How to Assemble an Electric Battery
Patent Information
- Application Number
- JP2024550204
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-05-23
- Filing Date
- 2022-12-19
- Publication Date
- 2025-12-24
Smart Images
Figure 00000000_0000_ABST
Abstract
Description
[Technical field]
[0001] The present invention refers to a method for constructing an electric battery of the type that can be used in applications where electrical energy needs to be made available. [Background technology]
[0002] An electric battery, also called a secondary electrochemical cell or secondary cell, 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 this oxidation-reduction process.
[0003] The electric battery has a hollow container having an interior cavity into which is inserted an electrochemical cell formed by a positive electrode, a negative electrode, and a separator disposed between the positive electrode and the negative electrode, the negative electrode being electrically connected to the bottom surface of the container and the positive electrode being electrically connected to the top surface 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 on which are laid anode material, separator material, and cathode material, in the form of a continuous thin film or sheet. The multilayer thus constructed is rolled on itself and placed in the cavity of the container. The cathode material is placed in electrical contact with an electrode placed at the bottom of the hollow container and is electrically insulated from the container itself. The anode material is placed in electrical contact with a lid, which is placed to close the container and creates a further electrode.
[0005] Examples of such applications include lithium ion secondary batteries, nickel cadmium secondary batteries, and nickel metal hydride secondary batteries.
[0006] In the applicant's experience, to assemble an electric battery of the type briefly described above, first an insert made of conductive material, for example copper, is welded to the anode material of an electrochemical cell. The electrochemical cell is then inserted into the cavity of a hollow vessel. At this point, the side wall of the hollow vessel must be electrically connected to the anode material, and so the insert made of conductive material located inside the hollow vessel is welded to the inner surface of the side wall of the hollow vessel. Once welded, the hollow vessel is closed with a lid that is placed in electrical contact with the side wall of the hollow vessel, so that the lid assumes the same electrical potential as the side wall of the hollow vessel.
[0007] The applicant has realised that in the method of assembling an electric battery briefly described above, welding an insert made of conductive material inside the cavity of the hollow vessel and to the inner surface of the side wall of the hollow vessel may be difficult or in any case expensive from a large scale production standpoint.
[0008] Since this welding is performed when the electrochemical cell is already inserted in the hollow vessel, the Applicant has observed in practice that the space available for welding between the insert made of conductive material and the inner surface of the side wall of the hollow vessel may be very limited.
[0009] The applicant has also noticed that if welding residues reach the electrochemical cell during the welding operation between the insert made of conductive material and the inner surface of the side wall of the hollow container, the correct operation of the electric battery may be impaired.
[0010] The applicant has realised that the method of assembling an electric battery briefly described above could be improved.
[0011] The Applicant has indeed realised that after the electrochemical cell has been placed inside the hollow vessel, the latter must be closed with a lid at the free rim.
[0012] The applicant has recognised that the insert made of conductive material may extend and reach into the bonding zone between the free rim of the hollow container and the lid so as to create an axial overlap area between the insert made of conductive material, the free rim of the hollow container and the lid, the free rim of the hollow container being axially outermost in the overlap area.
[0013] The applicant has therefore found that, with the lid already placed over the hollow container, it is possible to bond together at least a part of the free rim of the hollow container and at least a part of the insert made of conductive material, ensuring electrical continuity between the insert made of conductive material and the hollow container, by applying heat in this overlapping area, and the applicant has found that by applying this heat using a welding machine operating on the side of the free rim of the hollow container facing the outer surface, the weld (or welds) ensuring electrical contact between the insert made of conductive material and the hollow container is made substantially on the outer surface of the already assembled electric battery, preventing the risk of weld residues reaching the electrochemical cells and avoiding welding in very narrow spaces. Summary of the Invention
[0014] The present invention therefore relates to a method for assembling an electric battery.
[0015] Preferably, it is envisaged to provide a hollow container having side and bottom walls defining an interior cavity.
[0016] It is preferably envisaged to provide an upper portion of the hollow vessel, axially opposed to said bottom wall and having an outer surface.
[0017] Preferably, it is envisaged to provide an insert made of a conductive material having connections.
[0018] Preferably, it is envisaged that a lid will be provided.
[0019] Preferably, it is envisaged to insert an electrochemical cell into the internal cavity of said hollow vessel.
[0020] It is preferably envisaged that inserts made of a conductive material are mechanically and electrically connected to the electrodes of the electrochemical cell.
[0021] It is preferably envisaged that the internal cavity of the hollow vessel is closed with a lid, creating an overlap region in which the top of the hollow vessel is located axially above the connection between the lid and the insert made of conductive material.
[0022] It is envisaged that at least the connection portion of the insert made of conductive material and the upper portion of the hollow container are welded together in the overlapping area, preferably by applying a welding machine to the side of the upper portion of the hollow container facing the outer surface.
[0023] Applicant has determined that the weld at least between the connection of the conductive material insert and the top of the hollow vessel actually places the hollow vessel in permanent electrical contact with the conductive material insert (which in turn is in electrical contact with the electrodes of the electrochemical cell).
[0024] The applicant has also determined that by applying a welding machine to the side of the upper part of the hollow container facing the outer surface, welding can be performed to melt the area of the contact portion of the conductive material insert directly or through the upper part of the hollow container by melting it together with at least the upper part of the hollow container.
[0025] Applicant believes that this avoids the need to weld an insert of conductive material within the cavity of the hollow vessel to the inside surface of the hollow vessel.
[0026] The terms "axial and radial" are used with reference to directions contained in planes parallel and perpendicular, respectively, to the primary deployment axis of the electric battery.
