Manufacturing method, energy storage element, and lid assembly

Abstract

To provide a method for manufacturing an energy storage element, an energy storage element, and a lid assembly.SOLUTION: In the manufacture of the energy storage device 100, an electrode-separator assembly 104 having an anode-separator-cathode sequence with a first terminal end face 104a and a second terminal end face is provided, a contact sheet metal member 112 is applied to one of the end faces, a bridging sheet metal member 177 is secured to the contact sheet metal member, the electrode-separator assembly is inserted into a housing part having a terminal circular opening, the circular opening of the housing part 101 is closed by a lid 102 to form a closed housing, and the lid is welded to the contact sheet metal member or the bridging sheet metal member. The use of a lid having at least one hole 119 is provided. This allows pressure equalization between the two sides of the lid when it is welded.SELECTED DRAWING: Figure 11

Description

[Technical Field]

[0001] The invention described below relates to a manufacturing method, an energy storage element, and a lid assembly. [Background technology]

[0002] Electrochemical energy storage devices can convert stored chemical energy into electrical energy through oxidation-reduction reactions. The simplest form of an electrochemical energy storage device is an electrochemical cell. It contains a positive electrode and a negative electrode, with a separator between them. During discharge, electrons are released at the negative electrode as a result of an oxidation process. This results in an electronic current that can be drawn by an external electrical consumer, for which the electrochemical cell serves as an energy source. Simultaneously, an ionic current corresponding to the electrode reactions is generated within the cell. This ionic current passes through the separator and is enabled by the ion-conducting electrolyte. In this way, the separator prevents direct contact between the electrodes. However, at the same time, it allows electrical charge compensation between the electrodes.

[0003] If the discharge is reversible, i.e., the conversion of chemical energy generated during discharge to electrical energy can be reversed and the cell recharged, the cell is called a secondary cell. In a secondary cell, the designation of the negative electrode as the anode and the positive electrode as the cathode refers to the discharge function of the electrochemical cell.

[0004] An electrochemical energy storage element may include exactly one electrochemical energy storage cell, but it may also include two or more cells, which are preferably connected electrically in series or electrically in parallel.

[0005] Secondary lithium-ion cells are currently used as energy storage elements in many applications because they can supply high currents and are characterized by a relatively high energy density. They are based on the use of lithium, which can be transported back and forth between the electrodes of the cell in the form of ions. The negative and positive electrodes of lithium-ion cells are generally formed by so-called composite electrodes, which contain electrochemically active as well as electrochemically inactive components.

[0006] In principle, any material capable of absorbing and releasing lithium ions is suitable as the electrochemically active component (active material) of a secondary lithium-ion cell. For the negative electrode, carbon-based particles such as graphite carbon are used for this purpose. For the positive electrode, lithium cobalt oxide (LiCoO2), lithium manganese oxide (LiMn2O4), lithium iron phosphate (LiFePO4), or their derivatives can be used. The electrochemically active material is generally contained in the electrode in the form of particles.

[0007] As an electrochemically inactive component, a composite electrode generally comprises a flat and / or ribbon-shaped current collector, e.g., a metal foil, which serves as a carrier for the respective active materials. The current collector is generally coated with a thin film of the respective active material. The current collector for the negative electrode (anode current collector) can be made of, for example, copper or nickel, and the current collector for the positive electrode (cathode current collector) can be made of, for example, aluminum.

[0008] Additionally, as an electrochemically inactive component, the electrode may include an electrode binder (e.g., polyvinylidene fluoride (PVDF) or another polymer, such as carboxymethyl cellulose), conductivity-enhancing additives, and other additives. The electrode binder ensures the mechanical stability of the electrode and often also the adhesion of the active material to the current collector.

[0009] Lithium-ion cells typically contain a solution of a lithium salt, such as lithium hexafluorophosphate (LiPF6), in an organic solvent (e.g., carbonate ethers and esters) as the electrolyte.

[0010] Composite electrodes are typically combined with one or more separators to form an electrode-separator assembly during the manufacture of lithium-ion cells. The electrodes and separators are often, but not always, bonded together under pressure, possibly by lamination or the use of adhesives. The assembly can then be impregnated with electrolyte to establish basic cell functionality.

[0011] In many embodiments, the electrode-separator assembly is formed in the form of a winding or processed into a winding. In the first case, for example, a ribbon-shaped positive electrode, a ribbon-shaped negative electrode, and at least one ribbon-shaped separator are separately fed into a winding machine, where they are spirally wound into a winding in the order positive electrode / separator / negative electrode. In the second case, the ribbon-shaped positive electrode, the ribbon-shaped negative electrode, and at least one ribbon-shaped separator are first combined to form an electrode-separator assembly, for example, using pressure as described above. The assembly is then wound in a further step.

[0012] For applications in the automotive sector and other applications with high energy requirements, such as electric bicycles or power tools, lithium-ion cells with as high an energy density as possible are needed, which can simultaneously be subjected to high current loads during charging and discharging.

[0013] Cells for the above-mentioned applications are often designed as cylindrical cells with a form factor of, for example, 21 x 70 (diameter x height, in mm). This type of cell always includes an electrode-separator assembly in the form of a wire wound. Modern lithium-ion cells with this form factor can achieve energy densities of up to 270 Wh / kg.

[0014] Electrical contact of the electrodes of the energy storage element poses a challenge: for example, in a circular cell with a 21x70 form factor, the electrodes of the windings need to be electrically connected and coupled to the electrical poles of the respective housing.

[0015] A conventional solution here is the "tab design", where one end of a strip-shaped metal sheet (the "tab") is welded to an electrode, and the other end is connected to the functional components of, for example, a CID (current interrupt device) integrated into the multi-part lid of a metal housing. An example of this is described in US Pat. No. 5,649,499.

[0016] The function of a CID is known to those skilled in the art and ensures that the current flow in the energy storage element is interrupted in the event of a fault. Another safety feature is the so-called PRV (pressure relief valve), which opens if a defined pressure limit is exceeded and prevents a dangerous overpressure from building up in the energy storage element.

[0017] The tab design has several drawbacks. One problem is that the tab must be relatively long because it can only be welded to the inside of the lid before the housing is closed. Also, when the housing is closed, the tab must be folded at least once, which is often difficult to achieve in manufacturing. Additionally, the folded tab occupies space inside the housing that is no longer available for electrochemically active material, and the tab itself becomes a bottleneck not only in terms of current flow in and out of the housing, but also in terms of heat dissipation. During operation of the electrochemical cell, heat is generated at the electrodes, and this heat needs to be dissipated. This is difficult when the tab is the only heat escape route available.

[0018] In recent years, there has been an increase in research into lithium-ion cells in which the electrodes are contacted by a so-called "tableless design." This design completely eliminates the tabs. Instead, the electrode-separator assembly is fabricated in the form of a winding, in which the electrodes have metallic current collectors with uncoated longitudinal edges that protrude from the winding at their end faces. Metal contact sheet metal members can then be welded onto the longitudinal edges, as described, for example, in U.S. Pat. No. 5,623,499. This allows the current collectors, and therefore the associated electrodes, to be electrically contacted over their entire length. This significantly reduces the internal resistance within the cell. As a result, large currents can be absorbed much better and heat can be dissipated more effectively from the winding.

