Calendar and PHEV cycle life aging of high-energy, lithium-ion cells containing blended spinel and layered-oxide cathodes

One hundred seven commercially available, off-the-shelf, 1.2-Ah cells were tested for calendar life and CS cycle- and CD cycle-life using the new USABC PHEV Battery Test Manual. Here, the effects of temperature on calendar life, on CS cycle life, and on CD cycle life; the effects of SOC on calendar life and on CS cycle life; and the effects of rest time on CD cycle life were investigated. The results indicated that the test procedures caused performance decline in the cells in an expected manner, calendar < CS cycling < CD cycling. In some cases, the kinetic law changed with test type, from linear-with-time to about t2. Additionally, temperature was found to stress the cells more than SOC, causing increased changes in performance with increasing temperature.

► The new PHEV tests were evaluated on lithium-ion batteries.
► The capacity loss mechanism depends on temperature and state of charge.
► Resistance increase mechanism depends on temperature and weakly on state of charge.