recognize when a thermistor of a battery pack is normal. It is explanatory drawing which shows the example of a change of the battery temperature which an actual battery temperature and a charger recognize when the thermistor of a battery pack is out of order and the actual battery temperature is low (close to the charger temperature). Example of changes in actual battery temperature and battery temperature recognized by the charger when the thermistor of the battery pack is faulty and the actual battery temperature is low (however, the charger temperature is a very low temperature much lower than the actual battery temperature) It is explanatory drawing which shows. It is a part of charge process which the control part of a charger performs. It is a part of charging process (continuation of FIG. 7A) which the control part of a charger performs. It is a part of charging process (continuation of FIG. 7B) which the control part of a charger performs. It is explanatory drawing for demonstrating magnitude relations, such as various threshold values used by charge processing, and a prescribed value.

Embodiments to which the present invention is applied will be described below with reference to the drawings.
(1) Schematic Configuration of Charging System As shown in FIG. 1, the charging system according to the first embodiment includes a battery pack 1 and a charger 10. The battery pack 1 can be detachably attached to various rechargeable electric devices such as a rechargeable electric tool, a rechargeable vacuum cleaner, a rechargeable mower, and supply power to a power source (for example, a motor). It is configured to be possible. The charger 10 is configured to be able to charge a battery 30 (see FIG. 2) in the battery pack 1.

  The charger 10 is supplied with AC power from an external power source (for example, commercial AC power source) via a power cord 17, and charging power (DC voltage, DC current) for charging the battery 30 is based on the AC power. Is supplied to the battery 30 in the battery pack 1.

  A mounting portion 13 for mounting the battery pack 1 is formed on the upper surface of the charger 10. The mounting portion 13 is formed in accordance with the shape of the mounting portion 3 on the back surface of the battery pack 1 so that the battery pack 1 can be slid and attached.

  In addition, the mounting portion 13 of the charger 10 is formed with a terminal portion 15 that can be fitted to the terminal portion 5 formed on the back surface of the battery pack 1 when the battery pack 1 is mounted. The terminal part 5 of the battery pack 1 is provided with a plurality of terminals 21 to 25 (see FIG. 2) described later, and the terminal part 15 of the charger 10 is provided with a plurality of terminals 41 to 45 (see FIG. 3) described later. Is provided.

(2) Configuration of Battery Pack 1 Next, a specific configuration of the battery pack 1 will be described with reference to FIG. As shown in FIG. 2, the battery pack 1 has a positive terminal 21, a negative terminal 22, a V1 output terminal 23, and a V2 output terminal as terminals that are electrically connected to the charger 10 when the battery pack 1 is attached to the charger 10. 24 and a temperature output terminal 25 are provided. Further, the battery pack 1 accommodates a battery 30.

  For example, when the battery pack 1 is attached to the charger 10, the charging power output from the charger 10 is supplied to the battery 30 via the positive terminal 21 and the negative terminal 22 of the battery pack 1. Further, when the battery pack 1 is mounted on, for example, a rechargeable electric device, electric power for operation of the rechargeable electric device is output from the battery 30 via the positive electrode terminal 21 and the negative electrode terminal 22.

  The battery 30 has a configuration in which a plurality of chargeable / dischargeable secondary battery cells (hereinafter simply referred to as “cells”) are connected in series. Specifically, in this embodiment, the battery 30 has a configuration in which three cells of a first cell 31, a second cell 32, and a third cell 33 are connected in series.

  The positive electrode of the battery 30 (ie, the positive electrode of the third cell 33) is connected to the positive electrode terminal 21, and the negative electrode of the battery 30 (ie, the negative electrode of the first cell 31) is connected to the negative electrode terminal 22. In addition, the battery 30 of this embodiment is a lithium ion secondary battery.

  Further, the positive electrode of the first cell 31 is connected to the V1 output terminal 23 via the resistor 36, and the positive electrode of the second cell 32 is connected to the V2 output terminal 24 via the resistor 37. The V1 output terminal 23 is a terminal for outputting the first cell voltage V1, which is the voltage of the first cell 31, to the outside. The V2 output terminal 24 is a terminal for outputting the second cell voltage V2, which is the voltage of the second cell 32, to the outside.

  A thermistor 35 is provided in the battery pack 1. The thermistor 35 is provided in the vicinity of the battery 30 (for example, in the vicinity of any cell) for the purpose of detecting the temperature of the battery 30 (battery temperature). One end of the thermistor 35 is connected to the negative terminal 22, and the other end is connected to the temperature output terminal 25.

  When the battery pack 1 is attached to the charger 10, the temperature output terminal 25 of the battery pack 1 is connected to the temperature input terminal 45 (see FIG. 3) of the charger 10. In the charger 10, the temperature input terminal 45 is connected to the control unit 52 and to one end of the resistor 66. A power supply voltage Vcc having a predetermined DC voltage value is applied to the other end of the resistor 66.

  With this configuration, when the battery pack 1 is attached to the charger 10, a series circuit of the resistor 66 in the charger 10 and the thermistor 35 in the battery pack 1 is formed. A power supply voltage Vcc is applied. Then, the divided voltage value obtained by dividing the power supply voltage Vcc by the resistor 66 and the thermistor 35, that is, the voltage at both ends of the thermistor 35 is used as a signal indicating the temperature of the battery 30 (hereinafter also referred to as “battery temperature detection signal”). 1 is output from the temperature output terminal 25 and input to the controller 52 via the temperature input terminal 45 in the charger 10. The controller 52 of the charger 10 can acquire and recognize the temperature of the battery 30 based on the input battery temperature detection signal.

