Battery

Abstract

The battery (1) comprises a side wall (3) and a bottom wall (4) defining an interior space (7), a hollow vessel (2) having a top part (8) with an outer surface (53), an electrochemical cell (9) inserted into the interior space (7) of the hollow vessel (2), an insert (15) made of conductive material mechanically and electrically connected to the poles of the electrochemical cell (9), a lid (30) arranged to close the hollow vessel (2) at the top part (8), and an overlapping area (50) where the top part (8) of the hollow vessel (2) is located axially above the lid (30) and above the connecting portion (21) of the insert (15) made of conductive material. A weld (42) between at least the connecting portion (21) of the insert (15) made of conductive material and the top part (8) of the hollow vessel (2), the weld (42) being located in the overlapping area (50) on the side facing the outer surface (53) of the top part (8) of the hollow vessel (2).

Description

[Technical field]

[0001] The present invention relates to batteries that can be used in applications where electrical energy needs to be made available. [Background technology]

[0002] A battery, also called a secondary electrochemical cell or rechargeable battery, is a device that converts chemical energy into electrical energy through a reversible oxidation-reduction reaction, and then converts electrical energy back into chemical energy by reversing the oxidation-reduction process.

[0003] The battery includes a hollow container into which is inserted an electrochemical cell formed of an anode, a cathode, and a separator disposed between the anode and cathode. The cathode is electrically connected to the bottom base of the container, and the anode is electrically connected to the top plate of the container.

[0004] In some types of applications, the electrochemical cell inserted into the hollow container is a type of electrochemical cell called a jelly roll or Swiss roll, which includes a sheet of insulating material in which anode material, separator material, and cathode material are arranged in succession in thin layers or sheets. The laminate thus constructed is rolled onto itself and inserted into the container. The cathode material is placed at the bottom of the hollow container and makes electrical contact with an electrode electrically insulated from the container itself. The anode material is in electrical contact with a lid placed at the end of the container, forming a further electrode.

[0005] Examples of such applications include lithium ion, nickel cadmium and nickel metal hydride batteries.

[0006] In Applicant's experience, the sidewall of the hollow vessel must be in electrical contact with the anode material.

[0007] In the applicant's experience, electrical contact between the anode material and the side wall of the hollow vessel is achieved by welding an insert of conductive material (e.g. copper) to the anode material before inserting the electrochemical cell into the hollow vessel. After the electrochemical cell is inserted into the hollow vessel, the insert of conductive material is welded to the inner surface of the side wall inside the hollow of the hollow vessel, and the hollow vessel is closed with a lid. The lid in contact with the vessel (and the vessel in contact with the insert of conductive material) assumes the same electrical potential as the side wall of the hollow vessel.

[0008] The applicant has realized that in the battery briefly described above, it is not always appropriate to provide a weld between the insert made of conductive material and the inner surface of the side wall of the hollow container in the interior space of the hollow container.

[0009] Indeed, the applicant has determined that if weld residue or spalled weld filler material reaches the electrochemical cell, the correct operation of the battery may be compromised.

[0010] Applicants have realized that there is room for improvement in batteries.

[0011] The applicant has realised that in practice, after the electrochemical cell has been placed inside the hollow vessel, it is necessary to close the free rim of the hollow vessel with a lid.

[0012] Applicant has realised that by extending the insert of conductive material to reach the union region between the free rim of the hollow container and the lid, an axial overlap region can be created between the insert of conductive material, the free rim of the hollow container and the lid, in which the free rim of the hollow container is axially outermost.

[0013] Thus, the applicant has discovered that by locating a weld in this overlapping area, with a lid already installed to cover the hollow container, it is possible to join at least a portion of the free rim of the hollow container and the insert of conductive material and ensure electrical continuity between the insert of conductive material and the hollow container. The applicant has discovered that by locating this weld in the overlapping area on the side of the free rim of the hollow container facing the outer surface, the weld (or welds) is substantially placed on the outer surface of the already assembled battery, preventing the risk of weld residues reaching the electrochemical cell.

[0014] Thus, the present invention relates to a battery.

[0015] Preferably, the hollow vessel comprises a side wall and a bottom wall defining an interior space, the top being axially opposite the bottom wall and including an exterior surface.

[0016] Preferably, there is provided an electrochemical cell inserted into the interior space of the hollow vessel.

[0017] Preferably, an insert of conductive material is provided which is mechanically and electrically connected to the poles of the electrochemical cell.

[0018] Preferably, a lid is provided arranged to close the top of the hollow vessel.

[0019] Preferably, an overlapping region is provided in which the upper part of the hollow container is located on the axis of the lid and above the connection part of the insert made of conductive material.

[0020] Preferably, a weld is provided between the connecting portion of the insert made of conductive material and the top of the hollow vessel.

[0021] Preferably, the weld is located in the overlapping area on the exterior facing side of the upper portion of the hollow vessel.

[0022] Applicant has determined that welding at least the connecting portion of the insert made of conductive material to the top of the hollow vessel effectively provides permanent electrical contact between the hollow vessel and the insert made of conductive material (which is in electrical contact with the poles of the electrochemical cell).

[0023] The applicant has also determined that by locating the weld on the side of the upper part of the hollow container facing the outer surface, a weld can be performed in which the area of ​​the contact portion of the insert made of conductive material is fused to at least the upper part of the hollow container, either directly or through the upper part of the hollow container.

[0024] Applicants believe that this will eliminate the need to weld an insert of conductive material within the hollow vessel volume to the inside surface of the hollow vessel.

[0025] The applicant also believes that by avoiding welding an insert of conductive material to the inner surface of the hollow vessel within the volume of the hollow vessel, it is possible to prevent welding residues from accidentally reaching the electrochemical cells and impairing the correct operation of the battery.

[0026] The terms "axial" and "radial" are used to refer to directions contained in planes parallel and perpendicular, respectively, to the cell's main axis of deployment.

[0027] The terms "radially innermost" and "radially outermost" refer to positions closer to and further from the main axis of deployment of the cell, respectively.

