Method for manufacturing an energy storage battery

Abstract

The method for manufacturing an energy storage battery (1) comprises the steps of providing an electrochemical cell (2) at least partially completed and provided with a current collector (11), providing a container (3) having a first wall (8), arranging on the outer surface of the first wall (8) an outer body (17; 25) constituting an electrode (14) of the battery (1), inserting the electrochemical cell (2) into the container (3) and bringing the current collector (11) close to the first wall (8), providing the current collector (11) with accesses (15; 22; 26) from outside the container (3) to allow a weld (24) between the current collector (11) and the outer body (17; 25) to establish an electrical connection, and welding the current collector (11) and the outer body (17; 25) to each other via the aforementioned accesses (15; 22; 26) to establish an electrical connection.

Description

[Technical field]

[0001] The present invention relates to a method for manufacturing an energy storage battery, and more generally to energy storage devices.

[0002] The meaning of "to manufacture a battery" also refers to the assembly thereof.

[0003] The present invention finds advantageous application in the manufacture of lithium-ion cylindrical batteries, to which the following description refers explicitly without loss of generality. [Background technology]

[0004] Commercially available lithium-ion batteries are assembled in three different shapes: cylindrical, prismatic, and pouch-shaped.

[0005] A cylindrical battery is formed by a cylindrical metal container having inside it a single electrochemical cell of the "jelly roll" or "Swiss roll" type formed by the anode, separator, and cathode wound together around a central pin.

[0006] Specifically, the cylindrical container is initially open on one side (i.e., has the shape of a cup with a closed first end and an open second end) to allow for the insertion of a wound electrochemical cell and an electrolyte that impregnates the wound electrochemical cell. Once formation of the battery is complete (i.e., all components are placed inside the cylindrical container), the open end of the cylindrical container is closed to form a hermetic closure.

[0007] In particular, to close the open end of the cylindrical container, a circular lid (possibly coupled to an annular gasket) is used which is connected to the cylindrical container and which deforms the upper edge of the cylindrical container itself against the lid.

[0008] Before inserting the electrochemical cell inside the cylindrical container, two current collectors are joined (in the particular case of cylindrical batteries, in the shape of a disk) at the two opposite ends of the electrochemical cell, the cathode (a current collector made of aluminum is used) and the anode (a current collector made of copper is used). Each current collector is pressed against the corresponding end of the electrochemical cell and welded to a connecting sheet of conductive strips (made of aluminum and copper) that are wound together (with an insulating separator between them) to form the electrochemical cell.

[0009] The first wall of one of the cylindrical containers has a central through hole that is engaged by an aluminum rivet (also called a rivet) with a head that is located on the outside of the cylindrical container and constitutes the positive pole of the cylindrical battery. In particular, the rivet is inserted through the through hole in the first wall of the cylindrical container through a series of plastic gaskets that isolate the rivet from the cylindrical container, and then the headless end of the rivet is forced in (i.e., plastically deformed) to form a counter-head.

[0010] When the electrochemical cell provided with the two current collectors is inserted inside the cylindrical vessel, the cathode current collector (made of aluminum) is pressed against the counter head of the rivet (previously bonded to the first wall of the cylindrical vessel) and then welded to the counter head of the rivet to make a stable connection of large elongation (the larger the contact area, the lower the electrical resistance at the contact area).

[0011] Typically, the welding between the cathode current collector and the counter head of the rivet is performed by using the (reduced in size) central hole of the electrochemical cell to apply heat to the cathode current collector and thus melt the metal (aluminium) locally. Indeed, it is generally not possible to apply heat to the area between the cathode current collector and the counter head of the rivet passing through the first wall of the cylindrical vessel, because doing so would damage the plastic gasket that isolates the rivet from the cylindrical vessel due to excessive heating. Summary of the Invention

[0012] Applicant feels a need to provide a method for manufacturing energy storage batteries that allows for operation at high production rates (measured as batteries manufactured per unit time) while ensuring the achievement of a high quality end product.

[0013] The applicant first observed that the geometric proportions between the conventional electrochemical cells and the relative central hole do not facilitate performing welding through the central hole itself, especially at high production rates. In particular, it is complicated to apply heat, for example, to the bottom of this hole (i.e. to the cathode current collector located at the end of the central hole of the electrochemical cell). As a result, the welding operation requires high precision, is particularly slow, and therefore requires very long execution times, and cannot operate at high production rates (measured as cylindrical cells produced per unit time).

[0014] Applicant has also observed that any metal splash (which forms small metal chips upon cooling) produced during welding may remain trapped inside the holes of the jelly roll, or in either case inside the battery, and thus may "contaminate" the electrochemical cell, causing small localized short circuits which may impair its performance over time, or even cause it to deteriorate prematurely.

