Device for gripping a module of electrochemical elements

Abstract

The invention relates to a gripping device (1), comprising: - a rod (2) provided with a first stop (3) and a second stop (4), - a polymer sleeve (5) through which the rod passes and which has a first end (6) and a second end (7), the first end (6) being in contact with the first stop; - a first pressure part (8) configured to apply a pressure to the second end (7) of the sleeve (5); - a spring (9) through which the rod passes and which is arranged between the first pressure part (8) and the second stop (4); and - a means (10) for compressing the spring, wherein action on the means for compressing the spring leads, via the first pressure part (8), to a shrinkage in the length of the sleeve in the axial direction and to an expansion of the sleeve in the radial direction.

Description

Description Title: Device for gripping a module of electrochemical elements Technical field of the invention

[0001] The technical field of the invention is that of devices used for gripping a module of electrochemical elements. It also relates to the field of lifting tools enabling the simultaneous lifting of a battery consisting of a plurality of modules of electrochemical elements. Context of the invention

[0002] A battery is made up of several electrochemical cells, referred to as cells in the following text, connected together and electrically. Connecting several electrochemical cells in series adds their voltages to achieve the desired operating voltage for the battery. Connecting several cells in parallel adds their capacities to achieve the desired operating capacity for the battery. Constructing a battery may require a large number of cells when the voltage or capacity of a single cell is low compared to the desired voltage and capacity for the battery.

[0003] Forming a battery by assembling individual cells onto a common support is a long and tedious task. Therefore, modules are generally manufactured beforehand, consisting of several electrically connected cells, and these modules are then attached to a common support, which serves as the battery base. Each module can, for example, contain 3, 4, 5, or 6 cells. It constitutes a unit of fixed volume, delivering a predetermined voltage and energy output, which depend on the electrical connection of the cells within the module.

[0004] Moving a module requires a specific tool because the module can be quite heavy and must be lifted safely. A gripping tool is necessary to ensure the module is lifted without risk of falling.

[0005] Gripping tools exist. Some consist of two flat jaws that clamp onto two opposite faces of an object. Examples include documents GB 0 011 863, GB 2 105 631, US 2007 / 0046048, and US 4,968,077. However, these tools do not allow the module to be gripped from above. Yet, gripping the module from above would be advantageous because the underside of the module is inaccessible, as the module rests on a support. Tools are needed that allow the module to be lifted. The module can be lifted by gripping the top of the module. One way to lift a module from the top is to use a bore on its upper surface. An additional constraint is that this bore may have a smooth wall, meaning it lacks notches, threads, locking mechanisms, or any other means of attachment. In this case, the gripping tool must be able to bear against this smooth wall.

[0006] There are tools that grip the smooth walls of a bore and exert pressure on the bore walls in a radial direction. One example is a clamping sleeve. The sleeve is inserted into the bore, and its diameter is increased using a screw. By increasing the sleeve's diameter, the frictional force between the sleeve and the bore surface is amplified until it is sufficient to counteract the module's weight. This type of sleeve requires screwing each sleeve onto the bore, which lengthens the preparation time needed to lift the module.

[0007] There are also plier-shaped tools. The jaws of the pliers act like claws that spread apart and grip diametrically opposite points on the bore. This solution is also unsatisfactory because the jaws of the pliers scratch the bore wall, given the significant radial force applied to the walls of the module cavity.

[0008] We are therefore looking for a way to grasp a module that: - allows the module to be gripped from above, - offers sufficient frictional force to lift the module, even when the gripping means is in contact with a smooth surface of the module, - does not damage the surface it is placed in contact with, - does not require screwing, locking or snapping onto the module, - maintains a good grip quality of the module and compensates for any event that could impair this good grip quality.