[0019] However, known variations of the "tabless design" do not solve all existing problems. For example, an electrical connection between the lid and the contacting sheet metal member is still required. A suitable conductor must be welded to the lid before closing the housing, and therefore must be the same length as the tabs mentioned above. As a result, when closing the housing, the conductor must be bent like the tab, creating a dead volume within the housing. [Prior art documents] [Patent documents]

[0020] [Patent Document 1] U.S. Patent No. 7,432,010B2 [Patent Document 2] International Publication No. 2017 / 215900A1 Brochure Summary of the Invention [Problem to be solved by the invention]

[0021] The object of the present invention was to provide an energy storage element characterized by a high energy density. At the same time, the energy storage element provided must meet the highest safety standards. This object is achieved by a method for manufacturing an energy storage element having the features of claim 1 and by an energy storage element having the features of claim 8. A lid assembly according to claim 9 is also the subject of the present invention. Preferred embodiments of the present invention are defined in the dependent claims 2 to 7 and 10. [Means for solving the problem]

[0022] The method according to the invention always comprises the following features: a. providing an electrode-separator assembly having an anode / separator / cathode sequence, the electrode-separator assembly having a first terminal end face and a second terminal end face; b. applying a contact sheet metal member to one of the end faces; c. In a preferred embodiment, Welding a bridging sheet metal member onto a contacting sheet metal member, or Fixing the bridging sheet metal member onto the contacting sheet metal member by forming an alternative material-locking or form-locking connection; d. Inserting the electrode-separator assembly into a housing portion, particularly a metal housing cup, having a terminal circular opening; e. closing the circular opening of the housing portion with a lid to form a closed housing, the lid having a first surface facing the interior of the housing after closing and a second surface facing the exterior; f. welding the lid to the contacting or bridging sheet metal member; It is characterized by:

[0023] Step b. is preferably carried out before step d. However, it is also possible to apply a contact sheet metal element to one of the end faces of the electrode-separator assembly (the one facing the opening) after the electrode-separator assembly has been inserted into the housing cup. In either case, after applying the contact sheet metal element, it is preferable to form a connection between the current collector protruding from this end face and the contact sheet metal element. For example, a material-locking connection can be formed by laser welding.

[0024] In many cases, after the electrode separator is inserted, one of the end faces of the electrode-separator assembly rests directly on the bottom of the housing part having the terminal circular opening. In this case, it may be necessary to connect the current collector protruding from this end face to the housing bottom. This can be done by welding through the housing bottom using a laser. In another possible embodiment, a suitable contact sheet metal member is applied to this end face before step d., so that after insertion, only this contact sheet metal member needs to contact the housing cup or its bottom, for example, by a welded connection. The welded connection between the contact sheet metal member and the bottom can be made, for example, by resistance welding.

[0025] Step c. is only necessary if the contact sheet metal members themselves do not include bridging regions (embodiments of contact sheet metal members with and without bridging regions are described below). Step c. can also be performed before or after step d., i.e., insertion of the electrode-separator assembly into the housing cup.

[0026] Conventional sealing methods can be used to close the circular opening with the lid. Sealing by flanging is preferred. In this process, the edge of the circular opening is bent radially inward while a seal disposed between the lid and the edge is compressed. The seal and lid can be fabricated as a pre-made lid component, with the seal fitted onto the edge of the lid.

[0027] In most cases, the seal compression is highest in the area between the recess and the lid, described below.

[0028] Closing the cell may also include a height calibration in which the lid is pressed towards the bottom of the housing cup, which can significantly reduce the height of the cell and therefore its internal volume.

[0029] The method according to the invention is in particular g. The lid has at least one hole It is characterized by:

[0030] The connection between the contact sheet metal elements and the bridging sheet metal elements can, if desired, be realized for example by a material-locking connection, in particular a welding or bonding or soldering connection. Riveting connections are also possible.

[0031] Bonding can be achieved by connecting the contact and bridging sheet metal members using an electrically conductive adhesive, such adhesives being known for example from printed circuit board technology.

[0032] The soldered connections may be formed by melting solder and allowing it to solidify in contact with the contacting and bridging sheet metal members.

[0033] The riveted connection may be achieved, for example, by means of blind rivets, in particular blind seal rivets, which are forced through holes in the contacting and bridging sheet metal members.

[0034] According to the invention, the lid is connected directly to the contacting sheet metal member or to the bridging sheet metal member that contacts the contacting sheet metal member, this is achieved by welding the lid as described above.

[0035] During welding, if a portion of the lid melts completely in a specific welding area, this can cause problems. When the housing is closed, a pressure different from the external pressure can build up inside the housing, for example, as a result of a reduction in the internal volume during height calibration, or if the housing is already filled with electrolyte, for example, as a result of electrolyte evaporation or a chemical reaction occurring due to the heat generated during welding. This can have a very negative impact on the welding process. In extreme cases, excessive pressure inside the housing can cause molten material from the lid to be expelled from the welding area.

[0036] At least one hole solves these problems by allowing pressure equalization between the two surfaces of the lid when the lid is welded. This is possible as long as at least one hole is not closed. A hole with a maximum diameter of 2000 μm, preferably 1000 μm, more preferably 500 μm, even more preferably 250 μm, and especially 100 μm is generally sufficient. The hole is preferably made by a punching process or drilled into the lid or its subcomponents.

[0037] It is also possible to create the holes using a laser beam. In certain embodiments, it is preferable to introduce electrolyte into the housing after step d. above, but before step e. above. It is preferable to close at least one hole before the cell begins operation. In either case, it is necessary to ensure a liquid-tight seal of the housing.

[0038] Preferably, the method is characterized by the following additional feature a. a. At least one hole is closed when the lid is welded. Alternatively, the holes may be closed after welding, for example by adhesive.

[0039] In a further preferred embodiment, the method is characterized by at least one of the following additional features a. and b.: a. The lid is welded using a laser. b. At least one hole is closed by a laser, in particular the laser used in step a.

[0040] Therefore, it is particularly preferred to close at least one hole with the same laser as that used to weld the lid. For example, the edge of the hole and the area of ​​the contact or bridging sheet metal element located below it can be melted by the laser. When the melt solidifies, a welded joint is formed between the lid and the contact or bridging sheet metal element. At the same time, the hole is closed.

[0041] In further preferred embodiments, the method is characterized by one of the following additional features a. to c.: a. The closed housing encloses an interior space in which the electrode-separator assembly is disposed. b. the lid includes a metal disk having a circular edge, the metal disk having an interior surface defining an interior space. c. The metal disc contains at least one hole. Features a. to c. are preferably implemented in combination with each other.

[0042] In a further preferred embodiment, the method is characterized by one of the following additional features a. and b.: a. The contact sheet metal member includes a connection area where it is connected to the inner surface of the metal disk. b. The bridging sheet metal member includes a connection area where it is connected to the inner surface of the metal disc. Features a. and b. are preferably implemented as alternatives to each other.

[0043] In a further preferred embodiment, the method is characterized by at least one of the following additional features a. and b.: a. The metal disc includes a connection region where it is welded to the connection region of the contacting sheet metal member or the connection region of the bridging sheet metal member. b. The connection region includes at least one hole. Preferably, the metal disc and the contacting sheet metal member or the metal disc and the bridging sheet metal member are fused together by welding in the connection area.

