Compression tool for compressing a product according to a predetermined force and associated compression process

Abstract

The invention relates to a compression tool (100) for compressing a product (1), such as a stack of electrodes or an electric battery cell, the compression tool (100) being characterized in that it comprises at least: a working support (10) having a working surface (11) configured to support the product (1) to be compressed; an armature (20) comprising a movable structure (21) and means for moving the movable structure (21) relative to the working support (10); a pressing plate (30) configured to come into contact and bear against the product (1) to be compressed in a working position in which the product (1) is compressed between the working support (10) and the pressing plate (30);the pressing plate (30) being connected to the mobile structure (21) of the reinforcement (20) by means of connection (25) comprising means of energy storage (26) disposed between the mobile structure (21) and the pressing plate (30) so as to prestress the pressing plate (30) with respect to the mobile structure (21) of the reinforcement (20), and at least one means of adjusting the prestress. (Fig. 2);

Description

Title of the invention: Compression tool for compressing a product according to a predetermined force and associated compression method. Technical field of the invention

[0001] The invention relates, in general, to the technical field of tools enabling the compression of a set of parts, in particular components of an electric battery cell.

[0002] The invention relates more specifically to a compression tool for compressing a product according to a predetermined force, such as an electrode stack or an electric battery cell, and an associated compression method. Prior art

[0003] Motor vehicles with electric or hybrid traction or propulsion include one or more battery modules connected to a power network to supply an electric motor (traction or propulsion).

[0004] The battery modules are grouped in a casing and together form a battery block, also often referred to by the English expression "battery pack", this casing generally containing a mounting interface and connection terminals.

[0005] Each battery module comprises at least one electrochemical cell generating current by chemical reaction. An electrochemical cell comprises, in particular, a stack of interconnected positive electrodes and a stack of interconnected negative electrodes, separated by a separator, known as a "stack". The interconnected positive electrodes form a positive terminal, and the interconnected negative electrodes form a negative terminal.

[0006] It is known to assemble, in series and / or in parallel, a plurality of electrochemical cells in order to produce battery modules using an interconnection device ensuring electrical contact between the terminals of two neighboring electrochemical cells.

[0007] Each electrochemical cell comprises a cup within a metallic housing. The housing is metallic, generally made of aluminum. Once the electrode stacks are integrated into the cup, a lid-forming plate is laser-welded to the cup to create the structural connection and seal the electrochemical cell, thus closing the housing.

[0008] Battery cells are arranged in modules to obtain functional units. Grouping the cells into modules thus allows to manipulate sets of several cells, themselves forming sub-assemblies of the battery block or battery pack. Such a modular arrangement is implemented for various reasons. Indeed, such a design offers advantages, particularly in terms of modularity, maintenance, ease of manufacturing, standardization, and cost reduction.

[0009] Indeed, in the event of a cell or module failure, for example, it is simpler and more economical to replace only the defective module rather than the entire battery pack. Furthermore, manufacturing modules, which are smaller and more standardized than a battery pack, is easier and less expensive than manufacturing a single large battery pack. This also allows for more automated and efficient production.

[0010] At different stages of manufacturing electrochemical cells, or more generally electric batteries, a compression operation may be necessary in the process.

[0011] Each electrochemical cell generates current by chemical reaction, for example, lithium-ion (or Li-ion), Ni-Mh, Ni-Cd, or lead-acid. In the case of a liquid electrolyte electrochemical cell, a compression step is generally implemented to form the electrode stacks. Compressing the stack promotes intimate surface contact between the layers—successively the anode electrode, the separator film, and the cathode electrode—and also controls its thickness. This stack compression can, for example, be achieved by continuous rolling or by a press, such as a hydraulic or mechanical press.

[0012] Such a compression step is all the more important in the case of pouch-type cells, whose cell thickness is directly determined by the thickness of the electrode stack. The compression step thus allows for better control of the resulting cell thickness.

[0013] Similarly, for other types of electrochemical cells, particularly those with solid electrolyte, an electrode compression step is generally implemented at a predetermined pressure to ensure, in addition to a controlled thickness of the electrode stacks, good electrical contacts between the components.

[0014] Among the press tools used to implement compression steps, US patent no. 2022 / 00094009 is known, for example. This patent discloses a device comprising two external plates and two internal plates with openings for applying pressure to the battery. This device can be adjusted to apply different levels of pressure to the battery by means of screws. The objective of this invention is to improve the application of pressure to electrochemical cells and to enhance their durability and reliability.

