Electrochemical cell for electric battery and electric vehicle battery

Abstract

An electrical cell (1) comprising: - a hermetically sealed flexible bag (2), - a plurality of positive and negative electrodes (3, 4) separated from each other by a porous separator film (5) so as to form a stack (6) of electrodes, said stack (6) of electrodes being enclosed in the flexible bag (2), - an electrolyte arranged in the flexible bag (2), - a first terminal (7) connected to the positive electrodes (3) and a second terminal connected to the negative electrodes (4), said first and second terminals protruding from the flexible bag (2), the cell (1) comprising a rigid outer shell (9) in which the flexible bag (2) is arranged, said outer shell (9) comprising: - a first metallic portion (10) connected to the first terminal (7) and, - a second metallic portion (11) connected to the second terminal. Figure for the abbreviation: Figure 2

Description

Title of the invention: Electrochemical cell for electric battery and electric vehicle battery. Technical field of the invention

[0001] The invention relates to the field of electric vehicle batteries. In particular, the invention relates to electric battery cells. More precisely, the invention relates to electric cells comprising an assembly of electrodes encased in a flexible bag and fitted with a rigid outer shell. The invention further relates to batteries for electric vehicles comprising such electric cells. Technical background

[0002] Electric motor vehicles are equipped with electric batteries to provide the energy needed for propulsion.

[0003] These electric batteries comprise several electrical modules, each containing electrical cells. Within a given module, the electrical cells are electrically interconnected. The electrical modules are electrically interconnected and, together with other electrical components, form the battery of the electric vehicle.

[0004] Electrical connections are made using added metal parts, known by the Anglo-Saxon term "busbar". These electrical connections are obtained by welding the metal parts onto the cells at the module level, and between modules at the battery level.

[0005] The modules have a substantially parallelepiped shape. They are metal boxes in which the electrical cells are arranged and are electrically interconnected with each other.

[0006] Although the architecture of automotive vehicle batteries is generally satisfactory, it can still be improved.

[0007] Indeed, the modules significantly complicate this architecture.

[0008] One disadvantage of the modules is that they add weight to the battery due to the many metal parts they contain, which makes the vehicle more energy-intensive and reduces the performance of electric vehicles.

[0009] Another disadvantage of the modules is that they reduce the volume available for possible additional cells, which reduces the battery power of the electric vehicle.

[0010] Another disadvantage of the modules is that they increase the manufacturing cost of the battery and consequently of the electric vehicle.

[0011] Another disadvantage of the current architecture of electric batteries is that they are particularly tedious to assemble due to the number of welds required to manufacture each module on the one hand and to assemble the modules together on the other hand, which increases manufacturing times and increases the cost of the electric vehicle.

[0012] Another drawback of the current architecture of electric batteries is their low level of repairability. Indeed, when a cell is defective, the module containing it must be replaced.

[0013] Another drawback of the current architecture of electric batteries lies in the difficulty of recycling. The modules, which include many welded metal parts, do not allow for rapid and inexpensive recycling to achieve high purity levels. In order to achieve these high purity levels, complex and therefore expensive recycling processes are used.

[0014] The invention aims to improve electric batteries equipped with flexible bag cells. Summary of the invention

[0015] To this end, an electrical cell is proposed firstly, comprising: - a flexible, airtight bag, - a plurality of positive and negative electrodes separated from each other by a porous separator film so as to form a stack of electrodes, said electrode stack being wrapped in the flexible bag, - an electrolyte arranged in the flexible bag, - a first terminal connected to the positive electrodes and a second terminal connected to the negative electrodes, said first and second terminals protruding from the flexible bag, the cell comprising a rigid outer shell in which the flexible bag is arranged, said outer shell comprising: - a first metallic portion connected to the first terminal and, - a second metallic portion connected to the second terminal, cell in which the first metallic portion and the second metallic portion are electrically isolated from each other.

[0016] The cells can be arranged directly in a battery, side by side. Thanks to the terminals, the cells can be interconnected within a battery. Thus, it is no longer necessary to use added metal elements to interconnect the cells. There may be an exception for cells located at the ends of the battery.

[0017] Thus this cell makes it possible to do without the modules.

[0018] The rigid outer shell protects the flexible pouch and provides precise dimensions for the cell, thus facilitating battery manufacturing. Furthermore, the outer shell provides structural rigidity to the electric battery and therefore to the electric car. Indeed, the electric battery is generally an integral part of the electric vehicle's chassis and contributes to the mechanical strength of the structure.

