JP2002335640A - Charger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a charger which can realize the charging operation, while protecting the battery from being lowered in temperature. SOLUTION: Cooling of battery is continued with a fan 23 even after the termination of charging operation. Whether or not a temperature gradient of battery (temperature change) is negative is determined (S48). If the temperature gradient is negative (S48: YES), the fan 23 stops operation thereof (S54). Thereby, the battery is cooled to the normal temperature and is also protected from excessively being lowered in temperature.

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 for cooling a battery by blowing a fan to the battery during charging.

[0002]

2. Description of the Related Art At present, a rechargeable battery which can be repeatedly used as a power source of a power tool or the like is used together with a charging device which performs rapid charging by flowing a large current through the battery. That is,
By rapidly charging the battery in about 20 minutes, it is possible to continuously use the power tool while replacing the charged battery. There is a charging device provided with a fan to forcibly air-cool the battery so that the battery does not become hot at the time of the rapid charging and the life is not deteriorated. In such a charging apparatus, a fan or the like is used to keep the fan running for a predetermined time after charging is completed, and to continue cooling the battery after charging is completed.

[0003]

However, if the fan continues to be operated after charging is completed in a low temperature state, such as when a charging device is used outdoors in winter, the battery cools rapidly until the temperature becomes low, and the battery life is shortened. The battery will not be able to exhibit its original performance due to shrinkage and low temperature.

To cope with such a problem, for example, Japanese Patent Application Laid-Open Nos. 2000-36327 and 11-55869 have been proposed. Japanese Patent Application Laid-Open No. 2000-36327 discloses a technique for preventing supercooling by detecting and controlling the ambient temperature together with the battery temperature. However, since an ambient temperature sensor is used together with a plurality of temperature sensors, there is a problem that the number of sensors increases and the cost increases. on the other hand,
Japanese Patent Application Laid-Open No. H11-55869 discloses a configuration in which a battery is cooled and heated by using a Peltier element. However, since an expensive Peltier element is used, it is difficult to apply it to a general-purpose charging device.

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 charge a battery so that the temperature of the battery does not become low.

[0006]

According to one aspect of the present invention, there is provided a charging device for cooling a battery by blowing a fan to the battery during charging, and detecting a temperature of the battery after the charging of the battery is completed. A technical feature is that the detected temperature change is calculated, the air blowing is continued until the changed amount reaches a predetermined value, and the air blowing is terminated when the temperature reaches the predetermined value.

According to the first aspect, the air blowing is continued even after the charging of the battery is completed. That is, the high temperature state of the battery is prevented from continuing after the charging is completed. Then, when the amount of change in the battery temperature reaches a predetermined value, the blowing is terminated. That is, the temperature of the battery is not excessively lowered. For this reason, charging can be completed so that the battery temperature does not reach a high or low temperature and becomes a normal temperature, thereby extending the life of the battery and exerting its original performance.

According to the second aspect, when the variation of the battery temperature is equal to or less than a predetermined value or when the variation becomes negative, the air blowing is terminated. That is, the temperature of the battery is not excessively lowered. For this reason, the charging can be completed so that the temperature of the battery does not become low but becomes normal temperature.

According to a third aspect of the present invention, there is provided a charging device for cooling a battery by blowing air to the battery during charging.
The battery temperature is detected, a change in the detected temperature is calculated, and it is determined whether the battery temperature is low.If the battery temperature is equal to or lower than a set low temperature value, the calculated change is equal to or higher than a predetermined value. In this case, the technical feature is to continue blowing.

In the third aspect, when the temperature is equal to or less than the set low temperature value and the calculated temperature change is equal to or more than a predetermined value, the air blowing is continued even after the charging is completed. For this reason, for example, when charging a battery that is stored outdoors in winter and has an extremely low temperature, indoors at room temperature, even if the battery temperature is lower than room temperature (room temperature) at the time of completion of charging, It can continue to blow and quickly warm to room temperature.