[0015] US Patent No. 2022 / 029398 A1 is also known, which discloses an apparatus for manufacturing a battery element, the apparatus comprising a support for transporting a battery element to a worktable, in which the support comprises a first plate pressing a surface of the battery element; a second plate pressing the other surface of the battery element opposite the first surface; a clamping element pressing the first plate and the second plate in a direction in which the first plate and the second plate face each other; and a position alignment piece disposed in at least one of the first plate and the second plate and aligning a position of at least one of the first plate and the second plate with respect to the worktable.

[0016] However, one of the major problems with prior art compression devices is that manufacturing tolerances for the cells mean that each cell experiences a pressure difference that can affect the results obtained from the cells. For example, the pressure can be changed simply by altering the spring stiffness.

[0017] In addition, since the applied pressure depends on the torque, it cannot be reliably repeated over time, because the coefficients of friction change and have a major impact on the resulting screw tension.

[0018] Moreover, this type of mechanism cannot adapt to the different stacking thicknesses of electrodes or, more generally, of electrochemical cells.

[0019] Finally, applying pressure using fasteners screwed around the perimeter makes applying uniform pressure cumbersome. Indeed, it would be necessary to be able to screw and unscrew all the screws simultaneously, as the pressure would be applied with a potentially very significant gradient, which would be detrimental to such products. Description of the invention

[0020] The invention aims to remedy all or part of the disadvantages of the prior art by proposing in particular a solution enabling the repeatability of the application of a given pressure.

[0021] Another problem addressed by the invention is to ensure a uniform distribution of pressure, but also to be able to adapt to dimensional variability (production and assembly tolerances), in particular in terms of the thickness of the product to be compressed.

[0022] To this end, according to a first aspect of the invention, a compression tool is proposed for compressing a product, such as a stack of electrodes or an electric battery cell, the compression tool being characterized in that it comprises at least: - a work support with a work surface configured to support the product to be compressed; - an armature comprising a mobile structure and means of moving the mobile structure relative to the work support; - a pressing plate configured to come into contact and support the product to be compressed in a working position in which the product is compressed between the working support and the pressing plate; the pressing plate being connected to the mobile structure of the reinforcement by means of connection comprising means of energy storage disposed between the mobile structure and the pressing plate so as to prestress the pressing plate with respect to the mobile structure of the reinforcement, and at least one means of adjusting the prestress.

[0023] Thanks to such a combination of characteristics, it is possible to achieve a two-stage compression, on the one hand by applying a predetermined prestress to the pressing plate which, when it is in contact with the product, the said prestress can be released to apply the stress directly on the product, this with a well-controlled force.

[0024] According to one embodiment, the pressing plate has a pressing surface configured to come into contact and support against the product to be compressed in the working position, the pressing surface being parallel with respect to the working surface of the working support, independently of the position of the pressing plate with respect to the frame and independently of the position of the mobile structure with respect to the working support.

[0025] According to one embodiment, the mobile structure is mobile relative to the work support along one degree of freedom, preferably a single one, corresponding to an axial translation along a vertical reference axis, orthogonal to the work surface, of the mobile structure relative to the work support.

[0026] According to one embodiment, the pressing plate is movable relative to the moving structure along one degree of freedom, preferably a single one, corresponding to an axial translation along the vertical reference axis of the pressing plate relative to the moving structure.

[0027] According to one embodiment, the prestress adjustment means includes a means for adjusting the spacing distance between the pressing plate and the moving structure. This is a simple and precise way of applying the prestress.

[0028] According to one embodiment, the preload adjustment means comprises a threaded rod connected to the pressing plate and the moving structure, preferably fixedly attached to the pressing plate and passing through a hole in the moving structure, the adjustment means comprising a nut cooperating with the threaded rod on one side exterior of the mobile structure, opposite the interior side oriented towards the side of the pressing plate.

[0029] According to one embodiment, the connecting means comprise at least one guide rod separate from the adjusting means, preferably separate from the threaded rod, to guide in translation the movement of the pressing plate relative to the moving structure.

[0030] According to one embodiment, the frame is integral with the work support, the frame comprising a fixed structure fixedly integral with the work support, the mobile structure being mobile relative to the fixed structure.

[0031] According to one embodiment, the means of movement include a sliding link between the mobile structure and the fixed structure and means of locking the mobile structure relative to the fixed structure configured to immobilize the mobile structure relative to the fixed structure.