[0015] Applicant has finally observed that conventional welds through holes in the jelly roll are difficult to inspect once made, making subsequent quality control difficult or extremely slow, both on the line and in the finished product.

[0016] The applicant therefore realises that even temporary access from outside the battery container during welding can eliminate the presence of metal debris from inside the container and also facilitates the insertion of the welding head at high speeds which do not find obstacles in its path, thus enabling it to operate at high speeds whilst maintaining the quality of the final product.

[0017] The applicant has also noted that by using so-called "transparent" welding, it is possible to ensure external access to the conductors being welded without necessarily exposing / visible them from the outside.

[0018] In other words, the conductors to be welded are not visible from the outside, but are advantageously accessible from the outside to receive the heat / energy required for welding and therefore can be delivered from outside the vessel.

[0019] Thus, according to the present invention there is provided a method of manufacturing a battery for energy storage, said method comprising the steps of: Providing an at least partially completed electrochemical cell having a current collector; Providing a container having a first wall; disposing an outer body on an outer surface of the first wall, the outer body constituting an electrode of the battery; inserting an electrochemical cell into the container with a current collector proximate to the first wall; providing access to the current collector from outside the container to allow for a weld between the current collector and the outer body; welding the current collector and the outer body together at the access to establish an electrical connection; Includes.

[0020] Preferably, the access includes a first through hole formed in the first wall.

[0021] Preferably, the access includes a second hole made in the outer body and positioned in at least partial alignment with the first hole when the outer body is positioned on the outer surface of the first wall, and the welding is performed at the second hole.

[0022] Preferably, the weld is made from the outside of the container through the second hole and operating from the opposite side of the first wall to the electrochemical cell.

[0023] Preferably, the weld is at least partially located inside the second hole.

[0024] Preferably, when the outer body is disposed on the outer surface of the first wall, the second bore is coaxial with the first bore.

[0025] In an embodiment, the second hole in the outer body is a through hole.

[0026] In an embodiment, the second hole in the outer body is blind and defines a recess into which the protrusion of the current collector is inserted.

[0027] In an embodiment, the current collector includes a protrusion that is inserted into the first hole in the first wall and the second hole in the outer body, and a weld is made between the outer body and the protrusion of the current collector.

[0028] In an embodiment, after the protrusion is inserted into the second hole, the outer surface of the protrusion is flush with the outer surface of the outer body.

[0029] In an embodiment, the outer surface of the protrusion initially protrudes from the outer surface of the outer body after inserting the protrusion into the second hole, and the second central hole of the outer body has an outer flaring, and the method further includes the step of at least partially bucking the outer surface of the protrusion against the outer body so as to make the outer surface of the protrusion flush with the outer surface of the outer body.

[0030] In an embodiment, a rivet is provided that engages the first hole in the first wall and includes a head disposed on the exterior of the container and constituting an outer body, and a counter head disposed on the interior of the container.

[0031] In an embodiment, the rivet initially has only a head, whereas the counterhead is obtained after inserting the rivet through the first hole in the first wall by forcing the rivet into the inner surface of the first wall.

[0032] Preferably, the outer body consists only of the connecting elements which are located entirely on the outside of the container.

[0033] Preferably, the projection of the current collector is surrounded at its base by a fastening element whose function is to compress the insulating gasket against the inner surface of the first wall.

[0034] In an embodiment, the current collector does not have a protrusion and the welding is performed inside the second hole in the outer body.

[0035] Preferably, the method comprises the steps of: placing a first insulating gasket inside the access to line the access; disposing a second insulating gasket between the outer body and an exterior surface of the first wall; disposing a third insulating gasket between the inner surface of the first wall and the current collector; Further includes:

[0036] In an embodiment, the weld is made from the outside of the container, through the outer body, passing from side to side across the outer body and coming from the opposite side of the electrochemical cell to the first wall.

[0037] The appended claims set forth embodiments of the invention forming an integral part thereof.

[0038] It is also evident that the product obtained by the method according to the invention, in the embodiment providing a weld worked "through", exhibits this type of weld among its characteristics.

[0039] The present invention will now be described with reference to the accompanying drawings, in which several non-limiting embodiments are shown. [Brief description of the drawings]

