NOVELTY - The device (1A) has a test stand (3) for setting a rechargeable secondary battery (2) i.e. square shaped lithium ion battery. A pressing member crushes the battery, and a pressurizing device (9) controls a pressing force of the pressing member to the battery, so that the battery is incompletely and partially crushed. Measurement device (13) measures temperature and voltage of the partially crushed battery. The pressing member partially crushes each of a set of identical batteries subjected to testing targets, where the batteries are partially crushed in a sequence according to natural numbers.    USE - Battery testing device for use in a portable device i.e. portable telephone, for measuring the behavior of a rechargeable secondary battery i.e. square shaped battery (claimed) such as lithium ion battery and lithium polymer battery, when damage occurs.    ADVANTAGE - The secondary battery set on the test stand is partially crushed using the pressing member, and the quality of the secondary battery is determined by measuring the temperature of the secondary battery, thus appropriately verifying the battery behavior when the secondary battery is damaged. The device improves performance and safety of the battery such as lithium ion battery, enclosed in the portable telephone. The pressurizing device controls the pressing force by changing a predetermined height from each of the set of secondary batteries, and the measurement device measures the respective temperature of the set of partially crushed secondary batteries, so the pressing force of the pressing member generated by the drop impact can be easily controlled by changing the predetermined height.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a battery testing method.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic diagram illustrating an overview of a battery testing device.    Battery testing device (1A)    Rechargeable secondary battery (2)    Plane portions (2a)    Side face portion (2b)    Test stand (3)    Guide bars (3a)    Round bar (5)    Movable plate (7)    Securing rod (7a)    Pressurizing device (9)    Control circuit (9a)    Drive motor (9b)    Operation unit (9c)    Temperature sensor (11)    Measurement device (13)    Measurement circuit (13a)    Output unit (13b)