[0044] As explained below, the design described herein eliminates the need for a separate, long electrical conductor to electrically connect the lid and the contacting sheet metal members. The conductor function is performed by either the bridging sheet metal member or the contacting sheet metal member with the bridging region already mentioned, which bridges the gap between the lid and the electrode-separator assembly within the housing.

[0045] In addition, the welded connection between the lid and the contact sheet metal member or between the lid and the bridging sheet metal member can be formed after the housing has been closed, which has great advantages in terms of optimal utilisation of the available housing volume.

[0046] In a preferred embodiment, the lid always has the following features a. to d. immediately below: a. The lid is a lid assembly that includes, in addition to the metal disc, a pole cap that is in electrical contact with the metal disc. b. The pole cap rests directly on the metal disc. c. The pole cap and metal disc seal the intermediate space. d. The pole cap includes at least one opening through which the connection area of ​​the metal disc is accessible from outside the housing, in particular by a laser. It is particularly preferred that the immediately preceding features a. to d. be combined.

[0047] In lid-to-lid assembly designs, the opening in the pole cap ensures that the connection area is accessible from the outside, allowing welding to be performed by a laser.

[0048] In embodiments of the invention in which the contact sheet metal member performs the function of bridging the distance between the lid and the electrode-separator assembly, the method is preferably characterized by at least one of the following features a.-c. immediately below. a. The contact sheet metal member comprises a contact area, preferably a disk-shaped contact area, for example an annular disk-shaped contact area, to which the longitudinal edge of the anode current collector or its longitudinal edge is connected, in particular welded. b. The contact area is disposed circumferentially around the bridging area, preferably sealingly surrounding the bridging area. c. The bridging region projects from the plane of the contact region and extends to the connection region of the contacting sheet metal member where the contacting sheet metal member is connected to the inner surface of the metal disc.

[0049] The immediately preceding features a and b are preferably implemented in combination. The immediately preceding features a to c are particularly preferred when implemented in combination.

[0050] Therefore, in a preferred embodiment, the contact sheet metal element comprises a contact region, a bridging region and a connection region. The contact region preferably extends in a first plane and preferably lies flat on one end face. The bridging region extends from the plane of the contact region towards the connection region. The connection region preferably extends in a second plane and preferably lies flat inside the metal disk. The plane of the connection region is therefore preferably spaced axially from the plane of the contact region. It is particularly preferred that these two planes are aligned parallel to one another. The contact sheet metal element therefore preferably comprises two regions (contact region and connection region) in different planes.

[0051] As already mentioned above, the contact areas of the contact sheet metal members may be formed as annular disk-shaped contact areas. In other embodiments, the contact areas may include individual contact segments arranged around the bridging area and / or connected to one another via connecting areas. For example, the connecting area and the contact segments may be connected to one another via webs. These webs may form the bridging area. The contact segments may be, for example, ring segments.

[0052] In embodiments of the invention in which a bridging sheet metal member performs the function of bridging the distance between the lid and the electrode-separator assembly, the method is preferably characterized by at least one of the immediately following features a. to c.: a. the bridging sheet metal member comprises a contact area, in particular an annular disc-shaped contact area, which contact area is connected to the contacting sheet metal member, in particular by said welding; b. The contact region is disposed around the bridging region, and in a preferred embodiment, surrounds the bridging region. c. The bridging region projects from the plane of the contact region and extends to a connection region of the bridging sheet metal member where the bridging sheet metal member is connected to the inner surface of the metal disc.

[0053] Preferably, the immediately preceding features a and b are implemented in combination. It is particularly preferred to implement the immediately preceding features a to c in combination.

[0054] Therefore, in a preferred embodiment, the bridging sheet metal member comprises a contact region, a bridging region and a connection region. The contact region preferably extends in a first plane and preferably lies flat on the contacting sheet metal member. The bridging region protrudes from the plane of the contact region and extends to the connection region. The connection region preferably extends in a second plane and preferably lies flat inside the metal disk. The plane of the connection region is therefore preferably spaced axially from the plane of the contact region. It is particularly preferred that these two planes are aligned parallel to one another. The bridging sheet metal member therefore preferably comprises two regions (contact region and connection region) in different planes.

[0055] In addition to a ring-disc shape, the contact area of ​​the bridging sheet metal member can have other configurations. For example, it can be ring-shaped with a polygonal outer surface shape, such as an outer edge with six or eight corners. In other embodiments, the contact area can include individual contact segments arranged around the bridging region and / or interconnected via connection regions, as in the case of the contacting sheet metal members.

[0056] It should be mentioned here that, in principle, the metal disk of the lid can also serve to bridge the distance between the lid and the contact sheet metal element. For this purpose, the metal disk must include a bridging region in the connection area that is connected to the contact sheet metal element, preferably by welding or bonding. In this case, this bridging region protrudes axially and extends to the contact sheet metal element, which preferably rests on one of the end faces.

[0057] Preferably, the lid of the energy storage element according to the invention incorporates several safety features: a. The metal disc of the lid is preferably configured as a PRV (pressure relief valve) and includes an elongated weakened groove for this purpose. b. In the connection area, the metal disk is characterized by a thinner thickness of material than in the area surrounding the connection area.

[0058] The immediately preceding features a. and b. are particularly preferably combined, although they may also be implemented independently of each other.

[0059] The immediately preceding feature b. relates to the CID function of the lid, which will be explained below with reference to the drawings relating to the present invention.

[0060] Preferably, the elongated weakened groove extends circumferentially around the centre of the metal disc.

[0061] In either case, it should be noted that the energy storage element produced according to the present method is preferably an energy storage element having both PRV and CID functionality.

[0062] In a further preferred embodiment, the method is characterized by the following additional feature a. a. After step e. of claim 1, the formation of the energy storage element (100) is carried out.

[0063] As explained above, step e. refers to closing the circular opening of the housing portion with a lid to form a closed housing. As explained in the detailed description of the examples below, the present invention allows for the formation of an energy storage element having a housing already closed by a lid.

[0064] All energy storage elements that can be manufactured according to the above method are subject of the present invention. Preferably, the energy storage element according to the present invention has the following characteristics: a. the energy storage element includes an electrode-separator assembly having an anode / separator / cathode sequence; b. the electrode-separator assembly is in the form of a cylindrical winding having first and second terminal end faces and a winding shell therebetween; c. the anode of the electrode-separator assembly includes an anode current collector having a first longitudinal edge and a parallel second longitudinal edge, a main area loaded with a layer of negative electrode material, and a free edge strip extending along the first longitudinal edge and not loaded with negative electrode material; d. the cathode of the electrode-separator assembly includes a cathode current collector having a first longitudinal edge and a parallel second longitudinal edge, a main area loaded with a layer of positive electrode material, and a free edge strip extending along the first longitudinal edge and not loaded with electrode material; e. placing the anode and cathode within the electrode-separator assembly such that a first longitudinal edge of the anode current collector protrudes from the first end face and a first longitudinal edge of the cathode current collector protrudes from the second end face of the electrode-separator assembly; f. the energy storage element includes a contacting sheet metal member mounted on a first longitudinal edge of the anode current collector and covering a first terminal end face, or mounted on a first longitudinal edge of the cathode current collector and covering and connected to a second terminal end face; g. The energy storage element includes an airtight and liquidtight housing including a metal housing part having a terminal circular opening, in particular a metal housing cup having a terminal circular opening, and a lid having a circular edge that closes the circular opening, the airtight and liquidtight housing sealing an internal space in which the electrode-separator assembly is disposed; h. the lid includes a metal disk having a circular edge, the metal disk having an inner surface defining an interior space and an opposite outer surface; i. the contacting sheet metal member includes a bridging region that is connected to the inner surface of the metal disc at a connection region, or the bridging sheet metal member is welded onto the contacting sheet metal member, and the bridging sheet metal member includes a bridging region that is connected to the inner surface of the metal disc at a connection region; j. the metal disc includes a connection region where it is welded to the connection region of the bridging sheet metal member or the connection region of the contacting sheet metal member; k. In the connection area, the metal disc has a hole or at least a recess or a reduction in thickness in the area of ​​the weld. It is characterized by:

