Electrochemical cell and method of manufacturing the same

Abstract

The electrochemical cell (100) comprises an electrode-separator composite (101) having an anode (115), at least one separator (116, 117), and a cathode (118); the anode comprises an anode current collector (115a) made of at least one metal and having a surface laminated with at least one layer (115b) of a cathode active electrode material; the cathode comprises a cathode current collector (118a) made of at least one metal and having a surface laminated with at least one layer (118b) of a cathode active electrode material; the surface of the anode current collector and / or the surface of the cathode current collector comprises at least one clear area (115c; 118c) that is not laminated with the respective active electrode material; and in at least one clear area, the surface of the anode current collector and / or the surface of the cathode current collector is coated with a support material (119) having a thermal stability greater than the thermal stability of the coated surface.

Description

[Technical Field]

[0001] The invention described below relates to an electrochemical cell having an electrode-separator composite that includes an anode, at least one separator, and a cathode. [Background technology]

[0002] This type of cell is already known in principle, for example from DE 10 2009 060 800 A1. This German patent application describes a cylindrical winding of an electrode-separator composite inserted into a cylindrical metal housing. The electrodes are electrically contacted using current collectors laminated with the active electrode material. The current collectors are welded to metal foils that each function as a separate electrical conductor and electrically contact the current collectors to the housing.

[0003] The method described in DE 10 2009 060 800 A1 for electrical contact connection of electrodes is efficient and inexpensive. However, it has drawbacks in certain applications. One problem is the electrical connection of electrodes, for example, via metal foil. If a high current is stored or released in a short time by an electrode connected in this way, the metal foil will heat up significantly.

[0004] WO 2017 / 215900 A1 discloses an electrochemical cell of the general type in which the electrode-separator composite and its electrodes are in the form of strips and in the form of a winding or stack. Each electrode has a current collector laminated with electrode material. The electrodes of opposite polarity are offset from one another within the electrode-separator composite, with the longitudinal edge of the anode current collector protruding from the winding or stack on one side and the longitudinal edge of the cathode current collector protruding from the winding or stack on the other side. The current collectors are electrically contacted by a cell having at least one contact plate adjacent to one of the longitudinal edges in a manner that provides a linear contact area. The contact plate is joined to the longitudinal edge by welding along the linear contact area. This allows electrical contact to the current collector, and therefore the corresponding electrode, over its entire length. This significantly reduces the internal resistance within the cell. As a result, large currents can be handled much better than with the cell known from DE 10 2009 060 800 A1, for example.

[0005] However, a problem with the cell described in WO 2017 / 215900 A1 is that it is extremely difficult to weld the longitudinal edges and contact plates together. The current collectors of the electrodes have a significantly smaller thickness than the contact plates. Therefore, the edge regions of the current collectors are very mechanically sensitive and can be unintentionally compressed or melted during the welding operation. Furthermore, melting of the separator of the electrode-separator composite can occur when the contact plate is welded onto it. In extreme cases, this can result in a short circuit. Summary of the Invention

[0006] The object of the present invention is to provide an electrochemical cell of the general type which not only has improved current-carrying capacity but also has improved productivity compared to the cited prior art.

[0007] To this end, the invention proposes an electrochemical cell having the features of claim 1 and a method having the features of claim 13. Developments of the invention are the subject matter of the dependent claims. All claim terms are incorporated herein by reference. The electrochemical cell of the present invention has the following characteristics (a) to (d): (a) an electrochemical cell comprising an electrode-separator composite, the electrode-separator composite having an anode, at least one separator, and a cathode; (b) the anode includes an anode current collector, the anode current collector comprising at least one metal and having a surface coated with at least one layer of cathode active electrode material; (c) the cathode includes a cathode current collector, the cathode current collector being comprised of at least one metal and having a surface coated with at least one layer of anode active electrode material; (d) the surface of the anode current collector and / or the surface of the cathode current collector includes at least one clear area that is not covered with the respective active electrode material.

