How to Isolate Battery Cells

Abstract

To provide a method for insulating a battery cell, which can be connected to lower material cost and be easily executed.SOLUTION: The present invention is a method for insulating a battery cell (10). The battery cell (10) has a battery casing provided with an electric contact member (12) for electric contact connection of poles of the battery cell (10), an insulation layer (14) is provided on a portion of the battery casing of the battery cell (10), fragments (18) of an insulation material are adhered to an area (16) arranged between the electric contact member (12) and the insulation layer (14) of the battery casing, and this relates to a method for electrically insulating the area (16) of the battery casing. The method provides the insulation material as a wound strip (20), pulls and separates the fragments (18) from the wound strip (20), and adheres the fragments (18) to the battery casing.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a method for isolating battery cells according to the preamble of claim 1.

[0002] A battery cell of the above-mentioned type has a battery casing with at least one electrical contact element for electrical contacting of the poles of the battery cell.

[0003] In order to electrically insulate the battery casing, an insulating layer is periodically applied to a portion of the battery casing of the battery cells. This can be done over most of the surface of the battery casing, and does not pose any special technical problems. However, in practice, the battery casing has characteristics in some places that make it difficult or even impossible to apply an insulating layer.

[0004] Therefore, in the prior art, methods have been developed to provide additional insulating means to the insulating layer in order to provide sufficient electrical insulation of the battery casing.

[0005] For example, German Patent Applications DE 102011077292 and DE 102017216673 disclose methods for separately insulating the welded seams of such battery casings by covering them with strips of insulating material.

[0006] Another particularly difficult point for electrical insulation of such battery casings is the electrical insulation of the areas of the battery casing that are located between the electrical contacts of the battery casing and the insulating layer. In practice, it is often not possible, or at least not with an acceptable effort, for the insulating layer applied to a part of the battery casing of a battery cell to reach the vicinity of the electrical contacts, thereby eliminating the need to electrically insulate the areas of the battery casing that are located between the contacts and the insulating layer by means of a separate insulating means.

[0007] In practice, electrical insulation of such areas in the prior art is achieved by bonding pieces of insulating material to these areas, thereby electrically insulating them. In this case, in the prior art, the pieces are punched out and attached to a support, which is then wound and provided in a wound state. During the manufacture of the battery cell, the support material is unwound, the pieces are removed from the support material, and then bonded to the corresponding areas of the battery cell. These are often areas of the battery cell that surround electrical contact elements. To provide effective electrical insulation in these areas, the pieces often have cutouts. The pieces are then bonded in such a way that the contact elements pass through the cutouts, thereby surrounding the contact elements.

[0008] However, a disadvantage of this method is the relatively high cost of electrical insulation, since the pieces must be provided to fit the insulated area to which they are to be bonded. Accordingly, individually pre-fabricated pieces are produced on a carrier material, which leads to extremely high material costs for the pieces. Furthermore, handling pre-fabricated pieces is often difficult due to the shape of the pieces, in which the cutouts are often only at least partially surrounded by very thin strips of insulating material.

[0009] The object of the present invention is therefore to provide a method for insulating battery cells which is associated with lower material costs and which can be easily implemented.

[0010] This problem is solved by a method for isolating battery cells with the features of claim 1. The features of the dependent claims relate to advantageous embodiments.

[0011] The battery cells to be insulated have a battery casing with electrical contact elements for electrical contacting of the poles of the battery cells, in particular secondary batteries and / or accumulators, for example lithium-ion accumulators.

[0012] The battery casing of the battery cell is provided with an insulating layer, which may be provided in particular after the battery casing has been closed, and the battery casing may be made of, in particular, a metallic material.

[0013] The battery cells may be prismatic cells. Prismatic cells have a battery casing with an at least substantially rectangular parallelepiped basic shape. This basic shape defines corresponding faces of the battery casing. In this connection, the insulating layer may be applied to a part of the battery casing, in particular including four faces defined by the basic shape, which form the outer periphery of the battery casing with respect to the basic shape and which are adjacent to one another, in particular without contact elements arranged thereon.

[0014] In this case, the insulating layer can be formed, in particular, by a strip-shaped material that is applied to the battery cell. In particular, to provide the battery cell with an insulating layer, the battery cell can be wrapped with a strip-shaped material, which can in particular be a film. It has been found that battery cells insulated in this way are particularly well suited to the above-mentioned method.

[0015] Pieces of insulating material are adhered to the battery casing in areas located between the electrical contacts and the insulating layer, thereby electrically insulating these areas. These areas may surround the electrical contacts. In particular, in battery cells in which an insulating layer is applied in the manner described above, it is often necessary to electrically insulate these areas with insulating means supplementing the insulating layer, since the insulating layer often cannot be formed sufficiently close to the contacts, or at least not with acceptable effort.

