JP2002374634A - Charging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a charging device which can improve handleability, when a refresh discharging carried out. SOLUTION: When it is decided that a refresh discharging of a battery is necessary (S14: Yes), refresh discharging carried out before charging start (S16). When the refresh discharging of the battery is carried out, the battery is charged quickly and the charging is finished faster than charging without refreshing out (S38-S52). Therefore, a user can charge a battery, without worring about the unfinish of refreshing, so that the handleability of the charging device is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charging device for charging a secondary battery, and more particularly to a charging device capable of performing a refresh discharge.

[0002]

2. Description of the Related Art In a secondary battery such as a nickel cadmium battery or a nickel hydride battery, if charging and discharging are repeated in a state where the capacity is not sufficiently used, the charging capacity is reduced due to a memory effect. In order to cope with this memory effect, a charging device provided with a refresh circuit that uses up the capacity of a secondary battery by operating a switch has been provided.

Further, in Japanese Patent Application Laid-Open Nos. Hei 6-269131 and Hei 7-143680, the necessity of refresh discharge is determined, and refresh discharge is automatically performed before charging to prevent the memory effect from occurring. The technology is disclosed.

[0004]

However, if the refresh discharge is automatically started before the charge, the battery is used in a case where the battery is charged without performing the refresh discharge and a case where the battery is charged after the refresh discharge is performed. Since the time until the battery becomes possible varies greatly, the battery charging time management becomes complicated when the battery is replaced at regular intervals, such as in a factory, and the usability of the charging device becomes poor. appear.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem, and an object of the present invention is to provide a charging device that can improve the usability in performing a refresh discharge.

[0006]

In order to achieve the above object, a first aspect of the present invention is a refresh discharge section (21) for performing a refresh discharge of a battery, and a charging section (2) for charging a battery.
2), wherein the charging unit (22)
However, when the battery is refresh-discharged (S14:
Yes), the charging is completed in a shorter time than when the rapid charging is performed and the refresh discharge is not performed (S38 to S5).
0) is a technical feature.

According to the first aspect, when the refresh discharge of the battery is performed, the charge is completed in a shorter time than when the refresh discharge is not performed. For this reason,
Even if the refresh discharge is performed, the time required for the refresh discharge and the charge can be shortened, and the time until the battery can be reused can be shortened.

[0008] A second aspect of the present invention is a charging apparatus including a refresh discharge unit (21) for performing a refresh discharge of a battery and a charging unit (22) for charging a battery, and determines whether or not a refresh discharge of the battery is necessary. The refresh discharge unit determines that the refresh discharge is necessary (S14: Yes).
Refresh discharge is performed before the start of charging (S16). When the charging unit performs refresh discharge of the battery,
The technical feature is that the charging is completed in a shorter time than in the case where the rapid charging is performed and the refresh discharge is not performed (S38 to S50).

According to a second aspect of the present invention, it is determined whether or not the battery requires a refresh discharge, and when it is determined that the refresh discharge is required, the refresh discharge is performed before the charging is started. Then, when the battery is refresh-discharged, the charge is completed in a shorter time than when quick refresh is performed and refresh discharge is not performed. For this reason, even if the refresh discharge is automatically performed, the time required for the refresh discharge and charging is shortened, so that the battery can be reused between when the refresh discharge is performed and when the refresh discharge is not performed. The difference in the waiting time until it becomes possible can be reduced.

A third aspect of the present invention is a charging apparatus including a refresh discharging section (21) for performing a refresh discharge of a battery and a charging section (22) for charging a battery, and determines whether or not a refresh discharge of the battery is necessary. (S1)
4) When the refresh discharger determines that the refresh discharge is required by the determination unit (S14: Yes),
Refresh discharge is performed before the start of charging (S16). When the charging unit performs refresh discharge of the battery,
The charging is completed in a shorter time than in the case where the quick charge is performed and the refresh discharge is not performed, and the sum of the refresh discharge time and the charge time is made substantially the same as the charge time when the refresh discharge is not performed (S38 to S50). ) Is a technical feature.