[0008] The cells have the following characteristics in particular: (e) In at least one clear region, the surface of the anode current collector and / or the surface of the cathode current collector are coated with a support material, and the thermal stability of the support material is greater than the thermal stability of the coated surface.

[0009] By "greater thermal stability" herein is meant that the support material remains in a solid state at the temperature at which the surface melts, and therefore either has a higher melting point than the surface, or does not sublime or decompose up to the temperature at which the surface has already melted.

[0010] Preferably, both the surface of the anode current collector and the surface of the cathode current collector have clear areas that are not coated with the respective active electrode material. In one development, it is preferred that both the clear areas on the surface of the anode current collector and the clear areas on the surface of the cathode current collector are coated with a support material. It is particularly preferred to use the same support material for each of the areas.

[0011] The cells of the present invention are preferably secondary, i.e., rechargeable, cells. Therefore, the active electrode materials useful for the cells of the present invention preferably include materials that can be used in secondary electrochemical cells.

[0012] More preferably, the electrochemical cell is a lithium-ion cell. Useful active electrode materials in this case are all materials capable of absorbing lithium ions and releasing them again. The cathode active electrode material can be a carbon-based material, such as graphitic carbon, or another material capable of lithium ion intercalation. Metals and semimetals capable of forming intermetallic phases with lithium, such as silicon, can also be used as cathode electrode materials, especially in mixtures with carbon-based materials capable of lithium ion intercalation. Examples of useful anode active electrode materials include lithium metal oxide compounds and lithium metal phosphate compounds, such as LiCoO2 and LiFePO4. Further suitable materials include those based on NMC (lithium nickel manganese cobalt oxide), LTO (lithium titanate), and NCA (lithium nickel cobalt aluminum oxide).

[0013] In a further preferred embodiment, the cell of the present invention can be a nickel metal hydride cell having a hydrogen storage alloy as the active electrode material on the cathode side and nickel hydroxide / nickel oxyhydroxide on the anode side.

[0014] Furthermore, the electrodes in the cell of the present invention can be designed like the electrodes of the systems described in WO2016 / 005529A1 and WO2016 / 005528A2, which describe systems in which the anode comprises an active electrode material based on nickel oxyhydroxide / nickel hydroxide and the cathode comprises as active electrode material a mixture of activated carbon and a hydrogen storage alloy or a mixture of activated carbon and iron in metallic and / or oxidized form.

[0015] In all the above cases, the active electrode material on both the anode and cathode sides is preferably in particulate form.

[0016] In addition to the active electrode material and current collector, the electrodes of the cells of the present invention may also have further components. In particular, these are generally electrode binders and conductors. The electrode binder ensures the mechanical stability of the electrode and ensures electrical and mechanical contact of the active electrode material particles with each other and with the current collector. Conductors such as carbon black have the role of increasing the electrical conductivity of the electrode.

[0017] Generally, the electrode-separator composite contains an electrolyte with which the electrodes are impregnated, the electrolyte ensuring ionic flow between the electrodes of the cell during charging or discharging of the cell. In the case of lithium-ion batteries, the electrolyte used is usually a mixture of organic carbonates containing an electrically conductive lithium salt. In the case of nickel metal hydride cells and the cells described in WO 2016 / 005529 A1 and WO 2016 / 005528 A2, the electrolyte used is preferably an aqueous alkaline solution.

[0018] At least one separator serves to prevent direct contact between electrodes of opposite polarity. At the same time, it must be permeable to ions that migrate back and forth between the electrodes during charge and discharge operations. Separators useful for the electrode-separator composite of the cell of the present invention include separators made of porous polymer films, such as polyolefins or polyether ketones. It is also possible to use nonwoven or woven fabrics made of these materials.

[0019] Generally, the electrode-separator composite comprises an electrode and at least one separator in the order anode / separator / cathode. In a preferred embodiment, the composite is in the form of two separators, for example, the order can be cathode / first separator / anode / second separator or anode / first separator / cathode / second separator.