[0019] The battery is lighter, a greater number of cells can be arranged within it, the battery is easier to manufacture, notably by reducing the number of operations, and the overall performance of the battery and the vehicle is improved. The manufacturing cost is also reduced.

[0020] Furthermore, when a cell is defective, it is simpler to replace only the said defective cell.

[0021] Furthermore, recycling is improved because the number of welds likely to cause metal mixing is significantly reduced. This facilitated recycling also makes it possible to obtain higher purity levels.

[0022] Various additional features may be provided alone or in combination: - the electrodes are distinct from each other and said electrodes are separated from each other by a porous separating film, said electrodes being stacked along a stacking axis; - the stack of electrodes has a substantially parallelepiped shape, said stack having a first face and a second face opposite the first face and four lateral slices connecting the first face to the second face and extending laterally along the stacking axis, said first and second face each having a surface area greater than the surface area of ​​each of the slices taken individually, the first terminal protruding from a first slice and the second terminal protruding from a second slice opposite the first slice, cell in which the first metallic portion is arranged opposite the first face and the second metallic portion is arranged opposite the second face; - the outer shell includes a housing in which the stack of electrodes is arranged; - The outer shell includes: - a first part comprising the first metallic portion and the first means of fastening, - a second part distinct from the first part, said second part comprising the second metallic portion and second fastening means intended to cooperate with the first fastening means so as to encapsulate the flexible bag comprising the stack of electrodes; - the first part and the second part of the outer hull have in section roughly a U or V shape with a flat bottom; - The first and second parts of the outer shell comprise: - a main wall on which the first and second metal sections are respectively arranged, and - a skirt forming an angle with the main wall, said skirt including the means of attachment; - the cell includes a thermal paste arranged in a first space located between a slice and the outer shell, said thermal paste being in contact with said at least one slice and said outer shell; - the slices of the electrode stack are arranged approximately opposite the skirt of the outer shell; - the skirt is made of an electrically insulating material; - the skirt is made of a thermally conductive material; - the skirt and the main wall of the first part and the second part respectively are made in one piece; - the first part and the second part of the outer shell are manufactured by overmolding respectively on the first metal portion and on the second metal portion; - the cell includes a thermal insulating element arranged inside the outer shell, said thermal insulating element being capable of thermally insulating the flexible bag from the outer shell; - the thermal insulation element is arranged between at least one main wall and the flexible bag.

[0023] Secondly, an electric battery is proposed comprising a plurality of cells as previously described, said cells being arranged next to each other so that the first metallic portion of a given cell is in direct contact with the second metallic portion of another immediately adjacent cell.

[0024] In one embodiment, the electric battery shown above does not include an electrical module. Brief description of the figures

[0025] 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:

[0026] [Fig-1] [Fig.1] is a schematic representation of a cell according to the invention;

[0027] [Fig.2] [Fig.2] is viewed according to section plane II-II of [Fig.1];

[0028] [Fig.3] [Fig.3] is viewed according to section plane III-III of [Fig.1];

[0029] [Fig.4] [Fig.4] is a schematic representation of a battery comprising cells according to the invention. Detailed description of the invention

[0030] The drawings show an electrical cell 1. Electrical cells 1 are intended to be integrated into an electric vehicle.

[0031] Cell 1 comprises a flexible pouch 2. Cell 1 has several positive and negative electrodes 3, 4 separated from each other by a porous separator film 5. The electrodes 3, 4 and the separator films 4 together form a stack 6 of electrodes.

[0032] The stack of 6 electrodes is arranged in the flexible bag 2. Thus, the flexible bag 2 encloses the stack of 6 electrodes.

[0033] Cell 1 comprises an electrolyte which is arranged in the flexible sachet 2.

[0034] The flexible bag 2 is airtight. By "airtight", it is understood that the bag 2 The flexible pouch is leak-proof in that it isolates the stack of 6 electrodes and the electrolyte. Therefore, no electrolyte leakage outside the flexible pouch is possible, and no external contamination can enter the flexible pouch.

[0035] Cell 1 comprises a first terminal 7 electrically connected to the positive electrodes 3. Cell 1 comprises a second terminal 8 electrically connected to the negative electrodes 4. As can be seen in [Fig. 3], the first terminal 7 and the second terminal 8 protrude from the flexible pouch 2.