[0040] [Figure 1] FIG. 1 is a schematic side view of a cylindrical battery. [Diagram 2]2 is an enlarged schematic side view of a first end of the cylindrical battery of FIG. 1. [Diagram 3] FIG. 3 is a schematic diagram showing a sequence of operations for making a positive electrode for the cylindrical battery of FIG. 2. [Figure 4] FIG. 3 is a schematic diagram showing a sequence of operations for making a positive electrode for the cylindrical battery of FIG. 2. [Diagram 5] FIG. 3 is a schematic diagram showing a sequence of operations for making a positive electrode for the cylindrical battery of FIG. 2. [Figure 6] FIG. 3 is a schematic diagram showing a sequence of operations for making a positive electrode for the cylindrical battery of FIG. 2. [Figure 7] FIG. 3 is a schematic diagram showing a sequence of operations for making a positive electrode for the cylindrical battery of FIG. 2. [Figure 8] FIG. 3 is a schematic diagram showing a sequence of operations for making a positive electrode for the cylindrical battery of FIG. 2. [Figure 9] FIG. 3 is a schematic diagram showing a sequence of operations for making a positive electrode for the cylindrical battery of FIG. 2. [Figure 10] 3A-3C are schematic diagrams illustrating some operational variations for making the positive electrode of the cylindrical battery of FIG. 2. [Figure 11] 3A-3C are schematic diagrams illustrating some operational variations for making the positive electrode of the cylindrical battery of FIG. 2. [Figure 12] FIG. 2 is a schematic plan view of a first end of the cylindrical battery of FIG. 1. [Figure 13] 2 is an enlarged schematic side view of a first end of a variation of the cylindrical battery of FIG. 1. [Figure 14] 2 is an enlarged schematic side view of a first end of a further variation of the cylindrical battery of FIG. 1. FIG. [Figure 15] FIG. 15 is a schematic diagram showing a sequence of operations for making the positive electrode of the cylindrical battery of FIG. 14. [Figure 16] FIG. 15 is a schematic diagram showing a sequence of operations for making the positive electrode of the cylindrical battery of FIG. 14. [Figure 17] 15A-15C are schematic diagrams illustrating some operational variations for making the positive electrode of the cylindrical battery of FIG. 14. [Figure 18]15A-15C are schematic diagrams illustrating some operational variations for making the positive electrode of the cylindrical battery of FIG. 14. [Figure 19] 2 is an enlarged schematic side view of a first end of another modified example of the cylindrical battery of FIG. 1. FIG. [Figure 20] 2 is an enlarged schematic side view of a first end of another modified example of the cylindrical battery of FIG. 1. FIG. [Figure 21] 2 is an enlarged schematic side view of a first end of another modified example of the cylindrical battery of FIG. 1. FIG. [Figure 22] 2 is an enlarged schematic side view of a first end of another modified example of the cylindrical battery of FIG. 1. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0041] In FIG. 1, the numeral 1 generally indicates an energy storage battery, and the battery 1 shown is cylindrical in shape, merely by way of example and without thereby limiting the scope of the invention.

[0042] The battery 1 comprises a cylindrically shaped electrochemical cell 2 of the "jelly roll" or "Swiss roll" type formed by a number of sheets superimposed and thus rolled together to take a cylindrical shape, and a cylindrical container 3 that surrounds the electrochemical cell 2 inside and has a centrally located longitudinal axis of symmetry 4. In particular, the cylindrical electrochemical cell 2 consists of a spiral winding of a set of four strips: a conductive strip of a metal-based material (typically aluminum) constituting the cathode, a separator strip made of a porous material (later immersed in a liquid electrolyte), a conductive strip made of a metal-based material (typically copper) constituting the anode, and a separator strip made of a porous material (later immersed in a liquid electrolyte). In other words, the four superimposed strips form a composite material (i.e. a "sandwich" of the four strips) that is spirally wound on itself to form the cylindrical electrochemical cell 2. The electrochemical cell 2 has, in the center, a through hole 5 (necessary for the realization of the spiral winding) that passes across it.

[0043] The container 3 has a cylindrical side wall 6, a first end 7 that is initially closed by a first wall 8 (i.e., by a lower portion) that is seamlessly connected to the side wall 6, and a second end 9 opposite the first end 7, the second end 9 being initially open to allow the electrochemical cell 2 to be inserted into the container 3, and then closed and sealed. In particular, a lid 10 is arranged at the second end 9 of the container 3 (if the cylindrical cell is circular) that closes the second end 9 (i.e., constituting the upper base of the container 3).

[0044] Before inserting the electrochemical cell 2 inside the container 3, two current collectors 11 and 12 are joined (disk-shaped in the particular case of a cylindrical battery) at the two opposite ends of the electrochemical cell 2, a cathode (aluminum current collector 11 is used) and an anode (copper current collector 12 is used). Each terminal current collector 11 or 12 constitutes a current collector (cathode in the case of the aluminum current collector 11 and anode in the case of the copper current collector 12) that collects the current generated inside the electrochemical cell 2 to allow such current to circulate outside the electrochemical cell 2. Each terminal current collector 11 or 12 is pressed against the corresponding end of the electrochemical cell 2 and welded to a connecting lamella of conductive strips (made from aluminum and copper) that are wound together (with an insulating separator between them) to constitute the electrochemical cell 2.

