Energy storage element and method for manufacturing an energy storage element

Abstract

The present invention provides an energy storage element that increases capacity and performance, and a method for manufacturing the same. [Solution] An energy storage element 100 having a metal housing cup 104 and a cover assembly 108 that closes the housing cup, comprising an electrode-separator complex 114 provided in the form of a cylindrical wound body 136 within the housing cup, and a contact plate portion 142 connected to a projection 141a of the anode current collector 118 or to a projection of the cathode current collector, wherein the housing cup is formed without a tool engagement structure.

Description

Technical Field

[0001] The present invention relates to a) a housing defining a longitudinal axis and an interior of an energy storage element, the housing having a metallic housing cup and a cover assembly closing the housing cup; b) a sealing configuration having a seal body radially enclosing and sealing the cover assembly with respect to the housing cup, the seal body being compressed against the cover assembly by a free end section of the housing cup bent radially inwards; c) an electrode-separator composite accommodated in the housing cup and provided in the form of a cylindrical winding body, having a sequence of anode / separator / cathode / separator; [[ID=B]] c1) The anode has an anode current collector having a band-shaped main area covered by a layer made of a negative electrode material, and having a free edge strip that is not covered by the electrode material and has a first longitudinal edge of the anode current collector, the free edge strip emerging from a first terminal end face of the electrode-separator composite and forming a protrusion at the first end face; c2) The cathode has a cathode current collector having a band-shaped main area covered by a layer made of a positive electrode material, and having a free edge strip that is not covered by the electrode material and has a first longitudinal edge of the cathode current collector, the free edge strip emerging from a second terminal end face of the electrode-separator composite and forming a protrusion at the second end face, the electrode-separator composite; d) a contact plate portion, d1) seating on the protrusion of the anode current collector, covering and being connected to the first terminal end face of the electrode-separator composite, or d2) seating on the protrusion of the cathode current collector, covering and being connected to the second terminal end face of the electrode-separator composite, the contact plate portion; This relates to an energy storage element having the following characteristics.

[0002] In addition, the present invention provides: (A) A step of providing a housing having a metal housing cup and cover assembly, (B) A sealing configuration having a sealing body, and a step of providing a support ring, (C) Steps of providing an electrode-separator complex, (D) Connect the contact plate portion to the edge strip of the anode collector or the edge strip of the cathode collector, especially by welding, step and (E) A step of positioning the sealant and the support ring, (F) Steps to connect the cover assembly to the contact plate portion, (G) Step of closing the housing cup, This also relates to the manufacture of such energy storage elements having [the specified characteristic]. [Background technology]

[0003] The type of energy storage element mentioned in the opening section is described, for example, in the applicant's (Patent Document 1).

[0004] Electrochemical energy storage elements have the ability to convert stored chemical energy into electrical energy through oxidation-reduction reactions. The simplest form of an electrochemical energy storage element is an electrochemical cell (hereinafter also referred to as an energy storage cell). It has positive and negative electrodes, which are connected to each other via an ion-conducting electrolyte. A separator can be placed between the electrodes for electrical insulation. During discharge, electrons are released at the negative electrode through an oxidation process. This results in an electrical current, which can be utilized by an external electricity consumer using the electrochemical cell as an energy supply device. Simultaneously, an ion flow corresponding to the electrode reaction is generated through the ion-conducting electrolyte within the cell.

[0005] An energy storage element can have multiple single electrochemical cells, for example, two or more energy storage cells connected to each other in parallel or series. Such an energy storage element with multiple cells is also called a battery.

[0006] Therefore, if the described discharge is reversible, there is a possibility of reversing the conversion from chemical energy to electrical energy generated during the discharge and recharging the cell; this is called a secondary cell. In the case of a secondary cell, the notation of the negative electrode as the anode and the positive electrode as the cathode, which is common, refers to the discharge function of the electrochemical cell.

[0007] Secondary lithium-ion cells are currently used in many applications as energy storage elements because they can provide high current and are distinguished by their relatively high energy density. They are based on the use of lithium, which can reciprocate between the electrodes of the cell in the form of ions. The negative and positive electrodes of a lithium-ion cell are generally formed by so-called composite electrodes, which have both electrochemically active and electrochemically inactive components.

[0008] When considering electrochemically active components (active materials) for secondary lithium-ion cells, the materials generally include all materials capable of absorbing and re-releasing lithium ions. For this purpose, carbon-based particles, such as graphite-like carbon, are used for the negative electrode. For example, lithium cobalt oxide (LiCoO2), lithium manganese oxide (LiMn2O4), lithium iron phosphate (LiFePO4), or derivatives thereof can be used as active materials for the positive electrode. Electrochemically active materials are generally contained in particle form within the electrode.

[0009] As electrochemically inert components, composite electrodes generally have planar and / or band-shaped current collectors, such as metal foil, which are used as carriers for the individual active materials. The current collector for the negative electrode (anode current collector) can be made from, for example, copper or nickel, and the current collector for the positive electrode (cathode current collector) can be made from, for example, aluminum.

[0010] Furthermore, the electrode may have an electrode binder (e.g., polyvinylidene fluoride (PVDF), or another polymer such as carboxymethylcellulose), conductivity-improving additives, and other additives as electrochemically inert components. The electrode binder ensures the mechanical stability of the electrode and often also ensures the adhesion of the active material on the current collector.

[0011] Lithium-ion cells typically contain a solution of a lithium salt, such as lithium hexafluorophosphate (LiPF6), in an organic solvent (such as carbonate ethers and esters) as an electrolyte.

[0012] Composite electrodes are generally combined with one or more separators to form an electrode-separator composite during the manufacture of lithium-ion cells. In this case, the electrodes and separators are often, though not essential, connected to each other under pressure, possibly by lamination or adhesive bonding. The basic functional capabilities of the cell can then be generated by impregnating the composite with an electrolyte.

