JP2010252505A - 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 of a plurality of batteries in which unit batteries are combined in series, the voltage value and temperature of the batteries are detected, an overvoltage protection value for protecting the unit batteries can be varied depending on the detected temperature, a signal from the battery pack for outputting a signal when the voltage value of the unit battery reaches a predetermined voltage is detected, and a charging current is varied. <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 enforced, when charging a secondary battery pack of a plurality of batteries in which single cells are combined in series, the battery voltage for each single cell is detected, and the voltage value does not fall below a certain voltage value. Unless the control method is adopted, it is expected that technical standards cannot be satisfied.

  Further, it is expected that the voltage value must be varied according to the detected temperature of the battery. In the conventional charging device, the voltage value of each unit cell in the secondary battery pack of the plurality of cells obtained by combining the unit cells in series cannot be detected, and only the total voltage value of the plurality of cells is detected. In order to comply with the newly enforced technical standards, a function to detect the cell voltage is installed in the secondary battery pack so that the cell voltage of the cell does not exceed a certain level. There was a need to control. Further, it is necessary to detect the temperature of the secondary battery and set the charge control voltage value according to the temperature.

  In addition, with regard to a charging system for charging a secondary battery pack of a plurality of batteries in which single cells are combined in series, there is a technology that detects a voltage value for each single cell and performs charge protection for the voltage value. Are known.

  Next, the conventional operation of FIG. 3 will be described.

  When the thermistor 13 inside the battery pack 8 of the battery pack 8 is connected to the charging device 1, the charging device 1 starts charging the attached battery pack 8.

  The control method of the charging voltage 15 of the charging device 1 is such that the total voltage of the unit cell A11 and the unit cell B12 is detected by the charging control IC 3 inside the charging unit, and the secondary battery pack to be charged is fully charged. The charging control IC 3 performs constant voltage control, and the charging current value is detected by the charging current detection resistor 6 and controlled by the charging control IC 3.

  Further, the voltage values of the cell A11 and the cell B12 are detected by the battery pack 8, and when the detected voltage value becomes higher than a certain value, the charging is stopped by the control IC 10 inside the battery pack. Yes.

  However, to detect the voltage values of the unit cells A11 and B12 in the battery pack 8, it is necessary to set the charging voltage 15 of the charging device 1 to be lower than the voltage value for controlling the protection described above in the battery pack 8. There is.

JP 2003-134686 A

  However, in the secondary battery pack, a function for detecting the cell voltage is provided, the battery voltage for each cell is detected by the detection function, and charging is stopped when the detected voltage reaches the set value. The constant voltage control voltage value of the secondary battery charger that detects the battery voltage of a plurality of batteries combined in series and controls the charging voltage value at a constant voltage is stored in the secondary battery pack described above. Since it is necessary to set it below the detection voltage value detected for each unit cell, the charge capacity value of the secondary battery to be charged becomes lower, and the driving time of the electronic device becomes shorter than the conventional one. There are challenges.

  The present invention solves such a problem, and in a charging device for charging a secondary battery pack of a plurality of batteries in which single cells are combined in series, the voltage value and temperature of the single cells are detected, and the temperature is determined according to the temperature. By detecting the signal of the battery pack that outputs a signal when the voltage value of the cell reaches the overvoltage protection value for protecting the cell that can be varied, the charging current of the charging device is reduced, By performing control to reduce the voltage value of the unit cell and repeating the operation, the battery capacity is gradually increased so that the unit cell voltage does not exceed the overvoltage protection voltage value, and the charged secondary battery is more fully filled. Provided is a charging device that can be charged to a state close to charging, further varies a charging control voltage according to the detected battery temperature, and can be charged with an optimum charging control voltage value corresponding to the temperature. .

  In order to solve the above-mentioned conventional problems, in a charging device for charging a secondary battery pack of a plurality of batteries in which single batteries are combined in series, the voltage value and temperature of the single battery are detected, and the single battery is charged according to the detected temperature. The overvoltage protection value for protecting the battery can be varied, and when the voltage value of the cell reaches the specified voltage, the signal from the battery pack that outputs the signal is detected and the charging current can be varied. This is a characteristic charging device.

