JP6705706B2 - Battery device - Google Patents

Description

The present disclosure relates to a battery device including a rechargeable battery.

Conventionally, as a charger that charges this type of battery device, the maximum charging current that can be supplied to the battery is acquired from the battery device, and the battery is charged so that the charging current does not exceed the maximum charging current. A device configured to control is known (for example, see Patent Document 1).

JP, 9-285026, A

In the above-mentioned conventional charger, the maximum charging current is obtained by communication with the battery device, so that the charging current will not exceed the maximum charging current if the communication system with the battery device is normal. The charging control can be performed.

However, for example, if the charger side erroneously recognizes the maximum charging current due to a failure of the communication system between the charger and the battery device, the charging current to the battery cannot be suppressed to the maximum charging current or less, and the battery is It cannot be charged normally.

According to an aspect of the present disclosure, even if a communication system between a charger and a battery device fails, an abnormality in the charging current is detected on the battery device side, and the charging current can be suppressed within an appropriate range. With the goal.

A battery device according to one aspect of the present disclosure includes a battery, a charging current acquisition unit that acquires a charging current to the battery, and a control unit.
The control unit outputs a control signal for reducing the charging current when the difference between the charging current acquired by the charging current acquisition unit and the assumed charging current set based on the temperature of the battery is equal to or more than a predetermined value.

Therefore, according to the battery device of the present disclosure, when the charging current becomes larger than the assumed charging current by a predetermined value or more, the battery device can judge that fact and reduce the charging current.

For this reason, even if the communication system between the charger and the battery device fails and the charger cannot detect an abnormality in the charging current, the charging current is prevented from becoming excessive and the battery is protected from overcurrent. Can be protected.

Here, the control unit may be configured to output a control signal to the charger to reduce the charging current when the difference between the charging current and the assumed charging current is a predetermined value or more.
Further, the control unit may be configured to output, as the control signal, a stop signal for stopping the charging of the battery when the difference between the charging current and the assumed charging current is equal to or more than a predetermined value. In this case, the output destination of the stop signal may be, for example, a cutoff unit that cuts off the charge path to the battery in the battery device, or a charge control unit provided in the charger. May be.

The control unit outputs a control signal to the charger to reduce the charging current when the difference between the charging current and the assumed charging current is equal to or more than a predetermined value, and then determines whether the charging current actually decreases. If it is determined that the charging current has not dropped, a stop signal for stopping the charging of the battery may be output as the control signal.

With this configuration, when the difference between the charging current and the assumed charging current is equal to or greater than the predetermined value, the charging current to the battery can be reduced in two stages, that is, the charging current is reduced and the charging to the battery is stopped. , The battery can be protected from overcurrent.

Also, by switching the output destination of the control signal and the stop signal from the control unit, when the control signal that reduces the charging current is output to the charger, even if the control signal is not recognized by the charger side, the stop The signal can stop charging the battery.

Next, the control unit compares the charging current with a current threshold for determining whether the difference between the charging current and the assumed charging current is a predetermined value or more, and the time when the charging current exceeds the current threshold When the first threshold time is reached, a control signal is output to the charger to reduce the charging current, and when the time when the charging current exceeds the current threshold further reaches the second threshold time, the charging current is not reduced. It may be configured to output the stop signal as the control signal.

In this way, when the charging current temporarily exceeds the current threshold value due to noise or the like, it is possible to prevent the charging current from being mistakenly determined to be abnormal and the charging current from being reduced. Can be determined more appropriately and the charging current can be reduced or the charging can be stopped.

It is a perspective view showing appearance of a battery device of an embodiment. It is a block diagram showing a circuit configuration of a battery device and a charger of an embodiment. 7 is a flowchart showing an abnormality determination process executed by the control circuit of the battery device. FIG. 6 is a characteristic diagram showing a relationship between a charging current target value, an abnormal charging current detection threshold value, and a battery temperature. It is a characteristic view of the modification which changed the temperature threshold of the charging current aiming value from the characteristic view of FIG.

