JP2010252506A - Charger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a charger for setting a charging voltage of the charger at or below a detection voltage value detected per unit battery in a secondary battery pack and changing the voltage value depending on the temperature of the secondary battery, in charging a plurality of batteries. <P>SOLUTION: In the charger for charging the secondary battery pack consisting of a plurality of batteries, the battery voltage and temperature of each unit battery are detected in the charger, the detected battery voltage for each unit battery is compared with an overvoltage protection value for protecting the unit batteries which varies depending on a temperature set in advance in the charger, and the charging control voltage value of the charger is set at an optimum charging voltage value not exceeding the overvoltage protection value, thereby sufficiently ensuring the charging capacity of the secondary battery which is currently charged. Further, the charging control voltage value is varied depending on the detected temperature, and thus, the optimum charging control depending on the temperature can be executed. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a charging device for charging a secondary battery pack of a plurality of batteries in which single cells are combined in series.

  In recent years, the market for portable electronic devices such as portable audio and digital still cameras has grown rapidly. Among them, in order to supply power to portable electronic devices, secondary batteries that can be charged and reused play an important role. And as a trend of the market, the secondary battery, which is a power source necessary for driving the electronic device, has become a market trend to increase its battery capacity so that the usage time of the electronic device can be made longer. .

  On the other hand, increasing the capacity of a secondary battery greatly affects the safety of the secondary battery. In Japan, in order to ensure the safety of the secondary battery, the conventional Electrical Appliance and Material Safety Law has New regulations for ion secondary batteries will be added and new regulations will be enforced. When a new technical standard is implemented, when charging a secondary battery pack of multiple batteries that combine single cells in series, the battery voltage of each single cell is detected so that the battery voltage of the single cell does not exceed a certain level. It is necessary to control the control voltage value according to the temperature of the secondary battery.

  In such a background, the conventional charging control method of the charging device does not detect each single cell voltage value in the secondary battery pack of the plurality of batteries in which the single cells are combined in series, and the secondary battery Since the control voltage value is not controlled according to the temperature, in order to comply with the newly enforced technical standards, a function to detect the cell voltage is installed, and the temperature of the secondary battery is further detected. There is a need to change the control voltage value according to the temperature so that the battery voltage of the unit cell does not exceed a certain level.

  Further, for a conventional charging system for charging a secondary battery pack of a plurality of batteries in which single cells are combined in series, a technique such as a method of accurately charging a charging control voltage of the secondary battery pack is known.

  Next, the conventional operation of FIG. 2 will be described.

  The charging device 1 starts charging the mounted battery pack 7 by connecting the thermistor 12 inside the battery pack 7 to the charging device.

  The charging voltage 5 of the charging device 1 is controlled by inputting the total voltage of the cells A10 and B11 to the charging voltage control operational amplifier 3 in the charging device, and charging the charging voltage 5 based on the reference voltage of the reference voltage regulator 4. Charge voltage control is performed by the voltage control operational amplifier 3, and the charge voltage 5 is output from the power supply circuit 2, and the charge control is performed as the total voltage of the cell A10 and the cell B11.

  Further, when the voltage values of the unit cells A10 and B11 are detected by the battery pack 7, and the detected voltage value becomes higher than a preset overvoltage protection value, the protection switch inside the battery pack 9 stops charging.

  Therefore, in order not to stop the charging in the middle, it is necessary to set the charging voltage 5 of the charging device 1 to a voltage value equal to or lower than the total overvoltage protection value for each unit cell. Therefore, it is necessary to set the charging voltage control value of the charging device low.

  FIG. 4 is a profile of temperature and charging control voltage according to the conventional control method.

  The charge control voltage is limited for charging at 45 ° C or higher according to the technical standards of the new Electrical Appliance and Material Safety Law. In the conventional charge control method, the charge control voltage is only one type of control at 8.400V. Therefore, charging at 45 ° C. or higher becomes impossible.

JP 2003-134686 A

  However, a function to detect the cell voltage is provided in the secondary battery pack, and the detection function detects the battery voltage for each cell, and the detected voltage reaches the control voltage setting value according to the temperature of the secondary battery. In the method of stopping charging in this case, the charging control voltage value of the charging device needs to be set to be equal to or lower than the detection voltage value detected for each single cell in the above-described secondary battery pack, so that charging is performed. There is a problem that the charge capacity value of the secondary battery is lowered, and the driving time of the electronic device is shortened compared to the conventional case.

  In a charging device that charges a secondary battery pack of a plurality of batteries in which single cells are combined in series, the battery voltage of each single cell is detected by the charging device, and the detected voltage value of each single cell is preset in the charging device. Compared with the overvoltage protection value for protecting the unit cell, the voltage value that has changed for each cell so that the overvoltage protection value is not exceeded is set to a constant voltage value as much as possible by the charging control of the charging device. A charging device characterized by constant voltage charging control.

