System and method for heating back-up battery of motor vehicle emergency radio communication device when temperature is below a limit value

摘要

An emergency system for a motor vehicle having an onboard power supply system which triggers in an emergency a radio emergency call regardless of the state of the on-board power supply system of the motor vehicle, including a radio communication device that triggers the emergency call, a back-up battery including one or more electrochemical cells that supply the radio communication device with electric energy, and an electric heating device supplied with power by the on-board power supply system with which the back-up battery can be heated when its temperature is below or drops below a lower limit value, wherein the electric heating device is a heating foil including heating resistors laminated between electrically insulating foils and having a thickness <2 mm, and the heating foil is arranged in a substantially planar, two-dimensional contact to the electrochemical cell(s) of the battery.

主权项

1. An emergency system for a motor vehicle having an on-board power supply system which triggers in an emergency a radio emergency call regardless of a state of the on-board power supply system of the motor vehicle, comprising:
a radio communication device that triggers the emergency call, a back-up battery comprising one or more electrochemical cells that supply the radio communication device with electric energy, the back-up battery being dimensioned such that, in a charged state at a temperature of minus 40° C., the back-up battery is not capable of providing a voltage sufficient to operate the radio communication device, and an electric heating device supplied with power by the on-board power supply system with which the back-up battery is configured to be heated when its temperature is below or drops below a lower limit value, wherein the heating device 1) is a heating foil comprising heating resistors laminated between electrically insulating foils and having a thickness <2mm, and the heating foil is arranged in a substantially planar, two-dimensional contact to the one or more electrochemical cells of the back-up battery, and 2) comprises a heating resistor whose specific electric resistance ρ [Ωm] increases by at least 1 decimal power when temperature increases from minus 40° C. to plus 20° C. and is arranged to regulate the heating device.