Embodiments of the present invention will be described below with reference to the drawings.
As shown in FIG. 1, the battery device 10 of the present embodiment is a so-called battery pack in which a battery 20 for an electric tool (for example, a lithium ion battery, see FIG. 2) is housed in a case made of synthetic resin.

In the case of the battery device 10, a charger 50 (see FIG. 2) for charging the battery 20 and a mounting portion 12 for mounting on a power tool (not shown) that operates by receiving power from the battery 20. Is provided.

Then, the mounting portion 12 is provided with a power supply terminal portion 14 and a connection terminal portion 16 for electrically connecting to the charger 50 and the electric tool.
The battery device 10 is electrically connected to the internal circuit of the power tool via the power supply terminal portion 14 and the connection terminal portion 16 provided on the mounting portion 12 by mounting the battery device 10 on the power tool via the mounting portion 12. , DC power can be supplied to the power tool.

In addition, the battery device 10 is mounted on the charger 50 (see FIG. 4) via the mounting portion 12 to electrically connect to the internal circuit of the charger 50 via the power supply terminal portion 14 and the connection terminal portion 16. Once connected, the battery 50 can be charged from the charger 50.

The power supply terminal portion 14 of the battery device 10 is provided with the positive electrode side terminal 14A, the negative electrode side terminal 14B, and the charging terminal 14C shown in FIG. 2, and the connection terminal portion 16 has four connection terminals 16A. ~16D are provided. Further, in the battery device 10, an AFE (analog front end) 22 for detecting a battery state and a control circuit 30 are provided.

The positive electrode side terminal 14A is connected to the positive electrode side terminal 20A of the battery 20 via the positive electrode side power supply line L2A, and the negative electrode side terminal 14B is connected to the negative electrode side power source line L2B to the negative electrode side terminal 20B of the battery 20. Are connected. The negative terminal 20B of the battery 20 is connected to the ground line in the battery device 10.

Then, when the battery device 10 is mounted on the electric power tool, the positive electrode side terminal 14A and the negative electrode side terminal 14B are connected to the positive electrode side terminal and the negative electrode side terminal of the electric power tool, and the battery 20 is connected to the motor and the internal circuit of the electric power tool. Supply power.

The control circuit 30 is composed of a microcomputer including a CPU 30a, a ROM 30b, and a RAM 30c. The control circuit 30 also includes a flash ROM 30d that is a non-volatile memory.

The control circuit 30 is connected to the control circuit in the electric tool via the connection terminal 16D when the battery device 10 is attached to the electric tool, and is connected to the control circuit in the electric tool (specifically, the motor). ) Communication for driving becomes possible.

The connection terminals 16A, 16B, and 16C are connected to the connection terminals on the charger 50 side when the battery device 10 is attached to the charger 50, and are open when the battery device 10 is attached to an electric tool. Becomes

Further, the charging terminal 14C is connected to the positive electrode side power supply line L2A, like the positive electrode side terminal 14A. When the battery device 10 is attached to the charger 50, the charging terminal 14C captures the charging voltage from the charger 50 with the negative electrode side terminal 14B, and connects the positive electrode side power supply line L2A and the negative electrode side power supply line L2B. It is used to supply a charging current to the battery 20 via.

The battery 20 is configured by connecting a plurality of battery cells B1, B2,... Bn in series between the positive electrode side terminal 20A and the negative electrode side terminal 20B, and a driving voltage for driving the electric tool (for example, , DC 18V or 36V) is generated.

It should be noted that the battery cells B1, B2,... Bn are each composed of, for example, a lithium ion battery that generates a DC voltage of 3.6V.
The AFE 22 detects the cell voltage of the battery cells B1, B2,... Bn forming the battery 20 in accordance with a command from the control circuit 30, and the battery 20 via the current detection resistor SR provided in the negative power supply line L2B. Is an analog circuit configured to detect a charging current to and from a discharging current from the battery 20. Then, the cell voltage and the charging/discharging current detected by the AFE 22 are input to the control circuit 30.