[0045] The battery 1 includes a negative electrode 13 disposed at the second end 9 and fabricated within the lid 10, and a positive electrode 14 (with sufficient electrical insulation as described below) disposed on the first wall 8.

[0046] Generally, according to the invention, the current collector 11 is arranged to communicate with the outside of the container 3 by at least one access 15 , 22 , 26 .

[0047] As shown in Figure 2, the access includes a hole 15. In particular, the first wall 8 of the container 3 has a through hole 15 (better shown in Figure 5) (in this case the center) that is engaged by an aluminum rivet 16 (also called a rivet, see Figure 7) having a head 17 (i.e., the head 17 is a terminal that constitutes the positive electrode 14 of the battery 1) that is located on the outside of the container 3 (i.e., outside the first wall 8 of the container 3) and constitutes the positive electrode 14 of the battery 1.

[0048] In particular, the rivet 16 is inserted into the hole 15 in the first wall 8 of the container 3 via a series of plastic insulating gaskets 18, 19, and 20 that isolate the rivet 16 from the container 3 (in particular from the first wall 8 of the container 3), and then the headless end of the rivet 16 is pressed (i.e. plastically deformed) to form a counterhead 21. In other words, the rivet 16 includes a head 17 that engages the through hole 15 in the first wall 8 of the container 3 and is located on the outside of the first wall 8 of the container 3 and constitutes the positive electrode 14 of the battery 1, and a counterhead 21 that is located on the inside of the first wall 8 of the container 3 and thus faces the cathode current collector 11.

[0049] The insulating gasket 18 has a cylindrical shape and lines the inside of the through hole 15 in the first wall 8 of the vessel 3 and isolates the rivet 16 from the wall of the hole 15 .

[0050] The insulating gasket 19 is disc-shaped and is interposed between the head 17 of the rivet 16 and the first wall 8 of the container 3 to isolate the rivet 16 from the outer surface of the first wall 8 .

[0051] The insulating gasket 20 has a disk shape and is interposed between the counter head 21 of the rivet 16 and the first wall 8 of the container 3 to isolate the rivet 16 from the inner surface of the first wall 8. In other words, the two insulating gaskets 19, 20 are arranged on either side of the first wall 8 of the container 3.

[0052] The rivet 16 is a through hole, cylindrical in the illustrated example, with a central hole 22 passing across the rivet 16, and the current collector 11 has a protrusion 23 (centrally located and cylindrical in the illustrated example) that cantilevers up from the current collector 11, with the hole 22 of the rivet 16 engaging the protrusion 23 of the current collector 11. Furthermore, the hole 22 is located at least partially in alignment (preferably coaxial) with the hole 15 when the head 17 is located on the outer surface of the first wall 8. In general, the protrusion fits into the access 15, 22, 25, which in this case also includes the hole 22.

[0053] The holes 22 may also be blind holes and thus constitute a recess (seat, cavity, housing), i.e., the rivet 16 may include blind holes 22 that constitute a recess (as shown in Figures 19 and 20) as an alternative to the through holes 22.

[0054] Preferably, the hole 22 of the rivet 16 accommodates the protrusion 23 of the current collector 11 with reduced or minimal clearance (some clearance is necessary to fit the protrusion 23 of the current collector 11 into the hole 22 of the rivet 16, but this clearance needs to be small to facilitate subsequent joining of the protrusion 23 with the hole 22). Between the rivet 16 and the protrusion 23 of the current collector 11 is a weld 24 that is preferably annular (i.e., forms a closed ring as shown in FIG. 12 ) (e.g., the weld 24 can be made by a laser) that provides both a stable mechanical connection between the rivet 16 and the protrusion 23 of the current collector 11 and a low resistance electrical connection between the rivet 16 and the protrusion 23 of the current collector 11.

[0055] The term welding generally refers to the result of joining / bonding / fastening of elements, regardless of the technique by which the operation is performed. For example, the joining / bonding / fastening can be by heat and / or mechanical pressure and / or vibration, or can result from crimping or riveting of the parts to be joined. In an embodiment, the welding can be melting between the elements (with or without a filler metal), e.g. laser welding (mentioned below only as an example), ultrasonic welding.

[0056] A method for producing the positive electrode 14 of the battery 1 will now be described with reference to FIGS.

[0057] As shown in FIG. 3, the current collector 11 provided with the protrusions 23 is connected to the electrochemical cell 2, and the current collector 11 provided with the protrusions 23 is better shown in FIG.

[0058] As shown in FIG. 5, a through hole 15 (centrally shown) is made through the first wall 8 of the container 3 .

