Extending cycling lifetime of fast-charging lithium ion batteries
Methods, systems and battery modules are provided, which increase the cycling lifetime of fast charging lithium ion batteries. During the formation process, the charging currents are adjusted to optimize the cell formation, possibly according to the characteristics of the formation process itself, and discharge extents are partial and optimized as well, as is the overall structure of the formation process. During operation, voltage ranges are initially set to be narrow, and are broadened upon battery deterioration to maximize the overall lifetime. Current adjustments are applied in operation as well, with respect to the deteriorating capacity of the battery. Various formation and operation strategies are disclosed, as basis for specific optimizations.
1. A method of extending a cycling lifetime of a lithium ion battery, the method comprising:
initially operating the battery at a narrow range of voltages which is smaller than 1.5V, and
consecutively, upon detection of a specified deterioration in a capacity of the battery, operating the battery at least at one broader range of voltages which is larger than 1.5V,
wherein the narrow range is within 3.1-5.5V and at least one of the broader range(s) is within 1.8-5.5V.
2. The method of claim 1 , wherein the narrow range is within 3.1-4.4V and at least one of the broader range(s) is within 1.8-4.4V.
3. The method of claim 1 , further comprising adjusting charging currents according to estimations of a deteriorating capacity of the battery.
4. The method of claim 3 , further comprising ramping up gradually the charging currents during a first third of a charging duration of the battery.
5. The method of claim 4 , further comprising adjusting the charging current ramping according to estimations of the deteriorating capacity of the battery.
6. The method of claim 1 , further comprising determining the at least one broader range of voltages with respect to an estimated resistance and/or a remaining capacity of the battery.
7. The method of claim 1 , wherein the at least one broader range comprises a plurality of consecutive steps of increasing voltage ranges, between the narrow range and a full operation range of the battery.
8. The method of claim 7 , wherein the narrow range is within 3.1-4.4V, the consecutive ranges are within 3.0-4.4V, 2.8-4.4V, and 2.5-4.4V; and the full range is within 1.8-4.4V.
9. The method of claim 1 , further comprising introducing, intermittently, sets of 1-10 full voltage range cycles configured to redistribute lithium ions in anode material particles of the battery.
10. A fast-charging lithium ion battery unit comprising:
a fast-charging lithium ion battery, comprising at least one of Si, Ge and Sn as anode material, and
a battery management unit configured to modify a range of voltage levels supplied by the battery according to a state of health of the battery, starting from a narrow range and reaching a wider range,
wherein the battery management unit is configured to initially operate the battery at a narrow range of voltages which is smaller than 1.5V, and consecutively, upon detection of a specified deterioration in a capacity of the battery, operating the battery at least at one broader range of voltages which is larger than 1.5V, and
wherein the narrow range is within 3.1-5.5V and at least one of the broader range(s) is within 1.8-5.5V.
11. The fast-charging lithium ion battery unit of claim 10 , wherein the narrow range is within 3.1-4.4V and at least one of the broader range(s) is within 1.8-4.4V.
12. The fast-charging lithium ion battery unit of claim 10 , wherein the battery management unit is further configured to determine the at least one broader range of voltages with respect to an estimated resistance and/or a remaining capacity of the battery.
13. The fast-charging lithium ion battery unit of claim 10 , wherein the battery management unit is further configured to determine the at least one broader range of voltages with respect to an estimated resistance and/or a remaining capacity of the battery.
14. The fast-charging lithium ion battery unit of claim 10 , wherein the at least one broader range comprises a plurality of consecutive steps of increasing voltage ranges, between the narrow range and a full operation range of the battery.
15. The fast-charging lithium ion battery unit of claim 14 , wherein the narrow range is within 3.1-4.4V, the consecutive ranges are within 3.0-4.4V, 2.8-4.4V, and 2.5-4.4V; and the full range is within 1.8-4.4V.
16. The fast-charging lithium ion battery unit of claim 10 , wherein the battery management unit is further configured to adjust charging currents according to estimations of a deteriorating capacity of the battery.
17. The fast-charging lithium ion battery unit of claim 16 , wherein the battery management unit is further configured to ramp up gradually the charging currents during a first third of a charging duration of the battery.
18. The fast-charging lithium ion battery unit of claim 17 , wherein the battery management unit is further configured to adjust the charging current ramping according to estimations of the deteriorating capacity of the battery.