Further, a discharge current detection circuit 24 that detects a discharge current is connected to the current detection resistor SR, and the discharge current detection circuit 24 determines whether or not the discharge current has reached a predetermined overload determination threshold value. The overload determination circuit 26 is connected. The detection result of the discharge current detection circuit 24 and the determination result of the overload determination circuit 26 are also input to the control circuit 30.

The discharge current detection circuit 24 is for detecting the discharge current from the potential difference between both ends of the current detection resistor SR, and is composed of a differential amplifier circuit including an operational amplifier. The overload determination circuit 26 is composed of a comparator that compares the output voltage from the discharge current detection circuit 24 with a reference voltage as an overload determination threshold.

Further, the battery device 10 detects the battery voltage detection circuit 28 that detects the battery voltage VB, the thermistor 32 that detects the temperature TH1 of the battery 20, and the temperature TH2 of the substrate on which the above circuits and power supply lines are provided. A thermistor 34 is also provided. Then, the battery voltage VB, the battery temperature TH1, and the substrate temperature TH2 detected by these units are also input to the control circuit 30.

The battery voltage detection circuit 28 is configured to divide the voltage VB across the battery 20 by the resistors R2 and R3, and input the divided voltage to the control circuit 30. The thermistors 32 and 34, which are temperature detecting elements, respectively divide the power supply voltage Vcc generated by the regulator 36 in the battery device 10 between the resistors R4 and R5, and divide the divided voltage into the battery temperature. The results of detection of TH1 and substrate temperature TH2 are input to the control circuit 30.

The regulator 36 is supplied with power from the positive power supply line L2A or a charger 50 described later, and generates a power supply voltage (DC constant voltage) Vcc for driving an internal circuit.
That is, the cathodes of the diode D2 and the diode D3 are connected to the input side of the regulator 36, respectively. The anode of the diode D2 is connected to the positive power supply line L2A in the battery device 10 via the shutdown switch SW1, and the anode of the diode D3 is a connection for taking in the charger power supply voltage Vdd from the charger 50. It is connected to the terminal 16A.

The shutdown switch SW1 is turned on/off by the control circuit 30, and is turned off when connected to the charger 50 (specifically, when the power supply voltage Vdd is supplied from the charger 50). Held in a state.

Further, when the shutdown switch SW1 is in the off state, the control circuit 30 immediately switches the shutdown switch SW1 to the on state when the power supply voltage Vcc generated by the regulator 36 becomes lower than a predetermined threshold voltage.

As a result, even if the power supply voltage Vdd is not supplied from the charger 50, the battery voltage VB is supplied to the regulator 36, the power supply voltage Vcc becomes a predetermined voltage, and the control circuit 30 continues to operate.

Further, the control circuit 30 prevents over-discharge of the battery 20 when the battery device 10 is left for a long time when the shutdown switch SW1 is in the on state and the discharge of the battery 20 progresses and the battery voltage VB significantly decreases. Therefore, the shutdown switch SW1 is turned off.

When the shutdown switch SW1 is turned off in this way, the regulator 36 cannot generate the power supply voltage Vcc, and the control circuit 30 stops operating.
However, in this state, when the battery device 10 is attached to the charger 50 and the power supply voltage Vdd is supplied from the charger 50 to the connection terminal 16A, the regulator 36 uses the power supply voltage Vdd of the battery device 10. A power supply voltage Vcc for driving an internal circuit is generated.

As a result, the control circuit 30 is activated, and the charging of the battery 20 from the charger 50 is started under the control of the control circuit 30.
Further, next, in the battery device 10, a charger detection circuit 38 that detects that the battery device 10 is attached to the charger 50 from the power supply voltage Vdd input to the connection terminal 16A, and the negative power supply line L2B. A shutoff switch 40 for shutting off is provided.