According to a fourth aspect of the present invention, there is provided a charging device for cooling a battery by blowing a fan to the battery during charging.
Calculate the detected temperature change, determine whether the battery temperature is high, and if the calculated change is equal to or higher than a predetermined value, stop blowing when the calculated change is equal to or higher than a predetermined value. Is a technical feature.

According to a fourth aspect of the present invention, when the temperature is equal to or higher than the set high temperature value and the calculated temperature change is equal to or higher than a predetermined value, the air blow is stopped during charging or when charging is completed. . For this reason, for example, when the ambient temperature is considerably higher than the battery temperature, such as when the battery is charged in an extremely high-temperature atmosphere such as in a car under the scorching sun, by stopping the fan, the battery is suddenly charged during charging or when the charging is completed. A rise in temperature can be avoided.

[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 battery pack 50 is loaded in charging device 10. FIG. 2 shows the appearance of the charging device 10. FIG. 3 shows the 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 incorporates a plurality of nickel-metal hydride batteries 58 that 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 EE for holding information such as the type of the battery pack.
And a PROM 61. The temperature sensor TM is composed of a thermistor whose electric resistance changes according to the 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, and a portion located on one end side of the fitting portion 52 has a vertical direction. Is provided with a hook 54 which can enter and exit the device. This hook 5
4 is formed integrally with a lever 55 provided on a 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.

At the upper end side of the casing 51, a ventilation port 56 is provided so as to be sandwiched between the fitting portions 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. Thus, 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 plus terminal and a minus terminal (not shown) are provided in the plus terminal groove 57 and the minus 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 receive. Thus, the chuck 76 can be rotated by a 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 resin housing 11, and the housing 11 has a fitting portion 12 into 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 that can take in the air to be sent in from the outside are integrally formed. 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 vent 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. Thereby, 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 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 temperature detection unit 28 is configured to be able to detect the temperature of the battery being charged by the temperature sensor TM,
The voltage detector 27 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 sends air taken in from the outside via the air inlet 13 shown in FIG. 2 to the air vent 56 (see FIG. 3) of the battery pack 50 through the air blow port 16 to force the battery 58 in the battery pack 50. Air cool.

The control unit 26 differentiates the temperature value output from the temperature detection unit 28 to obtain a temperature rise value, and then calculates a predetermined current value based on the current value control information in the storage unit 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. The control unit 26 includes a battery 58
Is detected, and the fan 23 is driven if necessary.
The battery 58 is cooled during and after charging.

The above-described power supply circuit 22, charging current control unit 24, control unit 26, voltage detection unit 27, temperature detection unit 2
8. The storage unit 29 and the like have substantially the same configuration as that of the charging device disclosed in the earlier patent application (Japanese Patent Application No. 11-081247) filed by the present applicant, and detects the temperature of the battery 58 by the temperature sensor TM. The charging is controlled by controlling the charging current based on the detected temperature.

When the battery pack 50 is mounted on the fitting portion 12 of the charging device 10 configured as described above, the control unit 26 operates according to a predetermined algorithm by the power supply circuit 22, the charging current control unit 24, and the voltage detection unit 27. The battery 58 in the battery pack 50 is charged by controlling the temperature detection unit 28, the storage unit 29, and the like. Then, during charging, a capacity display lamp for displaying the capacity of the battery pack 50 is turned on, and when charging is completed, charging is stopped and the fact is notified by the lamp.

The charging process by the control unit 26 of the charging device will be described with reference to FIGS. When the battery pack 50 is loaded in the charging device 10, the control unit 26 detects the battery voltage by the voltage detection unit 27 and / or detects the battery temperature by the temperature detection unit 28, and then performs the loading. The information is detected (S12: Yes), and the information in the EEPROM 61 is read (S14). Next, a control program matching the model of the battery pack 50 in the control program for each battery pack stored in the storage unit 29 is searched (S16). Then, the rotation of the fan 23 is started, and the cooling of the battery 58 in the battery pack 50 is started.

