Energy storage cell

Abstract

An energy storage cell (100) is known that includes a composite (104) in the form of a cylindrical winding composed of strip-shaped electrodes and separators, the composite (104) having two terminal end faces (104b, 104c) and a winding casing (104a). Each electrode has a corresponding current collector (115, 125), and the electrodes are designed and / or arranged relative to each other within the composite so that the longitudinal edge of the negative electrode protrudes from one of the end faces (104b, 104c) and the longitudinal edge of the positive electrode protrudes from the other end face. The composite (104) is axially oriented within a housing that includes a tubular metal housing part (101) with a terminal circular opening (101c) such that the winding casing (104a) rests against the inner surface (101b) of the tubular housing part (101). For electrical contact with one of the electrodes, the cell (100) comprises a contact element (110) which is in direct contact with one of the longitudinal edges (115a, 125a) protruding from one end face and which is connected to the longitudinal edge by welding. According to the invention, the terminal circular opening (101c) of the tubular housing part (101) is to be closed in an airtight and liquid-tight manner by the contact element (110). For this purpose, the contact element (110) has a circular edge (110a) and is or includes a metal membrane (111; 151) which bends when the pressure inside the housing exceeds a threshold value, thereby removing the electrical contact between the contact element and the first longitudinal edge.

Description

[Technical Field]

[0001] The present invention, described below, relates to an energy storage cell comprising an electrode-separator assembly. [Background technology]

[0002] An electrochemical cell can convert stored chemical energy into electrical energy through oxidation-reduction reactions. An electrochemical cell generally comprises positive and negative electrodes separated from each other by a separator. During discharge, electrons are released at the negative electrode as a result of the oxidation process. This results in an electron current, which can be drawn in by an external consumer. The electrochemical cell functions as an energy source for the consumer. Simultaneously, an ionic current corresponding to the electrode reaction is generated within the cell. This ionic current passes through the separator and is enabled by an ionic conductive electrolyte.

[0003] A cell is called a secondary battery if its discharge is reversible, meaning that the conversion of chemical energy to electrical energy that occurs during discharge can be reversed, and therefore the cell can be recharged. It is customary in secondary batteries to designate the negative electrode as the anode and the positive electrode as the cathode, which relates to the discharge function of the electrochemical cell.

[0004] Secondary lithium-ion batteries are used in many applications today because they can supply high currents and have a relatively high energy density. Secondary lithium-ion batteries are based on the use of lithium, which can move back and forth between the electrodes of the cell in the form of ions. The negative and positive electrodes of a lithium-ion battery are usually formed from electrodes known as so-called composite electrodes, which contain electrochemically inert components in addition to electrochemically active components.

[0005] Useful electrochemically active components (active materials) for secondary lithium-ion batteries are, in principle, any material capable of absorbing and releasing lithium ions. In many cases, carbon-based particles, such as graphite carbon, are used for the negative electrode. Other non-graphite carbon materials suitable for lithium intercalation can also be used. In addition, metallic and semimetallic materials capable of alloying with lithium can also be used. For example, the elements tin, aluminum, antimony, and silicon can form intermetallic phases with lithium. Examples of active materials that can be used for the positive electrode are:

[0006] This includes lithium cobalt (LiCoO2), lithium manganese oxide (LiMn2O4), lithium iron phosphate (LiFePO4), or derivatives thereof. Electrochemically active materials typically exist in particulate form within electrodes.

[0007] As an electrochemically inert component, the composite electrode generally comprises a two-dimensional and / or ribbon-shaped current collector, such as a metal foil that functions as a carrier for the active material. The current collector for the negative electrode (anode current collector) can be formed from, for example, copper or nickel, and the current collector for the positive electrode (cathode current collector) can be formed from, for example, aluminum. In addition, the electrode may also contain, as an electrochemically inert component, an electrode binder (e.g., polyvinylidene fluoride (PVDF), or another polymer, such as carboxymethylcellulose), conductivity improving additives, and other additives. The electrode binder ensures the mechanical stability of the electrode and, more often, the adhesion of the active material to the current collector.

[0008] Lithium-ion batteries generally contain lithium salt solution, such as lithium hexafluorophosphate (LiPF6) in an organic solvent (e.g., carbonate ether and ester), as the electrolyte.

[0009] In the manufacture of lithium-ion batteries, composite electrodes are combined with one or more separators to form the composite body. In this case, the electrodes and separators are typically joined to each other under pressure, and optionally by lamination or adhesive bonding. The basic ability of the cell to function can be established by impregnating the assembly with electrolyte.

[0010] In many embodiments, the composite body is formed as a winding or processed to result in a winding. Generally, the composite body includes an electrode / separator / negative electrode sequence. Often, the composite body is fabricated as a so-called bicell, and its expected sequence is negative electrode / separator / positive electrode / separator / negative electrode, or positive electrode / separator / negative electrode / separator / positive electrode.

[0011] The automotive sector, electric bicycles, or other applications requiring high energy, such as tools, require lithium-ion batteries with maximum energy density that can simultaneously inject high currents during charging and discharging.

[0012] In many cases, cells for the aforementioned applications take the form of a circular cylindrical cell, for example, having a shape factor of 21 × 70 (diameter × height, in millimeters). This type of cell always includes a composite body in the form of a winding. Modern lithium-ion batteries of this shape factor have already achieved energy densities of up to 270 Wh / kg. However, this energy density is considered to be only an intermediate step. The market is already demanding cells with even higher energy densities.

[0013] However, in the development of improved electrochemical cells, energy density is not the only factor to consider. The internal resistance of the cell, which must be kept to a minimum to reduce power loss during charging and discharging, and the thermal connection of the electrodes, which can be important for temperature regulation of the cell, are also critical parameters. These parameters are also very important for circular cylindrical cells that include a composite body in the form of a winding. During rapid charging of the cell, power loss can lead to heat accumulation in the cell, which can lead to large thermomechanical stresses and subsequent deformation and damage to the cell structure. The risk is amplified when the electrical attachment of the current collector is done via separate electrical output conductor lugs that project axially from the wound composite body, because localized heating can occur in these output conductor lugs under high load during charging or discharging.

[0014] International Publication No. 2017 / 215900A1 describes an electrode-separator assembly and a cell in which the electrodes are ribbon-shaped and winding-shaped. Each electrode has a current collector on which the electrode material is provided. Electrodes of opposite polarity are arranged offset from each other within the electrode-separator assembly, so that the longitudinal edge of the positive electrode current collector protrudes from the winding on one side, and the longitudinal edge of the negative electrode current collector protrudes from the winding on the other side. For electrical contact connection of the current collectors, the cell has at least one contact element resting in contact with one of the longitudinal edges so as to provide a linear contact zone. The contact element is joined to the longitudinal edge along the linear contact zone by welding. This allows for electrical contact along the entire length of the current collector and therefore with the corresponding electrode. This significantly reduces the internal resistance within the described cell. As a result, the generation of high currents can be controlled very well.

[0015] Nevertheless, electrochemical cells can fail due to aging, mechanical damage, incorrect charging, and several other reasons. These failures can result in unnecessary heating or gas generation within the cell, potentially causing the pressure inside the cell to rise uncontrollably. In such cases, electrochemical cells generally have safety measures. In this regard, the use of a so-called CID (current interruption device), which disconnects the electrical contact between the terminals and the electrodes connected to them, should be particularly emphasized if the gas pressure inside the cell becomes excessive.

[0016] However, CIDs are relatively complex structures and are usually installed as additional assemblies. CIDs occupy a relatively large space within the cell housing, which is counterproductive to the goal of improving energy density. [Overview of the Initiative] [Means for solving the problem]

[0017] The object of the present invention is to provide an energy storage cell characterized by improved energy density and a uniform current distribution over the maximum area and length of its electrodes, while simultaneously having superior characteristics with respect to its internal resistance and active cooling properties compared to the prior art. However, the cell must also be characterized in particular by improved safety and manufacturability. This objective is achieved by an energy storage cell having the features of claim 1. Preferred configurations of the cell will become apparent from the dependent claims.