[0059] As shown in FIG. 6 , the first wall 8 of the container 3 is coupled with insulating gaskets 18, 19, and 20, where the insulating gasket 18 in the illustrated example has a cylindrical shape and is aligned inside the through hole 15 of the first wall 8 of the container 3, the insulating gasket 19 in the illustrated example has a disk shape and is disposed on the outer surface of the first wall 8, and the insulating gasket 20 in the illustrated example has a disk shape and is disposed on the inner surface of the first wall 8.

[0060] As shown in FIG. 7, after the insulating gaskets 18, 19 and 20 are bonded to the first wall 8 of the container 3, a rivet 16 is placed through the hole 15 in the first wall 8 of the container 3, located on the outside of the container 3 (i.e. on the outside of the first wall 8 of the container 3), constituting the positive electrode 14 of the battery 1, and having a head 17 which compresses the insulating gasket 19 against the first wall 8 of the container 3. In this way, the head 17 is placed on the outer surface of the first wall 8 of the container 3. At this point, as shown in FIG. 8, the headless end of the rivet 16 is pressed (i.e. plastically deformed) to form a counter head 21 which compresses the insulating gasket 20 against the first wall 8 of the container 3, in particular against the inner surface of the first wall 8 opposite the aforementioned outer surface.

[0061] 9, an electrochemical cell 2 with a current collector 11 having (in the middle) a protrusion 23 (which in the illustrated case is cylindrical) is then inserted into the container 3, so that at the end of the insertion of the electrochemical cell 2, the protrusion 23 of the current collector 11 is inserted into the hole 22 of the rivet 16 and engages with the hole 22 itself. Once the insertion of the electrochemical cell 2 into the container 3 is complete, i.e. once the insertion of the protrusion 23 of the current collector 11 into the hole 22 of the rivet 16 is complete, a weld 24 is made that connects the rivet 16 to the protrusion 23 of the current collector 11 in order to establish both a good mechanical connection and a good electrical connection.

[0062] It is important to note that the weld 24, which in this case is annular, can be made from the outside of the vessel 3 and therefore without any kind of obstruction. As a result, the execution of the weld 24 can be completed quickly while still ensuring the achievement of a high overall quality.

[0063] Essentially, in the method according to the invention, the current collector 11 is (at least temporarily) placed in communication with the outside of the vessel (via the hole 15 ) so that the weld 24 can be made from the outside of the vessel 3 .

[0064] In the embodiment shown in Figures 2 to 9, the outer surface of the protrusion 23 of the current collector 11 is initially flush with the outer surface of the head 17 of the rivet 16. In other words, the outer surface of the protrusion 23 is initially flush with the outer surface of the head 17 of the rivet 16 once it is inserted into the hole 22 (when the protrusion 23 is inserted into the hole 22). In this embodiment, the hole 22 and the protrusion 23 of the rivet 16 have shapes (i.e., no flare) that are substantially complementary to each other (cylindrical in the illustrated case) (a shape coupling occurs between them). According to an alternative embodiment shown in Figures 10 and 11, the outer surface of the cylindrical protrusion 23 of the current collector 11 initially protrudes from the outer surface of the head 17 of the rivet 16, i.e., when the protrusion 23 is inserted into the hole 22, it protrudes from said outer surface. In this embodiment, the hole 22 of the rivet 16 has an outer flare. After the cylindrical protrusion 23 of the current collector 11 is inserted into the hole 22 of the rivet 16, the outer portion of the protrusion 23 is pressed into the head 17 of the rivet 16 by plastic deformation so as to make the outer surface of the protrusion 23 of the current collector 11 flush with the outer surface of the head 17 of the rivet 16.

[0065] According to a different embodiment shown in Fig. 13, the current collector 11 does not have a protrusion 23, and a weld 24 is made between the counter head 21 of the rivet 16 and the current collector 11 via a hole 22 in the rivet 16. According to a different embodiment shown in Fig. 14, the rivet 16 is replaced by a connecting element 25 (which in the illustrated case is a ring) having a through hole 26 (preferably in the center), in the illustrated case having a cylindrical shape penetrating across the connecting element 25. The hole 26 of the connecting element 25 engages with the protrusion 23 of the current collector 11. In particular, the hole 26 is arranged at least partially in alignment (preferably coaxially) with the hole 15 when the connecting element 25 is arranged on the outer surface of the first wall 8.

[0066] In this case, the access includes a hole 26 .

[0067] Between the connecting element 25 and the protrusion 23 of the current collector 11 is a weld 24 that provides both a stable mechanical connection between the connecting element 25 and the protrusion 23 of the current collector 11 and a low resistance electrical connection between the connecting element 25 and the protrusion 23 of the current collector 11. In this embodiment, the positive electrode 14 of the battery 1 consists of a connecting element 25 that replaces the head 17 of the rivet 16.

[0068] In the embodiment shown in FIG. 14 , the protrusion 23 of the current collector 11 is surrounded internally by a fixing element 27 (which in the illustrated case is a ring) whose function is to compress (and thus hold in place) the insulating gasket 20 against the inner surface of the first wall 8 of the container 3.

