JPH02285938A - Charger - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a charging device for batteries, etc., and is used to quickly fully charge a battery.

[Prior Art] It is generally required that batteries and the like be charged in a short period of time. Therefore, rapid charging is often used, but rapid charging tends to lead to overcharging, which shortens the life of the battery. For this reason, in conventional quick charging devices, charging is controlled by setting the charging time using a timer or by detecting the terminal voltage of the battery. However, these charging control methods either stop charging before overcharging to avoid overcharging, or use flow charging to avoid overcharging the battery (which can quickly fully charge the battery). There were requests for a charging device, and improvements were desired.

[Problems to be Solved by the Invention] This invention attempts to solve the problem that occurs when conventional charging devices cannot accurately detect when the battery is fully charged. The present invention provides a charging device that performs rapid charging while detecting each of the terminal voltages and controlling the charging current according to these detected values.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention includes a first temperature detection section that detects the internal temperature of the battery, a voltage detection section that detects the terminal voltage of the battery, and a first temperature detection section that detects the terminal voltage of the battery. a calculation unit that converts the temperature data from the temperature detection unit from analog to digital at predetermined time intervals, compares the calculated value with the first temperature data of the stored settings, and outputs a signal in the case of failure; and a current control section that switches the quick charging current to the supplementary charging current according to a signal from the calculation section, and the calculation section switches the current to the first temperature detection section after a set time has elapsed after outputting the signal. When the detected temperature data is smaller than the second temperature data set, the voltage data from the voltage detection section and the temperature data from the first temperature detection section are converted from analog to digital and calculated, and the calculated value of the voltage data is calculated. is less than a preset voltage value defined for each calculated value of the second temperature data, the signal output from the calculation unit is stopped, and based on the stop of this signal output, the current control unit switches to the quick charging current. The present invention provides a charging device configured as follows.

[Function] With the above configuration, when charging is performed using the charging device of the present invention, the charging current is controlled according to the temperature rise of the battery, the ambient temperature, the terminal voltage of the battery, etc., so that the charging current is controlled within the required time. The battery can be fully charged automatically.

[Example] Hereinafter, an example of the charging device according to the present invention will be described in detail based on the drawings.

FIG. 1 is a circuit diagram showing an embodiment of a charging device according to the present invention. In the figure, 1 is a battery section, 2 is a charging section, and the battery section 1 is charged by the charging section 2. 3 is a battery, which is a secondary battery such as a nickel-cadmium battery. TI is a first temperature sensing element, and T2 is a second temperature sensing element, both of which are composed of, for example, a thermistor, whose impedance characteristics change with temperature changes. The impedance of the first temperature sensing element TI changes depending on the change in the internal temperature of the battery 3, and the voltage VCC is divided by the resistor R1 and the impedance of the first temperature sensing element TI, and this divided value is used as the impedance of the battery 3. It is input to the analog input port ANI of the calculation unit 4 as internal temperature data. The impedance of the second temperature sensing element T2 changes depending on changes in the ambient temperature, and the voltage Vcc is divided by the resistor R2 and the impedance of the second temperature sensing element T2, and this divided value is used as the data of the surrounding temperature. The signal is inputted to the analog input port AN2 of the calculation unit 4 as follows.

4 is a calculation section, which contains programs for calculation, setting data,
Alternatively, it has RAM (random access memory) for storing calculation data, etc., and has an analog input port ANI.
, , AN2, 8N3 input ports are converted into digital signals by an analog-to-digital converter (A/D converter) (not shown), and the output capacitors are calculated according to the calculated values. -) From PI rHtJ or
Output rLoJ signal.

Ql is a PNP type transistor, which inputs current from the power supply Vdd from its emitter, and when transistor Q2, which will be described later, is off, the collector current determined by the bias of resistors R5 and R6 is controlled by the resistor! ? 7. Input to battery 3 via diode D. R7 is a resistor that limits the collector current of transistor Ql. D is a diode that prevents current from flowing backward from the battery 3 to the charging section 2.

