- Terminal assembly structure for a battery cell forming a self-retaining terminal block and method for assembling such a terminal assembly structure

Abstract

The invention relates to a terminal assembly structure (10) for a battery cell (100), comprising a terminal (20) having a central body (21) radially delimited, with respect to a reference axis (A), by a peripheral portion (22) having a closed contour; a terminal support (30) forming a closed frame surrounding a central opening (31), the terminal support (30) comprising a shoulder portion (32) radially delimiting the central opening (31) and an upper portion (33) erected at least partially axially, the terminal support (30) delimiting an internal space (34) configured to receive the terminal (20) in an assembly position of the terminal assembly structure (10); an insulator (40) to ensure electrical insulation between the terminal (20) and the terminal support (30);in which the upper portion (33) of the terminal support (30) is deformed (330) to retain, with the shoulder portion (32), at least the terminal (20), the sealing ring (50) and the insulator (40). (Fig. 8);

Description

Title of the invention: Terminal assembly structure for a battery cell forming a self-retaining terminal block and method for assembling such a terminal assembly structure Technical field of the invention

[0001] The invention relates generally to the technical field of battery cells, in particular prismatic battery cells, and more specifically to the technical field of manufacturing battery accessories for new energy vehicles, and more particularly a power battery top cover structure.

[0002] The invention relates more specifically to a terminal assembly structure for a battery cell and a method for assembling such a terminal assembly structure. Prior art

[0003] Electric or hybrid traction or propulsion motor vehicles include one or more battery modules connected to an electrical network to power an electric motor (traction or propulsion).

[0004] The battery modules are grouped in a housing and together form a battery pack; this housing generally contains a mounting interface and connection terminals.

[0005] Each battery module is an assembly comprising several electrochemical cells generating current by chemical reaction, for example of the lithium-ion (or Li-ion) type, or of the Ni-Mh, Ni-Cd or lead type.

[0006] In certain configurations, it is possible to have no modules within the battery, a configuration commonly referred to as "cell-to-pack" (CTP). In fact, "cell-to-pack" designs integrate the battery cells directly into the battery pack, eliminating intermediate modules to improve energy density and simplify manufacturing.

[0007] An electrochemical cell includes, in particular, a stack of interconnected positive electrodes and a stack of interconnected negative electrodes. The individual positive and negative electrodes are placed alternately, each pair of positive and negative electrodes is separated by separator sheets, the whole forming a "stack". The positive electrodes are connected to each other at a positive terminal by means of positive tabs, and the negative electrodes are connected to each other at a negative terminal by means of negative tabs. More particularly, A terminal foot is associated with each polarity and the electrode tabs of the same polarity are usually soldered to a terminal foot of the corresponding terminal.

[0008] Each electrochemical stack is housed in a metal casing of the associated electrochemical cell. The casing is generally made of aluminum. Once the electrochemical stacks are integrated into a metal cup of the casing, a plate forming a lid for the electrochemical cell is laser-welded onto the cup to create the structural connection and seal the electrochemical cell, thus closing the casing.

[0009] It is common practice to assemble several electrochemical cells in series and / or parallel to produce battery modules, or battery packs in "cell-to-pack" designs, using an interconnecting device that ensures electrical contact between the terminals of two adjacent electrochemical cells. Lithium-ion (Li-ion) batteries are currently the most widely used in electric vehicles. A Li-ion battery is a collection of Li-ion accumulators, i.e., cells, connected in series or parallel in modules. The cells can be cylindrical, prismatic, or pouch-type.

[0010] The terminal is an integral part of a battery cell. The traditional terminal assembly method involves fitting the terminal into an assembly hole in the corresponding top cover of the casing, and then forming a relatively complex connection structure between the terminal and the top cover by welding, riveting, or injection molding in order to permanently connect the terminal to the top cover mechanically, but electrically. However, the process of forming a connection structure is relatively complicated, and the material properties of the top cover must be taken into account, which makes the design and manufacturing process of the battery top cover cumbersome, resulting in low efficiency and high production costs.

[0011] The terminals, with their positive and negative polarity, also form a particularly large and bulky electrical connection area. It is therefore always necessary to reduce the compactness of this area while optimizing its electrical performance, the objective being to improve volumetric efficiency.

[0012] The volumetric efficiency of a prismatic battery cell is the ratio between the volume of the electrode stack and the volume of the minimum box in which the cell can be completely enclosed. The higher the volumetric efficiency, the better the design.

[0013] However, the solutions known in the prior art often involve a large number of parts to fix a terminal to the cell housing and require assembly and manufacturing processes that are sometimes complex. Description of the invention

[0014] The present invention aims to remedy all or part of the drawbacks of the prior art by proposing in particular a terminal assembly structure in which the assembly procedure is simplified and the setup time reduced.

