Pouch cell and stack

Abstract

A pouch cell having a positive contact lug and a negative contact lug, with which the pouch cell can be electrically contacted and charged and discharged in this way, wherein the pouch cell has a planar design and has a cell top side and a cell bottom side located opposite the cell top side, wherein the positive contact lug has a conductive coating on the cell top side and an insulating coating on the cell bottom side and the negative contact lug has an insulating coating on the cell top side and a conductive coating on the cell bottom side, or vice versa, wherein the positive contact lug has an insulating coating on the cell top side and a conductive coating on the cell bottom side and the negative contact lug has a conductive coating on the cell top side and an insulating coating on the cell bottom side.

Description

TECHNICAL FIELD

[0001] The invention relates to a pouch cell having a positive contact lug and a negative contact lug, with which the pouch cell can be electrically contacted and can be charged and discharged in this way. The pouch cell has a planar design and has a cell top side and a cell bottom side located opposite the cell top side. The invention likewise relates to a stack having at least two such pouch cells. BACKGROUND

[0002] Such a pouch cell is known, for example, from EP 3 588 614 A1. SUMMARY

[0003] It is an object of the invention to provide a pouch cell, a stack having at least two pouch cells, and a method for producing a stack having a plurality of pouch cells, which facilitates a simple and reliable contact connection.

[0004] For a pouch cell, the object is achieved in that the positive contact lug has a conductive coating on the cell top side and an insulating coating on the cell bottom side, and the negative contact lug has an insulating coating on the cell top side and a conductive coating on the cell bottom side, or vice versa, in that the positive contact lug has an insulating coating on the cell top side and a conductive coating on the cell bottom side, and the negative contact lug has a conductive coating on the cell top side and an insulating coating on the cell bottom side.

[0005] The invention comprises the finding that pouch cells are difficult to handle in mass production, since the contact lugs of the pouch cells are usually located close to one another, and if the pouch cells are not handled carefully, the pouch cells can short circuit. Furthermore, it has been found that, due to the construction of the pouch cells, the pouch cells could not previously be resistance-welded, or at least it could be comparatively difficult to achieve the purpose of electrical contacting by resistance welding. This leads to a high level of technical and financial outlay for automated facilities for making electrical contact connections of individual pouch cells in the mass production of battery packs or stacks having pouch cells.

[0006] In a particularly preferred refinement, the insulating coating consists of or comprises a ceramic. The conductive coating can consist of or comprise a tin alloy. It has been found to be advantageous if the conductive coating is applied in particular in the form of a tin-containing solder paste. The flux component of the solder paste usually evaporates when the contact lugs are welded or soldered.

[0007] It has been found to be advantageous if the positive contact lug consists of or comprises aluminum. The negative contact lug can consist of or comprise nickel. In a further preferred refinement, the electrically conductive coating consists of a material different from the material of the contact lug. It has been found to be advantageous if the insulating coating consists of a material different from the material of the contact lug.

[0008] In a further preferred refinement, the electrically conductive coating is provided on a self-adhesive carrier material, which is preferably applied to or to be applied to the contact lug. The insulating coating can be provided on a self-adhesive carrier material, wherein the self-adhesive carrier material is preferably applied to or to be applied to the contact lug.

[0009] It has been found to be advantageous if the positive contact lug and the negative contact lug are each flat and designed for contact connection by means of crimping and / or by means of soldering. In a further preferred refinement, the cell top side and / or the cell bottom side has an essentially flat design.

[0010] In a further preferred refinement, the electrically conductive coating has an electrical conductivity of at least 10E6 S / m. It has been found to be advantageous if the insulating coating has an electrical conductivity of less than 10E-8 S / m.

[0011] For the stack, the object is achieved in that the first of the two pouch cells, in particular only the first pouch cell, is formed in such a way that the positive contact lug has an electrically conductive coating on the cell top side and an insulating coating on the cell bottom side, and the negative contact lug has an insulating coating on the cell top side and an electrically conductive coating on the cell bottom side, or the positive contact lug has an insulating coating on the cell top side and an electrically conductive coating on the cell bottom side, and the negative contact lug has an electrically conductive coating on the cell top side and an insulating coating on the cell bottom side, and wherein the complementary contact lugs of the two pouch cells overlap, respectively. It has been found to be advantageous if the complementary contact lugs overlap in the stacking direction. In a particularly preferred refinement, the complementary contact lugs coincide in the stacking direction. The complementary contact lugs are intended to be understood as meaning in particular the positive contact lug of a first type of pouch cell paired with the negative contact lug of a second type of pouch cell, and / or the negative contact lug of a first type of pouch cell paired with the positive contact lug of a second type of pouch cell. In a further preferred refinement, a plurality of first pouch cells and second pouch cells are provided and stacked alternately. In the context of the present application, the first pouch cell is intended to be understood as meaning in particular a first type of pouch cell. In the context of the present application, the second pouch cell is intended to be understood as meaning in particular a second type of pouch cell. It has been found to be advantageous if the first pouch cell is formed according to the features described with reference to the pouch cell.