[0018] The energy storage cell of the present invention always has at least the following features a. to j.: a. The cell comprises an electrode-separator assembly having an anode / separator / cathode sequence. b. The electrode-separator assembly takes the form of a cylindrical winding with two terminal end faces and a wound jacket. c. The cell comprises a housing that includes a metal tubular housing component having a terminal circular opening. d. The electrode-separator assembly in the form of a wound coil is axially aligned within the housing such that the wound jacket is adjacent to the inside of the tubular housing part. e. The anode is in the form of a ribbon and comprises a ribbon-shaped anode current collector having a first longitudinal edge and a second longitudinal edge. f. The anode current collector comprises a strip-shaped main region provided with a layer of negative electrode material and a free edge strip extending along the first longitudinal edge and provided with no electrode material. g. The cathode is in the form of a ribbon and comprises a ribbon-shaped cathode current collector having a first longitudinal edge and a second longitudinal edge. h. The cathode current collector comprises a strip-shaped main region provided with a layer of positive electrode material and a free edge strip extending along the first longitudinal edge and provided with no electrode material. i. The anode and the cathode are formed and / or arranged within the electrode-separator assembly such that the first longitudinal edge of the anode current collector extends beyond one of the terminal end faces and the first longitudinal edge of the cathode current collector extends beyond the other of the terminal end faces. j. The cell comprises at least a partially metallic contact element that directly contacts and is welded to one of the first longitudinal edges.

[0019] Preferred embodiments of the electrochemical system In principle, the invention includes an energy storage cell, regardless of its electrochemical configuration. However, in a particularly preferred embodiment, the energy storage cell of the invention is a lithium-ion battery, particularly a secondary lithium-ion battery. Thus, in principle, all electrode materials known for secondary lithium-ion batteries can be used for the anode and the cathode of the energy storage cell.

[0020] The active material used in the negative electrode of the energy storage cell of the present invention in the form of a lithium ion battery is a carbon-based particle capable of intercalating lithium, preferably also in particle form, such as a graphite carbon material or a non-graphite carbon material. Alternatively or in addition, lithium titanate (Li4Ti5O 12 ) or a derivative thereof can preferably also be contained in the negative electrode in particle form. In addition, the negative electrode as the active material can optionally contain at least one material from the group of silicon, aluminum, tin, antimony, or compounds or alloys of these materials, such as silicon oxide, which can reversibly intercalate and deintercalate lithium, in combination with a carbon-based active material. Tin, aluminum, antimony, and silicon can form an intermetallic phase with lithium. Here, especially in the case of silicon, the ability to absorb lithium exceeds the value of graphite or equivalent materials and is several times that value. It is also possible to use a thin anode of metallic lithium.

[0021] Examples of useful active materials for the positive electrode of the energy storage cell of the present invention in the form of a lithium ion battery include lithium metal oxide compounds and lithium metal phosphate compounds, such as LiCoO2 and LiFePO4. Also highly suitable are lithium nickel manganese cobalt oxide (NMC) having the molecular formula LiNi x Mn y Co z O2 (x + y + z is typically 1), lithium manganese spinel (LMO) having the molecular formula LiMn2O4, or lithium nickel cobalt aluminum oxide (NCA) having the molecular formula LiNi x Co y Al z O2 (x + y + z is typically 1). Their derivatives, for example, the empirical formula Li 1.11 (Ni 0.40 Mn 0.39 Co 0.16 Al 0.05 ) 0.89 O2, or Li 1+xLithium nickel manganese cobalt aluminum oxide (NMCA) having MO compounds, and / or mixtures of these materials, may also be used. The cathode active material is also preferably used in particulate form.

[0022] In addition, the electrodes of the energy storage cell of the present invention in the form of a lithium-ion battery preferably include an electrode binder and / or additives for improving electrical conductivity. The active material is preferably embedded in the matrix of the electrode binder, and adjacent particles in the matrix are preferably in direct contact with each other. The conductive agent plays a role in increasing the electrical conductivity of the electrode. Typical electrode binders mainly consist of polyvinylidene fluoride (PVDF), polyacrylate, or carboxymethylcellulose, for example. Typical conductive agents are carbon black and metal powders.

[0023] The energy storage cell of the present invention preferably comprises, in the case of a lithium-ion battery, an electrolyte based on at least one lithium salt, for example, lithium hexafluorophosphate (LiPF6) dissolved in an organic solvent (for example, in a mixture of organic carbonates or cyclic ethers, such as THF or nitriles). Other usable lithium salts include, for example, lithium tetrafluoroborate (LiBF4), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), and lithium bis(oxalate)borate (LiBOB).

[0024] Preferred Embodiment of Separator The electrode-separator assembly preferably comprises at least one ribbon-shaped separator, more preferably two ribbon-shaped separators, wherein the separators, or each of them, have first and second longitudinal edges.

[0025] The separator is preferably formed from an electrically insulating polymer film. It is preferable that the separator is permeable to the electrolyte. For this purpose, for example, the polymer film used may have micropores. The film may also be composed of, for example, polyolefin or polyetherketone. Nonwoven and woven fabrics made from polymer materials, or other electrically insulating sheet-like structures, can also be used as the separator. It is preferable to use a separator with a thickness in the range of 5 μm to 50 μm. In some embodiments, the separator of the composite may also be one or more layers of solid electrolyte.

[0026] Preferred structure of a wound electrode-separator assembly In a wound electrode-separator assembly, the ribbon-shaped anode, ribbon-shaped cathode, and ribbon-shaped separator preferably take the form of a spiral winding. To produce the electrode-separator assembly, the ribbon-shaped electrode is supplied to a winding device together with the ribbon-shaped separator and preferably wound spirally around a winding axis therein. In some embodiments, the electrode and separator are wound for this purpose onto a cylindrical or hollow cylindrical winding core that is placed on a winding mandrel and remains in the winding after the winding operation. The wound jacket may be formed, for example, from a polymer film or adhesive tape. The wound jacket may also be formed from one or more separate windings.

[0027] It is preferable that the longitudinal edge of the separator forms the end face of the winding-shaped electrode-separator assembly. It is even more preferable that the longitudinal edge of the anode current collector and / or cathode current collector protruding from the terminal end face of the winding protrudes by 5000 μm or less, preferably 3500 μm or less, from its end face, and particularly from the end face formed by the longitudinal edge of the separator.

[0028] More preferably, the longitudinal edge of the anode current collector protrudes from the end face of the winding by 2500 μm or less, more preferably 1500 μm or less. More preferably, the longitudinal edge of the cathode current collector protrudes from the end face of the winding by 3500 μm or less, more preferably 2500 μm or less.

[0029] Preferably, the ribbon-shaped anode and ribbon-shaped cathode are offset from each other within the electrode-separator assembly to ensure that the first longitudinal edge of the anode current collector extends beyond one of the terminal end faces and the first longitudinal edge of the cathode current collector extends beyond the other of the terminal end faces.

[0030] Preferred Embodiment of a Current Collector The current collector of an energy storage cell is responsible for making electrical contact with the electrochemically active components present in the corresponding electrode material over the maximum possible area. The current collector is preferably made of a metal, or at least its surface is metallized. In the energy storage cell of the present invention in the form of a lithium-ion battery, suitable metals for the anode current collector are, for example, copper or nickel, or other conductive materials, particularly copper alloys and nickel alloys, or nickel-plated metals. Stainless steel is also useful in principle. In the case of the energy storage cell of the present invention in the form of a lithium-ion battery, suitable metals for the cathode current collector are, in particular, aluminum, or other conductive materials including aluminum alloys.

[0031] The anode current collector and / or cathode current collector are preferably metal foils having a thickness in the range of 4 μm to 30 μm, and more particularly, ribbon-shaped metal foils having a thickness in the range of 4 μm to 30 μm. However, in addition to foil, the current collector used may also be a ribbon-shaped substrate, such as a metal or metallized nonwoven fabric, an open-porous metal foam, or expanded metal.