Q2 is an NPN type transistor whose emitter is grounded, and when the "old" signal is output from the output port PI of the calculation section 4, this signal is input to the base and turned on.

By turning on this transistor Q2, the transistor Q1
The base is substantially grounded through the resistor R8, and the collector current is approximately limited by the resistor R7.

Next, the operation of the charging device of the present invention will be explained. The calculation unit 4 performs calculations by A/D converting the voltages input to each analog input port at predetermined time intervals, for example, every minute, by counting internal clock signals or the like. In addition, preset data, calculated data, etc. are stored in a built-in RAM or the like.

To charge the battery 3, first, rapid charging is started when the signal output from the output port P1 of the calculation unit 4 is "old". The charging current is supplied from the power supply Vdd through the transistor Q1, the resistor R7, and the diode D. When the signal output of the output port PI of the calculation unit 4 is rHtJ, the transistor Q2
This r on the base of! "H" signal is input and transistor Q
2 is turned on, and as a result, transistor R1 conducts with its base substantially grounded through resistor R8 and transistor Q2, and the collector current of transistor Q1 is approximately equal to resistor R7.
The current value is limited by This current is
This is a current for rapidly charging the current, and is set to, for example, 2C (twice the rated charging current) by the resistance value of R7.

Also, the signal output from the output port P1 of the calculation unit 4 is rL
o'', the base potential of the transistor Q2 becomes zero due to the rLoj signal and the transistor Q2 is turned off, and the resistor R8 is substantially disconnected from the transistor Q1. As a result, the collector current of the transistor Q2 is the same as that of the resistor R5 and the resistor R6. The current is determined by the base bias voltage given by . This current is a current for replenishing and charging the battery 3, and is, for example, 0. IC (0.1 times the charging rated current) by resistor R5 and resistor R6
Set the base bias voltage of 1.

The internal temperature of the battery 3 increases due to chemical changes that occur inside the battery due to charging. Due to this internal temperature rise, the impedance of the first temperature sensing element T1 in the battery section 1 changes. For example, when a thermistor is used as the temperature sensing element, the impedance of the thermistor decreases as the temperature inside the battery increases.

Therefore, the voltage Vcc is connected to the resistor R4 and this first temperature sensing element T.
Analog input port ANI of calculation unit 4 divided by
The voltage value input to will decrease. The calculation unit 4 performs an A/D conversion on this input voltage at predetermined intervals, for example, every minute, and calculates the calculated value, which is set and stored in advance in a RAM or the like, for example, the maximum allowable internal temperature of the battery. If the temperature is 60℃, then this 6
Data corresponding to 0℃ and when one failure, output boat PI
Outputs the rLoJ signal. Transistor Q2, which receives this rLoJ signal at its base, turns off, so that resistor R8 is substantially disconnected from transistor 01. As a result, the collector current of transistor Q1 is reduced when the base is biased by resistor R5 and resistor R6. current,
That is, the current is switched to supplementary charging current.

Even after the charging current is switched to supplementary charging, the calculation unit 4 continues to calculate the temperature data input to the analog input capo (ANI), and the calculated values are set and stored in RAM etc. in advance. For example, 45°C, which is 15°C lower than the above 60°C.
The voltage data from the voltage detection unit input to the analog input port AN3 is A/D converted and calculated when the data corresponding to the internal temperature of the battery is 45°C or below. It is set in RAM etc. as the value for the terminal voltage at full charge at the temperature.
For example, if the voltage is below 1.44 volts, the output port PI outputs the old j signal and switches the charging current from the supplementary charging current to the quick charging current. In addition, the above setting of 45°C is
This is the internal temperature of the battery that allows safe rapid charging and can be set arbitrarily. Incidentally, the battery terminal voltage when the battery is fully charged is, for example, 1.62 volts at 10°C and 1.55 volts at 20°C in the case of a nickel-cadmium battery element.
volts, such as 1.44 volts at 45°C.

If the calculated value of the voltage data indicates that the battery 3 is fully charged, the calculation unit 4 continues to output the rLoJ signal until charging is terminated by turning off the power, etc., and the device performs supplementary charging. The LoJ signal is reset when the power is turned off, etc., and the next time charging is performed, it becomes the rHIJ signal, and rapid charging is performed.

