Protection device against the propagation of thermal runaway in a battery

Abstract

A battery (1) comprising: - at least two parallelepiped-shaped electrochemical elements (2-1, 2-2), - a first layer (3-1) of a refractory material resistant to temperatures up to 1200°C, disposed in contact with the entirety of a first face, which is one of the largest faces (4) of one (2-1) of the electrochemical elements, said first layer having a central region (C) centered on the center of the first layer and having an area representing 30 to 60% of the area of ​​said first face; - a rigid spacer (5) having a hardness greater than or equal to 90 Shore A according to ASTM D 2240-15(2021), disposed between said first layer and the second electrochemical element (2-2), the rigid spacer being located outside the central region of said first layer. (Shorthand figure: Figure 1)

Description

Title of the invention: Device for protection against the propagation of thermal runaway in a battery Technical field of the invention

[0001] The invention relates to the technical field of devices for protection against the propagation of thermal runaway in a battery of electrochemical elements. Context of the invention

[0002] A battery of electrochemical elements comprises a plurality of electrochemical elements, hereinafter referred to as "element(s)," which are assembled side by side in a common grouping case. This case is intended to hold the elements in a fixed position during transport or use of the battery.

[0003] During the charging of a hermetically sealed lithium-ion cell, the cell container swells. In the case of a parallelepiped-shaped cell (synonymous with a prismatic cell), the swelling occurs primarily on the two largest opposing lateral flat faces of the container. This swelling increases as the cell's state of charge approaches a fully charged state. Since the cells are stacked end-to-end in the battery compartment and each cell undergoes an increase in thickness, a significant increase in the total battery length is observed, resulting from the sum of the increases in cell thickness.However, since the bulkhead container is generally made of a rigid material and the free space between the components and the container walls is limited, the swelling of the components subjects the container walls to pressure forces that can lead to irreversible deformation or even damage. Therefore, a device is often used to prevent the container from deforming due to the swelling of the components during loading.

[0004] Furthermore, an anomaly in the operation of the battery may be caused by the malfunction of one of the elements (short circuit, overload, etc.) or by an external disturbance (shock, temperature rise, etc.) or by a failure of the electronic system managing the state of charge or other parameters of the battery elements.

[0005] For example, when a lithium cell is subjected to an overload, its temperature increases. The temperature increase leads to an increase in the charging current, which further increases the temperature. If the cell does not If the battery lacks a sufficient cooling system to dissipate the heat generated, it experiences thermal runaway: the temperature increase is fueled by the cell itself. This uncontrolled temperature rise leads to the generation of gases, which can cause an increase in the cell's internal pressure, triggering a safety gas venting system. If these hot gases, which can reach temperatures of 650°C, are released, they come into contact with the other battery cells. There is then a risk that the thermal runaway phenomenon will spread to all the battery cells, leading to the total destruction of the battery.

[0006] We are therefore looking for a device which prevents the trunk from deforming under the effect of the swelling of the elements during their charging and which also prevents the propagation of a thermal runaway between the elements of the battery.

[0007] Document EP-A-3 208 866 describes a system for compensating for cell swelling in a battery. This system comprises a rigid spacer and a flexible spacer interposed between two adjacent cells. The rigid spacer can be positioned at the periphery of the largest face of the cells. Its function is to maintain a constant distance between the two adjacent cells. The flexible spacer can be positioned near the center of the largest face of the cells. Its function is to absorb the increase in thickness of the two cells during their charging. As shown in Figure 2b of this document, this system makes it possible to maintain a constant battery length in the event of cell swelling. In a preferred embodiment, the flexible spacer is made of a material with low thermal conductivity. This has the advantage of preventing the heat generated by this element from propagating to the adjacent cells.To improve safety, there is a need for the inter-element spacer to withstand very high temperatures.