[0015] Another objective of the invention is to increase the volumetric efficiency of the battery cell.

[0016] According to a first aspect of the invention, a terminal assembly structure for a battery cell is provided, comprising at least: • a terminal having a central body radially delimited, with respect to a reference axis, by a peripheral portion having a closed contour; • a terminal support forming a closed frame surrounding a central opening, the terminal support comprising a shoulder portion radially delimiting the central opening and an upper portion erected at least partly axially, the terminal support delimiting an internal space configured to receive the terminal in an assembly position of the terminal assembly structure; • an insulator to ensure electrical insulation between the terminal and the terminal support; the upper portion of the terminal support is deformed to hold at least the terminal and the insulator securely, the shoulder portion contributing to this hold.

[0017] Thanks to this combination of features, a simple deformation step of the terminal support allows the terminal assembly structure to be assembled to form a self-retaining terminal block. The stacked elements, including at least the terminal and the insulator, are axially pressed into the internal space between two parts of the terminal support: the shoulder portion and the upper portion.

[0018] In one embodiment, the deformation of the upper portion of the terminal support is a mechanical deformation, preferably so as to axially bring an end portion of the upper portion closer to the shoulder portion.

[0019] In one embodiment, in the assembly position of the bollard assembly structure, at least a portion of the upper part of the bollard support and a portion of the peripheral part of the bollard have an axial overlap, with respect to the reference axis, preferably continuous along the closed contour. In fact, in such a combination of features, the bollard assembly structure is arranged such that, in the assembly position, a distal end portion of the upper portion, after deformation, defines an opening having a diameter strictly smaller than the external diameter of the circular closed contour of the peripheral part of the bollard. The bollard may have an external diameter The diameter of the terminal support is greater than the inner diameter after deformation, creating a metallic overlap between the terminal and the support on the upper face. Consequently, it reinforces the structure and adds rigidity to the upper portion.

[0020] In one embodiment, the terminal assembly structure includes a sealing ring radially surrounding the central opening of the terminal support and positioned between at least one shoulder portion of the terminal support and a portion of the peripheral portion of the terminal. The deformation of the upper portion of the terminal support maintains, along with the shoulder portion, the terminal, the insulator, and the sealing ring. In this configuration, the terminal assembly structure includes a sealing ring to ensure sealing and electrical insulation between the terminal and the terminal support.

[0021] In one embodiment, in the assembly position of the terminal assembly structure, the peripheral portion of the terminal is supported by the shoulder portion of the terminal support. It is understood that this support may be direct or indirect. For example, in the case where the sealing ring is placed between the peripheral portion of the terminal and the shoulder portion of the terminal support.

[0022] In one embodiment, the insulator radially surrounds the central body of the terminal and is designed to be placed against a part of the peripheral portion of the terminal on an external side, opposite the internal side oriented towards the shoulder portion, in the assembly position.

[0023] In one embodiment, the insulator has an edge portion, which is higher than the upper surface of the terminal at the stacking stage, the edge portion covering at least partially the deformation of the upper portion of the terminal support in the assembly position of the terminal assembly structure, the edge portion preferably having a donut shape, positioned axially at a lower level of the upper surface of the terminal and expanded concentrically with the terminal in the assembly position of the terminal assembly structure.

[0024] In one embodiment, the terminal and the terminal support are electrically conductive, preferably metallic.

[0025] In one embodiment, the upper portion of the terminal support is deformed by a mechanical press or an orbital riveting machine.

[0026] In one embodiment, the peripheral portion is formed by a portion projecting radially from the central body of the terminal.

[0027] In one embodiment, the terminal has an annular shape, the peripheral portion being annular.

[0028] In one embodiment, the terminal support device has an annular shape.

[0029] In one embodiment, the insulator has an annular shape.

[0030] In one embodiment, the sealing ring has an annular shape.

[0031] In one embodiment, the terminal assembly structure has an annular shape. In such a configuration, the terminal, the terminal support, the insulator and the sealing ring, if applicable, each have an annular shape.

[0032] In one embodiment, a lower part of the central body penetrates axially through the central opening, in the assembly position.

[0033] According to another aspect of the invention, a method for assembling a terminal assembly structure as described above for a battery cell is provided, comprising: • the stacking of at least the terminal, preferably the sealing ring, the insulator and the terminal support so that the terminal and the insulator are received in a stacked position, at least in part, in the internal space of said terminal support; • the deformation of the upper part of the terminal support to retain, with the shoulder portion, at least the terminal and the insulator, and preferably also the sealing ring, if applicable.

