POWER SYSTEM AND SET BATTERY CHARGING METHOD

• US 20100052621A1
• Filed: 10/01/2007
• Published: 03/04/2010
• Est. Priority Date: 04/12/2007
• Status: Abandoned Application

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Suzuki, Kohei, Aoki, Mamoru, Sugiyama, Shigeyuki
• Application Number:
  US12/595,772
• Publication Number:
  US 20100052621A1
• Time in Patent Office: Days
• US Class Current: 320/137
• CPC Class Codes: H01M 10/0525 Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• CPC Class Codes: H01M 10/30 Nickel accumulators H01M10/34 takes precedence
• CPC Class Codes: H01M 10/345 Gastight metal hydride accumulators
• CPC Class Codes: H01M 10/441 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H01M 16/00 Structural combinations of different types of electrochemical generators
• CPC Class Codes: H01M 4/525 of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• CPC Class Codes: H02J 7/0013 acting upon several batteries simultaneously or sequentially H02J7/1423 takes precedence
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

This invention relates to a power system comprising secondary batteries and a method of charging a set battery, and more specifically relates to technology which prevents degradation of a set battery which is a power source, even when using a simple constant-voltage charger. An object of this invention is to provide a power system and a charging method which, when using a constant voltage to charge secondary batteries having a higher energy density per unit weight than lead storage batteries, can reduce concerns of deformation of the secondary batteries due to overcharging, and improve safety. According to this invention, in a power system including a set battery in which a plurality of cells are connected in series, and a constant-voltage charger which applies a constant rated charging voltage V_C to charge the set battery, and in a set battery charging method, the total voltage Vx which is the total of the average discharge voltages of the plurality of cells and the rated charging voltage V_C are set so as to satisfy the relation 0.98 Vx≦V_C≦1.15 Vx.

Claims

1. A power system, comprising:

a set battery, in which a plurality of cells are connected in series; and

a constant-voltage charger, which applies a constant rated charging voltage V_C to charge said set battery,

and wherein the total voltage Vx which is the total of the average discharge voltages of said plurality of cells, and said rated charging voltage V_C are set so as to satisfy the relation 0.98 Vx≦

V_C≦

1.15 Vx.

2. The power system according to claim 1, wherein, in said set battery, n_A cells A with an average discharge voltage V_A are connected in series, and the number n_A of said cells A and said rated charging voltage V_C are set so as to satisfy the relation 0.98 n_AV_A≦

V_C≦

1.15 n_AV_A.

3. The power system according to claim 1, wherein the nominal voltage of cells is used as said average discharge voltage.

4. The power system according to claim 1, wherein at least one among nickel hydrogen storage batteries and nickel cadmium storage batteries are used as said cells.

5. The power system according to claim 1, wherein nonaqueous electrolyte secondary batteries are used as said cells.

6. The power system according to claim 5, wherein a lithium complex oxide comprising cobalt is used in an active material of positive electrodes of said nonaqueous electrolyte secondary batteries.

7. The power system according to claim 1, wherein, in said set battery, said n_A cells A, and n_B cells B having an average discharge voltage V_B different from said average discharge voltage V_A, are connected in series, and the number n_A of said cells A, the number n_B of said cells B, and said rated charging voltage V_C are set so as to satisfy the relation 0.98(n_AV_A+n_BV_B)≦

V_C≦

1.15(n_AV_A+n_BV_B).

8. The power system according to claim 7, wherein at least one among nickel hydrogen storage batteries and nickel cadmium storage batteries are used as said cells A.

9. The power system according to claim 7, wherein nonaqueous electrolyte secondary batteries are used as said cells B.

10. The power system according to claim 9, wherein in that a lithium complex oxide comprising cobalt is used in an active material of positive electrodes of said nonaqueous electrolyte secondary batteries.

20. The power system according to claim 8, wherein nonaqueous electrolyte secondary batteries are used as said cells B.

11. A set battery charging method, comprising charging a set battery in which a plurality of cells are connected in series and which has a total voltage Vx that is the total of the average discharge voltages of said plurality of cells, at a constant rated charging voltage V_C which satisfies the relation 0.98 Vx≦

V_C≦

1.15 Vx.

12. The set battery charging method according to claim 11, wherein n_A cells A with an average discharge voltage V_A are connected in series in said set battery, and said set battery is charged at a constant rated charging voltage V_C which satisfies the relation 0.98 n_AV_A≦

V_C≦

1.15 n_AV_A.

13. The set battery charging method according to claim 11, wherein at least one among nickel hydrogen storage batteries and nickel cadmium storage batteries are used as said cells.

14. The set battery charging method according to claim 11, wherein nonaqueous electrolyte secondary batteries are used as said cells.

15. The set battery charging method according to claim 14, wherein a lithium complex oxide comprising cobalt is used in an active material of positive electrodes of said nonaqueous electrolyte secondary batteries.

16. The set battery charging method according to claim 11, wherein, in said set battery, said n_A cells A, and n_B cells B having an average discharge voltage V_B different from said average discharge voltage V_A, are connected in series, and said set battery is charged at a constant rated charging voltage V_C which satisfies the relation 0.98(n_AV_A+n_BV_B)≦

V_C≦

1.15(n_AV_A+n_BV_B).

17. The set battery charging method according to claim 16, wherein at least one among nickel hydrogen storage batteries and nickel cadmium storage batteries are used as said cells A.

18. The set battery charging method according to claim 16, wherein nonaqueous electrolyte secondary batteries are used as said cells B.

19. The set battery charging method according to claim 18, wherein a lithium complex oxide comprising cobalt is used in an active material of positive electrodes of said nonaqueous electrolyte secondary batteries.