[0020] In some embodiments, the electrode-separator composite may also have more than one anode or more than one cathode. For example, the composite may have the following order: cathode / first separator / anode / second separator / cathode, or anode / first separator / cathode / second separator / anode.

[0021] In the composite, the electrodes and separators are preferably connected by lamination and / or adhesive bonding.

[0022] The current collector in the electrode serves to make maximum area electrical contact with the active electrode material.

[0023] More preferably, the current collector of the cell of the invention, and thus the cell of the invention itself, has at least one of the additional features (a) through (f) immediately below: (a) the at least one metal constituting the surface of the anode current collector comprises at least one metal selected from the group consisting of copper, copper alloy, titanium, titanium alloy, nickel, nickel alloy, and stainless steel; (b) the anode current collector comprises at least one metal; (c) the anode current collector is a metal foil, a metal sponge, a fiber cloth, or an expanded metal; (d) the at least one metal constituting the surface of the cathode current collector comprises at least one metal selected from the group consisting of aluminum, aluminum alloy, titanium, titanium alloy, and stainless steel; (e) the cathode current collector comprises at least one metal; (f) The cathode current collector is a metal foil, a metal sponge, a fiber cloth, or an expanded metal.

[0024] In a preferred embodiment, all of the immediately preceding features (a)-(c) are implemented simultaneously in combination with one another. In a more preferred embodiment, all of the immediately preceding features (d)-(f) are implemented simultaneously in combination with one another. In a particularly preferred embodiment, all of the immediately preceding features (a)-(f) are implemented simultaneously in combination with one another.

[0025] More preferably, the anode current collector consists of copper or a copper alloy, and the cathode current collector consists of aluminum or an aluminum alloy.

[0026] However, it is entirely possible to use current collectors in which a surface made of at least one metal surrounds a non-metallic structure, for example a textile fabric made of glass or plastic filaments, as well as current collectors which consist entirely of at least one metal. The term "textile fabric" here includes in particular nonwoven fabrics, woven fabrics, meshes and knits.

[0027] In a particularly preferred embodiment, the cathode current collector is made of aluminum foil, preferably having a thickness in the range of 5 μm to 30 μm, and more preferably, the anode current collector is made of copper foil, preferably having a thickness in the range of 5 μm to 15 μm, or nickel foil, preferably having a thickness in the range of 3 μm to 10 μm.

[0028] In particularly preferred embodiments, the current collector of the cell of the invention, and thus the cell of the invention itself, has at least one of the additional features (a) to (d) immediately below: (a) an anode current collector having two flat sides separated from each other by at least one edge; (b) an anode current collector having at least one layer of cathode active electrode material laminated on two flat sides thereof; (c) the surface of the anode current collector includes a clear area coated with a support material and divided into two subareas on its two flat sides; (d) Two sub-regions of the anode current collector are coated with a support material.

[0029] More preferably, all of the immediately above features (a)-(d) are implemented simultaneously in combination with one another.

[0030] In particularly preferred embodiments, the current collector of the cell of the invention, and thus the cell of the invention itself, has at least one of the additional features (a) to (d) immediately below: (a) the cathode current collector has two flat sides separated from each other by at least one edge; (b) a cathode current collector having at least one layer of anode active electrode material laminated on two flat sides thereof; (c) the surface of the cathode current collector comprises a clear area coated with a support material and divided into two subareas on its two flat sides; (d) Two sub-regions of the cathode current collector are coated with a support material.

[0031] More preferably, all of the immediately above features (a)-(d) are implemented simultaneously in combination with one another.

[0032] The clear areas or sub-areas can be wholly or partly covered with support material. In contrast, at least one edge separating the flat sides and thus the two sub-areas from each other is preferably not covered with support material.

