Electrochemical energystorage device having a reservoir for an additive

1. An electrochemical energy storage device system, comprising:

an electrochemical energy storage device comprising at least one cell including at least one cathode, at least one anode, and at least one electrolyte, wherein the electrolyte enables a current flow from the anode to the cathode;

a reservoir connected to the electrochemical energy storage device and containing a cover-layer-forming additive;

a control unit for selectively starting or stopping an inflow of the additive into the at least one cell;

wherein the control unit is adapted to control a metering of the cover layer-forming additive into the at least one cell at a predefined point in time;

wherein the control unit is adapted to determine a predefined point in time for metering from a state of health of the electrochemical energy storage device; and

wherein the control unit meters the cover layer-forming additive to restore stabilizing cover layers on the at least one cathode and the at least one anode.

2. The electrochemical energy storage device system as recited in claim 1 , further comprising:

a closing system provided between the cell and the reservoir, wherein the closing system is configured to selectively close or open an inflow channel from the reservoir into the cell.

3. The electrochemical energy storage device system as recited in claim 2 , wherein the closing system is one of a valve or a piezoelectric diaphragm.

4. The electrochemical energy storage device system as recited in claim 3 , wherein each cell of the electrochemical energy storage device is connected to a corresponding dedicated reservoir.

5. The electrochemical energy storage device system as recited in claim 4 , wherein each reservoir is integrated into the corresponding cell.

6. The electrochemical energy storage device system as recited in claim 3 , wherein at least two cells of the electrochemical energy storage device are connected to one shared reservoir, and wherein the closing system is situated within the connection between the shared reservoir and each of the two cells.

7. The electrochemical energy storage device system as recited in claim 6 , wherein all cells of the electrochemical energy storage device are connected to one shared reservoir, and wherein the closing system is situated within the connection between the shared reservoir and each of the cells.

8. The electrochemical energy storage device system as recited in claim 7 , wherein the control unit is adapted to activated each closing system situated within the connection between the shared reservoir and each of the cells.

9. The electrochemical energy storage device system as recited in claim 8 , wherein the control unit is a battery management system.

10. The electrochemical energy storage device system as recited in claim 8 , wherein the additive is one of vinylidene carbonate, 1-fluorobutylene carbonate, ethylene carbonate or alkyl phosphates.

11. The electrochemical energy storage device system as recited in claim 8 , wherein the electrochemical energy storage device is a lithium-ion accumulator.

12. A method for operating an electrochemical energy storage device including at least one cell having at least one cathode, one anode, and one electrolyte which enables a current flow from the anode to the cathode, comprising:

metering a cover layer-forming additive into the at least one cell at a predefined point in time;

wherein the predefined point in time for metering is determined from a state of health of the electrochemical energy storage device; and

wherein the cover layer-forming additive is used to restore stabilizing cover layers on the at least one cathode and the at least one anode.

13. An electrochemical energy storage device system, comprising:

an electrochemical energy storage device comprising at least one cell including at least one cathode, at least one anode, and at least one electrolyte, wherein the electrolyte enables a current flow from the anode to the cathode;

a reservoir connected to the electrochemical energy storage device and containing a cover-layer-forming additive;

a control unit for selectively starting or stopping an inflow of the additive into the at least one cell;

wherein the control unit is adapted to control a metering of the cover layer-forming additive into the at least one cell at a predefined point in time;

wherein the control unit is adapted to determine a predefined point in time for metering from an increase in an internal resistance of the electrochemical energy storage device; and

wherein the control unit meters the cover layer-forming additive to restore stabilizing cover layers on the at least one cathode and the at least one anode.

14. A method for operating an electrochemical energy storage device including at least one cell having at least one cathode, one anode, and one electrolyte which enables a current flow from the anode to the cathode, comprising:

metering a cover layer-forming additive into the at least one cell at a predefined point in time;

wherein the predefined point in time for metering is determined from an increase in an internal resistance of the electrochemical energy storage device; and wherein the cover layer-forming additive is used to restore stabilizing cover layers on the at least one cathode and the at least one anode.