Battery pack

• US 5,796,238 A
• Filed: 08/01/1994
• Issued: 08/18/1998
• Est. Priority Date: 10/13/1992
• Status: Expired due to Term

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Murayama, Shigeki, Nagai, Tamiji, Hiratsuka, Masaru, Eguchi, Yasuhito
• Primary Examiner(s): Chea, Thorl
• Application Number:
  US08/244,781
• Time in Patent Office: 1,478 Days
• Field of Search: 320/5, 320/21, 320/22, 320/30, 429/22, 429/58
• US Class Current: 320/112
• CPC Class Codes: G01R 31/3648 comprising digital calculation means, e.g. for performing an algorithm
• CPC Class Codes: G01R 31/3842 combining voltage and current measurements
• CPC Class Codes: G01R 31/396 Acquisition or processing of data for testing or for monitoring individual cells or groups of cells within a battery
• CPC Class Codes: H01M 10/48 Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569
• CPC Class Codes: H02J 7/0068 Battery or charger load switching, e.g. concurrent charging and load supply H02J7/0013 takes precedence
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A battery pack (1) is connected to an external circuit (9) and to a power source circuit (10) which is also connected to the external equipment (9). The battery pack (1) is discharged to supply the current to the external equipment (9) or is charged by the current supplied from the power source circuit (10). An analog circuit (12) and a micro-computer (11) within the battery pack (1) detect the on/off state of the external circuit (9) and effect charging in the on-state of the external equipment with the power equal to the total supply power from the power source circuit less the maximum power consumed by the external equipment, while effecting charging during the off-state of the external equipment with the supply power from the power source circuit. The charging/discharging control is performed by the on/off control by the micro-computer (11) of a charging switch (S1), a discharging switch (S2) and a switch (S4).

Claims

1. A battery pack connected to a power source circuit and to external equipment comprising:

a battery unit charged by the power source circuit;

detection means for detecting whether the external equipment is on or off and whether the power source circuit is on or off; and

control means for controlling charging and discharging of the battery unit in response to the on or off status of both the external equipment and the power source circuit.

2. The battery pack as claimed in claim 1, further comprising:

a switch connected between the battery unit and the power source circuit;

means for controlling the switch;

wherein, when said power source circuit is detected to be on, the battery unit is charged with a reduced current.

3. The battery pack as claimed in claim 2, wherein:

the battery unit comprises a plurality of cells;

the battery pack further comprises means for detecting the voltage of the cells; and

the charging of the battery unit with the reduced current continues until the voltage of said cells exceeds a threshold.

4. The battery pack as claimed in claim 2, wherein the switch is a transistor.

5. The battery pack as claimed in claim 1, wherein the battery unit is charged by a constant current which is created by controlling a total current from the power source circuit.

6. The battery pack as claimed in claim 1, wherein a discharge switch is turned on when the charging of the battery unit has ceased.

7. The battery pack as claimed in claim 1, wherein:

the external equipment may be powered by either the battery pack or the power source circuit; and

when the external equipment and said power source circuit have both been on and said power source is turned off, the battery pack immediately and automatically supplies power to the external equipment.

8. The battery pack as claimed in claim 1, further comprising a battery loading terminal to which a voltage is supplied when the battery pack is loaded, wherein an internal circuit of the battery pack is rendered operational or non-operational depending on the voltage at the battery loading terminal.

9. The battery pack as claimed in claim 8, wherein the detection means comprise a voltage divider and an analog circuit for detecting said voltage.

10. The battery pack as claimed in claim 1, wherein the charging of the battery pack is accomplished with a power equal to or less than a total power supplied by the power source circuit minus a maximum power consumed by the external equipment when the detection means detects that both the external equipment and the power source circuit are on.

11. The battery pack as claimed in claim 1, wherein the battery pack goes into a wait mode when both the external equipment and the power source circuit are detected to be off.

12. The battery pack as claimed in claim 1, wherein the battery pack goes into a discharge mode when the external equipment is detected to be on and the power source circuit is detected to be off.

13. The battery pack as claimed in claim 1, wherein the battery pack goes into a background charging mode when both the external equipment and the power source circuit are detected to be on.

14. The battery pack as claimed in claim 1, wherein the battery pack goes into a quick charging mode when the external equipment is detected to be off and the power source circuit is detected to be on.

15. The battery pack as claimed in claim 1, wherein the control means, the detection means and the battery unit are located within a housing of the battery pack.

16. The battery pack as claimed in claim 1, wherein the control means include a micro-computer and a fuse connected between battery unit and the power source circuit which fuse is controlled by the micro-computer.

17. The battery pack as claimed in claim 1, further comprising a protection circuit responsive to the current or voltage of the power source circuit and which comprises an operational amplifier having two input terminals, a resistor connected between the terminals, one terminal connected to the power source circuit and the other terminal connected to the battery unit.

18. The battery pack as claimed in claim 17, wherein the protection circuit further comprises:

a diode with a cathode connected to a positive terminal of the power source circuit; and

a resistor connected in series with the diode and connected to a negative terminal of the power source circuit.

19. The battery pack as claimed in claim 1, wherein the control means further comprise:

a micro-computer; and

a first switch and a second switch connected in series between the battery unit and the power source circuit;

wherein the first and second switches are controlled by the micro-computer to effect charging and discharging of the battery unit.

20. The battery pack as claimed in claim 19, wherein the first and second switches are transistors.

21. The battery pack as claimed in claim 19, wherein said first switch is connected in parallel with a diode and said diode has a cathode connected to the power source circuit and an anode connected to the series connection between the first and second switches.