[0069] 15 and 16 show some steps of the realization of the embodiment shown in FIG. 14, making it possible to better see the structure of the connecting element 25 and the protrusion 23 of the current collector 11.

[0070] In the embodiment shown in Figs. 14-16, the outer surface of the protrusion 23 of the current collector 11 is initially flush with the outer surface of the connection element 25, i.e. flush when inserted into the hole 26. In this embodiment, the hole 26 of the connection element 25 has a shape (in this case cylindrical) that is substantially complementary to the protrusion 23 (i.e. without flaring) (a shape coupling is created). According to an alternative embodiment shown in Figs. 17 and 28, the outer surface of the protrusion 23 of the current collector 11 initially protrudes from the outer surface of the connection element 25, i.e. protrudes from it when the protrusion 23 is inserted into the hole 26. In this embodiment, the hole 26 of the connection element 25 has an outward flare. After inserting the protrusion 23 of the current collector 11 into the hole 26 of the connection element 25, the outer part of the protrusion 23 is pressed into the connection element 25 by plastic deformation so as to make the outer surface of the protrusion 23 of the current collector 11 flush with the outer surface of the connection element 25.

[0071] In the embodiment shown in Figures 1 to 18, hole 22 of rivet 16 or hole 26 of connecting element 25 are through holes, i.e. hole 22 passes across rivet 16 and hole 26 passes across connecting element 25, and thus protrusion 23 of current collector 11 is directly visible on the outside of container 3 (i.e. it is outside rivet 16 or connecting element 25).

[0072] According to a different embodiment shown in FIG. 22, the holes 26 in the outer connecting element 25 are absent.

[0073] In this situation, the weld 24 is made from outside the container 3 in "transparency", i.e. through the outer connection body 25, brought from the opposite side of the electrochemical cell 2 with respect to the wall 8. This weld 24 is made from the outside in "transparency" because the heat required to melt the metal at the top of the projection 23 of the current collector 11 is not supplied directly to the projection 23 of the current collector 11, but reaches the top of the projection 23 of the current collector 11 through the connection element 25 (which is sufficiently thin).

[0074] The thickness of the connecting element 25 is preferably comprised between 0.2 mm and 0.6 mm.

[0075] The weld 24 is preferably operated with a laser.

[0076] According to a different embodiment shown in figures 19 to 21, the holes 22 of the rivets 16 and the holes 26 of the connecting elements 25 are concealed since they have a (preferably thin) top wall that closes the holes 22 and 26 and hides from view the protrusions 23 of the current collector 11. In this case the protrusions 23 of the current collector 11 are not directly visible outside the container 3 since they are completely hidden by the rivets 16 or the connecting elements 25.

[0077] In other words, as shown in Figures 19 and 20, the hole 22 of the rivet 16 is blind (not a through hole) and therefore defines a recess (seat, cavity, housing) in which the protrusion 23 of the current collector 11 is located. The weld 24 must therefore pass across a portion of the head 17 of the rivet 16 to reach the protrusion 23 of the current collector 11 (as mentioned above, the weld 24 is made from the outside).

[0078] In the embodiment shown in FIG. 19, the head 17 of the rivet 16 is thinner at the protrusion 23 of the current collector 11 (i.e., at the weld 24 and at the hole 22), while in the embodiment shown in FIG. 20, the head 17 of the rivet 16 has a uniform thickness everywhere.

[0079] Preferably, in both cases the thickness is comprised between 0.2 mm and 0.6 mm.

[0080] Similarly, as shown in Fig. 21, the hole 26 of the connection element 25 is blind (not a through hole) and thus defines a recess (seat, cavity, housing) in which the protrusion 23 of the current collector 11 is placed. The weld 24 must therefore pass across a part of the connection element 25 to reach the protrusion 23 of the current collector 11 (as mentioned above, the weld 24 is made from the outside). In the embodiment shown in Fig. 21, the head 17 of the rivet 16 is thinner at the protrusion 23 of the current collector 11 (i.e. at the weld 24 and the hole 26).

[0081] As highlighted above, in the embodiment shown in Figures 19 to 22, the heat required to melt the metal at the top of the protrusion 23 of the current collector 11 is not supplied directly to the protrusion 23 of the current collector 11, but passes through the rivet 16 or connecting element 25, across them and reaches the top of the protrusion 23 of the current collector 11, so that the weld 24 is made from the outside in "transparency".