The cutoff switch 40 is composed of a pair of switching elements Q2 and Q3 connected in parallel to each other by connecting the drains to each other and the sources to each other. Then, the drain is arranged on the negative electrode side terminal 14B side of the battery device 10, and the source is arranged on the negative electrode side terminal 20B side of the battery 20, thereby being provided on the negative electrode side power supply line L2B.

The switching elements Q2 and Q3 are composed of n-channel MOSFETs, and can be turned on/off at the same time by a common bias circuit 42 provided between the positive power supply line L2A and the negative power supply line L2B. Has been done.

That is, the bias circuit 42 is configured by a series circuit of the control switch SW2, the resistor R6, and the resistor R7 that are turned on/off by the signal from the control circuit 30. The control switch SW2 side end of the series circuit is connected to the positive electrode side power supply line L2A, and the resistor R7 side end is connected to the negative electrode side power supply line L2B.

The connection point between the resistors R6 and R7 is connected to the gates of the switching elements Q2 and Q3, and the resistor R7 is connected in parallel with a capacitor C1 for stabilizing the gate voltage.

Therefore, when the control switch SW2 is in the ON state and a predetermined bias voltage is applied to the gates of the switching elements Q2 and Q3, and the switching elements Q2 and Q3 are in the ON state, the negative power supply line L2B becomes conductive and the battery Charge/discharge current for 20 flows.

At this time, the charging/discharging current shunts into the two switching elements Q2 and Q3, so that the allowable currents in the switching elements Q2 and Q3 are larger than those in the case where the switching element is composed of one FET. But small ones are available. Alternatively, by using switching elements Q2 and Q3 having a large allowable current, it is possible to flow a larger current.

When the control switch SW2 is turned off and the bias voltage is not applied to the gates of the switching elements Q2 and Q3, both the switching elements Q2 and Q3 are turned off and the negative power supply line L2B is cut off. ..

The thermistor 34 that detects the substrate temperature TH2 is arranged near the switching elements Q2 and Q3 that form the cutoff switch 40.
This is because when the discharge current flowing from the battery 20 to the electric tool via the cutoff switch 40 becomes large (in other words, when the battery 20 becomes overloaded), the temperature of the cutoff switch 40 becomes high.

That is, in the present embodiment, the control circuit 30 can determine the overload state of the battery 20 based on the substrate temperature TH2 detected via the thermistor 34.
When the battery device 10 configured as described above is mounted on an electric power tool, an operation switch (trigger switch or the like) of the electric power tool is operated to form a power supply path from the battery 20 to a motor in the electric power tool. Then, a current is applied to the motor to rotate the motor.

When the motor in the electric tool is driven in this way, the control circuit 30 detects the cell voltage detected by the AFE 22, the discharge current detected by the discharge current detection circuit 24, and the thermistors 32 and 34. The battery temperature TH1 and the substrate temperature TH2 are monitored.

Then, the control circuit 30 determines whether the battery 20 is overloaded or overdischarged based on the monitoring result, and when determining the overload or overdischarged, outputs a motor stop command to the control circuit of the electric tool.

Further, when the motor stop command is output to the control circuit of the electric tool in this way, the control circuit 30 determines whether the discharge from the battery 20 has stopped, and if the discharge from the battery 20 has not stopped. The cutoff switch 40 is controlled to be in the off state.

Next, the configuration of the charger 50 will be described.
As shown in FIG. 2, the charger 50 includes an input rectifier circuit 52 for rectifying an AC voltage (for example, AC 100 V) supplied from an external power source such as a commercial power source, and a battery from DC power rectified by the input rectifier circuit 52. A charging switching power supply circuit 54 that generates a charging voltage for charging, a control circuit 56 that controls charging of the battery 20 from the charging switching power supply circuit 54, and a control circuit from the DC power rectified by the input rectification circuit 52. A power supply circuit 58 for generating a power supply voltage (DC constant voltage) Vdd for operating 56 is provided.

