WO2019201690A1

WO2019201690A1 - Method for wrapping an electrode composite with an insulating foil, and battery cell

Info

Publication number: WO2019201690A1
Application number: PCT/EP2019/059018
Authority: WO
Inventors: Chen Liu; Michael BUTZIN; Benedikt RODE
Original assignee: Robert Bosch Gmbh
Priority date: 2018-04-20
Filing date: 2019-04-10
Publication date: 2019-10-24
Also published as: DE102018206033A1

Abstract

The invention relates to a method for wrapping an electrode composite with an insulating foil (60), comprising the following steps: providing a blank (50) of the insulating foil (60) which corresponds approximately to a surface development of a cuboid and comprises at least a lower front face (33), an upper front face (34), a base face (32), a first end face (35) and a second end face (36); folding the blank (50) such that the end faces (35, 36) are disposed parallel to each other and at right angles to the lower front face (33) and at right angles to the base face (32) and that the lower front face (33) is disposed at right angles to the base face (32); applying the electrode composite to the lower front face (33); folding the blank (50) such that the upper front face (34) is disposed parallel to the lower front face (33). The invention also relates to a battery cell which comprises an electrode composite which is wrapped with an insulating foil (60) by means of the method according to the invention.

Description

description

Process for wrapping an electrode composite with an insulating film and

battery cell

The invention relates to methods for wrapping an electrode assembly for a battery cell with an insulating film. The invention also relates to a

Battery cell, which comprises an electrode assembly, which is covered with an insulating film by means of the method according to the invention. The

In particular, insulation foil prevents an electrical short circuit between the electrode composite and an electrically conductive cell housing of the battery cell.

State of the art

Battery cells, in particular lithium-ion cells and post-lithium-ion cells, have an electrode composite, which is designed, for example, in the form of an electrode coil or in the form of an electrode stack. A battery cell also has a generally prismatic or cuboid cell housing, in which the electrode assembly is arranged. The cell housing is metallic, for example, and thus electrically conductive. To avoid internal short circuits between the

Electrode composite and the cell housing, it is known the

To encase electrode composite with an insulating film.

The document DE 10 2015 108 288 A1 discloses a battery cell with an envelope made of a shrink film. To cover the battery cell, a flat shrink film material is first applied to three sides of the cuboid battery cell. The shrink film material is slightly wider than the battery cell. Subsequently, the Shrinking foil material cut, and the laterally projecting portions are placed by folding on the battery cell.

The document DE 10 2014 117 866 A1 discloses a battery cell with an insulating package. The said packaging is applied externally to the housing of the battery cell. The insulating material for the production of the packaging is provided in the form of a blank. The said blank corresponds approximately to a development of the battery cell.

Document DE 10 2008 063 120 A1 discloses a film which is produced from a copolymer, in particular polypropylene. The foil serves

in particular for packaging objects, for example

Food.

The document DE 10 2014 214 337 A1 discloses a battery cell which has inter alia an insulation element. The insulating element is formed, for example, from EPDM. The isolation element is, inter alia, on one

Housing bottom of the cell housing of the battery cell arranged.

From the document US 6,004,692 A a battery cell is known, which has an electrode assembly and an electrically conductive cell housing, in which the electrode assembly is arranged. The electrode composite is surrounded by a bag of electrically insulating material.

From document US 2014/0023906 Al a battery stack with a

Plurality of battery cells known. The battery cells each have a cuboid cell housing. Between every two adjacent ones

Battery cells each have a flat insulating film is arranged. The battery stack is inserted in an electrically insulating bag.

Disclosure of the invention

It is proposed a method for wrapping an electrode assembly, in particular for a battery cell, with an insulating film. The The inventive method comprises at least the steps mentioned below.

First of all, provision is made of a blank of the insulating film. The blank corresponds at least approximately to a development of a cuboid with a recess on one of the small end faces. The said blank comprises at least a lower front surface, an upper front surface, a

Bottom surface, a first end face and a second end face. The blank of the insulating film preferably comprises additional tabs, which serve in a later step to connect said surfaces together.