[0032] According to one embodiment, the energy storage means comprise at least one, preferably a plurality of, spring(s), preferably helical springs.

[0033] According to one embodiment, each guide rod is surrounded by an associated helical spring arranged coaxially, the helical spring being arranged between, preferably interposed between, the pressing plate and the moving structure.

[0034] According to one embodiment, the compression tool comprises at least one adjusting shim configured to be positioned between the moving structure and the pressing plate. The adjusting shim has a predetermined thickness, depending on the energy storage means, so as to be interposed between the moving structure and the pressing plate in a predetermined preload position where the energy storage means are constrained according to a predetermined force. Such an adjusting shim facilitates the repeatability of the adjustment operations for compression, with controlled consistency and optimal ease of adjustment. In particular, it may be necessary to ensure that the adjusting shim is made of a resistant material to limit its wear and guarantee the accuracy of the compression operations performed.

[0035] According to another aspect of the invention, it relates to a method of compressing a product, such as a stack of electrodes or an electric battery cell, by a compression tool as described above, notable in that the compression method comprises at least: - a step of adjusting the pressing plate relative to the mobile structure of the reinforcement so as to position the pressing plate in a predetermined prestressing position where the energy storage means are constrained according to a predetermined force; - a step involving moving the mobile structure relative to the working support so that the pressing plate comes into contact with the product to be compressed; and - a predetermined preload release step controlled by the adjustment means.

[0036] According to one embodiment, the step of adjusting the pressing plate relative to the moving structure of the frame includes - a step of positioning an adjustment shim between the moving structure and the pressing plate, the adjustment shim having a predetermined thickness depending on the energy storage means; and - a step of moving the pressing plate towards the moving structure until the predetermined prestressing position where the distance between the moving structure and the pressing plate corresponds to the thickness of the adjustment shim.

[0037] The positioning of the adjustment wedge can be controlled, for example, by a robotic arm. Brief description of the figures

[0038] Other features and advantages of the invention will become apparent from the following description, with reference to the accompanying figures, which illustrate: • [Fig.1]: a schematic side view of a compression tool, according to one embodiment of the invention; • [Fig.2]: a view of the compression tool of [Fig.1], during a step of adjusting a pressing plate relative to a moving structure of a reinforcement, the compression tool being shown in a predetermined prestressing position; • [Fig.3]: a view of the compression tool of [Fig.1], during a step of moving the mobile structure relative to a working support, the pressing plate being in contact against the product to be compressed; • [Fig.4]: a view of the compression tool of [Fig.1], once the step of moving the mobile structure relative to a working support has been completed, during the locking of the desired position of the mobile structure by locking means, to immobilize the mobile structure relative to the working support; • [Fig.5]: a view of the compression tool of [Fig.1], during a pre-stress release step predetermined by means of a control of the adjustment means.

[0039] For clarity, identical or similar elements are identified by identical reference signs throughout the figures. Detailed description of an implementation method

[0040] Figures 1 to 5 each illustrate a compression tool 100 for compressing a product 1, the tool being shown in different successive positions of the same compression process of the associated product 1.

[0041] The tool 100 comprises a work support 10 having a working surface 11 configured to support the product 1 to be compressed. The work support 10 is schematically represented here as a plate of constant thickness, comprising a lower surface resting on a suitable tool support. It is understood that the work support 10 can have variable shapes depending on its use. The horizontal working surface 11 supports the product 1 to be compressed locally at the level of a predetermined working zone located vertically below a pressing plate 30.

[0042] The pressing plate 30 is configured to come into contact and support against the product 1 to be compressed in a working position in which the product 1 is compressed between the working support 10 and the pressing plate 30.

[0043] The pressing plate 30 has a pressing surface 31 configured to come into contact and bear against the product 1 to be compressed in the working position and extending in a plane parallel to a horizontal reference plane and parallel to the working surface 11 of the working support 10. The working surfaces 11 and pressing surfaces 31 thus come together to clamp and compress the product 1 during a compression operation, like jaws.

[0044] In this embodiment, the work support 10 is fixed relative to a frame while the pressing plate 30 is mobile, in particular mobile in vertical translation, relative to the work support 10.

[0045] Regardless of its degree of mobility, in this embodiment the pressing surface 30 is kept parallel to the working surface 11 of the working support 10, therefore independently of its position during the process.

