Lithium-ion secondary battery system

1. A lithium-ion secondary battery system comprising:

a lithium-ion secondary battery having a cathode, an anode including carbon, and a non-aqueous electrolyte [doesn't teach this];

a charge/discharge circuit for putting the lithium-ion secondary battery on charge according to a charge control parameter; and

an arithmetic processing section for controlling the charge/discharge circuit,

wherein the arithmetic processing section obtains battery characteristics of the lithium-ion secondary battery, changes a value of the charge control parameter when the arithmetic processing section determines that the battery characteristics satisfies a condition for changing the charge control parameter, and restores the value of the charge control parameter to the value before the change when the charge for the lithium-ion secondary battery is finished,

wherein the arithmetic processing section obtains an integrated value of a discharge capacity and a ratio of an amount of voltage change and the discharge capacity as the battery characteristics, changes the value of the charge control parameter when the arithmetic processing section determines that the ratio and the integrated value satisfy respective conditions for changing the charge control parameter, and restores the value of the charge control parameter to the value before the change when the charge for the lithium-ion secondary battery is finished.

2. The lithium-ion secondary battery system according to claim 1 , wherein the arithmetic processing section increases time or voltage of constant-voltage charge which is the charge control parameter when the arithmetic processing section determines that the ratio and the integrated value satisfy respective conditions for changing the charge control parameter, and restores the time or the voltage of the constant-voltage charge to the value before the change when the charge for the lithium-ion secondary battery is finished.

3. The lithium-ion secondary battery system according to claim 1 , wherein the arithmetic processing section obtains an integrated value of the discharge capacity and a ratio of a width of voltage change and a width of initial voltage change as the battery characteristics, increases time or voltage of constant-voltage charge which is the charge control parameter when the arithmetic processing section determines that the ratio and the integrated value satisfy respective conditions for changing the charge control parameter, and restores the time or the voltage of the constant-voltage charge to the value before the change when the charge for the lithium-ion secondary battery is finished.

4. The lithium-ion secondary battery system according to claim 1 , wherein the arithmetic processing section is detachable.

5. The lithium-ion secondary battery system according to claim 1 , wherein the anode includes a mixture of graphite and non-graphite carbon as an anode active material, and the cathode and the anode have different ratios of an amount of voltage change and a discharge capacity from each other.

6. The lithium-ion secondary battery system according to claim 5 , wherein a charge capacity density per unit weight of the anode active material is 250 to 330 mAh/g when the lithium-ion secondary battery is charged to a rated capacity.

7. A lithium-ion secondary battery system comprising:

a lithium-ion secondary battery having a cathode, an anode including carbon, and a non-aqueous electrolyte;

a charge/discharge circuit for putting the lithium-ion secondary battery on charge according to a charge control parameter; and

an arithmetic processing section for controlling the charge/discharge circuit,

wherein the arithmetic processing section obtains battery characteristics of the lithium-ion secondary battery, changes a value of the charge control parameter when the arithmetic processing section determines that the battery characteristics satisfies a condition for changing the charge control parameter, and restores the value of the charge control parameter to the value before the change when the charge for the lithium-ion secondary battery is finished,

wherein the arithmetic processing section obtains an integrated value of the a discharge capacity and a ratio of an amount of temperature change in time and the discharge capacity as the battery characteristics, increases time or voltage of constant-voltage charge which is the charge control parameter when the arithmetic processing section determines that the ratio and the integrated value satisfy respective conditions for changing the charge control parameter, and restores the time or the voltage of the constant-voltage charge to the value before the change when the charge for the lithium-ion secondary battery is finished.

8. The lithium-ion secondary battery system according to claim 7 , wherein the arithmetic processing section increases time or voltage of constant-voltage charge which is the charge control parameter when the arithmetic processing section determines that the ratio and the integrated value satisfy respective conditions for changing the charge control parameter, and restores the time or the voltage of the constant-voltage charge to the value before the change when the charge for the lithium-ion secondary battery is finished.

9. The lithium-ion secondary battery system according to claim 7 , wherein the arithmetic processing section obtains an integrated value of the discharge capacity and a ratio of a width of voltage change and a width of initial voltage change as the battery characteristics, increases time or voltage of constant-voltage charge which is the charge control parameter when the arithmetic processing section determines that the ratio and the integrated value satisfy respective conditions for changing the charge control parameter, and restores the time or the voltage of the constant-voltage charge to the value before the change when the charge for the lithium-ion secondary battery is finished.

10. The lithium-ion secondary battery system according to claim 7 , wherein the arithmetic processing section is detachable.

11. The lithium-ion secondary battery system according to claim 7 , wherein the anode includes a mixture of graphite and non-graphite carbon as an anode active material, and the cathode and the anode have different ratios of an amount of voltage change and a discharge capacity from each other.

12. The lithium-ion secondary battery system according to claim 11 , wherein a charge capacity density per unit weight of the anode active material is 250 to 330 mAh/g when the lithium-ion secondary battery is charged to a rated capacity.