Altech Batteries (ASX:ATC) said stress testing of individual cells of its Cerenergy batteries confirmed the safety and operational robustness of the technology, according to a Thursday Australian bourse filing.

The company's joint venture partner Fraunhofer Ikts conducted the tests, which included long-term cycling, an over-discharge test, an over-charge test, critical operating temperatures, and full thermal cycle tests, the filing said.

Altech Batteries' shares fell almost 5% in recent trading on Thursday.