[0034] In one embodiment, the step of deforming the upper portion of the terminal support consists of mechanically deforming the upper portion of the terminal.

[0035] In one embodiment, during the deformation step, the upper portion is deformed by axially bringing an end portion of the upper portion of the shoulder part closer together.

[0036] In one embodiment, during the deformation step, the end portion of the upper portion is deformed so as to approach the main reference axis.

[0037] In one embodiment, during the deformation step, the end portion of the upper portion is deformed so as to axially cover, at least partially, the peripheral portion of the terminal.

[0038] In one embodiment, after the deformation step of the upper portion of the terminal support, the assembly method of the terminal assembly structure includes a welding step of the terminal assembly structure forming a self-retaining terminal block to a battery cell cover.

[0039] In one embodiment, the terminal assembly structure includes a sealing ring which is stacked with the terminal and the insulator during the stacking step, so that the terminal, the insulator and the sealing ring are received in a stacked position, at least in part, in the internal space of said terminal support.

[0040] In one embodiment, the insulator has an edge portion that is higher than the upper surface of the terminal at the stacking stage, the method comprising a step of at least partially covering the deformation of the upper portion of the terminal support by a deformation step, preferably with heat and mechanical force, to change the donut-shaped edge portion, positioned axially at a lower level of the upper surface of the terminal and expanded concentrically with the terminal in the assembly position of the terminal assembly structure.

[0041] In one embodiment, the deformation step of the upper portion of the terminal support is carried out by stamping or pressing. Brief description of the figures

[0042] Other advantages and features of the present invention will become apparent from the following description of a specific embodiment of the invention, with reference to the accompanying figures, which illustrate: • [Fig.1]: a schematic view of a battery cell according to a first embodiment; • [Fig.2]: an isometric cross-sectional and perspective view of a terminal assembly structure attached to a top cover of the battery cell according to the first embodiment; • [Fig.3]: an isometric and exploded perspective view of the terminal assembly structure according to the first embodiment; • [Fig.4]: a vertical cross-sectional view of [Fig.3]; • [Fig. 5]: an isometric perspective view of the terminal support according to the first embodiment; • [Fig.6]: a vertical cross-sectional view of [Fig.5]; • [Fig. 7]: an isometric perspective and cross-sectional view of the structure terminal assembly according to the first embodiment during the implementation of the assembly process of such a terminal assembly structure, in a stacked position; • [Fig.8]: a cross-sectional view of the assembly according to [Fig.7], during the assembly process, in the stacked position just before deformation by a press; • [Fig.9]: a view similar to [Fig.8], after deformation by the press; • [Fig. 10]: an isometric perspective and cross-sectional view of the structure terminal assembly according to the first embodiment, after deformation of the terminal support; • [Fig. 11]: a view of the terminal assembly structure according to the first embodiment and of a top cover, before welding; • [Fig. 12]: a view of the terminal assembly structure welded to the upper cover according to the first embodiment; • [Fig. 13]: a longitudinal vertical cross-sectional view of a top cover comprising two terminal assembly structures according to the first embodiment, the first of the two terminal assembly structures being associated with the positive polarity terminal, the other of the two terminal assembly structures being associated with the negative polarity terminal; • [Fig. 14]: a detailed view of [Fig. 13]; • [Fig. 15]: a detailed view of [Fig. 13]; • [Fig. 16]: an isometric cross-sectional and perspective view of a structure terminal assembly in a second embodiment; • [Fig. 17]: a vertical cross-sectional view of part of a battery cell, at the level of a terminal assembly structure attached to a top cover, according to the second embodiment; • [Fig. 18]: a cross-sectional view of the terminal assembly structure of [Fig.16], during the assembly process, in stacked position and just before the deformation of the upper edge of the insulator by a hot press; • [Fig. 19]: a view similar to [Fig. 18], after deformation of the insulation by a hot press; • [Fig.20]: a longitudinal vertical cross-sectional view of a top cover comprising two terminal assembly structures according to the second embodiment, the first of the two terminal assembly structures being associated with the positive polarity terminal, the other of the two terminal assembly structures being associated with the negative polarity terminal; • [Fig.21]: a detailed view of [Fig.20]; • [Fig.22]: a detailed view of [Fig.20]; • [Fig. 23]: A longitudinal vertical cross-sectional view of an upper lid comprising two terminal assembly structures according to a third embodiment, the first of the two terminal assembly structures being associated with the positive polarity terminal, the other of the two terminal assembly structures being associated with the negative polarity terminal; • [Fig.24]: a detailed view of [Fig.23]; • [Fig.25]: a detailed view of [Fig.23].

[0043] For clarity, the corresponding reference numbers refer to the same parts or corresponding parts in each of the figures.