[0033] In one development, both the cathode current collector and the anode current collector have the aforementioned flat side and a clear area covered with a support material, which is divided into two sub-areas. This is particularly true when the cathode current collector and the anode current collector are each a foil or another of the aforementioned substrates, such as the aforementioned fiber fabric. In the case of such substrates, the surface area of ​​the current collector essentially corresponds to the area of ​​the two flat sides. At least one edge can be ignored in the quantitative calculation of the surface. Due to the small thickness of the aforementioned substrates, it is generally not included in the relative proportion of the surface of the current collectors.

[0034] More preferably, two sub-regions on the cathode current collector and two sub-regions on the anode current collector are coated with a support material.

[0035] More preferably, it is not only at least one clear area on the surface of the anode current collector and / or the surface of the cathode current collector that is coated with the support material, but also the layers of anode and cathode material. For processing reasons, it is easier to apply the support material to both the at least one clear area and the layers of electrode material than to apply the support material only to the at least one clear area, because in the latter case, masking of the layers of electrode material is not required.

[0036] Support materials that can be used in the context of the present invention can in principle be metals or metal alloys, provided that they have a higher melting point than the metal that constitutes the surface coated with the support material. However, in many embodiments, it is preferred that the cells of the present invention have at least one of the additional features (a) to (c) immediately below. (a) the support material is a non-metallic material; (b) the non-metallic material is a ceramic material, a glass-ceramic material, or a glass; (c) The ceramic material is aluminum oxide (Al2O3), titanium oxide (TiO2), titanium nitride (TiN), aluminum titanium nitride (TiAlN), or titanium carbonitride (TiCN).

[0037] The term "ceramic material" in this context should be interpreted broadly. It is understood to mean in particular carbides, nitrides, oxides, silicides, or mixtures and derivatives of these compounds. More preferably, according to the invention, the support material takes the form according to characteristic (c) immediately above.

[0038] The term "glass-ceramic material" especially refers to a material that contains crystalline particles embedded in an amorphous glass phase.

[0039] The term "glass" means, in principle, an inorganic glass that satisfies the criteria of thermal stability defined above and is chemically stable towards the electrolyte present in the cell.

[0040] More preferably, the anode current collector consists of copper or a copper alloy, the cathode current collector simultaneously consists of aluminum or an aluminum alloy, and the support material is aluminum oxide or titanium oxide. In a first particularly preferred variant of the cell of the invention, it has at least one of the additional features (a) to (g) immediately below: (a) the electrode-separator composite is in the form of a roll having two end faces; (b) the electrode-separator composite and at least one separator therein, the electrode and anode current collector and cathode current collector therein are in the form of strips, each having two longitudinal edges; (c) two end faces of the electrode-separator composite are formed by longitudinal edges of at least one separator; (d) both the surface of the anode current collector and the surface of the cathode current collector include clear areas that are not coated with active electrode material; (e) the clear area on the surface of the anode current collector is a strip-shaped edge area along one of its two longitudinal edges; (f) the clear area on the surface of the cathode current collector is an edge area in the form of a strip along one of its two longitudinal edges; (g) an anode in strip form and a cathode in strip form are arranged offset from one another within the electrode-separator composite; a longitudinal edge of the anode current collector protruding from one of the two end faces together with a clear area of ​​the anode current collector; A longitudinal edge of the cathode current collector projects from the other of the two end faces along with a clear area of ​​the cathode current collector.

[0041] Preferably, all of the immediately above features (a)-(g) are implemented simultaneously in combination with each other.

[0042] Even in this rolled configuration of the electrode-separator composite, the current collector preferably has two flat sides, each side laminated with a layer of the respective electrode material. More preferably, both the edge region on the surface of the anode current collector and the edge region on the surface of the cathode current collector are divided by respective longitudinal edges, along which these edge regions extend into two subregions, each in the form of a strip, and all of these edge regions are coated with the support material. More preferably, each subregion is coated with a strip of the support material. The current collector in this case is not laminated with the respective electrode material on both sides, but is coated with the support material on both sides. It is preferred that the longitudinal edges are not coated with the support material.

