The hydrogen bomb has very little to do with FCEV technology, and the only real connection is the word hydrogen. The connection is comparable to how the world around us being consisted of atoms, and the atom bomb having the word atom in it. A better understanding of the technology behind the FCEV and the hydrogen bomb can clear this misunderstanding.
Hydrogen utilized by FCEVs are in the form of hydrogen molecules. Hydrogen gas is pressurized at about 700bar of pressure and stored in a cryogenic tank. To generate torque, gas is fed to a lower-pressure cell and put through an electro-chemical reaction to generate electricity. The safety and reliability of hydrogen fuel tanks concerning their high-pressure storage have been thoroughly engineered and tested, achieving a level of safety similar to that of standard CNG engines, which is the traditional means of engine locomotion.
In the case of the hydrogen bomb, materials are not pressurized hydrogen gas, but deuterium and tritium. Both deuterium and tritium are extremely in their natural states and require tremendous energy to subsist. Even if deuterium and tritium were present, getting the explosive power of a hydrogen bomb will require extreme heat and pressure. That is, over a hundred million degrees at thousands of bars of pressure. Such heat and pressure necessary to detonate a hydrogen bomb actually requires the detonation of a smaller nuclear bomb to “kindle” a fusion reaction. Unlike the hydrogen bomb, FCEVs simply combine oxygen and hydrogen to generate electric power.