[0027] The terms "radially innermost" and "radially outermost" refer to positions closer and further away, respectively, from the axis of rotation of the tire.
[0028] The terms "axially outermost" or "axially upward" refer to the location furthest from a plane perpendicular to the primary deployment axis of the electric battery and passing through the center of gravity of the electric battery.
[0029] The terms "axially-innermost" or "axially-lower" refer to a location closest to a plane perpendicular to the primary deployment axis of the electric battery and passing through the center of gravity of the electric battery.
[0030] The term "conductive material" as used herein and in the claims that follow means a material capable of passing an electric current therethrough and having a resistance of 1×10 4 Greater than 1 x 10 Siemens / meter, preferably at 20°C 5 Greater than siemens / meter, preferably 1 x 10 at 20°C 6 It refers to a material that has a conductivity greater than Siemens per meter.
[0031] The terms "mechanically join" or "mechanically couple," as used herein and in the claims that follow, mean joining two or more parts or components together such that the parts or components of the assembly form a mechanically constrained assembly.
[0032] By the term "direct physical contact," in this specification and the claims that follow, is meant physical contact between two parts or components without an intervening means between the two parts or components.
[0033] The term "direct electrical contact" as used herein and in the claims that follow means electrical continuity between two parts or components without an intervening conductive means between the two parts or components.
[0034] The term "electrical contact" as used herein and in the claims that follow 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 conductive means between the two parts or components.
[0035] The terms "plastic deformation" or "plastic deformation" as used herein and in the claims that follow mean deformation that does not disappear when the force that caused such deformation ceases.
[0036] The term "cold plastic deformation" as used herein and in the following claims refers to the treatment of metals at a treatment temperature below 40%, preferably below 30%, of the melting temperature of the metal being treated. For example, for a metallic material with a melting temperature of 1000°C, cold deformation occurs at a treatment temperature below 400°C, preferably below 300°C.
[0037] The present invention may exhibit at least one of the preferred features described below, which may be present individually or in combination with one another in the method of assembling an electric battery of the present invention, unless expressly stated otherwise.
[0038] Preferably, it is not envisaged to weld the insert made of electrically conductive material to 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.
[0039] Preferably, welding at least the connection portion of the conductive material insert and the top of the hollow container further comprises welding the conductive material insert and the lid together.
[0040] Preferably, the connection of the insert made of conductive material, the top of the hollow vessel and the lid are welded together at the same time.
[0041] Preferably, in said overlap region, the connection portion of the insert made of electrically conductive material is interposed axially between the top of the hollow vessel and the lid and in contact with them.
[0042] Preferably, creating the overlap region includes positioning the top of the hollow vessel so as to not axially overlap with a free end of the connection portion of an insert made of electrically conductive material.
[0043] Preferably, creating said overlap region includes having a radially inner free end of said connecting portion of an insert made of conductive material not axially overlapping with an upper portion of the hollow vessel.
[0044] Preferably, the welding includes performing the weld by traversing the outer surface of the upper portion of the hollow vessel at least until the connection of the insert made of the conductive material is reached.
[0045] Preferably, the welding includes performing the weld by traversing the exterior surface of the top of the hollow container and traversing the connection of the insert made of conductive material until it reaches the lid.
[0046] Preferably, the welding includes directing a beam emitted by a laser welder onto an exterior surface of the top of the hollow container.
[0047] Preferably, the spot size of the laser welder is between 30 microns and 300 microns, more preferably between 30 microns and 200 microns, even more preferably between 30 microns and 100 microns, for example about 60 microns.
[0048] Preferably, the laser welder irradiates the outer surface of the upper part of the hollow container with a laser beam having a fluence (energy per unit area) of between 50 Joules / cm2 and 5000 Joules / cm2, more preferably between 50 Joules / cm2 and 5000 Joules / cm2, more preferably between 100 Joules / cm2 and 2000 Joules / cm2, more preferably between 200 Joules / cm2 and 1000 Joules / cm2, for example between 400 Joules / cm2 and 700 Joules / cm2.
[0049] Preferably, the power of the laser welder is between 500 Watts and 3000 Watts, more preferably between 800 Watts and 2500 Watts, more preferably between 1000 Watts and 2000 Watts, more preferably between 1200 Watts and 1800 Watts, for example about 1500 Watts.
[0050] Preferably, the feed speed of the laser beam along the outer surface of the top of the hollow container during welding is between 100 millimeters / second and 2000 millimeters / second, more preferably between 150 millimeters / second and 1500 millimeters / second, more preferably between 200 millimeters / second and 800 millimeters / second, more preferably between 250 millimeters / second and 650 millimeters / second, for example about 450 millimeters / second.
[0051] Preferably, directing a beam emitted by a laser welder onto an exterior surface of the top of the hollow vessel includes creating an annular weld.
[0052] Preferably, producing the annular weld is obtained by directing a beam emitted by a laser welder along an annular path on the outer surface of the top of the hollow vessel.
[0053] Preferably, directing a beam emitted by a laser welder onto the outer surface of the top of the hollow container includes rotating said laser beam such that it travels in a circular path on the outer surface of the top of the hollow container.
[0054] Alternatively, directing a beam emitted by a laser welder onto the outer surface of the top of the hollow container preferably includes rotating the battery under the laser beam such that the laser beam travels in a circular path on the outer surface of the top of the hollow container.
[0055] Alternatively, directing a beam emitted by a laser welder onto an outer surface of the top of the hollow container preferably includes performing a spot weld.
[0056] Preferably, producing the spot weld is obtained by directing a beam emitted by a laser welder onto a spot on the outer surface of the top of the hollow container.