  According to the present invention, in a charging device for charging a secondary battery pack of a plurality of batteries in which single cells are combined in series, the battery voltage and temperature of each single cell are detected by the charging device, and the detected single cells Compare the battery voltage of each battery with the overvoltage protection value that protects the unit cell that is variable according to the temperature set in advance in the charging device, so that the charging control voltage value of the charging device does not exceed the overvoltage protection value. By setting the optimal charging voltage value, the charging capacity of the secondary battery being charged can be secured sufficiently, and the charging control voltage can be varied according to the detected battery temperature, and the temperature It is possible to charge with the optimum charge control voltage value according to the condition.

The circuit block diagram regarding the charge voltage control inside the charging device of this invention Circuit configuration diagram related to charge voltage control inside a conventional charging device Profile diagram of temperature and charge control voltage value by the control method of FIG. Profile diagram of temperature and charge control voltage value by conventional control method

  The best mode for carrying out the present invention will be described below with reference to the drawings.

(Embodiment 1)
FIG. 1 is a circuit configuration diagram relating to charge voltage control inside the charging apparatus according to Embodiment 1 of the present invention. As in the conventional case, the charging device 1 starts charging the mounted battery pack 7 by connecting the thermistor 12 inside the battery pack 7 to the charging device.

  Moreover, the intermediate terminal 14 is installed in the charging terminal of the battery pack 7 and the charging device 1 so that the voltage value of each of the cell A10 and the cell B11 can be detected.

  The voltage value of the single cell A10 and the voltage value of the single cell B11 are detected by the voltage detection circuit 13 for the single cell voltage, and the high voltage value of each of the voltage values is supplied to the charge control voltage setting circuit 4 with a built-in reference voltage regulator. Output. Further, the temperature of the thermistor 12 mounted inside the battery pack 7 is detected by the charge control voltage setting circuit 4 with a built-in reference voltage regulator, and an optimum charge control voltage value is set from the voltage value of the single cell and the detected temperature. Then, the charging voltage control is performed using the charging control voltage value and the charging voltage 5 which is the total voltage of the unit cell A10 and the unit cell B11 with the optimum charging control voltage value.

  By this control method, the charging voltage control method of the charging device 1 can control the constant voltage control of the unit cell A10 and the constant voltage control of the unit cell B11, and by performing the constant voltage control for each unit cell, It becomes possible to ensure the safety of the single cell by the charging control of the charging device. Therefore, the overvoltage protection control for each single cell inside the secondary battery pack is unnecessary, and it is not necessary to set the constant voltage control value of the charging device low.

(Embodiment 2)
FIG. 3 is a diagram of the temperature and charge control voltage profile of the control method according to Embodiment 2 of the present invention.

  The charging device performs charging control at 8.400 V when the temperature of the secondary battery is 45 ° C. or lower, performs charging control at 8.200 V when the temperature of the secondary battery is 45 ° C. to 50 ° C., and is 8. Charge control is performed at 100V.

  By this control, the charge control voltage can be changed according to the temperature of the secondary battery, so that charging can be performed even at 45 ° C. or higher.

  According to the present invention, in a charging device for charging a secondary battery pack of a plurality of batteries in which single cells are combined in series, the battery voltage and temperature of each single cell are detected by the charging device, and each detected single cell is Compare the battery voltage with the overvoltage protection value that protects the single cell that changes according to the temperature set in the charging device in advance, and the charging control voltage value of the charging device does not exceed the overvoltage protection value. By setting the voltage value, it is possible to sufficiently secure the charging capacity of the charged secondary battery.

DESCRIPTION OF SYMBOLS 1 Charging device 2 Power supply circuit 3 Operational amplifier for charging voltage control 4 Reference voltage regulator 5 Charging voltage 6 Charging terminal of charging device 7 Battery pack 8 Charging terminal of battery pack 9 Protection switch inside battery pack 10 Single cell A
11 Cell B
12 Thermistor 13 Voltage detection circuit 14 Intermediate terminal

Claims (3)

In a charging device that charges a secondary battery pack of a plurality of batteries in which single cells are combined in series, the battery voltage of each single cell is detected by the charging device, and the detected voltage value of each single cell is preset in the charging device. Compared with the overvoltage protection value for protecting the unit cell, the voltage value that has changed for each cell so that the overvoltage protection value is not exceeded is set to a constant voltage value as much as possible by the charging control of the charging device. A charging device characterized by constant voltage charging control. The overcharge protection value for protecting a single cell can be varied according to the detected temperature in the charging device according to the detected temperature of the secondary battery to be charged. Charging device. In the charging device, the temperature of the secondary battery to be charged is detected, and the overvoltage protection value for protecting the cell set in the charging device in advance is varied according to the detected temperature, and the overvoltage protection value is exceeded. 3. The charging device according to claim 2, wherein the charging control voltage value of the charging device is varied so that the charging control is performed with an optimal charging control voltage value according to the temperature of the secondary battery.

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