[0044] In the description and claims, for the sake of clarity, the terms longitudinal, transverse and vertical are adopted with reference to the trihedron X, Y and Z represented in the figures. Detailed description of the implementation methods

[0045] A "battery" (not illustrated) is defined as a plurality of electrochemical cells 100 electrically connected to each other. According to a particular example of a battery, the plurality of electrochemical cells 100 is arranged in the form of one or more assemblies, each assembly comprising a plurality of electrochemical cells 100 electrically connected to each other and mechanically linked to each other by a junction system, such as junction plates (not illustrated).

[0046] An electrochemical cell 100 comprises, particularly in a prismatic cell, several layers of positive electrodes electrically connected in parallel and several layers of negative electrodes electrically connected in parallel, and separators to provide electrical isolation between each layer of positive electrode and the alternately placed negative electrode layer, known as a "stack" 140. These electrode stacks 140 are placed inside a housing or casing 130 to mechanically delimit the cell. The grouped positive electrodes connect to the positive terminal of an electrochemical cell, and the grouped negative electrodes connect to the negative terminal.In other words, a prismatic battery cell generally comprises at least one stack of 140 electrodes, two current collectors (positive and negative), and two grouped pluralities of flexible electrode leads 150 for the positive and negative electrodes that connect this stack of 140 positive electrodes (cathodes) to one (positive) of the current collectors and this stack of negative electrodes (anodes) to the other (negative) current collector.

[0047] Figures 1 to 15 illustrate the structure of a terminal assembly in a first embodiment.

[0048] As shown in [Fig. 1] and [Fig. 13], the electrochemical cell 100 has a prismatic shape and the corresponding housing 130 consists of a cup 120 closed by a lid 110.

[0049] The upper cover structure 110 of the battery described in this embodiment comprises the upper cover 110 and two terminal assembly structures (10, 10A, 10B) on the same upper cover 110 and are respectively equipped with a positive terminal assembly structure 10A and a negative terminal assembly structure 10B to form an upper cover structure integral with the cell.

[0050] The terminal assembly structure 10 (indifferently positive or negative in this figure) comprises a terminal 20 having a central body 21 radially delimited, with respect to a reference axis A, by a peripheral portion 22 having a closed contour, the terminal 20 being made of one or more conductive materials. The central body is generally disc-shaped. Such a peripheral portion 22 is formed by a portion projecting radially from the central body 21 of the terminal 20. As shown in [Fig.1], the group of tabs 150 of the same polarity in the stacks 140 is connected to the associated terminal 10. In this embodiment, the terminal 20 has an annular shape, the terminal 20 having a shape which is rotationally symmetric with respect to the reference axis A in the stacking and assembly positions.

[0051] The terminal assembly structure 10 also includes a terminal support 30 which forms a closed frame surrounding a central opening 31, the terminal support 30 including a shoulder portion 32 radially delimiting the central opening 31 and an upper portion 33 erected at least partly axially, the terminal support 30 delimiting an internal space 34 designed to receive the terminal 20 in an assembly position of the terminal assembly structure 10.

[0052] The terminal support 30 also includes a retaining collar 35 from which the shoulder portion 32 and the upper portion 33 extend. This retaining collar 35 externally delimits the closed annular outer contour, the radial dimension of which is configured to fit an internal diameter of a corresponding hole 111 in the upper cover 110 so as to be fixed together in a fixing position in which the terminal assembly structure 10 closes said hole 111. The retaining collar 35 radially surrounds the shoulder 32 and the upper portion 33.

[0053] The terminal support 30 is made of metal, for example aluminum or stainless steel, and is formed from a single piece. A metal preferably compatible with laser welding and inert to the electrochemical reactions inside the cell 100 should be chosen. In other words, the retaining collar 35, the shoulder 32, and the upper portion 33 are formed from a single piece. In this embodiment, the terminal support 30 has an annular shape, the terminal 20 having a shape that is rotationally symmetrical about the reference axis A in the stacking and assembly positions.

[0054] The peripheral portion 22 of the terminal 20 has a closed circular contour with an external diameter strictly larger than the internal diameter of the central opening 31 of the terminal support 30. In this way, when the terminal 20 enters axially into the internal space 34 of the terminal support 30, the terminal 20 is held on an internal side 22B by the shoulder portion 32 of the terminal support 30. In the stacked and assembled positions, the terminal 20 and the terminal support 30 are positioned coaxially with respect to each other. In such a configuration, in the assembly position of the terminal assembly structure 10, the peripheral portion 22 of the terminal 20 bears against the shoulder portion 32 of the terminal support 30.