[0057] Preferably, in this case, directing a beam emitted by the laser welder onto the outer surface of the upper part of the hollow container includes rotating the laser beam so that it moves in a circular path on the outer surface of the upper part of the hollow container, and interrupting the emission of the laser beam at predetermined time intervals.
[0058] Alternatively, directing a beam emitted by a laser welder onto the outer surface of the upper portion of the hollow container preferably includes rotating the battery under the laser beam such that the laser beam moves in a circular path on the outer surface of the upper portion of the hollow container, and interrupting emission of the laser beam at predetermined time intervals.
[0059] Alternatively, and preferably, welding comprises melting said free end of the connection portion of the insert made of electrically conductive material.
[0060] Preferably, melting the free end of the connection portion of the insert made of conductive material comprises melting the free end radially to a top of the hollow vessel and to the lid.
[0061] Preferably, the internal cavity of the hollow vessel is closed with a lid before at least the connection part of the insert made of electrically conductive material and the top part of the hollow vessel are welded together.
[0062] Preferably, closing the internal cavity of the hollow container comprises mechanically joining a connection of an insert made of a conductive material, the top of the hollow container, and a periphery of the lid.
[0063] Preferably, mechanically joining the connection portion of the conductive material insert, the top of the hollow container, and the peripheral portion of the lid includes plastically deforming at least the connection portion of the conductive material insert and the top of the hollow container.
[0064] Preferably, the mechanical and electrical connection of the insert made of conductive material to the electrodes of the electrochemical cell is performed prior to inserting the electrochemical cell into the interior cavity of the hollow vessel.
[0065] Preferably, the connection portion of the conductive insert is placed in electrical contact with the top of the hollow container prior to mechanically joining the connection portion of the conductive insert, the top of the hollow container, and the periphery of the lid.
[0066] Preferably, the peripheral portion of the lid is placed in contact with the connecting portion of the conductive insert prior to mechanically joining the connecting portion of the conductive insert, the top of the hollow container, and the peripheral portion of the lid.
[0067] Preferably, placing the connection portion of the conductive material insert in electrical contact with the top of the hollow vessel includes at least partially overlapping the connection portion of the conductive material insert with the top of the hollow vessel.
[0068] Preferably, placing the periphery of the lid in contact with the connection portion of the conductive material insert includes placing the periphery of the lid in physical contact with the connection portion of the conductive material insert.
[0069] Preferably, placing the periphery of the lid in contact with the connection portion of the conductive material insert includes at least partially overlapping the periphery of the lid with the connection portion of the conductive material insert.
[0070] Preferably, placing the connection portion of the conductive material insert in electrical contact with the top of the hollow container precedes placing the peripheral portion of the lid in contact with the connection portion of the conductive material insert.
[0071] Preferably, placing the contact portion of the electrically conductive insert in electrical contact with the top of the hollow vessel is after inserting the electrochemical cell into the interior cavity of said hollow vessel.
[0072] Preferably, the mechanical joining of the connection portion of the conductive material insert, the top of the hollow container, and the periphery of the lid is performed after placing the periphery of the lid in contact with the connection portion of the conductive material insert.
[0073] Preferably, the connection of the insert made of conductive material, the top of the hollow container, and the periphery of the lid are mechanically joined, and the periphery of the lid is placed in electrical contact with the top of the hollow container, simultaneously.
[0074] Preferably, mechanically and electrically connecting an insert made of a conductive material to an electrode of the electrochemical cell includes mechanically and electrically connecting an insert made of a conductive material to an anode of the electrochemical cell.
[0075] Preferably, mechanically and electrically connecting an insert made of conductive material to the anode of the electrochemical cell comprises welding the anode to the insert made of conductive material.
[0076] Preferably, welding the anode to the conductive material insert comprises welding a contact of the conductive material insert to the anode of the electrochemical cell. [Brief description of the drawings]
[0077] Further characteristics and advantages of the invention will become apparent from the following detailed description of preferred embodiments thereof, given as illustrative and non-limiting examples, with reference to the accompanying drawings, in which:
[0078] [Figure 1] 1 is a schematic cross-sectional view of an electric battery constructed according to the method of the present invention; [Diagram 2] FIG. 2 is an enlarged schematic view showing a detail of the electric battery of FIG. 1 according to a first embodiment. [Diagram 3] FIG. 2 is an enlarged schematic view showing a detail of the electric battery of FIG. 1 according to a second embodiment; [Figure 4] FIG. 4 is a detail in a top view of the detail of FIG. 3. [Diagram 5]FIG. 5 is a detail in a top view of the detail of FIG. [Figure 6] 4 is a detail in top view of the same detail of FIG. 3 in a further embodiment. [Figure 7] 5 is a detail in top view of the same detail of FIG. 4 in a further embodiment. [Figure 8] FIG. 4 is an enlarged schematic view of a detail of the electric battery of FIG. 1 according to a third embodiment; [Figure 9] 9 shows a detail of the top view of FIG. 8. [Figure 10] FIG. 2 is a schematic side view of the components of the electric battery of FIG. 1. [Figure 11] FIG. 2 is a schematic top view of the components of the electric battery of FIG. 1. [Figure 12] 2 is a schematic perspective view of further components of the electric battery of FIG. 1; FIG. [Figure 13] FIG. 2 is a schematic diagram of an assembly sequence for the battery of FIG. 1. [Figure 14] FIG. 2 is a schematic diagram of an assembly sequence for the battery of FIG. 1. [Figure 15] 2 is an enlarged schematic view of a detail of the electric battery of FIG. 1 according to a further embodiment; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0079] The representations in the accompanying figures are not necessarily to be understood to scale nor necessarily to respect the proportions of the various parts, in which identical or similar elements of different embodiments are indicated with the same reference signs.