According to a third aspect of the present invention, it is determined whether or not the battery needs to be refresh-discharged. When it is determined that the refresh-discharge is required, the refresh-discharge is performed before the start of charging. Then, when the battery is refresh-discharged, the charging is completed in a shorter time than in the case where the quick charge is performed and the refresh discharge is not performed, and the total of the refresh discharge time and the charge time is calculated when the refresh discharge is not performed. And the charging time is almost the same. For this reason, even if the refresh discharge is automatically performed and the refresh discharge is not performed, the standby time until charging is completed and the battery can be reused is the same. Battery can be charged without being aware of the presence or absence of discharge,
The usability of the charging device that performs refresh discharge can be improved. In addition, when the refresh discharge is not performed, the charge is performed in the same time as when the refresh discharge and the rapid charge are performed, so that the charge can be performed over a long time, and the battery life can be extended.

According to the fourth aspect, the necessity of the refresh discharge is determined based on the charging history of the storage unit provided in the battery, so that the necessity of the refresh can be accurately determined.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a charging device and the like according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a state where the battery pack 50 is loaded in the charging device 10. FIG. 2 shows the appearance of the charging device 10. FIG. 3 shows an appearance of the battery pack 50, and FIG. 4 shows a battery drill 70 driven by the battery pack 50.

First, the configuration of the battery pack 50 will be described with reference to FIG. The battery pack 50 has a plurality of nickel-metal hydride batteries 58 which are electrically connected in series as shown in FIG. 1 in a resin casing 51 formed in a substantially prismatic shape. A temperature sensor TM for detection and an EEPROM 61 constituting a storage unit for storing information on the type of the battery pack and the charging history are provided.
The temperature sensor TM is composed of a thermistor whose electric resistance changes with temperature.

As shown in FIG. 3, on the upper end side of the casing 51 of the battery pack 50, a battery drill 70 and a charging device 1 are provided.
A fitting portion 52 having a fitting groove 53 that can be fitted to the mating side when the fitting portion 52 is mounted is provided in parallel in a rail shape. Is provided with a hook 54 that can enter and exit the device. This hook 5
4 is formed integrally with a lever 55 provided on the side surface of the casing 51, and is urged in a projecting direction by a coil spring (not shown). Therefore, when the battery pack 50 is mounted on the battery drill 70 or the charging device 10, the battery pack 50 can be engaged with a predetermined hook groove formed therein.

Thus, the battery drill 70 and the charging device 1
It serves to prevent the battery pack 50 from easily coming off from zero. Further, the lever 5 is pressed against the urging force of the coil spring.
When the battery pack 5 is pushed down toward the lower end of the casing 51, the hook 54 also moves toward the lower end so as to retract, so that engagement with the hook groove is released, and the battery pack 50 can be removed from the battery drill 70 or the charging device 10. Will be possible.

A vent 56 is provided at the upper end of the casing 51 so as to be sandwiched by the fitting portion 52.
A positive terminal groove 57, a negative terminal groove 59, and a connector 60 are provided. The ventilation port 56 is formed at a position where it can communicate with the ventilation port 16 provided in the charging device 10 when the battery pack 50 is mounted on the charging device 10. Thereby, air can be sent into the battery pack 50 by the cooling fan 23 built in the charging device 10, so that the battery pack 50 being charged can be cooled. That is,
An air cooling system using the charging device 10 is constructed.

On the other hand, a positive terminal and a negative terminal (not shown) are provided in the positive terminal groove 57 and the negative terminal groove 59, respectively.
When the battery pack 50 is mounted on the battery pack 0, these terminals can be brought into contact with the power receiving terminal and the output terminal on the other side. A terminal for connecting the temperature sensor TM and the EEPROM 61 shown in FIG. 1 is provided inside the connector 60.

The battery pack 50 constructed as described above
Is used by being mounted on a battery drill 70 as shown in FIG. In the battery drill 70, a battery pack mounting portion 75 is formed below a grip portion 74 that can be gripped by a user. Since the battery pack mounting portion 75 is formed with a fitting portion that can be engaged with the fitting portion 52 of the battery pack 50 and a predetermined hook groove with which the hook 54 of the battery pack 50 can be engaged. The battery pack 50 is detachably attached to the battery pack mounting portion 75.