[0028] The terms "axially outermost" or "axially upper" refer to the location furthest from a plane perpendicular to the cell's main axis of deployment and passing through the cell's center of gravity.

[0029] The terms "axially innermost" or "axially lower" refer to the location nearest to a plane perpendicular to the cell's main axis of deployment and passing through the cell's center of gravity.

[0030] In this specification and the following claims, the term "conductive material" means a material that can carry an electric current and has a resistance of 1×104 This refers to materials with electrical conductivity of 1×10 at 20°C or more. 5 Siemens / meter or more, preferably 1×10 at 20°C 6 It refers to a material that has an electrical conductivity of Siemens / meter or greater.

[0031] As used in this specification and the following claims, the terms "mechanically couple" or "mechanically coupled" mean joining two or more parts or components together to form an assembly in which the parts or components are mechanically constrained.

[0032] As used in this specification and the claims that follow, the term "direct electrical contact" means that there is electrical continuity between two parts or components without any intervening electrically conductive means between them.

[0033] As used in this specification and the claims that follow, the term "direct electrical contact" means that there is electrical continuity between two parts or components without any intervening electrically conductive means between them.

[0034] In this specification and in the claims that follow, the term "electrical contact" means electrical continuity between two parts or components. The electrical contact between the two parts or components may be direct or may have an intermediate electrical conducting means between the two parts or components.

[0035] As used herein and in the claims that follow, the terms "plastic deformation" or "plastically deformed" refer to deformation that does not disappear when the forces that caused such deformation disappear.

[0036] In this specification and in the following claims, the term "cold plastic deformation" refers to a treatment of a metal carried out at a treatment temperature below 40% of the melting point of the metal being treated, preferably below 30% of the melting point of the metal being treated. For example, for a metallic material with a melting point of 1000°C, cold deformation occurs at a temperature below 400°C, preferably below 300°C.

[0037] The present invention may exhibit at least one of the preferred characteristics described below. In the battery of the present invention, these characteristics may be present individually or in combination with each other, unless otherwise specified.

[0038] Preferably, the weld joins the connecting portion of the insert made of conductive material, the top of the hollow vessel, and the lid together.

[0039] Preferably, no welds are provided between the insert of electrically conductive material and the inner wall of the hollow vessel at an axial location between the bottom wall of the hollow vessel and the periphery of the lid.

[0040] Preferably, in said overlapping region, the connecting portion of the insert made of electrically conductive material is axially interposed between and in contact with the top of the hollow container and the lid.

[0041] Preferably, the connecting portion of the insert made of electrically conductive material is in direct electrical contact with at least the upper portion of the hollow vessel in the overlapping region.

[0042] Preferably, in said overlapping region, the top of the hollow vessel does not axially overlap the free end of the connecting portion of the insert made of electrically conductive material.

[0043] Preferably, the connecting portion of the insert of electrically conductive material includes a radially inner free end which is not axially overhung by the upper portion of the hollow vessel.

[0044] Preferably, the welding is performed by a laser welder.

[0045] Preferably, the weld is an annular weld across the outer surface of the upper portion of the hollow vessel, reaching at least the connecting portion of the insert of electrically conductive material.

[0046] Preferably, in this case, the free end of the connecting part of the insert made of electrically conductive material which does not overhang axially above the top of the hollow vessel faces directly to the external environment.

[0047] Preferably, the annular weld passes across the outer surface of the top of the hollow vessel, across the connecting portion of the insert of electrically conductive material, and onto the lid.

[0048] Preferably, said annular weld is obtained by welding with a welding machine on the side of the upper part of the hollow vessel facing the outer surface.

[0049] Preferably, said annular weld is obtained by directing a beam emitted by a laser welder onto the outer surface of the top of the hollow vessel.

[0050] Preferably, the annular weld has a radial thickness of between 30 and 300 μm, preferably between 30 and 200 μm, more preferably between 30 and 100 μm, for example about 50 μm.

[0051] Preferably, the connecting portion of the insert made of conductive material, the top of the hollow vessel and the lid are welded simultaneously.

[0052] Alternatively, the weld is a spot weld across the outer surface of the upper portion of the hollow vessel at least as far as the connecting portion of the insert of electrically conductive material.

[0053] Preferably, in this case, the free end of the connecting part of the insert made of electrically conductive material does not project axially above the top of the hollow vessel but faces the external environment.

[0054] Preferably, the spot weld passes across the outer surface of the top of the hollow container, across the connecting portion of the insert of conductive material, and onto the lid.

[0055] Preferably, said spot weld is obtained by welding with a welding machine on the side of the upper part of the hollow vessel facing the outer surface.

[0056] Preferably, the spot weld is obtained by irradiating a beam from a laser welder onto a spot on the outer surface of the upper part of the hollow container.

[0057] Preferably, the spot welds include circumferentially disposed weld spots.

[0058] Preferably, the diameter of each of said weld spots is between 30 and 300 μm, preferably between 30 and 200 μm, more preferably between 30 and 100 μm, for example about 50 μm.

[0059] Preferably, the connecting portion of the insert made of conductive material, the top of the hollow vessel and the lid are welded simultaneously.

[0060] Alternatively, said weld is located at the free end of the connecting portion of the insert made of electrically conductive material.

[0061] Preferably, in this case, the free end of the connecting portion of the insert made of electrically conductive material is melted so that it does not overhang axially above the top of the hollow vessel, but reaches radially above the top of the hollow vessel.

[0062] Preferably, the free end of the insert of conductive material is fused onto the lid.

[0063] Preferably, the outer surface of the top of the hollow vessel is provided with a recess at the weld.

[0064] Preferably, the recess is substantially annular.

[0065] Preferably, said recess has a radial extension of 0.3 mm to 3 mm, preferably 0.5 mm to 2 mm, preferably 0.5 mm to 1.5 mm, for example 1 mm.

[0066] Preferably, said recess has an axial extension of between 0.1 mm and 0.5 mm, preferably between 0.1 mm and 0.4 mm, for example 0.3 mm.

[0067] Preferably, the annular weld is located inside the recess.