[0080] An electric battery made in accordance with the assembly method of the present invention is generally designated by the reference numeral 1.
[0081] The battery 1 has a main development axis X defined therein. Also defined are 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.
[0082] For ease of exposure, reference is explicitly made to a generally cylindrical electric battery 1 whose main deployment axis X substantially coincides with the axis of symmetry of the electric battery 1 .
[0083] However, the electric battery 1 may also have a shape different from a cylindrical shape, for example the shape of a right prism having a rectangular base.
[0084] The electric battery 1 comprises a hollow container 2, a lid 30, an electrochemical cell 9 and an insert 15 made of a conductive material.
[0085] The hollow vessel 2 has a side wall 3 and a bottom wall 4. The side wall 3 and the bottom wall 4 are made as one piece of steel. The bottom wall 4 and the side wall 3 define an internal cavity 7 of the hollow vessel 2. The bottom wall 4 and the side wall 3 are preferably of the same thickness. The thickness of the side wall 3 and the bottom wall 4 is preferably between 0.2 mm and 0.6 mm, for example 0.3 mm.
[0086] The electrode 5 is disposed on the bottom wall 4 of the hollow vessel 2 and is electrically insulated from the bottom wall 4. The electrode 5 is disposed at a central position of the bottom wall 4.
[0087] In the unassembled state of the electric battery 1, the hollow container 2 has an opening 6 opposite to the bottom wall 4. The hollow container 2 has a top part 8 opposite to the bottom wall 4 along the axial direction. The top part 8 extends all around the opening 6.
[0088] The upper part 8 has an (axial) straight section 10 which, in the unassembled state of the electric battery 1, makes an annular extension of the side wall 3 (figure 13) of the hollow vessel 2. This straight section 10 is made in one piece together with the side wall 3 of the hollow vessel 2. A curved section 11 which projects radially outwards and forms a radially enlarged section of the upper part 8 and extends in the circumferential direction is connected to the straight section 10. A further (axial) straight section 12 extends from the curved section 11 and extends in the circumferential direction to form a further annular section. The upper part 8 ends in a free end 13 which is also the free end of the further straight section 12.
[0089] An electrochemical cell 9, better shown in FIG. 12, includes an anode and a cathode.
[0090] The electrochemical cell 9 is of the jelly roll or Swiss roll type and has a multilayer 14 wound on itself. The multilayer 14 has a first layer 16 made of an anode material that creates the anode of the electrochemical cell 9, and a second layer 17 made of a cathode material that creates the cathode of the electrochemical cell 9. The multilayer 10 further has a third separator layer (i.e., a further third layer) 18 that separates the first layer 16 from the second layer 17. One skilled in the art can select the materials for the first layer 16, the second layer 17, and the third layer 18 to provide the desired electrical performance for the electrochemical cell 9.
[0091] In a preferred embodiment, the first layer 16 is axially offset from the second layer 17 such that it emerges axially from the multilayer 14 wound on itself relative to the second layer 17. The portion of the first layer 16 emerging axially from the multilayer 14 is plastically deformed such that the free rim of the first layer 16 is bent to form an anode surface 19. This anode surface 19 is irregular and not continuous and has the function of increasing the contact surface of the first layer 16 at the axial end of the electrochemical cell 9.
[0092] The conductive insert 15 is preferably made of copper. As best shown in Figures 10 and 11 (where the conductive insert 15 is shown not yet assembled in the electric battery 1), the conductive insert 15 has a shape along a cross section perpendicular to the axial direction that substantially corresponds to the shape of the bottom wall 4 of the hollow vessel 2. In the embodiment shown, the shape of the conductive insert 15 along a cross section perpendicular to the axial direction is substantially circular.
[0093] The insert 15 made of electrically conductive material has a substantially flat contact portion 20. The insert 15 made of electrically conductive material further has a connection portion 21. The connection portion 21 emerges axially from a radial end of the contact portion 20 and extends axially away from the contact portion 20.
[0094] The contact portion 20 is provided with a number of fins 22. Each fin 22 is defined by a respective through notch 23 that passes axially through the contact portion 20. Each through notch 23 follows a curved path including two side portions 24 and a central portion 25 (FIG. 11). The side portions 24 extend along their respective radial directions from the central region of the contact portion 20 until they reach the peripheral region of the contact portion 20. 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 number of fins 22 is preferably 2 to 8, for example, fin 18 is 4.
[0095] Figure 10 shows a side view of the insert 15 made of conductive material (in the unassembled state). The connection part 17 has a (axial) straight section 26 which extends in the circumferential direction to form an annular section. The straight section 26 is directly connected to the contact part 20. A curved section 27 which extends in the circumferential direction and projects radially outwards and forms a radially enlarged section of the upper part 17 is connected to the straight section 26. A further (axial) straight section 28 extends from the curved section 27 and which extends 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.
[0096] The lid 30 is made of steel. The lid 30 has a shape along a cross section perpendicular to the axial direction, which shape substantially corresponds to the shape of the bottom wall 4 of the hollow vessel 2. In the illustrated embodiment, the shape of the lid 30 along a cross section perpendicular to the axial direction is substantially circular.
[0097] The lid may have one or more reinforcing ribs. The lid 30 has a peripheral portion 31 circumferentially surrounding a central portion 30a.
[0098] The peripheral portion 31 has a straight portion 32 extending radially in the unassembled state of the electric battery 1 (FIG. 14). The peripheral portion 31 terminates in a free end 33 which is also a free end of the straight portion 32.