The control circuit 56 is composed of a microcomputer including a CPU, a ROM, and a RAM, like the control circuit 30 in the battery device 10.
When the battery device 10 is attached to the charger 50, the control circuit 56 causes the connection terminal 60B on the charger 50 side and the connection terminal 16B on the battery device 10 side, and the connection terminal 60C on the charger 50 side and the battery. It is connected to the control circuit 30 in the battery device 10 via the connection terminal 16C on the device 10 side.

Here, the connection terminals 60B and 16B are used by the control circuit 56 to acquire the target value of the charging current to the battery 20 from the control circuit 30 on the battery device 10 side. The charging current target value is an analog signal (voltage), and the control circuit 56 acquires the charging current target value from the voltage level and sets the acquired charging current target value to the charging current upper limit value (maximum). (Charging current) to control the charging of the battery 20.

The connection terminals 60C and 16C are used by the control circuit 56 to perform communication for battery charging with the control circuit 30 on the battery device 10 side. Then, when the voltage level of the connection terminal 60C becomes the low level, the control circuit 56 determines that the charging stop command is input from the battery device 10, and stops the charging of the battery 20.

Next, the charger 50 is for applying the power supply voltage Vdd generated by the power supply circuit 58 to the connection terminal 16A on the battery device 10 side when the battery device 10 is attached to the charger 50. A connection terminal 60A is provided.

The charger 50 is also provided with a positive electrode side charging terminal 50A and a negative electrode side charging terminal 50B. When the battery device 10 is attached to the charger 50, the positive electrode side charging terminal 50A is connected to the charging terminal 14C of the battery device 10, and the negative electrode side charging terminal 50B is connected to the negative electrode side terminal 14B of the battery device 10. Connected.

In addition, the positive electrode side charging terminal 50A is connected to the output line of the charging voltage from the charging switching power supply circuit 54 to supply the charging voltage to the charging terminal 14C of the battery device 10 (then, the positive electrode side terminal 20A of the battery 20). ). Further, the negative electrode side charging terminal 50B is connected to the ground line common to the charging switching power supply circuit 54.

As a result, the charging current is supplied to the battery 20 in the battery device 10 from the charging switching power supply circuit 54 via the positive charging terminal 50A and the negative charging terminal 50B.

The control circuit 56 monitors the state of charge of the battery 20 by communicating with the control circuit 30 in the battery device 10, and switches the charging switching power supply circuit 54 to the battery 20 until the battery 20 is fully charged. Control charging.

Next, when the battery device 10 is attached to the charger 50 and the fact is detected by the charger detection circuit 38, an abnormality executed by the control circuit 30 (more specifically, the CPU 30a) of the battery device 10 is performed. The determination process will be described.

This abnormality determination processing determines whether or not the charging current supplied from the charger 50 to the battery 20 is normal when the battery device 10 is attached to the charger 50 to determine whether the charging current is abnormal. If determined, it is a process for reducing the charging current for the charger 50.

As shown in FIG. 3, in the abnormality determination process, first, in S110 (S represents a step), the current decrease flag is set to the off state, and in subsequent S120, the battery temperature TH1 is acquired via the thermistor 32. ..

Next, in S130, the charging current target value as the assumed charging current is determined based on the battery temperature acquired in S120. The target charging current value is used as the upper limit value (maximum charging current) of the charging current on the charger 50 side, and is set according to the battery temperature based on the map shown in FIG.

That is, a chargeable region called an operating region is set in the battery 20, and the operating region of the charging current is, for example, 3A in the temperature range of 0°C to 10°C and 6A in the temperature range of 10°C to 60°C. , And so on, the current value is set according to the temperature.

Then, the map for setting the charging current target value is set so that the charging current target value is a current value that is about 1 A lower than the Operating Region. In S130, the charging current target value is set to the charging current target value. decide.

