A system, method, and computer program product of automatically connecting a mobile communication device to a communication network using a network resource classification database includes detecting a communication network access point using the mobile communication device and reporting network attributes associated with the access point to a resource classification server. The lithium secondary battery has improved cycle life, high rate characteristics, and a high energy density due to an increase of the average discharge voltage at a high rate. Each of the heat storage materials starts to melt if absorbed heat reaches a predetermined temperature, and the heat storage sheet stores heat while being maintained at a fixed temperature, while each of the heat storage materials melts.