[0099] In the assembled state of the electric battery 1, the electrochemical cell 9 is inserted into the inner cavity 7 of the hollow vessel 2 with the negative electrode facing towards the bottom wall 4. The negative electrode is in electrical connection with the electrode 5. In particular, the second layer 17 of the multilayer 14 is arranged in electrical connection with the electrode 5 arranged on the bottom wall 4 of the hollow vessel 2.
[0100] The anode is electrically connected to the insert 15 made of conductive material by welding the contact 20 to the anode. In particular, the anode surface 19 is welded to the fins 22 of the contact 20 of the insert 15 made of conductive material.
[0101] In the assembled state of the electric battery 1, a connection 21 of an insert 15 made of electrically 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 diagrammatically in FIG.
[0102] The connection portion 21 of the insert 15 made of conductive material is in 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 .
[0103] The connection 21 of the insert 15 made of electrically conductive material is in direct physical contact with the top 8 of the hollow vessel 2 .
[0104] The connection portion 21 of the insert 15 made of conductive material is further in direct physical contact with the periphery 31 of the lid 30 .
[0105] The connection portion 21 of the conductive insert 15 and the top portion 8 of the hollow vessel 2 are plastically deformed to create a stable mechanical connection between the side wall 3 of the hollow vessel 2, the lid 30 and the conductive insert 15.
[0106] The connection portion 31 of the insert 15 made of conductive material is also in direct electrical and physical contact with the periphery 31 of the lid 30 .
[0107] The upper portion 8 of the hollow vessel 2 has been plastically deformed to form a curve 40 defined between the curved portion 11 and a further straight portion 12 .
[0108] The connection part 21 of the insert 15 made of electrically conductive material is arranged radially inside the upper part 8 of the hollow vessel 2. The connection part 21 of the insert 15 made of electrically conductive material is partially encompassed by a curvature 40, as shown in figures 2, 3 and 8.
[0109] At this point, the connection portion 21 of the insert 15 made of conductive material is plastically deformed and forms a curve 41 defined between the curved portion 27 and the further straight portion 28 .
[0110] The bend 41 of the connection part 21 of the insert 15 made of conductive material is inserted into the bend 40 of the top part 8 of the hollow container 2 and receives there the peripheral part 31 of the lid 30. Said peripheral part 31 of the lid 30 is not elastically bent, i.e. is not deformed.
[0111] As shown in Figures 2, 3 and 8, in the assembled state of the battery, an overlap region 50 is provided in which the upper portion 8 of the hollow container is located axially above the lid 30 and the connection portion 21 of the insert 15 made of conductive material.
[0112] In such an overlap region 50 , the connection 21 of the insert 15 made of electrically conductive material in the axial direction is interposed between the top 8 of the hollow vessel and the lid 30 .
[0113] In particular, in the overlap region 50 , an end portion 51 of the connection 21 of the insert 15 made of electrically conductive material is interposed axially between an end portion 52 of the upper portion 8 of the hollow vessel 2 and the peripheral portion 31 of the lid 30 .
[0114] The end portion 51 of the connection portion 21 of the insert 15 made of conductive material coincides with the further straight portion 28 of the connection portion 21 of the insert 15 made of conductive material.
[0115] The end portion 52 of the top portion 8 of the hollow vessel 2 coincides with the further straight portion 12 of the top portion 8 of the hollow vessel 2 .
[0116] The top portion 8 of the hollow vessel 2 does not overlap axially with the free end 29 of the connection portion 21 of the insert 15 made of electrically conductive material.
[0117] 2, 3 and 8, the free end 13 of the upper part 8 of the hollow vessel 2 is substantially facing towards and radially spaced from the lid 30. The free end 29 of the connection part 21 of the insert 15 made of conductive material is located axially between the free end 13 of the upper part 8 of the hollow vessel 2 and the lid 30 in the radial space.
[0118] In the overlap region 50, the terminal portion 51 of the connection portion 21 of the insert 15 made of conductive material, the terminal portion 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 arranged along respective radial planes.
[0119] In the overlap region 50, the upper portion 8 of the hollow vessel 2 has an outer surface 53 facing the outside environment. This outer surface 53 is the axially outermost surface of the upper portion 8 of the hollow vessel 2.
[0120] In all embodiments of the present invention, a weld 42 is provided, located at least between the connection portion 21 of the insert 15 made of conductive material and the upper portion 8 of the hollow vessel 2, in the overlap area 50 on the side facing the outer surface 53 of the upper portion 8 of the hollow vessel 2.
[0121] A weld 42 preferably connects the connection 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 .
[0122] According to the embodiment shown in Figures 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 container 2, crossing the connection portion 21 of the insert 15 made of conductive material and reaching the peripheral portion 31 of the lid 30.
[0123] The annular weld 42 is a weld that extends continuously along a substantially 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 (which represent top views of a portion of the battery 1).
[0124] In this embodiment, the free end 29 of the connection 21 of the insert 15 made of conductive material faces directly to the outside environment. At the free end 29 of the connection 21 of the insert 15 made of conductive material, the battery components 1 do not overlap axially.
[0125] The annular weld 42 does not contain any filler material but is a mutually fused weld between the connection 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.
[0126] The annular weld 42 is substantially visible when the battery 1 is assembled and appears as a ring disposed on the outer surface 53 of the top portion 8 of the hollow vessel 2 .
[0127] The annular weld 42 is located radially outside the radial space between the free end 13 of the top part 8 of the hollow vessel 2 and the lid 30 .
[0128] The annular weld 42 is arranged radially outwardly of the free end 29 of the connecting portion 21 of the insert 15 made of electrically conductive material.