Next, in S140, as shown in FIG. 4, a current value larger than the charging current target value determined in S130 by a predetermined value (2A in the figure) is set as the abnormal charging current detection threshold value.
This abnormal charging current detection threshold is a current threshold for detecting an abnormality of the charging current on the battery device 10 side, and in the present embodiment, the charging current target value and the charging current target value are set for each temperature range defined by the Operating Region. It is set to a value larger than Operating Region.

Next, in step S150, the charging current target value determined in step S130 is output to the charger 50 via the connection terminal 16B for bidirectional communication, so that the charging current with respect to the charger 50 becomes the charging current target value. The battery 20 is charged within a range that does not exceed.

Then, in the subsequent S160, the charging current currently being supplied to the battery 20 is acquired via the AFE 22, and in S170, the charging current is the abnormal charging current detection threshold value set in S140 (hereinafter, simply the current threshold value). It is determined whether or not the above has been exceeded.

If it is determined in S170 that the charging current value does not exceed the current threshold value, the charging current is normal, and the process proceeds to S240.
Then, in S240, it is determined whether or not the condition for completing the charging of the battery 20 is satisfied. If the condition for completing the charging is satisfied, the charging of the battery 20 is completed, so the abnormality determination process is ended. If the charging completion condition is not satisfied, the process proceeds to 120 again.

The determination process in S240 is performed based on, for example, the charging completion signal input from the charger 50 via the connection terminal 16C.
On the other hand, in S170, when it is determined that the charging current value exceeds the current threshold value, the process proceeds to S180, and the abnormal charging current detection time is integrated by counting up the time counter, for example, The process proceeds to S190.

In S190, it is determined whether or not the current reduction flag is in the ON state. If the current reduction flag is not in the ON state, the process proceeds to S200, and the accumulated time of the abnormal charging current detection time accumulated in S180 is set in advance. It is determined whether it is equal to or more than the set first threshold value.

When it is determined in S200 that the integrated time is not greater than or equal to the first threshold, the process proceeds to S240, and when it is determined in S200 that the integrated time is greater than or equal to the first threshold, the process proceeds to S210. To do.

Then, in S210, the charging current target value is reduced by a predetermined correction value in order to reduce the charging current to the battery 20, and in subsequent S220, the charging current target value after the reduction (in other words, after the correction). Is output to the charger 50 via the connection terminal 16B. As a result, on the charger 50 side, the upper limit value of the charging current (maximum charging current) decreases, and the charging current flowing in the battery 20 is suppressed.

In S220, when the corrected charging current target value is output to the charger 50, the current reduction flag is turned on in S230, and the process proceeds to S240.
Next, when it is determined in S190 that the current reduction flag is in the ON state, that is, after the charging current target value is reduced in S210, it is determined that the charging current value is larger than the current threshold value in S170. If so, the process proceeds to S250.

Then, in S250, it is determined whether the integrated time of the abnormal charging current detection time updated in S180 is equal to or more than the second threshold value. The second threshold value is larger than the first threshold value, and the difference from the first threshold value is that the charging current target value is reduced in S210 and then the charging current value is reduced to the current threshold value by the charging control on the charger 50 side. It is the time required to determine whether or not.

Then, in S250, when it is determined that the integrated time is less than the second threshold value, the process proceeds to S240, and when it is determined that the integrated time is equal to or more than the second threshold value in S250, the process proceeds to S260. After stopping the charging by the charger 50, the abnormality determination process is ended.

In S260, the connection terminal 16C is set to the low level to output a charge stop command to the charger 50 and stop the charging by the charger 50.
This is because when a charging stop command is output via the connection terminal 16B, when there is an abnormality in the communication system between the battery device 10 and the charger 50 configured using the connection terminal 16B, This is because the charging of the battery 20 cannot be stopped.

That is, in the present embodiment, the route for outputting the charging current target value from the battery device 10 to the charger 50 and the route for the command signal that causes the charger 50 to stop charging the battery 20 are made different routes. The charging current can be surely reduced when the charging current is abnormal.