(3) Configuration of Charger 10 Next, a specific configuration of the charger 10 will be described with reference to FIG. The battery charger 10 has a positive terminal 41, a negative terminal 42, a V1 input terminal 43, a V2 input terminal 44, and a temperature input terminal 45 as terminals electrically connected to the battery pack 1 when the battery pack 1 is mounted. It has.

  When the battery pack 1 is attached to the charger 10, the positive terminal 41 of the charger 10 is electrically connected to the positive terminal 21 of the battery pack 1, and the negative terminal 42 of the charger 10 is connected to the negative terminal 22 of the battery pack 1. The V1 input terminal 43 of the charger 10 is electrically connected to the V1 output terminal 23 of the battery pack 1, and the V2 input terminal 44 of the charger 10 is electrically connected to the V2 output terminal 24 of the battery pack 1. The temperature input terminal 45 of the charger 10 is electrically connected to the temperature output terminal 25 of the battery pack 1.

The charger 10 also includes a switching (hereinafter abbreviated as “SW”) power supply circuit 51 and a control unit 52.
The SW power supply circuit 51 generates charging power (charging current, charging voltage) for battery charging based on AC power supplied from an external power supply via the power cord 17, and passes through the positive terminal 41 and the negative terminal 42. Supplied to the battery pack 1. Generation of charging power by the SW power supply circuit 51 is controlled by the control unit 52.

  The SW power supply circuit 51, for example, a rectifier circuit that rectifies AC power into DC, a conversion circuit that converts a DC voltage rectified by the rectifier circuit into a voltage for charging the battery 30, and a voltage that is converted by the conversion circuit is smoothed. And a smoothing circuit for generating DC charging power.

  When the battery pack 1 is attached to the charger 10, the SW power supply circuit 51 reaches the SW power supply circuit 51 through the output FET 53, the positive terminal 41, the battery pack 1, the negative terminal 42, and the current detection circuit 54. A closed circuit is formed.

  The output FET 53 is provided on this energization path in order to conduct / cut off the energization path between the SW power supply circuit 51 and the positive terminal 21. The output FET 53 may be configured using one FET, or may be configured by a combination circuit of a plurality of FETs. The output FET 53 is turned on / off by a switching signal from the charging path control circuit 55. When the output FET 53 is turned on, the energization path is conducted. When the output FET 53 is turned off, the energization path is interrupted.

  The charging path control circuit 55 outputs a switching signal in accordance with a switching control command from the control unit 52. That is, when a switching control command indicating that the output FET 53 should be turned on is input, a switching signal for turning on the output FET 53 is output, and a switching control command indicating that the output FET 53 should be turned off is input. In this case, a switching signal for turning off the output FET 53 is output.

  The current detection circuit 54 is provided on this energization path in order to detect the current flowing through the energization path between the negative terminal 42 and the SW power supply circuit 51. The current detection circuit 54 outputs a current detection signal indicating the value of the current flowing through the energization path. The current detection circuit 54 may have, for example, a configuration including a resistor provided in series with the energization path and a circuit that outputs a voltage across the resistor as a current detection signal. A current detection signal from the current detection circuit 54 is input to the control unit 52 and the current feedback circuit 58.

  The charger 10 includes a voltage monitor circuit 56 and a charger temperature monitor circuit 57. The voltage monitor circuit 56 is connected to the energization path between the output FET 53 and the positive terminal 41 and outputs a voltage detection signal indicating the voltage of this energization path. When the battery pack 1 is attached to the charger 10, the voltage monitor circuit 56 detects the voltage (battery voltage) Vb of the battery 30, and a voltage detection signal indicating the battery voltage Vb is input to the controller 52. .

  The charger temperature monitor circuit 57 directly detects the temperature of the charger 10 (hereinafter also referred to as “charger temperature”), and indirectly detects the ambient temperature of the charger 10. Is provided. The charger temperature monitor circuit 57 has a series circuit of a resistor 57a and a thermistor 57b, and a power supply voltage Vcc is applied to the series circuit. Then, the divided voltage value obtained by dividing the power supply voltage Vcc by the resistor 57a and the thermistor 57b (that is, the voltage drop of the thermistor 57b) is output as a charger temperature detection signal indicating the charger temperature, and is input to the controller 52. The

  The thermistor 57b is configured so that the temperature difference between the charger 10 and the ambient temperature of the charger 10 is within a certain level so that a charger temperature detection signal corresponding to the ambient temperature of the charger 10 is input to the controller 52. It is provided in the site. The specific installation site of the thermistor 57b is not particularly limited. For example, the thermistor 57b may be provided inside the charger 10 (inside the casing of the charger 10), or the casing of the charger 10 so that the thermistor 57b is exposed to the outside. May be provided.

  When the thermistor 57b is provided inside the charger 10, the charger temperature detected by the thermistor 57b may not match the actual ambient temperature depending on the installation site. Therefore, when the thermistor 57b is provided inside the charger 10, the difference between the charger temperature detected by the thermistor 57b and the actual ambient temperature (the temperature outside the casing of the charger 10) can be suppressed within a certain level. It is good to provide in such a part.

  In other words, as long as the thermistor 57b can appropriately detect the ambient temperature of the charger 10 (however, a difference within a certain level from the actual ambient temperature is allowed), the specific location of the charger 10 is appropriately determined. I can decide.

  The controller 52 has a plurality of functions including a function of controlling charging of the battery pack 1 attached to the charger 10. The control unit 52 includes a CPU 52a, a memory 52b, and the like. The functions of the control unit 52 are realized mainly by the CPU 52a executing various programs stored in the memory 52b.

  When the battery pack 1 is attached to the charger 10, a battery temperature detection signal is input to the control unit 52 via the temperature input terminal 45. The control unit 52 has a function of detecting that the battery pack 1 is mounted based on the battery temperature detection signal. Note that the method for determining whether or not the battery pack 1 is attached may be a method other than the method based on the battery temperature detection signal. For example, it may be determined whether or not the battery pack 1 is attached based on a voltage detection signal from the voltage monitor circuit 56.

