Nickel metal hydride cells designed for high rate/low temperature performance
US6287724A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 17, 1998 |
| Grant date | Sep 11, 2001 |
| Priority date | — |
| Expiry date | Jul 17, 2018 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02P70/50
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A metal hydride rechargeable cell is provided that discharges during a test discharge at a rate of 8 C to 18 C and a cell temperature of 0.degree. C. where the voltage remains above 0.2 volts during the half of the discharge curve. The cell comprises a negative electrode of hydrogen storage alloy material having a particle size volume distribution whose d(50) value does not exceed 2(2D.sub.h t).sup.1/2, where D.sub.h is the hydrogen diffusion coefficient for the alloy at 0.degree. C. and t is a time period from about 200 to about 450 seconds. A method of manufacturing the cell of the present invention involves an activation protocol comprising at least one formation cycle, a heat treating step, and a cycling step. This method avoids unnecessary processing of the metal alloy material prior to incorporation into the negative electrode.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.