[0068] Preferably, the spot welds are disposed inside the recesses.

[0069] Preferably, the thickness of the upper part of the hollow vessel is 0.1 mm to 0.8 mm, preferably 0.2 mm to 0.6 mm.

[0070] Preferably, the thickness of the upper portion of the hollow vessel is constant throughout the hollow vessel.

[0071] Preferably, the thickness of the side wall of the hollow vessel is equal to the thickness of the top of said hollow vessel.

[0072] Preferably, the weld seals the lid and the top of the hollow container, isolating the interior space of the hollow container from the outside environment.

[0073] Preferably, the insert of electrically conductive material is in electrical contact with at least the top of the hollow vessel.

[0074] Preferably, the lid is in electrical contact with at least the top of the hollow vessel.

[0075] Preferably, said pole of said electrochemical cell is the anode of said electrochemical cell.

[0076] Preferably, the electrochemical cell is constructed by winding on itself a multi-layer body including a first layer of an anode material constituting the anode, a second layer of a cathode material constituting the cathode, and a third separator layer separating the anode material and the cathode material.

[0077] Preferably, the first layer of the electrochemical cell is axially offset relative to the second layer of the electrochemical cell, the first layer having an axial end facing the lid that is closer to the lid than the axial end of the second layer facing the lid.

[0078] Preferably, the axial end of the first layer of the electrochemical cell facing the lid is plastically deformed to form an anodic surface.

[0079] Preferably, the insert of conductive material is shaped so that the bottom surface of the cup provides the contact surface and the side walls of the cup provide the connection.

[0080] Preferably, the contact portion and the connection portion are integrally formed.

[0081] Preferably, the insert of conductive material is made of copper.

[0082] Preferably, the contact portion of the insert made of conductive material is welded to the anode of said electrochemical cell.

[0083] Preferably, the hollow vessel is made of steel.

[0084] Preferably the lid is made of steel.

[0085] Preferably, the lid and the hollow container are formed from the same material.

[0086] Preferably, the lid is disc-shaped.

[0087] Preferably, at least the connecting portion of the insert made of conductive material and the upper portion of the hollow container are plastically deformed to define a stable mechanical bond between the side wall of the hollow container, the lid and the insert made of conductive material.

[0088] Preferably, the connecting portion of the insert made of conductive material and the upper portion of the hollow vessel are plastically deformed so that the shape of the connecting portion of the insert made of conductive material is substantially equal to the shape of the upper portion of the hollow vessel.

[0089] Preferably, the upper portion of the hollow vessel is bent to form a curved portion.

[0090] Preferably, the curved portion has a recess facing radially inwards.

[0091] Preferably, the curved portion extends circumferentially along the entire upper portion of the hollow vessel forming the groove.

[0092] Preferably, the connecting portion of the insert of conductive material is bent to form a curved portion.

[0093] Preferably, the curved portion has a recess facing radially inwards.

[0094] Preferably, said curved portion extends circumferentially along the entire connecting portion of the insert made of electrically conductive material forming the groove.

[0095] Preferably, the curved portion defined by the connecting portion of the insert of conductive material is inserted into the curved portion of the upper portion of the hollow vessel.

[0096] Preferably, the periphery of the lid is inserted into a curved portion of an insert of conductive material.

[0097] Further features and advantages of the present invention will become apparent from the following detailed description of preferred embodiments of the invention, given as illustrative and non-limiting examples, with reference to the accompanying drawings, in which: [Brief description of the drawings]

[0098] [Figure 1] FIG. 1 is a schematic cross-sectional view of a battery of the present invention. [Diagram 2] FIG. 2 is an enlarged view of a detail of the cell of FIG. 1 according to the first embodiment. [Diagram 3] FIG. 3 is an enlarged view of a detail of the cell of FIG. 1 according to a second embodiment. [Figure 4] FIG. 4 is a top view of a detail of FIG. [Diagram 5] FIG. 5 is a top view of a detail of FIG. [Figure 6] FIG. 6 is a top view of the same detail of FIG. 3 in yet another embodiment. [Figure 7] FIG. 7 is a top view of the same detail of FIG. 4 in yet another embodiment. [Figure 8] FIG. 8 is an enlarged view of a detail of the cell of FIG. 1 according to a third embodiment. [Figure 9] FIG. 9 is a top view of a detail of FIG. [Figure 10] FIG. 10 is a schematic side view of components of the battery of FIG. [Figure 11] FIG. 11 is a schematic top view of components of the battery of FIG. [Figure 12] FIG. 12 is a perspective schematic view of further components of the battery of FIG. [Figure 13] FIG. 13 is a schematic diagram of some of the battery assembly steps of FIG. [Figure 14] FIG. 14 is a schematic diagram of some of the battery assembly steps of FIG. [Figure 15] FIG. 15 is an enlarged view of a detail of the battery of FIG. 1 according to yet another embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0099] The representation in the attached figures need not necessarily be understood to scale, nor necessarily to respect the proportions between the parts, in which identical or similar elements of different embodiments are indicated with the same reference numbers.

[0100] Batteries according to the present invention are generally designated by the reference numeral 1.

[0101] A main development axis X is defined for the battery 1. An axial direction parallel to the main development axis X, a radial direction included in a plane perpendicular to the main development axis X and passing through the main development axis X, and a circumferential direction disposed around the main development axis X and included in a plane perpendicular to the main development axis X are defined.

[0102] For ease of explanation, reference will be made explicitly to a battery 1 having a substantially cylindrical shape, with the main deployment axis X substantially coinciding with the axis of symmetry of the battery 1 .

[0103] However, the battery 1 may also have a shape different from that of a cylinder, for example a cuboid with a rectangular base.

[0104] Battery 1 includes a hollow container 2, a lid 30, an electrochemical cell 9, and an insert 15 made of a conductive material.

[0105] The hollow vessel 2 includes a side wall 3 and a bottom wall 4. The side wall 3 and the bottom wall 4 are formed from a single steel plate. The bottom wall 4 and the side wall 3 define an internal space 7 of the hollow vessel 2. The bottom wall 4 and the side wall 3 preferably have the same thickness. The thickness of the side wall 3 and the bottom wall 4 is preferably 0.2 mm or more and 0.6 mm or less, for example, 0.3 mm.