[0032] The current collector is preferably provided with corresponding electrode material on both sides. In some particularly preferred configurations, the cell of the present invention may be characterized by having at least one of the following features a. to c.: a. The main strip-shaped region of the current collector, which is joined to the contact element by welding, has numerous openings. b. Openings in the main area are circular or square holes, in particular punch holes or drilled holes. c. Current collectors, which are joined to contact elements by welding, have their main regions perforated, particularly by drilling round or grooved holes. Preferably, the preceding features a. and b., or a. and c., more preferably, the three preceding features a. to c. are realized in combination with each other.

[0033] As a result of the numerous openings, the volume of the current collector decreases, and its weight also decreases. This makes it possible to introduce more active material into the cell, and thus significantly increase the energy density of the cell. In this way, an increase in energy density of two-digit percentages can be achieved. In some preferred embodiments, the aperture is introduced into the main region in a strip by a laser.

[0034] The geometric shape of the opening is, in principle, not an essential feature of the present invention. What is important is that, as a result of introducing the opening, the mass of the current collector is reduced, and the opening can be filled with the active material, thus creating more space within the opening for the active material.

[0035] When introducing an opening, it can be very advantageous to ensure that the maximum diameter of the opening is not too large. Preferably, the dimensions of the opening should not exceed twice the thickness of the layer of electrode material on the corresponding current collector.

[0036] In a particularly preferred configuration, the cell of the present invention is characterized by having the following feature a.: a. The opening in the current collector, particularly in the main region, has a diameter in the range of 1 μm to 3000 μm. Within this preferred range, diameters in the range of 10 μm to 2000 μm, preferably 10 μm to 1000 μm, and more preferably 50 μm to 250 μm are preferred.

[0037] The cell of the present invention is particularly preferred if it is characterized by having at least one of the following additional features a. and b.: a. A current collector joined to a contact element by welding has a weight per unit area that is smaller in at least the subsection of the main region than in the free edge strip of the same current collector. b. Current collectors joined to contact elements by welding have fewer openings per unit area compared to the main region, if there are openings in the free-edge strip. It is particularly preferable that the preceding features a. and b. are realized in combination with each other.

[0038] The free-edge strips of the anode and cathode current collectors define the boundary of the main region on the side of the first longitudinal edge. Preferably, both the anode and cathode current collectors each include free-edge strips along both of their longitudinal edges. The opening characterizes the main region. In other words, the boundary between the main region and the free edge strip corresponds to the transition between the region with the opening and the region without the opening. The openings are preferably distributed essentially uniformly across the main region.

[0039] In a further particularly preferred embodiment, the cell of the present invention is characterized by having at least one of the following features a. to c.: a. The weight per unit area of ​​the current collector in the main region is reduced by 5% to 80% compared to the weight per unit area of ​​the current collector in the free-edge strip. b. In the main region, the current collector has a perforated area ranging from 5% to 80%. c. In the main region, the current collector has a load capacity of 20 N / mm². 2 ~250N / mm 2 It has a tensile strength of [value].

[0040] It is particularly preferable that the preceding features a. to c. are realized in combination with each other.

[0041] The perforated area, also commonly referred to as the free section, can be determined according to ISO 7806-1983. The tensile strength of the current collector in the main area is reduced compared to a current collector without an opening. This can be determined according to DIN EN ISO 527 Part 3.

[0042] The anode and cathode current collectors are preferably identical or similar in design with respect to the aperture. The energy density improvements achievable in each case are additive. Therefore, in a preferred embodiment, the cell of the present invention further has at least one of the following features a. to c.: a. Both the strip-shaped main region of the anode current collector and the main region of the cathode current collector are characterized by a number of openings. b. The cell comprises a first contact element, which is welded to one of the first longitudinal edges, and a second metal contact element, which is welded to the other of the first longitudinal edges. It is particularly preferable that the preceding features a. and b. are realized in combination with each other. The preferred configuration of the current collector with an opening described above can be applied independently to the anode current collector and the cathode current collector.

[0043] Solution of the present invention The specific characteristics of the cell are the following two characteristics k. and l.: k. The contact element has a circular edge and closes the terminal circular opening of the tubular housing component in an airtight and liquid-tight manner. l. The contact element is a metal membrane, or includes one, which is electrically connected to one of the first longitudinal edges and bends when the pressure inside the housing exceeds a threshold, resulting in a loss of electrical contact of the contact element with respect to the first longitudinal edge.

[0044] Therefore, firstly, the contact element of the electrochemical storage element of the present invention is used to contact one of the electrodes and simultaneously functions as a housing component. Secondly, the contact element has CID functionality thanks to the membrane, which, as the central element of the CID, is connected to the electrode assembly very closely and with very low electrical resistance. Thanks to the structure of the present invention, it is possible to operate with fewer components compared to conventional CID structures, as several components simultaneously perform multiple functions. Therefore, particularly advantageously, more space is available for the active material. Furthermore, the assembly of the cell is simplified.

[0045] Loss of electrical contact with one of the first longitudinal edges typically occurs when the first longitudinal edge connected to the contact element breaks and separates from the contact element as a result of the membrane curvature. This preferably breaks the welded joint between the contact element and the first longitudinal edge. However, it is also conceivable that the first longitudinal edge has an intended fracture line along which a crack will occur. Such an intended fracture line may extend, for example, along the boundary between the main region where the opening is provided and one of the free edge strips. If mechanical stress occurs perpendicular to the main extension direction as a result of the membrane curvature, the current collector will preferentially crack along this boundary line.

[0046] Formation of a membrane as a spring element To realize the solution of the present invention, the metal membrane can be formed as a spring element that changes from a first stable state to a second stable or metastable state when a threshold is exceeded, particularly in simple and concise cases. A spring element having a stable first state and a stable second state is one embodiment of a bistable system. A spring element having a stable first state and a metastable second state is also known as a "clicker."

[0047] The ability to utilize the first and second stable states can preferably be achieved by the appropriate shape of the spring element. The second state is stable if the spring element maintains the second state even when the pressure in the housing returns to a value below the pressure threshold. In contrast, "meta-stable" means that as soon as the pressure falls below the pressure threshold, the second state is automatically abandoned and the first state takes precedence.

[0048] When using a contact element that has a membrane in the shape of a spring element or designed to do so, exceeding a threshold may cause an abrupt transition to a second stable or metastable state, resulting in one of the first longitudinal edges tearing away from the contact element.

[0049] When the contact element comprises a membrane in the form of a spring element, it is preferable that the welded joint between one of the first longitudinal edges and the contact element exists exclusively between the first longitudinal edge and the membrane. When the contact element takes the form of a spring element, it is preferable that the welded joint between one of the first longitudinal edges and the contact element exists exclusively in the central region of the contact element affected by bending. The following describes some particularly preferred embodiments of the contact element and their use in particularly preferred modifications of the present invention.

[0050] Preferred embodiment of electrical mounting of contact elements to electrode-separator assemblies in the form of contact elements / windings

[0051] In a first preferred variant of the present invention, the energy storage cell has at least one of the following four features a. to d.: a. The contact element comprises a metal disc as a membrane, and furthermore, a terminal cover, each having a circular circumference. b. The metal disc is in direct contact with one of the first longitudinal edges and is joined to the longitudinal edge by welding. c. The metal disk and terminal cover surround the internal space, and when the threshold is exceeded, the metal disk bends into the internal space. d. At least one spacer element is positioned within the internal space, which prevents bending into the internal space when below a threshold and collapses and / or compresses when above the threshold. The implementation of the combination of the preceding features a. and b. is preferable. The implementation of the combination of the preceding features a. to d. is particularly preferable.

[0052] The contact element may consist of a plurality of individual parts, including a metal disc, which does not necessarily have to be made entirely of metal. In a particularly preferred embodiment, the contact element may include, for example, a metal terminal cover having a circular circumference, which may be welded onto the metal disc and have approximately or exactly the same diameter as the metal disc, such that the edges of the metal disc and the edges of the terminal cover collectively form the edge of the contact element. In a further embodiment, the edge of the terminal cover may be surrounded by the edge of the metal disc, which is bent radially inward. In a preferred embodiment, there may even be a clamp connection between the two individual parts.

