Thin film battery

Abstract

The present invention concerns a flat battery comprising a package formed by a cathode, an anode, and a separator layer sandwiched between the cathode and the anode, a sealing frame extending circumferentially around said package, a first current collector contacting the anode, and a second current collector contacting the cathode. The first and second current collectors each partly cover the sealing frame in a zone being adjacent to the package. According to the invention, the battery further comprises a first polymeric jacket layer being arranged on the first current collector and a second polymeric jacket layer being arranged on the second current collector, said first and second polymeric jacket layers extending circumferentially beyond the current collectors and beyond the sealing frame and being sealed together to form an outer jacket for the battery. Furthermore, the present invention also concerns a method to produce such a battery.

1 . A method for making a flat battery comprising the following steps:
 (a) providing a first polymeric jacket layer,   (b) providing a first current collector and arranging same on said first polymeric sheet,   (c) applying an anode material on said first current collector,   (d) providing a second polymeric sheet,   (e) providing a second current collector made of a metal foil and arranging same on said second polymeric sheet,   (f) providing a sealing frame having an inner contour corresponding substantially to an outer contour of the anode material and the separator on the first current collector,   (g) arranging said frame on one of the current collectors, the frame covering the outer circumference of the current collector,   (h) providing a cathode material and applying same on the second current collector,   (i) providing a separator layer and arranging same on the cathode material,   (j) assembling the flat battery by returning one of the two polymeric jacket layers and arranging it and on the other polymeric jacket layer such that the separator layer is sandwiched between the cathode material and the anode material, the sealing frame then extending circumferentially around the anode material, the cathode material and the separator, and   (k) sealing together said first and second polymeric jacket layer in a zone extending circumferentially beyond the current collectors to form an outer jacket for the battery package, wherein said polymeric jacket layers are also sealed to the frame in a region which lies circumferentially outwards of the current collectors.   
     
     
         2 . The method according to  claim 1 , wherein the sealing frame is arranged on the second current collector before step h is executed. 
     
     
         3 . The method according to  claim 2 , wherein the sealing frame consists of two sealing frame elements, and wherein
 a first frame element is applied on the first current collector before execution of step (c), and   a second frame element is applied on the second current collector before execution of step (h), and   the two frame elements are bonded together to form a frame upon execution of step (k).   
     
     
         4 . The method according to  claim 3 , wherein each sealing frame element, the current collector on which it is arranged and the polymeric jacket layer on which said current collector is arranged) are bonded to each other before the execution of steps (c) and (h), respectively. 
     
     
         5 . The method according to  4 , wherein the sealing frame is coated with a heat-sealable material and is bonded to the current collector on which it is arranged before step (j) is executed.