  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 voltage value and temperature of the single cells are detected, and the single cells that vary according to the temperature are protected. By detecting the battery pack signal that outputs a signal when the voltage value of the cell reaches the overvoltage protection value, the charging current of the charging device is reduced and the voltage value of the cell is reduced, and its operation By repeating the above, it is possible to gradually increase the battery capacity so that the unit cell voltage does not exceed the overvoltage protection voltage value, and to sufficiently secure the charging capacity of the secondary battery to be charged. Furthermore, the charge control voltage can be varied according to the detected battery temperature, and charging can be performed with an optimum charge control voltage value corresponding to the temperature.

FIG. 3 is a circuit configuration diagram inside the charging apparatus shown in Embodiment 1 of the present invention. Circuit diagram inside charging device shown in embodiment 2 of the present invention Circuit diagram inside the conventional charger Correlation diagram of charging current and charging capacity of the present invention Correlation diagram of conventional charging current and charging capacity 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

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  However, the embodiment described below specifically explains the present invention, and the present invention does not specify the charging device and the charging method as follows.

(Embodiment 1)
A circuit diagram of the present invention according to claim 1 of FIG. 1 will be described.

  The charging device 1 starts charging the battery pack 8 attached when the thermistor 13 in the battery pack 8 of the battery pack 8 is connected to the charging device 1 as in the conventional case.

  Further, a signal addition terminal 17 for mutual communication is added to the battery pack 8 and the charging terminal of the charging device 1.

  The control method of the charging voltage 15 of the charging device 1 is such that the total voltage of the unit cell A11 and the unit cell B12 is detected by the charging control IC 3 inside the charging unit, and the secondary battery pack to be charged is fully charged. The charge control IC 3 performs constant voltage control.

  The charging current value is detected by the charging current detection resistor 6 and controlled by the charging control IC 3.

  When the battery pack 8 detects the voltage values of the cell A11 and the cell B12 and the detected voltage value reaches the overvoltage protection value set in the battery pack 8, the charge control IC 3 inside the battery pack 8 Communicates with the charging device 1 that the unit cell voltage in the battery pack 8 has reached the overvoltage protection voltage via the signal additional terminal 17.

  And the charging device 1 reduces the voltage value of a single battery by reducing the charging current 16 by receiving the communication signal. In this way, the charging current is reduced by communication between the battery pack 8 and the charging device 1, and the single battery voltage value can be controlled so as not to exceed the overvoltage protection value set inside the battery pack 8.

  In addition, the above-described control is repeated, and the charging current is gradually reduced to increase the battery capacity so that the cell voltage does not exceed the overvoltage protection value. It is possible to secure a sufficient capacity value.

  Further, by detecting the temperature of the thermistor 13 mounted on the battery pack 8, the charge control voltage value of the charging device 1 can be varied.

(Embodiment 2)
Next, a diagram of the present invention according to claim 2 of FIG. 2 will be described.

  The charging device 1 starts charging the battery pack 8 attached when the thermistor 13 in the battery pack 8 of the battery pack 8 is connected to the charging device 1 as in the conventional case.

  The control method of the charging voltage 15 of the charging device 1 is such that the total voltage of the unit cell A11 and the unit cell B12 is detected by the charging control IC 3 inside the charging unit, and the secondary battery pack to be charged is fully charged. The charge control IC 3 performs constant voltage control. The charging current value is detected by the charging current detection resistor 6 and controlled by the charging control IC 3.

  Further, when the voltage values of the unit cell A11 and the unit cell B12 are detected by the battery pack 8, and the detected voltage value reaches the overvoltage protection value set in the battery pack, the battery pack 8 is inside the battery pack. By short-circuiting the thermistor short switch 14, it can be transmitted to the charging device 1 that the cell voltage has reached the overvoltage protection voltage.

  And the charging device 1 detects the short circuit of the thermistor 13 terminal, and reduces the voltage value of a single cell by reducing the charging current 16.

  Thus, when the charging device 1 detects the short circuit of the thermistor terminal of the battery pack 8, the charging device 1 reduces the charging current, and the single cell voltage value does not exceed the overvoltage protection value set inside the battery pack. Can be controlled in the same way.

  Further, the signal addition terminal 17 is added by repeating the above-described control and gradually reducing the charging current to increase the battery capacity so that the cell voltage does not exceed the overvoltage protection value. It is possible to sufficiently secure the charge capacity value of the battery pack being charged.