[0009] Furthermore, it is desirable that the operator have a lifting tool available to lift a battery resulting from the combination of a large number of modules, for example 10 or 20 modules at a time. Summary of the invention

[0010] To this end, the invention proposes a gripping device comprising: - a rod equipped with a first stop and a second stop, - a polymer sleeve through which the rod passes and which has a first and a second end, the first end being in contact with the first stop, - a first pressure piece configured to exert pressure on the second end of the sleeve, - a spring through which the rod passes and which is positioned between the first pressure piece and the second stop, - a means for compressing the spring, an action on the means for compressing the spring causing, via the first pressure piece, a narrowing of the length of the sleeve in the axial direction and an expansion of the sleeve in the radial direction.

[0011] The invention is based on the exploitation of the restoring force of a spring in the stressed state to maintain a compression applied to the two ends of a deformable polymer sleeve introduced into a cavity of the object to be lifted.

[0012] Under the applied compression, the sleeve's length decreases. Since the sleeve is incompressible, it expands radially. This radial expansion creates a frictional force against the wall of the object's cavity. The greater this frictional force, the greater the device's capacity to lift heavy objects. By varying the spring's return force, this frictional force can be adjusted to suit the mass of the object being lifted. Furthermore, the return force of the pre-stressed spring maintains a consistent level of friction between the device and the object, compensating for potential fluctuations in parameters that affect the quality of the object's support, such as the sleeve's chemical composition, its aging condition, and the distance between the sleeve's outer surface and the object's cavity wall.

[0013] According to one embodiment, the means for compressing the spring comprises: - a second pressure piece through which the rod passes and which is located between the first pressure piece and the second stop, - a means to allow the movement of the second pressure piece between the first pressure piece and the second stop, for example a cam.

[0014] According to one embodiment, the spring is disposed between the second pressure piece and the second stop, and the means for enabling the movement of the second pressure piece is configured to bring the second pressure piece closer to the second stop, thus compressing the spring.

[0015] According to one embodiment, the spring is disposed between the first and second pressure piece and the means for enabling the movement of the second pressure piece is configured to bring the second pressure piece closer to the first pressure piece, thus compressing the spring.

[0016] According to one embodiment, the rod is threaded, and - either the means for compressing the spring comprises a nut screwed onto the threaded rod and the second pressure piece is a ring, the rotation of the nut allowing a displacement of the ring along the threaded rod and an adjustment of the length of the spring, - either the means to compress the spring is a threaded ring screwed onto the threaded rod.

[0017] According to one embodiment, the polymeric sleeve is made of silicone.

[0018] According to one embodiment, at least one of the first or second pressure piece is a washer whose inner diameter is traversed by the rod.

[0019] According to one embodiment, the inner edge of the washer includes a centering ring to center the position of the spring on the rod.

[0020] The invention also relates to a lifting tool comprising a plurality of gripping devices as described above.

[0021] According to one embodiment, the means for compressing the springs of the plurality of gripping devices comprises: - a second pressure piece through which the rod passes and which is located between the first pressure piece and the second stop, - a means to allow the second pressure piece to move between the first pressure piece and the second stop, for example a cam, and - all the second stops of the plurality of gripping devices are fixed to an upper plate of the lifting tool, - The entire set of initial pressure parts of the plurality of gripping devices is fixed to a lower plate of the lifting tool, - all the secondary pressure pieces of the plurality of gripping devices are fixed to an intermediate platform located between the upper platform and the lower platform.

[0022] According to one embodiment, the lifting tool comprises one or more arms configured to drive in rotation one or more cams located between the lower plate and the intermediate plate, the rotation of said one or more cams enabling the movement of the intermediate plate and the compression of the springs of the plurality of gripping devices.

[0023] According to one embodiment, the springs of the plurality of gripping devices are arranged between the upper plate and the intermediate plate and the rotation of said one or more cams causes the compression of the springs of the plurality of gripping devices between the upper plate and the intermediate plate.

[0024] The invention also relates to an assembly comprising: - the lifting tool as described above, and - a plurality of electrochemical element modules, each electrochemical element module comprising at least one cavity, the cavity receiving one end of the stem of a gripping device.

[0025] According to one embodiment, the cavity has walls without notches, threads, snap-on means or means for attaching the rod of the gripping device in the cavity.

[0026] According to one embodiment, the cavity opens onto an upper wall of the module.