[0012] In a particularly preferred refinement, the pouch cells are electrically contact-connected to one another via their respective connecting elements. Adjacent pouch cells are preferably electrically connected in series with one another. Multiple stacks of pouch cells electrically interconnected in this way can be electrically connected in parallel (for example, as part of a battery pack) in order to be used to power a handheld power tool.

[0013] For the stack, the object is achieved by a method comprising the following steps:

[0014] - providing a plurality of pouch cells, wherein the pouch cells are each equipped with a positive contact lug and a negative contact lug by means of which the pouch cells can be electrically contacted and can be charged and discharged in this way, wherein the pouch cells have a planar design and have a cell top side and a cell bottom side located opposite the cell top side,

[0015] - carrying out a coating process on a subset of the pouch cells, preferably on half of the pouch cells, in such a way that the positive contact lug has a conductive coating on the cell top side and an insulating coating on the cell bottom side and the negative contact lug has an insulating coating on the cell top side and a conductive coating on the cell bottom side, or the positive contact lug has an insulating coating on the cell top side and a conductive coating on the cell bottom side and the negative contact lug has a conductive coating on the cell top side and an insulating coating on the cell bottom side, wherein the pouch cells coated in this way define a first type and the remaining pouch cells form a second type,

[0016] - assembling the stack by alternately stacking pouch cells of the first type and the second type, wherein the complementary contact lugs of the pouch cells respectively overlap.

[0017] It has been found to be advantageous to carry out the coating process before the step of assembling the stack. As an alternative, the coating process can be carried out after the step of assembling the stack. In this alternative, it has been found to be advantageous for the coating process to involve the application of a self-adhesive carrier material on which the conductive coating and / or the insulating coating is respectively provided.

[0018] In a particularly preferred refinement, the stack is electrically contact-connected by means of extrusion and / or by means of fusion.

[0019] Further advantages will become apparent from the following description of the drawings. In the drawings, a plurality of exemplary embodiments of the present application are shown. The drawings, the description, and the claims contain numerous combined features. The person skilled in the art will also expediently consider these features individually and combine them to form useful further combinations. BRIEF DESCRIPTION OF DRAWINGS

[0020] In the drawings, identical and similar components are denoted by the same reference signs. In the drawings:

[0021] Figure 1 A pouch cell of the prior art is shown;

[0022] Figure 2 A first preferred exemplary embodiment of a pouch cell according to the present application is shown;

[0023] Fig. 3 shows a first preferred exemplary embodiment of a stack according to the present application; and

[0024] Figure 4 A first preferred exemplary embodiment of a method according to the present application is shown. DETAILED DESCRIPTION

[0025] Figure 1 A pouch cell 200 of the prior art is shown in Fig. 1. The pouch cell 200 is equipped with a positive contact lug 210 and a negative contact lug 220, by which the pouch cell 200 can be electrically contacted and can be charged and discharged in this way. The pouch cell 200 has a planar design and has a cell top side 240 and a cell bottom side 260, which is located opposite the cell top side 210.

[0026] Figure 2 A preferred exemplary embodiment of a pouch cell 100 according to the present application is shown. The pouch cell 100 is equipped with a positive contact lug 110 and a negative contact lug 120, by which the pouch cell 100 can be electrically contacted and can be charged and discharged in this way. Here, for example, the positive contact lug 110 consists of aluminum. For example, the negative contact lug 120 consists of nickel. The cell top side 140 and the cell bottom side 160 of the pouch cell are essentially flat.