  The control unit 52 can acquire the first cell voltage V1 from the battery pack 1 via the V1 input terminal 43 and the battery via the V2 input terminal 44 when the battery pack 1 is attached to the charger 10. The second cell voltage V2 can be obtained from the pack 1. Strictly speaking, the second cell voltage V2 is acquired based on the difference between the input voltage of the V2 input terminal 44 and the input voltage of the V1 input terminal 43. The third cell voltage V3, which is the voltage of the third cell 33, can be obtained by calculation using the battery voltage Vb detected by the voltage monitor circuit 56, the first cell voltage V1, and the second cell voltage V2. it can. In addition, you may make it acquire each cell voltage V1, V2, V3 from the battery pack 1 using another method. For example, if data communication is possible between the battery pack 1 and the charger 10, the data may be acquired by data communication.

  When the battery pack 1 is attached to the charger 10, the control unit 52 receives a battery temperature detection signal from the battery pack 1 via the temperature input terminal 45. The controller 52 can acquire and recognize the battery temperature based on the battery temperature detection signal.

  The charger 10 of the present embodiment is configured to perform the battery 30 of the battery pack 1 by a constant current constant voltage charging method (also called a CCCV (Constant Current Constant Voltage) charging method). Since the specific contents of charging by the CCCV charging method are already well known, detailed description thereof will be omitted here, and only the outline will be described for confirmation. In addition, for the sake of simplification of description, description will be given by taking a battery configured by one cell as an example.

  In the CCCV charging method, after starting charging, first, a constant charging current is supplied to the battery until the battery voltage (same as the cell voltage of one cell in this example) reaches a preset charging voltage. That is, first, CC (constant current) charging is performed. When the cell voltage reaches the charging voltage, switching from CC charging to CV (constant voltage) charging is performed, and charging is continued while adjusting the charging current so that the cell voltage is maintained at the charging voltage. Then, for example, based on the elapsed time after switching to CV charging, the value of the charging current, the rate of decrease of the charging current, etc., it is determined whether or not the charging completion condition for completing charging is satisfied. Assuming that the battery is fully charged, the charging current supply to the battery is stopped to complete the charging. If the cell voltage is already equal to or higher than the charging voltage before CC charging is started, charging is not performed.

  The battery 30 of the present embodiment is configured by connecting a plurality of cells 31, 32, and 33 in series. Therefore, in the charger 10 according to the present embodiment, the control unit 52 in the CC charging, the maximum value (hereinafter referred to as “maximum cell voltage”) among the cell voltages V1, V2, and V3 of the cells 31, 32, and 33. CC charging is continued until the charging voltage reaches a preset charging voltage. That is, the control unit 52 calculates the value of the charging current to be supplied to the battery 30 while monitoring the cell voltages V1, V2, and V3, and sends a charging control signal indicating the charging current value to the current feedback circuit 58. Output to.

  The current feedback circuit 58 receives a charge control signal from the control unit 52 and a current detection signal from the current detection circuit 54. The current feedback circuit 58 compares the actual charging current indicated by the current detection signal input from the current detection circuit 54 with the target value of the charging current indicated by the charging control signal input from the control unit 52, and performs actual charging. The SW power supply circuit 51 is controlled by outputting a control command for causing the current to match the target value to the SW power supply circuit 51. The SW power supply circuit 51 generates charging power according to the control command input from the current feedback circuit 58 and outputs it to the battery 30.

  When the maximum cell voltage reaches a preset charging voltage after the start of CC charging, the control unit 52 switches to CV charging. Specifically, based on the maximum cell voltage, the charging is continued by generating a charge control signal for continuing the charging while maintaining the maximum cell voltage at the charging voltage and outputting it to the current feedback circuit 58. Then, when a predetermined charging completion condition is satisfied, charging is completed assuming that the battery 30 is fully charged as a whole.

  Note that switching from CC charging to CV charging based on the maximum cell voltage or determining charging completion conditions is merely an example. For example, a charging voltage may be set for the battery voltage Vb, and CCCV charging may be performed based on the battery voltage Vb.

  In addition, when starting a series of charging control for charging the battery 30 based on the CCCV charging method, the control unit 52 outputs a switching control command indicating that the output FET 53 should be turned on to the charging path control circuit 55. As a result, the output FET 53 is turned on, and the energization path from the SW power supply circuit 51 to the battery 30 is made conductive.

  On the other hand, if the fully charged state is reached after the start of the charge control, the control unit 52 stops the charge and ends the charge control. Specifically, by outputting a predetermined signal for stopping or reducing the output of the charging current to the current feedback circuit 58, the output of the charging current from the SW power supply circuit 51 is stopped or reduced, and the charging path By outputting a switching control command indicating that the output FET 53 should be turned off to the control circuit 55, the output FET 53 is turned off, and the energization path from the SW power supply circuit 51 to the battery 30 is interrupted. When the charging control is finished, the control unit 52 notifies that the charging control is finished, for example, by turning on an LED of the display unit 61.

  If the maximum cell voltage is already equal to or higher than the charging voltage at the start of charging control, the charging control is terminated without performing charging. Also in this case, for example, the LED of the display unit 61 is turned on to notify the end of the charge control.

The charger 10 includes a second protect circuit 59, a DC fan 60, and a display unit 61.
Based on the voltage input from the V1 input terminal 43, the voltage input from the V2 input terminal 44, and the voltage of the positive terminal 41, the second protect circuit 59 is connected to each cell voltage V1, V2, V3 and battery voltage of the battery 30. Each voltage of Vb is monitored. When any one of the voltages satisfies a predetermined overvoltage condition, a forced-off command for forcibly turning off the output FET 53 is output to the charging path control circuit 55. The charge path control circuit 55 forcibly turns off the output FET 53 regardless of the content of the switching control command from the control unit 52 when the forced off command is input from the second protect circuit 59.

