Apple files patent for more powerful batteries

Monday, February 21, 2011, 8:58 by Tech Correspondent

Apple has designed a Li-ion battery that provides more energy per unit volume. This means greater energy efficiency in small devices.

Apple’s patent, published by the U.S. Patent and Trademark Office, is titled “Increasing Energy Density in Rechargeable Lithium Battery Cells.” It was discovered by tech blog Apple Insider.

Apple’s new battery will use a constant-current constant-voltage charging technique. The proposed invention is detailed in the patent application that describes charging a battery using a “multi-step constant-current constant-voltage (CC-CV) charging technique.”

apple new battery photo

Photo: Apple's new tech for longer battery life (Courtesy: Apple Insider)

As of now, when the capacity of Li-ion batteries is to be increased, the anode and cathode collectors are increased, resulting in lower energy density by volume. This makes the battery larger, consequently resulting in poor space use. Apple’s new technique will result in a smaller battery per unit of energy (ampere-hour or mAh) produced. Related: Top long battery life laptops in India

Engadget.com describes how Li-ion batteries currently charge very fast initially (constant current, increasing voltage) and then slowly (constant voltage, decreasing current). Apple’s battery will charge with constant-current, constant-voltage. Apple’s new patent was filed in August 2009 and is credited to Rames C. Bhardwaj and Taisup Hwang.

One problem with Apple’s CC-CV charging technique is that the battery’s life can go down depending on difference in temperature, for instance between 45 degrees and 10 degrees. On the other and, the battery’s life will increase if it is at a high state of charge. These factors could be used by Apple to design a more intelligent charging process that can be regulated.

The iPad and MacBook Pro last for about 10 hours on a single charge, but as devices are used for more and more video and audio, this level of efficiency will not remain. Of course, any improvements to current technologies are to buy time until a completely new energy solution is arrived at. Suggested read: Virus improves battery life

In other news, Apple is reported to have adopted Light Peak technology which was originally backed by Intel. Light Peak is meant to be a single solution for all the cables that plug into a computer, including USB drives, scanners, power cords etc. Apple will probably not use the name Light Peak though.

Initially Light Peak will use copper and later fiber-optic cables. It will be much faster than current data transfer technologies allowing 10GB per second simultaneously in both directions, at least in theory.

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