Fast charging method and apparatus for secondary cells
US6020720A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 15, 1998 |
| Grant date | Feb 1, 2000 |
| Priority date | — |
| Expiry date | Oct 15, 2018 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02E60/10
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A fast charging method and apparatus for secondary cells, especially for lithium ion cells. The charging process has two charging phases. In the first charging phase, a constant current is supplied to the secondary cell from a charging apparatus whilst monitoring the output voltage of the charging apparatus. The first phase terminates when the output voltage of the charging apparatus reaches a predetermined maximum voltage (e.g., 4.2 volt for a lithium ion cell). Then, in the second charging phase, the output voltage of the charging apparatus being monitored and constant current pulses of fixed duration (e.g., 10 seconds) are supplied to the secondary cell in a manner such that the duration of intervals between such constant current pulses is controlled to maintain an average output voltage of the charging apparatus at a predetermined average voltage (e.g., 4.2 volt for a lithium ion cell). The charging is terminated when the duty cycle of the pulses falls below a predetermined value.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.