[0082] In the embodiments shown in the accompanying drawings, the battery 1 has a cylindrical shape, and therefore at least some of the components of the battery 1 (e.g. the electrochemical cell 2 and the container 3) have a cylindrical shape (or in any case a shape with cylindrical symmetry), while according to other embodiments not shown, the battery 1 has a shape other than a cylindrical shape (e.g. a parallelepiped shape), and therefore at least some of the components of the battery 1 (e.g. the electrochemical cell 2 and the container 3) have a shape other than a cylindrical shape (e.g. a parallelepiped shape). That is, the electrochemical cell 2 and the container 3 can have a prismatic shape with a circular base (and therefore can be cylindrical) or can have a prismatic shape with a rectangular or square base (and therefore can be rectangular prism shaped).

[0083] The head 17, which is arranged outside the container 3 (i.e. outside the first wall 8 of the container 3) and constitutes the positive electrode 14 of the battery 1, may have a cylindrical shape (as shown in the attached figure) or a shape other than a cylindrical shape (for example, a rectangular parallelepiped shape).

[0084] In a further embodiment, not shown, access to the current collector 11 to be welded is only made via the container 3, without affecting the outer body 17, 25. In this embodiment, the first wall 8 of the container 3 comprises a hole 15 for inserting the rivet 16 and a further through-hole into which the projection 23 of the current collector 11 is inserted, and the weld 24 is made (from the outside) between the head 17 and the projection 23 of the current collector 11.

[0085] Thus, the energy storage battery according to the previous embodiment includes an electrochemical cell 2, a current collector 11 coupled to one end of the electrochemical cell 2, a container 3 having a first wall 8 with a first through hole 15 and housing the electrochemical cell 2 therein such that the current collector 11 is positioned adjacent to the first wall 8, a rivet 16 inserted into the first hole 15, and a further through hole in the first wall 8 of the container 3 through which a protrusion 23 of the current collector 11 is inserted, and a weld 24 is made between a head 17 of the rivet 16 and the protrusion 23 of the current collector 11.

[0086] The embodiments described herein can be combined with one another without departing from the scope of protection of the present invention.

[0087] The manufacturing method and battery 1 described above have many advantages.

[0088] First, the manufacturing method and battery 1 described above allows for high production speeds (i.e., a large number of cylindrical vessels 3 produced per unit time) without spatial constraints on the dimensions and movement of the welding tool, since the annular weld 24 is made outside the vessel 3. This is possible by positioning the current collector 11 in (at least temporary) communication with the outside of the vessel 3 (through holes 15 and / or holes 22 / 26) such that the weld 24 can be made from outside the vessel 3.

[0089] The above-described manufacturing method and battery 1 also ensure a higher quality of the final product (i.e., fewer defects). This result is obtained thanks to the fact that the weld 24 is not made inside the container 3 (i.e., from the inside), but outside the container 3 (i.e., from the outside). In this way, metal debris accidentally formed while making the weld 24 does not enter the container 3, but remains outside the container 3 and thus cannot contaminate the cylindrical electrochemical cell 2. In other words, while making the annular weld 24, splashes of molten metal can occur that, by cooling, form small metal debris. However, since the weld 24 is made outside the container 3, such small debris cannot enter the container 3. The absence of metal debris generated by the weld 24 inside the container 3 makes it possible to substantially reduce the failure of the electrochemical cell 2. This is because, if these small metal debris were present, they could cause small local short circuits that could cause premature deterioration of the electrochemical cell 2 over time.

[0090] Furthermore, the thickness of the current collector 11 can be limited (in the embodiment shown in Figures 2 to 11) with the benefit of reducing the height of the battery 1 (i.e., the thickness of the current collector 11 does not have to be increased) since the current collector 11 does not have to withstand a breakthrough that may occur while making the weld 24, since the weld 24 does not directly affect the current collector 11 but affects the protrusion 23 of the current collector 11.

[0091] The fact that the rivet 16 has a through hole 22 (or that the connecting element 25 has a through hole 26) simplifies (speeds up) the insertion of the electrochemical cell 2 into the container 3, in that when the electrochemical cell 2 enters the container 3, the air present at the bottom of the container 3, which has been compressed by the advancement of the electrochemical cell 2, can be more effectively evacuated through the through hole 22 of the rivet 16, rather than being evacuated through the hole 5 of the electrochemical cell 2 (as would necessarily be the case if the through hole 22 of the rivet 16 were not present).