[0027] The cell top side 140 of the pouch cell 100 is understood to mean in particular the flat side of the pouch cell 100 that is on top in the stacking direction SR when looking at the end side of the pouch cell 100 and when the positive contact lug 110 is located to the left of the negative contact lug 120. The cell bottom side 140 of the pouch cell 100 is understood to mean in particular the flat side of the pouch cell 100 that is on the bottom in the stacking direction SR when looking at the end side of the pouch cell 100 and when the positive contact lug 110 is located to the left of the negative contact lug 120. This is the case in the following view B-B of Fig. 2, respectively. Figure 2

[0028] As can be seen from Fig. 2, the positive contact lug 110 and the negative contact lug 120 are arranged on the same side of the pouch cell 100. In other words, the positive contact lug 110 and the negative contact lug 120 are arranged on the same side of the pouch cell 100 in the stacking direction SR. In other words, the positive contact lug 110 and the negative contact lug 120 are arranged on the same side of the pouch cell 100 in the stacking direction SR. Figure 2 ​As can be gathered, the positive contact lug 110 has a conductive coating 115 on the cell top side 140, which is provided for example in the form of a tin-containing solder paste. The positive contact lug 110 has an insulating coating 117 on the cell bottom side 160, which is provided for example in the form of a ceramic. The negative contact lug 120 is equipped with an insulating coating 127 in the form of a ceramic on the cell top side 140. The negative contact lug 120 has a conductive coating 125 in the form of a tin-containing solder paste on the cell bottom side 160. The coatings 115, 117, 125, 127 substantially completely cover the respective surfaces of the contact lugs 110, 120.

[0029] The insulating coating 117 of the positive contact lug 110 and the insulating coating 127 of the negative contact lug 120 are composed for example of the same material. The conductive coating 115 of the positive contact lug 110 and the conductive coating 125 of the negative contact lug 120 are composed for example of the same material. This is not necessarily the case in both cases.

[0030] In alternative exemplary embodiments (not shown here), it is in principle possible to coat the contact lugs in such a way that the positive contact lug has an insulating coating on the cell top side and a conductive coating on the cell bottom side, and the negative contact lug has a conductive coating on the cell top side and an insulating coating on the cell bottom side. It has been found to be advantageous to retain the initially chosen coating alternative in batches (or in the case of a stack).

[0031] Figure 2 The pouch cell 100 of the type creates the basis for a simple and reliable contact connection of the stack 500, which will be explained in more detail below with reference to Fig. 3. Here, Figure 3A A stack 500 is shown in the assembled state, i.e. before the electrical contact connection. Figure 3B The stack 500 is shown with the electrical contact connection.

[0032] The stack 500 has for example six pouch cells 100, 200 stacked in the stacking direction SR. Three pouch cells 100 are of the first type, i.e. the positive contact lug 110 has a conductive coating 115 on the cell top side and an insulating coating 117 on the cell bottom side, and the negative contact lug 120 has an insulating coating 127 on the cell top side and a conductive coating 125 on the cell bottom side. The three pouch cells 100 of the first type correspond to the exemplary embodiment of the type. Figure 2 The stack 500 has for example six pouch cells 100, 200 stacked in the stacking direction SR. Three pouch cells 100 are of the first type, i.e. the positive contact lug 110 has a conductive coating 115 on the cell top side and an insulating coating 117 on the cell bottom side, and the negative contact lug 120 has an insulating coating 127 on the cell top side and a conductive coating 125 on the cell bottom side. The three pouch cells 100 of the first type correspond to the exemplary embodiment of the type. Figure 1 The three pouch cells 200 of the second type are shown in Fig. 2, i.e. they correspond to the prior art pouch cell. In other words, here for example half of the total of six pouch cells are of the first type and the other half are of the second type. According to the exemplary embodiment of the type, Figure 2 Only pouch cells 100 of the first type are revealed in the exemplary embodiment of the type.

[0033] The first type of pouch cell 100 and the second type of pouch cell 200 are alternately stacked, respectively, as observed in the exemplary embodiment shown in the stacking direction SR (i.e. from bottom to top): first type of pouch cell 100, second type of pouch cell 200, first type of pouch cell 100, etc. Here, the second type of pouch cell 200 is rotated by 180 degrees with respect to the stacking direction SR, such that the positive contact lug 110 of the first type of pouch cell 100 overlaps, in particular coincides, in the stacking direction with the negative contact lug 220 of the second type of pouch cell 200. The negative contact lug 120 of the first type of pouch cell 100 overlaps in the stacking direction with the positive contact lug 210 of the second type of pouch cell 200. In the exemplary embodiment of Fig. 3, the negative contact lug 120 of the first type of pouch cell 100 coincides with the positive contact lug 210 of the second type of pouch cell 200.