  The DC fan 60 is a fan for blowing air for cooling the inside of the battery pack 1 (mainly the battery 30), and its operation is controlled by the control unit 52. The control unit 52 operates the DC fan 60 when a predetermined fan operation condition is satisfied while the battery pack 1 is attached to the charger 10 (that is, when cooling in the battery pack 1 is necessary). To blow air to the battery pack 1.

  The display unit 61 includes a display device that can display various types of information. As the display device, for example, an LED, a liquid crystal display, and the like can be considered. In the present embodiment, the display unit 61 has at least one LED. The operation of the display unit 61 is controlled by the control unit 52.

  In addition, the charger 10 includes a power supply circuit 62. The power supply circuit 62 receives a DC voltage generated in the SW power supply circuit 51 (for example, the output of the rectifier circuit described above) and converts the input voltage into a DC power supply voltage Vcc having a predetermined voltage value (for example, 5 V). Output. The power supply voltage Vcc output from the power supply circuit 62 is used as a power supply for operation of each unit (for example, the control unit 52, the DC fan 60, etc.) in the charger 10.

(4) Overview of operation mode In the charger 10 of the present embodiment, when the battery pack 1 is mounted, the control unit 52 does not immediately start charging control based on the CCCV charging method unconditionally, Once the operation mode is set to the charging standby mode. In the charging standby mode, it is determined whether or not the charging permission condition is satisfied. Until the charging permission condition is satisfied, the charging control is not permitted (that is, prohibited) and the charging standby mode is continued. And charge control is permitted when charge permission conditions are satisfied. That is, the operation mode is shifted from the charging standby mode to the charging mode, and charging control for charging the battery 30 is started.

  In the present embodiment, as the charge permission condition, it is defined that the battery temperature is within a predetermined chargeable temperature range and the charger temperature is equal to or higher than a low temperature determination threshold value. Therefore, even if the battery temperature is within the chargeable temperature range, if the charger temperature is lower than the low temperature determination threshold, charging is not permitted and charging control is not started. However, as will be described later, even if the battery temperature is within the chargeable temperature range but the charger temperature is lower than the low temperature determination threshold, if certain conditions are met, the charge control is permitted and the charge control is performed. Is started.

In the present embodiment, a range of a predetermined lower limit temperature TL (for example, 5 ° C.) or more and a predetermined upper limit temperature TH (for example, 65 ° C.) or less is set as the chargeable temperature range.
The controller 52 of the charger 10 continues to monitor at least the battery temperature after the start of the charging control, and temporarily stops the charging control when the battery temperature is out of the chargeable temperature range. When the battery temperature falls within the chargeable temperature range, the charging control is resumed.

(5) Description of charge permission conditions Generally, when charging a battery, the temperature that needs to be monitored at the minimum is the battery temperature, and the ambient temperature does not necessarily have to be monitored.

  However, in this embodiment, not only the battery temperature but also the charger temperature is monitored, and the condition relating to the charger temperature is included as the charge permission condition. Specifically, as described above, the charging permission condition is that the battery temperature is within a predetermined chargeable temperature range and the charger temperature is equal to or higher than the low temperature determination threshold value.

  The reason is that there is a possibility that the thermistor 35 in the battery pack 1 may fail for some reason, and if it fails, the controller 52 of the charger 10 may not be able to accurately recognize the battery temperature. is there.

  As illustrated in FIG. 4, for example, when the charger temperature (that is, the ambient temperature) is about −7 ° C., for example, the battery pack 1 having a battery temperature of about 20 ° C. is attached to the charger 10. In this case, since the battery temperature is significantly higher than the ambient temperature, as shown in FIG. 4, the battery temperature decreases at a relatively large decrease rate. At this time, if the thermistor 35 of the battery pack 1 is normal, as illustrated in FIG. 4, the battery temperature (hereinafter ““ The “recognized battery temperature” is the same value as the actual battery temperature (hereinafter also referred to as “actual battery temperature”). That is, the controller 52 of the charger 10 can correctly recognize the battery temperature based on the battery temperature detection signal from the battery pack 1.

  On the other hand, when the thermistor 35 of the battery pack 1 fails and, for example, a battery temperature detection signal indicating a temperature higher than the actual battery temperature is output, the recognized battery temperature recognized by the controller 52 of the charger 10 is the actual battery temperature. The temperature is higher than the battery temperature.

  As illustrated in FIG. 5, for example, it is assumed that the battery pack 1 whose actual battery temperature is a low temperature (eg, 0 ° C.) close to the ambient temperature (eg, −7 ° C.) is attached to the charger 10. In this case, since the actual battery temperature is lower than the lower limit temperature TL (for example, 5 ° C.) of the chargeable temperature range, charging should not be permitted. However, if the thermistor 35 of the battery pack 1 is out of order and a battery temperature detection signal indicating, for example, about 20 degrees higher than the actual battery temperature is output as shown in FIG. The control unit 52 erroneously recognizes that the battery temperature is within the chargeable temperature range.

  Therefore, in this embodiment, the controller 52 of the charger 10 not only monitors the battery temperature, but also monitors the ambient temperature, and even if the battery temperature is within the chargeable temperature range, the ambient temperature is When the temperature is lower than a predetermined low temperature determination threshold value (for example, −5 ° C.), the thermistor 35 of the battery pack 1 has failed (that is, a failure in which a battery temperature detection signal indicating a temperature higher than the actual battery temperature is output). In consideration of the possibility of the occurrence of charging), charging is not permitted but prohibited.

