Patent ID: 8586233

Claim:
A portable electronic device having a secondary battery as a power source, comprising: a package, an electronic device body housed in the package, a battery housing portion being a molding housed in the package, which has a battery fitting portion with a predetermined shape for fitting the secondary battery therein, and a covering layer provided on a surface of the battery housing portion on the side of which the secondary battery is fitted, wherein: the secondary battery is a lithium ion secondary battery which includes a silicon-based active material as a negative electrode active material, the covering layer includes a temperature suppression layer for inhibiting a surface temperature rise of the portable electronic device and a block layer for inhibiting discharge of the content from the secondary battery in an overheated state, the block layer is made of a metallic material resistant to a melt of alkali salt including silicon, and when the metallic material is in the form of a 50 μm-thick metallic foil, the foil is resistant to melting by contact with a melt of lithium orthosilicate at a liquid temperature of 1450° C.