Assembled battery, power-supply system and production method of assembled battery

Abstract

An assembled battery comprises mainly multiple non-aqueous secondary cells A and at least one electric device B for voltage detection containing a non-aqueous electrolyte connected to the multiple non-aqueous secondary cells A in series. When a difference in the non-aqueous secondary cell A between a voltage per cell (VA1) at a depth of discharge of 25% and a voltage per cell (VA2) at a depth of discharge of 75% is designated as ΔVA, and a difference in the electric device B between a voltage per cell (VB1) at a depth of discharge equivalent to the depth of discharge of 25% of the non-aqueous secondary cell A and a voltage per cell (VB2) at a depth of discharge equivalent to the depth of discharge of 75% of the non-aqueous secondary cell A is designated as ΔVB, the ΔVB of electric device B is greater than the ΔVA of non-aqueous secondary cell A.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view illustrating an example of the assembled battery according to the present invention.

FIG. 2A is a characteristic graph showing an example of the relationship between depth of discharge and voltage in each cell of the non-aqueous secondary cell A and the electric device B according to the present invention, wherein both the non-aqueous secondary cell A and the electric device B are lithium-ion secondary cells.

FIG. 2B is a characteristic graph showing an example of the relationship between depth of discharge and voltage in each cell of the non-aqueous secondary cell A and the electric device B according to the present invention, wherein both the non-aqueous secondary cell A and the electric device B are lithium-ion secondary cells, and the electric device B is preliminarily charged.

FIG. 2C is a characteristic graph showing an example of the relationship between depth of discharge and voltage in each cell of the non-aqueous secondary cell A and the electric device B according to the present invention, wherein the non-aqueous secondary cell A is a lithium-ion secondary cell and the electric device B is an electric double-layer capacitor.

FIG. 3 is a circuit diagram showing an example of the power-supply system according to the present invention.

FIG. 4 is a characteristic graph showing an example of the relationship between depth of discharge and internal resistance in each cell of the non-aqueous secondary cell A and the electric device D according to the present invention.

Claims

1. An assembled battery, comprising mainly multiple non-aqueous secondary cells A and at least one electric device B for voltage detection containing a non-aqueous electrolyte connected to the multiple non-aqueous secondary cells A in series, wherein, when a difference in the non-aqueous secondary cell A between a voltage per cell (VA1) at a depth of discharge of 25% and a voltage per cell (VA2) at a depth of discharge of 75% is designated as ΔVA, and a difference in the electric device B between a voltage per cell (VB1) at a depth of discharge equivalent to the depth of discharge of 25% of the non-aqueous secondary cell A and a voltage per cell (VB2) at a depth of discharge equivalent to the depth of discharge of 75% of the non-aqueous secondary cell A, as ΔVB, the ΔVB of electric device B is greater than the ΔVA of non-aqueous secondary cell A.

2. The assembled battery according to claim 1, wherein a battery capacity per cell (CB) of the electric device B is greater than a battery capacity per cell (CA) of the non-aqueous secondary cell A.

3. The assembled battery according to claim 1, wherein the electric device B is an electric double-layer capacitor.

4. The assembled battery according to claim 1, wherein the electric device B is a non-aqueous secondary cell.

5. The assembled battery according to claim 4, wherein a negative electrode of the non-aqueous secondary cell A contains a graphite-based carbon material as a negative-electrode active material, and a negative electrode of the electric device B contains at least one material selected from amorphous carbon, alloys and metal oxides as a negative-electrode active material.

6. The assembled battery according to claim 4, wherein a positive electrode of the non-aqueous secondary cell A contains at least one compound selected from iron phosphate compounds and nickel manganese spinel oxides as a positive-electrode active material, and a positive electrode of the electric device B contains a lithium oxide represented by LiMO2 (where M represents at least one metal selected from the group consisting of Ni, Co, Mn, Al, and Mg) as a positive-electrode active material.

7. An assembled battery, comprising mainly multiple non-aqueous secondary cells A and at least one electric device D for internal-resistance detection containing a non-aqueous electrolyte connected to the multiple non-aqueous secondary cells A in series, wherein, when a difference in the non-aqueous secondary cell A between an internal resistance per cell (RA1) at a depth of discharge of 25% and an internal resistance per cell (RA2) at a depth of discharge of 75% is designated as ΔRA, and a difference in the electric device D between an internal resistance per cell (RD1) at a depth of discharge equivalent to the depth of discharge of 25% of the non-aqueous secondary cell A and an internal resistance per cell (RD2) at a depth of discharge equivalent to the depth of discharge of 75% of the non-aqueous secondary cell A, as ΔRD, the ΔRD of electric device D is greater than the ΔRA of non-aqueous secondary cell A.

