Battery recall should put spotlight on safety

While I write this, Dell and Apple are recalling machines carrying nearly six million Sony Li-ion batteries, in what is considered the greatest recall in industrial history. In the last decade, there have been several recalls of Li-ion batteries. For instance, in 2004, Kyocera Wireless recalled about 1 million batteries used in phones.

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The first commercial version of rechargeable Li-ion batteries was created by Sony in 1991. These batteries have established themselves as ideal for mobile electronics because of their lightweight, high energy density, and a chemistry enabling easy recharge. The Liion cell has been evolving towards advanced energy storage through new technologies. For instance, in February 2005, Nevada-based Altair Nano Technology announced a new kind of Li-ion battery with three times the capacity of existing batteries and fully rechargeable in just six minutes. In March 2005, Toshiba announced a Li-ion battery based on new nano-material technology providing yet superior capacity, charge time, and life. In November 2005, A123 Systems announced a higher power and faster recharging Li-ion cell based on research licensed from MIT. In April 2006, MIT said that it had found a way to form nano-sized wires that can be used to build ultra-thin Li-ion cells with three times the normal energy density. In yet another development, in June 2006, French researchers declared the creation of nano-structured battery electrodes with several times the energy capacity, by weight and volume, of conventional electrodes.

These researches, mainly prodded by consumer demand for more power from smaller and cheaper devices, are leading towards miniaturization. Miniaturization can strain the limits of sensitive components. For instance, the membrane separator, which separates the two electrodes and prevents quick release of energy, is about 20 micrometers thick. If a particle breaches the membrane during manufacturing, it will collide with the electrode, causing the cell to short-circuit. It is such manufacturing contamination that caused the recent recall of Sony batteries.

I think the recall highlights the need for designers to give more importance to safety issues than hitherto when reaching out for consumer satisfaction in designing advanced batteries.