[0106] An electrode 5 is provided on the bottom wall 4 of the hollow vessel 2 and is electrically insulated from the bottom wall 4. The electrode 5 is disposed in the center of the bottom wall 4.

[0107] When the battery 1 is in an unassembled state, the hollow vessel 2 has an opening 6 opposite the bottom wall 4. The hollow vessel 2 includes a top portion 8 that faces the bottom wall 4 along an axial direction. The top portion 8 extends circumferentially around the opening 6.

[0108] In the unassembled state of the battery 1, the top part 8 comprises a straight section 10 (axially) which creates an annular extension of the side wall 3 of the hollow vessel 2 (Figure 13). This straight section 10 is formed integrally with the side wall 3 of the hollow vessel 2. Connected to the straight section 10 is a curved section 11 which widens in the circumferential direction and forms a radial extension of the top part 8. From the curved section 11 a further straight section 12 widens (axially) which in turn widens in the circumferential direction to form a further annular section. The top part 8 ends in a free end 13 which is also the free end of the further straight section 12.

[0109] An electrochemical cell 9, best shown in FIG. 12, includes an anode and a cathode.

[0110] The electrochemical cell 9 is of the jelly roll or Swiss roll type and includes a multi-layer body 14 wound on itself. The multi-layer body 14 includes a first layer 16 formed of an anode material that constitutes the anode of the electrochemical cell 9, and a second layer 17 formed of a cathode material that constitutes the cathode of the electrochemical cell 9. The multi-layer body 14 further includes a third separation layer (or more layers) 18 that separates the first layer 16 and the second layer 17. One skilled in the art can appropriately select the materials of the first layer 16, second layer 17, and third layer 18 to provide the electrochemical cell 9 with the desired electrical performance.

[0111] In a preferred embodiment, the first layer 16 is axially offset from the second layer 17 such that it emerges axially from the laminate 14 wound on itself. The portion of the first layer 16 which protrudes axially from the laminate 14 is plastically deformed such that the free end of the first layer 16 is bent to form an anodic surface 19. This anodic surface 19 is irregular and discontinuous and serves to increase the contact surface of the first layer 16 at the axial end of the electrochemical cell 9.

[0112] The conductive insert 15 is preferably made of copper. As best shown in Figures 10 and 11 (when the conductive insert 15 is not yet assembled into the battery 1), the conductive insert 15 has a shape along a cross section perpendicular to the axial direction that substantially matches the shape of the bottom wall 4 of the hollow vessel 2. In this embodiment, the conductive insert 15 has a shape along a cross section perpendicular to the axial direction that is substantially circular.

[0113] The insert 15 of conductive material includes a substantially planar contact portion 20. The insert 15 of conductive material further includes a connecting portion 21. The connecting portion 21 projects axially from a radial end of the contact portion 20 and extends axially away from the contact portion 20.

[0114] The contact portion 20 is provided with a number of fins 22. Each fin 22 is defined by a through notch 23 passing axially through the contact portion 20. Each through notch 23 follows a curved locus consisting of two side portions 24 and a central portion 25 (FIG. 11). From the central region of the contact portion 20 to the peripheral region of the contact portion 20, the side portions 24 extend along respective radial directions. The central portion 25 connects the two side portions 24 and extends substantially in the circumferential direction. As shown diagrammatically in FIG. 11, each fin 22 is substantially petal-shaped and can be raised in the axial direction by rotating about a virtual hinge axis that joins the free ends of the two side portions 24 of the notch 23. The fins 22 are preferably between 2 and 8 or more. For example, the fin 18 has four.

[0115] Figure 10 shows a side view of the insert 15 (unassembled) made of electrically conductive material. The connection part 17 comprises a straight section 26 (axially) which widens in the circumferential direction to form an annular section. The straight section 26 is directly connected to the contact part 20. Connected to the straight section 26 is a curved section 27 which projects radially outwards and widens in the circumferential direction to form a radially enlarged part of the upper part 17. From the curved section 27 a further straight section 28 widens (axially) which widens in the circumferential direction to form a further annular section. The connection part 17 ends in a free end 29 which is also the free end of the further straight section 28.

[0116] The lid 30 is made of steel. The lid 30 has a cross-sectional shape perpendicular to the axial direction that substantially corresponds to the shape of the bottom wall 4 of the hollow vessel 2. In the illustrated embodiment, the cross-sectional shape perpendicular to the axial direction of the lid 30 is substantially circular.

[0117] The lid may include one or more reinforcing ribs. The lid 30 includes a peripheral portion 31 radially surrounding a central portion 30a.

[0118] When the battery 1 is in an unassembled state, the peripheral portion 31 includes a radially extending straight portion 32 (FIG. 14). The peripheral portion 31 terminates in a free end 33, which is also a free end of the straight portion 32.

[0119] In the assembled state of the battery 1, the electrochemical cell 9 is inserted into the interior space 7 of the hollow vessel 2 with the cathode facing towards the bottom wall 4. The cathode is electrically connected to the electrode 5. In particular, the second layer 17 of the multi-layer body 14 is electrically connected to the electrode 5 arranged on the bottom wall 4 of the hollow vessel 2.

[0120] The anode is electrically connected to the insert 15 made of conductive material by welding the contact portion 20 to the anode. In particular, the anode face 19 is welded to the fins 22 of the contact portion 20 of the insert 15 made of conductive material.

[0121] In the assembled state of the battery 1, the connecting portion 21 of the insert 15 made of conductive material is interposed between the top portion 8 of the hollow container 2 and the peripheral portion 31 of the lid 30, as shown in FIG.

[0122] The connecting portion 21 of the insert 15 made of electrically conductive material is in direct electrical contact with the top portion 8 of the hollow vessel 2 and the peripheral portion 31 of the lid 30 is in direct electrical contact with the top portion 8 of the hollow vessel 2 .