[0036] Cell 1 comprises a rigid outer shell 9. The flexible pouch 2 is arranged in the outer shell 9.

[0037] The outer shell 9 includes a first metallic portion 10 electrically connected to the first terminal 7. The outer shell 9 includes a second metallic portion 11 connected to the second terminal 8. The first metallic portion 10 and the second metallic portion 11 are electrically isolated from each other.

[0038] The cells 1 can be arranged directly in a battery 12, side by side. Thanks to the terminals 7 and 8, the cells can be interconnected within a battery. Thus, it is no longer necessary to use added metal elements to interconnect the cells 1. There may be an exception for cells located at the ends of the battery 12.

[0039] Thus this cell 1 makes it possible to do without the modules.

[0040] The rigid outer shell 9 protects the flexible pouch and gives precise dimensions to the cell 1, which facilitates battery manufacturing. Furthermore, the outer shell 9 provides structural rigidity to the electric battery 1 and therefore to the electric car. Indeed, the electric battery is generally an integral part of the chassis of the electric vehicle and contributes to the mechanical strength of the structure.

[0041] The battery 12 is lighter, a greater number of cells 1 can be arranged in it, the battery 12 is easier to manufacture, notably by reducing the number of operations, and the overall performance of the battery 12 and the vehicle is improved. The manufacturing cost is also reduced.

[0042] Furthermore, when a cell is defective, it is simpler to replace only the said defective cell.

[0043] Furthermore, recycling is improved because the number of welds likely to cause metal mixing is significantly reduced. This facilitated recycling also makes it possible to obtain higher purity levels.

[0044] Advantageously, the electrode stack 6 comprises electrodes 3, 4 that are distinct from one another. By "distinct," it is understood that the electrodes 3, 4 are cut to form portions. Once cut, the electrodes 3, 4 are stacked one on top of the other, along a stacking axis X, separated from each other by a porous separator film 5, to form the electrode stack 6.

[0045] These cells 1 are particularly suitable for use in electric motor vehicles.

[0046] Advantageously, the electrode stack 6 has a substantially parallelepiped shape. The stack 6 comprises a first face 13, a second face 14 opposite the first face 13, and four lateral slices 15, 16, 17 connecting the first face 13 to the second face 14. The slices 15, 16, 17 extend along the stacking X-axis. Conversely, the first face 13 and the second face 14 do not extend along the stacking X-axis.

[0047] The first face 13 has a surface substantially identical to the second face 14. Each slice has a surface substantially identical. The surface of the first face 13 or the second face 14 is greater than the surface of any of the lateral slices 15, 16, 17.

[0048] The first terminal 7 protrudes from a first slice 15 and the second terminal 8 protrudes from a second slice 16 opposite the first slice 15.

[0049] The first metallic portion 10 is arranged opposite the first face 13 and the second metallic portion 11 is arranged opposite the second face 14.

[0050] Thus, the cells 1 can be electrically connected to each other in the battery by bringing their largest surface areas into contact. This provides stability and mechanical robustness to the assembly and facilitates the assembly of the cells 1 in the battery 12.

[0051] Advantageously, the outer shell 9 has a housing 18. The stack 6 of electrodes is arranged in the housing 18. The housing 18 has a shape which is substantially a counter impression of the stack 6 of electrodes.

[0052] This prevents the stack of electrodes 6 from moving in cell 1. During the manufacture of cell 1, assembly is facilitated.

[0053] Advantageously, the outer shell 9 comprises a first part 19 and a second part 20 distinct from the first part 19. The first part 19 comprises the first metallic portion 10, and the second part 20 comprises the second metallic portion 11.

[0054] The first part 19 includes first means 21 for fixing and the second part 20 includes second means 22 for fixing intended to cooperate with the first means 21 for fixing to encapsulate the stack 6 of electrodes.

[0055] The first means 21 of fixing are, for example, in the form of mounting tabs and the second means 22 of fixing are holes suitable for receiving the mounting tabs.

[0056] Such an architecture allows a simplified assembly of the first part 19 and the second part 20.

[0057] As can be seen in [Fig.2], the first part 19 and the second part 20 of the outer shell 9 have in section a U shape with a flat bottom.

[0058] Alternatively, the first part 19 and the second part 20 of the outer hull 9 may have a flat-bottomed V shape in section.

[0059] These shapes are simple to manufacture and provide good mechanical strength to the outer shell 9.

