Hitachi Maxell Ltd developed a new product to be added to its alkaline battery line "Voltage," which employs the "zero-leakage design" to prevent liquid leak due to over-discharge, etc.
The new product (also called "Voltage") will be released April 1, 2009. The company developed a new zinc alloy to reduce the amount of residual, undischarged zinc, which causes leakage.
According to the results of Hitachi Maxell's survey, over-discharge accounts for 55% of all leakage causes. When a battery is over-discharged, hydrogen gas is rapidly produced inside it, raising the internal pressure. Therefore, to prevent explosion, batteries have a safety valve to discharge hydrogen gas. However, when this valve works, alkaline solution flows out together with the gas.
In order to prevent the leakage, it is required to reduce the amount of undischarged zinc, which cause the generation of hydrogen gas. But it is difficult to use up zinc because zinc oxide surrounds undischarged zinc and blocks electrons.
For the zero-leakage design, Hitachi Maxell made "some improvements to pass electrons even when zinc becomes zinc oxide" and succeeded in reducing the amount of undischarged zinc, said Kenichi Sano, the company's manager of the Planning Department of the Primary Battery Division.
"A surface modification is one of the improvements, but we cannot give further information," he said.
The company calls the new zinc alloy "Microzinc α." By reducing the amount of undischarged zinc, the life of the new battery is extended by 5%, compared with the existing product released in February 2008.
If leakage occurs in the recommended usage period of five years even when the product is properly used, Hitachi Maxell will replace the battery for free and repair/replace the device powered by the battery. The company is "the first in the industry" to provide such a warranty on a battery, it said.
For a start, Hitachi Maxell will release the AA and AAA batteries and aims to sell a total of 10 million pieces a month.