8. The assembled battery according to claim 7, wherein a battery capacity per cell (CD) of the electric device D is greater than a battery capacity per cell (CA) of the non-aqueous secondary cell A.

9. The assembled battery according to claim 7, wherein the electric device D is a non-aqueous secondary cell.

10. The assembled battery according to claim 9, wherein a negative electrode of the non-aqueous secondary cell A contains a graphite-based carbon material as a negative-electrode active material, and a negative electrode of the electric device D contains at least one material selected from amorphous carbon, alloys and metal oxides as a negative-electrode active material.

11. The assembled battery according to claim 9, wherein a positive electrode of the non-aqueous secondary cell A contains at least one compound selected from iron phosphate compounds and nickel manganese spinel oxides as a positive-electrode active material, and a positive electrode of the electric device D contains a lithium oxide represented by LiMO2 (where M represents at least one metal selected from the group consisting of Ni, Co, Mn, Al, and Mg) as a positive-electrode active material.

12. A power-supply system, comprising the assembled battery according to claim 1.

13. A power-supply system, comprising the assembled battery according to claim 7.

14. A method of producing an assembled battery including mainly multiple non-aqueous secondary cells A, wherein, the multiple non-aqueous secondary cells A and at least one electric device B for voltage detection containing a non-aqueous electrolyte are connected to each other in series;when a difference in the non-aqueous secondary cell A between a voltage per cell (VA1) at a depth of discharge of 25% and a voltage per cell (VA2) at a depth of discharge of 75% is designated as ΔVA, and a difference in the electric device B between a voltage per cell (VB1) at a depth of discharge equivalent to the depth of discharge of 25% of the non-aqueous secondary cell A and a voltage per cell (VB2) at a depth of discharge equivalent to the depth of discharge of 75% of the non-aqueous secondary cell A, as ΔVB, the ΔVB of electric device B is greater than the ΔVA of non-aqueous secondary cell A; anda battery capacity per cell (CB) of the electric device B is greater than a battery capacity per cell (CA) of the non-aqueous secondary cell A, and whereinthe electric device B is subjected to a preliminary charge before the electric device B is connected to the non-aqueous secondary cells A.

15. The method of producing an assembled battery according to claim 14, wherein an amount of the preliminary charge is an electrical quantity not larger than a difference in capacitance between the battery capacity per cell (CB) of the electric device B and the battery capacity per cell (CA) of the non-aqueous secondary cell A.

16. The method of producing an assembled battery according to claim 14, wherein an amount of the preliminary charge is about half of a difference in capacitance between the battery capacity per cell (CB) of the electric device B and the battery capacity per cell (CA) of the non-aqueous secondary cell A.

17. A method of producing an assembled battery including mainly multiple non-aqueous secondary cells A, wherein, the multiple non-aqueous secondary cells A and at least one electric device D for internal-resistance detection containing a non-aqueous electrolyte are connected to each other in series;when a difference in the non-aqueous secondary cell A between a internal resistance per cell (RA1) at a depth of discharge of 25% and a internal resistance per cell (RA2) at a depth of discharge of 75% is designated as ΔRA, and a difference in the electric device B between a internal resistance per cell (RD1) at a depth of discharge equivalent to the depth of discharge of 25% of the non-aqueous secondary cell A and a internal resistance per cell (RD2) at a depth of discharge equivalent to the depth of discharge of 75% of the non-aqueous secondary cell A, as ΔRD, the ΔRD of electric device D is greater than the ΔRA of non-aqueous secondary cell A; anda battery capacity per cell (CD) of the electric device D is greater than a battery capacity per cell (CA) of the non-aqueous secondary cell A, and whereinthe electric device D is subjected to a preliminary charge before the electric device D is connected to the non-aqueous secondary cells A.

18. The method of producing an assembled battery according to claim 17, wherein an amount of the preliminary charge is not larger than a difference in capacitance between the battery capacity per cell (CD) of the electric device D and the battery capacity per cell (CA) of the non-aqueous secondary cell A.

19. The method of producing an assembled battery according to claim 17, wherein an amount of the preliminary charge is about half of a difference in capacitance between the battery capacity per cell (CD) of the electric device D and the battery capacity per cell (CA) of the non-aqueous secondary cell A.