How to Ensure Safety of EV or FCV Without Reliable, Helpful Saving Functions Made by ICE

The power train electrification has been remarkably evolving and HEVs or EVs are increasing in world-wide markets. Especially recently, pure electric driving system such as EVs or FCVs without any ICEs are highly desired as better solutions for environmental protection. However, we have to recognize the important role of engine for conventional ICE vehicle. Engine has reliable, helpful saving function on long and steep downhill road. It provides everlasting reliable engine brake. On the contrary, EVs and FCVs do not have engine. Instead of engine brake, regenerative brake is usually utilized for EVs and FCVs. However there remains emergent situation where battery SOC is full on long and steep downhill road driving. Thus, we have to develop emergency brake for those pure electric driving systems. In this paper, the background of this issue is explained in detail and several effective solutions to fix this issue are proposed.