  However, although the charging is prohibited, the control unit 52 determines whether or not the thermistor 35 of the battery pack 1 is out of order, and thus whether or not the actual battery temperature is actually lower than the lower limit temperature TL of the chargeable temperature range. .

  If the actual battery temperature is significantly higher than the ambient temperature, the actual battery temperature decreases at a relatively large decrease rate as illustrated in FIG. 4, so that the recognized battery temperature also decreases according to the decrease rate. To do. However, when the actual battery temperature is close to the ambient temperature, as illustrated in FIG. 5, the actual battery temperature is decreased little by little at a small decrease rate. For this reason, the recognized battery temperature also decreases little by little.

  Therefore, the control unit 52 determines whether or not the thermistor 35 of the battery pack 1 has failed by utilizing the characteristic that the rate of decrease in the battery temperature varies depending on the difference between the actual battery temperature and the ambient temperature as described above. to decide.

  Specifically, the control unit 52 monitors the rate of decrease in the recognized battery temperature. More specifically, after the battery pack 1 is mounted and the recognition battery temperature is first acquired, it is determined whether or not the recognition battery temperature satisfies a specified decrease condition within a specified time (for example, 10 minutes).

  The specified reduction condition can be determined as appropriate. For example, the specified reduction amount (for example, 5 degrees) or more is reduced from the recognized battery temperature (hereinafter also referred to as “initial temperature”) acquired first when the battery pack 1 is mounted. Good. Further, for example, the recognized temperature difference, which is the difference between the recognized battery temperature and the charger temperature, is lower than the recognized temperature difference when the battery pack 1 is attached and the first recognized battery temperature is acquired by a specified difference decrease amount or more. It is good also as.

  If the recognized battery temperature satisfies the specified decrease condition before the specified time elapses, the thermistor 35 determines that it is normal and the recognized battery temperature is charged even if the ambient temperature is lower than the low temperature determination threshold. As long as it is within the possible temperature range, charging is permitted.

  On the other hand, if the recognized battery temperature does not satisfy the specified decrease condition even after the specified time has elapsed, it is determined that the thermistor 35 is likely to be faulty, and the prohibition of charging is continued. In this case, thereafter, charging is not permitted unless the ambient temperature is equal to or higher than the low temperature determination threshold and the recognized battery temperature is within the chargeable temperature range.

  Thus, when the battery pack 1 is mounted, the control unit 52 of the charger 10 acquires both the recognized battery temperature and the ambient temperature, and even if the recognized battery temperature is within the chargeable temperature range, If the temperature is lower than the low temperature determination threshold, charging is temporarily prohibited. Then, after the battery pack 1 is mounted and before the specified time elapses, charging is permitted when the recognized battery temperature satisfies the specified decrease condition.

  However, even if the recognized battery temperature satisfies the specified decrease condition within the specified time, the recognized battery temperature may not necessarily indicate the actual battery temperature (that is, the thermistor 35 is normal). This is a case where the ambient temperature is in an extremely low temperature state (for example, −20 ° C. or lower) that is significantly lower than the low temperature determination threshold.

  As illustrated in FIG. 6, if the ambient temperature is in an extremely low temperature state (for example, −27 ° C. in FIG. 6), even if the actual battery temperature is lower than the lower limit temperature TL of the chargeable temperature range, When the relative temperature difference between and is large (for example, 0 ° C.), the actual battery temperature decreases at a relatively large reduction rate. Therefore, even though the actual battery temperature is lower than the lower limit temperature TL, the recognized battery temperature may satisfy the specified lowering condition within the specified time. FIG. 6 shows an example in which the battery temperature decreases from 0 ° C. or more by 5 degrees or more within 10 minutes from the installation of the battery pack 1.

  Therefore, if it is determined that the battery temperature is uniformly within the chargeable temperature range when the recognized battery temperature satisfies the specified decrease condition within the specified time, the ambient temperature becomes an ultra-low temperature state as described above. There is a risk of misrecognizing the battery temperature in the case.

  Therefore, in the present embodiment, when the control unit 52 of the charger 10 detects that the ambient temperature is in the ultra-low temperature state during the charging standby mode, the ambient temperature becomes equal to or higher than the low temperature determination threshold and is recognized thereafter. Charging is not allowed unless the battery temperature is within the rechargeable temperature range.

(6) Description of Charging Process Next, the charging process executed by the control unit 52 of the charger 10 will be described with reference to the drawings. When the controller 52 of the charger 10 detects that the battery pack 1 is attached to the charger 10, the controller 52 temporarily sets the operation mode to the charging standby mode and starts the charging process shown in FIGS. 7A to 7C. Specifically, the CPU 52a reads and executes the charging process program of FIGS. 7A to 7C stored in the memory 52b.

  Here, before explaining the specific contents of the charging process, the magnitude relationship and specific numerical examples of various threshold values and specified values used in the charging process will be described. In the charging process of the present embodiment, as shown in FIG. 8, as the various threshold values, the low temperature determination threshold value (for example, −5 ° C.), the ultra low temperature threshold value (for example −20 ° C.), and the normal temperature first threshold value (for example, 30 ° C.), a normal temperature second threshold (eg, 20 ° C.), a low temperature first threshold (eg, 0 ° C.), and a low temperature second threshold (eg, −5 ° C.). Note that the magnitude relationship between the low temperature first threshold and the low temperature second threshold and the low temperature determination threshold shown in FIG. 8 is merely an example. For example, the low temperature determination threshold value may be lower than the low temperature second threshold value.