[0055] The terminal assembly structure 10 also includes an insulator 40 to ensure electrical insulation between the terminal 20 and the terminal support 30, given The terminal support 30 and terminal 20 are electrically conductive. The insulator 40 has an annular shape, which is rotationally symmetrical about the reference axis A in the stacking and assembly positions. The insulator material is preferably an engineering plastic such as PPS, PA+GF, etc. This material must be highly non-conductive and heat-resistant so that laser beam welding can be applied to the terminals and the retaining collar.

[0056] The terminal assembly structure 10 comprises a sealing ring 50 radially surrounding the central opening 31 of the terminal support 30. The sealing ring 50 has an annular shape, which is rotationally symmetrical about the reference axis A in the stacking and assembly positions. The sealing ring 50 is positioned, more particularly interposed, on an axial and radial portion between the shoulder portion 32 of the terminal support 30 and the peripheral portion 22 of the terminal 20. The material of the sealing ring is preferably a technical rubber such as FKM elastomer, PFA elastomer, etc. This material must be highly elastic under long-term compression, heat-resistant, chemical-resistant, and very durable.

[0057] The terminal assembly structure 10 is composed of a very limited number of parts, namely four parts which are the terminal 20, the terminal support 30, the insulator 40, and the sealing ring 50. The terminal assembly structure 10 therefore has a relatively simple design.

[0058] According to the invention, a deformation 330 of the upper portion 33 of the terminal support 30 is made to securely hold / support the terminal 20, the insulator 40 and the sealing ring 50, the shoulder portion 32 participating in this holding.

[0059] Thanks to this configuration, the assembly process of such a terminal assembly structure 10 is also simplified, as will be explained in more detail in the following description.

[0060] The method of assembling the terminal assembly structure 10 includes a step of stacking the terminal support 30, the sealing ring 50, the terminal 20 and the insulator 40 so that the sealing ring 50, the terminal 20 and the insulator 40 are each received in a stacked position, at least in part, in the internal space 34 of said terminal support 30.

[0061] During the stacking step, the upper portion 33 of the terminal support 30 generally extends vertically so as to present a generally cylindrical shape, a distal end portion of the upper portion 33 defining an opening 33' through which the parts, i.e. the sealing ring 50, the terminal 20 and the insulator 40, are inserted to be placed in the internal space 34 of the terminal support 30.

[0062] The stacking step includes a first sub-step of positioning the sealing ring 50 in the internal space 34 of said terminal support 30.

[0063] The sealing ring 50 comprises a cylindrical annular portion 51 whose axis corresponds to the reference axis A in the stacking and assembly positions and whose outer diameter is substantially equal to the inner diameter of the central opening 31. The sealing ring 50 also comprises a horizontal annular portion 52 extending from the cylindrical portion 51 and bearing against a horizontal surface of the shoulder portion 32 facing the inner space 34, knowing that an outer diameter of the horizontal portion 52 is strictly greater than the inner diameter of the central opening 31.In such a configuration, in the stacked position (but also in the assembly position obtained after deformation), the sealing ring 50 and the terminal support 30 are positioned coaxially with respect to each other so that the sealing ring 50 is directly supported by the shoulder portion 32 both axially by means of the horizontal portion 52 and radially by means of the axial or vertical cylindrical portion 51 of the sealing ring 50.

[0064] The stacking step then includes a second sub-step consisting of positioning the terminal 20 in the internal space 34 of the terminal support 30.

[0065] As previously specified, the peripheral portion 22 of the terminal 20 has a closed circular contour with an external diameter strictly greater than an internal diameter of the central opening 31 of the terminal support 30. In this way, when the terminal 20 enters axially into the internal space 34 of the terminal support 30, the terminal 20 is held on an internal side 22B by the shoulder portion 32 of the terminal support 30. Due to the presence of the sealing ring 50, the peripheral portion 22 of the terminal 20 comes into contact with and is directly supported by the sealing ring 50, in particular axially against the horizontal part 52 of the sealing ring 50.In such a stacked position, the terminal 20, the sealing ring 50 and the terminal support 30 are positioned coaxially with respect to each other and the peripheral portion 22 of the terminal 20 is indirectly supported by the shoulder portion 32 of the terminal support 30 since the sealing ring 50 is interposed between said terminal 20 and the terminal support 30.

[0066] The terminal 20 comprises a lower portion 211 that extends axially to a vertically lower level than the peripheral portion 22. This lower portion 211 has a cylindrical shape and extends axially so as to penetrate through the central opening 31 in the stacked and assembled position. The outer diameter of this lower portion 211 is less than or equal to the inner diameter of the cylindrical portion 51 of the sealing ring 50. Due to the presence of the sealing ring 50, the lower portion 211 of the terminal 20 is separated from a distal end of the shoulder portion 32 by the cylindrical portion 51 of the sealing ring 50.