In the battery drill 70 in which the battery pack 50 is mounted as described above, since the plus terminal and the minus terminal of the battery pack 50 are connected to the respective power receiving terminals on the battery drill 70 side, power is supplied from both terminals. Can be received. Thus, the chuck 76 can be rotated by the motor (not shown).

Next, the configuration of the charging device 10 for charging the battery pack 50 will be described with reference to FIGS. As shown in FIG. 2, the charging device 10 has a housing 11 made of resin, and the housing 11 has a fitting portion 12 to which the battery pack 50 can be mounted, and a battery pack 50 by a built-in cooling fan.
An intake port 13 and the like capable of inhaling the air to be sent in from the outside are integrally formed. Further, the housing 11 of the charging device 10 is provided with various indicators (not shown) such as a capacity display lamp for displaying the capacity of the battery pack 50 being charged and a status display lamp for indicating the operation status of the charging device 10. These are controlled for lighting by a control circuit described later.

The fitting portion 12 is formed with a guide 14 that can guide the fitting groove 53 of the battery pack 50 and an air outlet 16 that can communicate with a vent 56 of the battery pack 50. Is also provided with a predetermined hook groove in which the hook 54 of the battery pack 50 can be engaged. The fitting portion 12 is provided with an output terminal that can be electrically connected to the plus terminal and the minus terminal of the battery pack 50, and a connector (not shown) that can be connected to the connector 60 of the battery pack 50. Is provided. Thus, the control circuit in charging device 10 can obtain predetermined temperature information and the like from battery pack 50 via this connector.

As shown in FIG. 1, the control circuit of the charging device 10 mainly includes a power supply circuit 22, a charging current control unit 24, a control unit 26, a voltage detection unit 27, a temperature detection unit 28, and a storage unit 2.
9, a fan 23, a discharge load 21, a charge / discharge switching unit 25, and the like. The power supply circuit 22 is set to have a capacity capable of charging the battery 58 of the battery pack 50.
The charge / discharge switching unit 25 applies the voltage from the power supply circuit to the battery 58 of the battery pack 50 at the time of charging, and flows the power of the battery 58 to the discharge load 21 at the time of refresh discharge. The temperature detection unit 28 is configured to be able to detect the temperature of the battery being charged by the temperature sensor TM.
Is configured to detect a battery voltage. On the other hand, the storage unit 29 stores current value control information such as a predetermined map. The fan 23 is connected to the intake port 1 shown in FIG.
The air taken in from the outside through the air inlet 3 is sent to the vent 56 of the battery pack 50 through the air vent 16 (see FIG. 3), and the battery 58 in the battery pack 50 is forcibly air-cooled.

The control section 26 differentiates the temperature value output from the temperature detection section 28 to obtain a temperature rise value, and then calculates a predetermined current value based on the current value control information in the storage section 29. The charging current control unit 24 uses the current value as a current command value.
It is configured to be able to output to The charging current control unit 24 is also configured to control the power supply circuit 22 based on the current command value from the control unit 26 and adjust the charging current of the battery pack 50.

Next, the operation principle of the charging device according to the first embodiment will be described. As for the battery, when the charging current is increased, the charging time is shortened, but the temperature rise is increased. Conversely, when the charging current is reduced, the charging time is prolonged, but the temperature rise is reduced. In particular, nickel-metal hydride batteries
It has the characteristic that the temperature gradient (temperature rise value) greatly changes depending on the charging current and the capacity already charged. For this reason, in this embodiment, charging is performed while changing the current value in order to suppress a rise in temperature. That is, while the charging device according to the related art performs charging at a constant current value, the charging device according to the present embodiment determines the state of the battery based on the temperature rise value, and determines the temperature rise of the battery. Charging is performed while changing the current value in accordance with the current that can be made to flow while keeping the temperature constant, that is, the temperature rise of the battery.

Here, when the temperature rise is high, a relatively small charging current is passed, and when the temperature rise is low, a relatively large charging current is passed.

