Lithium-polymer leads the charge
BY PHILIP LORD | 30th Jun 2009
The new battery from LG Chem will also appear in the Kia Forte (Cerato) LPI hybrid – the Avante LPI’s twin – due for release in Korea in August, and then in the much-hyped General Motors electric vehicle, the Chevrolet Volt, in 2010.
The lithium-polymer battery differs from a lithium-ion battery in a key area - the medium used for the battery’s chemical reaction.
Typical lithium-ion battery cells use liquid or gel electrolyte as the conduit by which electrons pass between the anodes and cathodes. One of the by-products of the reaction is heat, and if the cells overheat, the liquid electrolyte can leak and cause a fire.
Lithium-polymer batteries – which Korean company LG Chem has been making for various applications since 2005 – use a dry polymer that is considered more stable and fire-resistant than liquid.
Aside from the safer composition, the changes improve battery life under high-temperature conditions.
The lithium-polymer batteries also hold a more dense charge, meaning that they can be more compact for an equivalent charge, and their self-discharge rate is said to be one-third of nickel-metal hydride batteries, which are used in the Lexus RX450h and the just-superseded Toyota Prius.
Despite GM’s recent financial woes, LG Chem is confident it will ship the first lithium-polymer batteries to GM for the Volt by October 2010.
LG Chem has committed a billion dollars to the new battery technology on a new facility it has just started building at Cheongwon, Korea. The new factory will make lithium-polymer batteries to cater for an EV/hybrid market expected rise from the existing 900,0000 units to 4.6 million units by 2015, when LG Chem hopes to hold 20 per cent of the EV/hybrid battery market.