In accordance with a rapid spread of information relevant apparatuses and communication apparatuses such as a personal computer, a video camera and a portable telephone in recent years, the development of a battery to be used as a power source thereof has been emphasized. The development of a high-output and high-capacity battery for an electric automobile or a hybrid automobile has been advanced also in the automobile industry. A lithium battery has been presently noticed from the viewpoint of a high energy density among various kinds of batteries.
Liquid electrolyte containing a flammable organic solvent is used for a presently commercialized lithium battery, so that the installation of a safety device for restraining temperature rise during a short circuit and the structure for preventing the short circuit are necessary therefor. On the contrary, a lithium battery all-solidified by replacing the liquid electrolyte with a solid electrolyte layer is conceived to intend the simplification of the safety device and be excellent in production cost and productivity for the reason that the flammable organic solvent is not used in the battery.
Also, generation of short circuits caused by dendrite is known in the field of lithium battery. A short circuit is caused when Li deposited in an anode active material layer at the time of charging grows to the direction of a cathode active material layer and thus the anode active material layer and the cathode active material layer physically contact with each other. Several studies have been conducted to prevent a short circuit. For example, in Patent Literature 1, a producing method for a nonaqueous electrolyte battery comprising a step of forming a first solid layer by heating powder of amorphous solid electrolyte material, and a step of forming a second solid layer on the first solid layer by vapor phase method is disclosed. On the other hand, in Patent Literature 2, Li2S—P2S5—LiI based sulfide solid electrolyte material is disclosed.