Patent ID: 8394543

Claim:
An electrical power storage system using hydrogen, comprising: a power generation unit generating power using hydrogen and oxidant gas; an electrolysis unit electrolyzing steam to generate hydrogen; a hydrogen storage unit storing hydrogen generated by the electrolysis and supplying the hydrogen to the power generation unit during power generation; a high-temperature heat storage unit storing first heat generated accompanying the power generation and supplying the first heat to the electrolysis unit during the electrolysis; and a low-temperature heat storage unit storing second heat, which is exchanged in the high-temperature heat storage unit and is lower than the temperature of the first heat stored in the high-temperature heat storage unit, and generating with the second heat the steam supplied to the electrolysis unit, wherein at least one of the high-temperature heat storage unit and the low-temperature heat storage unit comprises a plurality of capsules, a heat storage material encapsulated in the plurality of capsules and having a melting point configured to melt when storing heat and to solidify when releasing heat, and a heat storage container accommodating the plurality of capsules and forming flow paths of a heat medium fluid flowing around the plurality of capsules, and wherein each of the capsules has a first ceramic member and a second ceramic member, at least one of which has a container shape, the first ceramic member and the second ceramic member are joined via a joining layer in a state that the heat storage material is inserted therebetween, and the joining layer is provided with a ceramic layer formed by firing a ceramic precursor, a carbon layer formed by firing a carbon adhesive, or a silicon layer formed by firing a silicon brazing material.