[0027] According to one embodiment, the upper platform is equipped with sling attachment means for lifting the assembly. Brief description of the figures

[0028] Embodiments of the invention are described below in more detail with reference to the figures below.

[0029] [Fig. 1] is a cross-sectional view of the gripping device according to a first embodiment of the invention. The diagram on the left shows the pressure device for a spring in an uncompressed state. The diagram on the right shows the pressure device for a spring in a compressed state.

[0030] [Fig. 2] is a cross-sectional view of the gripping device according to a second embodiment of the invention. The diagram on the left shows the pressure device for a spring in an uncompressed state. The diagram on the right shows the pressure device for a spring in a compressed state.

[0031] [Fig.3] is a cross-sectional view of the gripping device according to a third embodiment of the invention.

[0032] [Fig.4] is a cross-sectional view of the first pressure piece, which features a centering ring.

[0033] [Fig.5] is a perspective view of a lifting tool in which the arms are in the open position and the springs of the gripping devices are not compressed.

[0034] [Fig.6] is a perspective view of a lifting tool in which the arms are in the closed position, which has the effect of compressing the springs of the gripping devices.

[0035] [Fig. 7] is a perspective view of a battery made up of an assembly of several modules of electrochemical elements. This view shows, in particular, the upper surface of the modules. Each upper surface has a cavity for the insertion of a gripping device.

[0036] [Fig.8] is a perspective view of a lifting tool after the gripping devices have been placed in the cavities located on the upper surface of the modules and the springs of the gripping devices have been compressed. Description of embodiments of the invention

[0037] The gripping device according to the invention will be described below with reference to Figures 1 to 4. The device (1) is intended to be inserted into a cavity (34) located on an upper face (32) of the object (31) to be lifted. The device is advantageously used to lift a module of electrochemical elements (31), for example, of the lithium-ion type, but it is understood that it can be used to lift any object, provided that the shape and dimensions of the sleeve correspond to those of the cavity in that object.

[0038] The cavity of the module may be located on a component that serves as a common support for the electrochemical elements (31). This may be a bore (34) formed through the cross-section of a beam that supports the elements. The cross-section of the gripping device's stem and the cross-section of the cavity are preferably circular. The cavity wall is preferably smooth. "Smooth" means a wall free of notches, threads, snap-fit ​​means, grooves, or any means of attaching the gripping device's stem to the cavity.

[0039] The rod (2) of the device may be made of a single piece, with or without portions of different diameters. It may also be made by fitting two pieces (2.1, 2.2) or more pieces together, with the same or different diameters. In one embodiment, the rod is made of two pieces (2.1, 2.2) of different diameters together. The rod has a first stop (3) at one end and a second stop (4) at the opposite end. The end of the device containing the first stop is inserted first into the cavity (34) of the object to be lifted. The first stop may be a bulge on the end of the rod. Preferably, the bulge has an oblong shape to facilitate insertion of the device into the cavity.

[0040] One end (6) of the sleeve (5) rests against this bulge (3). The sleeve is preferably cylindrical. The outer diameter of the sleeve is adapted to the diameter of the cavity and is such that it allows the sleeve to enter the cavity of the object before the sleeve is compressed in its longitudinal direction. The outer diameter of the sleeve is slightly smaller than the diameter of the cavity. It must not be too small relative to the diameter of the cavity, as this would create insufficient friction with the cavity of the object to be lifted. It must not be too close to the diameter of the cavity, as this would cause resistance to the insertion of the tool into the cavity. The diameter of the sleeve is preferably equal to the diameter of the bulge at its widest point.

[0041] A first pressure piece (8) is placed on the end of the sleeve (7) opposite the end (6) in contact with the bulge (3). It is movable on the rod (2.1). Its movement towards the first stop (3) allows a compressive force to be applied to the sleeve along its longitudinal axis, as the sleeve is clamped between the first stop (3) and the first pressure piece (8). The compression exerted by the first pressure piece (8) causes a reduction in the length of the sleeve (7) and its expansion in the radial direction within the cavity of the object. The radial expansion of the sleeve creates a frictional force directed radially within the cavity. The frictional force between the sleeve and the cavity is greater than the weight of the object, which allows the object to be lifted and held in its raised position.