[0016] This problem is solved in particular by providing the insulating material as a wound strip, unwinding and separating the pieces from the wound strip, and then gluing the pieces to the battery casing. The insulating material may in particular be polyethylene terephthalate (PET).

[0017] In connection with the present invention, it has been found that the insulation problem can also be solved by unwinding and separating pieces from a wound strip of insulating material and then gluing them to the area of ​​the battery casing to be insulated. However, wound strips of insulating material can be provided at a much lower cost than finished pre-fabricated pieces provided on a support material. This can significantly reduce the material costs involved in the method of insulating the battery casing.

[0018] The method may envisage applying a self-adhesive coating to the strip before winding, which makes the method easier to carry out with regard to the formation of adhesion of the pieces, since adhesion can be easily produced via the self-adhesive coating.

[0019] The method may envisage forming cutouts in the strip before winding it. This allows a semi-finished product to be produced that is tailored to the insulation problem to be solved, without losing the main reason for the important advantages in terms of material costs and handling, namely, providing the strip as a continuous wound strip, which still leads to a reduction in costs. The cutouts can be formed in the strip, for example, by punching pieces of the strip out of the strip. Such punching allows the cutouts to be formed inexpensively.

[0020] The strip with cutouts allows the segment to be glued to the area of ​​the battery casing so that the contact elements pass through the cutouts in the segment and the segment surrounds the contact elements. In this way, the area of ​​the battery casing that surrounds the contact elements and is located between the contact elements and the insulating layer can be electrically insulated by a single segment. In this case, the cutouts are specifically adapted to the contact elements and are distributed over the length of the strip, so that when the segments are separated from the strip, each segment has one cutout.

[0021] Alternatively and / or additionally, the method may involve gluing multiple segments to areas of the battery casing so that they overlap one another, thereby combining these segments to form a single, coherent segment unit. In this way, even complex geometric shapes of the area to be insulated by the segments can be insulated, as the segment unit mimics the shape of the combined segment unit. This "patchwork" insulation has proven to be well suited for reliably electrically insulating the corresponding areas of the battery casing of the battery cell. At the same time, the segments can be separated from the wound strip, ideally from inexpensive semi-finished products already available on the market.

[0022] The method may envisage combining a plurality of segments, whereby each segment unit has a cutout surrounded by the segment, through which the contact element passes, so that the segment unit surrounds the contact element, and in this way the segment unit may also provide insulation surrounding the contact element.

[0023] This method may involve providing multiple wound strips, each with a different width, unwinding and separating pieces from the wound strips, and assembling fragment units from the pieces of strips of different widths. Using strips of different widths in this way allows the possible geometric shapes of the fragment units to be varied more easily and diversified than if only one strip with a single width were used as the fragment source. In particular, two wound strips of different widths can be provided, and fragments can be unwound and separated from the two wound strips. In this case, fragment units may be assembled from two pieces of each of the two strips. In this case, fragment units may be assembled so that the pieces of the same strip are located on opposite sides of the contacts. Such fragment units allow particularly good insulation of the areas around the contacts of each cell, which are typically required for insulating prismatic cells. The fragment units configured in this way can be particularly well adapted to these areas in terms of their geometry.

[0024] Alternatively and / or additionally, the method may provide for bonding the fragments and / or fragment units to a plurality of regions of the battery casing that are arranged between the contact elements and the insulating layer, resulting in a plurality of mutually separate fragments and / or fragment units. Such an arrangement of fragments and / or fragment units may be particularly useful when the insulating layer is sufficiently close to the contact elements in partial sections around the contact elements, thereby making it possible to dispense with additional insulation of the battery casing between the contact elements and the insulating layer in these partial sections. In this case, it is sufficient to bond the fragments and / or fragment units between the contact elements and the insulating layer only in the regions that are located in the partial sections around the contact elements where the insulating layer does not fully reach the contact elements.

[0025] The contact members may be arranged on a plane defined by the basic shape of the battery.

[0026] The method may in particular provide that the contact elements are arranged on a surface defined by the basic shape of the battery cell. Alternatively and / or additionally, a plurality of, in particular two, contact elements may be arranged on the surface defined by the basic shape of the battery cell. It is particularly advantageous if, when the battery cell is provided with an insulating layer, an edge region of the insulating layer applied to a surface adjacent to the surface containing the one or more contact elements is applied to this surface so that it extends along the edge along the surface of the battery casing and into the surface containing the one or more contact elements. For this purpose, in particular, the film forming the insulating layer can be bent and / or folded to encompass the edge.