[0008] Document EP-A-2 994 947 describes a battery comprising a first and a second prismatic element between which is placed a layer of a material resistant to a temperature of 300°C. This material is not in contact with the entire external wall surface of the container of the two elements. Indeed, two spacers placed between the containers of the two elements at their upper and lower parts maintain the material resistant to a temperature of 300°C at a certain distance from the wall of the container of the elements. The combination of the layer of material resistant to a temperature of 300°C and the two spacers is presented as constituting a thermal barrier against the propagation of a thermal runaway. This solution is not, however, entirely satisfactory because it is noted that the layer of material resistant to a temperature of 300°C is not in contact with the wall of the container of the elements.There are two layers of air on either side of the layer of material resistant to a temperature of 300°C. On the one hand, these air layers can facilitate the... Heat transfer to neighboring cells is reduced. Furthermore, they increase the battery's length. The fact that the 300°C-resistant material is not in contact with the entire surface of the cells means that its thermal barrier properties cannot be fully utilized. In addition, as the cells expand, the 300°C-resistant material layer tends to compress under the force exerted by the cells, thus reducing its insulating properties. Finally, it is recommended to use spacers with some flexibility to conform to the shape of the cell surfaces. Because both the 300°C-resistant material layer and the spacers tend to compress under the cells, the spacing between the terminals of two adjacent cells decreases.The electrical connection between two adjacent elements must therefore be flexible in order to absorb the variation in the inter-element distance. However, such flexible connections are more complex in design than rigid connections in the form of simple metal bars.

[0009] US patent 9,324,982 describes a system for compensating for the swelling of cells in a battery and ensuring their cooling. A barrier is placed between two cells. It consists of an outer part in contact with the periphery of the largest surface area of ​​the cells and an inner part in contact with the center of the largest surface area of ​​the cells. The outer part is rigid and maintains a constant spacing between two adjacent cells. The inner part is flexible and absorbs the increase in volume of the two adjacent cells. The opposite faces of the outer and inner parts are covered with studs in the shape of a truncated pyramid. The cells are cooled by the circulation of air between the studs. The disadvantage of the studs is that they increase the length of the battery.The presence of air circulation channels is also undesirable, as they can contribute to the propagation of thermal runaway. Furthermore, the battery casing must have openings to allow air to enter and exit. Finally, the contact area between a cell and the barrier is relatively small, limited to the truncated upper surface of the studs. As with the previous document, this cell swelling compensation system reduces heat transfer within the battery when used under nominal operating conditions. However, it is not designed to prevent the propagation of thermal runaway from one cell to a neighboring cell.

[0010] There therefore remains a need for a system to compensate for the swelling of the elements which also prevents the propagation of thermal runaway between the elements. Summary of the invention

[0011] To this end, the invention proposes a battery comprising: - at least two electrochemical elements in parallelepiped format, - a first layer of a refractory material resistant to a temperature up to 1200°C disposed in contact with the entirety of a first face which is one of the faces with the largest area of ​​one of the electrochemical elements, said first layer comprising a central region having as its center the center of the first layer and having an area representing 30 to 60% of the area of ​​said first face; - a rigid shim having a hardness greater than or equal to 90 Shore A according to ASTM D 2240-15(2021), disposed between said first layer and the second electrochemical element, the rigid shim being located outside the central region of said first layer.

[0012] On the one hand, the placement of a layer of refractory material in contact with the entire face of the largest area of ​​one of the elements makes it possible to create a thermal barrier preventing the propagation of a thermal runaway from this element to the neighboring elements.

[0013] On the other hand, placing a rigid wedge outside the central region of the refractory material layer ensures that this central region is not compressed by the elements during their swelling and therefore retains its function as a thermal barrier.

[0014] According to one embodiment, the battery comprises a second layer of a refractory material resistant to a temperature up to 1200°C, this second layer being disposed between the rigid wedge and the second electrochemical element and being in contact with the whole of a second face which is one of the faces with the largest area of ​​the second electrochemical element, said second layer comprising a central region having as its center the center of said second layer and having an area representing 30 to 60% of Faire of said second face.