[0043] In the manufacture of electrode-separator composites, it is usually ensured that the electrode and current collector are assembled together without any protrusions on one side of the current collector of the opposite polarity, as this could increase the risk of short circuits. However, in the case of the offset arrangement described above, the risk of short circuits is minimized, as the current collectors of the opposite polarity protrude from the mutually facing end faces of the windings.

[0044] The windings preferably have a maximum height in the range of 30 mm to 100 mm and a maximum diameter in the range of 10 mm to 45 mm.

[0045] The anode and cathode current collectors in strip form preferably have a length in the range of 50 mm to 300 cm, a width in the range of 30 mm to 100 mm, and a thickness in the range of 30 μm to 200 μm.

[0046] The strip-shaped border regions and strip-shaped sub-regions preferably have a width in the range of 0.5 mm to 5 mm.

[0047] In a preferred embodiment, the winding is a cylindrical winding. In a further embodiment, the winding may alternatively be a prismatic flat winding. As is well known, the structure of a prismatic flat winding is similar to that of a cylindrical winding. However, for the production of a flat winding, the electrode-separator composite is wound in a flat manner, not in a spiral manner around an axis, and the composite processed to give the flat winding includes flat, non-curved portions that rest on top of each other in a stack manner in the flat winding.

[0048] In a second particularly preferred variant of the cell of the invention, it has at least one of the additional features (a) to (e) immediately below: (a) the electrode-separator composite is part of a stack in which at least two electrode-separator composites are stacked on top of each other, together with at least one further identical electrode-separator composite; (b) at least two electrode-separator assemblies and their anodes, cathodes, and separators, and their anode current collectors and cathode current collectors, each having at least one longitudinal edge; (c) the anode current collectors each have a clear area along their longitudinal edge or one of their longitudinal edges, in particular in the form of a strip-shaped border area, (d) the cathode current collectors each have a clear area along their longitudinal edge or one of their longitudinal edges, in particular in the form of a strip-shaped edge area, (e) the anodes and cathodes of at least two electrode-separator composites are arranged offset from one another in the stack, and a clear area of ​​the anode current collector overlapping on one side of the stack; A clear area of ​​the cathode current collector overlaps on the further side of the stack.

[0049] Preferably, all of the immediately above features (a)-(e) are implemented simultaneously in combination with each other.

[0050] In this configuration in the form of a stack, the current collector preferably also has two flat sides, each side laminated with a layer of the respective electrode material. More preferably, both the edge region on the surface of the anode current collector and the edge region on the surface of the cathode current collector are divided by respective longitudinal edges, along which these edge regions extend into two subregions, each in the form of a strip, all of which are coated with the support material. More preferably, each subregion is coated with a strip of the support material. The current collector in this case is not laminated on both sides with the respective electrode material, but is coated on both sides with the support material. Preferably, the longitudinal edges are not coated with the support material.

[0051] The stack preferably has a maximum height in the range of 5 mm to 20 mm.

[0052] The anode and cathode current collectors, like the electrodes, are preferably rectangular in shape, and more preferably have lengths ranging from 100 mm to 300 mm, widths ranging from 50 mm to 150 mm, and thicknesses ranging from 50 μm to 250 μm.

[0053] The strip-shaped border regions and strip-shaped sub-regions preferably have a width in the range of 0.5 mm to 5 mm.

[0054] The cells of the present invention have at least one of the following additional features (a)-(d): (a) the coating of at least one clear area with a support material has a thickness in the range of 0.015 to 1.0 mm, preferably 0.05 to 0.2 mm; (b) at least one layer of cathode electrode material on the anode current collector has a thickness in the range of 0.03 to 1.0 mm, preferably 0.1 to 0.2 mm; (c) at least one layer of anode electrode material on the cathode current collector has a thickness in the range of 0.03 to 1.0 mm, preferably 0.1 to 0.2 mm; (d) The thickness of the support material coating on the anode current collector or the cathode current collector is 1% to 100% of the thickness of the layer of electrode material present thereon.

