Li-polymer battery makers emphasize higher energy density, thinner forms

Companies are boosting battery capacity and turning out slimmer units to take greater advantage of demand in the mobile and wearable electronics markets.

China manufacturers of Li-polymer batteries keep up efforts to improve products further, capitalizing on the chemistry's virtual monopoly in the strong mobile electronics and fast-growing wearables markets. They are increasing energy density to bolster battery capacity, while offering thinner units to match the miniaturization requirements in these applications.

The use of LiCoO₂ cathode materials that can be charged at higher than 4.2V is emphasized. Makers such as Shenzhen Juheyuan Science & Technology Co. Ltd and Shenzhen Ex-Energy Technology Co. Ltd employ 4.35V variants in about 10 percent of their Li-polymer batteries for mobile and wearable electronics. The input reached commercialization in China only in 2014.

In the next three to five years, more models will be based on 4.4 and 4.5V LiCoO₂, when such higher-voltage materials come in greater supply locally. So far, only a few domestic cathode providers, including Beijing Easpring, have released 4.4V variants due to limited demand. The majority of Li-polymer batteries from China companies utilize 4.2V LiCoO₂ at present.

In terms of battery profile, popularly used in mobile and wearable devices are those in thicknesses of 2, 3, 4 and 5mm, but makers in China can turn out up to 0.5mm units. YJ Power Group Ltd's selection consists of 2 to 10mm models, with 1mm versions made available when specified. Shenzhen Juheyuan can release as thin as 1.3mm kinds.

For the wearables market, suppliers highlight curved types. YJ Power and Shenzhen Juheyuan have these varieties. The latter's range for this segment includes ultranarrow or 8mm-wide models.

Because of advantages of weight, size and shape over traditional Li-ion kinds, the Li-polymer category accounts for at least 80 percent of lithium batteries used in mobile and wearable electronics products. Its market is expected to continue expanding by more than 10 percent in coming years as shipments of terminal application products, especially the latter type, rise.

Global deliveries of wearable devices will reach 101.9 million units by end-2016, posting 29 percent YoY growth, according to IDC. These are projected to hit 213.6 million units in 2020, which translates to 20 percent CAGR from 2016 to 2020.

In mobile electronics, including smartphones, tablet and notebook PCs, growth will be led by the first, shipments of which will increase 3 percent YoY to reach 1.5 billion units by this year's end, according to IDC. In 2020, the volume will climb to 1.8 billion units, with CAGR at 5 percent in 2015-20.

With this outlook, Shenzhen Ex-Energy anticipates sales of Li-polymer batteries for these devices will increase between 20 and 30 percent by the end of 2016. Shenzhen Shirui is expecting a 20 percent boost, and YJ Power about 10 percent.

Mainland China churns out about 70 percent of the world's Li-ion batteries, including traditional and Li-polymer types. Its production reached 5.6 billion units in 2015, and is nearly 3 billion as of 1H16.

There are about 300 manufacturers offering Li-polymer batteries for mobile and wearable electronics in the mainland, more than 70 percent of which are local businesses. The foreign players include Sony, Samsung SDI and LG Chem, and companies from Taiwan and Hong Kong.

Two-thirds of the suppliers are in Guangdong province and the rest in the provinces of Jiangsu and Fujian, and Tianjin city. The first is responsible for more than 40 percent of the mainland's total output.