[0129] The radial thickness SP of the annular weld 42 (see FIGS. 4 and 5), understood as the weld thickness, is less than 1 millimeter, preferably less than 0.5 millimeter.
[0130] The thickness SP of the annular weld 42 is greater than 10 microns, preferably greater than 20 microns.
[0131] For example, the thickness SP of the annular weld 42 is between 20 microns and 600 microns, preferably between 20 microns and 300 microns, more preferably between 20 microns and 200 microns, such as between 20 microns and 100 microns.
[0132] 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 portion 53 of the outer surface where the annular weld 42 is made is substantially flush with the portion 53 of the outer surface that is not affected by the annular weld 42.
[0133] According to the embodiment shown in FIGS. 3 and 5, the upper part 8 of the hollow vessel 2 has an annular recess 54 .
[0134] The annular recess 54 is located radially outside the radial space between the free end 13 of the upper portion 8 of the hollow vessel 2 and the lid 30 .
[0135] The annular recess 54 is arranged radially outside the free end 29 of the connecting portion 21 of the insert 15 made of electrically conductive material.
[0136] The annular recess 54 has a bottom wall 55 bounded by two opposing side walls 56 .
[0137] The annular weld 42 is disposed within the annular recess 54 and is disposed on a bottom wall 55 of the annular recess 54 .
[0138] The distance separating the two opposing side walls 56 of the annular recess in the radial direction defines a radial extension line ER of the annular recess 54 .
[0139] The axial extension of one of the two opposing side walls 56 of the annular recess 54 defines an axial extension line EA of the annular recess 54 .
[0140] The radial extension ER of the recess 54 is between 0.2 and 4 mm, preferably between 0.4 and 3 mm, more preferably between 0.5 and 2 mm, for example about 1.5 mm.
[0141] The radial extension line ER of the recess 54 is preferably 30 times the thickness SP of the annular weld 42, more preferably 20 times the thickness SP of the annular weld 42, even more preferably 15 times the thickness SP of the annular weld 42, for example about 10 times the thickness SP of the annular weld 42.
[0142] The axial extension EA of the recess 54 is between 50 and 800 microns, preferably between 150 and 600 microns, more preferably between 200 and 500 microns, for example about 400 microns.
[0143] According to the embodiment shown in Figures 6 and 7, the weld 42 is a spot weld 42 starting from the outer surface 53 of the top 8 of the hollow container 2, crossing the connection portion 21 of the insert 15 made of conductive material, and reaching the peripheral portion 31 of the lid 30.
[0144] The spot welds 42 have weld spots 43 arranged along a substantially circular path on the outer surface 53 of the top portion 8 of the hollow container 2, as shown diagrammatically in Figures 6 and 7 (which show top views of a portion of the battery 1).
[0145] The weld spots 43 are preferably equidistant from one another along a circular path.
[0146] The number of the welding spots 43 is 4-60, preferably 8-40.
[0147] In this embodiment, the free end 29 of the connection 21 of the insert 15 made of conductive material faces directly to the outside environment. At the free end 29 of the connection 21 of the insert 15 made of conductive material, the battery components 1 do not overlap axially.
[0148] The spot weld 42 does not contain any filler material but is a mutually fused joint between the connection portion 21 of the insert 15 made of conductive material, the top portion 8 of the hollow container 2 and the peripheral portion 31 of the lid 30.
[0149] The weld spots 43 are substantially visible when the battery 1 is assembled and appear as spots aligned along the periphery and located on the outer surface 53 of the top portion 8 of the hollow vessel 2 .
[0150] The spot weld 42 is located radially outside the radial space between the free end 13 of the top 8 of the hollow vessel 2 and the lid 30 .
[0151] The spot weld 42 is arranged radially outside the free end 29 of the connection portion 21 of the insert 15 made of electrically conductive material.
[0152] The diameter DS of each weld spot 43 (understood as the diameter of the circumference closest to the weld spot 43) is between 20 microns and 400 microns, preferably between 20 microns and 300 microns, more preferably between 20 microns and 100 microns, for example about 60 microns.
[0153] All the weld spots 43 have substantially the same diameter DS.
[0154] 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 portion 53 of the outer surface where the annular weld 42 is made is substantially flush with the portion 53 of the outer surface that is not affected by the annular weld 42.
[0155] According to the embodiment shown in FIG. 7, the upper part 8 of the hollow vessel 2 has an annular recess 54 .
[0156] The annular recess 54 is located radially outside the radial space between the free end 13 of the upper portion 8 of the hollow vessel 2 and the lid 30 .
[0157] The annular recess 54 is arranged radially outside the free end 29 of the connecting portion 21 of the insert 15 made of electrically conductive material.
[0158] The annular recess 54 has a bottom wall 55 bounded by two opposing side walls 56 .
[0159] The spot weld 42 is disposed within the annular recess 54 and is disposed on a bottom wall 55 of the annular recess 54 .
[0160] The distance separating the two opposing side walls 56 of the annular recess in the radial direction defines a radial extension line ER of the annular recess 54 .
[0161] The axial extension of one of the two opposing side walls 56 of the annular recess 54 defines an axial extension line EA of the annular recess 54 .
[0162] The radial extension ER of the recess 54 is between 0.2 and 4 mm, preferably between 0.4 and 3 mm, more preferably between 0.5 and 2 mm, for example about 1.5 mm.
[0163] The radial extension line ER of the recess 54 is preferably 30 times the diameter DS of each welding spot 43, more preferably 20 times the diameter DS of each welding spot 43, even more preferably 15 times the diameter DS of each welding spot 43, for example about 10 times the diameter DS of each welding spot 43.