[0042] The sleeve (5) is preferably made of an elastomeric material therefore A certain degree of elasticity, for example silicone, and a high frictional force with the cavity material (34) against which it is in contact are required. The length of the sleeve (5) is determined by a person skilled in the art based on the nature of the sleeve material and the mass to be lifted. Increasing the sleeve length increases the frictional forces with the cavity and allows for lifting heavier objects. As an order of magnitude, a silicone sleeve 20 to 30 mm long can lift, without irreversible slippage (i.e., in a linear region where force and displacement are related), a mass of up to 3 kg, taking into account a safety factor of 3, and a safety factor of 5 in the case of irreversible slippage (i.e., in a non-linear region where force and displacement are related).

[0043] The spring used (9) is preferably helical. Its coils surround a portion (2.2) of the outer surface of the rod. An operator applies a compressive force to the spring. In response to this compressive force, the spring exerts a restoring force that acts in the longitudinal direction of the sleeve (5). This restoring force is equal to the product of the spring constant and the difference between the length of the spring in its compressed state and its uncompressed length. This restoring force is used to compress the sleeve, as explained above.

[0044] The presence of the spring (9) maintains the axial force on the sleeve (5) despite any changes that may occur in the friction zone between the object to be lifted and the tool. For example, aging of the sleeve material could lead to hardening and less pronounced radial expansion within the object's cavity, resulting in a less secure hold between the sleeve and the cavity and the object becoming dislodged. Variability in the bore manufacturing process could lead to variations in the bore diameter, also resulting in a less secure hold between the sleeve and the cavity. Finally, the mass of the object to be lifted could also vary. The spring (9) compensates for any relaxation or displacement of the parts involved by continuing to apply a force along the longitudinal axis of the sleeve (5), which is positioned between the first stop (3) and the first pressure piece (8).

[0045] Simply moving the sleeve between the first stop (3) and the first pressure piece (8) does not guarantee sufficient hold between the sleeve and the cavity to keep the object in the raised position. The invention makes it possible to maintain a compressive force on the sleeve by means of the spring.

[0046] The means used by the user to compress the spring includes: - a second pressure piece (11) through which the rod passes and which is located between the first pressure piece (8) and the second stop (4), - a means (10) to allow the second pressure piece (11) to move between the first pressure piece (8) and the second stop (4).

[0047] The spring (9) can exert its restoring force indirectly on the first pressure piece (8). In this case, the spring is positioned between the second stop (4) and the second pressure piece (11). A means allows the second pressure piece (11) to be brought closer to the second stop (4) and the spring (9) to be compressed. This means (10) can be positioned between the first pressure piece (8) and the second pressure piece (11). It maintains a predetermined distance between the first and second pressure pieces. This distance is proportional to the compressive force that the operator wishes to apply to the spring, i.e., the spring preload. The restoring force of the spring is transmitted to the first pressure piece (8) via the means (10) to move the second pressure piece (11). The first pressure piece then transmits the restoring force of the spring to the sleeve (5).One such embodiment is shown in Figure 1.

[0048] The spring (9) can exert its restoring force directly on the first pressure piece (8). In this case, the spring is positioned between the first pressure piece (8) and the second pressure piece (11). A means (10) brings the second pressure piece (11) closer to the first pressure piece (8) and compresses the spring. This means can be positioned between the second pressure piece (11) and the second stop (4). It maintains a predetermined distance between the second pressure piece (11) and the second stop (4). This distance is proportional to the compressive force that the operator wishes to apply to the spring. Unlike the embodiment shown in Figure 1, the restoring force of the spring is applied directly to the first pressure piece, which then transmits it to the sleeve. Such an embodiment is shown in Figure 2.

