Lithium reservoir system and method for rechargeable lithium ion batteries

• US 20080003490A1
• Filed: 06/28/2006
• Published: 01/03/2008
• Est. Priority Date: 06/28/2006
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Kojic, Aleksandar, Ahmed, Jasim, Park, Sungbae, Christensen, John F.
• Granted Patent: US 7,726,975 B2
• Time in Patent Office: Days
• US Class Current: 429/61
• CPC Class Codes: H01M 10/0445 Multimode batteries, e.g. containing auxiliary cells or electrodes switchable in parallel or series connections
• 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 10/058 Construction or manufacture
• CPC Class Codes: H01M 10/0585 of accumulators having only flat construction elements, i.e. flat positive electrodes, flat negative electrodes and flat separators
• CPC Class Codes: H01M 10/425 Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing printed circuits H05K1/00
• 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: H01M 2010/4271 Battery management systems including electronic circuits, e.g. control of current or voltage to keep battery in healthy state, cell balancing
• CPC Class Codes: H01M 2220/20 Batteries in motive systems, e.g. vehicle, ship, plane
• CPC Class Codes: H01M 6/5005 Auxiliary electrodes
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

A lithium-ion battery cell includes at least two working electrodes, each including an active material, an inert material, an electrolyte and a current collector, a first separator region arranged between the at least two working electrodes to separate the at least two working electrodes so that none of the working electrodes are electronically connected within the cell, an auxiliary electrode including a lithium reservoir, and a second separator region arranged between the auxiliary electrode and the at least two working electrodes to separate the auxiliary electrode from the working electrodes so that none of the working electrodes is electronically connected to the auxiliary electrode within the cell.

Claims

1. A lithium-ion battery cell, comprising:

at least two working electrodes, each including an active material, an inert material, an electrolyte and a current collector;

a first separator region arranged between the at least two working electrodes to separate the at least two working electrodes so that none of the working electrodes are electronically connected within the cell;

an auxiliary electrode including a lithium reservoir; and

a second separator region arranged between the auxiliary electrode and the at least two working electrodes to separate the auxiliary electrode from the working electrodes so that none of the working electrodes is electronically connected to the auxiliary electrode within the cell.

2. The lithium-ion battery cell of claim 1, wherein the at least two working electrodes include a negative electrode and a positive electrode.

3. The lithium-ion battery cell of claim 1, wherein the first separator region includes an electrolyte with a lithium cation.

4. The lithium-ion battery cell of claim 1, wherein the second separator region includes an electrolyte with a lithium cation.

5. The lithium-ion battery cell of claim 1, wherein the auxiliary electrode is arranged as a reference electrode to estimate an open circuit potential.

6. The lithium-ion battery cell of claim 1, further comprising:

a power supply connected to the current collector of each of the working electrodes to charge the at least two working electrodes;

a first electronic circuit to connect the power supply to the current collector of each working electrode; and

a second electronic circuit to connect the current collector of at least one working electrode to the auxiliary electrode.

7. The lithium-ion battery cell of claim 6, wherein the second electronic circuit includes:

a variable load resistor and a switch connected in series between the current collector and the auxiliary electrode.

8. The lithium-ion battery cell of claim 7, further comprising:

a battery management system to control the variable load resistor and the switch.

9. The lithium-ion battery cell of claim 8, wherein the battery management system is configured to determine a state of charge based on the open circuit potential.

10. The lithium-ion battery cell of claim 8, wherein the battery management system determines at what point to open the second electronic circuit, and a rate of transfer of lithium from the lithium reservoir.

11. A method to replenish lithium-ion capacity of a battery cell, the method comprising:

determining a state of charge of each working electrode; and

transferring lithium from an auxiliary electrode to at least one of the working electrodes based on the determined state of charge,

wherein the battery cell includes;

at least two working electrodes, each including an active material, an inert material, an electrolyte and a current collector,

a first separator region arranged between the at least two working electrodes to separate the at least two working electrodes so that none of the working electrodes are electronically connected within the cell;

the auxiliary electrode including a lithium reservoir; and

a second separator region arranged between the auxiliary electrode and the at least two working electrodes to separate the auxiliary electrode from the working electrodes so that none of the working electrodes is electronically connected to the auxiliary electrode within the cell.

12. The method of claim 11, wherein the transfer of lithium accommodates loss of capacity due to a side reaction.

13. The method of claim 11, wherein the state of charge of each working electrode is determined based on an open circuit potential of each working electrode.

14. The method of claim 13, wherein the open circuit potential of each working electrode is measured directly using the auxiliary electrode as a reference electrode during an equilibrium state of the working electrodes at open circuit.

15. The method of claim 13, wherein the auxiliary electrode is used as a reference electrode to estimate the open circuit potential of each working electrode.

16. The method of claim 15, wherein the open circuit potential of each working electrode is estimated based on a measurement of a potential across the auxiliary electrode and at least one working electrode, and a history of current through the first separator region.

17. The method of claim 11, wherein the state of charge of each working electrode is determined using a battery model and measurements of the full-cell potential and current.

18. The method of claim 11, wherein an electronic circuit connects at least one of the working electrodes to the auxiliary electrode so that when the circuit is closed electrons flow from the auxiliary electrode to the at least one working electrode, and lithium ions flow concurrently through the second separator from the auxiliary electrode to the at least one working electrode.

19. The method of claim 18, further comprising:

monitoring and controlling the transfer of lithium via a battery monitoring system.

20. The method of claim 19, wherein the battery management system determines at what point to open the electronic circuit, and a rate of transfer of lithium from the lithium reservoir.