[0034] Figure 3B The stack 500 with the electrical contact connections is shown in Fig. 3. The electrical contact connections can be performed, for example, by means of extrusion in the stacking direction SR and / or by means of soldering. For reasons of example, the stack 500 is shown without the soft pouch cells. Figure 3B The outline of the soft pouch cells is not shown in Fig. 3. It should also be pointed out that the layer thickness of the electrically conductive coating 115 is typically reduced in the soldering process, if the electrically conductive coating is provided, for example, in the form of a solder paste. Due to the alternately stacking of the first type of pouch cell and the second type of pouch cell, wherein the second type of pouch cell is rotated by 180 degrees with respect to the stacking direction SR, a series connection of the electrical connections is created in the stack 500. The final flow of the electrical current I (physical current direction) is indicated by the directional arrows. Here, the horizontally directed arrows indicate the electrical current within the respective soft pouch cell, and the vertically directed arrows indicate the electrical current between the contact lugs of the respective adjacent pouch cells.

[0035] Finally, a first preferred exemplary embodiment of a method for producing a stack with a plurality of soft pouch cells according to the present application is shown in Fig. 4. For example, the stack 500 shown in Fig. 3 can be obtained by means of this method. Figure 4 The stack 500 shown in Fig. 3. Figure 3B In a first step S1, a plurality of soft pouch cells is provided, wherein the soft pouch cells are each equipped with a positive contact lug and a negative contact lug by means of which the soft pouch cells can be electrically contacted and can be charged and discharged in this way. The soft pouch cells have a planar design and have a cell top side and a cell bottom side which is located opposite the cell top side.

[0036] In a first step S1, a plurality of soft pouch cells is provided, wherein the soft pouch cells are each equipped with a positive contact lug and a negative contact lug by means of which the soft pouch cells can be electrically contacted and can be charged and discharged in this way. The soft pouch cells have a planar design and have a cell top side and a cell bottom side which is located opposite the cell top side.

[0037] In a subsequent step S2, half of the pouch cells are subjected to a coating process in such a way that the positive contact lug has a conductive coating on the cell top side and an insulating coating on the cell bottom side and the negative contact lug has an insulating coating on the cell top side and a conductive coating on the cell bottom side. The pouch cells obtained in this way define a first type (see Figure 2 ). The remaining pouch cells (the respective contact lug is not additionally coated) define a second type (see Figure 1 ).

[0038] In a subsequent step S3, the stack is assembled by alternately stacking the first and second type pouch cells, wherein the complementary contact lugs of the pouch cells are in each stacking direction self-coincident (see Figure 3A ).

[0039] In a subsequent step S4, the stack is electrically contact-connected by pressing (exerting pressure in the stacking direction) and welding (heat induction). For example, at the end of step 4, there is Figure 3B the stack shown.

[0040] List of reference signs

[0041] 100 pouch cell

[0042] 110 positive contact lug

[0043] 115 conductive coating

[0044] 117 insulating coating

[0045] 120 negative contact lug

[0046] 125 conductive coating

[0047] 127 insulating coating

[0048] 140 cell top side

[0049] 160 cell bottom side

[0050] 200 prior art pouch cell

[0051] 210 positive contact lug

[0052] 220 negative contact lug

[0053] 240 cell top side

[0054] 260 cell bottom side

[0055] I current

[0056] SR stacking direction

[0057] S1. S4 method steps

Claims

1. A pouch cell (100) having a positive contact tab (110) and a negative contact tab (120) by which the pouch cell (100) can be electrically contacted and in this way charged and discharged, wherein, The pouch cell (100) has a planar design and has a cell top side (140) and a cell bottom side (160) located opposite the cell top side (140), characterized in that the positive contact lug (110) has a conductive coating (115) on the cell top side and an insulating coating (117) on the cell bottom side, and the negative contact lug (120) has an insulating coating (127) on the cell top side and a conductive coating (125) on the cell bottom side, or the positive contact lug has an insulating coating on the cell top side and a conductive coating on the cell bottom side, and the negative contact lug has a conductive coating on the cell top side and an insulating coating on the cell bottom side.

2. The pouch cell (100) as claimed in claim 1, characterized in that The insulating coating (117, 127) consists of or comprises a ceramic, and / or the conductive coating (115, 125) consists of or comprises a tin alloy.

3. The pouch cell (100) as claimed in claim 1 or 2, characterized in that The positive contact lug (110) consists of or comprises aluminum, and / or the negative contact lug (120) consists of or comprises nickel.

4. The pouch cell (100) as claimed in claim 1 or 2, characterized in that The conductive coating (115, 125) and / or the insulating coating (117, 127) consists of a material different from the material of the contact lug.