[0049] The means (10) for moving the second pressure piece can be a cam. Alternatively, the means for moving the second pressure piece can be a nut (10) screwed onto a threaded hole on the outer surface of the rod (2), as illustrated in Figure 3. Rotating the nut allows it to move along the rod. This movement of the nut changes the position of the second pressure piece (11) on the threaded rod, thereby altering the compression state of the spring. The second pressure piece (11) can be a ring. The ring can also have a threaded hole allowing it to move along the rod and locking its position on the screw. The threaded ring then combines the function of a second pressure piece and a means for moving the second pressure piece.

[0050] The first pressure piece (8) may be a washer or a plate having an opening, for example, a circular one. The rod (2) is inserted through the inner diameter of the washer or the opening in the plate and can slide through the opening. The surface of the washer or plate extends perpendicularly to the rod and receives the restoring force of the spring, which is applied along the direction of the rod. The edges of the opening may have a shoulder (35), also called a centering ring, intended to guide the spring's restoring force on the rod, as shown in Figure 4. The centering ring reduces the risk of spring buckling, keeps the plate or washer perpendicular to the rod, especially when the spring is highly compressed, and thus improves the quality of the contact between the sleeve and the cavity wall. The centering ring (35) is positioned against the inside of the first coil of the spring (9). The centering ring may not be necessary if the diameter of the rod at the location (2.2) where the spring is positioned is large enough to act as a centering device itself and prevent spring buckling. The flat surface of the plate or washer can be in direct contact with the end of the sleeve.

[0051] Preferably, a guide (36) is fixed to the opening of the plate or washer (8). It extends along the length of the rod. Its purpose is to guide the rod (2) within the plate (8) and to provide clearance (and support) between the lifting tool and the battery to be lifted. The length to be chosen is up to each user. A key feature of the guide is that its end length (33) is sufficient to ensure that the sleeve (5) is fully inserted into the cavity and is positioned at a minimum distance from the cavity opening before the sleeve is compressed. Thus, if the sleeve slips slightly out of the cavity after it has expanded, it will not protrude. Even partial withdrawal of the sleeve (5) from the cavity would result in a loss of friction between the sleeve and the cavity wall (34).Sufficient length of the guide end (33) ensures that compression of the sleeve is not lost due to the withdrawal of part of the sleeve's volume from the cavity. A second advantage of sufficient guide end length (33) is that it prevents bulging during tool insertion should the sleeve end be too close to the cavity opening. A further characteristic of the guide is that the guide end (33) in contact with the sleeve preferably has the same shape and diameter as the sleeve (5). If the guide end (33) has a diameter larger than that of the sleeve (5), there is a risk that the guide will abut against the cavity opening (34). Conversely, if the end (33) of the guide (36) has a diameter smaller than that of the sleeve (5), there is a risk that part of the upper part of the sleeve will escape from the cavity and form a hernia outside the cavity.

[0052] The gripping device can be released from the object by releasing the compression applied to the spring. With the sleeve no longer axially compressed, it returns to its original length and diameter. Retracting the sleeve radially eliminates frictional forces with the cavity.

[0053] The combination of several gripping devices (1) makes it possible to constitute a lifting tool (20). The lifting tool can be used to simultaneously lift a plurality of modules of electrochemical elements (31) intended to be assembled into a battery. The lifting tool comprises a frame. This frame includes at least three parallel plates (21, 22, 23): a lower plate (22), an upper plate (21), and an intermediate plate (23) positioned between the lower and upper plates. The lower plate (22), representing the first pressure element (8) as shown in Figure 1, has a plurality of holes. The guide (36) of the gripping device is fixed to each hole. The intermediate plate (23), representing the second pressure element (11) as shown in Figure 1, has a plurality of holes aligned with the holes in the lower plate. The upper plate (21) has a plurality of holes aligned with the holes in the intermediate and lower plates. Each hole in the plate (21) constitutes the second stop (4) for the gripping device fixed to it.

[0054] The intermediate plate (23) is vertically movable. It can move upwards towards the upper plate (21) and compress the springs, according to the operating mode illustrated in Figure 1. It can also move downwards towards the lower plate (22) and compress the springs, according to the operating mode illustrated in Figure 2. In both operating modes, a movement of the intermediate plate results in the compression of all the springs of the gripping devices and a radial expansion of all the sleeves in the module cavities, allowing all the modules to be gripped at once.