[0123] The connecting portion 21 of the insert 15 made of electrically conductive material is in direct physical contact with the top portion 8 of the hollow vessel 2 .

[0124] The connecting portion 21 of the insert 15 made of conductive material is in direct physical contact with the periphery 31 of the lid 30 .

[0125] The connecting portion 21 of the insert 15 made of conductive material and the top portion 8 of the hollow container 2 are plastically deformed to create a stable mechanical bond between the side wall 3, the lid 30 and the insert 15 made of conductive material.

[0126] The connecting portion 21 of the insert 15 made of conductive material is in direct electrical and physical contact with the periphery 31 of the lid 30 .

[0127] The upper portion 8 of the hollow vessel 2 is plastically deformed to form a curved portion 40 defined between the curved portion 11 and a further straight portion 12 .

[0128] The connecting portion 21 of the insert 15 made of conductive material is disposed radially inside the upper portion 8 of the hollow vessel 2. As shown in Figures 2, 3 and 8, the connecting portion 21 of the insert 15 made of conductive material is included in a portion of the curved portion 40.

[0129] At this point, the connection portion 21 of the insert 15 made of electrically conductive material is plastically deformed to form a curved portion 41 defined between the curved portion 27 and the further straight portion 28 .

[0130] The curved portion 41 of the connecting portion 21 of the insert 15 made of conductive material is inserted into the curved portion 40 of the top portion 8 of the hollow container 2 and receives the peripheral portion 31 of the lid 30. The peripheral portion 31 of the lid 30 does not bend or deform plastically.

[0131] In the assembled state of the battery, an overlap region 50 is provided in which the upper portion 8 of the hollow container is disposed axially above the lid 30 and above the insert 21 of conductive material 15, as shown in FIGS.

[0132] In said overlapping region 50, the connecting portion 21 of the insert 15 made of conductive material is inserted axially between the top portion 8 of the hollow container and the lid 30.

[0133] In particular, in the overlapping region 50 , an end 51 of the connecting portion 21 of the insert 15 made of electrically conductive material is inserted axially between an end 52 of the top portion 8 of the hollow container 2 and the peripheral portion 31 of the lid 30 .

[0134] The end 51 of the connecting portion 21 of the insert 15 made of conductive material coincides with the further straight portion 28 of the insert 15 made of conductive material.

[0135] The end 52 of the top part 8 of the hollow vessel 2 coincides with the further straight section 12 of the top part 8 of the hollow vessel 2 .

[0136] The upper portion 8 of the hollow vessel 2 does not axially overlap the free end 29 of the connecting portion 21 of the insert 15 made of electrically conductive material.

[0137] 2, 3 and 8, the free end 13 of the upper part 8 of the hollow vessel 2 substantially faces the lid 30 and is radially spaced from the lid 30. The free end 29 of the connecting portion 21 of the insert 15 made of conductive material is axially disposed in the radial space between the free end 13 of the hollow vessel 2 of the upper part 8 and the lid 30.

[0138] In the overlapping area 50, the end 51 of the connecting portion 21 of the insert 15 made of conductive material, the end 52 of the upper portion 8 of the hollow container 2, and the peripheral portion 31 of the lid 30 are parallel to each other and are arranged along their respective radial planes.

[0139] In the overlapping region 50, the top portion 8 of the hollow vessel 2 has an outer surface 53 facing towards the outside environment. This outer surface 53 is the axially outermost surface of the top portion 8 of the hollow vessel 2.

[0140] In all embodiments of the present invention, a weld 42 is provided between at least the connecting portion 21 of the insert 15 made of a conductive material and the upper portion 8 of the hollow vessel 2, which is located in the overlapping area 50 on the side facing the outer surface 53 of the upper portion 8 of the hollow vessel 2.

[0141] A weld 42 preferably connects the connecting portion 21 of the insert 15 made of electrically conductive material, the top portion 8 of the hollow vessel 2 and the peripheral portion 31 of the lid 30 .

[0142] According to the embodiment shown in FIGS. 2, 3, 4 and 5, the weld 42 is an annular weld starting from the outer surface 53 of the top 8 of the hollow vessel 2, across the insert 21 of conductive material 15 and to the periphery 31 of the lid 30.

[0143] The annular weld 42 is a weld that is formed continuously along an essentially circular path on the outer surface 53 of the upper portion 8 of the hollow vessel 2, as shown diagrammatically in Figures 4 and 5 (top view showing a portion of the battery 1).

[0144] In this embodiment, the free end 29 of the connecting portion 21 of the insert 15 made of a conductive material directly faces the external environment. At the free end 29 of the connecting portion 21 of the insert 15 made of a conductive material, the battery components 1 do not overlap in the axial direction.

[0145] The annular weld 42 is free of any filler material and is an interfusion between the connecting portion 21 of the insert 15 made of electrically conductive material, the top portion 8 of the hollow vessel 2 and the peripheral portion 31 of the lid 30 .

[0146] When the battery 1 is assembled, the annular weld 42 is substantially visible and appears as a ring disposed on the outer surface 53 of the top portion 8 of the hollow vessel 2 .

[0147] The annular weld 42 is located radially outward of the radial space between the free end 13 of the top 8 of the hollow vessel 2 and the lid 30 .

[0148] The annular weld 42 is disposed radially outwardly of the free end 29 of the connecting portion 21 of the insert 15 made of electrically conductive material.

[0149] The annular weld 42 has a radial thickness SP, understood as the weld thickness (as shown in Figures 4 and 5), which is less than 1 mm, preferably less than 0.5 mm.

[0150] The thickness SP of the annular weld 42 is 10 μm or more, preferably 20 μm or more.

[0151] For example, the thickness SP of the annular weld 42 is 20 μm to 600 μm, preferably 20 μm to 300 μm, more preferably 20 μm to 200 μm, for example 20 μm to 100 μm.

[0152] According to the embodiment shown in Figures 2 and 4, the outer surface 53 of the top portion 8 of the hollow vessel 2 is substantially flat, and the outer surface 53 on which the annular weld 42 is made is substantially flush with the outer surface 53 that is not affected by the annular weld 42.