[0053] The internal space of the cell in this invention is preferably not sealed from the cell environment. Generally, the terminal cover has at least one opening through which the pressure can be balanced with the cell environment. As a result, when the membrane bends and enters the internal space, no back pressure buildup occurs within the internal space.

[0054] In order to prevent the metal disk from bending even at pressures below a threshold, a spacer element is provided in a first preferred deformation mode of the present invention. The spacer element preferably abuts the metal disk at one end and the terminal cover at the other end to prevent the membrane from bending and entering the interior too quickly. According to the present invention, the spacer element matches a corresponding desired threshold. For example, the spacer element used may be a plastic or metal part that breaks or deforms plastically at a given pressure.

[0055] In one evolved form of a first preferred variant of the present invention, the cell has at least one of the following three features a. to c.: a. The metal disk has at least one channel and / or dot-shaped recess on one of its sides, the recess protruding as at least one linear and / or dot-shaped ridge on the other side. b. The side having at least one protrusion is in direct contact with one of the first longitudinal edges. c. At least one protrusion and the first longitudinal edge are joined via at least one welding point and / or at least one welding seam. The realization of a combination of the preceding features a. to c. is particularly preferable.

[0056] When a metal disc is bent, the connection between the metal disc and its longitudinal edge must be separated with the greatest possible integrity and reliability. Surprisingly, reliable separation is possible, in particular, when channel-shaped and / or dot-shaped depressions exist and the longitudinal edge is welded to at least one protrusion. More preferably, multiple beads are formed as elongated depressions.

[0057] To ensure that the metal disc can be curved, it must not be too thick. Generally, for example, for a cell with a shape factor of 21 × 70, a metal disc with a thickness in the range of 0.2 to 0.4 mm will meet the requirements. For larger cells, a metal disc with a larger wall thickness should be used where appropriate. For smaller cells, the wall thickness should be thinner where appropriate.

[0058] In a preferred development of the metal disk of the cell of the present invention, the cell is characterized by having at least one of the following two features a. and b.: a. The metal disc has a plurality of channel-shaped depressions on one side surface, preferably in a star-shaped configuration, and the depressions protrude as linear ridges on the other side surface. b. The metal disc has at least one weld seam, preferably two parallel weld seams, in each of the channel-shaped recesses as a result of welding the metal disc to the first longitudinal edge. The realization of the combination of the preceding features a. and b. is particularly preferable.

[0059] The star-shaped configuration and double welded seam ensure a good, and especially uniform, bond of the metal disc to one of the first longitudinal edges. Regarding the bending of the membrane, the pressure threshold and the rate of contact release can be adjusted through the welding configuration, particularly the number, size, and position of the weld seams.

[0060] In a particularly preferred evolution of the first preferred modification of the present invention, the cell has at least one of the following six features a. to f.: a. The contact element includes not only a metal disc but also a contact sheet. b. The contact sheet is in direct contact with one of the first longitudinal edges and is joined to the longitudinal edge by welding. c. The contact sheet is star-shaped and comprises a center and at least three strip-like extensions that also form the star shape. d. The metal disc has a star-shaped recess on one side, in addition to a channel-shaped recess, and the contact sheet is located within the star-shaped recess. e. At least one insulating means positioned between the metal disk and the contact sheet insulates the strip-shaped extension from the metal disk. f. The central parts of the metal disc and the contact sheet are joined to each other by welding. It is preferable to implement the preceding features a. and b. together with features e. and f. It is particularly preferable to implement all combinations of the preceding features a. to f.

[0061] This embodiment ensures virtually optimal electrode mounting without sacrificing low energy density, thanks to the additional contact sheet. This is because, in the solution of the present invention, the star-shaped recesses in the metal disk can accommodate the contact sheet, allowing for a space-saving arrangement of the metal disk and the contact sheet.

[0062] In some embodiments, the contact sheet may have at least one channel-shaped and / or dot-shaped recess, like a metal disc. However, the contact sheet is preferably flat and does not have any channel-shaped and / or dot-shaped recesses.

[0063] The welding of the metal disc to the center of the contact sheet is preferably achieved by only one welding point. This facilitates contact release if the membrane bends.

[0064] In embodiments in which features a. and b. described above are realized together with features e. and f., the contact sheet does not necessarily have to be star-shaped. For example, the contact sheet may also be circular, i.e., disc-shaped, or polygonal.

[0065] In a second preferred variant of the present invention, the energy storage cell has at least one of the following five features a. to e.: a. The contact element comprises a metal disc as a membrane, and furthermore, a terminal cover, each having a circular circumference. b. The contact element comprises a contact sheet that is in direct contact with one of the first longitudinal edges and is joined to the longitudinal edge by welding. c. The metal disk and terminal cover surround the internal space, and when the threshold is exceeded, the metal disk bends into the internal space. d. At least one spacer element is positioned within the internal space, which prevents bending into the internal space when below a threshold and collapses and / or compresses when above the threshold. e. The metal disc and contact sheet are directly joined to each other by welding. The realization of a combination of the preceding features a. to e. is particularly preferable.

[0066] In contrast to the first preferred modification of the present invention, there is no direct connection between the metal disk and the first longitudinal edge. The connection exists only between the contact sheet and the first longitudinal edge.

[0067] Other components of the contact element and spacer element may, in a preferred embodiment, be developed as described in relation to the first preferred modification of the present invention.

[0068] In a third preferred variant of the present invention, the energy storage cell has at least one of the following five features a. to e.: a. The contact element comprises a metal disc having a circular circumference and a contact sheet. b. The contact sheet is in direct contact with one of the first longitudinal edges and is joined to the longitudinal edge by welding. c. The metal disc and contact sheet are separated from each other by at least one electrically insulated spacer. d. The metal disc comprises a metal membrane, or is formed as a membrane in several areas. e. The membrane is preferably in direct electrical contact with the contact sheet until a threshold is exceeded. The realization of a combination of the preceding features a. to e. is particularly preferable.

[0069] The metal disc of the contact element does not necessarily have to be a separate component. For example, the base of the housing cup may also function as the metal disc of the contact element. In a third variant of the present invention, the CID membrane can be incorporated into, for example, the base of the housing cup. When the cell pressure exceeds a threshold, the membrane bends outward, and the electrical connection to the electrode assembly is disconnected. A spacer made of an electrically insulating material prevents electrical contact between the metal disc and the contact sheet. The spacer may be, for example, a plastic ring.

[0070] The membrane may be welded to the contact sheet, in particular, through one or more welding points. However, this is not necessarily the case, for example, when the membrane and the contact sheet are in contact via spring force.

[0071] In one advanced form of a third preferred variant of the present invention, the cell has the following feature a.: a. When the threshold is exceeded, the membrane takes the form of a spring element that changes from a first stable state to a second stable or metastable state. The meaning of the spring element according to the present invention has already been defined above.

[0072] In principle, the contact element may also be provided with a terminal cover, as in the first preferred variant of the present invention. Correspondingly, in a possible development of the third preferred variant of the present invention, the cell has at least one of the following features a. and b.: a. The contact element includes a metal disc and a terminal cover having a circular circumference. b. The metal disc and terminal cover surround the internal space, and when the threshold is exceeded, the membrane bends into the internal space. Here, the metal disk and terminal cover are designed as described in connection with the first preferred modification of the present invention, in a preferred embodiment.

[0073] Modifications related to closure In principle, to seal, it is possible to insert a contact element into the terminal circular opening of a tubular housing component with or without a seal. Accordingly, in a first preferred modification of closure, the following is preferred: a. The cell comprises an annular seal made of an electrically insulating material surrounding the circular edge of the contact element, and, b. The contact elements are arranged within the tubular housing component, along with a seal that seals the terminal circular opening of the tubular housing component, such that the annular seal is adjacent to the inside of the tubular housing component along the circumferential contact zone and contact elements. In the second modification relating to closure, the following is preferred: a. The contact elements are positioned within the tubular housing component such that their edges extend along the circumferential contact zone inside the tubular housing component, and b. The edges of the contact elements are joined to the tubular housing component via circumferential weld seams.