As described above, in the battery device 10 of the present embodiment, when the battery device 10 is attached to the charger 50, the control circuit 30 monitors the charging current supplied from the charger 50 to the battery 20. ..

Then, the control circuit 30 limits the upper limit of the charging current on the charger 50 side when the charging current value exceeds the current threshold value for detecting abnormal charging and the accumulated time reaches a predetermined time defined by the first threshold value. The charging current target value used for charging is reduced by a predetermined value.

As a result, if the output path of the charging current target value is normal and the charger 50 is operating normally, the charging current from the charger 50 to the battery 20 will decrease, and the charging current value will be below the current threshold value. Will be able to be limited to.

Even if the charging current target value is decreased, if the charging current value exceeds the current threshold value, the elapsed time thereafter is the predetermined time defined by the second threshold value (specifically, the second threshold value-the second threshold value). It is determined whether or not the time has reached 1). Then, when the elapsed time thereafter reaches the predetermined time defined by the second threshold value, the charger 50 is caused to stop charging the battery 20.

Therefore, according to the battery device 10 of the present embodiment, the charging current can be monitored on the battery device 10 side and the charging current can be limited to the current threshold value or less. Therefore, even if the communication system between the charger 50 and the battery device 10 fails and the charger 50 cannot detect the abnormality in the charging current, the charging current is prevented from becoming excessively large, and the battery 20 is prevented. Can be protected from overcurrent.

Further, when the charging current value exceeds the current threshold value, the control circuit 30 controls the charger 50 to reduce the charging current by decreasing the charging current target value, and by this control, the charging current value reaches the current threshold value. If it does not decrease, the charging of the battery 20 by the charger 50 is stopped.

Therefore, when an abnormality of the charging current is detected, the battery can be protected from the overcurrent in two stages, that is, the charging current is reduced and the charging of the battery 20 is stopped. Can be better suppressed.

Further, when the abnormality of the charging current is detected, the charging of the battery 20 is not immediately stopped. Therefore, if the charging current can be reduced by the control of the charger 50, the battery 20 of the charger 50 can be reduced. The battery 20 can be fully charged by continuing to charge the battery.

In the present embodiment, the AFE 22 that detects the charging current to the battery 20 via the current detection resistor SR corresponds to the charging current acquisition unit of the present disclosure, and the control circuit 30 that executes the above-described abnormality determination process. Corresponds to the control unit of the present disclosure.

Although one embodiment of the present disclosure has been described above, the present disclosure is not limited to the above embodiment, and various aspects can be adopted without departing from the scope of the present disclosure.
For example, in the above-described embodiment, the control circuit 30 has been described as detecting the discharging current from the battery 24 via the operational amplifier 24 and detecting the charging current to the battery 24 via the AFE 22. The charging current may be detected via the operational amplifier 24.

The charging current to the battery 20 may be acquired from the charger 50. With this configuration, even when the battery device 10 does not include the current detection resistor SR or the AFE 22, the same abnormality determination process as that of the above-described embodiment is performed to protect the battery 20 from overcurrent during charging. can do.

Further, in the above-described embodiment, when the charging of the battery 20 by the charger 50 is stopped, the stop signal is output to the charger 50 by setting the connection terminal 16C to the low level.

On the other hand, by outputting a stop signal to the control switch SW2, the control switch SW2 is turned off, and the cutoff switch 40 as a cutoff unit provided on the negative power supply line L2B is turned off. You may make it cut off the charging path to.

By doing so, it becomes possible to stop the charging of the battery 20 by the charger 50 in the battery device 10 without outputting the charging stop signal to the charger 50, and the charging of the battery 20 can be performed. It can be stopped more reliably.

Next, in the above-described embodiment, the charging current target value as the assumed charging current is set for each temperature region corresponding to the temperature range of the operating region, which is the chargeable region of the battery 20, and the charging current target value is set to a predetermined value. The value obtained by adding is used as the current threshold value to determine the charging current abnormality.