[0153] According to the embodiment shown in FIGS. 3 and 5, the upper part 8 of the hollow vessel 2 is provided with an annular recess 54 .

[0154] The annular recess 54 is located radially outside of the radial space between the free end 13 of the upper portion 8 of the hollow vessel 2 and the lid 30 .

[0155] The annular recess 54 is arranged radially outwardly of the free end 29 of the connecting portion 21 of the insert 15 made of electrically conductive material.

[0156] The annular recess 54 includes a bottom wall 55 bounded by two opposing side walls 56 .

[0157] The annular weld 42 is disposed within the annular recess 54 and on a bottom wall 55 of the annular recess 54 .

[0158] The distance radially separating the two opposing side walls 56 of the annular recess defines the radial extension ER of the annular recess 54 .

[0159] The axial extension of one of the two opposing side walls 56 of the annular recess 54 defines an axial extension EA of the annular recess 54 .

[0160] The radial extension ER of the recess 54 may be 0.2 mm to 4 mm, preferably 0.4 mm to 3 mm, in particular 0.5 mm to 2 mm, for example about 1.5 mm.

[0161] The radial extension ER of the recess 54 is preferably at least 30 times the thickness SP of the annular weld 42, more preferably at least 20 times, more preferably at least 15 times, for example at least about 10 times the thickness SP of the annular weld 42.

[0162] The axial extension EA of the recess 54 is 50 μm or more and 800 μm or less, preferably 150 μm or more and 600 μm or less, and more preferably 200 μm or more and 500 μm or less, for example, about 400 μm.

[0163] According to the embodiment shown in Figures 6 and 7, the weld 42 is a spot weld 42 that starts at the outer surface 53 of the top 8 of the hollow container 2 and reaches the peripheral portion 31 of the lid 30 across the connection portion 21 of the insert 15 made of conductive material.

[0164] The spot welds 42 include weld locations 43 arranged along a substantially circular path on the outer surface 53 of the top portion 8 of the hollow vessel 2, as shown diagrammatically in Figures 6 and 7 (which depict a top view of a portion of the battery 1).

[0165] The welds 43 are preferably equally spaced from one another along the circular path.

[0166] The number of the welded points 43 is preferably 4 or more and 60 or less, and more preferably 8 or more and 40 or less.

[0167] In this embodiment, the free end 29 of the connecting portion 21 of the insert 15 made of conductive material directly faces the external environment. At the free end 29 of the connecting portion 21 of the insert 15 made of conductive material, the battery components 1 do not overlap in the axial direction.

[0168] The spot weld 42 does not contain any filler material and is a mutual fusion of the connecting portion 21 of the insert 15 made of conductive material, the top portion 8 of the hollow vessel 2 and the peripheral portion 31 of the lid 30 .

[0169] The welds 43 are substantially visible when the battery 1 is assembled and appear as circumferentially aligned dots on the outer surface 53 of the top portion 8 of the hollow vessel 2 .

[0170] The spot weld 42 is located radially outside of the radial space between the free end 13 of the top 8 of the hollow vessel 2 and the lid 30 .

[0171] The spot weld 42 is disposed radially outward of the free end 29 of the connecting portion 21 of the insert 15 made of electrically conductive material.

[0172] Each weld 43 has a diameter DS (understood as the diameter of the circumference that most closely approximates the weld 43) of 20 μm to 400 μm, preferably 20 μm to 300 μm, more preferably 20 μm to 100 μm, for example about 60 μm.

[0173] The diameter DS of all the welds 43 is substantially the same.

[0174] According to the embodiment shown in FIG. 7 , the outer surface 53 of the top portion 8 of the hollow vessel 2 is substantially flat, and the outer surface 53 on which the annular weld 42 is made is substantially flush with the outer surface 53 that is not affected by the annular weld 42.

[0175] According to the embodiment shown in FIG. 7, the upper part 8 of the hollow vessel 2 is provided with an annular recess 54 .

[0176] The annular recess 54 is located radially outward of the radial space between the free end 13 of the upper portion 8 of the hollow vessel 2 and the lid 30 .

[0177] The annular recess 54 is arranged radially outwardly of the free end 29 of the connecting portion 21 of the insert 15 made of electrically conductive material.

[0178] The annular recess 54 includes a bottom wall 55 bounded by two opposing walls 56 .

[0179] The spot weld 42 is disposed within the annular recess 54 and on the bottom wall 55 of the annular recess 54 .

[0180] The distance radially separating the two radially opposed side walls 56 of the annular recess defines the radial extension ER of the annular recess 54 .

[0181] The axial extension of one of the two opposing side walls 56 of the annular recess 54 defines an axial extension EA of the annular recess 54 .

[0182] The radial extension ER of the recess 54 is 0.2 mm to 4 mm, preferably 0.4 mm to 3 mm, more preferably 0.5 mm to 2 mm, for example about 1.5 mm.

[0183] The radial extension ER of the recess 54 is preferably at least 30 times the diameter DS of each weld point 43, more preferably at least 20 times the diameter DS of each weld point 43, even more preferably at least 15 times the diameter of each weld point 43, for example at least about 10 times the diameter DS of each weld point 43.

[0184] The axial extension EA of the recess 54 is 50 μm or more and 800 μm or less, preferably 150 μm or more and 600 μm or less, and more preferably 200 μm or more and 500 μm or less, for example, about 400 μm.

[0185] According to the embodiment shown in figures 8 and 9, a weld 42 is obtained at the free end 29 of the connection portion 21 of the insert 15 made of electrically conductive material.

[0186] In this embodiment, the weld 42 at least partially fills the radial space between the free end 13 of the top part 8 of the hollow vessel 2 and the lid 30 (as shown diagrammatically in FIG. 8).

[0187] In this embodiment, the welding melts the free end 29 of the connecting portion 21 of the insert 15 made of electrically conductive material onto the free end 13 of the top portion 8 of the hollow vessel 2 and onto the lid 30 .

[0188] In this embodiment, the weld 42 is annular, as shown in FIG.