[0015] According to one embodiment, the refractory material of the first layer and / or the second layer is compressible so that its thickness can be reduced by at least 50% or at least 70% or at least 80% under the effect of compression exerted by the two electrochemical elements.

[0016] According to one embodiment, the refractory material of the first layer and / or the second layer is compressible so that its thickness can be reduced up to 95% under the effect of compression exerted by the two electrochemical elements.

[0017] According to one embodiment, the refractory material of the first layer and / or the second layer is a sheet comprising ceramic fibers.

[0018] According to one embodiment, the refractory material of the first layer and / or of the second layer has a thermal conductivity at 20°C less than or equal to 0.5 W / (mK).

[0019] According to one embodiment, the rigid wedge is made of a plastic material that is chemically stable up to a temperature of 200°C.

[0020] According to one embodiment, the rigid wedge is made of a material selected from the group consisting of polytetrafluoroethylene (PTFE), polyimide (PI) and polyepoxide (PE).

[0021] According to one embodiment, the rigid wedge comprises four uprights forming a first rectangular frame.

[0022] According to one embodiment, the rigid wedge further comprises four other uprights forming a second rectangular frame of greater height and width than the first rectangular frame.

[0023] According to one embodiment, - the first layer and / or the second layer has a height and a width, and - the height and width of the second frame correspond to the height and width of the first layer and / or the second layer.

[0024] According to one embodiment, the first and second rectangular frames are joined together by means of at least two connecting elements.

[0025] According to one embodiment, the battery comprises six connecting elements, two connecting elements each linking a horizontal upright of the first frame to a horizontal upright of the second frame, four connecting elements each linking a corner of the first frame to a corner of the second frame.

[0026] According to one embodiment, the two ends of the connecting elements have reinforcements to stiffen the connection of the first frame to the second frame.

[0027] According to one embodiment, the thickness of a post ranges from 0.5 to 1.5 mm, preferably from 0.7 to 1 mm.

[0028] According to one embodiment, an assembly means makes it possible to secure the first layer of refractory material with the rigid wedge.

[0029] According to one embodiment, an assembly means makes it possible to secure the first layer of refractory material with the rigid wedge and with the second layer of refractory material.

[0030] The invention also relates to a method for assembling the battery as described above. This method comprises the steps of: a) provision of a first electrochemical element in parallelepiped format, (b) application of a first layer of a refractory material resistant to temperatures up to 1200°C in contact with the entirety of a first face which is one of the faces with the largest surface area of ​​one of the electrochemical elements, said first layer comprising a central region having as its center the center of the first layer and an area representing 30 to 60% of the first face; c) placement of a rigid shim having a hardness greater than or equal to 90 Shore A according to ASTM D 2240-15(2021), against the first layer, the rigid shim being located outside the central region of said first layer; d) adherence against the rigid wedge of a second face which is one of the faces with the largest area of ​​the second electrochemical element in parallelepiped format.

[0031] According to one embodiment, the process comprises between step c) and step d) the placement of a second layer of a refractory material resistant to a temperature up to 1200°C, said second layer comprising a central region having as its center the center of the second layer and an area representing 30 to 60% of the area of ​​the second face, the second layer being in contact with the entirety of the second face.

[0032] According to one embodiment, the method comprises, after step d), a step of compressing said at least two electrochemical elements by means of a belt, armature, strap, or frame around the elements. Brief description of the drawings

[0033] Embodiments of the invention are described below in more detail with reference to the accompanying drawings.

[0034] [Fig. 1] is a schematic cross-sectional view of a battery comprising two electrochemical elements separated by a layer of refractory material and a rigid wedge.

[0035] [Fig.2] is a schematic cross-sectional view of a battery comprising two electrochemical elements separated by two layers of refractory material and a rigid wedge, the rigid wedge being intercalated between the two layers of refractory material.