As a material for the insulating film are electrically insulating materials, such as polyethylene (PE), polypropylene (PP) or polyethylene terephthalate (PET) in question. The insulating film has, for example, a thickness in the range between 30 pm and 100 pm in order to ensure a technical implementation of the design. From the perspective of electrical insulation is the

Minimum thickness of the film 5 pm. The maximum thickness of the film is limited by the heat transfer to a maximum of 500 pm from a functional point of view.

The blank of the insulating film is formed, for example, such that the lower front surface and the upper front surface protrude away from the bottom surface at opposite folded edges. The first end face and the second end face protrude away from the lower front face, for example, at opposite fold edges.

This is followed by folding the blank of the insulation film. The blank is folded so that the two end faces are arranged parallel to each other, and that the end faces perpendicular to the lower

Front surface and are arranged at right angles to the bottom surface, and that the lower front surface is arranged at right angles to the bottom surface. The result is a partial body, which is closed on four sides, and which is open on two sides.

Subsequently, the electrode composite is applied to the lower front surface. Preferably, the resulting partial body is previously such arranged so that the lower front surface is oriented approximately parallel to the ground. The electrode composite is thus surrounded on four sides by said part body.

The electrode composite is designed in particular in the form of an electrode stack. The electrode assembly comprises a plurality of anode segments, a plurality of cathode segments and a plurality of separator segments. The

Anode segments together form an anode, the cathode segments together form a cathode, and the separator segments together form a separator which separates the anode from the cathode.

Subsequently, a folding of the blank takes place such that the upper front surface is arranged parallel to the lower front surface. The upper front surface is thus also arranged at right angles to the bottom surface and at right angles to the end surfaces. The result is a cuboid body, which is closed on five sides, and which is open on one side. The open side lies opposite the bottom surface.

The electrode composite is thus surrounded on five sides by said cuboid body. Due to the open side, which is opposite the bottom surface, for example, arrester tabs of the anode and the cathode protrude out of the cuboid body for electrical contacting of the electrode assembly.

According to an advantageous embodiment of the invention is the

Electrode assembly produced in the form of an electrode stack on the previously formed part body. These are the anode segments, the

Cathode segments and the Separatorsegmente stacked on the lower front surface of the body part to the electrode assembly.

According to another advantageous embodiment of the invention, the electrode composite is prefabricated in the form of an electrode stack. For this purpose, the anode segments, the cathode segments and the Separatorsegmente first stacked to the electrode assembly, and then the prefabricated electrode composite applied to the lower front surface of the body part.

According to a preferred embodiment of the invention are before

Applying the electrode composite on the lower front surface of the body part, the lower front surface, the bottom surface and the two end faces connected to each other. The partial body thereby has increased stability during the application of the electrode composite.

The connection of said surfaces to the partial body can be effected for example by welding, in particular ultrasonic welding or laser welding. Other joining techniques are conceivable, for example hot stamping or gluing. In this case, an adhesive coating can be applied to individual surfaces. The use of adhesive tapes is conceivable.

According to an advantageous development of the invention, the blank has a first bottom flap, which is connected to the first end face. Also, the blank has a second bottom flap, which is connected to the second end face. For example, the bottom flaps protrude away from the bottom surface at opposite fold edges. Thus, the two end faces are indirectly connected via the two bottom flaps with the bottom surface.

According to an advantageous embodiment of the invention, a support plate is applied to the lower front surface before applying the electrode composite. The electrode composite is then applied directly to the support plate and indirectly to the lower front surface. The support plate has approximately the same dimensions as the lower front surface. The support plate additionally increases the stability of the part body.

As the material for the support plate come electrically insulating materials, such as polyethylene (PE) or polypropylene (PP), in particular

Polyethylene terephthalate (PET) in question. The reinforcing element has, for example, a minimum thickness of lOOpm. A sensible upper limit for the Thickness is 500 mhh, otherwise the volumetric energy density of the cell is reduced too much. The support plate is preferably with the lower

Front surface connected, in particular by welding, for example

Ultrasonic welding or laser welding.

According to an advantageous embodiment of the invention, a reinforcing element is applied to the bottom surface before applying the electrode composite. The material used for the reinforcing element is electrically insulating materials, for example polyethylene (PE), polypropylene (PP) or polyethylene terephthalate (PET). The reinforcing element has, for example, a minimum thickness of lOOpm. A reasonable upper limit for the thickness is 500 pm, since otherwise the volumetric energy density of the cell is reduced too much.

