Electric Boats, Hybrids to Benefit from Lithium Battery R&D

By George Backwell at January 15, 2012 02:24
Filed Under: Research & Development

Research and development applied to Lithium-ion batteries (increasingly used as 'energy storage banks' in hybrid marine powered propulsion systems in workboats and leisure craft due to their high energy density) has recently revealed ways to make these batteries safer, cheaper yet with better performance. The relevant research findings come from John Hopkins University Applied Physics Laboratory (APL) and from Japan's National Institute of Advanced Industrial Science and Technology (AIST).

Lithium-ion Battery Bank: Photo US Federal Govt.

Inexpensive Sensor Warns of Lithium-ion Battery Failure

Battery malfunctions (and occasionally fires) occur in all Lithium-ion powered applications ranging in size from the cellphone right through to large hybrid or electrically powered plant and present a safety challenge to manufacturers. Typically such catastrophic failures result from ‘thermal runaway', which occurs when a cell in the battery reaches a critical temperature.
Searching for early-warning of such catastrophic failure, researchers at John Hopkins APL discovered an intrinsic relationship between the internal temperature of Lithium-ion cells and an easily measured electrical parameter of the cell. A small alternating current applied at specific frequencies is modified by the cell in a way that is directly related to the temperature of the critical electromechanical interface between the electrodes and the electrolyte.
Researchers were able to measure the temperature of the layers of the cell where thermal runaway begins by connecting the new sensor at the positive and negative terminals, using power from the battery being monitored; by this means unsafe  thermal conditions could be detected at the critical moment they occur and before the cell vents or sets itself on fire. APL has applied for patents for their invention and is on the lookout for licensing opportunities.

Lithium-ion Batteries – Cost Reduced, Performance Enhanced

The target of the research conducted at AIST in Japan has been to reduce the cost of Lithium-ion batteries (rare-earth metal Lithium is expensive) not only without loss of performance, but also to improve upon it. To achieve this they concentrated their research on replacement of the most expensive Lithium positive electrode (key in determining battery capacity and operating voltage) by other materials – mainly the most inexpensive of all – iron, in combination with titanium-substituted lithium manganese oxide.

The AIST team's research goal is to make available these new materials, proven successful as a cheaper and more effective alternative component of the Lithium battery, to the battery manufacturing industry by 2013 and the cost benefits should begin to filter down the supply chain not too long after that.







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