Charging apparatus

• US 4,370,606 A
• Filed: 10/10/1980
• Issued: 01/25/1983
• Est. Priority Date: 10/13/1979
• Status: Expired due to Term

• Current Assignee: Asahi Matsushita Electric Works Ltd. (Panasonic Holdings Corporation)
• Original Assignee: Asahi Matsushita Electric Works Ltd. (Panasonic Holdings Corporation)
• Inventors: Furukawa, Kaoru, Kakumoto, Hiromi
• Primary Examiner(s): Pellinen, A. D.
• Application Number:
  US06/196,014
• Time in Patent Office: 837 Days
• Field of Search: 320/22, 320/23, 320/35, 320/36, 320/48, 320/DIG. 2
• US Class Current: 320/141
• CPC Class Codes: H01M 10/443 in response to temperature
• CPC Class Codes: H02J 7/007192 in response to temperature
• CPC Class Codes: H02J 7/007194 of the battery
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A diode is disposed in the vicinity of a rechargeable battery. A current is applied to the diode from a current generating circuit. The current generating circuit comprises a thermistor which is responsive to the ambient temperature, so that a current associated with the ambient temperature is applied from the current generating circuit to the diode. The diode gives rise to a forward voltage drop, which is changeable as a function of the battery temperature. Accordingly, the forward voltage drop across the diode is changeable as a function of the ambient temperature and the battery temperature. The forward voltage drop across the diode is amplified to be used as a reference voltage. On the other hand, the rechargeable battery is supplied with a charging current from a power supply through a thyristor. The gate electrode of the thyristor is connected to receive the reference voltage and the cathode of the thyristor is connected to the battery. Accordingly, the thyristor is turned off if and when the difference between the reference voltage and the battery voltage becomes smaller than the switching voltage of the thyristor.

Claims

1. A charging apparatus for a rechargeable battery, comprising:

charging current providing means for providing a charging current to said rechargeable battery,

first temperature detecting function means responsive to the temperature of said rechargeable battery,

second temperature detecting function means responsive to the ambient temperature,

current generating means responsive to one of said first and second temperature detecting function means for generating a current which is changeable following the change of the temperature as detected,

voltage generating means connected to receive said current generated from said current generating means and responsive to the other of said first and second temperature detecting function means for generating a voltage which is changeable following the change of the temperature detected, and

charge control means responsive to the output voltage of said voltage generating means for controlling said charging current provided from said charging current providing means to said rechargeable battery.

2. A charging apparatus in accordance with claim 1, wherein

said first temperature detecting function means is adapted to exhibit substantially a linear functional relationship with respect to the change of the temperature of said rechargeable battery, and

said second temperature detecting function means is adapted to exhibit a non-linear functional relationship with respect to the change of said ambient temperature.

3. A charging apparatus in accordance with claim 2, wherein

said current generating means is responsive to said first temperature detecting function means for generating said current which is changeable in proportion to the change of the temperature of said rechargeable battery, and

said voltage generating means receives said current which is changeable in proportion to the change of the voltage of said rechargeable battery and is responsive to said second temperature detecting function means to generate said voltage which is changeable in a non-linear manner with respect to the change of said ambient temperature.

4. A charging apparatus in accordance with claim 2, wherein

said current generating means is responsive to said second temperature detecting function means to generate said current which is changeable in a non-linear manner with respect to the change of said ambient temperature, and

said voltage generating means receives said current which is changeable in a non-linear manner with respect to the change of said ambient temperature to generate said voltage which is changeable in a non-linear manner with respect to the change of the temperature of said rechargeable battery.

5. A charging apparatus in accordance with claim 4, wherein

said first temperature detecting function means comprises a diode junction disposed in the vicinity of said rechargeable battery, and

said voltage generating means generates said voltage in proportion to a forward voltage drop across said diode junction, and

said current generating means forms a current path through said diode junction.

6. A charging apparatus in accordance with claim 5, wherein

said second temperature detecting function means comprises a resistive temperature sensitive device, and

said resistive temperature sensitive device is included in said current path of said current generating means.

7. A charging apparatus in accordance with claim 6, wherein

said resistive temperature sensitive device comprises a thermistor.

8. A charging apparatus in accordance with claim 1, wherein

said charge control means comprises

a switching element interposed between said charging current providing means and said rechargeable battery, and

switching element controlling means responsive to the output voltage from said voltage generating means for controlling said switching element.

9. A charging apparatus in accordance with claim 8, which further comprises

reference voltage generating means responsive to the output voltage from said voltage generating means for generating a reference voltage which is proportional to said output voltage from said voltage generating means, and wherein

said switching element controlling means is adapted to control said switching element to be non-conductive when said reference voltage obtained from said reference voltage generating means and the voltage of said rechargeable battery become substantially equal to each other.