According to a further advantageous embodiment of the invention, a reinforcing element is applied to the first end face and / or on the second end face before applying the electrode composite. The material used for the reinforcing element is electrically insulating materials, for example polyethylene (PE), polypropylene (PP) or polyethylene terephthalate (PET). The reinforcing element has, for example, a minimum thickness of lOOpm. A reasonable upper limit for the thickness is 500 pm, since otherwise the volumetric energy density of the cell is reduced too much.

After the application of the electrode composite, the upper front surface and the end surfaces are advantageously connected to one another. The cuboid body thus has an increased stability. The connection of said surfaces to the cuboid body can be achieved, for example, by welding,

in particular ultrasonic welding or laser welding. Other joining techniques are conceivable, for example gluing. In this case, an adhesive coating can be applied to individual surfaces. The use of adhesive tapes is conceivable.

According to an advantageous development of the invention, the blank has a first side flap, which is connected to the first end face. Also, the blank on a second side flap, which with the second End face is connected. The side flaps protrude, for example, at opposite fold edges of the upper front surface. Thus, the end faces are indirectly connected via the side flaps with the upper front surface.

It is proposed a further method for wrapping an electrode assembly, in particular for a battery cell, with an insulating film. The further method according to the invention comprises at least the steps mentioned below.

Thereafter, the electrode composite is applied to the lower one

Front surface. The electrode composite is in particular in the form of a

Electrode stack designed. The electrode composite comprises several Anode segments, multiple cathode segments, and multiple

Separatorsegmente. The anode segments together form an anode, the cathode segments together form a cathode, and the

Separator segments together form a separator which separates the anode from the cathode.

Subsequently, a folding of the blank of the insulation film. The blank is folded so that the two end faces are arranged parallel to each other, and that the end faces perpendicular to the lower

Front surface and are arranged at right angles to the bottom surface, and that the lower front surface is arranged at right angles to the bottom surface. Subsequently, a folding of the blank takes place such that the upper front surface is arranged parallel to the lower front surface.

The result is a cuboid body, which is closed on five sides, and which is open on one side. The open side lies opposite the bottom surface. The electrode composite is thus surrounded on five sides by said cuboid body. Due to the open side, which is opposite the bottom surface, for example, arrester tabs of the anode and the cathode protrude out of the cuboid body for electrical contacting of the electrode assembly.

According to an advantageous embodiment of the invention is the

According to another advantageous embodiment of the invention, the electrode composite is prefabricated in the form of an electrode stack. For this purpose, the anode segments, the cathode segments and the Separatorsegmente first stacked to the electrode assembly, and then the prefabricated electrode composite is applied to the lower front surface of the body part. According to a preferred embodiment of the invention, the lower front surface, the bottom surface and the two end surfaces are connected to each other after applying the electrode composite on the lower front surface of the body part.

A battery cell is also proposed which comprises an electrode composite which is enveloped by an insulating film by means of the method according to the invention. The battery cell further comprises a particular cuboid-shaped cell housing, in which the electrode assembly is arranged.

Advantages of the invention

By means of the method according to the invention, the production of a coated electrode composite is advantageously simplified and accelerated. In particular, when the electrode assembly is produced in the form of an electrode stack on the previously formed part body, the part body during the stacking of the anode segments, the cathode segments and the

Separator segments as workpiece carriers for the electrode assembly. Separate workpiece carriers are therefore not required. Also, an adhesive bond between the electrode assembly and the insulating film, especially on the front surfaces, not required. This results in a homogeneous

Pressure distribution on the electrode assembly and thus deposits of lithium are prevented and thus the life of the battery cell is increased. The fact that the sides of the electrode assembly are surrounded during the stacking of the end faces of the body part, the risk of

Impurities due to penetration of foreign bodies into the electrode assembly diminished during stacking. Reinforcement elements on surfaces of the blank additionally serve to protect the electrode assembly against mechanical influences such as impacts.

Brief description of the drawings

Embodiments of the invention will be explained in more detail with reference to the drawings and the description below.

