Accumulator cell with optimized arrangement

Abstract

Cell for accumulator with optimized arrangement The invention relates to a cell (1) for accumulator comprising a pocket (11) inside which electrodes (2) and separator films (3) are arranged in the form of: a plurality of substantially planar electrodes (2), positive and negative, arranged alternately in two respective groups determined by polarity, each comprising a respective contact tab (21) arranged at one of the ends of the electrodes (2), planar separator films (3) positioned between each of the electrodes (2), characterized in that the respective contact tabs (21) of the electrodes (2) pass through the thickness of the pocket (11) and are folded against it,so that the contact tabs (21) of the positive electrodes (2) are at an external surface (111) of the pocket (11) opposite the external surface (112) against which the contact tabs (21) of the negative electrodes (2) are folded. Figure to be published with the abstract: Fig.2,

Description

Title of the invention: Accumulator cell with optimized arrangement

[0001] The present invention relates to the field of electric accumulators and more particularly to the field of electric accumulators for vehicles.

[0002] During their construction, electric accumulators are produced in the form of a set of individual electric cells assembled inside a housing block, so that these different cells are connected to each other by means of respective terminals to store and restore electrical energy. These cells inside the housing block are thus individually produced in the form of a flattened arrangement comprising at one of their ends a pair of tabs in the flat extension of the body of the cell.

[0003] forming respective connection terminals. The connection of these different cells to each other is thus carried out, by a series assembly, by means of these tabs forming respectively positive and negative connection elements for each of the cells.

[0004] These tabs at the ends of the cells thus have the shape of two protrusions which protrude from the body of the cell to interact with homologous tabs of juxtaposed cells. However, even inside a housing block, such tabs are structurally elements of fragility compared to the rest of the body of the cells. Indeed, in the event of an impact, the risk of a break at the junction between the tab and the body of the cell is likely to occur. Furthermore, it should be noted that, inside the housing block, the portion of the housing occupied by the pair of tabs in the extension of the body of the cell is then not dedicated to storing electrical energy but is solely intended for connecting the cells together.

[0005] The present invention aims to overcome these drawbacks by proposing a solution which limits the risks of vulnerability of the cells positioned inside a housing block, while making it possible to optimize the volume dedicated to the storage of electrical energy inside a housing block for these cells.

[0006] The invention relates to a cell for an accumulator comprising a pouch inside which electrodes and separator films are arranged in the form of: - a plurality of substantially planar electrodes, on the one hand, positive and, on the other hand, negative, arranged alternately and forming two respective groups determined by their polarities, each of the groups of electrodes comprising a respective contact tab arranged at one of the ends of the electrodes, - flat separator films positioned between each of the electrodes, characterized in that the respective contact tabs of the electrodes pass through the thickness of the pouch and are folded on either side of said pouch, so that the folded contact tabs of the positive electrodes are positioned at an external surface of the pouch opposite another external surface at which the contact tabs of the negative electrodes are folded.

[0007] The invention also relates to an accumulator block comprising a casing, characterized in that the block comprises at least two cells according to the invention housed inside the casing so as to be juxtaposed parallel to each other and held in compression, so that, on the one hand, the folded contact tabs of the positive electrodes of a first cell are in electrical contact with a positive terminal block and that, on the other hand, the folded contact tabs of the negative electrodes of a second cell are in electrical contact with a negative terminal block, the at least two cells being connected in series between the two terminal blocks, positive and negative, of the accumulator block.

[0008] The invention will be better understood from the following description, which relates to preferred embodiments, given as non-limiting examples, and explained with reference to the appended schematic drawings, in which:

[0009] [Fig.l] represents a schematic illustration of an example of grouping of electrodes and separator films in a cell according to the invention,

[0010] [Fig.2] represents a schematic illustration of an example of an arrangement of a contact tab against a surface of a pocket of electrodes and separator films in a cell according to the invention,

[0011] [Fig.3] represents a schematic illustration of an example of folding of a contact tab against a surface of a pocket of electrodes and separator films in a cell according to the invention,

[0012] [Fig.4] represents a schematic illustration of an example of an arrangement of a electrode contact tab associated with a reinforcement in a cell according to the invention,

[0013] [Fig.5] represents a schematic illustration of an example of an arrangement of a envelope end for a cell according to the invention,

[0014] [Fig.6] represents a schematic illustration of an example of assembly of envelope elements with a pocket of electrodes and separator films for a cell according to the invention,

[0015] [Fig.7] represents a schematic illustration of an example of assembly of cells for an accumulator block according to the invention,

[0016] [Fig.8] represents a schematic illustration of an example of assembly of cells and compression elements in a casing for producing an accumulator block according to the invention,

[0017] [Fig.9] represents a schematic illustration of an example of an accumulator block according to the invention.