10. A charging apparatus in accordance with claim 9, wherein

said switching element comprises a switching element having an input electrode, an output electrode and a control electrode, and

said switching element is connected such that said control electrode receives said reference voltage from said reference voltage generating means, said input electrode is connected to said charging current providing means, and said output electrode is connected to said rechargeable battery, whereby said switching element is rendered non-conductive when the difference between the voltage of said control electrode and the voltage of said output electrode becomes smaller than a predetermined switching voltage.

11. A charging apparatus in accordance with claim 10, wherein

said rechargeable battery has a predetermined voltage at charge completion, and which further comprises

temperature characteristic setting means for setting the temperature characteristic of the total of said voltage at charge completion and said switching voltage and the temperature characteristic of said reference voltage from said reference voltage generating means to be substantially the same.

12. A charging apparatus in accordance with claim 10 or 11, wherein

said switching element having an input, output and control electrodes comprises a silicon controlled rectifier.

13. A charging apparatus in accordance with claim 1, which further comprises

voltage characteristic adjusting means for making said output voltage from said voltage generating means consistent with a predetermined change characteristic.

14. A charging apparatus in accordance with claim 13, wherein

said voltage characteristic adjusting means comprises a resistive element.

15. A charging apparatus in accordance with claim 14, wherein

said resistive element comprises a variable resistor.

16. A charging apparatus in accordance with claim 14, wherein

said resistive element comprises

a plurality of fixed resistors, and

selecting means for selecting said plurality of fixed resistors.

17. A charging apparatus in accordance with claim 1, which further comprises

current characteristic adjusting means for making said current from said current generating means consistent with a predetermined characteristic.

18. A charging apparatus in accordance with claim 17, wherein

said voltage adjusting means comprises a resistive element being inserted in a current path of said voltage generating means.

19. A charging apparatus in accordance with claim 18, wherein

said resistive element comprises a variable resistor.

20. A charging apparatus in accordance with claim 18, wherein

said resistive element comprises

a plurality of fixed resistors, and

selecting means for selecting said plurality of fixed resistors.

21. A charging apparatus for a rechargeable battery, comprising:

charging current providing means for providing a charging current to said rechargeable battery,

switching means having a control electrode interposed between said charging current providing means and said rechargeable battery and responsive to a control voltage being applied to said control electrode for implementing a switching operation,

first temperature detecting function means responsive to the temperature of said rechargeable battery,

second temperature detecting function means responsive to the ambient temperature, and

control voltage generating means responsive to said first and second temperature detecting function means for generating a control voltage which is changeable following the changes of said battery temperature and ambient temperature to said control electrode of said switching means, said control voltage generating means including,

current generating means, and

reference voltage generating means responsive to said current from said current generating means for generating a reference voltage for affording said control voltage.

22. A charging apparatus of a rechargeable battery in accordance with claim 21, wherein

one of said current generating means and said reference voltage generating means is responsive to said first temperature detecting function means, and

the other of said current generating means and said reference voltage generating means is responsive to said second temperature detecting function means.

23. A charging apparatus of a rechargeable battery in accordance with claim 21, wherein

said reference voltage generating means is responsive to both said first and second temperature detecting function means.

24. A charging apparatus of a rechargeable battery in accordance with claim 23, wherein

said current generating means comprises constant current source means for providing a constant current, and

said reference voltage generating means includes,

voltage generating means responsive to said constant current from said constant current source means and responsive to one of said first and second temperature detecting function means for generating a voltage, and

voltage amplifying means for amplifying the output voltage from said voltage generating means and responsive to the other of said first and second temperature detecting function means.

25. A charging apparatus of a rechargeable battery in accordance with claim 21, wherein

said reference voltage generating means comprises

voltage generating means responsive to said current from said current generating means and responsive to one of said first and second temperature detecting function means for generating a voltage,

amplifying means for amplifying the output voltage from said voltage generating means, and

switching element driving means for providing said output voltage from said amplifying means to said control electrode of said switching means as said control voltage and being responsive to the other of said first and second temperature detecting function means.

26. A charging apparatus of a rechargeable battery in accordance with any one of the preceeding claims 21, 22, 23, 24 or 25, wherein

said first temperature detecting function means is adapted to exhibit substantially a linear functional relationship with respect to the temperature change of said rechargeable battery, and

said second temperature detecting function means is adapted to exhibit a non-linear functional relationship with respect to the change of said ambient temperature.

27. A charging apparatus of a rechargeable battery in accordance with claim 26, wherein

said first temperature detecting function means comprises a diode junction thermally coupled to said rechargeable battery.

28. A charging apparatus of a rechargeable battery in accordance with claim 26, wherein

said second temperature detecting function means comprises a resistive temperature sensitive device.

29. A charging apparatus of a rechargeable battery in accordance with claim 28, wherein

said resistive temperature sensitive device comprises a thermistor.