Electric battery cell and its manufacturing process

Abstract

Electric battery cell (1) for an electric propulsion vehicle, said cell (1) comprising a stack of electrodes separated from each other by a porous separator film, cell 1 comprising: - an outer casing (2) defining an internal cavity in which the stack is arranged, - an electrolyte arranged in the internal cavity, - a cover (4), attached and arranged to close the internal cavity, said cell (1) comprising a junction (5) between the cover (4) and the outer casing (2), said cell (1) comprising a hydrophobic zone (6), said hydrophobic zone (6) covering the junction (5) and extending on either side of the junction (5). Figure for the abbreviation: Figure 1

Description

Title of the invention: Cell for electric battery and its manufacturing process Technical field of the invention

[0001] The invention relates to the field of electric batteries for electric motor vehicles. In particular, the invention relates to electric battery cells. More precisely, the invention relates to cylindrical type cells. Technical background

[0002] Cylindrical or prismatic type electric battery cells are widely used in the automotive industry.

[0003] These cells comprise a rigid outer casing defining an internal cavity. An array of electrodes separated from each other by a porous separator film is arranged within the internal cavity. A cover attached to the outer casing seals the internal cavity.

[0004] The cover is attached to the outer casing. This attachment of the cover to the outer casing can be done in various ways.

[0005] One of them consists of welding the cover onto the outer casing.

[0006] The weld is applied to a junction between the cover and the outer casing.

[0007] The lid and outer casing have a layer of nickel. This nickel layer has anti-corrosive properties.

[0008] The welding operation locally destroys the nickel layer. The weld and the area adjacent to it are then no longer protected against corrosion.

[0009] The invention aims to solve this problem. Summary of the invention

[0010] To this end, an electric battery cell for an electric propulsion vehicle is proposed firstly, said cell comprising a stack of electrodes separated from each other by a porous separator film, the cell comprising: - an outer casing defining an internal cavity in which the stack is arranged, - an electrolyte arranged in the internal cavity, - a lid, attached and arranged so as to close the internal cavity, said cell comprising a junction between the lid and the outer envelope, said cell comprising a hydrophobic zone, said hydrophobic zone covering the junction and extending on either side of the junction.

[0011] Thus, the hydrophobic zone is protected from corrosion. In the absence of such a hydrophobic zone, the junction and the surrounding area are susceptible to corrosion, thereby weakening the structure of the outer casing. Electrolyte leakage may occur.

[0012] Various additional features may be provided alone or in combination: - the cell includes a fixing weld on the joint, said fixing weld being intended to secure the cover to the outer casing, cell in which the hydrophobic zone completely covers the weld and extends beyond the weld; - cell in which: - the weld comprises a proximal edge located on one side of the junction and a distal edge opposite the proximal edge and located on the other side of the junction, - The hydrophobic zone has a superior border located on the side of the junction where the proximal border is situated and a inferior border opposite the superior border and located on the side of the junction where the distal border is situated, cell in which: - the upper edge is located at a first predetermined distance from the proximal edge, - the lower edge is located at a second predetermined distance from the distal edge; - the first distance is at least equal to 1 millimeter; - the second distance is at least equal to 1 millimeter; - the first distance and the second distance are approximately equal; - the outer casing includes an outer face having a coating containing Nickel; - the lid includes an outer face having a coating containing Nickel; - the hydrophobic zone has an outer surface with a microstructure allowing contact with an external liquid at an angle greater than or equal to 150°.

[0013] Secondly, a method for manufacturing a cell as previously described is proposed, the cell comprising: - an operation of supplying a sheet of a first electrode, - an operation of supplying a sheet of a first insulating separator, - an operation of supplying a sheet of a second electrode, - an operation of supplying a sheet of a second insulating separator, - an operation of successively stacking the first electrode, the first insulating separator, the second electrode, the second insulating separator so as to form a stack, - an operation of winding the stack onto itself, - an operation to supply an outer casing comprising an internal cavity, - an operation of inserting the winding into the internal cavity of the outer casing, - an operation of supplying a lid so as to close the internal cavity, the cell comprising a junction between the lid and the outer envelope, the process comprising a structuring operation so as to form a hydrophobic zone which extends on either side of the junction.

[0014] Various additional features may be provided alone or in combination: - the process includes a welding operation to create a fixing weld on the joint to secure the cover to the outer casing, said welding operation being prior to the structuring operation and said structuring operation being carried out so that the hydrophone zone fully covers the weld and extends beyond said weld; - the structuring operation is carried out in such a way as to create a hydrophobic zone in which the outer surface has a microstructure allowing contact with an external liquid at an angle greater than or equal to 150°; - the structuring operation is carried out in such a way as to remove material. Brief description of the figures

[0015] Other features and advantages of the invention will become apparent upon reading the detailed description that follows, for an understanding of which reference should be made to the accompanying drawings in which:

[0016] [Fig-1] [Fig.1] is a schematic representation of a cell according to the invention;

[0017] [Fig.2] [Fig.2] is a schematic representation of a method according to the invention. Detailed description of the invention

[0018] Figure 1 shows an electric battery cell 1. Cell 1 comprises a stack of electrodes separated by a porous separator film, not shown in the drawings.