On the other hand, as shown in FIG. 5, the temperature range of the charging current target value may be shifted from the temperature range of the Operating Region.
That is, since the target value of the charging current is the upper limit command value of the charging current for the charger 50, it is preferable to stabilize the charging current so that it does not change frequently in response to changes in the battery temperature.

Then, for this purpose, the temperature range of the charging current target value is made narrower than the temperature range of the Operating Region, and in S130, when the temperature threshold which is the boundary of the temperature range is increased for a certain time or more (or is decreased). It is conceivable to update the target value of the charging current.

Further, when the charging current target value is updated in this way, the current threshold value (abnormal charging current detection threshold value) may be a value obtained by adding a predetermined value to the charging current target value. However, this makes it difficult for the current threshold value to change with changes in the battery temperature.

Therefore, as shown in FIG. 5, the temperature range of the current threshold is made to coincide with the temperature range of the Operating Region, and in S140, the current threshold is set based on the latest battery temperature according to the characteristics shown in FIG. May be.

Then, in this way, it is possible to carry out the abnormality determination of the charging current using the current threshold value without a response delay, and it is possible to suppress the erroneous determination of the abnormality of the charging current.
Next, in the above-described embodiment, the battery device 10 has been described as being mounted and used on an electric power tool, but the battery device of the present disclosure is mounted and used on an electric device different from the electric power tool. Or may be built into various electric devices.

Further, the battery device 10 of the present disclosure does not necessarily have to be configured separately from an electric device such as an electric power tool, and may be built in the electric device such as an electric power tool.
Further, a plurality of functions of one constituent element in the above-described embodiment may be realized by a plurality of constituent elements, or one function of one constituent element may be realized by a plurality of constituent elements. Further, a plurality of functions of a plurality of constituent elements may be realized by one constituent element, or one function realized by a plurality of constituent elements may be realized by one constituent element. Further, a part of the configuration of the above embodiment may be omitted. Further, at least a part of the configuration of the above embodiment may be added or replaced with respect to the configuration of the other above embodiment. It should be noted that all modes included in the technical idea specified only by the wording recited in the claims are the embodiments of the present invention.

10... Battery device, 12... Mounting part, 14... Power supply terminal part, 14A... Positive side terminal, 14B... Negative side terminal, 14C... Charging terminal, 16... Connection terminal part, 16A-16D... Connection terminal, 20... Battery , 20A... Positive side terminal, 20B... Negative side terminal, 22... AFE (analog front end), L2A... Positive side power supply line, L2B... Negative side power supply line, SR... Current detection resistor, 24... Discharge current detection Circuit, 26... Overload determination circuit, 28... Battery voltage detection circuit, 30... Control circuit, 32, 34... Thermistor, 36... Regulator, 38... Charger detection circuit, 40... Break switch, 42... Bias circuit, SW1... Shutdown switch, SW2... Control switch, 50... Charger, 50A... Positive side charging terminal, 50B... Negative side charging terminal, 52... Input rectifying circuit, 54... Charging switching power supply circuit, 56... Control circuit, 58... Power supply circuit , 60A to 60C... Connection terminals.

Claims (2)

A battery,
A charging current acquisition unit that acquires a charging current supplied from the charger to the battery,
When the charging current acquired by the charging current acquisition unit is larger than the assumed charging current set based on the temperature of the battery by a predetermined value or more, a control signal for reducing the charging current is output to the charger. Then, the charging current is reduced, and then it is determined whether or not the charging current is actually reduced. If the charging current is not reduced, a stop signal for stopping the charging of the battery is output. A control unit configured to
A battery device including. The control unit compares the charging current with a current threshold for determining whether the charging current is greater than a predetermined value by more than the assumed charging current , and the charging current exceeds the current threshold. When the time reaches the first threshold time, reduces the charging current by outputting the control signal to the charger, then further, the time during which the charge current exceeds the current threshold value reaches a second threshold time The battery device according to claim 1, wherein the battery device is configured to output the stop signal when it is determined that the charging current has not dropped.