SEALING TOOL KIT FOR THERMAL SEALING OF A BATTERY CELL ENVELOPE AND BATTERY CELL

Abstract

A sealing tool kit for thermally sealing a battery cell envelope, having a first tool which includes a base body which is shape-stable and on which a band-shaped, in particular rectangular, supporting surface is formed, wherein a length of the supporting surface is a multiple of a width of the supporting surface and wherein the supporting surface is provided with a compensating layer of a rubber-elastic material and a resistance heating tape rests on a sealing surface of the compensating layer facing away from the base body, which resistance heating tape is extended along the supporting surface and is fixed at each end to the base body, wherein a first recess and a second recess are formed on the supporting surface, each of which extends over the width of the supporting surface and is arranged at a distance from one another.

Claims

1. A sealing tool kit for thermally sealing a battery cell envelope, having a first tool which comprises a shape-stable base body on which a band-shaped supporting surface is formed, wherein a length of the supporting surface is a multiple of a width of the supporting surface and wherein the supporting surface is provided with a compensating layer of a rubber-elastic material and wherein a resistance heating strip rests on a sealing surface of the compensating layer, which sealing surface faces away from the base body, which heating strip is extended along the supporting surface and is fixed at each end to the base body, wherein a first recess and a second recess are formed on the supporting surface, wherein the first recess and the second recess extend over the width of the supporting surface and wherein the first recess and the second recess are arranged at a distance from one another.

2. The sealing tool kit according to claim 1, wherein a first length of the first recess is greater than the width of the supporting surface and/or wherein a second length of the second recess is greater than the width of the supporting surface.

3. The sealing tool kit according to claim 1, wherein a first base surface of the first recess is flat and wherein a second base surface of the second recess is flat.

4. The sealing tool kit according to claim 3, wherein the supporting surface is flat and wherein the first base surface and the second base surface are aligned in a common plane and/or wherein the first base surface and the second base surface are oriented parallel to the supporting surface.

5. The sealing tool kit according to claim 3, wherein a first layer thickness of the compensating layer, which is applied to the supporting surface, is smaller than or equal to a second layer thickness of the compensating layer which is applied to the first and the second base surface.

6. The sealing tool kit according claim 1, wherein a length of the resistance heating tape is chosen to ensure that the resistance heating tape is to be placed without tension on the supporting surface and the first and second base surfaces.

7. The sealing tool kit according to claim 3, wherein a second tool is arranged opposite the first tool, which second tool is identical with the first tool and which second tool delimits a variable-size sealing gap with the first tool.

8. The sealing tool kit according to claim 7, wherein a minimum distance between the sealing surfaces of the first tool and a sealing surface of the second tool corresponds to a thickness of a sealing seam for two interconnected plastic film layers of a battery cell, and wherein a minimum distance between the base surfaces of the first and second recesses of the opposite arranged first and second tools corresponds to a thickness of a sealing seam in which an electrically conductive electrode is accommodated between two plastic film layers.

9. The sealing tool kit according to claim 1, wherein the base body, the compensating layer and the resistance heating tape are designed for carrying out an impulse sealing process.

10. A battery cell having a battery cell envelope with a first plastic film layer and with a second plastic film layer, the first plastic film layer and the second plastic film layer being welded to form a closed pocket in the region of a sealing seam running around an edge of the battery cell envelope and the sealing seam being penetrated by two electrodes arranged between the first plastic film layer and the second plastic film layer, which electrodes are each formed as electrically conductive strip sections, wherein a first layer thickness of the first plastic film layer and a second layer thickness of the second plastic film layer are constant along the sealing seam.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] An advantageous embodiment of the invention is shown in the drawing. Here shows:

[0020] FIG. 1 a schematic and not to scale side view of a first tool of a sealing tool kit,

[0021] FIG. 2 a schematic and not to scale top view of the first tool of the sealing tool kit,

[0022] FIG. 3 a schematic and not to scale top view of a battery cell and

[0023] FIG. 4 a schematic and non-scale side view of the battery cell received between the first tool and a second tool during the sealing process.

DETAILED DESCRIPTION

[0024] A first tool 2 of a sealing tool kit 1 shown in FIG. 4 is schematically shown in FIG. 1 and comprises a shape-stable base body 3. By way of example, the base body 3 is substantially cuboidal-shaped and comprises a flat first side surface 4 arranged in the plane of representation of FIG. 1. Adjacent to the first side surface 4, the base body 3 has a first end surface 6, a second end surface 7 and a third end surface 8, each of which is flat. Furthermore, the first side face 4 is adjoined by a fourth end face 9, which is also referred to as the support face and which, in contrast to the other end faces 6 to 8, is provided with a profile that can be seen in FIG. 1.

[0025] The profiling of the fourth end face 9 is determined by a first recess 17 and by a second recess 18, which are each formed in the same way and which are introduced into the base body 3 starting from a surface 12 of the fourth end face 9. Both the first recess 17 and the second recess 18 extend, as shown in FIG. 2, over an entire width 11 of the base body 3 and have a flat first base surface 21 or a flat second base surface 22.