[0164] The axial extension EA of the recess 54 is between 50 and 800 microns, preferably between 150 and 600 microns, more preferably between 200 and 500 microns, for example about 400 microns.
[0165] According to the embodiment shown in figures 8 and 9, a weld 42 is obtained at the free end 29 of the connection 21 of the insert 15 made of electrically conductive material.
[0166] 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).
[0167] In this embodiment, the welding involves melting the free end 29 of the connection 21 of the insert 15 made of conductive material at the free end 13 of the top 8 of the hollow vessel 2 and at the lid 30 .
[0168] In this embodiment, the weld 42 is annular in shape, as shown diagrammatically in FIG.
[0169] To assemble the electric 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 separate elements.
[0170] 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 .
[0171] This operation is carried out by welding the anode to the contact portion 14 of the insert 15 made of conductive material. In particular, it is envisaged to weld the anode surface 19 to all the fins 22 of the contact portion 20 of the insert 15 made of conductive material.
[0172] The assembly consisting of the electrochemical cell 9 and the insert 15 made of conductive material is then inserted into the internal cavity 7 of the hollow vessel 2 with the anode facing towards the top 8 of the hollow vessel 2 .
[0173] It is then envisaged that the internal cavity 7 of the hollow vessel 2 is closed with a lid 30 .
[0174] This is done by creating an overlap area 50 in which the top 8 of the hollow vessel 2 is located axially above the lid 30 and the connection 21 of the insert 15 made of conductive material.
[0175] Closing the internal cavity 7 of the hollow vessel 2 with the lid 30 can be carried out according to the following operations.
[0176] The connection portion 21 of the insert 15 made of electrically conductive material is placed in direct electrical and physical contact with the upper portion 8 of the hollow vessel 2 .
[0177] This is achieved by at least partially overlapping the connection portion 21 of the insert 15 made of conductive material with the upper portion 8 of the hollow vessel 2 .
[0178] 13, the connection part 21 of the insert 15 made of conductive material is arranged in the upper part 8 of the hollow vessel 2 with the curved part 27 of the connection part 21 overlapping the curved part 11 of the upper part 8 of the hollow vessel 2. The further straight part 28 of the connection part 21 is arranged relative to the further straight part 12 of the upper part 8 of the hollow vessel 2. The straight part 26 of the connection part 21 is arranged in the straight part 10 of the upper part 8 of the hollow vessel 2.
[0179] The connection part 21 of the insert 15 made of electrically conductive material is completely enclosed in the radial direction within the upper part 8 of the hollow vessel 2 .
[0180] It is then envisaged that the peripheral portion 31 of the lid 30 is placed in direct physical contact with the connection portion 21 of the insert 15 made of conductive material.
[0181] This operation envisages at least partially overlapping the peripheral portion 31 of the lid 30 with the connection portion 21 of the insert 15 made of conductive material.
[0182] As shown in FIG. 14, the periphery 31 of the lid 30 is placed on the connection portion 21 of the insert 15 made of conductive material, with the straight portion 32 of the periphery overlapping the curved portion 27 of the connection portion 21 .
[0183] It is then envisaged that the connection portion 21 of the insert 15 made of conductive material, the upper portion 8 of the hollow container 2 and the peripheral portion 31 of the lid 30 are mechanically joined together, placing the peripheral portion 31 of the lid 30 in electrical contact with the upper portion 8 of the hollow container 2.
[0184] This operation is carried out by cold plastic deformation of at least the connection 21 of the insert 15 made of electrically conductive material and of the top portion 8 of the hollow vessel 2 .
[0185] As shown in FIG. 15, only the connection portion 21 of the insert 15 made of conductive material and the top portion 8 of the hollow vessel 2 are plastically deformed.
[0186] Such deformation provides for plastic deformation of the connection portion 21 of the insert 15 made of conductive material to form a curve 41. In the same plastic deformation operation, the upper portion 8 of the hollow container 2 is also plastically deformed to form a curve 40. In this way, the curve 41 of the connection portion 21 and the curve 40 of the upper portion 8 are formed simultaneously.
[0187] The plastic deformation of the connection portion 21 of the conductive insert 15 and the upper portion 8 of the hollow vessel 2 permanently restrains the peripheral portion 31 of the lid 30 to the containment body 2 and places the peripheral portion 31 of the lid 30 in direct and permanent electrical contact with the upper portion 8 of the hollow vessel 2 (as well as with the connection portion 21 of the conductive insert 15).
[0188] The plastic deformation of the connection 21 of the insert 15 made of conductive material and the top 8 of the hollow vessel 2 is carried out by simultaneously cold bending the further straight section 12 of the top 8 and the further straight section 28 of the connection 21 of the peripheral section 31 of the lid 30. The plastic deformation of the connection 21 of the insert 15 made of conductive material and the top 8 of the hollow vessel 2 places the free end 29 of the connection 21 radially between the lid 30 and the free end 13 of the top 8.
[0189] When the internal cavity 7 of the hollow container 2 including the lid 30 is created and the overlap region 50 is created, it is provided to weld the connection portion 21 of the insert 15 made of conductive material, the top portion 8 of the hollow container 2 and the lid 30 together in the overlap region 50.
[0190] This operation is carried out by applying a welding machine to the side of the top 8 of the hollow vessel 2 facing the outer surface 53 .
[0191] In the embodiment of Figures 2 to 7, it is envisioned that the weld 42 is performed with a laser welder.
[0192] The laser welder emits a laser beam onto the outer surface 53 of the top 8 of the hollow container 2, which traverses the top 8 of the hollow container 2 and the connection portion 21 of the conductive material insert 15 until it reaches the peripheral portion 31 of the lid 30, melting them together.