[0019] Cell 1 comprises an outer envelope 2. The outer envelope 2 is rigid.

[0020] The outer casing 2 comprises an internal cavity. The electrode stack is arranged in the internal cavity. The cell 1 comprises an electrolyte arranged in the internal cavity.

[0021] The cell 1 includes a cover 4. The cover 4 is an added part. The cover 4 is arranged on the outer casing 2 so as to close the internal cavity.

[0022] The cell 1 includes a junction 5 between the cover 4 and the outer casing 2. The junction 5 is defined as the line or contact area between the cover 4 and the outer casing 2.

[0023] Cell 1 includes a hydrophobic zone 6 which covers the junction 5 and extends on either side of said junction 5.

[0024] In other words, the hydrophobic zone 6 completely covers the junction 5, along a longitudinal X axis of extension of the junction 6, and extends beyond said junction 6 along a transverse Y axis perpendicular to the longitudinal X axis.

[0025] Thus, the hydrophobic zone 6 is protected from corrosion. In the absence of such a hydrophobic zone 6, the junction 5 and the surrounding area are susceptible to corrosion, thereby weakening the structure of the outer casing 2. An electrolyte leak may occur.

[0026] Advantageously, the outer casing 2 comprises an outer face 7 having a coating containing Nickel.

[0027] Such a coating provides anti-corrosive properties. Thus, the outer casing 7 is protected from corrosion.

[0028] Advantageously, the cover 4 includes an external face 8 having a coating containing Nickel.

[0029] Such a coating provides anti-corrosive properties. Thus, the cover 4 is protected from corrosion.

[0030] Advantageously, the cell 1 includes a fixing weld 9 affixed to the junction 5 between the cover 4 and the outer casing 2. The fixing weld 9 secures the cover 4 to the outer casing 2.

[0031] The hydrophobic zone 6 completely covers the weld 9 along the X axis and along the Y axis. The hydrophobic zone 6 extends beyond the weld 9. Thus the hydrophobic zone 6 extends from the cover 4 to the outer casing 2.

[0032] Due to the temperatures used to apply the weld 9, the nickel coatings on the cover 4 and the outer casing 2 are damaged or even destroyed. The hydrophobic zone 6 protects the weld and the immediate vicinity of said weld 9 from corrosion.

[0033] Advantageously, the weld 9 comprises a proximal edge 10 located on one side of the junction 5 and a distal edge 11 opposite to the proximal edge 10 and located on the other side of the junction 5.

[0034] The hydrophobic zone 6 has an upper edge 12 located on the side of the junction 5 where the proximal edge 10 is located and a lower edge 13 opposite the upper edge 12 and located on the side of the junction where the distal edge 11 is located.

[0035] The upper edge 12 is located at a first predetermined distance 14 from the proximal edge 10.

[0036] The lower edge 13 is located at a second predetermined distance 15 from the distal edge 11.

[0037] The first distance 14 and the second distance 15 are measured along a shortest path.

[0038] This helps to protect weld 9 and its surrounding area.

[0039] Advantageously, the first distance 14 is at least equal to 1 millimeter.

[0040] This helps to protect the weld 9 and its surrounding area on the side of the cover 4.

[0041] Advantageously, the second distance 15 is at least equal to 1 millimeter.

[0042] This helps to protect the weld 9 and its surrounding area on the side of the casing 2 exterior.

[0043] Advantageously, the first distance 14 and the second distance 15 are substantially equal.

[0044] This simplifies the manufacturing of cell 1 and speeds up production rates.

[0045] Advantageously the hydrophobic zone 6 has an external surface 16 having a microstructure allowing contact with an external liquid at an angle greater than or equal to 150°.

[0046] This makes it possible to create the conditions in which the liquid cannot corrode the hydrophobic zone 6.

[0047] Advantageously the invention relates to a method 17 for manufacturing a cell 1.

[0048] The process 17 comprises: - an operation 01 of supplying a sheet of a first electrode, - an operation 02 of supplying a sheet of a first insulating separator, - an operation 03 of supplying a sheet of a second electrode, - an operation 04 of supplying a sheet of a second insulating separator, - an operation 05 of successively stacking the first electrode, the first insulating separator, the second electrode, the second insulating separator so as to form a stack, - an operation 06 of winding the stack onto itself, - an operation 07 for supplying an outer casing comprising an internal cavity, - an operation 08 involving the insertion of the winding into the internal cavity, - an operation 09 of supplying a cover so as to close the internal cavity.

[0049] The method includes an operation 010 of structuring the outer surface 16 of the outer envelope 2 and of the cover 4 on the junction 5 and around the junction 5 so as to form a hydrophobic zone 6 which extends on either side of the junction 5.