[0189] To assemble the battery 1, it is envisaged to provide the hollow container 2, the lid 30, the insert 15 made of conductive material and the electrochemical cell 9 as elements separated from one another.

[0190] It is then envisaged that an insert 15 made of a conductive material is mechanically and electrically connected to the anode of the electrochemical cell 9 .

[0191] This operation is carried out by welding an anode to the contact portion 21 of the insert 15 made of conductive material. In particular, it is envisaged to weld the anode surface 19 to all fins 22 of the contact portion 20 of the insert 15 made of conductive material.

[0192] The assembly consisting of the electrochemical cell 9 and an insert 15 made of conductive material is then inserted into the interior space 7 of the hollow vessel 2 with the anode facing the top 8 of the hollow vessel 2 .

[0193] It is then envisaged that the interior space 7 of the hollow vessel 2 is closed with a lid 30 .

[0194] This is carried out by forming an overlapping area 50 in which the upper part 8 of the hollow vessel 2 is located axially above the lid 30 and above the connecting portion 21 of the insert 15 made of conductive material.

[0195] Closing the internal space 7 of the hollow container 2 with the lid 30 can be carried out by the following procedure.

[0196] The connecting portion 21 of the insert 15 made of electrically conductive material is in direct electrical and physical contact with the upper portion 8 of the hollow vessel 2 .

[0197] This is carried out by at least partially overlapping the connecting portion 21 of the insert 15 made of electrically conductive material with the top portion 8 of the hollow vessel 2 .

[0198] 13, the connecting portion 21 of the insert 15 made of conductive material is placed in the upper portion 8 of the hollow vessel 2, with the curved portion 27 of the connecting portion 21 overlapping the curved portion 11 of the upper portion 8 of the hollow vessel 2. The further straight portion 28 of the connecting portion 21 contacts the further straight portion 12 of the upper portion 8 of the hollow vessel 2. The straight portion 26 of the connecting portion 21 contacts the straight portion 10 of the upper portion 8 of the hollow vessel 2.

[0199] The connecting portion 21 of the insert 15 made of electrically conductive material is radially completely received within the upper portion 8 of the hollow vessel 2 .

[0200] It is then envisaged that the peripheral portion 31 of the lid 30 is brought into direct physical contact with the connecting portion 21 of the insert 15 made of conductive material.

[0201] This operation envisages at least partially overlapping the peripheral portion 31 of the lid 30 with the connecting portion 21 of the insert made of conductive material.

[0202] As shown in FIG. 14, the peripheral portion 31 of the lid 30 is placed on the connecting portion 21 of the insert 15 made of conductive material such that the straight portion 32 of the peripheral portion overlaps the curved portion 27 of the connecting portion 21 .

[0203] It is then assumed that the connection portion 21 of the insert 15 made of a conductive material, the upper portion 8 of the hollow container 2, and the peripheral portion 31 of the lid 30 are mechanically joined together, so that the peripheral portion 31 of the lid 30 is brought into electrical contact with the upper portion 8 of the hollow container 2.

[0204] This operation is carried out by cold plastic deformation of at least the connection portion 21 of the insert 15 made of electrically conductive material and of the upper portion 8 of the hollow vessel 2 .

[0205] As shown in FIG. 15, only the connecting portion 21 of the insert 15 made of conductive material and the upper portion 8 of the hollow vessel 2 are plastically deformed.

[0206] Such deformation envisages plastic deformation of the connecting portion 21 of the insert 15 made of conductive material to form the curved portion 41. By the same plastic deformation operation, the upper portion 8 of the hollow container 2 is also plastically deformed to form the curved portion 40. Thus, the curved portion 41 of the connecting portion 21 and the curved portion 40 of the upper portion 8 are formed simultaneously.

[0207] Due to plastic deformation of the connection portion 21 of the insert 15 made of a conductive material and the upper portion 8 of the hollow container 2, the peripheral portion 31 of the lid 30 is permanently restrained to the container 2, so that the peripheral portion 31 of the lid 30 is in direct and permanent electrical contact with the upper portion 8 of the hollow container 2 (and the connection portion 21 of the insert 15 made of a conductive material).

[0208] The plastic deformation of the connecting portion 21 of the insert 15 made of electrically conductive material and the top portion 8 of the hollow vessel 2 is performed by simultaneously cold bending the further straight portion 12 of the top portion 8 and the further straight portion 28 of the connecting portion 21 onto the peripheral portion 31 of the lid 30. Due to the plastic deformation of the connecting portion 21 of the insert 15 made of electrically conductive material and the top portion 8 of the hollow vessel 2, the free end 29 of the connecting portion 21 is radially positioned between the lid 30 and the free end 13 of the top portion 8.

[0209] Once the interior space 7 of the hollow container 2 with the lid 30 is formed and the overlapping area 50 is formed, the connecting portion 21 of the insert 15 made of conductive material, the top portion 8 of the hollow container 2 and the lid 30 are welded at the overlapping area 50.

[0210] This operation is carried out by machining with a welding machine facing the outer surface 53 of the top 8 of the hollow vessel 2 .

[0211] In the embodiment of Figures 2-7, it is assumed that the weld 42 is performed using a laser welder.

[0212] The laser welding machine applies a laser beam to the outer surface 53 of the top 8 of the hollow container 2, melting the connection portion 21 of the top 8 of the hollow container 2 and the insert 15 made of a conductive material until the laser beam reaches the peripheral portion 31 of the lid 30.

[0213] The irradiated laser light does not cross the periphery 31 of the lid 30 .

[0214] The weld 42 does not cross the periphery 31 of the lid 30 and continues to seal the space 7 liquid-tight.

[0215] The size of the spot of the laser welder that reaches the outer surface 53 of the top 8 of the hollow vessel 2 is substantially equal to the radial thickness SP of the weld 42, if the weld 42 is assumed to be annular.

[0216] The size of the spot of the laser welder that reaches the outer surface 53 of the top 8 of the hollow vessel 2 is substantially equal to the diameter DS of the weld point 43 when considering spot welding.