[0026] A length 19 of the first recess 17 and a length 20 of the second recess 18 in the direction of a longest edge 10 of the base body 3 is approximately a factor of 2 greater than the width 11 of the base body 3. A first depth 25 of the first recess 17 and a second depth 26 of the second recess 18 are chosen to be the same in a purely exemplary manner, so that the base surfaces 21 and 22 are not only aligned parallel to one another, but are rather arranged in a common, unspecified plane. Exemplarily, it is provided that an inclined surface 13 also referred to as chamfer is provided between the surface 12 and the respective base surfaces 21, 22 in order to prevent excessive angling of the resistance heating tape 14 during the performance of the sealing process.

[0027] As can also be seen from FIG. 1, the resistance heating tape 14 extends from the second end face 7 to the third end face 8 and is secured at each end by a first fastening means 15 to the second end face 7 or at each end by a second fastening means 16 to the third end face 8.

[0028] A compensating layer 23 made of a rubber-elastic material, in particular a silicone material, is applied to the fourth end face 9. The task of this compensating layer 23 is to compensate for annular thickness deviations of the components to be processed together, for example the components of the battery cell 41 described in more detail below. A surface of the compensating layer 23 facing away from the base body 3 is also referred to as the sealing surface 24. Exemplarily, it is provided that a first layer thickness 27 of the compensating layer 23 in the region of the surface 12 as well as a second layer thickness 28 of the compensating layer 23 in the region of the two recesses 17, 18 are identical in each case, so that a compliance or resilience of the first tool 2 is also largely identical over its entire length 10.

[0029] As can be seen from the representation of FIG. 2, the compensating layer 23 completely covers the fourth end face 9, which is rectangular in plain view, while the resistance heating tape 14 runs centrally over the end face 9 and has a smaller width than the base body 3.

[0030] In the illustration of FIG. 3, a battery cell 41 is schematically shown which comprises a pocket-shaped battery cell envelope 42. By way of example, the battery cell envelope 42 is formed from two rectangular plastic film layers 43, 44, which are joined to one another at the edges to form a pressure tight seal and a material bond, thus forming a front side and a rear side of the battery cell envelope 42.

[0031] For this purpose, the two plastic film layers 43, 44 are joined by a circumferential sealing seam 45. This sealing seam 45 comprises, purely by way of example, a total of four sealing seam sections 46, 47, 48 and 49, each designed in a straight line. The two plastic film layers 43, 44 are initially to be joined to one another in the region of the sealing seam sections 46, 47 and 48 with conventional sealing tools, not shown, and the first and second battery plates 51, 52, provided purely by way of example, are then to be inserted into the battery cell envelope 42 through the opening which still exists in the battery cell envelope 42. Subsequently, the pocket-shaped interior of the battery cell envelope 42 can be filled with a liquid or gel electrolyte. Subsequently, the battery cell envelope 42 is sealed by a sealing process with which the fourth sealing seam 49 is produced using the sealing tool kit 1 shown in FIG. 4. In this process, a first electrode connected to the first battery plate 51 and a second electrode 54 connected to the second battery plate 52 penetrate the sealing seam 45 in the region of the fourth sealing seam section 49.

[0032] In the sealing tool kit 1 shown in FIG. 4, in addition to the first tool 2 already described, a second tool 32 is provided which is identical to the first tool 2 and is arranged as a mirror image of the first tool 2. The first tool 2 and the second tool 32 are assigned a drive device, not shown, with which a distance between the first tool 2 and the second tool 32 can be adjusted, whereby a variable-size sealing gap 33 is formed between the first tool 2 and the second tool 32.

[0033] In the illustration of FIG. 4, the position is shown which the first tool 2 assumes with respect to the second tool 32 at the time of carrying out the sealing process for the fourth sealing seam section 49. In this case, a first distance 34 between the surface 12 of the first tool 2 and the surface 12 of the second tool 32 is selected in such a way that the respective compensating layers 23 are elastically deformed and exert the desired force introduction on the first and second plastic film layers 43, 44 resting on one another.

[0034] Furthermore, a second distance 35 between the first base surface 21 of the first tool 2 and the first base surface 21 of the second tool 32 or between the second surface 22 of the first tool 2 and the second base surface 22 of the second tool 32 is dimensioned such that a composite of the two plastic film layers 43, 44, the first electrode 53 or the second electrode 54 and a first electrode sheathing 55 associated with the first electrode 53 and formed from plastic film or an electrode sheathing 56 associated with the second electrode 54 and formed from plastic film is subjected to an identical or at least similar surface pressure as is the case in the region of the opposing surfaces 12.

[0035] The first distance 34 in the sealing gap 33 is dimensioned such that it is slightly smaller than a sum of a first layer thickness of the first plastic film layer 43 and a second layer thickness of the second plastic film layer 44.

[0036] Furthermore, the second distance 35 in the sealing gap 33 is dimensioned such that it is slightly smaller than a sum of the first layer thickness of the first plastic film layer 43, the second layer thickness of the second plastic film layer 44, a thickness of the first or second electrode 53, 54, and a double thickness of the first or second electrode sheath 55, 56.

[0037] Furthermore, a length of the resistance heating tape 14, which according to FIG. 1 rests only loosely on the fourth end face 9, is dimensioned in such a way that the resistance heating tape 14 rests at least almost stress-free on the profiling formed by the surfaces 12 and the recesses 17, 18 and thus the desired uniform surface pressure is ensured over the entire length of the fourth sealing seam section 49.