5. The pouch cell (100) as claimed in claim 1 or 2, characterized in that The conductive coating (115, 125) and / or the insulating coating (117, 127) is provided on a self-adhesive carrier material.

6. The pouch cell (100) as claimed in claim 1 or 2, characterized in that The positive contact lug (110) and the negative contact lug (120) are each flat and designed for contact connection by means of pressing and / or by means of soldering.

7. The pouch cell (100) as claimed in claim 1 or 2, characterized in that The cell top side (140) and the cell bottom side (160) are substantially flat.

8. A stack (500) of at least two pouch cells (100, 200), wherein The pouch cells (100, 200) are each equipped with a positive contact lug (110, 210) and a negative contact lug (120, 220) by means of which electrical contact can be made to the pouch cells (100, 200) and in which manner the pouch cells can be charged and discharged, wherein the pouch cells (100, 200) have a planar design and have a cell top side (110, 210) and a cell bottom side (120, 200) located opposite the cell top side (110, 210), characterized in that the first pouch cell (100) of the two pouch cells (100, 200) is formed in such a way that the positive contact lug (110) has a conductive coating (115) on the cell top side and an insulating coating (117) on the cell bottom side, and the negative contact lug (120) has an insulating coating (127) on the cell top side and a conductive coating (125) on the cell bottom side, or the positive contact lug has an insulating coating on the cell top side and a conductive coating on the cell bottom side, and the negative contact lug (120) has a conductive coating on the cell top side and an insulating coating on the cell bottom side, and wherein the complementary contact lugs (110, 220; 120, 210) of the two pouch cells (100, 200) overlap, respectively.

9. The stack (500) of claim 8, characterized in that only the first pouch cell (100) is formed in such a way that the positive contact lug (110) has a conductive coating (115) on the cell top side and an insulating coating (117) on the cell bottom side, and the negative contact lug (120) has an insulating coating (127) on the cell top side and a conductive coating (125) on the cell bottom side, or the positive contact lug has an insulating coating on the cell top side and a conductive coating on the cell bottom side, and the negative contact lug (120) has a conductive coating on the cell top side and an insulating coating on the cell bottom side.

10. The stack (500) of claim 8 or 9, characterized in that a plurality of first pouch cells (100) and second pouch cells (200) are provided and stacked alternately.

11. The stack (500) of claim 8 or 9, characterized in that the first pouch cell (100) is configured as the pouch cell (100) of any one of claims 2 to 7.

12. The stack (500) of claim 8 or 9, wherein, The pouch cells (100) are electrically contact-connected to each other by their respective contact lugs (110, 210; 210, 220).

13. A method for producing a stack having a plurality of pouch cells, characterized in that The method comprises the following steps: - (S1) providing a plurality of pouch cells, wherein the pouch cells are each equipped with a positive contact lug and a negative contact lug by means of which the pouch cells can be electrically contacted and can be charged and discharged in this way, wherein the pouch cells have a planar design and have a cell top side and a cell bottom side located opposite the cell top side, - (S2) forming the first pouch cell (100) of the two pouch cells (100, 200) in such a way that the positive contact lug (110) has a conductive coating (115) on the cell top side and an insulating coating (117) on the cell bottom side, and the negative contact lug (120) has an insulating coating (127) on the cell top side and a conductive coating (125) on the cell bottom side, or the positive contact lug has an insulating coating on the cell top side and a conductive coating on the cell bottom side, and the negative contact lug (120) has a conductive coating on the cell top side and an insulating coating on the cell bottom side, and wherein the complementary contact lugs (110, 220; 120, 210) of the two pouch cells (100, 200) overlap, respectively. - (S2) applying a coating process to a subset of the pouch cells in such a way that the positive contact tab has a conductive coating on the cell top side and an insulating coating on the cell bottom side and the negative contact tab has an insulating coating on the cell top side and a conductive coating on the cell bottom side, or the positive contact tab has an insulating coating on the cell top side and a conductive coating on the cell bottom side and the negative contact tab has a conductive coating on the cell top side and an insulating coating on the cell bottom side, wherein the pouch cells coated in this way define a first type and the remaining pouch cells form a second type, - (S3) assembling the stack by alternately stacking pouch cells of the first type and of the second type, wherein the complementary contact tabs of the pouch cells respectively overlap.

14. The method of claim 13, characterized in that (S2) applying a coating process to half of the pouch cells.

15. The method of claim 13 or 14, characterized in that The stack is electrically contact-connected by pressing and / or by welding (S4).

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