[0065] Many of the features of the energy storage element have already been mentioned in the description of the method according to the invention, please see the corresponding description.

[0066] The electrochemical energy storage element according to the present invention is preferably an electrochemical energy storage cell.

[0067] As already explained above, during welding, the laser can melt the edges of the hole, which allows pressure equalization, and the connection area of ​​the underlying contact or bridging sheet metal element. Depending on the welding parameters and / or the size of the hole, it is possible that only the edges of the hole are welded to the connection area of ​​the underlying contact or bridging sheet metal element, and the hole itself is not filled with melt. In this case, after the melt has solidified, a recess remains, especially on the outside of the metal disk. On the other hand, if the melt from the edges fills the hole, this generally results in a reduction in the thickness of the welded area.

[0068] To ensure a reliable liquid-tight and gas-tight seal, it may be preferable to fill the recesses on the outside of the metal disk with a sealant, for example, an adhesive. This is easily possible through a suitably designed opening in the lid, for example through the openings in the pole caps of the lid described below. Alternatively, welding can also be performed directly by fusion welding with a filler metal. In this case, the recesses resulting from the holes can be filled with the filler metal. This may also be a preferred approach to ensure a liquid-tight and gas-tight seal of the cell.

[0069] In some particularly preferred embodiments, the connection area of ​​the bridging sheet metal element or the connection area of ​​the contact sheet metal element is connected to the connection area of ​​the metal disc by welding in the form of a weld line surrounding the hole, in particular by a circular weld line. In this case, the hole itself may still be present after welding. In some preferred embodiments, it may be preferable to additionally seal the hole by filling it with the above-mentioned adhesive. The combination of the circular weld line surrounding the hole and the adhesive filling also ensures a liquid-tight and gas-tight seal.

[0070] With regard to the mechanical stability of the energy storage element produced and the aforementioned safety features, the following preferred features are also important: a. The housing includes a seal made of a plastic material attached to the edge of the lid and disposed between the lid and the housing portion having the terminal circular opening, the seal being preferably an annular seal. b. A support ring made of plastic material is arranged, in particular clamped, between the metal disc and the bridging sheet metal member or between the metal disc and the contacting sheet metal member. c. The support ring rests on the contact area of ​​the contacting sheet metal member or the contact area of ​​the bridging sheet metal member. d. The support ring is part of the seal.

[0071] The immediately preceding features a. to c. are particularly preferred, and in some particularly preferred embodiments, features a. to d. are also realized in combination.

[0072] In particularly preferred embodiments, the energy storage element is further characterized by the following features a. and b.: a. A housing portion having a terminal circular opening includes, in axial order, a bottom portion, a center portion, and a sealing portion; - the central portion is cylindrical, and at the central portion, the winding shell of the electrode-separator assembly contacts the inner surface of the housing portion having the terminal circular opening; and - in the sealing portion, the seal is pressed against the edge of the lid and against the inner surface of the housing portion having the terminal circular opening; and b. The housing portion having the terminal circular opening has an opening edge in the sealing portion that defines the circular opening, and the opening edge is bent radially inward over the edge of the lid to which the seal is attached, and the lid containing the seal is fixed in a shape-locking manner in the circular opening of the housing portion.

[0073] The electrode-separator assembly is preferably in direct contact with the inner surface of the housing part having the terminal circular opening. It is particularly preferred that the electrode-separator assembly be located directly on the inner surface. However, in some embodiments, it may be provided to electrically insulate the inner surface, for example, by a foil. In this case, the electrode-separator assembly contacts the inner wall via the foil.

[0074] The bottom of the housing part having the circular terminal opening preferably has a circular shape. The housing part is usually formed by deep drawing. However, it is also possible to form the housing part by welding the bottom having a circular shape to the tubular half.

[0075] The energy storage element according to the invention is preferably designed as a cylindrical cell. Its height is preferably in the range of 50 mm to 150 mm. Its diameter is preferably in the range of 15 mm to 60 mm. Cylindrical cells with these form factors are suitable, for example, for supplying power to the electric drive of a car.

[0076] Preferred Electrochemical Embodiments In a particularly preferred embodiment of the invention, the energy storage element according to the invention is based on lithium-ion technology.

[0077] Essentially, all electrode materials known for secondary lithium-ion cells can be used for the electrodes of the energy storage element.

[0078] The nominal capacity of the energy storage element according to the present invention, designed as a cylindrical cell based on lithium-ion technology, preferably reaches up to 15,000 mAh. In the case of a 21x70 form factor, the circular lithium-ion cell in one embodiment preferably has a nominal capacity in the range of 1,500 mAh to 7,000 mAh, particularly preferably in the range of 3,000 to 5,500 mAh. In the case of an 18x65 form factor, the circular lithium-ion cell in one embodiment preferably has a nominal capacity in the range of 1,000 mAh to 5,000 mAh, particularly preferably in the range of 2,000 to 4,000 mAh.

[0079] In further embodiments, the energy storage element may be a sodium-ion cell, a potassium-ion cell, a calcium-ion cell, a magnesium-ion cell, or an aluminum-ion cell. Of these variations, energy storage elements having sodium-ion cell chemistry are particularly preferred.

[0080] In energy storage elements based on sodium-ion technology, it is particularly preferred that both the anode and cathode current collectors consist of aluminum or an aluminum alloy. The housing and contact sheet metal members and, where applicable, the bridging sheet metal members may also consist of aluminum or an aluminum alloy.

[0081] Preferred housing design The energy storage element according to the invention is particularly preferred in that it has at least one of the following characteristics a. to c.: a. The central portion and the sealing portion are separated by a recess circumferentially surrounding the outer surface of the housing portion having the terminal circular opening. b. The housing part having the terminal circular opening has the same maximum outer diameter at the center and sealing part. c. In the region of the recess, the reduction in the outer diameter of the housing part carrying the terminal circular opening preferably corresponds to 4 to 20 times the wall thickness of the housing part carrying the terminal circular opening in this region.

[0082] It is preferable that at least the immediately preceding features a and b be realized in combination. It is particularly preferable that all three of the immediately preceding features a to c be realized in combination.

[0083] Preferably the annular seal is compressed at the sealing portion, preferably it is pressed radially against the circular edge of the lid.