[0074] In order for the edges of the annular seal or contact element to extend inward along the circumferential contact zone, it is preferable that the tubular housing component has a circular cross-section, at least in the section adjacent to the seal. Preferably, this section is in the shape of a hollow cylinder for this purpose. Accordingly, the inner diameter of the tubular housing component in this region matches the outer diameter of the edges of the contact element, particularly the outer diameter of the metal disc, and the seal is pulled inward.

[0075] In the case of contact elements where the seal is stretched and rests on the edge, cell closure can be achieved by beading or crimping, which involves compressing the seal.

[0076] The seal itself may be a standard polymer seal that should be chemically resistant to the electrolyte used in any case. Those skilled in the art will recognize suitable sealing materials.

[0077] The effect of the first modification for closure is that the contact elements are electrically insulated from the tubular housing component. The contact elements form the electrical terminals of the cell. In the case of closure according to the second modification for closure, the tubular housing component and the contact elements have the same polarity.

[0078] In the second closure variant, the weld seam is preferably formed by welding the edges of the contact elements to the tubular housing component using a laser. Alternatively, the metal disc can be secured by soldering or adhesive bonding, in principle. In the latter case, the contact elements can be electrically insulated from the tubular housing component, as is the case when using a seal.

[0079] Welding of the contact element to one of the first longitudinal edges The concept of welding the edge of a current collector to a contact element is already known from International Publication No. 2017 / 215900A1 or Japanese Patent Publication No. 2004-119330A. This technique enables particularly high current tolerance and low internal resistance. Regarding methods for electrically connecting contact elements, and especially disk-shaped contact elements, to the edge of a current collector, the contents of International Publication No. 2017 / 215900A1 and Japanese Patent Publication No. 2004-119330A are fully referenced.

[0080] In this case, the contact of the first longitudinal edge with respect to the contact element or its components results in a linear contact zone, which extends spirally in the case of a spirally wound electrode. Along this linear and preferably spirally shaped contact zone, or in a direction transverse thereto, it is possible to maximize the uniformity of the attachment of the longitudinal edge to the contact element or its components using a suitable welded joint.

[0081] Deformed form of a housing with a housing cup In a particularly preferred embodiment of the present invention, the energy storage cell has at least one of the following features a. and b.: a. The tubular housing component is part of the housing cup, which has a circular base. b. The other of the first longitudinal edges is directly adjacent to the base and is preferably joined to the base by welding. The realization of the combination of the preceding features a. and b. is particularly preferable.

[0082] This modification is particularly suitable for cells using the first modification for closure described above. When the second modification for closure is used, terminal bushings are required, except in the case of the adhesive bond described above.

[0083] The use of housing cups has long been known in the construction of cell housings, for example, from the International Publication No. 2017 / 215900A1 quoted at the beginning. In contrast, what is unknown is the direct attachment of the longitudinal edge of the current collector to the bottom of the housing cup, as proposed herein.

[0084] According to the present invention, it is preferable that the current collector edges of the positive and negative electrodes, which protrude from the end faces on both sides of the winding-shaped electrode-separator assembly, be directly coupled to the housing component, i.e., the bottom of the cup and the contact element that functions as the closing element described above. Therefore, using the available internal volume of the cell housing for the active ingredient approaches its theoretically optimal condition.

[0085] The connection of the other of the first longitudinal edges to the base or contact sheet basically follows the same construction principle as the connection of the first longitudinal edge to the contact element. Here, the longitudinal edge is adjacent to the base or contact sheet, thereby similarly resulting in a spirally extending linear contact zone in the case of a spirally wound electrode. Along this linear and preferably spirally shaped contact zone, or in a direction transverse thereto, it is possible to maximize the uniformity of the attachment of the longitudinal edge to the base using a suitable welded joint.

[0086] Modified form of a housing with two covers In a further particularly preferred embodiment of the present invention, the energy storage cell has at least one of the following three features a. to c.: a. The tubular housing component has a further terminal circular opening. b. The cell comprises a closing element having a circular edge that closes this further tunnel opening. c. A closing element for a further terminal opening is a metal disk or comprises a metal disk, the edge of which corresponds to or forms a portion of the circular edge of the metal closing element. The realization of a combination of the preceding features a. to c. is particularly preferable.

[0087] In this embodiment, the tubular housing component, together with the closing element, forms a housing cup. Thus, the housing consists of three housing components, one of which is tubular, and the other two (contact element and closing element) close the terminal opening of the tubular portion. From a manufacturing standpoint, this method offers the advantage that, unlike the case of a housing cup, it does not require deep drawing tools for manufacturing the tubular housing component. If the other of the first longitudinal edge is directly attached to the closing element, this essentially provides the same advantages as the case of attaching the housing cup to the base described above.

[0088] In this embodiment, the tubular housing component is preferably cylindrical or hollow cylindrical. In the simplest embodiment, the closing element is a metal disk having a circular circumference. More preferably, the metal disk of the closing element may be formed similarly to the metal disk of the contact element.

[0089] In some preferred embodiments, the closing element, in particular the metal disk, may have edges that are curved radially inward, resulting in the closing element having a double-layered edge region having, for example, a U-shaped cross-section.

[0090] In further embodiments, the closing element, particularly the metal disc, may have an edge that is bent at 90° to have an L-shaped cross-section.

[0091] In one particularly preferred embodiment, the energy storage cell has at least one of the following features a. to c.: a. The metal disc of the closing element, or the metal disc forming the closing element, is positioned within the tubular housing component such that its edge extends along the circumferential contact zone inside the tubular housing component. b. The edges of the metal disc are joined to the tubular housing component via circumferential weld seams. c. The tubular housing component includes a circular edge that is bent radially inward around the edge of the closing element, particularly around the edge of the metal disk. More preferably, features a. and b. described above, and, where appropriate, features a. to c. described above, are realized in combination.

[0092] Therefore, in this advanced form, it is preferable to fix the closing element by welding it into an additional terminal opening. Again, in the case of a circumferential weld seam, a separate sealing element is not required.

[0093] This variant is particularly preferred when the cell is closed according to the modified form of the first closure described above.

[0094] While radially bending the edges of a closing element is an optional measure not required for its fixation, it can still be appropriate in some cases.

[0095] In one developmental form, the energy storage cell has one of the following features a. and b.: a. The other of the first longitudinal edges is directly adjacent to the metal disk of the closure element, or the metal disk forming the closure element, and is preferably joined to the metal disk by welding. b. The other of the first longitudinal edges is welded to a contact sheet directly adjacent to the metal disk.

[0096] In principle, as with the contact element, it is possible here that only an indirect connection exists between the other longitudinal edge of the first longitudinal edge and the metal disk or closing element via a contact sheet. In this case, preferably, there is a direct connection by direct welding between the contact sheet and the closing element, particularly the metal disk of the closing element. Here, the contact sheet may be configured as the corresponding part in the case of the contact element described above.

[0097] Here again, the coupling of the other of the first longitudinal edges to the metal disk or to the contact sheet of the closure element basically follows the same construction principle as in the case of coupling the first longitudinal edge to the contact element. The longitudinal edge is adjacent to the metal disk or contact sheet, thereby providing a spirally extending linear contact zone in the case of a spirally wound electrode. Along this linear and preferably spirally shaped contact zone, or in a direction transverse thereto, it is possible to maximize the uniformity of the attachment of the longitudinal edge to the metal disk or to the contact sheet of the closure element using a suitable welded joint.

[0098] Housing materials In particular, when the cell of the present invention is configured as a lithium-ion battery, the selection of materials for manufacturing the housing cup, metal disk and / or contact sheet, and the closure element or its components depends on whether the anode current collector or the cathode current collector is mounted to the corresponding housing component. Preferred materials are, in principle, the same as the materials used to manufacture the current collector itself. Therefore, the aforementioned housing component may be composed of, for example, the following materials: Alloy aluminum or non-alloy aluminum, alloy titanium or non-alloy titanium, alloy nickel or non-alloy nickel, alloy copper or non-alloy copper, stainless steel (e.g., type 1.4303 or 1.4404), nickel-plated steel.