[0193] The emitted laser beam does not traverse the periphery 31 of the lid 30 .
[0194] The weld 42 does not traverse the periphery 31 of the lid 30 and continues to seal the cavity 7 liquid-tight.
[0195] The size of the spot of the laser welder reaching 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 when assumed to be annular.
[0196] 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 welding spot 43 in the case of spot welding.
[0197] 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 with a fluence (energy per unit area) of between 40 joules / cm2 and 4000 joules / cm2, more preferably between 80 joules / cm2 and 3000 joules / cm2, more preferably between 150 joules / cm2 and 2200 joules / cm2, more preferably between 220 joules / cm2 and 850 joules / cm2, for example between 400 joules / cm2 and 650 joules / cm2.
[0198] The power of the laser welder is between 600 watts and 2500 watts, more preferably between 700 watts and 2000 watts, more preferably between 850 watts and 1800 watts, more preferably between 1000 watts and 1600 watts, for example about 1300 watts.
[0199] 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 millimeters / second and 1500 millimeters / second, more preferably between 150 millimeters / second and 1000 millimeters / second, more preferably between 200 millimeters / second and 700 millimeters / second, more preferably between 220 millimeters / second and 680 millimeters / second, for example about 400 millimeters / second.
[0200] 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 path on the outer surface 53 of the top portion 8 of the hollow vessel 2 .
[0201] This can be performed by rotating the laser beam around a circular path while keeping the battery 1 stationary, or by rotating the battery 1 while keeping the laser beam stationary.
[0202] In these embodiments, the laser beam is applied uninterrupted throughout the welding process.
[0203] In the embodiment of figures 6 and 7, the spot weld 42 is obtained by directing a beam emitted by a laser welder along a circular path and to a spot where the weld spot 43 is provided.
[0204] This can be performed by rotating the laser beam around a circular path while keeping the battery 1 stationary, or by rotating the battery 1 while keeping the laser beam stationary.
[0205] In these embodiments, the laser beam is pulsed, i.e., interrupted, between each welding spot 43 and the next welding spot 43 .
[0206] In the embodiment of figures 8 and 9, the weld 42 is obtained by melting the free end 29 of the connection 21 of the insert 15 made of electrically conductive material.
[0207] This operation can be performed with a conventional welder or a laser welder.
[0208] The free end 29 of the connection 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 top part 8 of the hollow vessel 2 and the lid 30 .
[0209] In this way the electric battery 1 is fully assembled.
Claims
1. A method for assembling an electric battery (1), comprising the steps of: Providing a hollow container (2) having a side wall (3) and a bottom wall (4) defining an interior cavity (7); providing an upper portion (8) of said hollow vessel (2) axially facing said bottom wall (4) and having an outer surface (53); Providing an insert (15) made of a conductive material having a connection (21); Providing a lid (30); Inserting an electrochemical cell (9) into the internal cavity (7) of the hollow vessel (2); mechanically and electrically connecting the insert (15) made of conductive material to the electrodes of the electrochemical cell (9); closing the internal cavity (7) of the hollow vessel (2) with the lid (30), creating an overlapping area in which the top of the hollow vessel (2) is located axially above the lid (30) and the connecting portion (21) of the insert (15) made of conductive material; welding together at least the connection portion (21) of the insert (15) made of conductive material and the upper portion (8) of the hollow vessel (2) in the overlapping region (50) by applying a welding machine to the side of the upper portion (8) of the hollow vessel (2) facing the outer surface (53). A method comprising:
2. Welding together at least the connection portion (21) of the conductive material insert (15) and the top portion (8) of the hollow container (2) further comprises welding together the conductive material insert (15) and the lid (30). The method of claim 1.
3. In the overlapping region (50), the connecting portion (21) of the insert (15) made of conductive material is interposed between the upper portion (8) of the hollow container (2) and the lid (30) in the axial direction and is in contact with the upper portion (8) of the hollow container (2) and the lid (30). The method of claim 1.
4. the connection part (21) of the insert (15) made of conductive material, the top part (8) of the hollow container (2) and the lid (30) are welded together at the same time; The method of claim 3.
5. Creating the overlapping region (50) includes positioning the upper portion (8) of the hollow vessel (2) so that 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 conductive material. The method of claim 1.
6. Welding includes melting the free end (29) of the connection portion (21) of the insert (15) made of conductive material. The method of claim 5.
7. welding includes directing a beam emitted by a laser welder onto the outer surface (53) of the top (8) of the hollow container (2); The method of claim 1.
8. Closing the internal cavity (7) of the hollow container (2) comprises mechanically joining the connection portion (21) of the insert (15) made of conductive material, the top portion (8) of the hollow container (2) and the peripheral portion (31) of the lid (30). The method of claim 1.
9. Mechanically joining the connection portion (21) of the insert (15) made of conductive material, the upper portion (8) of the hollow container (2), and the peripheral portion (31) of the lid (30) includes plastically deforming at least the connection portion (21) of the insert (15) made of conductive material and the upper portion (8) of the hollow container (2). The method of claim 8.
10. the mechanical and electrical connection of the insert (15) made of conductive material to the electrodes of the electrochemical cell (9) is performed before inserting the electrochemical cell (9) into the internal cavity (7) of the hollow vessel (2); The method of claim 1.
11. Mechanically and electrically connecting the conductive material insert (15) to the electrodes of the electrochemical cell (9) includes mechanically and electrically connecting the conductive material insert (15) to the anode of the electrochemical cell (9). The method of claim 1.