[0013] In many embodiments, and in the present invention, the electrode-separator composite is formed in the form of a wound body or is processed to form a wound body. In the first case, for example, a band-shaped positive electrode and a band-shaped negative electrode, and at least one band-shaped separator are supplied separately to a winding device and wound spirally inside to form a wound body having the sequence positive electrode / separator / negative electrode. In the second case, the band-shaped positive electrode and the band-shaped negative electrode, and at least one band-shaped separator are first combined to form an electrode-separator composite, for example, by applying the pressure mentioned. Then, in a further step, the composite is wound.

[0014] For example, lithium-ion cells with the highest possible energy density are required for applications in the automotive sector, such as e-bikes, or for other applications with high energy demands, such as power tools, and these cells must simultaneously possess the ability to be utilized by high currents during charging and discharging.

[0015] Energy storage cells having electrode-separator complexes in the form of wound bodies for the applications mentioned are formed as cylindrical, round cells, which often have a length or height of 50 mm to 150 mm and a diameter ranging from 15 mm to 60 mm. For example, a recent lithium-ion cell with a form factor of 21 × 70 (diameter × height in mm) can achieve an energy density of up to 270 Wh / kg.

[0016] The internal volume ratio of a housing that can be used for a winding is particularly important in relation to the capacity and performance of an energy storage cell. Assuming the dimensions and components of the energy storage cell remain constant except for the winding, if a relatively large winding is configured in a corresponding manner within a relatively large volume, then a larger volume results in higher capacity and performance.

Prior Art Documents

Patent Documents

[0017]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0018] It is an object of the present invention to provide an energy storage element, particularly an energy storage cell considering this concept, and a method adapted thereto. This object is achieved e) in that the protrusion connected to the contact plate portion is a protrusion axially compressed, f) in that the housing cup is formed without a tool engagement structure, in the case of the energy storage element. <00​​​​​​​​​​​​​- In the central section, the electrode-separator composite, formed as a cylindrical wound body, is in contact with the inner side of the housing cup. - The end sections of the housing cup, which are folded radially inward, define a circular opening. - More preferably, a cover assembly including a ring-shaped seal is secured in a snug manner by end sections that are radially bent inward at the circular opening of the housing cup.

[0021] In the construction of the energy storage element mentioned in the introductory section, a conventional flanging method is used, in particular, to close the housing cup using a cover assembly. The initially cylindrical free end section of the housing cup is folded radially inward over the area of ​​the cover assembly, and the seal is compressed. Further details regarding this will be described below.

[0022] The winding body is already positioned within the housing cup in this case. In addition to the above, a tool engagement structure is generated within the housing cup in the known energy storage element to prevent damage to the winding body during the flanging method. The tool engagement structure has the function of allowing a portion of the flanging tool to be applied to the housing when the housing cup is closed by the flanging method. When the housing cup is closed, the opposing tool engages within the tool engagement structure as part of the flanging tool, for example, supporting the housing cup in the axial direction against the forces acting during the flanging method in the context of the opposing procedure, and dissipating these forces, so that the winding body remains substantially free from the action of the forces. A perfectly circumferential bead is usually provided within the housing cup for this purpose at the time of closure, and this bead remains even after the fabrication of the energy storage element.

[0023] Because this bead protrudes radially into the housing in relation to the other walls of the housing cup, the area where the bead is formed is not available for the winding body because it completely fills the housing cup radially.

[0024] The bending on the edge strip is described in the applicant's (Patent Document 2), for example, with the objective that the radius of the contact plate portion may be perceptibly smaller than the diameter of the winding body in order to reduce the risk that the contact plate portion will come into contact with the housing.

[0025] Furthermore, it is recognized in accordance with the present invention that the winding body to which the edge strip is connected to the contact plate portion may be bent or compressed in the axial direction, tightened or otherwise deformed, and generally, a winding body having a protruding portion compressed in the axial direction may be loaded by the force generated when the housing cup is closed without impeding any adverse effect on the function of the energy storage element. Moreover, it is recognized that no further support is required to resist the force generated when closing, and a tool engagement structure may be omitted.

[0026] As a result, the space is free in the axial direction for an energy storage element, particularly an energy storage cell, so that the main areas of the anode and cathode can be equipped with a winding that has a relatively large axial extension, while the other components have constant internal dimensions. Since these main areas support electrode material, this directly increases the capacity and performance of the energy storage element.

[0027] In preferred embodiments, band-shaped separators are used for the electrode-separator composite, and these separators are somewhat wider than the wound electrode. The longitudinal edges of these separators are preferably located within a single plane and preferably form the end face of the wound.

[0028] It is even more preferable that the free edge strip of the current collector emerging from the end face of the winding or the side of the lamination protrudes by 5500 μm or less, preferably 4000 μm or less, from the end face or side in an undeformed state, i.e., before axial compression of the protrusion. Therefore, the height of the protrusion of the free edge strip is preferably a maximum of 5500 μm, particularly preferably a maximum of 4000 μm, before axial compression. This applies especially to cells of format 21700 (21 mm diameter, 70 mm height).

[0029] The free edge strip of the anode current collector protrudes from the end face of the winding by a maximum of 3000 μm, and more preferably 2000 μm, before axial compression of the protrusion. The free edge strip of the cathode current collector protrudes from the end face of the winding by a maximum of 4000 μm, and more preferably 3000 μm, before axial compression. Therefore, the height of the protrusion of the free edge strip of the anode current collector is preferably a maximum of 3000 μm, and more preferably 2000 μm, before axial compression. Therefore, the height of the protrusion of the free edge strip of the cathode current collector is preferably a maximum of 4000 μm, and more preferably 3000 μm, before axial compression.

[0030] In the electrode separator winding used within the scope of the present invention, it is preferable that the protruding portion of the free edge strip emerging from the first terminal end face of the electrode-separator composite is compressed axially by at least 10% and a maximum of 80%, preferably 15% to 60%, and particularly preferably 15% to 50%, (relative to the height of the protruding portion before compression).