[0036] [Fig.3] shows a top view of an assembly consisting of a layer of refractory material on which a rigid wedge is placed. Description of the embodiments of the invention

[0037] The container for the elements is parallelepiped in shape. It has six faces: a top face, a bottom face, and four lateral faces. The bottom face is the one in contact with the support on which the element rests. Two of the six faces are parallel and are the faces with the largest surface area. The two faces with the largest surface area are generally those most prone to swelling. Preferably, the two faces with the largest surface area are oriented perpendicular to the support on which the element rests.

[0038] For the two faces of the container with the largest surface area, a central region and a peripheral region are defined. The central region undergoes greater swelling than the peripheral region. The central region has its center at the center of the The face in question extends over an area representing 30 to 60% or 40 to 50% of the container face area. The peripheral region is the region extending beyond the central region.

[0039] The first layer of refractory material is placed in contact with one of the container faces with the largest surface area. Generally, the height and width of the first layer of refractory material correspond to the height and width of the container face with the largest surface area. This first layer of refractory material is defined as having a central region and a peripheral region. The central region is centered on the center of the first layer and extends over an area representing 30 to 60% or 40 to 50% of the surface area of ​​the container face with the largest surface area. It is important that the central region of the refractory material layer not be crushed by the compression of the elements. To this end, the rigid spacer is placed outside the central region of the refractory material layer. The rigid spacer ensures that there is no compression of the refractory material layer in the central region.It ensures that the thickness of the refractory material layer is at least equal to a given thickness, which is equal to the thickness of the rigid wedge.

[0040] It is possible to use one, two, or even more layers of refractory material between the elements. The refractory material can be highly compressible, meaning that under compression, its thickness can be reduced by at least 50%, 70%, or 80%. Its thickness can be reduced by up to approximately 95%.

[0041] The refractory material withstands temperatures up to at least 1200 °C. It can be a sheet comprising ceramic fibers, i.e., artificial vitreous (silicate) fibers with random orientation and whose weight percentage of alkali oxides and alkaline earth oxides: [Na₂O] + [K₂O] + [CaO] + [MgO] + [BaO] is less than 18%. These fibers are made from silica / alumina mixtures or from kaolinite. Other oxides such as zirconia, boron oxides, or titanium oxides can be added. The ceramic fibers are highly compressible. They therefore act like a spring. The thickness of the sheet comprising ceramic fibers thus adapts to the distance between two elements. The sheet comprising ceramic fibers compensates for slight variations in the dimensions of the elements that might occur during their manufacture. This allows the use of a single size of battery pack.

[0042] In addition to its ability to withstand high temperatures, the refractory material may also have the property of being a good thermal insulator and of preventing the heat generated by an abnormally functioning element from propagating to neighboring elements. The refractory material may have a thermal conductivity at 20°C in- less than 0.5 W / (mK), preferably ranging from 0.02 to 0.2 W / (mK).

[0043] The rigid spacer is made of a material with a hardness greater than or equal to 90 Shore A according to ASTM D 2240-15(2021). Its rigidity allows for maintaining a constant gap between two adjacent elements. Without a rigid spacer, the swelling of two adjacent elements would lead to the almost total compression of the refractory material layer along its entire height. The thickness of the refractory material layer could, in fact, represent only 5% of its thickness before compression. At such a low thickness, the refractory material layer would practically no longer fulfill its function as a thermal barrier. Thanks to the invention, the refractory material layer is reduced only at the location of the rigid spacer, that is to say, only in the peripheral region. Since the refractory material layer is in contact with virtually the entire height of the element, it is possible to obtain a very effective thermal barrier.

[0044] The material constituting the rigid spacer preferably withstands a temperature of at least 200°C. Preferably, it is a non-conductive material (such as plastic). Even more preferably, it is polytetrafluoroethylene (PTFE), polyimide (PI), or polyepoxide (PE). The thickness of the rigid spacer is not limited. It is chosen by an operator according to the desired spacing between the elements and the minimum desired thickness of the refractory material layer. It can range from 0.5 to 1.5 mm, preferably from 0.7 to 1 mm. The use of a rigid spacer keeps the refractory material uncompressed and maintains a constant spacing between two elements. Thus, the length of the battery does not vary during its operation.The invention therefore makes it possible to meet the dual requirement of having, on the one hand, a battery that maintains a constant length during its operation, and on the other hand, one that prevents the propagation of thermal runaway between the battery cells.