[0055] The movement of the intermediate platform can be actuated by the rotation of a cam located between the lower platform (22) and the intermediate platform (23) in the embodiment illustrated in Figure 1, or between the intermediate platform (23) and the upper platform (21) in the embodiment illustrated in Figure 2. The cam can be attached to an arm (24). A rotational movement of the arm (or arms, depending on the embodiment) causes a rotation of the cam (10), which imparts a vertical upward or downward displacement to the intermediate platform (23) (parallel translation of (23) relative to (22)). This displacement can be a few centimeters. The vertical displacement of the platform corresponds to the length of the spring's contraction. Therefore, the spring's restoring force can be varied to adapt it to the mass of the load to be lifted by varying the displacement height of the intermediate platform and thus the cam's profile.

[0056] To distribute the force required to overcome the resistance of the springs, two cams are preferably positioned at opposite ends of the frame. The movement of the two arms can be a rotation of approximately 90° from a nearly vertical to a nearly horizontal orientation. Figure 5 shows the lifting tool when the arms (24) are in the open position and the springs of the gripping devices are not compressed. The arms are then rotated approximately 90° to bring them to the closed position. Figure 6 shows the lifting tool when the arms are in the closed position and the springs of the gripping devices are tablets. During the rotation of the arms, the cam associated with each arm also rotates 90°. This rotational movement of the cam results in a vertical translation of the intermediate plate, either upwards or downwards. The intermediate plate moves a distance corresponding to the shortening distance of each of the gripping device springs.

[0057] The upper platform (21) may have attachment points at its four corners for a means of attaching the lifting tool to a lifting device such as a crane, winch, or forklift. This means of attaching the lifting tool may be slings (25). Once the lifting tool is locked onto the battery by compressing the springs, the lifting tool can be attached to the lifting device, and the entire assembly consisting of the lifting tool and the battery can be lifted. Battery description:

[0058] A battery consists of several modules of electrochemical cells assembled and electrically connected. The electrochemical cells are held together within a single module using one or more flanges. A flange is a plate with multiple recesses across its largest surface, designed to fit into the base of the cell container and / or the cell lid. Each recess conforms to the shape of the cross-section of the cell container or lid. In addition to assembling the cells within a module, the flange also secures the electrochemical cells, preventing them from being damaged by vibrations. The flange is generally made of an electrically insulating material, preferably plastic. It is usually produced by molding a plastic material.For better support of the components, two flanges are preferably used; one is fitted onto the covers of the module components, and the second is fitted onto the bases of the components.

[0059] The upper surface of the modules has a cavity. This cavity can be a bore machined along the longitudinal axis of the beam. This beam serves as a common support for the electrochemical elements of the module. It preferably has a circular cross-section.

[0060] Figure 7 is a perspective view of a battery consisting of an assembly of ten modules of electrochemical elements (31). Each module consists of the assembly and electrical connection of four elements. The elements are held together by an upper flange (32) and a lower flange (37). The upper surface of the modules is formed by the upper flange. The figure shows, in particular, the upper surface (32) of the modules. A cavity (34) is visible on the upper surface (32) of each module. This cavity serves for the insertion of a gripping device according to the invention.

[0061] To lift the battery, the lifting tool is placed above it. The ends of the gripping tool's rods are positioned vertically above the cavities. The lifting tool is then lowered to insert the rod ends into the cavities. The lifting tool's arms are actuated to move the intermediate platform. This platform moves either upwards in the embodiment shown in Figure 1, or downwards in the embodiment shown in Figure 2. The rotational movement of the arms causes the intermediate platform to move a distance corresponding to the desired shortening distance of each of the gripping device's springs, as explained above.Figure 8 is a perspective view of a lifting tool after the gripping devices have been placed in the cavities located on the upper surface of the modules, the arms have been closed and the springs of the gripping devices have been compressed.