[0067] The stacking step then includes a third sub-step consisting of positioning the insulator 40 in the internal space 34 of the terminal support 30.

[0068] The insulator 40 radially surrounding the central body 21 of the terminal 20 is arranged to be placed against an annular part of the peripheral portion 22 of the terminal 20, on an external side 22A, opposite the internal side 22B oriented towards the shoulder portion 32, in the stacked and assembled positions.

[0069] The insulator 40 therefore has a tubular shape which extends axially between: • a lower end 40B having an internal diameter greater than or equal to an external diameter of the peripheral portion 22 and an external diameter less than or equal to an internal diameter of the terminal support 30 taken locally axially at the level of the retaining collar 35 or at a proximal end of the upper portion 33; and • an upper end 40A.

[0070] During the stacking operation, the insulator 40 is placed in the internal space 34 of the terminal support and rests against the shoulder portion 32, which axially holds it, just as it axially holds the sealing ring 50 and the terminal 20. In this stacked position, the insulator 40 is positioned so as to radially surround the terminal 20, which is itself radially surrounded by the upper portion 33 of the terminal support 30. In this way, the insulator 40 is positioned between the terminal 20 and the terminal support 30, in particular the upper portion (33 of the terminal support 30) over an axial portion extending at least from a lower axial end of the peripheral portion 22 to an upper axial end of the terminal 20. The insulator thus provides insulation between the terminal 20 and the terminal support. 30.

[0071] Once the stacking step has been carried out, the assembly illustrated in [Fig.7] is obtained. The stacking step is then followed by a deformation step of the upper portion 33 of the terminal support 30 to retain, with the shoulder portion 32, the terminal 20, the insulator 40 and, where applicable as is the case in this embodiment, the sealing ring 50.

[0072] After the deformation step of the upper portion 33 of the terminal support 30, the assembly process of the terminal assembly structure 10 includes a welding step of the terminal assembly structure 10 forming a self-retaining terminal block to the cover 110 of the battery cell 100.

[0073] The deformation step is carried out by a deformation tool 200, for example a press. The terminal assembly structure 10 is positioned on a base or support matrix 201 of the deformation tool 200 and a movable element 202 the deformation tool 200 forming a punch is arranged to press the terminal assembly structure 10.

[0074] During its descent, the upper portion 33 of the terminal support 30 comes to rest against a deformation guide ramp 203 of the punch 202 of the deformation tool 200 and guides the deformation 330 during the descent of the punch 202 in the direction of a reduction of the distance between the punch 202 and the support die 201 of the deformation tool 200.

[0075] During this operation, the upper portion 33 of the terminal support is deformed so as to approach axially the shoulder portion 32, so that the upper portion 33 and the shoulder portion 32 pinch or sandwich the superimposed assembly of the sealing ring 50, the terminal 20, in particular the peripheral portion 22 of the terminal 20, and the insulator 50.

[0076] In other words, during the deformation step, the upper portion 33 is deformed by bringing one end of the upper portion 33 axially closer to the shoulder portion and radially closer to the main reference axis A.

[0077] It follows that a distal end of the upper portion 33 delimits, after deformation, an opening 33' having a diameter strictly less than the external diameter of the closed circular contour of the peripheral portion 22 of the terminal 20.

[0078] To ensure this axial support in the assembly position of the terminal assembly structure 10, after the deformation of the upper portion 33, there is an axial overlap between the upper portion 33 of the terminal support 30 and the peripheral portion 22 of the terminal 20, this overlap being annular and continuous on this annular perimeter.

[0079] A self-retaining terminal block is then obtained, arranged to be fixed in the cover 110. Thus, during such an assembly step, the upper portion 33 is deformed 330 to retain, with the shoulder portion 32, the sealing ring 50, the terminal 20 and the insulator 40, respectively in the axial direction from the shoulder portion 32 to the upper portion 33.

[0080] Once the terminal assembly structure 10 is obtained, thus forming a self-retaining terminal block delimited on its annular periphery by the retaining collar 35 of the terminal support 30, the assembly process includes a step of fixing said terminal assembly structure 10 onto the cover 110 of the battery cell 100.

[0081] As described previously, the retaining collar 35 externally delimits a closed annular outer contour whose radial dimension is designed to be fitted to an internal diameter of a corresponding hole 111 of the upper cover 110 in order to be fixed together in a fixing position in which the terminal assembly structure closes said hole 111.

[0082] In this embodiment, the fixing step is a welding step of the terminal assembly structure 10 to the cover 110 of the battery cell 100, i.e. the peripheral outer edge of the retaining collar 35 is welded to the inner edge of the hole 111 of the cover 110 of the battery cell 100.