[0018] The present invention relates to a cell 1 for an accumulator comprising a pouch 11 inside which electrodes 2 and separator films 3 are arranged in the form of: - a plurality of substantially planar electrodes 2, on the one hand, positive and, on the other hand, negative, arranged alternately and forming two respective groups determined by their polarities, each of the groups of electrodes 2 comprising a respective contact tab 21 arranged at one of the ends of the electrodes 2, - 3-plane separator films positioned between each of the electrodes 2, characterized in that the respective contact tabs 21 of the electrodes 2 pass through the thickness of the pocket 11 and are folded on either side of said pocket 11, so that the folded contact tabs 21 of the positive electrodes 2 are positioned at an external surface 111 of the pocket 11 opposite another external surface 112 at which the contact tabs 21 of the negative electrodes 2 are folded.

[0019] By being folded against the external surfaces 111, 112 of the pouch 11 which envelops the electrodes 2 and separator films 3, these flat tabs 21 are pressed against the external surface 111, 112 of the cell 1 so as to eliminate any vulnerable portion at the junction between the tabs 21 and the rest of the cell 1. In fact, each of the tabs 21 and their respective junctions with the body of the cell 1 fits the external surface 111, 112 of the cell 1 so as to limit the presence of roughness or surface variations likely to increase the risk of tearing or degradation of the tab 21 relative to the rest of the structure of the cell 1.In addition, the folding of the respective tabs 21 of the positive and negative electrodes at the level of different and opposite surfaces 111, 112 of the pocket 11 of cell 1 allows in particular a series mounting of several homologous cells 1 according to the invention juxtaposed.

[0020] Furthermore, it should be noted that the folding of the flat tabs 21 against the external surfaces 111, 112 of the pocket 11 of the cell 1 makes it possible to restrict or even eliminate the portion dedicated to the tabs in the length of the cell 1. Thus, inside the housing produced by an accumulator block 9, the cell 1 of the invention is able to comprise a body whose external surface is produced by the pocket 11 which has a greater length, so as to occupy the space left vacant by the various folded tabs 21. Thus, the folding of the tabs 21 against the external surfaces 111, 112 of the pocket 11 allows the construction of cells 1 in which the part intended for the storage of electrical energy is larger than in the cells of the prior art, while allowing the installation of these cells 11 with greater storage capacity in existing accumulator blocks 9.

[0021] It should be noted that, inside the pocket 11, the various electrodes 2 and 3-plane separator films are likely to correspond to electrodes 2 and separator films 3 of known type. The electrodes 2 are thus likely to be made, for example, from graphite for the negative polarity electrode and from a lithium-ionized nickel manganese and cobalt oxide for the positive polarity electrode. Similarly, these electrodes 2 are likely to be associated with one or more liquid or solid electrolytes, inside the cell 1.

[0022] According to an example corresponding to a construction variant capable of being combined with the previously detailed construction method, at least one insulator 4 is arranged between the folded electrode contact tabs 21 2 and the corresponding surfaces 111, 112 of the pocket 11. This insulator 4 provides an interface between the surface of the tab 21 and the corresponding surface 111, 112 of the pocket 11, so as to avoid a parasitic electrical connection between the tab 21 and the surface 111, 112 of the pocket 11. This insulator 4 thus has a surface with dimensions at least greater than the dimensions of the surface of the folded tab 21 capable of bearing against the corresponding surface 111, 112 of the pocket 11. By way of example, this insulator 4 is capable of being made of polymer, Teflon, acrylonitrile butadiene styrene also called ABS.