Show it:

Figure 1 is a plan view of a blank of an insulating film for

Enclosing an electrode composite,

Figure 2 is a side view of a part body, which by folding the

Blank has emerged from FIG. 1,

Figure 3 is a side view of a cuboid body, which by

further folding of the blank has resulted from Figure 1, and

Figure 4 is a plan view of a blank of an insulating film for

Enclosing an electrode assembly according to an alternative embodiment.

Embodiments of the invention

In the following description of the embodiments of the invention, the same or similar elements are denoted by the same reference numerals, wherein a repeated description of these elements is dispensed with in individual cases. The figures illustrate the subject matter of the invention only schematically.

FIG. 1 shows a plan view of a blank 50 of an insulating film 60 for covering an electrode composite. The blank 50 corresponds approximately to a development of a cuboid. The blank 50 includes a bottom surface 32, a lower front surface 33, an upper front surface 34, a first end surface 35, a second end surface 36, a first bottom flap 37, a second bottom flap 38, a first side flap 39, and a second side flap 40.

A first fold edge 71 is located between the bottom face 32 and the bottom face 33. A second fold edge 72 is located between the bottom face 33 and the first face 35. A third fold edge 73 is located between the bottom face 32 and the first bottom tab 37 The fourth fold edge 74 is located between the lower front surface 33 and the second end surface 36. A fifth fold edge 75 is located between the bottom surface 32 and the second bottom flap 38. A sixth fold edge 76 is located between the bottom surface 32 and the upper front surface 34. A seventh Faltkante 77 is located between the upper front surface 34 and the first side flap 39. An eighth folding edge 78 is located between the upper front surface 34 and the second side flap 40th

The blank 50 has a plurality of cutting lines 65, on which the blank 50 is cut. The cut lines 65 are located between the first

End face 35 and the first bottom flap 37, between the first side flap 39 and the first bottom flap 37, between the second end face 36 and the second bottom flap 38 and between the second side flap 40 and the second bottom flap 38. The cutting lines 65 form extensions of the first folding edge 71 and the sixth folding edge 76th

FIG. 2 shows a side view of a partial body 51 which has been produced by folding the blank 50 from FIG.

First, the lower front surface 33 is folded about the first folded edge 71 relative to the bottom surface 32 by about 90 °. Subsequently, the first end face 35 is folded about the second folded edge 72 relative to the lower front face 33 by approximately 90 °. Then, the first bottom flap 37 is folded about the third folding edge 73 relative to the bottom surface 32 by about 90 °. Also, the second end face 36 is folded about the fourth folding edge 74 relative to the lower front face 33 by about 90 °. Also, the second bottom flap 38 is folded about the fifth fold edge 75 relative to the bottom surface 32 by about 90 °. After these steps of folding, the end faces 35, 36 are parallel to each other and perpendicular to the lower front surface 33. Likewise, the end faces 35, 36 are perpendicular to the bottom surface 32. Also, the

Bottom surface 32 at right angles to the end faces 35, 36. The resulting partial body 51 is on one side, which the lower front surface 33rd

opposite, open. Likewise, the partial body 51 is open on one side, which faces the bottom surface 32.

The first bottom flap 37 is connected to the first end face 35 by welding, in particular ultrasonic welding. Likewise, the second bottom flap 38 is connected to the second end face 36 by welding, in particular ultrasonic welding. Other types for connecting the bottom flaps 37, 38 with the end faces 35, 36 are conceivable, for example gluing.

Subsequently, an electrode assembly, not shown here, is applied to the lower front surface 33. Preferably, anode segments, cathode segments and separator segments are stacked on the lower front surface 33 to form the electrode composite.

FIG. 3 shows a side view of a cuboid-like body 52, which has been produced by further folding of the blank 50 from FIG.

Going out from the part body 51 shown in Figure 2, the upper

Front surface 34 folded about the sixth fold edge 76 relative to the bottom surface 32 by about 90 °. Likewise, the first side flap 39 is folded about the seventh folding edge 77 relative to the upper front surface 34 by about 90 °. Also, the second side flap 40 becomes about the eighth fold edge 78 relative to the upper one

Front surface 34 folded by about 90 °.

Now, the upper front surface 34 is arranged parallel to the lower front surface 33 and at right angles to the bottom surface 32. The side flaps 39, 40 are parallel to the end faces 35, 36 and parallel to the bottom flaps 37, 38th arranged. The side flaps 39, 40 are also arranged at right angles to the front surfaces 33, 34.