[0084] The lid assembly according to the invention is preferably characterized by the following features a. to g.: a. The lid assembly includes a metal disc and pole cap that are in electrical and direct mechanical contact with each other. b. The pole cap rests directly on the metal disc. c. The pole cap and metal disc seal the intermediate space. d. The metal disc includes the above-mentioned connection area, where it can be welded to the connection area of ​​the contacting sheet metal member or to the connection area of ​​the bridging sheet metal member. e. The pole cap includes at least one opening through which the connection area is accessible from outside the housing, in particular by a laser. f. The lid assembly includes a seal fitted over its edge. g. The connection region includes at least one hole.

[0085] Some parts of the lid assembly have already been described in the description of the method according to the invention, please refer to these descriptions.

[0086] The at least one hole preferably is or comprises a hole having a minimum diameter of 0.01 mm and a maximum diameter of 1 mm.

[0087] Preferred embodiments of contacting and bridging sheet metal members The contact sheet metal member may be electrically connected to either the anode current collector or the cathode current collector.

[0088] In a particularly preferred embodiment of the present invention, the contact sheet metal member electrically connected to the anode current collector is characterized by at least one of the following features a. and b.: a. The contact sheet metal elements consist of nickel, copper, titanium, or alloys of nickel, copper, or titanium, or stainless steel, for example 1.4303, 1.4404, or SUS304 type, or nickel-plated copper. b. The contact sheet metal member is made of the same material as the anode current collector.

[0089] In a further particularly preferred embodiment of the present invention, the contact sheet metal member electrically connected to the cathode current collector is characterized by at least one of the following features a. and b.: a. The contact sheet metal members are made of aluminum or aluminum alloy. b. The contact sheet metal member is made of the same material as the anode current collector.

[0090] The bridging sheet metal member is preferably made of the same material as the contacting sheet metal member to which it is welded.

[0091] The contact sheet metal member connected to the anode current collector and / or the contact sheet metal member electrically connected to the cathode current collector are particularly preferred if they have at least one of the following characteristics a. and b.: a. The contact sheet metal members preferably have a uniform thickness in the range of 50 μm to 600 μm, preferably in the range of 150 μm to 350 μm. b. The contact sheet metal member is dimensioned so as to cover at least 40%, preferably at least 70%, particularly preferably at least 80% of the first or second terminal end face on which it rests.

[0092] It is particularly preferred that the immediately preceding features a. and b. are realized in combination with each other.

[0093] The bridging sheet metal member preferably consists of a sheet having a thickness in the range of 50 μm to 1 mm.

[0094] For thermal management of the energy storage element according to the present invention, it is important to cover as much of the end face area as possible. The greater the coverage, the easier it is to contact as much of the first longitudinal edge of each current collector as possible. Therefore, heat generated in the electrode-separator assembly can be better dissipated through the contacting sheet metal members.

[0095] In some embodiments, it has been found to be advantageous to subject the longitudinal edges of the current collector to a pre-treatment before the contact sheet metal member is placed thereon.

[0096] The longitudinal edges of the current collector may be subjected to directional deformation by pre-treatment, for example, they may be bent in a defined direction. Additionally, the longitudinal edges of the current collector may also be deformed in a non-directional manner, for example, as a result of pressure contact with a contact sheet metal member.

[0097] Preferred designs for current collectors and separators The anode current collector, cathode current collector and separator(s) of a cell according to the invention preferably have the following dimensions: - Lengths ranging from 0.5m to 25m - Width ranges from 40mm to 145mm

[0098] In an electrode-separator assembly, the ribbon anode, ribbon cathode, and one or more ribbon separators are preferably spirally wound. To manufacture an electrode-separator assembly, the ribbon electrode and one or more ribbon separators are typically fed to a winding device and preferably spirally wound around a winding axis. Bonding or contact at elevated temperatures between the electrode and separator is typically not required. In some embodiments, the electrode and one or more separators are placed on a winding mandrel and wound onto a cylindrical or hollow cylindrical winding core that remains within the winding after winding.

[0099] The winding shell can be formed, for example, by a plastic film or adhesive tape. It is also possible for the winding shell to be formed by one or more separator windings.

[0100] The current collector of the energy storage element according to the present invention has the function of electrically contacting the electrochemically active components contained in each electrode material over as large an area as possible, and is preferably made of metal or metallized at least on its surface.

[0101] In the case of an energy storage element according to the invention configured as a lithium-ion cell, suitable metals for the anode current collector are, for example, copper or nickel or other electrically conductive materials, in particular alloys of copper and nickel or nickel-coated metals.

[0102] In the case of an energy storage element according to the invention designed as a lithium-ion cell, aluminum or other electrically conductive materials, including aluminum alloys, are particularly suitable as metals for the cathode current collector.

[0103] The anode current collector and / or the cathode current collector is preferably a ribbon-shaped metal foil having a thickness in the range of 4 μm to 30 μm.

[0104] However, in addition to foils, other ribbon-like substrates such as metal or metallized nonwoven fabrics, or open-pore metal foams, or expanded metals may also be used as current collectors.

[0105] The current collector is preferably loaded on both sides with the respective electrode material.

[0106] The longitudinal edges of one or more separators preferably form the end faces of an electrode-separator assembly formed as a winding.

[0107] Possible seal designs The energy storage element according to the invention is preferably characterized by at least one of the following features a. and b.: a. The seal is made of a plastic material having a melting point above 200°C, preferably above 300°C, particularly preferably above 300°C and below 350°C. b. The plastic material is polyether ether ketone (PEEK), polyimide (PI), polyphenylene sulfide (PPS), polytetrafluoroethylene (PTFE), polybutylene terephthalate (PBT), or ethylene propylene diene rubber (EPDM). The immediately preceding features a. and b. are preferably implemented in combination.

[0108] Further features and advantages of the invention are apparent from the following description of preferred embodiments of the invention in conjunction with the claims and the drawings, in which the features shown can be implemented alone or in combination with other features. The drawings are presented diagrammatically. [Brief explanation of the drawings]

[0109] [Figure 1] 1 shows a cross-sectional view of a first embodiment of an energy storage cell according to the present invention having a lid assembly and a bridging sheet metal member according to the present invention; [Figure 2] 2 shows a cross-sectional view of a second embodiment of an energy storage cell according to the present invention. [Figure 3] 1 shows a cross-sectional view of a third embodiment of an energy storage cell according to the present invention. [Figure 4] 1 shows a partial cross-sectional view of a first embodiment of an energy storage cell according to the present invention; [Figure 5] 1 is a depiction of a preferred embodiment of a lid assembly according to the present invention. [Figure 6] 1 is a diagram of a preferred embodiment of a bridging sheet metal member suitable for an energy storage cell according to the present invention; FIG. [Figure 7] 1 is a diagram of a preferred embodiment of a contact sheet metal member suitable for an energy storage cell according to the present invention; [Figure 8] 1 illustrates an electrode-separator assembly and its components that may be part of an energy storage cell according to the present invention. [Figure 9] 1 shows a view (cross-section) of the bottom area of ​​an energy storage cell according to the invention. [Figure 10] 1 shows a cross-sectional view of a fourth embodiment of an energy storage cell according to the present invention. [Figure 11] 1 shows a cross-sectional view of a fifth embodiment of an energy storage cell according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0110] The energy storage cell 100 shown in FIG. 1 includes an electrode-separator assembly 104 in the form of a cylindrical winding having two terminal end faces and a winding shell located therebetween. A first longitudinal edge 106a of the anode current collector 106 protrudes from the terminal end face 104a. This edge is not free from the electrode material but is connected by welding to a contact sheet metal member 112, which rests on the longitudinal edge 106a and covers the first terminal end face 104a.

