Background

Historical Advances in Battery Technology

Advancements in rechargeable batteries have enabled the development of mobile electronic devices, from cordless phones, to laptops, to the ubiquitous mobile phone – which is now essentially a handheld computer and communicator. Previously, major battery capacity innovations have required a change in the chemistry of the battery, which necessitated whole ecosystem changes of manufacturing, power management ICs, charging electronics, and the device platforms in order to take advantage of the new battery chemistry. In the 1960-70s, rechargeable batteries were based on NiCad chemistry, which enabled the growth of cordless phones. NiCad batteries were fairly heavy and also exhibited a “memory effect” which ultimately affected performance.

Enevate enables disruptive improvement in energy density

NiMH batteries started being used in the 1980s, and had advantages of higher capacity and no “memory effect”. The new chemistry batteries required all new charging and management circuits. In the 1990s, batteries based on Li-ion chemistry came on the market. This was a more substantial change compared to the change from NiCad to NiMH because the fundamental voltage of the cell jumped from 1.2V to 3.7V. Li-ion batteries had substantial increases in energy density over NiMH, (40% smaller and lighter) and could be recharged in any condition. Once again, all new charging and power management electronics had to be developed, as well as new battery manufacturing factories. Li-ion batteries historically have shown an average of 5% per year improvement in energy density, but with little increase in the last few years.

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