Abstract: A heat transfer device with a plate sandwich structure includes at least two flow-duct-covering plates and one flow duct plate unit arranged in between which is formed of one or more superimposed flow duct plates each provided with flow duct breakthroughs. By means of the flow duct breakthroughs in one flow duct plate or by suitably overlapping flow duct breakthroughs of several adjoining flow duct plates, one or more flow paths are formed which extend predominantly in parallel to the plate plane between an inflow point and an outflow point. Such structures, capable of passing through one or more fluids passing through, are produced rather inexpensively and can be used, for example, as a battery cooling element.