[0055] Preferably, all of the immediately above features (a)-(d) are implemented simultaneously in combination with each other.

[0056] In one development, the thickness of the coating of the support material on the anode current collector or the cathode current collector is between 5% and 50%, more preferably between 2% and 25%, of the thickness of the layer of electrode material present thereon.

[0057] The cells of the present invention more preferably have at least one of the additional features (a) to (c) immediately below: (a) the anode current collector and the cathode current collector are designed as claimed in claims 3 and 4, i.e. have the two flat sides and a clear area covered with a support material and divided into two subareas, (b) the cell includes a first electrical conductor welded onto the edge of the anode current collector; (c) The cell includes a second electrical conductor welded onto the edge of the cathode current collector.

[0058] Preferably, all of the immediately above features (a)-(d) are implemented simultaneously in combination with each other.

[0059] The electrical conductors can be welded in particular by laser welding or by TIG welding (tungsten-inert gas welding).

[0060] In preferred embodiments, the cells of the present invention further have at least one of the following characteristics (a) to (c): (a) The cell is designed as claimed in claim 6, i.e., has an electrode-separator composite in the form of a roll having two end faces, and an anode current collector in the form of a strip and a cathode current collector in the form of a strip, each having two longitudinal edges; (b) a first electrical conductor in strip form welded onto a longitudinal edge of the anode current collector along which the clear area of ​​the anode current collector extends; (c) A second electrical conductor is welded in strip form onto the longitudinal edge of the cathode current collector along which the clear area of ​​the cathode current collector extends.

[0061] Preferably, all of the immediately above features (a)-(c) are implemented simultaneously in combination with one another.

[0062] In a development of the preferred embodiment according to features (a) to (c) immediately above, the cell of the invention further comprises at least one of features (a) to (d) immediately below: (a) the first electrical conductor is a metal contact plate; (b) the second electrical conductor is a metal contact plate; (c) a first metal contact plate lying flat against an end surface of the winding and projecting from the end surface a longitudinal edge to which the contact plate is welded; (d) A second metal contact plate lies flat against the end face of the winding, projecting from the end face a longitudinal edge to which the contact plate is welded.

[0063] Preferably, all of the immediately above features (a)-(d) are implemented simultaneously in combination with each other.

[0064] In this development of the inventive cell, the excess current collectors resulting from the offset arrangement are utilized by contacting them over a large area with contact plates. The contact plates allow electrical contact of the current collectors, and thus the corresponding electrodes, over their entire length. This is because the flats on the end faces of the windings provide a linear contact area. If the electrode-separator composite is in the form of a spiral winding in this development, then the longitudinal edges of the anode and cathode current collectors, for example, protruding from the end faces of the windings, also have a spiral geometry. The situation in this case is similar to the linear contact areas where contact plates are welded to the longitudinal edges.

[0065] Preferably, the contact plates are joined by welding along their longitudinal edges along the linear contact area, as described in WO2017 / 215900A1, such a configuration is excellent for handling high current generation.

[0066] The contact plates can then be connected to the poles of the cell of the present invention, for example the anode and cathode of the housing.

[0067] The contact plate can be connected to the longitudinal edge along the linear contact area by at least one weld seam or by multiple weld points. More preferably, the longitudinal edges include one or more sections each connected to the contact plate continuously over their entire length by a weld seam. The longitudinal edges are optionally welded to the contact plate continuously over their entire length.

[0068] Welding a contact plate to the longitudinal edge can cause the first-mentioned problem, i.e., unintended compression or melting of the edge region of the current collector. These problems are solved by the support material. The support material mechanically supports the edge of the current collector and prevents edge melting, especially when the current collector is coated on both sides with the support material. Furthermore, the support material also prevents short circuits resulting from melting of the first-mentioned separator of the electrode-separator composite. The support material electrically insulates the clear area covered by it. Thus, it is electrically insulating in preferred embodiments.