[0060] Advantageously, the first part 19 comprises a first main wall 23 and a first skirt 24 forming an angle with the first main wall 23. The first metallic portion 10 is arranged on the first main wall 23.

[0061] The second part comprises a second main wall 25 and a second skirt 26 forming an angle with the second main wall 25. The second metallic portion 11 is arranged on the second main wall 25.

[0062] The first skirt 24 includes the first fastening means 21. The second skirt 26 includes the second fastening means 22.

[0063] In the embodiment shown in the drawings, the skirt 24, 26 forms a substantially right angle with the main wall 23, 25.

[0064] These shapes are simple to manufacture and give good mechanical strength to the outer shell 9.

[0065] Advantageously, the cell 1 includes a thermal paste (not shown in the drawings). The thermal paste is arranged in a first space 27 located between a lateral slice 15, 16, 17 of the electrode stack 6 and the outer shell 9. The paste thermal is in contact with the lateral slice 15,16, 17 on one side and with the outer shell 9 on the other.

[0066] Thus, by cooling the outer shell 9, it becomes possible to cool the electrode stack 6, particularly at the lateral edge 15, 16, 17. Cooling at the lateral edge 15, 16, 17 allows for precise thermal management of the cell 1. Indeed, at the lateral edge 15, 16, 17, it becomes possible to thermally control all the electrodes 3, 4.

[0067] Advantageously, the lateral slices 15, 16, 17 are arranged opposite the skirt 24, 26 of the outer hull 9.

[0068] The skirt 24, 26 is the most accessible part of the outer shell 9 for thermal management in the battery. Since the main walls 23, 25 of the cells 1 are in close contact with each other, it is easier to achieve thermal management at the level of the skirt 24, 26.

[0069] Advantageously, the skirt 24, 26 and the main wall 23, 25 are made of an electrically insulating material.

[0070] This allows the first metallic portion 10 and the second metallic portion 11 to be electrically isolated from each other without the addition of additional insulating elements.

[0071] Advantageously, the skirt 24, 26 is made of a thermally conductive material.

[0072] This allows for good thermal management of the 6-electrode stack.

[0073] Advantageously, the main wall 23, 25 and the skirt 24, 26 of each part 19, 20 are manufactured in one piece.

[0074] Thus it is possible to manufacture them at low cost, simply and in large series, in particular by molding.

[0075] Advantageously the first metallic portion 10 is manufactured by overmolding on the first part 19. The second metallic portion 11 is manufactured by overmolding on the second part 20.

[0076] Thus, the outer shell 9 is particularly robust.

[0077] Advantageously, the cell includes a thermal insulation element. The thermal insulation element is arranged inside the outer shell 9. The thermal insulation element is arranged in a second space 28 located between the first main wall 23 and the first face 13 of the flexible pouch 2. The thermal insulation element is thus suitable and intended to thermally insulate the flexible pouch 2 from the outer shell 9. More precisely, the thermal insulation element thermally insulates the first face 13 from the first main wall 23.

[0078] In one embodiment, the thermal insulation element can be arranged between the second face 14 of the flexible bag 2 and the second main wall 25.

[0079] Advantageously, the thermal insulation element is arranged between the main wall 23 and the flexible pouch 2. Alternatively, the thermal insulation element is arranged between the main wall 25 and the flexible pouch 2.

[0080] The thermal insulator thus positioned allows each cell to be thermally isolated. In battery 12, it becomes possible to place the cells directly in contact with each other without the temperature of each cell having a significant impact on those immediately adjacent to it. It then becomes possible to improve the thermal management of each cell.

[0081] The thermal insulating element is, for example, an aerogel, cork or mica. Other materials may be used.

[0082] Figure 4 shows a battery 12 comprising the previously described cells 1. The cells 1 are arranged side by side. Thus, the first metallic portion 10 of a given cell 1 is in direct contact with the second metallic portion 11 of another immediately adjacent cell 1.

[0083] As can be seen, an electric vehicle battery 12 is manufactured directly from cells 1 and this without any electrical module.