Subsequently, the temperature of the battery is detected by the voltage detecting section 27 (S20), and the temperature of the battery 58 is detected by the temperature detecting section 28 (S22). It is determined whether the charging is completed based on the battery voltage / temperature (S24). Until the charging is completed (S24: No), the charging current determined based on the battery voltage / temperature is supplied from the power supply circuit 22 to the battery 58. (S2
6). That is, as described above, a temperature rise value is obtained by differentiating the temperature value output from the temperature detection unit 28, and then a predetermined current value is calculated based on the control program in the storage unit 29. Charge current control unit 24 as a command value
To control the charging current. When the completion of the charging is detected based on the battery temperature and the voltage (S24: Ye
s) Stop charging and adjust the timing of stopping the fan.

The process for adjusting the timing of stopping the fan 23 will be described with reference to the flowchart of FIG. 6 and FIG. 9 showing changes in battery temperature. First, a timer (for example, 30 minutes) for defining the maximum value of the stop timing is set (S32). Next, the temperature of the battery 58 is detected (S
34), a temperature gradient is calculated by differentiating the temperature value, that is, a change in temperature is calculated (S36). Then, it is determined whether or not the timer has timed out (S38). When the timer has timed out (S38), the fan 23 is stopped and the process is terminated (S5).
4).

Before the timeout occurs (S38: N
o), it is determined whether the battery temperature is high (S40). When the temperature of the battery is high (S40: Yes), it is determined whether the temperature gradient has turned negative, that is, whether the battery temperature has dropped (S42), and when the temperature has dropped (S42:
Yes), returning to S34 to continue cooling the battery. Thus, the battery is prevented from being in a high temperature state, and the battery life is extended.

On the other hand, when the battery temperature has risen (S42: No), a predetermined time (for example, 1
Minutes) have elapsed (S44). Here, FIG.
As shown in (A), when the charging is completed and the temperature continues to rise even after one minute has passed after the current stops flowing to the battery (S44: Yes), the ambient temperature is higher than the battery temperature. High, for example, charging in a car under the scorching sun, and the case where the rise of the battery temperature is accelerated by rotating the fan 23, the fan 23 is stopped (S5).
4).

If the battery temperature is not high (S40:
No), it is determined whether the battery temperature is normal temperature (for example, 15 ° C. to 50 ° C.) (S46). Here, the normal temperature is determined based on the life of the battery and means that the temperature is not extremely high or low enough to shorten the life of the battery. If the temperature is normal (S46: Yes), it is determined whether the battery temperature gradient is negative (S48). If the battery temperature gradient is negative as shown in FIG. 9B, the battery temperature gradient is negative (S48: Yes).
s) The fan 23 is stopped (S54). This allows
The battery is cooled down to normal temperature and excessive cooling is prevented. Here, the fan 23 is stopped when the temperature gradient becomes negative. Alternatively, the fan may be stopped when the temperature gradient becomes zero or when the temperature gradient becomes lower than a certain value. Can also.

Here, when the temperature gradient is positive, it is determined whether the temperature gradient is equal to or more than a predetermined value (S50). FIG. 9 (C)
In the case where the charging is completed and the temperature continues to rise by a predetermined amount or more even after the current stops flowing to the battery (S50:
Yes), the ambient temperature is higher than the temperature of the battery, for example, charging in a car under hot weather, etc.
By rotating, the battery temperature rises faster,
The fan 23 is stopped (S54).

On the other hand, if the temperature gradient rises below the predetermined value (S50: No), the flow returns to S34 to continue cooling the battery. Thus, the battery is prevented from being in a high temperature state, and the battery life is extended.

