Nanyang Technological University (NTU) scientists have claimed to have invented a battery component that provides an added layer of protection to prevent short circuits, the leading cause of fires in lithium-ion (Li-ion) batteries. The “anti-short layer” can be easily added inside Li-ion batteries to prevent short circuits during charging.

In 2020, despite an estimated failure rate of less than one in a million, there were 26 power-assisted bicycle fires and 42 cases of personal mobility device fires in Singapore.

A way to prevent battery fires is the need of the hour. The global battery demand is set to grow, with electric vehicles alone requiring up to 2,700 GWh worth of Li-ion batteries a year by 2030, equivalent to some 225 billion mobile phone batteries.

A build-up of lithium deposits known as dendrites that cross the separator between the cathode and anode electrodes of the battery during charging is the primary cause of battery fires. The dendrite builds up, causing a short-circuit leading to an uncontrolled chemical fire.

To prevent this short-circuit from happening, Professor Xu Zhichuan and his research team from the School of Materials Science and Engineering invented an additional “anti-short layer” on the separator, preventing any dendrite from reaching the cathode.

“We know that for a Li-ion battery to work, Li-ions must be able to travel between the positive and negative sides during charge and discharge cycles. However, the transfer of the Li-ions also means the formation of dendrites is inevitable for current commercial Li-ion batteries,” explains Prof Xu, Cluster Director of Energy Storage and Renewables & Low Carbon Generation NTU.

“Instead of preventing the formation of dendrites, we decided to make use of their intrinsic properties by coating an additional layer of conductive material on the separator for these dendrites to connect. Once the dendrites make the connection, it will not be able to continue their growth further, thus preventing them from ever reaching the other side.”

The researchers tested the invention in over 50 cells with different Li-ion battery compositions. They claim no short circuits were detected during the charging phase even when the battery cells were used beyond their lifecycle.

The researchers maintain that the anti-short layer is a common material used in battery manufacturing. The team estimates that the cost after adopting this technology would be around 5% more than the existing production cost of a Li-ion battery. The lower price makes it easy for companies to adopt and scale up the new technology.

The technology is now patent-pending and is being commercialized by NTUitive, NTU’s innovation and enterprise company.

Recently, researchers from the P.G. and Research Department of Chemistry at Christ College in Kerala, India, had claimed to have developed a dendrite-free zinc-iron redox flow battery.

Mercom had reported in April 2020 that Japanese researchers had developed a new electrode material that was intended to make lithium batteries cheaper, more stable, and capable of holding more charge for more extended periods.