Honda Motor Co. and Nissan Motor Co. are developing next-generation electric vehicle batteries that can reduce charging time and expand the range of green cars, sources close to the matter said Thursday.

The two Japanese automakers are separately planning to produce solid-state batteries, which are considered safer with a lower risk of battery leakage and can be charged in a few minutes — compared with more common lithium ion EV batteries, which usually take more than 10 minutes — the sources said.

With their greater capacity such EV batteries will also increase the mileage per charge, they added.

The solid-state battery "has a huge potential" to become the key to boosting EVs, a Honda executive said.

The carmaker is considering tying up with other companies to develop car batteries, but technical hurdles remain for mass production.

The moves come as competition to produce emission-free cars and EV technologies continues to intensify across the globe amid tighter regulations. Japan's leading automaker, Toyota Motor Corp., is developing an EV battery as well.

Last week, Toyota said it is in talks with Panasonic Corp. to team up on developing and producing lithium ion and next-generation solid-state batteries.

Toyota currently has a team of 200 people working on developing a solid-state battery, with an eye to installing it in cars in the first half of the 2020s, while Nissan aims to put its next-generation battery into use in the latter half of the 2020s. Honda has not specified a date.