[0045] Figure 1 schematically represents a first embodiment in which a single layer of refractory material is used. It shows a battery (1) comprising two parallelepiped-shaped electrochemical elements (2-1, 2-2). The container for these elements has an upper face with the positive and negative terminals and a lower face opposite the upper face in contact with a support. The elements are electrically connected by a connecting piece (15). A layer of refractory material (3-1) is arranged between the elements. In this example, the height of the refractory material layer is the same as the height of the elements. One face of the refractory material layer is in contact with one of the largest faces (4-1) of one of the elements (2-1). The contact extends over the entire height of the refractory material layer.The opposite face of the refractory material layer is not completely in contact with one of the faces with the largest area. large (4-2) of the neighboring element (2-2). Indeed, the presence of the rigid spacer (5) of thickness "e" prevents the opposite face of the refractory material layer (3-1) from being completely in contact with the face with the largest area (4-2) of the neighboring element (2-2). The central and peripheral regions are represented schematically by the letters C and P, respectively. The two boundaries L1 and L2 between the central region C and the peripheral region P of the containers of the two elements coincide with the boundaries between the central and peripheral regions of the refractory material layer. Note that the rigid spacer is positioned outside the central region. The refractory material layer is therefore compressed only in its peripheral region, which is the least prone to swelling. The refractory material layer in its central region is not deformed.

[0046] Figure 2 schematically represents a second embodiment in which two layers (3-1, 3-2) of refractory material are arranged between two elements (2-1, 2-2). This second embodiment is preferable to the first because the two faces (4-1, 4-2) of the two opposing elements are both completely in contact with a layer of refractory material. The thermal barrier effect is therefore improved.

[0047] The rigid wedge preferably has the form of a frame comprising two vertical uprights of height H1 and two horizontal uprights of length L1. The height H1 and the length L1 are determined so that the area of ​​the frame is greater than the area of ​​the central region of the layer of refractory material and therefore that once in place between the elements, the rigid wedge is located outside the central region of the layer of refractory material.

[0048] For easy placement of the wedge between the elements during battery manufacturing, the frame can be made integral with a second frame of dimensions H2 and L2 greater than H1 and LL. Preferably, the second frame, the layer(s) of refractory material and the face of the container in contact with a layer of refractory material have the same height and width.

[0049] The first frame is joined to the second frame by means of connecting elements. When the second frame is placed between two electrochemical elements, it is aligned with the edge of the electrochemical elements. The first frame is automatically and correctly positioned outside the central region of the refractory material layer.

[0050] The connecting elements linking the first frame to the second frame can be six in number, two connecting elements each linking a horizontal upright of the first frame to a horizontal upright of the second frame, four connecting elements each linking a corner of the first frame to a corner of the second frame.

[0051] The junction area between a connecting element and an upright of the first or second frame can be reinforced by locally widening the junction area. This The enlargement can have a circular or rectangular shape.

[0052] The assembly formed by the first frame, the second frame, the connecting elements and possibly the reinforcements can be manufactured by molding a plastic part. This results in a single part that is easily handled and easy to position.

[0053] The rigid wedge can be integrated into a layer of refractory material. It can also be sandwiched between two layers of refractory material. In both cases, this allows only one part to be handled during the assembly of the components.