[0027] The pieces and / or fragment units may be glued to an edge region of the insulating layer in an overlapping manner. The edge region may be an edge extending in a plane along the surface of the battery casing, particularly along the edge, and including one or more contact elements. The overlap between the insulating layer and the pieces and / or fragment units may ensure reliable electrical insulation even in the transition region between the pieces and / or fragment units and the insulating layer. This is particularly advantageous when the edge region is an edge region.

[0028] The battery cell may have an at least substantially rectangular parallelepiped basic shape. On opposing sides of the basic shape of the battery cell, the battery cell may each have a contact element and one or more areas of the battery casing where the pieces and / or piece units are glued, the areas being arranged between the contact element and the insulating layer. The savings possible with such a battery cell are particularly high, since electrical insulation by the glued pieces is achieved on two opposing sides of the battery cell, thereby replacing two costly pieces that would have been individually supported on a carrier material in the prior art.

[0029] In the following, further practical embodiments of the invention will be described with reference to the drawings. [Brief explanation of the drawings]

[0030] [Figure 1] FIG. 1 is a schematic diagram illustrating a method according to the prior art. [Figure 2] 2 is a schematic diagram illustrating one exemplary method for isolating battery cells according to a first embodiment. FIG. [Figure 3] FIG. 10 is a schematic diagram illustrating one exemplary method for isolating battery cells according to a second embodiment. [Figure 4] FIG. 10 is a schematic diagram illustrating one exemplary method for isolating battery cells according to a third embodiment.

[0031] The figures show a plan view of the face of the battery cell 10 in an unattached state (A), a fragment to be attached to the battery cell (B), and a plan view of the face in an attached state (C).

[0032] The surfaces defined by the basic shape of the battery cell 10 shown in each figure include, in the illustrated example, a centrally located contact element 12. The battery cell 10 includes an insulating layer 14. In the illustrated example, the insulating layer 14 is applied to a portion of the battery casing, which has four surfaces (not shown) defined by the basic shape that form the outer periphery of the basic shape of the battery casing and are adjacent to each other when no contact elements are arranged thereon. If the battery cell 10 is provided with an insulating layer 14, the edge regions of the insulating layer 14 are applied to the illustrated surfaces on which the contact elements 12 are arranged. In this case, the edge regions extend along the surface of the battery casing along the edges within the illustrated surface including the contact elements 12. However, in this case, the insulating layer 14 does not reach the contact elements 12 so as to provide sufficient insulation in the area of ​​the contact elements 12. Rather, areas 16 of the battery casing located between the electrical contact elements 12 and the insulating layer 14 remain uninsulated.

[0033] A method according to the prior art is shown in Figure 1. This state of the battery cell 10 is exemplarily shown in Figure 1A.

[0034] Prior art methods contemplate providing a strip 18 of insulating material and adhering it to a region 16 of the battery casing, where the strip 18 may be adhered to the battery cell 10 so as to overlap an edge region of the insulating layer 14. The resulting battery cell 10 with the strip 18 adhered thereto is shown in FIG. 1C.

[0035] The pieces 18 used according to the prior art have cutouts 19. The contact elements 12 are guided through the cutouts 19 of the pieces 18 when the pieces 18 are bonded to the battery cells 10. Thus, in the prior art example shown in FIG. 1 , the pieces 18 surround the contact elements 12.

[0036] The above-described method for insulating a battery cell 10 assumes that, in a first embodiment shown in Figure 2, the insulating material is provided as a rolled strip 20. From the strip 20, a segment 18, illustratively shown in Figure 2B, is unwound and cut, and then the segment 18 is adhered to the battery cell 10, illustratively shown in Figure 2A, resulting in the battery cell 10 shown in Figure 2C.

[0037] 2, the segments 18 also surround the contact elements 12, which are guided through cutouts 19 in the segments 18 when the segments 18 are glued to the battery cell 10. Correspondingly, the strips 20 shown by way of example in FIG. 2D already have cutouts 19. When the segments 18 are cut off from the strip 20, the cutting points 22 can be selected in the illustrated example so that each segment 18 has only one cutout 19 for the contact element 12.

[0038] In the example shown in FIG. 3 , as can be seen from FIG. 3A , the edge regions of the insulating layer 14 are sufficiently close to the contact elements 12 in partial sections around the contact elements 12, making it possible to dispense with additional insulation of the battery casing between the contact elements 12 and the insulating layer 14 in these partial sections around the contact elements 12. As a result, the battery cell 10 exemplarily shown in FIG. 3A has, on the exemplarily shown surface, two battery casing regions 16 arranged in partial sections around the contact elements 12 where the insulating layer 14 is not sufficiently close to the contact elements 12. In this case, the method can be envisioned as bonding each of these battery casing regions 16 to a respective piece 18, exemplarily shown in FIG. 3B . Correspondingly, the pieces 18 are bonded to the battery cell 10 as exemplarily shown in FIG. 3C , resulting in two separate pieces 18. In this illustrated example, the pieces 18 adhered to the battery cell 10 may also overlap the edge regions of the insulating layer 14 .