[0031] Furthermore, in the electrode separator winding used within the scope of the present invention, it is preferable that the protruding portion of the free edge strip emerging from the second terminal end face of the electrode-separator composite is compressed axially by at least 10% and a maximum of 80%, preferably 15% to 60%, and particularly preferably 15% to 50%, (relative to the height of the protruding portion before compression).

[0032] Therefore, a protrusion with an uncompressed height of 3 mm can still have a height of, for example, 1.6 mm after compression.

[0033] Within a composite body formed as a wound structure, a band-shaped anode, a band-shaped cathode, and one or more band-shaped separators are preferably provided wound in a spiral shape. To manufacture the composite body, the band-shaped electrodes are supplied to a winding device together with one or more band-shaped separators, and are preferably wound spirally inside the winding body around a winding axis. In some embodiments, the electrodes and one or more separators are wound on a cylindrical or hollow cylindrical winding core for this purpose, which sits on a winding mandrel and remains inside the wound structure after winding.

[0034] In this case, the tool engagement structure is defined as a structure within the side wall of the housing cup that allows the portion of the flanging tool to engage within it, for the purpose of performing the flanging procedure, and more particularly for the purpose of performing the counter-procedure. For this purpose, the structure must have a minimum depth within the side wall.

[0035] Such tool engagement structures used for flanging procedures can consist of ring-shaped indentations on the sidewall, particularly in the form of the bead mentioned. However, it is also conceivable that multiple indentations arranged in a ring shape within the sidewall, such as 3, 4, 6, or 8 indentations, may be used as tool engagement structures.

[0036] Conversely, this means that indentations within the sidewall that have a corresponding minimum depth are not included in the definition of the term tool engagement structure.

[0037] Accordingly, the scope of protection of the present invention as of applicable claim 1 is extended to energy storage elements in which the sidewalls of the housing cup do not have indentations. Furthermore, this is extended to energy storage elements in which the sidewalls of the housing cup have ring-shaped indentations formed as beads or multiple indentations configured in a ring shape having less than the minimum depth.

[0038] This minimum depth required for the flanging procedure is provided under the following conditions:

[0039] The depth of the ring-shaped indentation or the multiple indentations formed in a link shape as a tool engagement structure is preferably at least seven times the wall thickness of the housing cup within the area of ​​one or more indentations.

[0040] Conversely, this means that indentations having a depth of less than seven times the wall thickness of the housing cup within the area of ​​one or more indentations are, by definition, not tool engagement structures in the sense of this application. More preferably, indentations having a depth of less than six times the wall thickness of the housing cup within the area of ​​one or more indentations, preferably less than five times, even more preferably less than four times, even more preferably less than three times, and particularly preferably less than two times, are not tool engagement structures in the sense of this application.

[0041] Furthermore, perhaps regardless of the depth of this indentation, the tool tendency structure must always be functionally designed to collaborate with the engaging tools in the manner described above.

[0042] Closure techniques that can result in indentations of such small depth are described in (Patent Document 3). After insertion of the electrode-separator complex into the housing cup provided with the step, the step can be converted into a circumferential indentation by calibration of the outer diameter of the housing cup. This indentation extends in a ring shape around the side wall of the housing cup, but does not have the depth required for indentations used for flanging.

[0043] The cover assembly preferably defines a closure plane, which is generally established by a portion of the inner side of the cover assembly facing inward toward the housing. The smaller the axial distance between the main areas of the anode and cathode and the closure plane, the longer the main area having the wound electrode material can be installed while maintaining the same outer dimensions of the housing. In the energy storage element according to the present invention, an axial distance of 0.6 mm to 3.0 mm, particularly 0.8 mm to 2.5 mm, preferably 1.0 mm to 2.0 mm, and preferably 1.2 mm to 1.6 mm can be achieved between the main areas of the anode and cathode and the closure plane.

[0044] Furthermore, the cover assembly preferably has a circumferentially outer closure ring sealed by a sealant, and the closure plane is defined by the inner side portion of the closure ring facing inward toward the interior of the housing.

[0045] In a particularly preferred embodiment, the cover assembly has a metal disc, the metal disc is welded to the distance equalization structure within the connection area of ​​the distance equalization structure, and the distance equalization structure is a) Provided by a distance equalization plane portion connected to a contact plate portion, b) Provided by the contact plate portion.

[0046] Therefore, in the latter case, the contact plate portion has a distance equalization structure. As a result, a separate distance equalization structure is not required.

[0047] The reverse is also true: the distance equalization plate portion can have a contact area, which functions as a contact plate portion and is connected to the free edge strip of the anode current collector or the free edge strip of the cathode current collector.

[0048] The metal disk can provide a CID function (CID = current interruption device), which will be described in more detail later.

[0049] Energy storage elements are particularly preferably distinguished by at least one of the following characteristics: a) A support ring is provided between the distance equalization plate portion and the metal disk, which is either a separate component or constitutes a seal, and the support ring is in direct contact with the distance equalization plate portion and the metal disk. b) The seal has a support section, and by using it, the seal is supported on the contact plate portion or on the area of ​​the distance equalization plate portion.

[0050] The support ring or support section serves a fixing function, and in particular, it prevents the distance equalization plate portion and / or contact plate portion from rising together with the metal disk in the case of increased pressure within the housing, which is required in relation to the CID function mentioned.

[0051] For the purpose of providing CID functionality, the distance equalization structure may have flanking, or possibly material weakening, in particular grooves, located on the sides of the connection area of ​​the distance equalization structure or, if applicable, defining it.

[0052] In addition, the metal disc is designed as a PRV (pressure relief valve), and for this purpose, it may be advantageous to have material weakening features, such as weakening grooves in the form of a ring or circular ring. The PVR will be described in more detail below.

[0053] The above objectives are achieved in the method through the following steps. (H) In particular, compress or fold the edge strip in the axial direction before or during the execution of step (D). (I) Steps (D), (E), and (F), and (H) are performed on the outside of the housing cup so that a cover winding composite is formed. (K) Before performing step (G), introduce the cover winding composite and seal into the housing cup.

