PTC thermistor and a current limiter device having at least one PTC thermistor

An electronic assembly comprising:

• at least one cooling layer;
• an electrically insulating, thermally conductive polymer matrix;
• a PTC thermistor, the PTC thermistor comprising a resistive track that has a meandering path, the resistive track comprising a first part and a second part, the resistive track embedded in the polymer matrix and spreading horizontally therein such that the polymer matrix adjoins the resistive track on more than two sides, the resistive track thermally connected via the polymer matrix to the at least one cooling layer, wherein the resistive track is folded such that a meandering path of the first part is vertically aligned with a meandering path of the second part in separate horizontal planes;
• an insulation layer between the meandering path of the first part and the meandering path of the second part;
• and
• a metal layer between the insulation layer and at least one of the two meandering paths.

A current limiter device, comprising:

• at least two PTC thermistor assemblies connected in series in a first circuit branch, each PTC thermistor assembly having:
• a cooling layer;
• a resistive track, the resistive track comprising a first main surface and a second main surface, the cooling layer opposite the first main surface;
• an electrically-insulating thermally conductive layer;
• an insulation layer interposed between the first main surface and the cooling layer, wherein the resistive track is connected by the electrically-insulating thermally conductive layer to the insulation layer;
• a pressure compensator, the pressure compensator applying pressure to the second main surface;
• and
• a polymer film interposed between the pressure compensator and the second main surface such that it is in direct contact with the second main surface, the device further comprising:
• at least one varistor in a second circuit branch electrically connected in parallel with the first circuit branch, wherein at least one further electrical resistor is connected in the second circuit branch in series with the at least one varistor wherein
• at least one of the PTC thermistor assemblies has on heating resistance which jumps to less than 100 times its cold resistance, and
• of which at least another one of the PTC thermistor assemblies has on heating resistance which jumps to more than 100 times its cold resistance.

An electronic assembly comprising:

• a PTC thermistor, the PTC thermistor comprising a resistive track;
• a cooling layer;
• an insulation layer disposed between a first surface of the resistive track and the cooling layer;
• a pressure compensator, the pressure compensator applying pressure to a second surface of the resistive track when a force is applied to the pressure compensator, wherein the pressure compensator comprises a metal film that forms a closed shell;
• and
• a flexible, thermally conductive polymer sheet, the polymer sheet interposed between the pressure compensation element and the second main surface such that it is in direct contact with the second main surface.