[0039] The strip 20 shown exemplarily in FIG. 3D is also provided in rolled form and represents one very inexpensive embodiment of a pre-made product for the piece 18 .

[0040] In the example shown in Fig. 4, the configuration of the battery cell 10 as shown in Fig. 4A corresponds, by way of example, to the battery cell 10 shown in Fig. 1 and Fig. 2. To insulate the region 16 of this battery cell 10 surrounding the contact member 12, in the example shown in Fig. 4, one fragment unit is formed from four fragments 18 as shown, by way of example, in Fig. 4B. When the battery cell 10 is bonded, the fragments 18 shown in Fig. 4B combine to form the fragment unit shown in Fig. 4C.

[0041] 4D and 4E exemplarily show strips 20 made of insulating material, from which segments 18 are cut to produce the segments 18 shown in FIG. 4B. As in the illustrated example, strips 20 of different widths can be used to obtain segments 18 with different geometries, and in this case, the segments 18 can be combined to form segment units whose geometry is preferably adapted to the insulated region 16 of the battery casing.

[0042] The features of the invention disclosed in the specification, the drawings and the claims may, both individually and in any combination, be important for realizing the invention in its various embodiments. The invention may be modified within the framework of the claims and taking into account the knowledge of the person skilled in the art responsible. [Explanation of symbols]

[0043] 10 battery cells 12 Contact member 14 Insulating layer 16 areas 18 Fragments 19 Cutout 20 strips 22 Cutting point A Unbonded state B. Pieces to be attached to the battery cell C. Adhesion state D,E Insulation materials provided

Claims

1. A method for isolating a battery cell (10), comprising: The battery cell (10) has a battery casing with electrical contact members (12) for electrical contact connection of the poles of the battery cell (10), a method for electrically insulating a battery casing of a battery cell, the method comprising: providing an insulating layer on a portion of the battery casing of the battery cell; and adhering a piece of insulating material to an area of ​​the battery casing disposed between the electrical contact member and the insulating layer, thereby electrically insulating the area of ​​the battery casing; providing the insulating material as a wound strip (20), unwinding and separating the pieces (18) from the wound strip (20), and then adhering the pieces (18) to the battery casing; A plurality of the segments (18) are adhered to the area (16) of the battery casing in an overlapping manner, thereby combining the segments (18) to form a single coherent segment unit. A method characterized by:

2. 2. The method of claim 1, wherein the strip (20) is provided with a self-adhesive coating before being wound.

3. 3. The method according to claim 1, wherein cutouts (19) are formed in the strip (20) before winding the strip (20), in particular by punching pieces of the strip (20) out of the strip (20).

4. 3. The method of claim 1, further comprising adhering the piece (18) to the area of ​​the battery casing such that the contact elements (12) pass through cutouts (19) provided in the piece (18) and the piece (18) surrounds the contact elements.

5. 3. The method according to claim 1, further comprising combining the fragments (18) so that each fragment unit has a cutout (19) surrounded by each fragment (18), through which the contact element (12) passes, thereby surrounding the fragment unit with the contact element (12).

6. 3. The method according to claim 1, further comprising the steps of: providing a plurality of, in particular two, wound strips (20) each having a different width; unwinding and separating the segments (18) from the plurality of wound strips (20); and assembling the segment units from the segments (18) of the strips (20) each having a different width, in particular so that the segments (18) of the same strip (20) are arranged on opposite sides of the contact element (12).

7. 3. The method according to claim 1 or 2, wherein the pieces (18) and / or the fragment units are adhered to a plurality of regions (16) of the battery casing arranged between the contact members (12) and the insulating layer (14), thereby resulting in a plurality of mutually separate pieces (18) and / or fragment units.

8. 3. The method according to claim 1, wherein the contact member (12) is arranged on a surface defined by the basic shape of the battery cell (10), and when providing the insulating layer (14) on the battery cell (10), an edge region of the insulating layer (14) is attached to the surface, and the fragments (18) and / or fragment units are overlapped and adhered to the edge region.

9. 3. The method according to claim 1, wherein the battery cell (10) has a basic shape that is at least substantially rectangular parallelepiped and has, on opposite sides of the basic shape of the battery cell (10), one contact element (12) each and an area (16) of the casing, arranged between the contact element (12) and the insulating layer (14), where the fragments and / or fragment units are to be glued.

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