[0092] Finally, the manufacturing method and battery 1 described above are simple and cheap to implement, as they do not require complex machining or the use of specific (non-standard) materials. [Explanation of symbols]

[0093] 1 battery 2. Electrochemical Cell 3 containers 4 Longitudinal Axis 5 Through hole 6 side wall 7 First end 8 The First Wall 9 Second End 10 Lid 11 Current collector 12 Current collector 13 Negative electrode 14 Positive electrode 15 holes 16 Rivet 17 Head 18 Insulating gasket 19 Insulating gasket 20 Insulating gasket 21 Counterhead 22 holes 23 Protrusion 24 Welding 25 Connection Elements 26 holes 27 Fixed elements

Claims

1. A method for manufacturing an energy storage battery (1), comprising the steps of: Providing an at least partially completed electrochemical cell (2) provided with a current collector (11); Providing a container (3) having a first wall (8); placing, on the outer surface of said first wall (8), an outer body (17; 25) constituting an electrode (14) of said battery (1); inserting the electrochemical cell (2) into the container (3) so that the current collector (11) is close to the first wall (8); providing said current collector (11) with access (15; 22; 26) from outside the container (3) to allow a weld (24) between said current collector (11) and said outer body (17; 25); - welding said current collector (11) and said outer body (17; 25) together at said access (15; 22; 26) to establish an electrical connection; A manufacturing method comprising:

2. The method according to claim 1, wherein said access (15; 22; 26) comprises a first through hole (15) made in said first wall (8).

3. the access portion (15; 22; 26) comprises a second hole (22; 26) made in the outer body (17; 25) and at least partially aligned with the first hole (15) when the outer body (17; 25) is placed on the outer surface of the first wall (8), The method according to claim 2, wherein said weld (24) is made in said second hole (22; 26).

4. 4. The method according to claim 3, wherein the weld (24) is made from the outside of the container (3) through the second hole (22; 26) and brought from the opposite side of the electrochemical cell (2) relative to the first wall (8).

5. The method according to claim 3 or 4, wherein the weld (24) is located at least partially inside the second hole (22; 26).

6. 6. A method according to claim 3, 4 or 5, wherein the second bore (22; 26) is coaxial with the first bore (15) when the outer body (17; 25) is placed on the outer surface of the first wall (8).

7. The method according to any one of claims 3 to 6, wherein the second hole (22; 26) in the outer body (17; 25) is a through hole.

8. The method according to any one of claims 3 to 6, wherein the second holes (22; 26) of the outer body (17; 25) are blind and form recesses into which protrusions (23) of the current collector (11) are inserted.

9. the current collector (11) includes a protrusion (23) that is inserted into the first hole (15) of the first wall (8) and the second hole (22; 26) of the outer body (17; 25); The method according to any one of claims 3 to 8, wherein the weld (24) is made between the outer body (17; 25) and the protrusion (23) of the current collector (11).

10. 10. The method according to claim 9, wherein after inserting the protrusion (23) into the second hole (22; 26), an outer surface of the protrusion (23) is flush with an outer surface of the outer body (17; 25).

11. an outer surface of the protrusion (23) first protrudes beyond the outer surface of the outer body (17; 25) after the protrusion (23) is inserted into the second hole (22; 26); The second central bore (22) of the outer body (17; 25) has an outward flare.

10. The method of claim 9, further comprising the step of at least partially pressing an outer surface of the protrusion (23) against the outer body (17; 25) so as to make the outer surface of the protrusion (23) flush with an outer surface of the outer body (17; 25).

12. 12. The method according to claim 9, 10 or 11, wherein a rivet (16) is provided, the rivet (16) including a head (17) which engages with the first hole (15) in the first wall (8) and is arranged on the outside of the container (3) constituting the outer body (17; 25) and a counter head (21) which is arranged on the inside of the container (3).

13. 12. The method according to claim 11, wherein the rivet (16) initially only has the head (17), whereas the counter-head (21) is obtained after inserting the rivet (16) through the first hole (15) in the first wall (8) by forcing the rivet (16) into an inner surface of the first wall (8).

14. 12. The method according to claim 9, 10 or 11, wherein the outer body (17; 25) consists only of connecting elements (25) arranged completely outside the container (3).

15. 15. The method according to claim 14, wherein the projection (23) of the current collector (11) is surrounded at its base by a fixing element (27) having the function of compressing the insulating gasket (20) against the inner surface of the first wall (8).

16. The method according to any one of claims 3 to 7, wherein the current collector (11) has no protrusions and the weld (24) is made inside the second hole (22; 26) of the outer body (17; 25).

17. the current collector (11) includes a protrusion (23) that is inserted into the first hole (15) of the first wall (8); The method according to claim 1, wherein the weld (24) is made between the outer body (17; 25) and the protrusion (23) of the current collector (11).

18. placing a first insulating gasket (18) inside said access (15; 22; 26) to line said access (15); disposing a second insulating gasket (19) between the outer body (17; 25) and an outer surface of the first wall (8); disposing a third insulating gasket (20) between the inner surface of the first wall (8) and the current collector (11); The method of any one of claims 1 to 17, further comprising:

19. 3. The method according to claim 1 or 2, wherein the weld (24) is made through the outer body (17; 25) from outside the vessel (3), passing across the outer body (17; 25) and being brought from the opposite side of the electrochemical cell (2) to the first wall (8).

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