[0054] Figure 3 is a top view of an assembly consisting of a layer of refractory material (3-1) on which a rigid wedge is placed. The rigid wedge comprises a first frame with two horizontal uprights (6-1, 6-3) of length L1 and two vertical uprights (6-2, 6-4) of height HL. This first frame is inscribed within a second, larger frame with two horizontal uprights (6-5, 6-7) of length L2 and two vertical uprights (6-6, 6-8) of height H2. The dimensions of the second frame correspond to the dimensions of the layer of refractory material, which can itself be cut to the dimensions of the face of the element with which it is in contact. The dimensions H1 and L1 of the first frame are calculated so that it lies outside the central region of the layer of refractory material. The first frame is joined to the second frame using connecting elements.Two connecting elements (8-1, 8-2) each link a horizontal stile of the first frame to a horizontal stile of the second frame. Four connecting elements (9-1, 9-2, 9-3, 9-4) each link a corner of the first frame to a corner of the second frame. The ends of the connecting elements are provided with reinforcements (10) which consist of a widening of the junction area between the stiles of the first or second frame and the connecting elements.

[0055] A method for assembling a battery comprising at least two electrochemical elements includes the steps of: a) provision of a first electrochemical element in parallelepiped format, b) placement of a first layer of a refractory material resistant to a temperature of up to 1200°C in contact with the whole of a first face which is one of the faces with the largest area of ​​one of the electrochemical elements, said first layer comprising a central region having as its centre the centre of the first layer and an area representing 30 to 60% of the first face; c) placement of a rigid wedge having a hardness greater than or equal to 90 Shore A according to ASTM D 2240-15(2021) against the first layer, the rigid wedge being located outside the central region of said first layer; d) adherence against the rigid wedge of a second face which is one of the faces of large area of ​​the second electrochemical element in parallelepiped format.

[0056] Preferably, before attaching the second electrochemical element, a second layer of refractory material resistant to a temperature of up to 1200°C is attached to the rigid wedge, said second layer having a central region having as its center the center of the second layer and an area representing 30 to 60% of the area of ​​the second face in contact with the entire second face of the second electrochemical element.

[0057] To facilitate the placement of the rigid wedge, a rigid wedge consisting of two frames of different dimensions joined together can be used, the larger frame having a height and width identical to those of the refractory material layer and to those of the container face of the element, as shown in [Fig. 3]. This allows the rigid wedge to be positioned correctly between the two elements automatically.

[0058] Finally, the rigid wedge can be attached to the layer(s) of refractory material to form an assembly placed between the two elements in a single step. One face of the layer(s) of refractory material may have an adhesive. One face of the rigid wedge may also have an adhesive. Another method consists of providing a clamp or clip on the outer frame of the rigid wedge that holds the layer(s) of refractory material in place.

Claims

Demands

1. Battery (1) comprising: - at least two parallelepiped-shaped electrochemical elements (2-1, 2-2), - a first layer (3-1) of a refractory material resistant to a temperature up to 1200°C disposed in contact with the entirety of a first face which is one of the faces (4) with the largest area of ​​one (2-1) of the electrochemical elements, said first layer having a central region (C) having as its center the center of the first layer and having an area representing from 30 to 60% of the area of ​​said first face; - a rigid spacer (5) having a hardness greater than or equal to 90 Shore A according to ASTM D 2240-15(2021), disposed between said first layer and the second electrochemical element (2-2), the rigid spacer being located outside the central region of said first layer.

2. Battery (1) according to claim 1, comprising a second layer (3-2) of a refractory material resistant to a temperature up to 1200°C, this second layer being disposed between the rigid wedge (5) and the second electrochemical element (2-2) and being in contact with the whole of a second face which is one of the faces with the largest area of ​​the second electrochemical element, said second layer comprising a central region (C) having as its center the center of said second layer and having an area representing from 30 to 60% of Faire of said second face.

3. Battery (1) according to any one of claims 1 and 2, wherein the refractory material of the first layer (3-1) and / or the second layer (3-2) is compressible so that its thickness can be reduced by at least 50% or at least 70% or at least 80% under the effect of compression exerted by the two electrochemical elements.

4. Battery (1) according to any one of claims 1 to 3, wherein the refractory material of the first layer (3-1) and / or the second layer (3-2) is compressible so that its thickness can be reduced up to 95% under the effect of compression exerted by the two electrochemical elements.