Further, the calculation unit 4 temporarily holds in a RAM or the like the calculated value of the temperature data inside the battery 3 by the first temperature sensing element TI, which is calculated by A/D conversion at predetermined time intervals. This once held data is A/D converted and calculated after a predetermined period of time, for example, 1 minute, and the difference between the held data and the held data is stored in advance in a RAM or the like. , if the limit of temperature rise per minute is +3℃, then
It is compared with this data indicating +3°C, and when they match, the rLoJ signal is output from the output port P1. Transistor Q2 receives this rLoj signal and turns off, so that the collector current of transistor Q1 switches to a supplementary charging current determined by the base bias voltage provided by resistor R5 and resistor R6. Even after the charging current is switched to supplementary charging, the calculation unit 4 continues to calculate the temperature data input to the analog input port ANI, and calculates the difference between the calculated data and the data held in RAM, etc. , for example, -1, which is set and stored in RAM etc. in advance.
"C" is compared, and when the result is -, the voltage data from the voltage detection section input to the analog input port AN3 is A/D converted and calculated, and the calculated value is the full value at the internal temperature of the battery at that time. The terminal voltage during charging, for example,
If it is 1.55 volts or less at 20℃, the output boat Pl
Outputs the "old" signal and switches the charging current from supplementary charging current to fast charging current.

Note that -l''C in the above setting is the internal temperature of the battery at which the internal temperature of the battery rapidly decreases and can be quickly charged again, but this data can be set arbitrarily.

If the calculated value of the voltage data indicates that the battery 3 is fully charged, the calculation unit 4 continues to output the jLoJ signal until charging is terminated by turning off the power, etc., and the device performs supplementary charging. The signal is reset when the power is turned off, etc., and the next time charging is performed, it will be the old J signal and rapid charging will be performed.

Furthermore, the impedance of the second temperature sensing element T2 of the charging section 2 changes depending on the surrounding room temperature. Therefore, the voltage Vcc
The input voltage to the analog input port AN2 of the arithmetic unit 4, which is divided by the resistor R2 and the second temperature sensing element ↑2, changes in accordance with changes in the room temperature. The calculation unit 4 calculates the input voltage to the analog input port AN2 and the battery 3 by the first temperature sensing element T1 input to the analog input port ANI.
The internal temperature data of the battery are A/D converted and calculated at predetermined time intervals, for example, every minute, and the difference between the calculated values is determined by the internal temperature data stored in advance in RAM, etc. If the limit value for internal temperature rise is 25°C, compare it with the data showing 25°C, and if they match, output from output boat P1.
Outputs rLol signal. Transistor Q2 is connected to this rL
Input oJ signal to turn off, as a result, transistor Q
The collector current of 1 is switched to a supplementary charging current determined by the base bias voltage provided by resistor R5 and resistor R6. Even after the charging current is switched to the supplementary charging current, the calculation unit 4 continues to calculate the temperature data input to the analog input port ANI and the analog input port N2, and the difference between the calculated values is stored in advance in the RAM. For example, compare it with the data indicating 15°C, stored in The value is the internal temperature of the battery, for example, the terminal voltage at full charge at 20°C! , if it is less than 55 volts, outputs an "old" signal from the output capo-PI and switches the charging current from the supplementary charging current to the quick charging current. Note that the above-mentioned setting of 15° C. can be arbitrarily set based on the difference between the internal temperature of the battery that can be rapidly charged again and the room temperature.

If the calculated value of the voltage data indicates that the battery 3 is fully charged, the calculation unit 4 continues to output the rLoJ signal until charging is terminated by turning off the power, etc., and the device performs supplementary charging. The signal is reset when the power is turned off, etc., and the next time charging is performed, it becomes the "old" signal and the device performs rapid charging.