[0111] The energy storage cell 100 further includes an airtight and liquidtight housing having a metal housing cup 101 with a terminal circular opening and a lid assembly 102 with a circular edge 102a that closes the circular opening. The lid assembly 102 includes a metal disk 113 whose bottom surface 113b also matches the first surface 102b of the lid 102, which defines the interior space 140 of the housing, and a pole cap 117 that rests directly on the metal disk 113, is in electrical contact with it, and seals the intermediate space therewith. The second surface 102c of the lid 102 matches the outer surface of the pole cap 117 and faces outward.

[0112] A bridging sheet metal member 177 is welded onto the contacting sheet metal member 112. The bridging sheet metal member 177 includes a contact region 177c, a bridging region 177a, and a connecting region 177b.

[0113] The contact area 177c extends in a first plane and lies flat on the contact sheet metal member 112 and is fixed thereto, preferably by welding. The contact area 177c is formed as an annular disk-shaped contact area and surrounds the bridging area 177a.

[0114] The bridging region 177a rises dome-shaped from the plane of the contact region 177c and extends axially to the connection region 177b. The connection region 177b extends in a second plane spaced apart from the first plane, and its top surface is flat and lies flat against the bottom surface 113b of the metal disk 113. Thus, the plane of the connection region 177b is axially spaced apart from the plane of the contact region 177c. In this embodiment, these two planes are aligned parallel to each other. Thus, the bridging sheet metal member 177 includes two regions (the contact region 177c and the connection region 113a) in different planes.

[0115] The connection area 177b is bounded by an annular groove 178. The connection area 177b is connected to the connection area 113a of the metal disk 113 by a circular weld seam 120. However, instead of the circular weld seam 120, a spot weld connection, in particular a weld connection with several spot welds, is also conceivable.

[0116] The metal disk 113 comprises in its center a connection area 113a, where a circular weld is realized with connection area 177b. The metal disk 113 is formed as a PRV (pressure relief valve) and comprises a circular elongated weakened groove 199 for this purpose. In the center of connection area 113a there is again a hole 119, which is circumferentially surrounded by a weld seam 120. It may be advantageous to additionally seal hole 119 with adhesive.

[0117] Pole cap 117 includes several openings, including hole 117a, through which the laser can access connection area 113a from outside the housing.

[0118] The housing further includes a plastic seal 103 that fits over the edge 102a of the lid assembly 102 and electrically insulates the metal components of the lid assembly 102 from the housing cup 101. At the same time, this facilitates sealing the housing.

[0119] The energy storage cell 100 further includes a support ring 189 clamped between the metal disk 113 and the bridging sheet metal member 177. The support ring 189 rests on the contact area 177c of the bridging sheet metal member 177 and presses against the metal disk 113 from below. In this embodiment, the support ring 189 is part of the seal 103.

[0120] This embodiment of the energy storage cell 100 according to the present invention has various advantages: The lid assembly 102 according to the present invention consists of only three parts: (from outside to inside) the pole cap 117, the metal disc 113 and the seal 103. In comparison, conventional lid assemblies with equivalent functionality generally include at least four parts. The design of the lid assembly 102 is simplified. - Bridging sheet metal member 177 replaces the "tab" mentioned at the beginning.

[0121] The resulting simplified construction allows the bridging sheet metal member 177 to be welded to the metal disc 113 after the housing is closed. As shown, all that is required is a hole 117a in the pole cap 117. The welding can be performed from the outside using a laser.

[0122] - Welding is facilitated by holes 119 that allow pressure equalization between the interior space of the housing and the housing environment. Unless the connection areas 113a and 177b are connected to each other by a circular weld line 120, these areas will not hermetically seal the cell if holes 119 are present to allow pressure equalization until the weld line is completed (the contact between the two flat connection areas 113a and 177b still allows sufficient gas passage due to small irregularities such as surface or shape deviations of the components).

[0123] However, this can also be advantageously used in other ways. As those skilled in the art know, before an electrochemical cell is first used, it must undergo a so-called formation process. This refers to the process of initially charging and discharging the cell to cause electrochemical activation of the cell components. This process often results in gassing of the cell, for example as a result of electrolyte decomposition. Therefore, formation is often performed before the cell is actually closed, because otherwise a critical pressure would build up within the cell. Here, the hole 119 makes it possible to form the cell even if the housing is already closed with the lid assembly 102. If gas is generated, pressure equalization can be performed at any time via the hole 119. After formation, the cell can be hermetically sealed, for example by closing the hole 119 during the described welding process or by forming the described weld seam around the hole 119, and optionally, the above-mentioned adhesive is additionally applied to seal the hole 119.

[0124] It should be noted that the welded connection between the connection regions 113a and 177b does not necessarily have to be formed as a circular line, and it is also possible to melt the edges of the hole 119 and the edges of the connection region 177b over a larger area.

[0125] The energy storage cell 100 is characterized by two safety features: a PRV (Pressure Relief Valve) and the aforementioned CID. The PRV is realized by a groove 199. When the pressure inside the housing exceeds a predefined limit, the metal disc 113 bursts along the groove 199.

[0126] - A circular groove 178 surrounding the center of the connection area 177b ensures the CID function. When the pressure inside the housing increases, the metal disk 113 expands outward. Due to the welded connection between the metal disk 113 and the bridging sheet metal member 177 at the connection area 177b, the expanded membrane exerts a tensile force on the connection area 177b. When this force is strong enough, the connection area 177b is torn off from the bridging sheet metal member 177 along the groove 178. As a result, the direct contact and electrical connection between the metal disk 113 and the bridging sheet metal member 177 is interrupted. An opening remains in the upper part of the bridging sheet metal member 177.

[0127] Another important aspect: the above-mentioned tensile forces risk causing the entire bridging sheet metal member 177 to lift up together with the metal disc 113, thereby causing failure of the CID. To avoid such a situation, the seal may include a support ring 189. If the metal disc 113 expands outwards, the support ring holds the bridging sheet metal member 177 in place and ensures that the CID functions.

[0128] The energy storage cell 100 shown in FIG. 2 differs from that shown in FIG. 1 only in that the support ring 189 is not formed as part of the seal 102.

[0129] The energy storage cell 100 shown in Figure 3 differs from that shown in Figure 1 in that the support ring 189 is not formed as part of the seal 102. A further difference is that the edge 177d of the contact area 177c is bent upward by 90 degrees.

[0130] FIG. 4 is a partial cross-sectional view of the embodiment of the energy storage cell according to the present invention shown in FIG.

[0131] 5 includes a pole cap 117, a metal disc 113, an annular seal 103, and a support ring 116. The metal disc 113 is in direct contact with the pole cap 117. The annular seal 103 is mounted on the circular edge of the lid assembly 102. The edge of the lid assembly is therefore formed by the edge of the metal disc 113 folded in a U-shape around the edge of the pole cap 117.