[0054] According to the present invention, it has been recognized that by eliminating the tool engagement structure, it is advantageous to allow the cover winding complex to be pre-finished as an assembly and then introduced only into the housing cup.

[0055] In relation to the CID function and the deformation of the distance equalization structure, here, (L) The distance equalization structure is provided by a distance equalization plate portion, and in step (F), the cover assembly is connected to the distance equalization structure, and the distance equalization plate portion is connected to the contact plate portion, or (M) The distance equalization structure is provided by a contact plate portion, and in step (F), it is advantageous that the cover assembly is connected to the distance equalization structure. The following describes in more detail an exemplary embodiment of the present invention based on the drawings. The drawings are as follows. [Brief explanation of the drawing]

[0056] [Figure 1] The image shows a longitudinal cross-section through a conventional energy storage cell, which has a housing with a tool engagement structure in the form of a circumferential tool engagement bead. [Figure 2] This shows an electrode-separator complex and its components. [Figure 3] Figure 1 shows a longitudinal cross-section corresponding to Figure 1, through an energy storage cell according to the present invention, having a housing without a tool engagement structure according to an embodiment for a first example. [Figure 4] Figure 3 shows a longitudinal cross-section through an energy storage cell according to the present invention, having a variation of the embodiment shown for illustrative purposes. [Figure 5] A longitudinal cross-section corresponding to Figure 1, through an energy storage cell according to the present invention, is shown, according to a second exemplary embodiment. [Figure 6] A longitudinal cross-section corresponding to Figure 1, through an energy storage cell according to the present invention, is shown, according to a third exemplary embodiment. [Figure 7] A longitudinal cross-section corresponding to Figure 1, through an energy storage cell according to the present invention, is shown, according to a fourth exemplary embodiment. [Modes for carrying out the invention]

[0057] 1. Conventional energy storage cells Figure 1 shows, for example, an example of an energy storage element in the form of an energy storage cell 10 having the basic structure disclosed in the applicant's above-mentioned (Patent Document 1).

[0058] The energy storage cell 10 has a housing 102, which is closed in an airtight and liquid-tight state, defining the boundary of the interior 102a and defining the longitudinal axis 10a of the energy storage cell 10. The housing 102 has a metal housing cup 104, which has a terminal circular opening 106. The housing cup 104 has, in the axial direction, a base 104a, a cylindrical central section 104b, and a closure section 104c.

[0059] In addition, the housing 102 has a cover assembly 108, which is located within the closure section 104c and closes the opening 106. The cover assembly 108 has a circumferential outer closure ring 110, which extends in a direction transverse to the longitudinal axis 10a of the energy storage cell 10. The energy storage cell 10 further has a sealing configuration having a ring-shaped seal 112 made of an electrically insulating material, which radially seals the cover assembly 108 and the seal relative to the housing cup 104. In the embodiment for this example, the seal 112 seals the closure ring 110 of the cover assembly 108 and electrically insulates the housing cup 104 and the cover assembly 108 from each other.

[0060] The closure plane 108a of the cover assembly 108 is bounded by the inner side portion 110a of the closure ring 110 of the cover assembly 108, which faces toward the interior 102a of the housing 102.

[0061] The energy storage cell 10 has an electrode-separator complex 114, which is housed within a housing cup 104, the structure of which is shown in Figure 2.

[0062] The electrode-separator complex 114 has a band-shaped anode 116 with a band-shaped anode collector 118, which has a first longitudinal edge 118a and a second longitudinal edge 118b parallel thereto. The anode collector 118 is a foil made of copper or nickel. The anode collector 118 has a band-shaped main area 120 covered by a layer made of negative electrode material 122, and a free edge strip 124 having the first longitudinal edge 118a of the anode collector 118 and not covered by the negative electrode material 122.

[0063] Furthermore, the electrode-separator complex 114 has a band-shaped cathode 126 with a band-shaped cathode current collector 128, which has a first longitudinal edge 128a and a second longitudinal edge 128b parallel thereto. The cathode current collector 128 is aluminum foil. The cathode current collector 128 has a band-shaped main area 130 covered by a layer made of positive electrode material 132, and a free edge strip 134 having the first longitudinal edge 128a of the cathode current collector 128 and not covered by the positive electrode material 132.

[0064] Figures 2A and 2B show the anode 116 and cathode 126 individually in their unwound state, respectively. Figure 2C shows the electrode-separator complex 114 in the form of a wound body 136, which can be used within an energy storage cell 10, where the anode 116 and cathode 126 are wound. The wound body 136 further has first and second band-shaped separators 138 and 140, which separate the anode 116 and cathode 126 from each other within the wound body. As a result, in this embodiment for illustrative purposes, the wound body 136 is consequently formed by a repeating sequence of anode 116 / separator 138 / cathode 126 / separator 140, the sequence starting with the anode 116 or cathode 126 depending on the outer layer. The wound body jacket 136a is formed of a plastic film.

[0065] Separators 138 and 140 can be observed in Figure 2D, which further shows that the anode 116 and cathode 126 are configured to be offset relative to each other inside the winding body 136, such that the free edge strip 124 emerges from the first terminal end face 114a together with the first longitudinal edge 118a of the anode collector 118, and the free edge strip 134 emerges from the second terminal end face 114b of the electrode-separator complex 114 together with the first longitudinal edge 128a of the cathode collector 128.

[0066] As a result, the free edge strip 124 of the anode collector 118 forms a projection 141a on the first end face 114a of the electrode-separator complex 114. Correspondingly, the free edge strip 134 of the cathode collector 128 forms a projection 141b on the second end face 114b of the electrode-separator complex 114. Both projections are shown here in their uncompressed state.