The operating principle of the charging device according to the first embodiment will be described in more detail with reference to FIG. FIG. 5 shows the battery temperature rise value on the vertical axis and the charging time on the horizontal axis,
A curve L in the figure shows a temperature rise value at the time of completion of charging corresponding to the charging time when charging is performed so that the temperature rise value becomes constant. For example, if the battery temperature started at 20 ° C. is 43
° C (temperature rise value 23 deg), the charging time was 60 minutes and the battery temperature was 60 minutes.
When the current was controlled to reach a temperature of 40 ° C. (temperature rise value of 40 deg), the charging time was 30 minutes, and the battery temperature was 78 ° C.
It shows that the charging time is 20 minutes when the current is controlled so as to reach ° C. (temperature rise value 58 deg).

That is, based on the curve L, the temperature rise value (gradient) is calculated from the charge completion time and the battery temperature rise value at the time of charge completion.
Can be requested. For example, in order to complete the charging at a temperature rise of 23 deg, it is understood that the charging should be performed so as to have a temperature gradient (temperature rise value) indicated by a straight line a connecting 0 deg in the figure and 23 deg on the curve L. In this case, the charging is completed when the temperature reaches 43 ° C. (temperature rise value 23 deg) almost exactly in 60 minutes.

On the other hand, when charging is completed with a temperature rise of 23 deg when the outside air temperature and the battery temperature are 10 ° C., a temperature gradient (temperature rise) shown by a solid line a connecting 0 deg and 23 deg on the curve L in FIG. Value). Also in this case, charging is completed at a temperature of 33 ° C. (temperature rise value 23 deg) in exactly 60 minutes.

Similarly, when charging is completed at a temperature rise of 23 deg when the outside air temperature and the battery temperature are 30 ° C., a temperature gradient (temperature rise) indicated by a solid line a connecting 0 deg and 23 deg on the curve L in FIG. Value). Also in this case, charging is completed at a temperature of 53 ° C. (temperature rise value 23 deg) in exactly 60 minutes.

The charging device of the first embodiment completes charging in a fixed time of one hour when refresh discharge is not performed. For example, when the battery temperature and the outside air temperature are 20 ° C., charging is performed so that the battery temperature becomes 43 ° C. (temperature rise value 23 deg).

On the other hand, when performing the refresh discharge, the charge time is adjusted so that the total time of the refresh discharge and the charge is one hour. For example, if the refresh discharge takes 30 minutes, the charge is completed in 30 minutes. Here, from the charging time of 30 minutes, 40 deg is determined as the temperature rise value as shown in FIG.
Charging is performed so as to have a temperature gradient (temperature rise value) indicated by a solid line b connecting deg and 40 deg on the curve L. In this case, charging is completed at a temperature of 60 ° C. (temperature rise value of 40 deg) in approximately 30 minutes. Therefore, even when the battery is charged after performing the refresh discharge, the charging is completed in one hour from the loading of the battery pack into the charging device.

Here, when the battery temperature and the outside air temperature are different, the curve L in FIG. 5 shifts according to the outside air temperature. That is, when the battery temperature is 15 ° C. and the outside air temperature is 10 ° C., the curve L shifts downward by 5 deg. Conversely, when the battery temperature is 10 ° C. and the outside air temperature is 15 ° C., the curve L shifts upward by 5 deg. In the present embodiment, when the battery temperature is different from the outside air temperature, the temperature gradient is obtained from the charging time as described above using the curve L shifted by the difference.

Next, refresh discharge and charging by the charging device according to the first embodiment will be described with reference to the flowcharts of FIGS. First, the control unit 36 controls the EEPROM 61 of the battery pack 50.
Is read out (S12), and it is determined whether refresh discharge is necessary (S14). In the present embodiment, refresh discharge is performed once every time charging is repeated five times, and it is determined whether only charging was performed four times since the previous refresh discharge.