[0132] The pole cap 117 has a central hole 117a as an opening. The center of the metal disk 113 is located below this hole. In the center of the metal disk 113 is a connection area 113a, characterized by a reduced material thickness compared to the surrounding areas. Again, the hole 119 is located in the center of the connection area 113a. The lid assembly is shown in an unassembled state.

[0133] 6 shows a bridging sheet metal member 177 that can be used in the present invention. It includes an annular contact area 177c that can be connected to the contact sheet metal member 112 by welding. The contact area 177c surrounds a bridging area 177a, which rises dome-like from the plane of the contact area 177c. The bridging area 177a is formed by three webs 177g that bridge the axial distance between the contact area 177c and the connecting area 177b. Three openings 177f are located between the webs, which can serve for the passage of electrolyte and pressure equalization. Recesses 177e also serve the same purpose.

[0134] 7 shows a contact sheet metal member 112 that can be used in connection with the present invention. It includes a disk-shaped contact area 112c intended to be welded to the longitudinal edge 106a of the anode current collector 106 or the longitudinal edge 109a of the cathode current collector 109. Preferably, the contact area 112c extends essentially in a first plane. A bridging area 112d rises from the plane of the contact area 112c. The bridging area 112d includes three webs 112f connecting the contact area 112c to a circular connecting area 112e, which has a flat surface. The connecting area 112c preferably extends in a second plane axially spaced from the plane of the contact area 112c.

[0135] In the contact area 112c, there are three beads 166 in a star configuration, in the area of ​​these beads 166 a weld can be made with one of the longitudinal edges.

[0136] In energy storage cells such as those shown in FIGS. 1-4, bridging is often required because components such as the electrode-separator assembly 104 cannot always be manufactured with exactly the same dimensions, e.g., exactly the same height. Instead, processing-related deviations arise that need to be compensated for. The contact sheet metal member 112 contacts the electrode-separator assembly, or more precisely, the longitudinal edges protruding from the end faces of the assembly, while simultaneously allowing for axial tolerance compensation within the cell. In the illustrated embodiment, the bridging region 112d has a spring function and can act as a spring pressing downward against the electrode-separator assembly and upward against the lid. During the calibration described above, this spring effect can have a particularly compensating effect.

[0137] 8 shows the structure of an electrode-separator assembly 104 that may be part of an energy storage cell according to the present invention. The assembly 104 includes a ribbon-shaped anode 105 having a ribbon-shaped anode current collector 106, the ribbon-shaped anode current collector 106 having a first longitudinal edge 106a and a parallel second longitudinal edge 106b. The anode current collector 106 is a copper or nickel foil. It includes a ribbon-shaped main area loaded with a layer of anode material 107 and a free edge strip 106b extending along the first longitudinal edge 106a and not loaded with the anode material 107. The assembly 104 further includes a ribbon-shaped cathode 108 having a ribbon-shaped cathode current collector 109 having a first longitudinal edge 109a and a parallel second longitudinal edge. The cathode current collector 109 is an aluminum foil. It includes a ribbon-shaped main region loaded with a layer of cathode material 110 and a free edge strip 109b extending along the first longitudinal edge 109a and free of the cathode material 110. Both electrodes are shown individually in an unwound state.

[0138] The anode 105 and cathode 108 are offset from one another within the electrode-separator assembly 104 such that a first longitudinal edge 106a of the anode current collector 106 protrudes from a first terminal end face 104a of the electrode-separator assembly 104, and a first longitudinal edge 109a of the cathode current collector 109 protrudes from a second terminal end face 104b of the electrode-separator assembly 104. This offset arrangement is shown in the lower left of the figure, which also shows two ribbon-like separators 156 and 157 that separate the electrodes 105 and 108 from one another in the windings.

[0139] The bottom right figure shows the electrode-separator assembly 104 in a wound form, as can be used in one of the energy storage cells of Figures 1-4. The electrode edges 106a and 109a protruding from the end faces 104a and 104b are clearly visible. The winding shell 104c is formed by a plastic film. Figure 9 shows the bottom region of a preferred embodiment of an energy storage cell 100 according to the present invention. The electrode-separator assembly 104 is placed in the housing cup 101. A contact sheet metal member 132 rests on the bottom 101a of the housing cup. Its bottom side is preferably connected to the bottom 101a by welding. The welding can be achieved by a laser through the bottom 101a. Alternatively, at least one welding electrode can be guided, for example, through the axial cavity 150 in the center of the electrode-separator assembly 104. A counter electrode is pressed against the outer surface of the bottom 101a. The upper surface of the contact sheet metal member 132 is in direct contact with the longitudinal edge 109a of the anode current collector. Preferably, the longitudinal edge 109a and the contact sheet metal member 132 are also connected by welding.

[0140] The contact sheet metal member 132 is shown separately. Like the contact sheet metal member 112, it has a bead to improve contact with the longitudinal edge 109a. The slotted openings serve for venting and better distribution of the electrolyte.

[0141] The embodiment of the energy storage cell according to the present invention shown in FIG. 10 differs from the energy storage cells shown in FIGS. 1-4 in that the contact sheet metal member 112 includes a bridging region 112d. It further includes a connection region 112e connected to the inner surface of the metal disk 113. Therefore, the embodiment of the energy storage cell shown here does not include a separate bridging sheet metal member welded onto the contact sheet metal member. The contact sheet metal member 112 itself performs the function of the bridging sheet metal member. This has obvious advantages. Electrical contact of the electrode-separator assembly is achieved through only two metal components, namely the metal disk 113 and the contact sheet metal member 112, from the pole cap, which can function as a contact pole for tapping the voltage of the energy storage cell.

[0142] The contact sheet metal member 112 rests on the upper end face of the wound electrode-separator assembly 104 at its contact region 112c and is connected, ideally by welding, to a current collector protruding from this end face. The contact sheet metal member 112 may be formed in the same or similar manner as the contact sheet metal member shown in Figure 7. The contact region 112c rises dome-shaped from the plane of the contact region 112c and surrounds a bridging region 112d that extends to a connection region 112e, which lies directly adjacent to the connection region 113a of the metal disk 113. The contact sheet metal member 112 therefore preferably includes two regions (the contact region 112c and the connection region 112e) in different planes and axially spaced from each other.

[0143] The metal disk 113 and the contact sheet metal member 112 are welded together at the connection areas 112e and 113a. As in the energy storage cell of FIG. 1, grooves 199 and 178 ensure PRV and CID functions. The latter is supported by a support ring 189. The support ring 189 rests on the contact area 112c and is located between the contact area 112c and the edge area of ​​the metal disk 113. If the center of the metal disk 113 expands upward as a result of pressure generated within the housing, the contact area 112c is fixed onto the end face of the winding 104 by the support ring 189 and cannot lift off. This ensures that, when sufficient pressure is applied, the connection area 112e will be blown off, thereby interrupting the flow of current.

[0144] Notably, the illustrated cell has a housing cup 101 characterized by an increased thickness at the seal. Below the transition 101e, the housing cup is thinner than at the top. This is because, depending on the sealing technology, higher mechanical strength may be required at the seal than in the center, thereby saving housing material.