  The ultra low temperature threshold is a threshold for determining whether or not the charger temperature (that is, the ambient temperature) is in an ultra low temperature state. The normal temperature first threshold value and the normal temperature second threshold value are threshold values for determining whether or not the DC fan 60 should be operated based on the battery temperature. The low temperature first threshold and the low temperature second threshold are thresholds for determining whether the DC fan 60 should be operated based on the charger temperature.

  7A to 7C, “battery temperature” means a recognized battery temperature unless otherwise specified. As described above, “charger temperature” means the ambient temperature of the charger 10.

  When the control unit 52 (specifically, the CPU 52a) starts the charging process by detecting the attachment of the battery pack 1, the control unit 52 acquires the battery temperature based on the battery temperature detection signal from the battery pack 1 in S110. Then, the battery temperature acquired here, that is, the battery temperature acquired when the battery pack 1 is mounted is set as the initial temperature.

  In S120, the cell temperature decrease flag is reset (OFF). In S130, the cell temperature decrease check completed flag is reset (OFF). In S140, the current battery temperature is acquired based on the battery temperature detection signal from the battery pack 1, and the current charger temperature is acquired based on the charger temperature detection signal from the charger temperature monitor circuit 57. And it transfers to the fan operation | movement determination process which has a process of S150 to S200. The fan operation determination process is a process for controlling the operation of the DC fan 60.

  When the process proceeds to the fan operation determination process, in S150, it is determined whether or not the current battery temperature (battery temperature acquired in the process of immediately preceding S140) is equal to or higher than the normal temperature first threshold value. When the current battery temperature is equal to or higher than the normal temperature first threshold (S150: YES), the process proceeds to S160.

  In S160, it is determined whether or not the current charger temperature (the charger temperature acquired in the immediately preceding processing of S140) is equal to or higher than the low temperature first threshold value. When the current charger temperature is equal to or higher than the first low temperature threshold value (S160: YES), it is considered that it is preferable to perform forced cooling by the DC fan 60 because the battery temperature is high and the charger temperature is also high. Thus, the blowing operation of the DC fan 60 is executed. After the processing of S170, the process proceeds to S210.

  In S150, if the current battery temperature is lower than the normal temperature first threshold (S150: NO), the process proceeds to S180. In S180, it is determined whether the current battery temperature is equal to or higher than the normal temperature second threshold value. When the current battery temperature is lower than the normal temperature second threshold (S180: NO), the battery temperature is low and it is considered that the forced cooling by the DC fan 60 is unnecessary, so the blowing operation of the DC fan 60 is stopped in S200. After the process of S200, the process proceeds to S210.

  In S180, when the current battery temperature is equal to or higher than the normal temperature second threshold (S180: YES), the process proceeds to S190. If it is determined in S160 that the current charger temperature is lower than the first low temperature threshold (S160: NO), the process proceeds to S190.

  In S190, it is determined whether the current charger temperature is equal to or higher than the low temperature second threshold. If it is equal to or higher than the low temperature second threshold (S190: YES), the current state of the DC fan 60 is maintained as it is, and the process proceeds to S210. If the current charger temperature is lower than the low temperature second threshold (S190: NO), the blowing operation of the fan 60 is stopped in S200. Here, one of the reasons for stopping the blowing operation of the fan 60 is a situation in which the recognized battery temperature satisfies the specified lowering condition within the specified time even though the actual battery temperature is lower than the lower limit temperature TL of the chargeable temperature range. This is to prevent this from occurring. For example, as illustrated in FIG. 5, when the fan 60 is operated in a situation where the actual battery temperature is lower than the lower limit temperature TL of the chargeable temperature range, the recognized battery temperature satisfies the specified decrease condition within the specified time (that is, There is a possibility that an affirmative determination is made in S260 described later and the cell temperature decrease flag is turned ON in S270). Therefore, when the current charger temperature is lower than the low temperature second threshold (S190: NO), the air blowing operation of the fan 60 is stopped.

  After completion of the fan operation determination process, as shown in FIG. 7B, the process proceeds to a cell temperature decrease check necessity determination process including each process from S210 to S250. The cell temperature decrease check necessity determination process is a process for determining whether or not it is necessary to shift to the cell temperature decrease check process including the processes of S260 and S270.

  When the process proceeds to the cell temperature decrease check necessity determination process, it is determined in S210 whether or not the cell temperature decrease check completed flag is set (ON). When the cell temperature decrease check completed flag is set (ON) (S210: YES), the process proceeds to the charge permission determination process including the process of S280 without shifting to the cell temperature decrease check process. When the cell temperature decrease check completed flag is reset (OFF) (S210: NO), the process proceeds to S220.

  In S220, it is determined whether or not the cell temperature decrease flag is set (ON). When the cell temperature decrease flag is set (ON) (S220: YES), the process proceeds to the charge permission determination process including the process of S280 without shifting to the cell temperature decrease check process. When the cell temperature decrease flag is reset (OFF) (S220: NO), the process proceeds to S230.

  In S230, it is determined whether the current charger temperature is equal to or higher than the ultra-low temperature threshold. When the current charger temperature is lower than the ultra-low temperature threshold, that is, when the ambient temperature is in the ultra-low temperature state (S230: NO), the cell temperature decrease checked flag is set (ON) in S250, and the process of S280 is included. Proceed to the charge permission determination process. The fact that the cell temperature decrease check completed flag is set means that the determination process in S210 is affirmed and the cell temperature decrease check process including S260 is not executed.