Here, when it is not necessary to perform the refresh discharge (S14: No), the process proceeds to the part A shown in FIG. 7 and the charging is started immediately. On the other hand, if only the charge is repeated four times since the previous refresh discharge, and it is necessary to perform the refresh discharge at the time of this charge (S1
4: Yes), the charge / discharge switching unit 25 (see FIG. 1) is controlled to apply the electric power of the battery 58 to the discharge load 21 side to start the refresh discharge (S16). Then, the voltage of the battery 58 is detected via the voltage detection unit 27, and it is determined whether the refresh discharge has ended based on whether the voltage has dropped below a predetermined value (S18). Until the refresh discharge ends (S18: No), the process returns to S16 to continue the discharge. When the refresh discharge ends (S18: Ye)
s) Then, the process proceeds to a portion B shown in FIG. 7 and charging is started.

The description of the charging process will be continued with reference to FIG. Here, first, the case where the refresh discharge is not performed will be described (S14: No). The temperature of the battery pack 50 is detected via the temperature detector 38 (S32). Here, it is assumed that the outside air temperature and the battery temperature are 20 ° C. Since the refresh discharge is not performed, one hour is set as the charging time (S34), and the storage unit 39 holding the value of the curve L described above with reference to FIG. Once determined, the temperature gradient is calculated (S40). Here, the temperature 0 deg shown in FIG.
The gradient of a straight line a connecting the curve 23 and 23 deg on the curve L is determined.

The control unit 36 obtains a temperature rise value by differentiating the difference between the previous temperature value input from the temperature detection unit and the currently input temperature value (S42), and calculates the detected temperature rise value in S40. The current value is determined by comparing with the gradient calculated in (S44). Here, when the temperature rise value is lower than the gradient, the current value is increased from the current value, and when it is low, the current value is decreased.

Next, it is determined whether the current value is equal to or less than a predetermined value (S46). That is, when the charging is completed, the charging current sharply decreases. Therefore, when the current value becomes equal to or less than the predetermined value, it is determined that the charging is completed. When the charging current falls below a predetermined value (S46:
Yes), after writing the charging history in the EEPROM of the battery pack 50 (S52), the charging process is completed. On the other hand,
When the current is equal to or more than the predetermined value (S46: No), it is determined whether the predetermined temperature gradient can be maintained by adjusting the current value (S4).
8). In the case of nickel-metal hydride batteries, at the end of charging, not the current charging current, but the past charging history may cause a sudden drop in temperature, called overshoot. Judge. Here, when the overshoot has occurred (S48: Yes), the treatment is completed. On the other hand, if no overshoot has occurred (S48: N
o), proceed to S50, charge the battery with the current value determined in S44, and continue the charging process.

Next, the case where the refresh discharge is performed will be described. After the completion of the refresh discharge (S18: Ye
s) The temperature of the battery pack 50 is detected via the temperature detector 38 (S36). Here, it is assumed that the outside air temperature and the battery temperature are 20 ° C. When the refresh discharge is performed, the target charge time is calculated by subtracting the time required for the refresh discharge from the refresh discharge and charge completion time of 1 hour (S38). Here, the description is continued assuming that the refresh discharge requires 30 minutes and the target charging time is set to 30 minutes. Then, by searching the storage unit 39 holding the value of the above-described curve L with reference to FIG. 5, the temperature rise value 40 deg corresponding to the charging time of 30 minutes is determined, and the temperature gradient is calculated. (S4
0). Here, the gradient of a straight line b connecting the temperature 0 deg and the 50 deg on the curve L shown in FIG. Thereafter, the processes in S42 to S50 described above are performed, and the charging current is controlled so as to have a temperature gradient of the straight line b, thereby completing the charging in the target charging time of 30 minutes.

In the first embodiment, the necessity of refresh discharge of the battery is determined, and when it is determined that refresh discharge is necessary, the refresh discharge is performed before the start of charging.
Then, when the battery is refresh-discharged, the charging is completed in a shorter time than in the case where the quick charge is performed and the refresh discharge is not performed, and the total of the refresh discharge time and the charge time is calculated when the refresh discharge is not performed. And the charging time is almost the same. For this reason, even if the refresh discharge is automatically performed or the refresh discharge is not performed, the time from when the charging is completed to when the battery can be reused is the same. The battery can be charged without being conscious of the presence or absence of the battery, and the usability of the charging device that performs the refresh discharge can be improved. In addition, when the refresh discharge is not performed, the charge is performed in the same time as when the refresh discharge and the rapid charge are performed, so that the charge can be performed over a long time, and the battery life can be extended.

