At the end of 2015, ALSTOM and ADEME created a joint venture dedicated to the development of the TGV of the future which must be 20 % cheaper to buy and to exploit and consume 20 % less energy. In this context, the Aytré site is responsible for designing a new generation of on-board battery. The objective of this battery will be to provide a response to the electricity needs of a TGV in the event of electrical incidents allowing in particular the maintenance of power supply of several major functions. This project will be a real technical challenge: a battery with such capacity has never been embedded in railway equipment. These innovations will be deployed on the order of 100 TGV2020 trainsets