[0099] In addition, the housing and its components may be made of multilayer material ("clad material"), for example, one layer of steel and one layer of aluminum or copper. In these cases, the aluminum layer or copper layer forms, for example, the inside of the housing cup or the base of the housing cup. Even more suitable materials are known to those skilled in the art.

[0100] Preferred electrode configuration In the free-edge strip, the metal of the corresponding current collector preferably does not contain the corresponding electrode material. In some preferred embodiments, the metal of the corresponding current collector is not covered in the free-edge strip, and as a result, the free-edge strip is available for connections involving electrical contact by welding to, for example, a contact element or a closing element.

[0101] In some further embodiments, the metal of the corresponding current collector in the free edge strip may instead be coated in at least some areas with a support material that is more thermally stable than the material coating the current collector and is different from the electrode material placed on the corresponding current collector.

[0102] In this specification, "higher thermal stability" means that the support material remains in a solid state at the temperature at which the current collector metal melts. Therefore, the support material either has a higher melting point than the metal, or the support material sublimes or decomposes only at the temperature at which the metal has already melted.

[0103] In connection with the present invention, the support material can, in principle, be a metal or metal alloy having a higher melting point than the metal constituting the surface coated with the support material. However, in many embodiments, the energy storage cell of the present invention preferably has at least one of the following features a. to d.: a. The supporting material is a non-metallic material. b. The supporting material is an electrical insulating material. c. Nonmetallic materials are ceramic materials, glass ceramic materials, or glass. d. Ceramic materials include aluminum oxide (Al2O3), titanium oxide (TiO2), titanium nitride (TiN), titanium aluminum nitride (TiAlN), silicon oxide, especially silicon dioxide (SiO2), or titanium carbonitride (TiCN).

[0104] According to the present invention, the support material more preferably conforms to the preceding feature b., and particularly preferably conforms to the preceding feature d.

[0105] The term "non-metallic materials" includes, among other things, plastics, glass, and ceramic materials.

[0106] In relation to this specification, the term "electrical insulating material" should be interpreted broadly. In principle, electrical insulating material encompasses any electrical insulating material, including polymers in particular.

[0107] In the context of this specification, the term "ceramic material" should be interpreted broadly. Specifically, ceramic material is understood to mean carbides, nitrides, oxides, silicides, or mixtures and derivatives of these compounds.

[0108] The term "glass ceramic material" specifically refers to materials containing crystalline particles embedded in an amorphous glass phase.

[0109] The term "glass" generally refers to any inorganic glass that meets the thermal stability criteria defined above and is chemically stable to any electrolyte present in the cell.

[0110] More preferably, the anode current collector is made of copper or a copper alloy, while the cathode current collector is made of aluminum or an aluminum alloy, and the support material is aluminum oxide or titanium oxide.

[0111] It may be even more preferable that the free edge strips of the anode current collector and / or cathode current collector are coated with a strip of support material.

[0112] The main regions, particularly the strip-shaped main regions of the anode and cathode current collectors, preferably extend parallel to the corresponding edges or longitudinal edges of the current collectors. Preferably, the strip-shaped main regions extend over at least 90%, more preferably at least 95%, of the area of ​​the anode and cathode current collectors.

[0113] In some preferred embodiments, the support material is preferably applied in a strip-like or linear manner along the main strip-like region, but does not completely cover the exposed region, and as a result, the metal of the corresponding current collector is directly exposed along its longitudinal edge.

[0114] Other preferred configurations of energy storage cells The energy storage cell of the present invention may be a button cell. The button cell is cylindrical and has a height smaller than its diameter. The height is preferably in the range of 4 mm to 15 mm. It is more preferable that the button cell has a diameter in the range of 5 mm to 25 mm. The button cell is suitable for supplying electrical energy to small electronic devices such as watches, hearing aids, and wireless headphones.

[0115] The nominal capacity of the button battery of the present invention in the form of a lithium-ion battery is generally up to 1500mAh. The nominal capacity is preferably in the range of 100mAh to 1000mAh, more preferably in the range of 100 to 800mAh.

[0116] However, more preferably, the energy storage cell of the present invention is a cylindrical circular cell. The cylindrical circular cell has a height greater than its diameter. The cylindrical circular cell is particularly suitable for the high-energy applications mentioned at the beginning, for example, in the automotive sector, or for electric bicycles, or for power tools.

[0117] The height of a circular energy storage cell is preferably in the range of 15 mm to 150 mm. The diameter of a cylindrical circular cell is preferably in the range of 10 mm to 60 mm. Within these ranges, shape factors of, for example, 18 × 65 (diameter × height in mm), 21 × 70 (diameter × height in mm), 32 × 700 (diameter × height in mm), or 32 × 900 (diameter × height in mm) are particularly preferred. Cylindrical circular cells having these shape factors are particularly suitable for supplying power to electric drive units in automobiles.

[0118] The nominal capacity of the cylindrical circular cell of the present invention in the form of a lithium-ion battery is preferably up to 90,000 mAh. In the case of a 21 × 70 shape factor, the cell in one embodiment as a lithium-ion battery preferably has a nominal capacity in the range of 1,500 mAh to 7,000 mAh, more preferably in the range of 3,000 to 5,500 mAh. In the case of an 18 × 65 shape factor, the cell in one embodiment as a lithium-ion battery preferably has a nominal capacity in the range of 1,000 mAh to 5,000 mAh, more preferably in the range of 2,000 to 4,000 mAh.

[0119] In the European Union, manufacturer information regarding the nominal capacity of rechargeable batteries is strictly regulated. For example, information regarding the nominal capacity of rechargeable nickel-cadmium batteries is based on measurements according to the IEC / EN 61951-1 and IEC / EN 60622 standards, information regarding the nominal capacity of rechargeable nickel-metal hydride batteries is based on measurements according to the IEC / EN 61951-2 standard, information regarding the nominal capacity of rechargeable lithium batteries is based on measurements according to the IEC / EN 61960 standard, and information regarding the nominal capacity of rechargeable lead-acid batteries is based on measurements according to the IEC / EN 61056-1 standard. Any drawings relating to nominal capacity in this invention are preferably also based on these standards.

[0120] In embodiments of the present invention where the cell is a cylindrical circular cell, the anode current collector, cathode current collector, and separator are preferably ribbon-shaped and preferably have the following dimensions: • Lengths ranging from 0.5m to 25m • Width range of 30mm to 145mm. In this case, the free edge strip extending along the first longitudinal edge and not provided with electrode material preferably has a width of 5000 μm or less.

[0121] In the case of a cylindrical circular cell having a shape factor of 18 × 65, the current collector preferably has the following: • A width of 56mm to 62mm, preferably 60mm, and • A length of 2m or less, preferably 1.5m or less.

[0122] In the case of a cylindrical circular cell having a shape factor of 21 × 70, the current collector preferably has the following: • A width of 56mm to 68mm, preferably 65mm, and • A length of 3m or less, preferably 2.5m or less.

[0123] In a particularly preferred embodiment of the present invention, the energy storage cell of the present invention has the following features: a. The contact element is equipped with a safety valve that allows pressure to escape from the housing if it exceeds a further pressure threshold.

[0124] This safety valve may be, for example, a burst membrane, a burst cross, or a similar intended rupture site that can rupture and open at a defined positive pressure in the cell to prevent the cell from exploding.

[0125] More preferably, the metal disc of the contact element may include a safety valve in the form of a particularly intended fracture site.

[0126] Embodiment of a prism Firstly, the use of a contact element that serves as both a housing component and a CID (Central Identifier) ​​component for contact connection to one of the electrodes is not limited to energy storage cells having a cylindrical housing. Rather, an energy storage element having a laminate formed from two or more identical electrode-separator assemblies and surrounded by a prism-shaped housing can also have such a contact element.