The first side flap 39 is welded, in particular

Ultrasonic welding, with the first end face 35 and with the first

Bottom flap 37 connected. Likewise, the second side flap 40 is connected to the second end face 36 and to the second bottom flap 38 by means of welding, in particular ultrasonic welding. Also other types to

Connecting the side flaps 39, 40 with the bottom flaps 37, 38 and the end faces 35, 36 are conceivable, for example gluing.

The cuboid body 52 is now closed on five sides, wherein the electrode assembly is disposed within the cuboid body 52. On a side opposite the bottom surface 32, the cuboid body 52 is open. Not shown here Ableiterfahnen the electrode assembly protrude at the open side of the cuboid body 52 out.

FIG. 4 shows a plan view of a blank 50 of an insulating film 60 for enclosing an electrode composite according to an alternative embodiment

Embodiment.

Notwithstanding the exemplary embodiment shown in FIG. 1, a reinforcement element 55 is applied to the blank 50 according to the alternative embodiment on the first end face 35. Likewise, a reinforcing element 55 is applied to the second end face 36.

After folding the blank 50 to the partial body 51 thus the reinforcing elements 55 are parallel to each other. The electrode composite is then applied between the reinforcing elements on the lower front surface 33, preferably stacked.

Alternatively or additionally, a further reinforcing element 55 may be applied to the bottom surface 32 of the blank 50. The invention is not limited to the embodiments described herein and the aspects highlighted therein. Rather, within the scope given by the claims a variety of modifications are possible, which are within the scope of expert action.

Claims

claims

1. A method for wrapping an electrode composite with a

Insulation film (60), comprising the following steps:

Providing a blank (50) of the insulating film (60) which approximately corresponds to a development of a cuboid and which has at least one lower front surface (33), an upper front surface (34), a bottom surface (32), a first end surface (35) and a second end face (36);

Folding the blank (50) such that the end faces (35, 36) are parallel to each other and perpendicular to the lower front face (33) and perpendicular to the bottom face (32), and the lower front face (33) is perpendicular to the bottom face (32) is arranged;

Applying the electrode composite to the lower front surface (33); Folding the blank (50) such that the upper front surface (34) is parallel to the lower front surface (33).

2. The method of claim 1, wherein

Anode segments, cathode segments and Separatorsegmente on the lower front surface (33) are stacked to the electrode assembly.

3. The method of claim 1, wherein

Anode segments, cathode segments and Separatorsegmente are first stacked to the electrode assembly, and

then the electrode composite is applied to the lower front surface (33).

4. The method according to any one of the preceding claims, wherein

before applying the electrode assembly, the lower front surface (33), the bottom surface (32) and the end surfaces (35, 36) are interconnected.

5. The method of claim 4, wherein

the blank (50) has a first bottom flap (37) connected to the first end face (35) and a second bottom flap (38) joined to the second end face (36).

6. The method according to any one of the preceding claims, wherein

Before applying the electrode composite, a support plate is applied to the lower front surface (33).

7. The method according to any one of the preceding claims, wherein

before applying the electrode composite, a reinforcing element (55) is applied to the bottom surface (32).

8. The method according to any one of the preceding claims, wherein

Before the application of the electrode composite, a reinforcing element (55) is applied to the first end face (35) and / or to the second end face (36).

9. The method according to any one of the preceding claims, wherein

after application of the electrode assembly, the upper front surface (34) and the end faces (35, 36) are interconnected.

10. The method of claim 9, wherein

the blank (50) has a first side flap (39) joined to the first end face (35) and a second side flap (40) joined to the second end face (36).

11. Battery cell, comprising an electrode composite,

which is coated with an insulating film (60) by the method according to any one of the preceding claims.

12. A method for wrapping an electrode composite with a

Insulation film (60), comprising the following steps:

Applying the electrode composite to the lower front surface (33); Folding the blank (50) such that the end faces (35, 36) are parallel to each other and perpendicular to the lower front face (33) and perpendicular to the bottom face (32), and the lower front face (33) is perpendicular to the bottom face (32) is arranged;

Folding the blank (50) such that the upper front surface (34) is parallel to the lower front surface (33).