[0023] According to an example corresponding to another construction variant also capable of being combined with each of the previously detailed variants, the electrodes 2 have substantially rectilinear and similar planar shapes with respective contact tabs 21 at the end so that, in the arrangement of electrodes 2 and separator films 3, the contact tab 21 of the positive electrodes 2 is positioned at an end opposite that of the contact tab 21 of the negative electrodes 2. According to this construction example, the positioning of the contact tabs 21 at the respective ends and surfaces of the cell 1 allows a head-to-tail installation of homologous cells 1 according to the invention juxtaposed so that these cells 1 make an electrical connection via one of their tabs 21.This arrangement of the contact tabs 21 at different ends of the cell 1 also allows a juxtaposition of several cells 1 according to an electrical assembly in series inside an accumulator block 9 without a fan distribution phenomenon occurring due to the positioning of the contact tabs 21 at the same end of. cell 1.

[0024] According to another example corresponding to another construction variant also capable of being combined with each of the previously detailed variants, the cell 1 also comprises a sealed envelope 5 inside which the pocket 11 is housed, so that at least on one of its faces, the envelope 5 comprises an orifice 51 closed by a conductive contact interface 52, possibly in association with an insulating frame 53, this orifice 51 and the conductive contact interface 52 being arranged opposite folded contact tabs 21 of respective electrodes 2. According to this construction example, the orifice 51 is heat-sealed at its peripheral edge with the conductive contact interface 52.According to a specific variant, the junction between the edge of the orifice 51 and the conductive contact interface 52 involves an insulating frame 53 made of a material suitable for preventing any parasitic electrical conduction between the conductive contact interface 52 and the surface of the casing 5. Thus, the insulating frame 53, on the one hand, is positioned and sealed along the entire inner edge of the orifice 51 of the casing 5 and, on the other hand, surrounds the periphery of the conductive contact interface 52 in a sealed manner. It should be noted that the inner surface of the conductive contact interface 52 is arranged to be in electrical contact with one of the two electrode contact tabs 21, negative or positive, of the cell 1.Preferably, the casing 5 of the cell 1 comprises two orifices 51 respectively positioned at opposite surfaces so that the conductive contact interfaces 52 associated with each of these orifices are positioned opposite a respective electrode 2 contact tab 21 with which electrical contact is made, so that the outer surface of each conductive contact interface 52 forms the electrical contact surface, negative or positive, of the cell 1 with an element outside the casing 5. The elements positioned inside the casing 5 thus do not make any direct contact with the external elements. The electrical contacts between the positive and negative electrodes 2 of the cell 1 and the outside are made by means of the pair of tabs 21 respectively associated with a conductive contact interface 52.Also, the casing 5 remains completely sealed while allowing electrical exchanges with the exterior at the level of the pair of orifices 51 associated with the respective conductive contact interfaces 52. Thus, the electrical connection between two juxtaposed cells 1 takes place via these conductive contact interfaces 52 carried by respective cells 1 and positioned opposite each other.

[0025] According to another example corresponding to a particular variant of the previously detailed variant, the conductive contact interface 52 which closes the orifice 51 of the envelope 5 comprises an arrangement comprising a relief having a height greater than the thickness of the casing 5 so as to be able to cooperate with a conductive contact interface 52 carried by a juxtaposed homologous cell 1. The electrical conduction between a contact tab 21 of electrodes 2 and the exterior must be carried out through the thickness of the casing 5 at the orifices 51. To ensure a connection of the conductive contact interface 52 at each of its surfaces, it is appropriate that the effective thickness of the conductive contact interface 52 positioned at the orifices 51 is greater than the thickness of the casing 5. Also, at least one of the surfaces of the conductive contact interface 52 comprises a relief, in particular the surface of the conductive contact interface 52 whose periphery is fixed to the orifice 51 of the casing 5.This relief then has a height or thickness suitable for passing through the orifice 51 of the casing 5 and thus allowing effective electrical contact which is able to overcome the thickness of the casing 5.

[0026] According to another example corresponding to another construction variant also capable of being combined with each of the previously detailed variants, the cell 1 comprises at least one contact reinforcement 54 fixed to one of the folded electrode contact tabs 21 and capable of cooperating with the inner surface of a conductive contact interface 52 fixed to the casing 5. This contact reinforcement 54 is made of a conductive material so as not to limit the electrical exchanges between the tab 21 and the conductive contact interface. In addition, this contact reinforcement 54 has a rigidity greater than that of a tab 21 so as to be able to withstand possible mechanical forces under the effect of pressure exerted through the conductive contact interface 52, while preventing the electrode contact tab 21 2 from being subject to any degradation resulting from these mechanical forces.The reinforcement 54 is thus fixed on the surface of the corresponding contact tab 21 prior to positioning the association of the electrodes 2 and separator films 3 inside the envelope 5 of the cell 1.