Claims

Demands

1. An electrical cell (1) comprising: - a hermetically sealed flexible pouch (2), - a plurality of positive and negative electrodes (3, 4) separated from each other by a porous separator film (5) so as to form a stack (6) of electrodes, said stack (6) of electrodes being enclosed in the flexible pouch (2), - an electrolyte arranged in the flexible pouch (2), - a first terminal (7) connected to the positive electrodes (3) and a second terminal (8) connected to the negative electrodes (4), said first and second terminals (8, 9) projecting from the flexible pouch (2), the cell (1) comprising a rigid outer shell (9) in which the flexible pouch (2) is arranged, said outer shell (9) comprising: - a first part (19) and a second part (20) distinct from the first part (19), the first part (19) comprising a first main wall (23) and a first skirt (24) forming an angle with the first main wall (23),the second part (20) comprising a second main wall (25) and a second skirt (26) forming an angle with the second main wall (25); - a first metallic portion (10) connected to the first terminal (7), this first metallic portion (10) being arranged on said first main wall (23); - a second metallic portion (11) connected to the second terminal (8), this second metallic portion (11) being arranged on said second main wall (25); cell (1) in which each of the first skirt (24) and the second skirt (26) is made of an electrically insulating material such that the first metallic portion (10) and the second metallic portion (11) are electrically insulated from each other.

2. Electrical cell (1) according to claim 1 in which the electrodes (3, 4) are distinct from each other and said electrodes (3, 4) are separated from each other by a porous separator film (5), said electrodes (3, 4) being stacked along a stacking axis (X).

3. Electrical cell (1) according to claim 2, wherein the stack (6) of electrodes has a substantially parallelepiped shape, said stack (6) having a first face (13) and a second face (14) opposite the first face (13), and four lateral slices (15, 16, 17) connecting the first face (13) to the second face (14) and extending laterally along the stack axis (X), said first and second faces (13, 14) each having a surface area greater than the surface area of ​​each of the slices (15, 16, 17) taken individually, the first terminal (7) projecting from a first slice (15) and the second terminal (8) projecting from a second slice (16) opposite the first slice (15), cell (1) wherein the first metallic portion (10) is arranged opposite the first face (13) and the second metallic portion (11) is arranged opposite the second face (14).

4. Electric cell (1) according to any one of the preceding claims in which the outer shell (9) comprises a housing (18) in which the stack (6) of electrodes is arranged.

5. Electrical cell (1) according to claim 4 in which, - the first part (19) comprises first means (21) of fixation, - the second part (20) comprises second means (22) of fixation intended to cooperate with the first means (21) of fixation so as to encapsulate the flexible bag (2) comprising the stack (6) of electrodes.

6. Electrical cell (1) according to any one of the preceding claims in which the first part (19) and the second part (20) of the outer shell (9) have in section substantially a U or V shape with a flat bottom.

7. Electrical cell (1) according to claim 5 in which the first skirt (24) comprises the first means (21) of attachment, and the second skirt (26) comprises the second means (22) of attachment.

8. Electrical cell according to claim 3 or any one of claims 4 to 7 further dependent on claim 3 wherein it comprises a thermal paste arranged in a first space (27) located between a slice (15, 16, 17) and the outer shell (9), said thermal paste being in contact with said at least one slice (15, 16, 17) and said outer shell (9).

9. Electrical cell (1) according to claim 8 in which the slices (15, 16, 17) of the stack (6) of electrodes are arranged substantially opposite the first and second skirt (24, 26) of the outer shell (9).

10. Electrical cell (1) according to any one of the preceding claims wherein each of the first skirt (24) and the second skirt (26) is made of a thermally conductive material.

11. Electrical cell (1) according to any one of the preceding claims in which the skirt (24, 26) and the main wall (23, 25) respectively of the first part (19) and of the second part (20) are made in one piece.

12. Electrical cell (1) according to the preceding claim in which the first part (19) and the second part (20) of the outer shell (9) are manufactured by overmolding respectively on the first metallic portion (10) and on the second metallic portion (11).

13. Electric cell (1) according to any one of the preceding claims, this comprising a thermal insulating element arranged inside the outer shell (9), said thermal insulating element being capable of thermally insulating the flexible bag (2) from the outer shell (9).

14. Electrical cell (1) according to the preceding claim in which the thermal insulating element is arranged between at least one main wall (23, 25) and the flexible bag (2).

15. Electric battery (12) comprising a plurality of cells (1) according to any one of the preceding claims, said cells (1) being arranged next to each other so that the first metallic portion (10) of a given cell (1) is in direct contact with the second metallic portion (11) of another immediately adjacent cell (1).

16. Electric battery (12) according to the preceding claim, wherein it does not include an electrical module.

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