On the other hand, when the temperature is not room temperature (S46: N
o), that is, when the battery temperature is low at the time of completion of charging, the gradient of the battery temperature is minus, that is, when the battery temperature is further lowered in a low temperature state (S52: Ye)
s), the fan 23 is stopped (S54), and the battery temperature is prevented from decreasing more rapidly from the low temperature state. Conversely, FIG.
As shown in (D), when the battery temperature has risen (S52: No), the battery in a low temperature state is charged under an atmosphere of normal temperature. For example, a battery used outdoors in winter is replaced with a room at room temperature. In this case, the process returns to S34, and continues to rotate the fan 23 to quickly raise the battery temperature to room temperature. As a result, the life of the battery is extended by shortening the time in which the battery is kept at a low temperature, and the original capacity can be generated by bringing the battery into a normal temperature state.

In the charging device of the first embodiment, the air blowing is continued even after the charging of the battery is completed. That is, the battery is cooled so that it does not become high after the completion of charging. Then, when the amount of change in the battery temperature reaches a predetermined value, the blowing is terminated. That is, the temperature of the battery is not excessively lowered. For this reason, charging can be completed so that the battery temperature does not reach a high or low temperature and becomes a normal temperature, thereby extending the life of the battery and exerting its original performance.

Next, a charging device according to a second embodiment of the present invention will be described. The mechanical configuration of the charging device according to the second embodiment is the same as that of the first embodiment described above with reference to FIGS.
The description is omitted because it is similar to the embodiment.

The charging process of the charging device according to the second embodiment will be described with reference to FIGS. In the charging device of the first embodiment, the rotation of the fan 23 is started at the same time as the start of charging, and the fan is stopped with completion of predetermined conditions after completion of charging. On the other hand, in the second embodiment, the battery temperature is monitored, and the fan 23 is rotated and stopped during charging according to the temperature.

When the battery pack 50 is loaded into the charging device 10, the control unit 26 detects the battery voltage by the voltage detection unit 27 and / or detects the battery temperature by the temperature detection unit 28. (S12: Ye)
s) The information in the EEPROM 61 is read (S14).
Next, a control program matching the model of the battery pack 50 in the control program for each battery pack stored in the storage unit 29 is searched (S16).

Subsequently, the temperature of the battery is detected by the voltage detector 27 (S20), and the temperature of the battery 58 is detected by the temperature detector 28 (S22). It is determined whether the charging is completed based on the battery voltage / temperature (S24). Until the charging is completed (S24: No), the charging current determined based on the battery voltage / temperature is supplied from the power supply circuit 22 to the battery 58. (S2
6). That is, as described above, a temperature rise value is obtained by differentiating the temperature value output from the temperature detection unit 28, and then a predetermined current value is calculated based on the control program in the storage unit 29. Charge current control unit 24 as a command value
To control the charging current.

Subsequently, the processing shifts to the control processing of the fan 23 shown in FIG. First, a temperature gradient, that is, a change in temperature is calculated by differentiating the battery temperature value detected in S22 (S36). Then, it is determined whether the battery temperature is high (S40). If the battery temperature is not high (S40:
No), it is determined whether the battery is at normal temperature (S46). When the battery is not at room temperature, that is, when the battery is at low temperature (S46:
No), the fan 23 is not rotated (S54). Then, after judging whether or not charging is completed (S58: No), S20
Return to and continue charging.

On the other hand, if the battery temperature is at room temperature at the start of charging, or if charging is started from a low temperature state and reaches room temperature (S46: Yes), it is determined whether the temperature gradient is negative (S48). : No), it is determined whether the temperature gradient is equal to or greater than a predetermined value (S50). If the temperature continues to rise by a predetermined amount or more (S50: Yes), the ambient temperature is higher than the battery temperature, for example, charging in an automobile under the hot sun, and the like. Since the rise is accelerated, the fan 23 is stopped (S5).
4). On the other hand, when the gradient of the temperature rise is equal to or lower than the predetermined value (S50: No), the fan 23 is rotated (S50).
56) To suppress the rise in battery temperature. Then, when the temperature gradient becomes negative (S48: Yes), the process proceeds to S54 and the fan 23 is temporarily stopped.