[0046] The compression tool 100 also includes a frame 20 comprising a fixed structure 22, a movable structure 21, and means 23 for moving the movable structure 21 relative to the working support 10. The frame 20 is fixed to the working support 10 via the fixed structure 22, which is fixedly attached to the working support 10. The movable structure 21 is connected to the fixed structure 22 by the means 23, such that the movable structure 21 is movable relative to the fixed structure 22. The frame 20 thus provides the connection between the working support 10 and the pressing plate 30.

[0047] The mobile structure 21 has the form of a rectangular parallelepiped-shaped plate having a plurality of orifices (not visible in the figures), preferably at least two, preferably at least three, here four, each traversed by a guide column extending vertically, parallel to a vertical reference axis Z. The holes are through-holes and pass vertically through the thickness of the plate of the moving structure 21. Each guide column has a cross-section configured to cooperate with one of the corresponding holes in the moving structure. In this way, the plate of the moving structure 21, extending parallel to a horizontal reference plane orthogonal to the vertical axis Z, is guided vertically in translation. The interaction between a guide column and an associated through-hole locally forms a sliding or pivot joint and together constitutes a means of guiding the moving structure 21 in vertical translation relative to the guide columns of the fixed structure 22, and more generally relative to the working support 10.Thus, the means of movement 23 include a sliding connection between the mobile structure 21 and the fixed structure 22 obtained by the plurality of guide columns cooperating through holes of complementary shape in the mobile structure 21.

[0048] The mobile structure 21 is thus mobile relative to the work support 10 along a single degree of freedom, corresponding to an axial translation along the vertical reference axis Z, orthogonal to the work surface 11, of the mobile structure 21 relative to the work support 10

[0049] The movement means 23 also include locking means 24 of the mobile structure 21 relative to the fixed structure 22, configured to immobilize the mobile structure 21 relative to the fixed structure 22 in a given vertical position. Thus, it is possible to vary the vertical height of the mobile structure 21 and to block or lock a position at a predetermined height using the locking means 24.

[0050] The locking means 24 comprise a clamping screw associated with each guide column. In particular, the rectangular parallelepiped plate of the movable structure 21 has a thickness greater than or equal to the outside diameter or nominal diameter of the associated screws. For each vertical hole receiving a guide column 221, a tapped hole extends horizontally and through between an edge of the plate of the movable structure 21 and the vertical hole receiving one of the associated guide columns. In this way, it is possible to tighten the screw, which comes into contact and bears transversely against the associated guide column 221 of the fixed structure 22, on the portion of the guide column 221 housed in the vertical hole of the movable structure 21.

[0051] The locking means 24 are integral with the mobile structure 21 and allow each of the connections between the mobile structure 21 and the fixed structure 22 to be locked. In this embodiment, the locking means 24 are specific to each guide column 221. Of course, these locking means 24 can be configured to be controlled in a synchronized manner.

[0052] The work support 10, the fixed structure 22, and the movable structure 21 define an internal space 101 of the compression tool 100. This internal space 101 is defined as follows: • vertically, between, on the one hand, the working surface 31 of the work support 30 and, on the other hand, the rectangular parallelepiped plate of the mobile structure 21; and • horizontally, or transversely, by the vertical guide columns 221 of the fixed structure 22.

[0053] According to the invention, the pressing plate 30 is connected to the mobile structure 21 of the reinforcement 20 by means of connection 25 comprising means of energy storage 26 disposed between the mobile structure 21 and the pressing plate 30 so as to prestress the pressing plate 30 with respect to the mobile structure 21 of the reinforcement 20, and at least one means of adjusting the prestress 27.

[0054] The pressing plate 30 is positioned in the internal space 101 of the compression tool 100, being generally transversely centered in this internal space. In other words, the pressing plate 30 is positioned so as to be substantially equidistant from the guide columns 221.

[0055] The pressing plate 30 has the shape of a rectangular parallelepiped plate whose horizontally extending pressing surface 31 is oriented opposite the working surface 11 of the work support. The pressing plate 30 also has an upper surface, opposite the pressing surface 31 and oriented opposite the parallelepiped plate of the mobile structure 21. The distance between this upper surface and the pressing surface of the pressing plate 30 vertically delimits its thickness.

[0056] The means for connecting the pressing plate 30 to the mobile structure 21 of the frame 20 include at least one guide rod 250, preferably at least three, here four guide rods 250, separate from the adjustment means 27, for guiding the vertical translation of the movement of the pressing plate 30 relative to the mobile structure 21.