  In S230, when the current charger temperature is equal to or higher than the ultra-low temperature threshold, that is, when the ambient temperature is not in the ultra-low temperature state (S230: YES), the process proceeds to S240. In S240, it is determined whether or not a predetermined time has elapsed since the attachment of the battery pack 1 was detected. If the specified time or more has elapsed since the detection of battery pack 1 (S240: YES), the cell temperature decrease check completed flag is set (ON) in S250, and the process proceeds to the charge permission determination process including the process of S280. If it is determined in S240 that the specified time or more has elapsed since the detection of the attachment of the battery pack 1, the battery temperature has passed the specified time or more without satisfying the specified decrease condition. In that case, the cell temperature decrease check completed flag is set in S250, so that the cell temperature decrease check process including S260 is not executed thereafter.

  If it is determined in S240 that the specified time or more has not elapsed since the battery pack 1 is detected (S240: NO), the process proceeds to a cell temperature decrease check process having the processes of S260 and S270. The cell temperature decrease check process is a process for determining whether or not the battery temperature satisfies a specified decrease condition.

  When the process proceeds to the cell temperature decrease check process, it is determined in S260 whether or not the current battery temperature satisfies the specified decrease condition. As described above, the specified decrease condition may be, for example, a decrease from the initial temperature by a specified decrease amount (for example, 5 deg) or more, and for example, the recognition temperature difference may be decreased by a specified difference decrease amount or more. Also good.

  In S260, when the current battery temperature does not yet satisfy the specified decrease condition (S260: NO), the process proceeds to the charge permission determination process including the process of S280. When the current battery temperature satisfies the specified decrease condition (S260: YES), the cell temperature decrease flag is set (ON) in S270, and the process proceeds to the charge permission determination process including the process of S280.

  The charge permission determination process including the processes of S280 to S300 is a process for determining whether or not to permit charging of the battery 30. When the process proceeds to the charge permission determination process, it is determined in S280 whether or not the current battery temperature is within the chargeable temperature range. If the current battery temperature is not within the chargeable temperature range (S280: NO), the process returns to S140. When the current battery temperature is within the chargeable temperature range (S280: YES), the process proceeds to S290.

  In S290, it is determined whether or not the current charger temperature is equal to or higher than a low temperature determination threshold value. When the current charger temperature is equal to or higher than the low temperature determination threshold (S290: YES), charging is permitted and the process proceeds to S310. When the current charger temperature is lower than the low temperature determination threshold (S290: NO), the process proceeds to S300.

  In S300, it is determined whether or not the cell temperature decrease flag is set (ON). When the cell temperature decrease flag is reset (OFF) (S300: NO), the process returns to S140. That is, charging is temporarily prohibited and the charging standby mode is maintained. When the cell temperature decrease flag is set (ON) (S300: YES), charging is permitted and the process proceeds to S310.

  In S310, the charging control of the battery 30 by the CCCV charging method is executed. Then, when a condition for ending charging (for example, the battery 30 is charged to a fully charged state) is satisfied, the charging control is ended.

(7) Effects of the Embodiment As described above, the charger 10 according to the present embodiment determines whether or not the charge control can be performed based only on the recognized battery temperature based on the battery temperature detection signal input from the battery pack 1. Instead, the battery temperature (ambient temperature) is taken into consideration.

  Even if the recognized battery temperature is within the charge permission temperature range, if the charger temperature is lower than the low temperature determination threshold, the charge control is not permitted. This is because the recognized battery temperature is within the allowable charging temperature range even though the ambient temperature is lower than the low temperature judgment threshold because the actual battery temperature may be lower than the recognized battery temperature. is there. That is, there is a possibility that the battery temperature detection signal input from the battery pack 1 is a signal indicating a temperature higher than the actual battery temperature due to a failure of the thermistor 35 of the battery pack 1 or the like.

  Therefore, even if the recognized battery temperature is within the charging permission temperature range, if the charger temperature is lower than the low temperature determination threshold, the actual battery temperature may be lower than the lower limit temperature TL of the chargeable temperature range. In consideration of this, charging control is not permitted.

  Therefore, according to the charger 10 of this embodiment, even if the recognition battery temperature acquired based on the battery temperature detection signal input from the battery pack 1 is different from the actual battery temperature, the actual battery temperature is maintained. Appropriate charging control can be performed accordingly. That is, it is possible to prevent the charging control from being permitted even though the actual battery temperature is lower than the lower limit temperature TL of the chargeable temperature range.

  Further, in the charger 10 according to the present embodiment, when the recognized battery temperature is within the allowable charging temperature range, but the charger temperature is lower than the low temperature determination threshold, the charging control is not permitted immediately, but the battery temperature is reduced by a specified value. If the condition is met, charging is permitted. This means that the battery temperature satisfies the specified lowering condition that the actual battery temperature is sufficiently higher than the ambient temperature (here, the temperature lower than the low temperature determination threshold) (that is, the lower limit temperature TL of the chargeable temperature range or more). It is because it is guessed.

  Therefore, even if the charger temperature is lower than the low temperature determination threshold, if the battery temperature meets the specified drop condition, charging is permitted, so that charging is not permitted even though charging can actually be permitted Can be suppressed.

  However, once charging is prohibited, if the charger temperature becomes lower than the ultra-low temperature threshold or if the battery temperature has exceeded the specified time without satisfying the specified decrease condition, then the ambient temperature will be over the low temperature determination threshold. And charging is not permitted unless the recognized battery temperature is within the chargeable temperature range. By doing in this way, it can suppress that charge is performed although real battery temperature is lower than lower limit temperature TL.

  In the present embodiment, the SW power supply circuit 51 corresponds to an example of the charging unit of the present invention. The charger temperature monitor circuit 57 corresponds to an example of the charger temperature detection unit of the present invention. The control unit 52 corresponds to an example of a chargeability determination unit according to the present invention. The lower limit temperature TL in the chargeable temperature range corresponds to an example of a first specified value of the present invention. The low temperature determination threshold corresponds to an example of a second specified value of the present invention. The ultra-low temperature threshold corresponds to an example of a third specified value of the present invention.