If the battery temperature is high (S4
0: Yes), it is determined whether the temperature gradient is equal to or greater than a predetermined value (S)
42). If the temperature continues to rise above a predetermined value (S42:
Yes), since the ambient temperature is higher than the temperature of the battery and the temperature of the battery is increased faster by the rotation of the fan 23, the fan 23 is stopped (S54). On the other hand, when the temperature rise gradient is equal to or lower than the predetermined value (S42: No), the fan 23 is rotated (S56) to suppress the heat generation so that the battery temperature becomes the normal temperature.

The above process is repeated to complete charging,
When the completion of the charging is detected based on the battery temperature and the voltage (S24: Yes in FIG. 7), the charging is stopped, and the timing of stopping the fan is adjusted. When the battery temperature is high (S40: Yes), the fan 23 is rotated (S56) after judging whether the temperature gradient is equal to or more than a predetermined value (S42: No), and the battery temperature is cooled to normal temperature. I do.

Here, when the battery is cooled from the high temperature state to the normal temperature, or when the charging of the battery is completed at the normal temperature state (S46: Yes), it is determined whether the temperature gradient is negative (S48: No). Until the battery temperature becomes negative (S48: No), the rotation of the fan 23 is continued via S50 (S56). When the temperature gradient becomes negative (S48: Yes), the process proceeds to S54, in which the fan 23 is stopped, and after judging whether charging is completed (S58: Yes),
All processing ends. Here, the fan 23 is stopped when the temperature gradient becomes negative, but when the absolute value of the negative temperature gradient becomes equal to or more than a predetermined value, the fan 2 is stopped.
3 can also be stopped.

In the charging device according to the second embodiment, the blowing is intermittently performed according to the battery temperature even while the battery is being charged. For this reason, the battery can be charged at room temperature, and the life can be extended. Then, even after the charging of the battery is completed, the blowing is continued as necessary. That is, the temperature of the battery does not become high after charging is completed. Then, when the amount of change in the battery temperature reaches a predetermined value, the blowing is terminated. That is, the temperature of the battery is not excessively lowered. For this reason, charging can be completed so that the battery temperature does not reach a high or low temperature and becomes a normal temperature, thereby extending the life of the battery and exerting its original performance.

[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 showing the appearance of the 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 a flowchart illustrating a flow of a process performed by a control unit 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 embodiment.

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

FIG. 8 is a flowchart illustrating a flow of a process performed by a control unit of the charging device according to the second embodiment of the present invention.

FIGS. 9A, 9B, 9C, and 9D are graphs showing battery temperature changes during and after charging.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Charging device 22 Power supply circuit 23 Fan 26 Control part 26a Communication port 27 Voltage detection part 28 Temperature detection part 50 Battery pack 58 Battery 61 EEPROM 70 Battery drill TM Temperature sensor

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5G003 BA01 CA11 CB01 GC05 5H030 AA01 AS12 BB01 FF24 5H031 CC05 KK08

Claims (4)

[Claims] 1. A charging device that cools a battery by blowing a fan to the battery during charging, detects a temperature of the battery after charging of the battery is completed, calculates a change in the detected temperature, and calculates a change in the detected temperature. A charging device characterized in that the air blowing is continued until a predetermined value is reached, and the air blowing is terminated when the air flow reaches the predetermined value. 2. The charging device according to claim 1, wherein the predetermined value is that the temperature change is equal to or less than a predetermined value or the change is negative. 3. A charging device for cooling a battery by blowing air to the battery during charging, detecting a temperature of the battery after completion of charging the battery, calculating a change in the detected temperature, and calculating a temperature of the battery. Is determined to be a low temperature, and when the calculated change is equal to or more than a predetermined value, the air blowing is continued when the calculated change is equal to or more than a predetermined value. 4. A charging device for cooling a battery by blowing a fan to the battery during charging, detecting a temperature of the battery, calculating a change in the detected temperature, and determining whether the temperature of the battery is high. A charging device that stops blowing when the calculated change is equal to or greater than a predetermined value when the temperature is equal to or higher than the set high temperature value.