  FIG. 5 shows a change in the charge capacity value based on the above-described conventional operation.

  Hereinafter, the operation of FIG. 5 will be described.

  The horizontal axis represents the charging time, and shows the charging voltage of the single cell, the signal from the battery pack 8 to the charging device 1, the charging current, and the charging capacity, respectively.

  The charging voltage control of the charging device 1 controls the charging voltage with respect to the total battery voltage value of the unit cell A11 and the unit cell B12. Further, for overvoltage protection for ensuring the safety of the battery, the voltage value for each unit cell. Is detected in the secondary battery pack, and when the voltage value of the unit cell reaches the set value, the charging is stopped.

  Therefore, it is necessary to set the charging voltage control value of the charging device to be equal to or less than the total voltage value of the overvoltage protection value for each unit cell described above. Therefore, the charging voltage control value of the charging device needs to be set low, and the charging current 16 shifts from the constant current region to the constant voltage control region that controls the charging voltage to a constant value. Since a typical charge capacity value has a low charge voltage, a sufficient charge capacity value cannot be secured.

  FIG. 7 is a profile of temperature and charge 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.

  FIG. 6 is a profile of the temperature and charge control voltage value of the control method described above.

  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 8 when the temperature of the secondary battery is 50 ° C. or higher. .Control charging 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.

  The charging device according to the present invention is a charging device for charging a secondary battery pack of a plurality of batteries in which single cells are combined in series, and detects the voltage value and temperature of the single cells and protects the single cells that vary according to the temperature. By detecting the signal of the battery pack that outputs a signal when the voltage value of the unit cell reaches the overvoltage protection value for controlling, the charging current of the charging device is reduced, and the control to reduce the voltage value of the unit cell is performed. By repeating the operation, the battery capacity can be gradually increased so that the cell voltage does not exceed the overvoltage protection voltage value, and the charged secondary battery can be charged to a state close to full charge. The charging capacity of the charged secondary battery can be sufficiently secured, and the charging voltage can be varied according to the temperature, so that the optimum charging control according to the temperature is possible.

1 Charging Device 2 Power Supply Circuit 3 Charging Control IC
4 Reference Voltage Regulator 5 Voltage Dividing Resistor 6 Charging Current Detection Resistor 7 Charging Device Charging Terminal 8 Battery Pack 9 Battery Pack Charging Terminal 10 Control IC Inside Battery Pack
11 Cell A
12 cell B
13 Thermistor 14 Thermistor Short Switch 15 Charging Voltage 16 Charging Current 17 Signal Additional Terminal

Claims (5)

In a charging device for charging a secondary battery pack of a plurality of batteries in which single cells are combined in series,
The voltage value and temperature of the unit cell are detected, and the overvoltage protection value for protecting the unit cell can be varied according to the detected temperature, and when the voltage value of the unit cell reaches its specified voltage, A charging device characterized by detecting a signal from a battery pack that outputs a voltage and varying a charging current. In the charging device, when the voltage value of the unit cell is detected and the voltage value reaches an overvoltage protection value for protecting the unit cell, the temperature of the unit cell is converted into an electric signal and the signal is output. The charging device according to claim 1, wherein the charging current is varied by detecting that the terminal is short-circuited. 3. The charging device according to claim 1 or 2, wherein by changing the charging current, the voltage value of the secondary battery pack to be charged is gradually reduced, and the overvoltage protection operation of the single battery inside the secondary battery pack is canceled. The charging device according to claim 1 or claim 2, wherein In the charging device according to claim 3, after the overvoltage protection of the unit cell in the secondary battery pack to be charged is canceled, the charging is continued by outputting the optimum charging current again, and the overvoltage protection operation and unit of the unit cell are performed. 3. The charging device according to claim 1, wherein the secondary battery to be charged can be charged to a state close to full charge by repeatedly releasing the overvoltage protection of the battery and varying the charging current. . 5. The charging device according to claim 4, wherein the temperature of the secondary battery to be charged is detected, the charging control voltage value of the charging device is varied according to the temperature, and the optimum charging according to the temperature of the secondary battery to be charged is performed. 3. The charging device according to claim 1, wherein charging is performed with a control voltage.

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