Patent ID: 7589495

Claim:
A battery pack comprising: a battery; communication lines capable of connecting with an electrical device that is attachable to the battery pack; a temperature-sensing element that is connected with one of the communication lines and detects temperature of the battery as a voltage; a switching device that connects with the temperature-sensing element; and a control section connected externally with the switching device to control the switching device; positive terminal and a GND terminal; and a communication section for processing communications with the electrical device (P), the communication section comprising a communication data generation section for constructing data signals that can be received by the electrical device, a communication driver section for executing actual communication with the electrical device via the communication lines, and a memory for storing data including parameters for computing remaining battery capacity, wherein the control section puts the switching device in the open state when the communication lines are being used, and the control section puts the switching device in the closed state to connect the temperature-sensing element with the one communication line so as to output the voltage sensed by the temperature-sensing element to the electrical device via the one communication line when the communication lines are not being used, wherein the temperature-sensing element and the switching device are connected in series between one of the communication lines and the GND terminal, wherein the switching device is connected between the temperature-sensing element and the GND terminal, and wherein the communication lines comprise a data line and a clock line, and the temperature-sensing element is connected to the data line.