Claims

Demands

1. Gripping device (1) comprising: - a rod (2) equipped with a first stop (3) and a second stop (4), - a polymer sleeve (5) through which the rod passes and which has a first (6) and a second end (7), the first end (6) being in contact with the first stop, - a first pressure piece (8) configured to exert pressure on the second end (7) of the sleeve (5), - a spring (9) through which the rod passes and which is arranged between the first pressure piece (8) and the second stop (4), - a means (10, 11) for compressing the spring, an action on the means for compressing the spring causing, via the first pressure piece (8), a narrowing of the length of the sleeve in the axial direction and an expansion of the sleeve in the radial direction.

2. Gripping device (1) according to claim 1, wherein the means for compressing the spring comprises: - a second pressure piece (11) through which the rod passes and which is located between the first pressure piece (8) and the second stop (4), - a means (10) for enabling the movement of the second pressure piece (11) between the first pressure piece (8) and the second stop (4), for example a cam.

3. Gripping device (1) according to claim 2, wherein the spring (9) is disposed between the second pressure piece (11) and the second stop (4) and the means (10) for enabling the movement of the second pressure piece is configured to bring the second pressure piece (11) closer to the second stop (4) thus achieving compression of the spring.

4. Gripping device (1) according to claim 2, wherein the spring (9) is disposed between the first (8) and the second (11) pressure piece and the means (10) for enabling the movement of the second pressure piece is configured to bring the second pressure piece (11) closer to the first pressure piece (8) thereby achieving compression of the spring.

5. Gripping device (1) according to claim 4, wherein: - the rod is threaded, and - either the means for compressing the spring comprises a nut (10) screwed onto the The threaded rod and the second pressure piece is a ring; rotating the nut allows the ring to move along the threaded rod and the spring length to be adjusted. - either the means to compress the spring is a ring (11) tapped and screwed onto the threaded rod.

6. Gripping device (1) according to any one of the preceding claims, wherein the polymeric sleeve (5) is made of silicone.

7. Gripping device (1) according to any one of the preceding claims, wherein at least one of the first (8) or second (11) pressure piece is a washer whose inner diameter is traversed by the rod.

8. Gripping device (1) according to claim 7, wherein the inner edge of the washer includes a centering ring (35) for centering the position of the spring on the rod.

9. Lifting tool (20) comprising a plurality of gripping devices (1) according to any one of claims 1 to 8.

10. Lifting tool (20) according to claim 9, wherein the means for compressing (10) the springs of the plurality of gripping devices (1) is such as described in claim 2, and - all the second stops (4) of the plurality of gripping devices are fixed to an upper plate (21) of the lifting tool, - the set of first pressure parts (8) of the plurality of gripping devices is fixed to a lower plate (22) of the lifting tool, - the set of second pressure pieces (11) of the plurality of gripping devices is fixed to an intermediate plate (23) located between the upper plate and the lower plate.

11. Lifting tool (20) according to claim 10, comprising one or more arms (24) configured to drive in rotation one or more cams located between the lower plate (22) and the intermediate plate (23), the rotation of said one or more cams enabling the movement of the intermediate plate and the compression of the springs (9) of the plurality of gripping devices (1).

12. Lifting tool (20) according to claim 11, wherein the springs (9) of the plurality of gripping devices (1) are disposed between the upper plate (21) and the intermediate plate (23) and the rotation of said one or more cams causes the compression of the springs (9) of the plurality of gripping devices between the upper plate and the intermediate plate.

13. Set (30) comprising: - the lifting tool (20) according to any one of claims 9 to 12, and - a plurality of electrochemical element modules (31), each electrochemical element module comprising at least one cavity (34), the cavity receiving one end of the rod (2) of a gripping device.

14. Assembly (30) according to claim 13, wherein the cavity (34) has walls without notch, thread, snap-on means or hooking means for the stem of the gripping device in the cavity (34).

15. Assembly (30) according to claim 14, wherein the cavity (34) opens onto an upper wall (32) of the module.

16. Assembly (30) according to any one of claims 13 to 15, wherein the upper platform (21) is provided with sling attachment means (25) for lifting the assembly.

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