[0057] Each of the guide rods 250 is secured, at one lower end, to the pressing plate 30, in particular to a pressing plate anchor 30 located on its upper surface, i.e. on the side opposite the pressing surface 31.

[0058] The mobile structure 21, in particular the parallelepiped-shaped plate of the mobile structure 21, has a plurality of orifices (not visible in the figures), each through which a vertically extending guide rod 250 passes, i.e. parallel to the vertical reference axis Z. The holes are through-holes and pass vertically through the plate of the moving structure 21 along its thickness. The guide rods 250 each have a cross-section configured to cooperate with one of the corresponding holes in the moving structure 21. Each guide rod 250 is thus in a sliding pivot or sliding connection with the corresponding hole in the moving structure 21. In this way, the pressing plate 30, extending parallel to a horizontal reference plane, is guided vertically in translation.

[0059] The interaction between a guide rod 250 and an associated through-hole locally forms a sliding or pivot connection and together constitute a means of guiding the pressing plate 30 in vertical translation relative to the moving structure 21.Thus, the linking means 25 include a sliding link between the pressing plate 30 and the mobile structure 21 obtained by the plurality of guide rods 250 cooperating through the complementary shaped holes of the mobile structure 21.

[0060] Thus, the pressing plate 30 is mobile relative to the mobile structure 21 along a single degree of freedom, corresponding to an axial translation along the vertical reference axis Z of the pressing plate 30 relative to the mobile structure 21.

[0061] In such a configuration, the pressing surface 30 is parallel with respect to the working surface 11 of the working support 10, regardless of the position of the pressing plate 30 with respect to the frame 20 and regardless of the position of the moving structure 21 with respect to the working support 10.

[0062] The connecting means 25 further include energy storage means 26 disposed between the movable structure 21 and the pressing plate 30 so as to pre-stress the pressing plate 30 relative to the movable structure 21 of the reinforcement 20

[0063] The energy storage means 26 comprise springs 260, preferably helical springs. In the illustrated embodiment, each guide rod 250 is surrounded by an associated helical spring 260 arranged coaxially, the associated helical spring 260 being interposed between the pressing plate 30 and the moving structure 21.

[0064] When a prestress is to be applied, the springs 260 are compressed and thus work in compression. This compression is obtained by bringing the pressing plate 30 closer to the movable structure 21 of the reinforcement 20.

[0065] The compression tool 100 further includes at least one preload adjustment means 27. Considering the springs 260, the adjustment means 27 is configured to allow adjustment of a spacing distance between the pressing plate 30 and the moving structure 21: this variation in the distance directly results in a variation of the stresses applied to the springs 260. Indeed, for a helical spring, the applied load and the height under load are directly correlated. depending on the stiffness of spring 260, in particular according to the following relationship: t _ AP ​​_ with: A “P2-L1 • k, the stiffness of the associated spring; • L1 the length of the spring under a load PI; and • L2, the length of the spring under a load P2.

[0066] The application of a prestress to the springs is thus obtained by decreasing the distance between the pressing plate 30 and the moving structure 21, a movement during which the springs 260 are compressed and prestressed.

[0067] One of the constraints of helical springs 260 is that they can flex according to the forces applied to them and thus deviate from their working axis, here vertical. To avoid such a phenomenon and to keep the springs 260 aligned in their working direction, the springs are positioned coaxially around each guide rod 250 so that each one surrounds one of the guide rods 250. Thus, in addition to guiding the movement of the pressing plate 30 relative to the moving structure 21, the guide rods 250 allow the deformation of the spring coils to be guided along their working direction, which is under compression.

[0068] The preload adjustment means 27 here comprises a threaded rod 270 connected to the press plate 30 and the movable structure 21. The threaded rod 270 extends vertically, parallel to the guide rods 250. The threaded rod 270 is fixedly attached to the press plate 30 at one of its lower ends and passes through a hole 210 in the movable structure 21. The adjustment means 27 also comprises a nut 271 cooperating with the threaded rod 270 on an outer side of the movable structure 21, opposite the inner side oriented towards the press plate 30. The nut 271, located on the side of one of the upper ends of the rod, opposite its lower end, retains the press plate 30.Indeed, the nut 271, cooperating with the threaded rod 270, allows the compression of the springs 260 to be retained, and at the same time, its rotation allows its axial position relative to the rod to be varied, and therefore its distance from its lower end, which is fixed to the pressing plate 30. The variation in the position of the nut 271 on the threaded rod 270 causes a variation in the distance between the pressing plate 30 and the movable structure 21, and therefore a variation in the load or preload of the associated springs 260.

