The invention relates to a battery (10, 20), which includes many battery cells (1001-1004) for storing electric energy and many sensors (3201-3204) for detecting the temperature measurement values of the battery cells (1001-1004). Each of the battery cells (1001-1004) is provided with one of the sensors (3201-3204), and includes another one sensor (420) for detecting the temperature measurement value of the battery (10, 20) and also includes a monitoring device (510). The monitoring device is connected to the sensors (3201-3204) and the sensor (420), and is used for processing the temperature measurement values of the sensors (3201-3204) and the temperature measurement value of the sensor (420), so the monitoring device (510) performs redundant monitoring of the battery cells (1001-1004). The invention also relates to a battery system, and a transport tool and method.