Energizer Triples Zinc Air Battery Run Time By Keith Chan

The downside of these batteries is that they’re not rechargeable, but they’re still smaller than other standard batteries.

Energizer plans to launch a new type of standard battery in the summer of 2010, based on technology invented some 35 years ago. The Energizer Zinc Air, a primary (non-rechargeable) battery solution, uses oxygen from the air as an energy source to generate power. The new batteries provide longer run time, come in a smaller form factor, and are expected to open up a much bigger market for the company.

While other types of primary battery contain two dissimilar materials (anode and cathode), zinc air batteries contain only one; the size of a standard battery of the same volume is therefore significantly reduced. The batteries have a thickness of only 5mm, as compared with the 8mm thickness of the smallest alkaline battery (AAAA), and are available in a new prismatic (rectangular) form factor (see Fig).

The zinc air battery is designed with air access holes that are sealed with a tab, which the consumer removes in order to start using the battery. A major disadvantage, however, is that when the active material is exposed to the environment, the battery’s ability to deliver in the high current range begins to deteriorate. The typical run time of previous-generation zinc air batteries, therefore, was only about one to three months.

Airflow Control

Over the last few years, R&D engineers at Energizer have improved the zinc air technology, and have been able to extend the run times of both alkaline and lithium-ion batteries of similar volumes by as much as three times. "What we have done is, we have figured out how to control the airflow, giving the battery just enough air to support the application, and nothing more," said Jon Eager, director, OEM Marketing, OEM Strategic Alliance Team, Energizer.

But since zinc air batteries use oxygen to generate energy, the environment in which an electronic device is used can also impact the performance of the batteries. For example, when the batteries are used to power a device in a lower temperature environment, the ability to deliver energy may decrease. Designers need therefore to consider the kind of environment a device will be used in, and the way in which the device will be used.

Also, when the batteries are physically exposed to the environment, they might pick up water from humid air, or might dry out due to low humidity. A key area with OEM device designs, therefore, has been the addition of air management to the device to control air access to the battery, so that maximum possible runtime can be achieved.

Eager said so far about 30 OEMs have expressed an interest in the zinc air battery, and the company has design teams working with six of the OEMs to help them design batteries for their devices. These OEMs are making a variety of low-power consumer products, such as wireless keyboards, Bluetooth headsets, remote controls, Flash audio players, penlights, etc. Some of these products are expected to be available on the market in the summer of 2010.

Meanwhile, Energizer also plans to launch new-generation zinc air batteries through major retailers in the summer of 2010, so that consumers can buy products confident in the knowledge that they will be able buy replacement batteries easily. The first model will be the 1.5V PP355 (AAAA volume) battery, which will be available in a new 5mm-thick prismatic package, measuring 32.2 x 14.7 x 4.0mm. The company plans to introduce smaller and larger sizes at a later stage, and eventually to offer an entire family of different-sized products. The retail price of zinc air batteries is expected to be about the same as that of the special lithium batteries.