[0127] Therefore, the present invention also includes an energy storage element having the following features a. to l.: a. The energy storage element comprises at least two electrode-separator assemblies having an anode / separator / cathode sequence. b. The anodes of the assembly are preferably rectangular, and each comprises an anode current collector having an anode current collector edge. c. Each anode current collector comprises a main region provided with a layer of negative electrode material, and a free edge strip extending along the corresponding anode current collector edge and not provided with electrode material. d. The cathodes of the assembly are preferably rectangular, and each comprises a cathode current collector having a cathode current collector edge. e. Each cathode current collector has a main region provided with a layer of positive electrode material, and a free edge strip that extends along the corresponding cathode current collector edge and is not provided with electrode material. f. At least two electrode-separator assemblies are in a stacked configuration, and the stacked assembly has two terminal portions. g. The electrode-separator assembly is surrounded by a prism-shaped housing. h. The anode and cathode are designed and / or arranged such that the edge of the anode current collector protrudes from one of the terminal portions, and the edge of the cathode current collector protrudes from the other of the terminal portions. i. The energy storage element comprises a metallic contact element that is in direct contact with the edge of the anode current collector or the edge of the cathode current collector. j. The contact elements are joined to the edges by welding and are in direct contact with the edges. k. The contact elements function as components of the housing. l. The contact elements comprise a metal membrane that is electrically connected to the edges, bonded to the contact elements by welding, and bends when the pressure inside the housing exceeds a threshold, resulting in the loss of electrical contact with these edges. With respect to the contact elements and their components, the same preferred forms of development are applicable as in the case of the energy storage cell of the present invention.

[0128] Further features and advantages of the present invention will become apparent from the claims and from the following description of preferred embodiments of the invention in conjunction with the drawings. Each of the features described herein may be realized individually or in combination with each other. [Brief explanation of the drawing]

[0129] [Figure 1] This is a cross-sectional view of a front perspective of the contact element according to the present invention. [Figure 2] This is a partial cross-sectional view of the contact element shown in Figure 1 and the edge of the current collector fixed thereto. [Figure 3] This is a top view of one embodiment of a contact sheet. [Figure 4] This is a top view of one embodiment of a metal disk of a contact element. [Figure 5] This is a diagram (cross-sectional view) of the energy storage cell of the present invention in the third preferred modified embodiment of the present invention described above. [Modes for carrying out the invention]

[0130] Figures 1 and 2 show a contact element 110 comprising a metal disc 111, a metal terminal cover 112, a seal 103, and a spacer element 129. The metal disc 111 and the terminal cover 112 each have a circular circumference. The edge of the terminal cover 112 may be surrounded by the edge of the metal disc 111, which is bent radially inward. The edges of the metal disc 111 and the terminal cover 112 collectively form the edge of the contact element 110. The seal 103 is stretched to cover the edge of the contact element.

[0131] The spacer element closes the opening 161, which can serve to introduce electrolyte into the battery housing. To ensure a liquid-tight seal, the spacer element 129 may be welded or soldered to the metal disc 111 for this purpose.

[0132] The metal disk 111 and terminal cover 112 surround the internal space 116. The metal disk 111 can bend into the internal space 116 when pressure is applied to its underside. In the installed state, its underside faces the inside of the battery housing.

[0133] The internal space 116 is not closed. Instead, the terminal cover 112 has at least one opening 139 that can balance the pressure against the environment of the cell in which the contact element 110 is located. As a result, when the metal disk 111, which functions as a membrane, bends and enters the internal space 116, no back pressure buildup occurs within the internal space 116.

[0134] A spacer element 129 is provided to prevent the metal disk 111 from bending even at pressures below a threshold. Preferably, one end of the spacer element abuts against the metal disk 111 and the other end abuts against the terminal cover 112, preventing the membrane from bending and entering the interior 116 too quickly. For example, the spacer element 129 may be a plastic or metal part that breaks or deforms plastically under a predetermined pressure on the membrane.

[0135] The metal disc 111 has a bead-shaped channel recess 179. The current collector edge 115a is welded in this bead region.

[0136] The contact sheet 113 shown in Figure 3 is star-shaped and comprises a central portion 113a and three strip-like extensions 113b with a star-like configuration. The contact sheet 113 may be welded to the edge of the current collector along a line 113c on the strip-like extensions 113b. The contact sheet may be, for example, punched out from a sheet and is preferably flat.

[0137] The metal disc 111 shown in Figure 4 has three elongated beads 111c intended to improve contact connection to the edge of the current collector. The beads 111c are similarly arranged in a star shape. The metal disc 111 may be welded to the edge of the current collector along the lines within the beads 111c.

[0138] The energy storage cell 100 shown in Figure 5 comprises a hollow cylindrical housing component 101, which is a component of the housing cup 107, having a circular base 107a and a circular opening (defined by a rim 101a). The housing cup 107 is a deep-drawn component. The housing cup 107 surrounds the interior 137 together with the contact element 110, inside which a winding-shaped electrode-separator assembly 104 is axially aligned. The contact element 110 comprises a metal disk 111 having a circular rim and a contact sheet 113.

[0139] The electrode-separator assembly 104 is in the form of a cylindrical winding with two terminal end faces, between which a circumferentially wound jacket extends, adjacent to the inside of the hollow cylindrical housing component 101. The electrode-separator assembly is formed from a positive electrode and a negative electrode, as well as separators 118 and 119, each of which is ribbon-shaped and spirally wound.

[0140] The two end faces 104b and 104c of the electrode-separator assembly 104 are formed by the longitudinal edges of the separators 118 and 119. The current collectors 115 and 125 protrude from these end faces. The corresponding excess lengths are designated as d1 and d2. To ensure that the current collectors 115 and 125 can protrude from the end faces 104b and 104c, the ribbon-shaped anode and ribbon-shaped cathode are in an offset arrangement from each other within the electrode-separator assembly 104.

[0141] The anode current collector 115 protrudes from the upper end surface 104b of the electrode-separator assembly 104, and the cathode current collector 125 protrudes from the lower end surface 104c. In the main region, the strip-shaped anode current collector 115 is provided with a layer of negative electrode material 155. In the main region, the strip-shaped cathode current collector 125 is provided with a layer of positive electrode material 123. The anode current collector 115 has an edge strip 117 extending along its longitudinal edge 115a, which is not provided with the electrode material 155. Instead, a coating 165 of ceramic support material is applied here, thereby stabilizing the current collector in this region. The cathode current collector 125 has an edge strip 121 extending along its longitudinal edge 125a, which is not provided with the electrode material 123. Instead, a coating 165 of ceramic support material is also applied here.

[0142] The edge 115a of the anode current collector 115 is in direct contact with the contact sheet 113 along its entire length and is joined to the contact sheet by welding. Thus, the contact element 110 simultaneously functions as an electrical contact connection for the anode and as a housing component.

[0143] The edge 125a of the cathode current collector 125 is in direct contact with the base 107a along its entire length and is joined to the base by welding. Thus, the base 107a functions not only as a component of the housing but also for the electrical contact connection of the cathode.

[0144] Housing components 101 and 110 are electrically insulated from each other by a seal 103. The edge 101a of housing component 101 is bent radially inward around the edge of the metal disc 111 surrounded by the seal 103, securing the metal disc 111 within the circular opening of the tubular housing component 101. In the axial direction, the tubular housing component 101 comprises a section adjacent to the inside of the tubular housing component by a circumferentially wound jacket 104a, and a contact section adjacent to the inside of the tubular housing component by an annular seal 103. In the contact section, the annular seal 103 is in a compressed form as a result of the pressure applied to the annular seal by the edge 110a of the contact element 110 and the inside of the tubular housing component 101.

[0145] Immediately below the contact section, the housing component 101 has a circumferential bead 133. The bead 133 is not very prominent and protrudes only less than the thickness of the housing wall into the interior 137 on the inside of the housing component 101.

[0146] The metal disk 111 contains a metal membrane 151 in the form of a bistable spring element at its center. The membrane 151 bends inward 137 and contacts the contact sheet 113. When the pressure in the interior 137 exceeds a threshold, the membrane 151 bends outward, and the electrical connection between the metal disk 111 and the contact sheet 113 is broken. To ensure that electrical contact between the metal disk 111 and the contact sheet 113 is possible only through the membrane 151, the contact element 110 further comprises a spacer 189. The spacer is a plastic ring.

