Suppliers emphasize battery quality upgrades

Button-cell battery suppliers in China are complementing their cost advantage with quality improvements and high-end technologies to increase competitiveness, especially against Japan and South Korea counterparts. A number of makers have started adopting stainless steel strips, which are typical among models from Japan. Products with this feature are exported both as a stand-alone unit and as an accessory to other devices.

Besides churning out the popular CR LiMnO2 type, companies have begun releasing LIR LiCoO2/C and ML LiMnO2 batteries to explore the upscale categories. Both are rechargeable and environment-friendly.

More manufacturers are increasing their output of rechargeable versions. Such units now account for 40 percent of Kwanwa Electronic Co.’s total yield.

To addres s homogenei t y and counter the tightening price competition, enterprises are adding value and off ering premium releases. Some provide zinc-air batteries for implants and electronic hearing aids. The products have a high energy density and are eco-friendly. Makers are banking on sustained demand from consumer electronics and accessories to boost slim margins. There are now more than 50 manufacturers in China, a huge jump from fewer than 10 in 2004.

Enterprises have an average monthly output of about 3 million units. Major players such as Naccon Power Technology Co. Ltd and Changzhou Yufeng Electrical Co. Ltd produce up to 30 million.

Midsize vendors, which generally concentrate on Li-polymer and rechargeable button-cell variants, have a monthly yield of 500,000 to 3 million units.

Suppliers have an export ratio of 20 to 50 percent. This figure could be higher, however, because part of the turnout may be shipped abroad indirectly by makers of fi nished devices that bundle the batteries in their packages. The main destinations are Europe, the US, the Middle East and Asia.

Guangdong and Zhejiang provinces are the main hubs, followed by Tianjin and the provinces of Jiangsu and Sichuan.

LiMnO2 dominating

LiMnO2 button-cell batteries make up 80 percent of China’s total output. These “green” products come in slim configurations. PCs, alarm clocks, calculators, digital watches, toys, medical equipment, PDAs, remote controllers, digital cameras and Bluetooth equipment have been driving demand in the last 12 months. At present, CR2016, CR2025 and CR2032 are the best-sellers because of their wide applications.

Disposable models have a nominal and termination voltage of 3 and 2V, and a typical operating current of 0.1 to 0.2mA. They rely on the stable chemical properties of MnO2 as cathode material and the ultrahigh specific energy of lithium metal as anode input. The average volume decreases less than 2 percent per year, which helps extend the service life. Most adopt a semisealed construction.

CR button-cell batteries work in temperatures from -20 to 60 C. They incorporate overheat and short-circuit protection, and have special storage and disposal recommendations.

CR types with a 9.5 to 30mm diameter and a height of 1.2 to 7.7mm are positioned as low-end. These range from $0.074 to $0.44.

Secondary rechargeable LiMnO2 batteries known as ML are less common. Typically quoted from $0.70 to $1.20, these have a nominal voltage of 3V and capacity of 15mAh. The standard charge/discharge current is 0.1mA. The available models include the ML123A, ML621, ML1025 and ML1216.

LIR batteries, which are rechargeable Li-ion varieties, have a higher voltage than disposable ones at 3.6V. Fully charged units can offer up to 4V. The self-discharge rate is within 10 percent per month with no memory effect, but the 45mAh capacity is just a seventh of LiMnO2 disposable versions.

Li-polymer BR or ICS, and alkaline AG are also on offer. The first has a higher working temperature of -30 to 80 C, but is prone to leakage. LIR models are classified as highend, and list from $1.80 to $2.50. The package size is indicated in the standard name. The most-common type and size are CR versions in 2016, 2025, 2032 and 2450. Most units meet CE, RoHS and UL requirements.

Makers ask for an increase in quotation for small-volume orders. This is in light of recent moves by some countries, especially in Europe, to emphasize security approvals in shipping. These include UN 38.3 testing and material safety data sheets, which add $2,000 and $400 per product model, respectively. Such a request in price adjustment, however, is rare because the output volume is usually big enough to distribute the assessment costs.