Samsung SDI Co. and LG Chem Co., South Korea's two major battery makers, are expanding their product portfolios into flexible cells for wearable devices, a move seen to meet increasing global demand for bendable gadgets such as smartwatches.

The two battery-making units of Samsung Group and LG Group said Tuesday they showcased their latest flexible battery lineups at an exhibition held in Seoul.

Samsung SDI unveiled two types of flexible batteries - a stripe and band-type -- that are designed to be applied for use in various wearable devices as necklaces and hair bands, the company said.

The ultra-slim, 0.3mm-thin stripe battery, showcased for the first time, is a next-generation battery made with fiber which enables far greater flexibility than existing bendable cells, the company said.

The band-type battery is designed to be used in smartwatches and is proven to resist over 50,000 bendings and enhance a gadget's capacity by up to 50 percent, it added.

The Samsung unit supplies the bulk of its batteries to its bigger affiliate Samsung Electronics Co., the world's top smartphone maker. Recently there have been market speculations that Samsung's next flagship smartphone, the Galaxy S7, will come in a bendable form. The smartphone is forecast to be released early next year.

LG Chem also put on display a wristband-type battery called "wire battery" that can be folded into half. The company developed a wire-type battery in 2013 for the first time in the world, before it came up with the world's first hexagonal-shape battery in June.

LG Chem said the band-type and hexagonal batteries will likely double the battery capacity for smartwatches.

According to global market tracker Gartner, smartwatches are forecast to account for 40 percent of wrist-wearing devices in the world by 2016, with its global shipments to surpass 100 million in 2020. (Yonhap)