[0147] To ensure that the space defined by the spacer 189, contact sheet 113, and metal disk 111 is in communication connection with the interior 137, the contact sheet 113 is provided with a hole 187.

Claims

1. An energy storage cell (100) having the following characteristics: a. The cell comprises an electrode-separator assembly (104) having an anode / separator / cathode sequence. b. The electrode-separator assembly (104) takes the form of a cylindrical winding having two terminal end faces (104b, 104c) and a wound jacket (104a). c. The cell comprises a housing that includes a metal tubular housing component (101) having a terminal circular opening (101c), d. The electrode-separator assembly (104), which takes the form of a winding, is aligned axially within the housing such that the wound jacket (104a) is adjacent to the inside (101b) of the tubular housing component (101). e. The anode is ribbon-shaped and comprises a ribbon-shaped anode current collector (115) having a first longitudinal edge (115a) and a second longitudinal edge. f. The anode current collector (115) comprises a strip-shaped main region having a layer of negative electrode material (155), and a free edge strip (117) extending along the first longitudinal edge (115a) and not having the negative electrode material (155). g. The cathode is ribbon-shaped and comprises a ribbon-shaped cathode current collector (125) having a first longitudinal edge (125a) and a second longitudinal edge. h. The cathode current collector (125) comprises a strip-shaped main region having a layer of positive electrode material (123), and a free edge strip (121) extending along the first longitudinal edge (125a) and not having the positive electrode material (123). i. The anode and the cathode are formed and / or arranged within the electrode-separator assembly (104) such that the first longitudinal edge (115a) of the anode current collector (115) extends beyond one of the terminal end faces (104b, 104c) and the first longitudinal edge (125a) of the cathode current collector (125) extends beyond the other of the terminal end faces (104b, 104c). j. The cell comprises a contact element (110) which is at least partially metallic, and which is in direct contact with one of the first longitudinal edges (115a, 125a) and is welded to the longitudinal edge. And the following additional distinctive features: k. The contact element (110) has a circular edge (110a) and closes the terminal circular opening (101c) of the tubular housing component (101) in an airtight and liquid-tight manner. l. The contact element (110) is electrically connected to one of the first longitudinal edges (115a, 125a) and is a metal membrane (111, 151) that bends when the pressure inside the housing exceeds a threshold, resulting in a loss of electrical contact of the contact element with the first longitudinal edges (115a, 125a), or includes the same. m. The contact element (110) includes a metal disc (111) as the metal membrane (111), and further includes a contact sheet (113), and n. The contact sheet (113) is in direct contact with one of the first longitudinal edges (115a, 125a) and is joined to the longitudinal edge by welding. An energy storage cell (100) having [a certain feature].

2. The following additional features: a. The contact element (110) comprises, as a membrane, the metal disk (111) and further, a terminal cover (112), each having a circular circumference. b. The metal disc (111) is in direct contact with one of the first longitudinal edges (115a, 125a) and is joined to the longitudinal edge by welding. c. The metal disk (111) and the terminal cover (112) surround the internal space (116), and when the threshold is exceeded, the metal disk (111) bends into the internal space. d. At least one spacer element (129) is disposed within the internal space (116), which prevents bending into the internal space (116) when the threshold is below the threshold and collapses and / or compresses when the threshold is exceeded. An energy storage cell according to claim 1, having the following features.

3. The following additional features: a. The metal disk (111) has at least one channel and / or dot-shaped recess (179) on one side thereof, the recess protruding as at least one linear and / or dot-shaped ridge on the other side thereof. b. The metal disk (111) has a side surface having at least one ridge adjacent to one of the first longitudinal edges (115a, 125a), c. At least one of the ridges and the first longitudinal edges (115a, 125a) are joined via at least one welding point and / or at least one welding seam. The energy storage cell according to claim 2, having at least one of the following.

4. The following additional features: a. The metal disk (111) has a plurality of channel-shaped depressions (179) on one side surface, and these depressions protrude as linear ridges on the other side surface. b. The metal disc (111) has at least one weld seam in each of the channel-shaped recesses (179) as a result of welding the metal disc (111) to one of the first longitudinal edges (115a, 125a). An energy storage cell according to claim 3, having the following features.

5. The following additional features: c. The contact sheet (113) is star-shaped and comprises a central portion 113a and at least three strip-shaped extensions 113b having a star-shaped configuration. d. The metal disk (111) has a star-shaped recess on one of its sides in addition to the channel-shaped recess (179), and the contact sheet (113) is located within the star-shaped recess. e. At least one insulating means disposed between the metal disk (111) and the contact sheet (113) insulates the strip-shaped extension from the metal disk. f. The central portion of the metal disc (111) and the contact sheet (113) are directly joined to each other by welding. The energy storage cell according to claim 4, having at least one of the following.

6. The following additional features: a. The contact element (110) comprises a metal disc (111) as a membrane, and further a terminal cover (112), each having a circular circumference. b. The contact element (110) includes a contact sheet (113) that is in direct contact with one of the first longitudinal edges (115a, 125a) and is joined to the longitudinal edge by welding. c. The metal disk (111) and the terminal cover (112) surround the internal space (116), and when the threshold is exceeded, the metal disk (111) bends into the internal space. d. At least one spacer element (129) is disposed within the internal space (116), which prevents bending into the internal space (116) when it falls below the threshold and collapses and / or compresses when it exceeds the threshold. e. The metal disc (111) and the contact sheet (113) are directly joined to each other by welding. An energy storage cell according to claim 1, having the following features.

7. The following additional features: a. The contact element (110) comprises a metal disc (111) having a circular circumference and a contact sheet (113). b. The contact sheet (113) is in direct contact with one of the first longitudinal edges (115a, 125a) and is joined to the longitudinal edge by welding. c. The metal disk (111) and the contact sheet (113) are separated from each other by at least one electrically insulated spacer (189). d. The metal disk (111) comprises the metal membrane (151), or is formed as the membrane (151) in some areas. e. The membrane (151) is in electrical contact with the contact sheet (113) until the threshold is exceeded. An energy storage cell according to claim 1, having the following features.

8. The following additional features: a. When the threshold is exceeded, the membrane (151) takes the form of a spring element that changes from a first stable state to a second stable or metastable state. An energy storage cell according to claim 7, having the following features.

9. The following additional features: a. The contact element (110) comprises, in addition to the metal disk (111), a terminal cover (112) having a circular circumference. b. The metal disk (111) and the terminal cover (112) surround the internal space (116), and when the threshold is exceeded, the membrane (151) bends into the internal space. An energy storage cell according to claim 7 or 8, having the following features.

10. The following additional features: a. The cell comprises an annular seal (103) made of an electrically insulating material surrounding the circular edge (110a) of the contact element (110), b. The contact element (110) is positioned within the tubular housing component (101) together with the seal (103) such that the annular seal (103) is adjacent to the inside (101b) of the tubular housing component (101) along the circumferential contact zone, and the contact element (110) together with the seal (103) seals the terminal circular opening (101c) of the tubular housing component (101). An energy storage cell according to any one of claims 1 to 9, comprising:

11. The following additional features: a. The contact element (110) is positioned within the tubular housing component (101) such that its circular edge (110a) extends along the circumferential contact zone on the inside (101b) of the tubular housing component (101). b. The circular edge portion (110a) of the contact element (110) is joined to the tubular housing component (101) via a circumferential welding seam (101). An energy storage cell according to any one of claims 1 to 9, comprising:

12. The following additional features: a. The contact element (110) is equipped with a safety valve that allows pressure to escape from the housing if a further pressure threshold is exceeded. An energy storage cell according to any one of claims 1 to 11, comprising:

13. The following additional features: a. The metal membrane (111; 151) takes the form of a spring element that changes from a first stable state to a second stable or metastable state when the threshold is exceeded. An energy storage cell according to claim 1, having the following features.

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