[0067] Therefore, these end faces 114a and 114b are also the corresponding end faces of the winding body 136. Figure 2C shows the winding body 136 and its components within its winding body configuration, in particular the edge strip 124 of the anode collector 118 and the edge strip 134 of the cathode collector 128, and thus the projections 141a and 141b formed by the free edge strips 124 and 134, which protrude freely in the axial direction and in relation to the winding body 136 when no force is applied.

[0068] In the energy storage cell 10, the cathode current collector 128 of the winding 134 is preferably welded directly to the base 104a of the housing cup 104 by its free edge strip 134 over its entire length. In other embodiments, the edge strip 134 can be welded to a metal plate which sits flat on the edge strip and is consequently electrically connected to the base 104, for example, by welding.

[0069] The anode collector 118 of the winding body 134 is connected to the contact plate portion 142 by welding along with its free edge strip 124, the contact plate portion 142 seating on the free edge strip 124 with a ring-shaped contact area 142a, in particular with the first longitudinal edge 128a of the anode collector 118, and covering the first terminal end face 114a of the electrode-separator complex 114 or the winding body 136.

[0070] Furthermore, in one variation, the installation of the winding body 136 can also occur in reverse using this method. In this case, the anode collector 118 is welded to the base 104a of the housing cup 104 by its free edge strip 124, while the cathode collector 128 is connected to the contact plate portion 142.

[0071] The cover assembly 108 of the energy storage cell 10 has an externally accessible polar hat 144, which is conductively connected to a metal disk 146 formed complementary thereto via an outer ring area 144a and seated on its upper surface, with an intermediate space 148 existing between the polar hat 144 and the metal disk 146. In the embodiment for illustrative purposes described herein, the outer edge area 146a of the metal disk 146 is folded outward around the ring area 144a of the polar hat 144, thereby forming a closure ring 110 of the cover assembly 108. The metal disk 146 defines the boundary of the interior 102a of the housing 102, and thus defines an outer side portion 150a facing away from the interior 102a and an inner side portion 150b facing toward the interior 102a.

[0072] The metal disc 146 is further designed as a PRV (pressure relief valve) and for this purpose has a ring-shaped material weakening, which in the embodiment for this example is formed by a circular elongated weakening groove 146b. When the pressure inside the housing 102 exceeds a predetermined limit, the metal disc 146 tears open along the groove 146b.

[0073] A distance equalization plate portion 152, having a ring-shaped contact area 152a used for welding the distance equalization plate portion 152 onto a contact plate portion 142, is positioned between the metal disc 146 of the cover assembly 108 and the contact plate portion 142 on the winding body 134. The ring-shaped contact area 152a merges radially inward into the distance equalization structure 154, and the distance equalization structure 154 extends outward from the plane of the contact area 152a in a dome shape in the direction of the metal disc 146. The distance equalization structure 154 is welded to the inner side portion 146b of the metal disc 146 within a connection area 154a, and the metal disc 146 is directly stationary within this connection area 154a. The connection area 154a of the distance equalization plate portion 152 is bounded by a groove 156 in the form of a ring or circular ring, which encloses the connection area 154a.

[0074] This groove 156 within the distance equalization structure 154 is an example of material weakening, located on the side of the connection area 154a, ensuring a so-called CID function (current interruption device). When the internal pressure of the housing 102 increases, the metal disk 146 bulges outward. Due to the welded connection between the metal disk 146 and the distance equalization structure 154, the bulging membrane exerts tension on the distance equalization structure 154 of the distance equalization plate portion 152. When this force is sufficiently strong, its connection area 154a is torn away from the distance equalization structure 154 along the groove 156. Thus, direct contact and electrical connection between the metal disk 146 and the distance equalization plate portion 152 are interrupted, and the hole remains within the upper portion of the distance equalization structure 154.

[0075] Furthermore, the distance equalization plate portion 152 and the contact plate portion 142 can also be replaced by a single component that performs the functions of both elements. Thus, for example, it would be possible to remove the contact plate portion 142 while directly welding the contact area 152a onto the edge strip 124. This also applies, in principle, to cells according to the present invention, particularly those described later.

[0076] The polar hat 144 has, in addition to further openings not otherwise indicated, a through hole 144b through which the metal disk 146 and the distance equalization plate portion 152 can be welded to each other from the outside, the metal disk 146 is accessible from the outside of the housing 102 to the connection area 154a of the distance equalization plate portion 152 for the laser within an overlap area.

[0077] In addition, the energy storage cell 10 has a support ring 158, which is clamped between the metal disk 142 and the distance equalization plate portion 152. The support ring 158 rests on the ring-shaped contact area 152a of the distance equalization plate portion 152 and presses against the metal disk 146 from below within its outer edge area 146a. In this case, the support ring 158 is part of the seal 112, but this is not necessarily required.

[0078] The support ring 158 provides additional security features, particularly in the event of increased pressure within the housing 102, where the aforementioned tension on the distance equalization structure 154 could cause the entire distance equalization plate portion 152 to rise, possibly along with the contact plate portion 142, without the connection area 154a being torn. In this case, the CID would not function.

[0079] However, this situation is avoided by the support ring 158. If the metal disk 146 bulges outward, the support ring 158 holds the distance equalization plate portion 152 in place, ensuring that it does not tear from the connection area 154a, thereby ensuring the function of the CID.

[0080] In particular, conventional flanging methods are used for closing the circular opening 106 of the housing cup 104 by the cover assembly 108. The housing cup 104 has a free end section 160, which is initially cylindrical or possibly slightly conical before closure, as shown by a dashed line in Figure 1. The sealant 112 also has a free end section, denoted by 162, which preferably extends radially inward adjacent to the end section 160 of the housing cup 104 before closure, as also shown by a dashed line in Figure 1.

[0081] In the flanging method, the free end section 160 of the housing cup 140 is bent radially inward, and the sealant 112 is supported together by the free end section 106, which in this case is wrapped around the closure ring 110 of the cover assembly 108. As a result, the sealant 112 is compressed by the free end section 160 of the housing cup 104, which is bent radially inward in the axial direction relative to the cover assembly 108.