[Effects of the Invention] As explained above, in the charging device according to the present invention, the internal temperature of the battery during charging, the difference between the internal temperature and the surrounding room temperature, or the internal temperature rise of the battery per unit time, etc. While detecting, fast charging is performed until these detected values reach the preset value.Furthermore, after the quick charging is finished once, the terminal voltage of the battery is detected after the set time, and if it is less than the full charging voltage. This device performs quick charging again, and if you use this charging device to charge the battery, the battery will be fully charged quickly, and after being fully charged, it will automatically switch to replenishment charging, so it will not be overcharged and the battery will remain intact. To shorten the lifespan of <<
This eliminates the conventional dissatisfaction caused by insufficient charging or overcharging.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an embodiment of a charging device according to the present invention. In the figure, 1 is a battery section, 2 is a charging section, 3 is a battery, 4 is a calculation section, T1, T2 are temperature sensing elements, Ql, R2 are transistors,
D is a diode, R1 to R8 are resistors, and Vdd is a charging power source. Figure 1 Patent applicant Fujitsu General Ltd.

Claims (3)

[Claims] (1) a first temperature detection section that detects the internal temperature of the battery;
Temperature data from a voltage detection unit that detects the terminal voltage of the battery and a first temperature detection unit is converted from analog to digital at predetermined time intervals and calculated, and the calculated values are stored and set as first temperature data. and a current control section that switches the quick charging current to the supplementary charging current based on the signal from the calculation section, and after outputting the signal, the calculation section After time has elapsed, when the temperature data detected by the first temperature detection section is smaller than the second temperature data set, the voltage data from the voltage detection section and the temperature data of the first temperature detection section are converted into analog data. - Digitally converted and calculated, and when the calculated value of the voltage data is less than the voltage value set for each calculated value of the second temperature data, the signal output from the calculation unit is stopped, and this signal output is stopped. A charging device characterized in that the current control unit switches to a quick charging current based on the current control unit. (2) a first temperature detection section that detects the internal temperature of the battery;
The temperature data from the voltage detection unit that detects the terminal voltage of the battery and the first temperature detection unit is converted from analog to digital at predetermined time intervals, and this calculated value is held and the temperature data is calculated from the first temperature detection unit after a predetermined time. Calculates the calculated value of the temperature data from the temperature detection section with the held calculated value, compares the calculated result with the first data of the stored setting, and outputs a signal when the calculated result exceeds the first data. It consists of a calculation unit that outputs the output, and a current control unit that switches the quick charging current to the supplementary charging current based on the signal from the calculation unit, and the calculation unit, after outputting the signal,
After the set time has elapsed, the calculated value of the temperature data detected by the first temperature detection section is calculated with the held calculated value, and when the calculated result is smaller than the second set data,
A setting in which the voltage data from the voltage detection section and the temperature data from the first temperature detection section are respectively analog-digitally converted and calculated, and the calculated value of the voltage data is specified for each calculated value of the first temperature data. A charging device characterized in that the signal output from the arithmetic unit is stopped when the voltage value is below the voltage value, and the current control unit switches to the quick charging current based on the stop of the signal output. (3) a first temperature detection section that detects the internal temperature of the battery;
A second temperature detection section that detects the temperature around the battery, a voltage detection section that detects the terminal voltage of the battery, and a second temperature detection section that detects the first temperature data from the first temperature detection section and the second temperature detection section. Second
Analog-to-digital conversion is performed on each of the temperature data at predetermined time intervals, and the set third temperature data is added to the calculated value of the second temperature data. It consists of a calculation unit that outputs a signal when the calculation value of the data matches, and a current control unit that switches the quick charging current to the supplementary charging current based on the signal from the calculation unit, and after outputting the signal, the calculation unit After the set time has elapsed, the first temperature data detected by the first temperature detection section is calculated by adding the set fourth temperature data to the second temperature data, and from this added temperature data. When the voltage data is small, the voltage data from the voltage detection unit and the first temperature data from the first temperature detection unit are converted from analog to digital and calculated, and the calculated value of the voltage data is the calculated value of the first temperature data. A charging device characterized in that the signal output from the arithmetic unit is stopped when the voltage is below a predetermined voltage value, and the current control unit switches to a quick charging current based on the stop of the signal output.