[Other Embodiments]
As mentioned above, although embodiment of this invention was described, this invention can take a various form, without being limited to the said embodiment.

  (1) In the above embodiment, as the specified reduction condition used in the determination of S260, there are two reductions from the initial temperature, that is, a specified reduction amount (for example, 5 deg) or more, and that the recognition temperature difference is reduced by a specified difference reduction amount or more. Although an example is shown, the specified lowering condition may be a condition other than the above two examples.

  For example, the change rate of the recognized battery temperature and the change rate of the charger temperature may be in a specific relationship. In other words, as long as it can be appropriately determined that the actual battery temperature is equal to or higher than the lower limit temperature TL of the chargeable temperature range in a low temperature environment where the ambient temperature is lower than the low temperature determination threshold, the specific contents of the specified decrease condition can be determined as appropriate. .

  (2) Specific numerical values of the low temperature determination threshold, the ultra low temperature threshold, and the lower limit temperature TL can be determined as appropriate. In particular, for the low temperature determination threshold and the lower limit temperature TL, it is not always necessary to set the low temperature determination threshold to a value lower than the lower limit temperature TL, and both may be set to the same value, or the low temperature determination threshold may be set to the lower limit temperature TL. A higher value may be set. However, when setting the low temperature determination threshold to a value higher than the lower limit temperature TL, the difference between the low temperature determination threshold and the lower limit temperature TL may be as small as possible.

In addition, specific numerical values of the normal temperature first threshold, the normal temperature second threshold, the low temperature first threshold, and the low temperature second threshold can be determined as appropriate.
(3) It is not essential to use a thermistor as an element for detecting temperature. The temperature may be detected by another temperature detection method that does not use a thermistor.

  (4) The battery to be charged by the charger is not limited to a lithium ion secondary battery. The present invention can also be applied to a configuration in which a secondary battery other than the lithium ion secondary battery is charged.

  (5) Further, the functions of one component in the above embodiment may be distributed as a plurality of components, or the functions of a plurality of components may be integrated into one component. In addition, at least a part of the configuration of the above embodiment may be replaced with a known configuration having a similar function. Moreover, you may abbreviate | omit a part of structure of the said embodiment. In addition, at least a part of the configuration of the above embodiment may be added to or replaced with the configuration of the other embodiment. In addition, all the aspects included in the technical idea specified only by the wording described in the claim are embodiment of this invention.

  DESCRIPTION OF SYMBOLS 1 ... Battery pack, 3 ... Mounting part, 5 ... Terminal part, 10 ... Charger, 13 ... Mounting part, 15 ... Terminal part, 17 ... Power cord, 21, 41 ... Positive electrode terminal, 22, 42 ... Negative electrode terminal, 23 ... V1 output terminal, 24 ... V2 output terminal, 25 ... temperature output terminal, 30 ... battery, 31 ... first cell, 32 ... second cell, 33 ... third cell, 35,57b ... thermistor, 36, 37, 57a , 66 ... resistors, 43 ... V1 input terminal, 44 ... V2 input terminal, 45 ... temperature input terminal, 51 ... SW power supply circuit, 52 ... control unit, 52a ... CPU, 52b ... memory, 53 ... output FET, 54 ... current Detection circuit 55 ... Charge path control circuit 56 ... Voltage monitor circuit 57 ... Charger temperature monitor circuit 58 ... Current feedback circuit 59 ... Second protect circuit 60 ... DC fan 61 ... Display unit 62 ... Source circuit.

Claims (7)

A battery pack with a battery pack removable,
A charging unit configured to generate a charging current for charging a battery in the battery pack; and
A temperature input terminal configured to receive a battery temperature detection signal indicating the temperature of the battery from the battery pack when the battery pack is mounted;
A charger temperature detector configured to detect a charger temperature that is an internal or external temperature of the charger; and
The battery temperature detection value that is the temperature indicated by the battery temperature detection signal input to the temperature input terminal is equal to or higher than a first specified value, and the charger temperature detected by the charger temperature detection unit is the When it is determined that it is equal to or higher than a second specified value lower than the first specified value, output of the charging current from the charging unit to the battery pack is permitted, and the battery temperature detection value is the first specified value. When it is determined that a specific temperature state that is equal to or higher than the value and the charger temperature is lower than a second specified value has occurred, the charging permission determination is configured to prohibit the output of the charging current. And
Equipped with a charger. The charger according to claim 1,
The chargeability determination unit determines that the specific temperature state has occurred, and after prohibiting the output of the charging current, the battery temperature detection value is a specified decrease condition even if the specific temperature state is continuing Is configured to allow the output of the charging current,
Charger. The charger according to claim 2,
The specified decrease condition is that the battery temperature detection value is decreased by a specified decrease amount or more.
Charger. The charger according to claim 2,
The specified decrease condition is that a difference between the battery temperature detection value and the charger temperature is decreased by a specified difference decrease amount or more.
Charger. The charger according to any one of claims 2 to 4,
The chargeability determination unit determines that the specific temperature state has occurred and prohibits the output of the charging current, and then when a predetermined prohibition continuation condition is satisfied during the continuation of the specific temperature state, After the establishment, regardless of whether or not the specified reduction condition is satisfied, until the battery temperature detection value is equal to or higher than the first specified value and the charger temperature is equal to or higher than the second specified value, Configured to continue to inhibit output,
Charger. The charger according to claim 5, wherein
The prohibition continuation condition is that the charger temperature is equal to or lower than a third specified value lower than the second specified value.
Charger. The charger according to claim 5 or 6,
The prohibition continuation condition is that the specified reduction condition is not satisfied within a specified time after the output of the charging current is prohibited because it is determined that the specific temperature state occurs.
Charger.