22. The battery pack as claimed in claim 19, wherein said second switch is connected in parallel with a diode and said diode has a cathode connected to the battery unit and an anode connected to the series connection between the first and second switches.

23. A battery pack connected to a power source circuit and to external equipment comprising:

a battery unit charged by the power source circuit;

detection means for detecting whether the external equipment and the power source circuit are on or off; and

control means for controlling charging and discharging of the battery unit in response to the on or off status of both the external equipment and the power source circuit

wherein;

the battery unit comprises a plurality of cells;

said battery pack comprises means for detecting and comparing voltages of the cells; and

a cell having a maximum voltage is discharged when a voltage difference between the cells exceeds a threshold.

24. A battery pack comprising:

a battery unit which can be charged and discharged;

terminals which allow the battery pack to be connected to a power source circuit and to external equipment;

detection means for detecting whether the power source circuit is on or off and whether the external equipment is on or off;

control means for controlling charging and discharging of the battery unit in response to the detection means; and

a housing for enclosing the battery unit, the detection means and the control means.

25. A battery pack comprising:

a battery unit comprising a plurality of cells which can be charged and discharged;

terminals which allow the battery pack to be connected to a power source circuit and external equipment;

detection means for detecting and comparing the voltages of each of the cells and determining when a voltage difference between the cells exceeds a threshold; and

means for discharging a cell having a voltage higher than other cells when said voltage difference is determined to exceed the threshold.

26. A battery pack as claimed in claim 25, further comprising:

detection means for detecting whether the external equipment is on or off and whether the power source circuit is on or off; and

control means for controlling charging and discharging of the battery unit in response to the on or off status of both the external equipment and the power source circuit.

27. The battery pack as claimed in claim 26, further comprising:

a switch connected between the battery unit and the power source circuit;

means for controlling the switch;

wherein, when said power source circuit is detected to be on, the battery unit is charged with a reduced current.

28. The battery pack as claimed in claim 27, wherein:

the battery unit comprises a plurality of cells;

the battery pack further comprises means for detecting the voltage of the cells; and

the charging of the battery unit with the reduced current continues until the voltage of said cells exceeds a threshold.

29. The battery pack as claimed in claim 27, wherein the switch is a transistor.

30. The battery pack as claimed in claim 26, wherein the battery unit is charged by a constant current which is created by controlling a total current from the power source circuit.

31. The battery pack as claimed in claim 26, wherein a discharge switch is turned on when the charging of the battery unit has ceased.

32. The battery pack as claimed in claim 26, wherein:

the external equipment may be powered by either the battery pack or the power source circuit; and

when the external equipment and said power source circuit have both been on and said power source is turned off, the battery pack immediately and automatically supplies power to the external equipment.

33. The battery pack as claimed in claim 26, further comprising a battery loading terminal to which a voltage is supplied when the battery pack is loaded, wherein an internal circuit of the battery pack is rendered operational or non-operational depending on the voltage at the battery loading terminal.

34. The battery pack as claimed in claim 33, wherein the detection means comprise a voltage divider and an analog circuit for detecting said voltage.

35. The battery pack as claimed in claim 26, wherein the charging of the battery pack i s accomplished with a power equal to or less than a total power supplied by the power source circuit minus a maximum power consumed by the external equipment when the detection means detects that both the external equipment and the power source circuit are on.

36. The battery pack as claimed in claim 26, wherein the battery pack goes into a wait mode when both the external equipment and the power source circuit are detected to be off.

37. The battery pack as claimed in claim 26, wherein the battery pack goes into a discharge mode when the external equipment is detected to be on and the power source circuit is detected to be off.

38. The battery pack as claimed in claim 26, wherein the battery pack goes into a background charging mode when both the external equipment and the power source circuit are detected to be on.

39. The battery pack as claimed in claim 26, wherein the battery pack goes into a quick charging mode when the external equipment is detected to be off and the power source circuit is detected to be on.

40. The battery pack as claimed in claim 26, wherein the control means, the detection means and the battery unit are located within a housing of the battery pack.

41. The battery pack as claimed in claim 26, wherein the control means include a micro-computer and a fuse connected between battery unit and the power source circuit which fuse is controlled by the micro-computer.

42. The battery pack as claimed in claim 26, further comprising a protection circuit responsive to the current or voltage of the power source circuit and which comprises an operational amplifier having two input terminals, a resistor connected between the terminals, one terminal connected to the power source circuit and the other terminal connected to the battery unit.

43. The battery pack as claimed in claim 42, wherein the protection circuit further comprises:

a diode with a cathode connected to a positive terminal of the power source circuit; and

a resistor connected in series with the diode and connected to a negative terminal of the power source circuit.

44. The battery pack as claimed in claim 26, wherein the control means further comprise:

a micro-computer; and

a first switch and a second switch connected in series between the battery unit and the power source circuit;

wherein the first and second switches are controlled by the micro-computer to effect charging and discharging of the battery unit.

45. The battery pack as claimed in claim 44, wherein the first and second switches are transistors.

46. The battery pack as claimed in claim 44, wherein said first switch is connected in parallel with a diode and said diode has a cathode connected to the power source circuit and an anode connected to the series connection between the first and second switches.

47. The battery pack as claimed in claim 44, wherein said second switch is connected in parallel with a diode and said diode has a cathode connected to the battery unit and an anode connected to the series connection between the first and second switches.

48. A battery pack as claimed in claim 26, further comprising a housing for enclosing the battery unit, the detection means and the control means.