[0082] In this case, in order to maintain an axial force acting in the direction of the cup base 104a away from the winding body 136 or the electrode-separator complex 114, the housing 102 has a tool section 104d in the axial direction between the central section 104b and the closure section 104c, and the tool engagement structure 164 is formed within the housing cup 104.

[0083] The tool engagement structure 164 has the function of having a radial embossing on the inside 102a of the housing so that a tool can be applied to the housing 102 when the opening 106 or the housing cup 104 is closed. The opposing tool engages from the outside within the tool engagement structure 164 when the opening 106 is closed, which supports the housing cup 104 axially against the forces acting during the flanging method and dissipates these forces so that the winding body 136 remains substantially free from the action of the force.

[0084] The tool engagement structure 164 occupies an area inside the housing 102a so that the corresponding tool can be applied to the housing 102, which is no longer available for the winding body 136 due to the thus reduced cross-section. The position of the tool engagement structure 164 in the axial direction determines the distance d between the main areas 120, 130 of the anode 116 or cathode 126 and the closure plane 108a of the closure assembly 108, which is denoted by d in Figure 1.

[0085] The axial extensions of the cover assembly 108, the distance equalization plate portion 152, and the contact plate portion 142 are matched to this distance d. In particular, the domed distance equalization structure 154 of the distance equalization plate portion 152 bridges the intermediate space 170 between the contact plate portion 142 and the inner side portion 150b of the metal disk 146, into which the tool engagement structure 164 protrudes.

[0086] In the energy storage cell 10 shown in Figure 1, the tool engagement structure 164 is formed by a bead 166, which points inward radially and is perfectly circular in the circumferential direction, providing a tool engagement bead 168. However, other structures are also conceivable.

[0087] In the structure of this energy storage cell 10, the tool engagement structure 164 and, in particular, the tool engagement bead 168 are first generated after the winding body 136 has already been positioned inside 102a of the housing 102. Otherwise, the winding body 136 would strike the tool engagement bead 168, and the path to the interior 102a would be blocked due to the relatively small cross-section there. Next, the cover assembly 108 is positioned on the tool engagement bead 168 together with the sealant 112, and the flanging procedure takes place.

[0088] Furthermore, it should be noted that in this case, the illustrated bead has a slight undercut. This can be a result of height calibration, which may occur, for example, during or after flanging. The bead 166 is preferably initially formed for tool engagement without any visible undercut. The undercut is initially formed during calibration.

[0089] 2. Energy storage cell according to the present invention Figures 3 to 7 show the energy storage cell 100 according to the present invention, where functionally corresponding components and parts have the same reference numerals as in the energy storage cell 10 in Figure 1, except now only the longitudinal axis has the reference numeral 100a. Therefore, unless otherwise described, the descriptions made for the energy storage cell 10 for Figures 1 and 2 apply to these parts and components.

[0090] In the energy storage cell 100 according to the present invention, the projection 141a formed by the edge strip 124 of the anode current collector 118 between the main area 120 and the contact plate portion 142 of the anode current collector 118 is compressed axially in relation to the winding body 136. In particular, the edge strip 124 is compressed and / or bent for this purpose. Figure 3 shows this based on a magnified view of its internal details. This projection 141a of the axially compressed anode current collector 118 is separately indicated by 172. Thus, the energy storage cell 100 according to the present invention has an electrode-separator complex 114 having an axially compressed projection 172. In the illustrated configuration of the winding body 136, the compressed protrusion 172 is the protrusion 141a of the anode current collector 118 formed by the edge strip 124, and in the inverted configuration of the winding body 136 described above (not shown separately here), the compressed protrusion 172 is the protrusion 141b of the cathode current collector 128 formed by the edge strip 134. The winding body 136 is shown along with a partial view of the anode main area 120 and the cathode main area 130, although the separators 138 and 140 are not shown for clarity.

[0091] The bending can occur, for example, in the manner described in (Patent Document 2) above, in that the outer free winding of the edge strip 124 of the anode collector is bent radially inward and also compressed, while the winding of the edge strip 124 is further positioned radially inward when the contact plate portion 142 is positioned before welding. For example, the edge strip can be bent by an angle in the range of 30 to 90°. The edge strip can also be notched for this purpose, although this is not absolutely necessary.

[0092] Compression can occur, for example, when the contact plate is pressed onto the edge strip in a way that causes it to deform. In many cases, this does not result in direct bending, but rather indirect compression. Thus, sections of the edge strip can be bent radially outward, while other sections can be bent radially inward.

[0093] Both bending and compression result in support surfaces formed by compact or reinforced protrusions as a consequence of bending and / or compression.

[0094] In general terms, the axially compressed protrusion 172 has relatively greater stability and load-bearing capacity against axially acting forces on the compressed protrusion 172 than the case with the protrusions 141a and 141b in the unloaded winding configuration described above in Figure 2.

[0095] The compressed projection 172 here has a relatively smaller axial extension than the projections 141a and 141b in the winding configuration. The axial extension of the axially compressed projection 172 is, in particular here, 10% to 80%, preferably 15% to 60%, more preferably 15% to 50%, and even more preferably 25% to 45% of the axial extension of the projections 141a and 141b in the loaded winding configuration. The compressed projection 172 can also be compressed to an axial extension of perhaps less than 10% of the axial extension of the projections 141a and 141b in the loaded winding configuration.

[0096] In the energy storage cell 100 according to the present invention as shown herein, the housing cup 104 is formed without a tool engagement structure 164. Therefore, as described above, the tool engagement structure 164 used when closing the opening 106 of the housing cup 104 to apply a tool to the housing cup is absent, whether in the form of a tool engagement bead 166 or in the form of another structure having a corresponding function.

[0097] However, due to the compressed or bent edge strip 172 of the anode collector 118, the electrode-separator complex 114, i.e., the winding body 136, together with the contact plate portion 142 welded to the top, is sufficiently stable to counteract the axial force acting during closure as a counteracting element, so that the end section 160 of the housing cup can be bent without the risk of damage to the winding body 136.