[0050] Thus, junction 5 and its surroundings are protected from corrosion. In the absence of such a hydrophobic zone 6, junction 5 and the surrounding area are susceptible to corrosion, thereby weakening the structure of the outer casing 2. An electrolyte leak may occur.

[0051] Advantageously, the method 17 includes a welding operation 011. The welding operation 011 is carried out so as to perform a fixing weld 9 on the junction 5 between the cover 4 and the outer casing 2.

[0052] The welding operation 011 is carried out before the structuring operation O10.

[0053] Thus the hydrophobic zone 6 completely covers the weld 9 and extends beyond said weld 9. The hydrophobic zone 6 makes it possible to cover this area where Nickel is lacking due to the welding operation 011.

[0054] Advantageously, the structuring operation O10 is carried out so that the hydrophobic zone 6 has an external surface 16 having a microstructure allowing contact with an external liquid at an angle greater than or equal to 150°.

[0055] This makes it possible to create the conditions in which the liquid cannot corrode the hydrophobic zone 6.

[0056] Advantageously the O10 structuring operation is carried out so as to ablate material.

[0057] The material is removed so as to form reliefs allowing contact with an external liquid at an angle greater than or equal to 150° as previously mentioned.

[0058] This method is effective and allows for the optimization of production costs.

Claims

Demands

1. Electric battery cell (1) for an electric propulsion vehicle, said cell (1) comprising a stack of electrodes separated from each other by a porous separator film, the cell 1 comprising: - an outer casing (2) defining an internal cavity in which the stack is arranged, - an electrolyte arranged in the internal cavity, - a cover (4), attached and arranged so as to close the internal cavity, said cell (1) comprising a junction (5) between the cover (4) and the outer casing (2), said cell (1) comprising a hydrophobic zone (6), said hydrophobic zone (6) covering the junction (5) and extending on both sides of the junction (5).

2. Cell (1) according to claim 1 wherein it comprises a fixing weld (9) on the joint (5), said fixing weld (9) being intended to secure the cover (4) to the outer envelope (2), cell (1) wherein the hydrophobic zone (6) fully covers the weld (9) and extends beyond the weld (9).

3. Cell (1) according to claim 2 in which: - the weld (9) has a proximal edge (10) located on one side of the junction (5) and a distal edge (11) opposite the proximal edge (10) and located on the other side of the junction (5), - the hydrophobic zone (6) has a superior edge (12) located on the side of the junction (5) where the proximal edge (10) is located and a inferior edge (13) opposite the superior edge (12) and located on the side of the junction (5) where the distal edge (11) is located, cell in which: - the superior edge (12) is located at a first predetermined distance (14) from the proximal edge (10), - the inferior edge (13) is located at a second predetermined distance (15) from the distal edge (11).

4. Cell (1) according to claim 3 in which the first distance (14) is at least equal to 1 millimeter.

5. Cell (1) according to any one of claims 3 or 4 wherein the second distance (15) is at least equal to 1 millimeter.

6. Cell (1) according to any one of claims 3 to 5 wherein the first distance (14) and the second distance (15) are substantially equal.

7. Cell (1) according to any one of the preceding claims in which, the outer casing (2) comprises an outer face (7) having a coating containing Nickel.

8. Cell (1) according to any one of the preceding claims in which, the cover (4) comprises an external face (8) having a coating containing Nickel.

9. Cell (1) according to any one of the preceding claims, wherein the hydrophobic zone (6) has an outer surface (16) having a microstructure allowing contact with an external liquid at an angle greater than or equal to 150°

10. A method (17) for manufacturing a cell according to any one of claims 1 to 9, comprising: - an operation (01) of supplying a sheet of a first electrode, - an operation (02) of supplying a sheet of a first insulating separator, - an operation (03) of supplying a sheet of a second electrode, - an operation (04) of supplying a sheet of a second insulating separator, - an operation (05) of successively stacking the first electrode, the first insulating separator, the second electrode, and the second insulating separator so as to form a stack, - an operation (06) of winding the stack onto itself, - an operation (07) of supplying an outer casing comprising an internal cavity, - an operation (08) of inserting the winding into the internal cavity of the outer casing, - an operation (09) of supplying a cover so as to close the internal cavity,the cell (1) comprising a junction between the lid (4) and the outer casing (2), the method (1) comprising a structuring operation (010) so as to form a hydrophobic zone (6) extending on either side of the junction (5).

11. Method (17) according to claim 10 wherein it comprises a welding operation (011) so as to perform a fixing weld (9) on the joint (5) to secure the cover (4) to the outer casing (2), said welding operation (011) being prior to the structuring operation (O10) and said structuring operation (O10) being performed so that the hydrophone zone (6) fully covers the weld (9) and extends beyond said weld (9).

12. A method (17) according to any one of claims 10 or 11 wherein the structuring operation (O10) is carried out so as to create a hydrophobic zone (6) in which the outer surface (16) has a microstructure allowing contact with an external liquid at an angle greater than or equal to 150°.

13. Method (17) according to any one of claims 10 to 12 wherein the structuring operation (010) is carried out so as to ablate material.

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