[0083] Thus, during the fixing step: • the terminal assembly structure 10 forming a self-retaining terminal block is inserted into the hole 111 of the cover 110; • Laser beam welding is applied over the entire perimeter of the interface of the two parts which are the terminal support 30 of the terminal assembly structure 10 and the cover 110 of the battery cell 100.

[0084] It is understood that certain design differences may facilitate the process and / or the cost depending on the product according to the invention.

[0085] The terminal assembly structure 10 has a shape that is rotationally symmetric with respect to the reference axis A in the stacked and assembled positions, so that the angular position of the terminal assembly structure during the fixing step is not a constraint.

[0086] In the assembly position of the structured terminal 10, a disc-shaped terminal 20 is obtained, the axial or vertical thickness of which substantially delimits the thickness of the structured terminal 10, and extends between a lower contact face open towards the inside of the cell 100 and an upper face open towards the outside and allowing the cell to be connected to the associated electrical circuit.

[0087] The disc-shaped terminal 20 is radially surrounded by the terminal support 30, which holds it firmly in the axially tight annular space between the shoulder portion 32 and the upper portion 33 of the terminal support 30. The insulator 40 and the ring 50 provide electrical insulation between the terminal 20 and the terminal support 30 and also prevent any play between the parts.

[0088] Thanks to the invention, it is therefore possible to obtain a terminal assembly structure 10 in the form of a self-retaining terminal block, for which the assembly method or process is simpler and faster. It is also possible to obtain a thinner terminal assembly structure 10, so that the volumetric efficiency of the associated prismatic battery cell can be improved.

[0089] Figures 16 to 22 illustrate the structure of a terminal assembly in a second embodiment. This embodiment differs essentially from the first embodiment in that the insulator 40 includes an edge portion 401 which is an extension of the upper end 40A of the insulator 40. In the stacked position, the edge portion 401 protrudes axially from the internal space 34. In the stacked and non-assembled position, the edge portion 401 is higher than the upper surface of the terminal 20.

[0090] Once the deformation step has been carried out by a deformation tool 200, the edge portion 401 extends annularly and continuously as an axial projection with respect to the upper portion 33 deformed, and also with respect to the terminal 20.

[0091] The deformation step is then followed by a forming step carried out by a forming tool 200' consisting in this embodiment of a heat gun, arranged to form the edge portion 401, and more particularly in this embodiment, to flatten the edge portion 401 on the outer surface of the upper portion 33. The heat gun 200' heats the edge portion 401 of the insulator 40 and softens the area where the heat is transferred and produces a plastic deformation depending on the shape of the surface heated by the heat gun, as well as the shape of the outer surface of the upper portion 33.During this deformation step of the edge portion 401 of the insulator 40, the deformation 330 of the upper portion 33 of the terminal support 30 is covered at least partially by the edge portion 401 of the insulator 40, preferably under the effect of heat and a mechanical force, to give the edge portion 401 of the insulator 40 a ring shape, positioned axially at a lower level of the upper surface of the terminal 20 and extended concentrically with the terminal 20 in the assembly position of the terminal assembly structure.

[0092] With such a forming step in the assembly process, the edge portion 401 of the insulator 40 stretches and covers the terminal support 30 more widely and, consequently, improves the electrical separation distance and the leakage distance between the terminal 20 and the terminal support 30, which must be strictly electrically insulated.

[0093] In another embodiment, it is possible to perform the deformation and forming steps simultaneously. It is also possible that the deformation tool 200 and the forming tool 200' are the same tool.

[0094] Figures 23 to 25 illustrate the structure of a terminal assembly according to a third embodiment. This embodiment differs essentially from the second embodiment in that the terminal support is obtained from an annular plate. The upper portion 33 and the shoulder portion 32 are separated by the retaining collar 35, which is formed from a fold in the annular plate.

[0095] The advantage of such a configuration is that it is simple and easy to obtain, the terminal support being particularly simple to manufacture and inexpensive.

[0096] Of course, the present invention, as described, is given by way of example. It is understood that persons competent in the field may be able to carry out different variations of the invention without departing from the scope of the invention.

[0097] For example, in these embodiments, the deformation step is carried out by pressure, but it can also be carried out by stamping / drawing, riveting or orbital riveting.

[0098] It is emphasized that all features, as they are apparent to a person skilled in the art from the present description, drawings and attached claims, even if in practice they have only been described in relation to other specific features, both individually and in any combinations, can be combined with other features or groups of features disclosed herein, provided that this has not been expressly excluded or that technical circumstances make such combinations impossible or meaningless.