In the first embodiment, the battery pack 50
In order to determine whether refresh discharge is necessary based on the charge history of the storage unit (EEPROM) 61 provided in
The necessity of refresh can be accurately determined.

In the charging device of the first embodiment, the battery is charged while adjusting the current value so that the temperature rise value becomes the calculated temperature rise gradient. For this reason, it is possible to charge the battery so that the temperature at the time of completion of the charging becomes the attained target temperature value, and it is possible to charge a nickel-metal hydride battery or the like whose temperature rises remarkably in a short time so as not to become high. Here, the temperature rise gradient is controlled to be constant, but the charging time can be further reduced by controlling the charging current so as to have a predetermined pattern (for example, a mountain-shaped pattern).

In the above-described first embodiment, the time until the completion of charging is exactly the same between the case where charging is performed without performing refresh discharge and the case where charging is performed after performing refresh discharge. Even if it is substantially constant, it is possible to improve the usability of the charging device that performs the refresh discharge. In this case, when the refresh discharge is not performed, the charge time is fixed so that the normal charge for one hour is performed, and when the refresh discharge is performed, the charge time is fixed so that the quick charge is performed for 20 minutes. Will be possible.

Furthermore, in the above-described embodiment, charging is started immediately after refresh discharge is completed. However, after refresh discharge is completed, it is also preferable to start charging after a cooling time of the battery. In the present embodiment, since the charging current is controlled by the temperature, the charging can be completed in a target time even if the temperature of the battery is increased by the refresh discharge.

Further, in the above-described embodiment, the discharging unit is built in the charging device. Instead, an adapter is interposed between the charging device and the battery pack, and the discharging unit is built in the adapter. It is also possible.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a control circuit and a battery pack of a charging device according to a first embodiment of the present invention.

FIG. 2 is a perspective view illustrating an appearance of a charging device.

FIG. 3 is a perspective view illustrating an appearance of a battery pack.

4 is a side view of a battery drill using the battery pack shown in FIG.

FIG. 5 is an explanatory diagram illustrating a charging principle of the charging device according to the first embodiment.

FIG. 6 is a flowchart illustrating a flow of a process performed by a control unit of the charging device according to the first embodiment.

FIG. 7 is a flowchart illustrating a flow of a process performed by a control unit of the charging device according to the first embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Charging device 21 Discharge load 22 Power supply circuit 23 Fan 25 Charge / discharge switching part 26 Control part 27 Voltage detection part 28 Temperature detection part 50 Battery pack 58 Battery 61 EEPROM 70 Battery drill TM Temperature sensor

Claims (4)

[Claims] 1. A charging apparatus comprising: a refresh discharge unit for performing a refresh discharge of a battery; and a charging unit for charging a battery, wherein the charging unit performs a quick charge when a refresh discharge of the battery is performed. A charging device characterized in that charging is completed in a shorter time than when refresh refreshing is not performed. 2. A charging apparatus comprising: a refresh discharge unit for performing a refresh discharge of a battery; and a charging unit for charging a battery, comprising: a determination unit for determining whether or not the battery requires a refresh discharge; The unit performs a refresh discharge before the start of charging when the determination unit determines that the refresh discharge is required, and performs the quick discharge and the refresh discharge when the refresh discharge of the battery is performed. A charging device characterized in that charging is completed in a shorter time than when there is no charging device. 3. A charging device comprising: a refresh discharge unit for performing a refresh discharge of a battery; and a charging unit for charging a battery, comprising: a determination unit for determining whether or not a refresh discharge of the battery is required; The unit performs a refresh discharge before the start of charging when the determination unit determines that the refresh discharge is required, and performs the quick discharge and the refresh discharge when the refresh discharge of the battery is performed. A charging device, wherein charging is completed in a shorter time than in a case where no refresh discharging is performed, and the sum of the refresh discharging time and the charging time is made substantially equal to the charging time when refresh discharging is not performed. 4. The charging device according to claim 2, wherein the determination unit determines whether refresh discharge is necessary based on a charging history of a storage unit provided in the battery.