[0098] Here, a different closing method is used than in the case of a housing with a tool engagement structure. For example, radial bending can be performed by rotating rollers, which move circumferentially along the free end section 160 of the housing cup 104 and press radially inward and axially toward the cup base 104a in this case. Here, perhaps, work steps required in the case of an energy storage cell 100 having a housing 102 with a tool engagement structure 164, such as the height calibration described above, can be omitted.

[0099] Since no tool engagement structure is provided, the housing cup 104 can be formed cylindrical from the base 104a to the closure section 104c. Thus, in relation to the housing 102 having a tool engagement structure 164 which is otherwise identical, the intermediate space 170 between the contact plate portion 142 and the inner side portion 150b of the metal disk 146 can be kept relatively short in the axial direction, and consequently the winding body 136 can be formed to be relatively long in the axial direction. The relatively long winding body 136 in the axial direction results in an energy storage cell 100 with relatively large capacity and performance, while the external dimensions of the other parts remain constant.

[0100] In Figure 3, the axial distance between the main areas 120 and 130 of the anode 116 and cathode 126 and the closure plane 108a of the cover assembly is denoted by d1. For comparison, Figure 3 also again shows the corresponding distance d in the energy storage cell 100 having the tool engagement structure 164 according to Figure 1.

[0101] As is clear, the distance d1 is smaller than the distance d by △d, and the winding body 136 used according to the present invention has an axial extension of the main areas 120, 130 of the anode 116 and cathode 126 that is larger by △d than the winding body 136 in Figure 1. The cover assembly 108 and the distance equalization plate portion 152 are fitted to the intermediate space 170, which are now shortened in the axial direction. In particular, the domed distance equalization structure 154 of the distance equalization plate portion 152 is formed in a substantially relatively flat state, as shown by comparison with Figure 1. Also in the embodiment for this example, a metal disk 142 is fitted, which bulges toward the distance equalization plate portion 152 in an area whose boundary is defined radially outward by the groove 146b. This bulge is also now relatively small, as shown by comparison with Figure 1.

[0102] The housing 102 of the energy storage cell 100 preferably has a length or height of 50 mm to 150 mm. Its diameter is preferably in the range of 15 mm to 60 mm. In a particularly preferred embodiment, it has format 21700.

[0103] In the case of a housing 102 with other parts unchanged, the combination of a winding body 136 used according to the present invention having a compressed protrusion 172 and a housing 102 according to the present invention without a tool engagement structure makes it possible to achieve a d1 value of, for example, 0.6 mm to 3.0 mm, particularly 0.8 mm to 2.5 mm, preferably 1.0 mm to 2.0 mm, preferably 1.2 mm to 1.6 mm, and a Δd value of, for example, 1.2 mm to 2.5 mm, particularly 1.8 mm to 2.2 mm, which makes it possible to form the main areas 120, 130 of the anode 116 and cathode 126 in a relatively elongated state in the axial direction. For typical housing dimensions with a winding body diameter of 15 mm to 60 mm, these Δd values ​​result in a capacity increase of 1% to 3%.

[0104] Overall, the values ​​of d1, △d, and the resulting capacity increase clearly depend on the design and basic dimensions of the energy storage element.

[0105] In the exemplary embodiment shown in Figure 3, the support ring 158 is also a part of the sealant 112. The sealant here has a C-shaped cross-section in particular, and the support ring 158 is formed by the legs of the sealant 112 that press against the inner side portion 110a of the closure ring 110 of the cover assembly 108. This configuration is shown in Figure 3.

[0106] Figure 4 shows a deformation in which the distance equalization structure 154 is provided by the contact plate portion 142. In this case, the contact plate portion 142 is structurally formed in a state corresponding to the distance equalization plate portion 152, and the ring-shaped contact area 142a of the contact plate portion 142 is merged radially inward into the distance equalization structure 154.

[0107] In this case, the support ring 158 is seated directly on the contact plate portion 142. Figure 4 shows this variation with an unchanged distance d1, and the distance equalization structure 154 has a corresponding axial extension. The sealant 112 and the support ring 158 are adapted thereto. However, even in this case, the distance d1 can be reduced accordingly, since the distance equalization structure 154 is formed in a relatively flat state in the same manner as the distance equalization plate portion 152 shown in Figures 3, 5, and 6.

[0108] Figure 5 shows an embodiment for a second example of an energy storage cell according to the present invention, in which the sealant 112 and the support ring 158 are formed as separate parts. Here, a predetermined distance exists between the sealant 112 and the contact plate portion 142.

[0109] In a deformation in which the distance equalization structure 154 is provided by the contact plate portion 142, the support ring 158 is seated directly on the contact plate portion 142 in this case.

[0110] Figure 6 shows an embodiment for a third exemplary energy storage cell 100 according to the present invention, in which case the sealant 112 and the support ring 158 are also formed as separate parts. In contrast to the embodiment for the second exemplary, the sealant 112 is supported on the contact plate portion 142 and has a support section 112a for this purpose. The support section 112a for the sealant 112 extends radially adjacent to the distance equalization plate portion 152 and extends axially between the inner side portion 110a of the ring section 110 of the cover assembly 108 and the contact plate portion 142.

[0111] In this case, a separate support ring 158 can be omitted such that the support section 112a of the sealant 112 forms a support ring 158 when the distance equalization structure 154 is provided by the contact plate portion 142. As a result, the support ring 158 is formed, possibly by the support section 112a of the sealant 112, so that it seats further away and radially inward on the contact plate portion 142.

[0112] Figure 7 shows an embodiment for a fourth example of an energy storage cell 100 according to the present invention, in which the encapsulant 112 has both a support section 112a and a support ring 158.

[0113] Due to the removal of the tool engagement structure, it is further possible to pre-weld the winding body 136 and the cover assembly 108 to each other before inserting the winding body 136 into the housing 102, because, as described above with reference to Figure 1, there is no structure preventing the passage of the winding body 136 into the housing 102.