Claims

Demands

1. Terminal assembly structure (10) for a battery cell (100), comprising at least: - a terminal (20) having a central body (21) radially delimited, with respect to a reference axis (A), by a peripheral portion (22) having a closed contour; - a terminal support (30) forming a closed frame surrounding a central opening (31), the terminal support (30) comprising a shoulder portion (32) radially delimiting the central opening (31) and an upper portion (33) erected at least partially axially, the terminal support (30) delimiting an internal space (34) configured to receive the terminal (20) in an assembly position of the terminal assembly structure (10); - an insulator (40) to ensure electrical insulation between the terminal (20) and the terminal support (30);in which the upper portion (33) of the terminal support (30) is deformed (330) to hold at least the terminal (20) and the insulator (40) securely, the shoulder portion (32) participating in this holding.;

2. Terminal assembly structure (10) according to claim 1, wherein, in the assembly position of the terminal assembly structure (10), at least a portion of the upper portion (33, 330) of the terminal support (30) and a portion of the peripheral portion (22) of the terminal (20) have an axial overlap, with respect to the reference axis (A), preferably continuous along the closed contour.

3. Terminal assembly structure (10) according to claim 1 or 2, wherein it comprises a sealing ring (50) radially surrounding the central opening (31) of the terminal support (30) and placed between, at least a part of the shoulder portion (32) of the terminal support (30) and a part of the peripheral portion (22) of the terminal (20), the deformation (330) of the upper portion (33) of the terminal support (30) now, with the shoulder portion (32), the terminal (20), the insulator (40) and the sealing ring (50).

4. Terminal assembly structure (10) according to any one of claims 1 to 3, wherein, in the assembly position of the terminal assembly structure (10), the peripheral portion (22) of the terminal (20) is supported by the shoulder portion (32) of the terminal support (30).

5. Terminal assembly structure (10) according to any one of the preceding claims, wherein the insulator (40) radially surrounds the central body (21) of the terminal (20) and is arranged to be placed against a part of the peripheral portion (22) of the terminal (20) on an external side (22A), opposite the internal side (22B) oriented towards the shoulder portion (32), in the assembly position.

6. Terminal assembly structure (10) according to any one of the preceding claims, wherein the terminal (20) and the terminal support (30) are electrically conductive, preferably metallic.

7. Terminal assembly structure (10) according to any one of the preceding claims, wherein the upper portion (33) of the terminal support (30) is deformed by a mechanical press or an orbital riveting machine.

8. Terminal assembly structure (10) according to any one of the preceding claims, wherein the peripheral portion (22) is formed by a portion projecting radially from the central body (21) of the terminal (20).

9. Terminal assembly structure (10) according to any one of the preceding claims, wherein the terminal (20) has an annular shape, the peripheral portion (22) being annular, and the terminal assembly structure (10) has an annular shape.

10. Terminal assembly structure (10) according to any one of the preceding claims, wherein a lower part (211) of the central body (21) penetrates axially through the central opening (31), in the assembly position.

11. Method of assembling a terminal assembly structure (10) according to any one of the preceding claims for a battery cell (100), comprising: - stacking at least the terminal (20), the insulator (40) and the terminal support (30) so that the terminal (20) and the insulator (40) are received in a stacked position, at least in part, in the internal space (34) of said terminal support (30); - the deformation of the upper portion (33) of the terminal support (30) to retain, with the shoulder portion (32), at least the terminal (20) and the insulator (40).

12. Method of assembling a terminal assembly structure (10) according to the preceding claim, wherein after the step of deforming the upper portion of the terminal support (30), it includes a step of welding the terminal assembly structure (10) forming a self-retaining terminal block to the cover plate (110) of the battery cell (100).

13. Method of assembling a terminal assembly structure (10) according to claim 11 or 12, wherein the terminal assembly structure (10) comprises a sealing ring (50) which is stacked with the terminal (20) and the insulator (40) during the stacking step, such that the terminal (20), the insulator (40) and the sealing ring (50) are received in a stacked position, at least in part, in the internal space (34) of said terminal support (30).

14. A method for assembling a terminal assembly structure (10) according to any one of claims 11 to 13, wherein the insulator (40) has an edge portion (401), which is higher than an upper surface of the terminal (20) at the stacking stage, the method comprising a step of at least partially covering the deformation (330) of the upper portion (33) of the terminal support (30) by a deformation step, preferably using heat and mechanical force, in order to transform the edge portion (401) into a donut shape, positioned axially at a lower level of the upper surface of the terminal (20) and expanded concentrically with the terminal (20) in the assembly position of the terminal assembly structure.

15. Method of assembling a terminal assembly structure (10) according to any one of claims 11 to 14, wherein the deformation step of the upper portion (33) of the terminal support (30) is carried out by stamping or pressing.

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