[0145] The metal disk 113 has a hole 119 in the connection region 113a, through which pressure equalization between the interior of the housing and the housing environment can occur. The diameter of this hole is approximately 50 μm. As explained above, this can serve to produce a welded connection between the connection regions, here in the form of a weld line 120. The hole 119 can be closed after or during the creation of the welded connection. However, it can remain open and be surrounded by the weld line 120, as shown here.

[0146] The energy storage cell 100 shown in FIG. 11 differs from that shown in FIG. 1 only in that the hole 119 is positioned off-center in the metal disk 113. Instead, it is positioned laterally offset next to the connection area 113a. Therefore, it cannot be sealed by welding the connection area 113a to the connection area 112e or the connection area 177b. The sealing must be performed in a separate step. For example, bonding, soldering, or welding are possible, which can be performed through one of the openings in the pole cap 117. The position of the opening in the pole cap 117 can be changed as needed for this purpose.

Claims

1. A method for manufacturing an energy storage element (100), comprising the steps of: a. providing an electrode-separator assembly (104) having an anode (105) / separator (156) / cathode (108) sequence, the electrode-separator assembly (104) having a first terminal end face (104a) and a second terminal end face (104b); b. applying a contact sheet metal member (112) to one of said end faces (104a, 104b); c. In a preferred embodiment, welding a bridging sheet metal member (177) onto said contacting sheet metal member (112); or - fixing a bridging sheet metal member (177) to said contacting sheet metal member (112) by forming an alternative material-locking or form-locking connection; d. Inserting said electrode-separator assembly (104) into a housing part (101), in particular a metal housing cup, having a terminal circular opening; e. Closing the circular opening of the housing part (101) with a lid (102) to form a closed housing, the lid (102) having a first surface (102b) facing the interior of the housing after closure and a second surface (102c) facing the exterior; f. Welding the lid (102) to the contacting sheet metal member (112) or the bridging sheet metal member (177). In a method comprising: g. The method, wherein the lid (102) has at least one hole (119) that allows for pressure equalization between the two sides of the lid (102) when the lid (102) is welded.

2. Additional features include: a. When the lid (102) is welded, the at least one hole (119) is closed.

2. The method of claim 1, comprising:

3. Additional features include: a. the lid (102) is welded using a laser; b. said at least one hole (119) is closed by a laser, in particular by said laser The method according to claim 1 or 2, comprising at least one of the following:

4. Additional features include: a. the closed housing enclosing an interior space in which the electrode-separator assembly (104) is disposed; b. the lid (102) includes a metal disk (113) having a circular edge, the metal disk (113) having an inner surface that defines the interior space; c. said metal disc (113) containing said at least one hole (119); The method according to any one of claims 1 to 3, comprising at least one of:

5. Additional features include: a. the contact sheet metal member (112) includes a connection region (112e) where it is connected to the inner surface of the metal disc (113); b. said bridging sheet metal member (177) including a connection region (177b) where it is connected to said inner surface of said metal disc (113); The method of claim 4 , comprising one of:

6. Additional features include: a. the metal disc (113) includes a connection region (113a) where it is welded to the connection region (112e) of the contacting sheet metal member (112) or the connection region (177b) of the bridging sheet metal member (177); b. said connection region (113a) including said at least one hole (119); The method of claim 5 , comprising at least one of:

7. Additional features include: a. The lid (102) is a lid assembly including, in addition to the metal disc (113), a pole cap (117) that is in electrical contact with the metal disc (113); b. The pole cap (117) is placed directly on the metal disc (113); c) the pole cap (117) and the metal disc (113) seal the intermediate space; d. The pole cap (117) includes at least one opening (117a) through which the connection area (113a) is accessible from outside the housing, in particular by a laser. The method according to claim 5 or 6, comprising at least one of the following:

8. An energy storage element (100) manufactured according to the method of any one of claims 1 to 7, characterized in that: a. the energy storage element includes an electrode-separator assembly (104) having the following order: anode (105) / separator (156) / cathode (108); b. The electrode-separator assembly (104) is in the form of a cylindrical winding having a first terminal end face (104a) and a second terminal end face (104b) and a winding shell (104c) located therebetween; c) the anode (105) of the electrode-separator assembly (104) comprises an anode current collector (106) having a first longitudinal edge (106a) and a parallel second longitudinal edge (106a), a main area loaded with a layer of negative electrode material (107), and a free edge strip extending along the first longitudinal edge (106a) and not loaded with negative electrode material; d. the cathode (108) of the electrode-separator assembly (104) comprises a cathode current collector (109) having a first longitudinal edge (109a) and a parallel second longitudinal edge (109a), a main area loaded with a layer of positive electrode material (110), and a free edge strip extending along the first longitudinal edge (109a) and not loaded with the electrode material (110); e. the anode (105) and the cathode (108) are disposed within the electrode-separator assembly (104) such that the first longitudinal edge (106a) of the anode current collector (106) protrudes from the first terminal end face (104a) and the first longitudinal edge (109a) of the cathode current collector (108) protrudes from the second terminal end face (104b) of the electrode-separator assembly (104); f. the energy storage element is a contact sheet metal member (112); resting on the first longitudinal edge (106a) of the anode current collector (106) and covering the first terminal end face (104a); or a contact sheet metal member (112) mounted on the first longitudinal edge (109a) of the cathode current collector (108) and covering the second terminal end face (104b); g. the energy storage element comprises an airtight and liquidtight housing including a metal housing cup (101) having a circular opening (101a) at a terminal end thereof and a lid (102) having a circular edge (102a) closing the circular opening, the airtight and liquidtight housing enclosing an interior space in which the electrode-separator assembly (104) is disposed; h. the lid (102) includes a metal disk (113) having a circular edge, the metal disk (113) having an inner surface defining the interior space and an opposite outer surface; i. the contact sheet metal member (112) includes a bridging region (112d) connected to the inner surface of the metal disc (113) at a connection region (112e), or a bridging sheet metal member (177) is welded onto the contacting sheet metal member (112), the bridging sheet metal member (177) comprising a bridging region (177a) connected to the inner surface of the metal disc (113) at a connection region (177b); j) said metal disc (113) includes a connection region (113a) which is connected to said connection region (112e) or said connection region (177b) by a weld (120); k. In the connection area (113a), the metal disk (113) has a hole (119) or at least a recess or a reduction in thickness in the area of ​​the weld (120). An energy storage element (100) characterized by:

9. 10. A lid assembly (112) for manufacturing an energy storage element according to claim 8, comprising: a. said lid assembly includes a metal disc (113) and a pole cap (117) in electrical and direct mechanical contact with each other; b. The pole cap (117) is placed directly on the metal disc (113); c) the pole cap (117) and the metal disc (113) seal the intermediate space; d. the pole cap (117) includes at least one opening (117a) through which the connection area (113a) is accessible from outside the housing, in particular by a laser; e. the lid assembly includes a seal (103) mounted on the edge thereof; f. said connection region (113a) including at least one hole (119); A lid assembly (112) having:

10. Additional features include: a. said at least one hole (119) is or includes a hole having a minimum diameter of 0.01 mm and a maximum diameter of 1 mm; The lid assembly of claim 9, comprising:

11. Additional features include: a. After step e. of claim 1, the formation of an energy storage element (100) is carried out. The method according to any one of claims 1 to 7, comprising:

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