[0069] The threaded rod 270 is positioned transversely in a space delimited by the connecting means 25, in particular by the guide rods 250. The threaded rod 270 is globally equidistant from the guide rods 250 and is located globally coaxially to a central axis of the compression tool 100.

[0070] As illustrated in Figures 2, 3 and 4, the compression tool 100 also includes an adjustment shim 40 configured to be positioned between the structure mobile 21 and the pressing plate 30. The adjusting wedge 40 has a predetermined thickness e depending on the energy storage means 26, i.e. springs 260, so as to be interposed between the mobile structure 21 and the pressing plate 30 in a predetermined prestressing position where the energy storage means 26 are constrained according to a predetermined force (or load).

[0071] Thus, knowing the stiffness of the springs 260, it is possible to determine a predetermined distance between the pressing plate 30 and the moving structure 21 which corresponds to the predetermined prestress applied on the springs 260. The springs 260, and more generally the energy storage means 26, are chosen so as to have an identical stiffness.

[0072] The use of an adjustment wedge 40 makes it very easy to ensure the positioning of the pressing plate 30 relative to the mobile structure 21.

[0073] The operation of the compression tool 100 will be better understood in light of the compression process described below and with reference to Figures 1 to 5.

[0074] In a rest state of the compression tool 100, the energy storage means 26 are in a relaxed position, i.e. in an unconstrained equilibrium state (see [Fig.1]).

[0075] Product 1 is positioned on the working surface 31 of the work plate 10 and directly above the pressing plate 30, as illustrated in [Fig. 2]. In this position before compression, product 1 is thus located vertically between the work plate 10 on one side and the pressing plate 30 on the other. These work plates 10 and pressing plate 30 form jaws to compress product 1 vertically. Care must be taken to position product 1 so as to be vertically aligned with the work plates 10 and pressing plate 30.

[0076] Once the product 1 is positioned in the compression tool 100, a step of adjusting the pressing plate 30 relative to the mobile structure 21 of the reinforcement 20 is implemented so as to position the pressing plate 30 in a predetermined prestressing position where the energy storage means 26 are constrained according to a predetermined force.

[0077] Such a step can be broken down more precisely into two sub-steps, which are successively: • a positioning step of the adjusting shim 40 between the moving structure 21 and the pressing plate 30 as illustrated in [Fig. 2], the adjusting shim 40 having a predetermined thickness e depending on the energy storage means 26 and more particularly the springs 260; and • a movement step of the pressing plate 30 towards the moving structure 21 until the predetermined preload position where the distance between the mobile structure 21 and the pressing plate 30 corresponds to the thickness e of the adjustment wedge 40.

[0078] During the step of moving the pressing plate 30 towards the movable structure 21, the nut is manipulated to tighten it in order to decrease its distance from the pressing plate 30 until the distance between the movable structure 21 and the pressing plate 30 corresponds to the thickness e of the adjusting shim 40, that is, until it comes into contact with the adjusting shim 40 (see [Fig. 2]). In other words, the nut 271 must be tightened to the correct position in which the adjusting shim 40 is interposed vertically between (without gap) the pressing plate 30 and the movable structure 21.

[0079] This step allows the springs 260 to be compressed until each one is in a state of prestress: in this state of prestress, the energy storage means 26 arranged between the mobile structure 21 and the pressing plate 30 work in compression and ensure a prestressing of the pressing plate 30 relative to the mobile structure 21 of the reinforcement 20.

[0080] Once the springs 260 are pre-stressed, a step is taken to move the movable structure 21 relative to the working support 10 so that the pressing plate 30 comes into contact with the product 1 to be compressed. The movement of the movable structure 21 allows for the concomitant movement of the pressing plate 30 to which it is attached, the latter being pre-stressed by the associated energy storage means 26 relative to the movable structure 21 of the reinforcement 20. During this movement of the movable structure 21, the pre-stress of the pressing plate 30 relative to the movable structure 21 remains unchanged, the adjustment means 27 being separate from the means 23 for moving the movable structure 21 relative to the working support 10.Thus, in this configuration, once the springs 260 are pre-stressed to the predetermined pressure, for example an equivalent pressure of 1 bar, the pressing plate 30 is lowered in the direction of its approach to the product until it comes into contact, without support or with negligible support, with the product 1.