5. Battery (1) according to any one of the preceding claims, wherein the refractory material of the first layer (3-1) and / or the second layer (3-2) is a sheet comprising ceramic fibers.

6. Battery (1) according to any one of the preceding claims, wherein the refractory material of the first layer (3-1) and / or the second layer (3-2) has a thermal conductivity at 20°C less than or equal to 0.5 W / (mK).

7. Battery (1) according to any one of the preceding claims, wherein the rigid wedge (5) is made of a plastic material that is chemically stable up to a temperature of 200°C.

8. Battery (1) according to claim 7, wherein the rigid wedge (5) is made of a material selected from the group consisting of polytetrafluoroethylene (PTFE), polyimide (PI) and polyepoxide (PE).

9. Battery (1) according to any one of the preceding claims, wherein the rigid wedge (5) comprises four uprights (6-1, 6-2, 6-3, 6-4) forming a first rectangular frame.

10. Battery (1) according to claim 9, wherein the rigid wedge (5) further comprises four other uprights (6-5, 6-6, 6-7, 6-8) forming a second rectangular frame of greater height and width than the first rectangular frame.

11. Battery (1) according to claim 10, wherein: - the first layer (3-1) and / or the second layer (3-2) has a height (H) and a width (L), and - the height and width of the second frame correspond to the height and width of the first layer and / or the second layer.

12. Battery (1) according to any one of claims 10 and 11, wherein the first and second rectangular frames are joined together by means of at least two connecting elements (8-1, 8-2).

13. Battery (1) according to claim 12, comprising six connecting elements, two connecting elements (8-1, 8-2) each connecting a horizontal upright of the first frame to a horizontal upright of the second frame, four connecting elements (9-1, 9-2, 9-3, 9-4) each connecting a corner of the first frame to a corner of the second frame.

14. Battery (1) according to any one of claims 12 to 13, wherein both ends of the connecting elements have reinforcements (10) enabling the connection of the first frame to be stiffened to the second frame.

15. Battery (1) according to any one of claims 9 to 14, wherein the thickness (e) of an amount ranges from 0.5 to 1.5 mm, preferably from 0.7 to 1 mm.

16. Battery (1) according to any one of claims 9 to 15, wherein an assembly means allows the first layer to be secured (3-1) of refractory material with the rigid wedge (5).

17. Battery (1) according to any one of claims 2 to 15, wherein an assembly means makes it possible to secure the first layer (3-1) of refractory material with the rigid wedge (5) and with the second layer (3-2) of refractory material.

18. Method of assembling a battery (1) comprising at least two electrochemical elements (2-1, 2-2), said method comprising the steps of: a) making available a first electrochemical element (2-1) of parallelepiped format, b) placing a first layer (3-1) of a refractory material resistant to a temperature up to 1200°C in contact with the entirety of a first face which is one of the faces (4) of largest area of ​​one of the electrochemical elements (2-1), said first layer comprising a central region (C) having as its center the center of the first layer and an area representing from 30 to 60% of the area of ​​the first face; (c) placement of a rigid shim (5) having a hardness greater than or equal to 90 Shore A according to ASTM D 2240-15(2021), against the first layer (3-1), the rigid shim being located outside the central region of said first layer;d) adherence against the rigid wedge of a second face which is one of the faces with the largest area of ​​the second electrochemical element (2-2) of parallelepiped format.;

19. Method according to claim 18 comprising between step c) and step d) the placement of a second layer (3-2) of a refractory material resistant to a temperature up to 1200°C, said second layer comprising a central region (C) having as its center the center of the second layer and an area representing 30 to 60% of the area of ​​the second face (3-2), the second layer being in contact with the entirety of the second face.

20. A method according to any one of claims 18 or 19, comprising after step d), a step of compressing said at least two electrochemical elements (2-1, 2-2) by means of a belt or armature or strap or frame around the elements.

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