[0027] According to another example corresponding to another construction variant also capable of being combined with each of the previously detailed variants, the casing 5 is produced by cooperation of two half-shells assembled together by welding on their periphery. The casing 5 having a substantially planar arrangement, each of the half-shells also has a substantially planar arrangement and integrates an orifice 51 associated with a conductive contact interface 52 possibly in association with an insulating frame 53.

[0028] The invention also relates to an accumulator block 9 comprising a casing 91, characterized in that the accumulator block 9 comprises at least two cells 1 according to the invention housed inside the casing 91 so as to be juxtaposed parallel to each other and held in compression, so that, on the one hand, the tab 21 of folded contact of the positive electrodes 2 of a first cell 1 are in electrical contact with a positive terminal block 92 and that, on the other hand, the folded contact tab 21 of the negative electrodes 2 of a second cell 1 are in electrical contact with a negative terminal block 92, the at least two cells 1 being connected in series between the two terminal blocks 92, positive and negative, of the accumulator block 9. By way of example, the casing 91 of the accumulator block 9 is capable of being constructed in the form of two halves of casing 91 which, once assembled, form the housing making it possible to receive the at least two cells 1. Maintaining the cells 1 in compression inside the casing 91 of the accumulator block 9 involves elastic means specifically intended to maintain the position of the cells 1 in support against each other and in electrical contact, in particular at the level of their conductive contact interfaces 52.These elastic means are likely to correspond to compression plates 94 associated with spring elements which operate a clamping by pinching of the cells 1 juxtaposed in contact with each other by their main surfaces.

[0029] The mounting of the cells 1 in series inside the casing 91 of the accumulator block 9 makes it possible to operate a substantially linear electrical junction between the two terminals 92 by the succession of the cells 1. Thus, according to an example corresponding to a construction variant capable of being combined with the construction method detailed previously, the cells 1 having substantially planar arrangements, these cells 1 are juxtaposed inside the casing 91 while being supported by their surfaces, so that, by compression, the folded contact tab 21 of the positive electrodes 2 of a cell 1 is in electrical contact with the folded contact tab 21 of the negative electrodes 2 of another juxtaposed cell 1.

[0030] According to an example corresponding to a construction variant capable of being combined with the construction variant detailed above, at least one connecting bar is positioned as an intermediate contactor at the electrical junction between the folded contact tab 21 of the positive electrodes 2 of a cell 1 and the folded contact tab 21 of the negative electrodes 2 of another cell 1 juxtaposed and connected in series with the first cell 1. This connecting bar is thus capable of mechanically and electrically optimizing the junction between at least two juxtaposed cells 1.Furthermore, due to its elongated shape, the connecting bar is capable of allowing an electrical connection between, on the one hand, the contact tabs 21 of the identical electrodes 2, positive or negative, respective of several cells 1 and, on the other hand, the contact tab 21 of the opposite electrodes 2 of another juxtaposed cell 1.

[0031] According to an example corresponding to a construction variant capable of being combined with each of the different construction methods detailed previously, the cells 1 having substantially planar arrangements, these cells 1 grouped inside the casing 91 of the accumulator block 9 in juxtaposed sets 12, the cells 1 being supported by their respective conductive contact interfaces 52 inside each set 12 and connected in series, so that the contact tab 21 of the positive electrodes 2 of a cell 1 are in electrical contact with the contact tab 21 of the negative electrodes of another juxtaposed cell 1, at least one connection bar being positioned as an intermediate contactor between two pairs of cells 1 respectively arranged in two juxtaposed sets 12. Such a connecting bar thus makes it possible to operate a parallel connection of several cells 1 positioned inside the casing 92 of the accumulator block 9. The two juxtaposed assemblies 12 thus relate to two groups of cells 1 arranged in compression parallel to each other..

[0032] Of course, the invention is not limited to the embodiments described and shown in the attached drawings. Modifications remain possible, in particular from the point of view of the constitution of the various elements or by substitution of technical equivalents, without departing from the scope of protection of the invention.