[0217] To perform the weld 42, the laser welder irradiates the outer surface 53 of the top 8 of the hollow vessel 2 with a laser beam at a fluence (energy per unit area) in the range of 40 to 4000 joules / cm2, more preferably 80 to 3000 joules / cm2, more preferably 150 to 2200 joules / cm2, more preferably 220 to 850 joules / cm2, for example 400 to 650 joules / cm2.

[0218] The output of the laser welder is between 600 watts and 2500 watts, more preferably between 700 watts and 2000 watts, even more preferably between 850 watts and 1800 watts, and even more preferably between 1000 watts and 1600 watts, for example about 1300 watts.

[0219] Preferably, the feed speed of the laser beam along the outer surface 53 of the top 8 of the hollow vessel 2 during welding is between 100 mm / sec and 1500 mm / sec, more preferably between 150 mm / sec and 1000 mm / sec, even more preferably between 200 mm / sec and 700 mm / sec, more preferably between 220 mm / sec and 680 mm / sec, for example about 400 mm / sec.

[0220] In the embodiment of FIGS. 2 to 5, the annular weld 42 is obtained by directing a beam emitted by a laser welder along a circular trajectory on the outer surface 53 of the top part 8 of the hollow vessel 2 .

[0221] This can be done by rotating the laser beam around a circular orbit and fixing the battery 1, or by rotating the battery 1 and fixing the laser beam.

[0222] In these embodiments, the laser beam runs uninterrupted throughout the welding process.

[0223] In the embodiment of figures 6 and 7, the spot weld 42 is obtained by directing a beam from a laser welding machine along a circular trajectory to the location where the weld point 43 is to be provided.

[0224] This can be accomplished by rotating the laser beam around a circular orbit and fixing the battery 1, or by rotating the battery 1 and fixing the laser beam.

[0225] In these embodiments, the laser beam is pulsed, i.e., interrupted, between weld points 43 .

[0226] In the embodiment of figures 8 and 9, the weld 42 is obtained by melting the free end 29 of the connecting portion 21 of the insert 15 made of electrically conductive material.

[0227] This operation can be performed using a conventional or laser welder.

[0228] The free end 29 of the connecting portion 21 of the insert 15 made of electrically conductive material is melted so as to at least partially fill the radial space between the free end 13 of the upper portion 8 of the hollow vessel 2 and the lid 30 .

[0229] This completes the assembly of the battery 1.

Claims

1. a hollow vessel (2) having a side wall (3) and a bottom wall (4) defining an interior space (7), the top (8) being axially opposite the bottom wall (4) and including an outer surface (53); an electrochemical cell (9) inserted into the interior space (7) of the hollow vessel (2); an insert (15) made of a conductive material mechanically and electrically connected to a pole of the electrochemical cell (9); a lid (30) arranged to close the hollow vessel (2) at the top (8); an overlapping region (50) in which the upper portion (8) of the hollow container (2) is located axially above the lid (30) and above the connecting portion (21) of the insert (15) made of conductive material; a weld (42) between at least the connecting portion (21) of the insert (15) made of the conductive material and the top portion (8) of the hollow vessel (2), the weld (42) being arranged in the overlapping area (50) on the side facing the outer surface (53) of the top portion (8) of the hollow vessel (2), Battery (1).

2. the weld (42) joins the connecting portion (21) of the insert (15) made of conductive material, the top (8) of the hollow container (2) and the lid (30); 2. The battery (1) according to claim 1.

3. In the overlapping region (50), the connecting portion (21) of the insert (15) made of conductive material is axially inserted between and in contact with the top (8) and the lid (30) of the hollow container (2).

3. A battery (1) according to claim 1 or 2.

4. In the overlapping region (50), the upper portion (8) of the hollow container (2) is configured so as not to overlap axially with the free end (29) of the connecting portion (21) of the insert made of conductive material. A battery (1) according to any one of claims 1 to 3.

5. the weld (42) being an annular weld across the outer surface (53) of the top (8) of the hollow vessel (2) and reaching at least the connecting portion (21) of the insert (15) made of conductive material; A battery (1) according to any one of claims 1 to 4.

6. the weld (43) being a spot weld across the outer surface (53) of the top (8) of the hollow vessel (2) and reaching at least the connecting portion (21) of the insert (15) made of conductive material; A battery (1) according to any one of claims 1 to 4.

7. The annular weld (42) has a radial thickness (SP) of 30 μm or more and 300 μm or less.

6. The battery (1) according to claim 5.

8. the outer surface (53) of the top (8) of the hollow vessel (2) is provided with a recess (54) at the weld (42); A battery (1) according to any one of the preceding claims.

9. The upper portion (8) of the hollow vessel (2) has a thickness of 0.1 mm to 0.8 mm, preferably 0.2 mm to 0.6 mm. A battery (1) according to any one of the preceding claims.

10. the weld (42) is disposed on the free end (29) of the connecting portion (21) of the insert (15) made of conductive material; 5. The battery (1) according to claim 4.

11. The weld (42) seals the lid (30) to the top (8) of the hollow vessel (2) and isolates the interior space (7) of the hollow vessel (2) from the outside environment. A battery (1) according to any one of claims 2 to 10.

12. the insert (15) made of conductive material is in electrical contact with at least the top (8) of the hollow vessel (2), and the lid (30) is in electrical contact with at least the top (8) of the hollow vessel (2); The battery (1) according to any one of claims 1 to 11.

13. At least the connecting portion (21) of the insert (15) made of conductive material and the top portion (8) of the hollow container (2) are plastically deformed to define a stable mechanical connection between the hollow container (2), the lid (30) and the insert (15) made of conductive material. A battery (1) according to any one of the preceding claims.

14. the insert (15) made of electrically conductive material comprises a contact portion (20) welded to the pole of the electrochemical cell (9), the connection portion (21) extending axially from the contact portion (20) towards the lid (30); A battery (1) according to any one of the preceding claims.

15. The electrode of the electrochemical cell (9) is an anode. A battery (1) according to any one of the preceding claims.

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