[0114] This opens up a pathway for the manufacturing method described in the introductory section, in which a cover winding composite, shown only in its entirety by 174 in Figure 3, is first manufactured and then subsequently introduced into the housing cup 104.

Claims

1. An energy storage element, a) A housing (102) having a metal housing cup (104) and a cover assembly that closes the housing cup (104), defining the longitudinal axis (100a) and interior (102a) of the energy storage element (100), b) A sealing configuration comprising a sealant (112) that encloses the cover assembly (108) radially and seals it against the housing cup (104), wherein the sealant (112) is compressed against the cover assembly (108) by the free end section (160) of the housing cup (104) which is bent radially inward, c) An electrode-separator complex (114) housed within the housing cup (104) and provided in the form of a cylindrical wound body (136), having the sequence anode (116) / separator (138) / cathode (126) / separator (140), c1) The anode (116) is an anode current collector (118) having a band-shaped main area (120) covered by a layer made of a negative electrode material (122), and a free edge strip (124) that is not covered by the electrode material (122) and has a first longitudinal edge (118a) of the anode current collector (118), wherein the free edge strip (124) emerges from the first terminal end face (114a) of the electrode-separator composite (114) and forms a projection (141a) at the first end face (114a), c2) The cathode (126) is a cathode current collector (128) having a band-shaped main area (130) covered by a layer made of positive electrode material (132), and a free edge strip (134) that is not covered by the electrode material (132) and has a first longitudinal edge (128a) of the cathode current collector (128), wherein the free edge strip (134) emerges from the second terminal end face (114b) of the electrode-separator composite (114) and from a projection (141b) on the second end face (114b), Electrode-separator composite (114), d) Contact plate portion (142), d1) A component seated on the protruding portion (141a) of the anode current collector (118), covering the first terminal end surface (114a) of the electrode-separator composite (114), and connected thereto, Or, d2) A contact plate portion (142) is seated on the protruding portion (141b) of the cathode current collector (128), covers the second terminal end surface (114b) of the electrode-separator composite (114), and is connected thereto. In an energy storage element having, e) The protrusions (141a, 141b) connected to the contact plate portion (142) are protrusions (172) that are compressed in the axial direction, f) The housing cup (104) is formed without a tool engagement structure (164). An energy storage element characterized by the following features.

2. The energy storage element according to claim 1, characterized in that the cover assembly (108) defines a closure plane (108a), and the axial distance (d1) between the main areas (120, 130) of the anode (116) and cathode (118) and the closure plane (108a) is 0.6 mm to 3.0 mm, particularly 0.8 mm to 2.5 mm, preferably 1.0 mm to 2.0 mm, and preferably 1.2 mm to 1.6 mm.

3. The energy storage element according to claim 2, characterized in that the cover assembly (108) has a circumferential outer closure ring (110) which is sealed by the sealant (112), and the closure plane (108a) is bounded by the inner side portion (110a) of the closure ring (110) facing toward the interior (102a) of the housing (102).

4. The cover assembly (108) has a metal disc (146), the metal disc (146) is welded to the distance equalization structure (154) within the connection area (154a) of the distance equalization structure (154), and the distance equalization structure (154) is a) Provided by the distance equalization plate portion (152) connected to the contact plate portion (142), b) Provided by the contact plate portion (142) The energy storage element according to claim 3, characterized in that

5. The distance equalization structure (154) is provided by the distance equalization plate portion (152), a) A support ring (158) is provided between the distance equalization plate portion (142) and the metal disk (146), and the support ring (158) is either a separate portion or is composed of the sealant (112), b) A predetermined distance exists between the contact plate portion (142) and the sealant (112) in the axial direction, or the sealant (112) has a support section (112a) and the sealant (112) is supported on the contact plate portion (142) using the support section (112a). The energy storage element according to claim 4, characterized in that

6. The energy storage element according to claim 4, characterized in that the distance equalization structure (154) is provided by the contact plate portion (142), a support ring (158) is provided between the contact plate portion (142) and the metal disk (146), and the support ring (158) is a separate portion or is composed of the sealant (112).

7. The energy storage element according to claim 5 or 6, wherein the distance equalization structure (154) provides a CID function, and for this purpose is characterized in that it has a material weakening, in particular a groove (156), located on the side of the connection area (154a) of the distance equalization structure (154).

8. The energy storage element according to any one of claims 5 to 7, wherein the metal disk (146) is designed as a PRV and, for this purpose in particular, has a material weakening groove (156) in the form of a ring or a circular ring.

9. A method for manufacturing an energy storage element (100) according to any one of claims 1 to 8, (A) Providing the housing (102) having the metal housing cup (104) and the cover assembly (108), (B) Providing the sealing configuration having the sealing body (112) and providing the support ring (158), (C) The step of providing the electrode-separator composite (114), (D) Connecting the contact plate portion (142) to the edge strip (124) of the anode collector (118) or to the edge strip (134) of the cathode collector (128), particularly by welding, (E) A step of positioning the sealing body (112) and the support ring (158), (F) The step of connecting the cover assembly to the contact plate portion (142), (G) The step of closing the housing cup (104), In a method having, (H) Preferably, before or during the execution of step (D), the step of compressing or bending the edge strips (124, 130) in the axial direction, (I) Steps (D), (E), and (F), and (H) are performed on the outside of the housing cup (104) so ​​that a cover winding composite (174) is formed, (K) Before performing step (G), the step of introducing the cover winding composite (174) and the seal (112) into the housing cup (104), A method characterized by the following.

10. (L) The distance equalization structure (154) is provided by the distance equalization plate portion (152), and in step (F), the cover assembly (108) is connected to the distance equalization structure (154), and the distance equalization plate portion (152) is connected to the contact plate portion, or (M) The distance equalization structure (154) is provided by the contact plate portion (142), and in step (F), the cover assembly (108) is connected to the distance equalization structure (154). The method according to claim 9, characterized in that

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