Claims

Claims

1. Cell (1) for an accumulator comprising a pouch (11) inside which electrodes (2) and separator films (3) are arranged in the form of: - a plurality of substantially planar electrodes (2), on the one hand, positive and, on the other hand, negative, arranged alternately and forming two respective groups determined by their polarities, each of the groups of electrodes (2) comprising a respective contact tab (21) arranged at one of the ends of the electrodes (2), - planar separator films (3) positioned between each of the electrodes (2), characterized in that the respective contact tabs (21) of the electrodes (2) pass through the thickness of the pouch (11) and are folded on either side of said pouch (11),such that the folded contact tabs (21) of the positive electrodes (2) are positioned at an external surface (111) of the pouch (11) opposite another external surface (112) at which the contact tabs (21) of the negative electrodes (2) are folded.,

2. Cell (1) according to claim 1, characterized in that at least one insulator (4) is arranged between the contact tabs (21) of the folded electrodes (2) and the corresponding surfaces (111, 112) of the pocket (H).

3. Cell (1) according to claim 1 or 2, characterized in that the electrodes (2) have substantially rectilinear and similar planar shapes with respective contact tabs (21) at the end so that, in the arrangement of electrodes (2) and separator films (3), the contact tab (21) of the positive electrodes (2) is positioned at an end opposite that of the contact tab (21) of the negative electrodes (2).

4. Cell (1) according to one of claims 1 to 3, characterized in that the cell (1) also comprises a sealed envelope (5) inside which the pocket (11) is housed, so that at least on one of its faces, the envelope (5) comprises an orifice (51) closed by a conductive contact interface (52), possibly in association with an insulating frame (53), this orifice (51) and the conductive contact interface (52) being arranged opposite folded contact tabs (21) of the respective electrodes (2).

5. Cell (1) according to claim 4, characterized in that the conductive contact interface (52) which closes the orifice (51) of the envelope (5) comprises an arrangement comprising a relief having a height greater than the thickness of the envelope (5) so as to be able to cooperate with a conductive contact interface (52) carried by a juxtaposed homologous cell (1).

6. Cell (1) according to one of claims 1 to 5, characterized in that the cell (1) comprises at least one contact reinforcement (54) fixed to one of the folded electrode contact tabs (21) and capable of cooperating with the inner surface of a conductive contact interface (52) fixed to the casing (5).

7. Cell (1) according to one of the preceding claims, characterized in that the envelope (5) is produced by cooperation of two half-shells assembled together by welding on their periphery.

8. Accumulator block (9) comprising a casing (91), characterized in that the accumulator block (9) comprises at least two cells (1) according to one of claims 1 to 7 housed inside the casing (91) so as to be juxtaposed parallel to each other and held in compression, so that, on the one hand, the folded contact tab (21) of the positive electrodes (2) of a first cell (1) are in electrical contact with a positive terminal block (92) and that, on the other hand, the folded contact tab (21) of the negative electrodes (2) of a second cell (1) are in electrical contact with a negative terminal block (92), the at least two cells (1) being connected in series between the two terminal blocks (92), positive and negative, of the accumulator block (9).

9. Accumulator block (9) according to claim 8, characterized in that, the cells (1) having substantially planar arrangements, these cells (1) are juxtaposed inside the casing (91) while being supported by their surfaces, so that, by compression, the folded contact tab (21) of the positive electrodes (2) of one cell (1) is in electrical contact with the folded contact tab (21) of the negative electrodes (2) of another juxtaposed cell (1).

10. Accumulator block (9) according to claim 9, characterized in that at least one connecting bar is positioned as an intermediate contactor at the electrical junction between the folded contact tab (21) of the positive electrodes (2) of one cell (1) and the folded contact tab (21) of the negative electrodes (2) of another cell (1) juxtaposed and connected in series with the first cell (1).

11. Accumulator block (9) according to one of claims 8 to 10, characterized in that, the cells (1) having substantially planar arrangements, these cells (1) grouped inside the casing (91) of the accumulator block (9) in juxtaposed assemblies (12), the cells (1) being supported by their respective conductive contact interfaces (52) inside each assembly (12) and connected in series, so that the contact tab (21) of the positive electrodes (2) of one cell (1) are in electrical contact with the contact tab (21) of the negative electrodes of another juxtaposed cell (1), at least one connecting bar being positioned as an intermediate contactor between two pairs of cells (1) respectively arranged in two juxtaposed assemblies (12).

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