[0081] Once the pressing plate 30 has been brought to the correct vertical position by the movement (vertical translation) of the mobile structure 21 relative to the working support 10, the clamping screws or clamping bolts of the locking means 24 are actuated to lock each of the connections or each of the degrees of mobility between the mobile structure 21 and the fixed structure 22. Such an operation makes it possible to lock the vertical position of the mobile structure 21 and to make it fixedly attached to the fixed structure 22, and therefore to the working support 10.

[0082] Next, a pre-determined preload release step, controlled by the adjustment means 27, is implemented, in particular by loosening completely loosen the nut 271 to obtain the release of the threaded rod 270 and release the predetermined prestress of the energy storage means 2 6.

[0083] When the force or preload compressing each of the springs 260 ceases, the springs 260 naturally tend to return to their natural position and thus transform their potential energy into kinetic energy. This kinetic energy tends to move the pressing plate 30, which is then held by the working support 10. Since the pressing plate 30 does not move, the springs retain their elastic potential energy: the pressing surface 31 and the upper surface of the product 1 being in contact with each other, they exert a normal reaction on each other of equivalent magnitude, so that the pressing plate 30 applies a pressure on the product 1 equal to the preload previously set by the adjustment means 27.

[0084] Thus, the springs 260 prestressed between the movable structure 21 and the pressing plate 30 work in compression until the adjustment means 27 release the stress so that the springs apply a resultant stress on the pressing plate 30 in the direction of a move away from the movable structure, and therefore in the direction of a move towards the fixing support 10. The product 1 being interposed between the working surface 11 and the pressing surface 31, the prestress of the spring is transmitted as a stress of identical magnitude to the product 1 compressed between the pressing plate 30 and the working support 10. The adjustment wedge 40 is then released and can be removed (see [Fig. 5]).

[0085] Thanks to the invention, it is thus possible to apply a prestress to energy storage means simply and precisely, and then release this prestress to apply it directly to the product 1 to be compressed. This compression tool 100 makes it possible to apply a stress to a product 1, such as a pocket-type cell, with a perfectly controlled, predetermined average pressure (here, 1 bar). This compression tool 100 is also capable of compressing products 1 of different bag thicknesses (from 3 mm to 14 mm) thanks to a simple adjustment mechanism. To do this, the compression tool 100 pushes the pressing plate 30 to 1 bar using the springs 260, which are prestressed to the correct force by means of the threaded rod 270 and the nut 271, forming a locking mechanism.

[0086] The displacement of the mobile structure 21 relative to the fixed structure 22 allows adaptability to different thicknesses without compromising on the quality and homogeneity or uniformity of the compression ensured.

[0087] Thanks to the invention, a compression tool 100 is thus obtained, ensuring the repeatability of the application of a given pressure, while being adaptable to products 1 to be compressed whose dimensional variability exists, while ensuring uniform pressure distribution. The invention as described therefore offers numerous advantages over the prior art, including: - improved adaptability to cell manufacturing tolerances; - the possibility of simply modifying the pressure to be applied without it being necessary to replace a part of the tool, by simply manipulating the preload adjustment means 27. - the direct application of pressure by the energy storage means 26 (springs 260) without depending on the coefficients of friction related to the tightening torque; - easy adaptation of the configuration to the different thicknesses and formats of the products to be compressed; - rapid pressure application, which reduces changeover times

[0088] Naturally, the invention is described above by way of example. It is understood that a person skilled in the art is able to carry out different embodiments of the invention without departing from the scope of the invention.

[0089] 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. Compression tool (100) for compressing a product (1), such as an electrode stack or an electric battery cell, the compression tool (100) being characterized in that it comprises at least: - a working support (10) having a working surface (11) configured to support the product (1) to be compressed; - an armature (20) comprising a movable structure (21) and means for moving the movable structure (21) relative to the working support (10); - a pressing plate (30) configured to come into contact and bear against the product (1) to be compressed in a working position in which the product (1) is compressed between the working support (10) and the pressing plate (30);the pressing plate (30) being connected to the mobile structure (21) of the reinforcement (20) by means of connection (25) comprising means of energy storage (26) disposed between the mobile structure (21) and the pressing plate (30) so as to prestress the pressing plate (30) with respect to the mobile structure (21) of the reinforcement (20), and at least one means of adjusting the prestress.

