How to make batteries flexible

Coin cells, cylindrical and prismatic batteries are very familiar to us as they are used in mobile phones, laptops, electronic gadgets and also EVs. These batteries are manufactured under mature technology and established facility with a huge number of units per year. However, with the development of wearable devices, batteries with special form factors and features are required with increasing demand, where the bulky, heavy or big batteries cannot provide. One special feature that many wearable devices are in need of is flexibility. Generally, there are two approaches to make flexible batteries.

From flexibility to better performance

When batteries are made very thin, they can be flexible. This approach usually involves new materials/chemistries or new manufacturing methods. Examples include Blue Spark, Enfucell, Flexel, Imprint Energy, STMicroelectronics, ProLogium, etc. Those companies provide batteries with great flexibility, but they normally lag in performance. That is because based on current battery technologies, how much energy can be stored in a battery largely depends on the battery volume and existing energy density. Energy density development is slow and there is no significant technology breakthrough until now. In order to get a battery that can store more energy, the simplest way is to increase the size of the battery. Thin batteries have reduced thickness than ordinary batteries. Therefore, they tend to have less capacity and even less power compared with ordinary batteries with similar footprint. The key to success is to further improve battery technology and have proper product positioning.

From better performance to flexibility

Another approach is to add special features including flexibility to traditional lithium-ion batteries. That can be achieved by altering structural designs and improved materials. For those batteries, they usually have better performance than the first kind, but continuously bending and curving batteries may introduce cracks and damage the batteries, leading to shorter cycle life.

Batteries have been a bottle neck for electric devices, both due to the short lasting hours and their rigid and bulky characteristics. Flexible batteries are the last piece of the wearable technology puzzle. IDTechEx predicts that the thin, flexible and printed battery market will grow to over $400m by 2025, with applications including RFID, smart card, wireless sensor(s)/networks, smart packaging, medical & cosmetic disposable, medical device, interactive media, toys, games, cards, wearable (non-medical), backup power, portable electronics, energy harvesting and others.