2. Compression tool (100) according to claim 1, characterized in that the pressing plate (30) has a pressing surface (31) configured to come into contact and bear against the product (1) to be compressed in the working position, the pressing surface (30) being parallel with respect to the working surface (11) of the working support (10), independently of the position of the pressing plate (30) with respect to the frame (20) and independently of the position of the moving structure (21) with respect to the working support (10).

3. Compression tool (100) according to claim 1 or 2, characterized in that: - the movable structure (21) is movable relative to the working support (10) along one degree of freedom, preferably a single one, corresponding to an axial translation along a vertical reference axis (Z), orthogonal to the working surface (11), of the mobile structure (21) with respect to the working support (10); and / or in that - the pressing plate (30) is mobile with respect to the mobile structure (21) along one degree of freedom, preferably unique, corresponding to an axial translation along the vertical reference axis (Z) of the pressing plate (30) with respect to the mobile structure (21).

4. Compression tool (100) according to any one of the preceding claims, characterized in that the preload adjustment means (27) includes a means for adjusting a spacing distance (de) between the pressing plate (30) and the moving structure (21).

5. Compression tool (100) according to the preceding claim, characterized in that the preload adjustment means (27) comprises a threaded rod (270) connected to the pressing plate (30) and to the movable structure (21), preferably fixedly attached to the pressing plate (30) and passing through a hole (210) in the movable structure (21), the adjustment means (27) comprising a nut (271) cooperating with the threaded rod (270) on an outside side of the movable structure (21), opposite the inside side oriented towards the side of the pressing plate (30).

6. Compression tool (100) according to claims 3, 4 and 5, characterized in that the connecting means (25) comprise at least one guide rod (250) separate from the adjusting means, preferably separate from the threaded rod (270), to guide in translation the movement of the pressing plate (30) relative to the moving structure (21).

7. Compression tool (100) according to any one of the preceding claims, characterized in that the frame (20) is integral with the working support (10), the frame (20) comprising a fixed structure (22) fixedly integral with the working support (10), the movable structure (21) being movable relative to the fixed structure (22).

8. Compression tool (100) according to the preceding claim, characterized in that the movement means (23) comprise a sliding link between the moving structure (21) and the fixed structure (22) and locking means (24) of the moving structure (21) relative to the fixed structure (22) configured to immobilize the mobile structure (21) relative to the fixed structure (22).

9. Compression tool (100) according to any one of the preceding claims, characterized in that the energy storage means (26) comprise at least one, preferably a plurality of, spring(s) (260), preferably helical springs.

10. Compression tool (100) according to the preceding claim, characterized in that each guide rod (250) is surrounded by an associated coaxially arranged helical spring (260), the helical spring (260) being disposed between, preferably interposed between, the pressing plate (30) and the moving structure (21).

11. Compression tool (100) according to any one of the preceding claims, characterized in that it comprises at least one adjustment shim (40) configured to be positioned, between the moving structure (21) and the pressing plate (30), the adjustment shim (40) having a predetermined thickness (e) as a function of the energy storage means (26) so as to be interposed between the moving structure (21) and the pressing plate (30) in a predetermined prestressing position where the energy storage means (26) are constrained according to a predetermined force.

12. A method for compressing a product (1), such as an electrode stack or an electric battery cell, by means of a compression tool (100) according to any one of the preceding claims, characterized in that the compression method comprises at least: - a step of adjusting the pressing plate (30) relative to the movable structure (21) of the armature (20) so as to position the pressing plate (30) in a predetermined prestressed position where the energy storage means (26) are constrained according to a predetermined force; - a step of moving the movable structure (21) relative to the working support (10) so that the pressing plate (30) comes into contact with the product (1) to be compressed; and - a pre-stress release step predetermined by the control of the adjustment means (27).

13. A method for compressing a product (1) according to the preceding claim, characterized in that the step of adjusting the pressing plate relative to the movable structure (21) of the frame (20) comprises - a step of positioning an adjustment shim (40) between the moving structure (21) and the pressing plate (30), the adjustment shim (40) having a predetermined thickness (e) depending on the energy storage means (26); and - a step of moving the pressing plate (30) towards the moving structure (21) to the predetermined prestressing position where the distance between the moving structure (21) and the pressing plate (30) corresponds to the thickness (e) of the adjustment shim (40).