[0069] The contact plates are preferably metal plates having a thickness in the range of 200 μm to 1000 μm, preferably 400 μm to 500 μm. They are preferably made of aluminum, aluminum alloy, titanium, titanium alloy, nickel, nickel alloy, stainless steel or nickel-plated steel. They are preferably made of the same material as the current collectors to which they are welded.

[0070] The contact plates preferably each have at least one groove and / or at least one perforation. The groove and / or perforation ensure that the contact plates do not warp during welding operations. Furthermore, the contact plates do not impede the penetration of electrolyte into the wound or stacked electrode-separator composite.

[0071] In a preferred embodiment, the contact plates are in the form of disks, in particular circular or at least approximately circular disks, in which case they have an outer circular or at least approximately circular disk edge. An approximately circular disk is understood here to mean in particular a disk having the shape of a circle from which at least one circular section has been removed, preferably two or four circular sections have been removed.

[0072] In a further preferred embodiment, the contact plate may also have the shape of a polygon, preferably a regular polygon, in particular a regular polygon having 4 to 10 vertices and sides.

[0073] In particular, in embodiments such as lithium-ion cells, the cells of the present invention are preferably configured as cylindrically round cells. In that case, it includes a cylindrical housing containing the wound electrode-separator composite contained by the cell. Cylindrical round cells have a height greater than their diameter. They are particularly suitable for automotive applications, electric motorcycles, or other applications with high energy demands.

[0074] The clear areas or subareas can be wholly or partly covered with support material. In contrast, at least one edge separating the flat sides and thus also the two subareas from each other is preferably not covered with support material.

[0075] Preferably, the height of the lithium-ion cells in the form of round cells is in the range of 15 mm to 150 mm. The diameter of the cylindrical round cells is preferably in the range of 10 mm to 50 mm. Within these ranges, for example, shape ranges of 18 x 65 (diameter x height (mm)) or 21 x 70 (diameter x height (mm)) are particularly preferred. Cylindrical round cells with these shape ranges are particularly suitable for powering the electric drive of automobiles.

[0076] The nominal capacity of the lithium-ion cells of the present invention in the form of cylindrical round cells is preferably up to 6000 mAh. In the 21x70 format range, the cells preferably have a nominal capacity in the range of 2000 mAh to 5000 mAh, more preferably 3000 to 4500 mAh, in one embodiment such as a lithium-ion cell.

[0077] In some embodiments, the cell of the present invention can be a button cell, particularly a lithium-ion button cell, having a metal housing composed of two housing parts insulated from each other by an electrically insulating seal, as shown, for example, in FIG. 1 of DE 10 2009 060 800 A1. In this case, a contact plate can be connected, for example, to the anodized half of the housing. The button cell is cylindrical in shape and has a height smaller than its diameter. The height is preferably in the range of 4 mm to 15 mm. Furthermore, the button cell preferably has a diameter in the range of 5 mm to 25 mm. Button cells are suitable for supplying electrical energy to small electronic devices such as watches, hearing aids, and wireless headphones.

[0078] The nominal capacity of the lithium-ion cells of the present invention in the form of button cells is generally up to 1500 mAh, preferably in the range of 100 mAh to 1000 mAh, more preferably in the range of 100 to 800 mAh.

[0079] In the European Union, manufacturing data for nominal capacity figures for secondary batteries are strictly restricted. For example, the nominal capacity figures for secondary nickel-cadmium batteries must be based on measurements according to standards IEC / EN 61951-1 and IEC / EN 60622, the nominal capacity figures for secondary nickel-metal hydroxide batteries measured according to standard IEC / EN 61951-2, the nominal capacity figures for secondary lithium batteries measured according to standard IEC / EN 61960, and the nominal capacity figures for secondary lead-acid batteries measured according to standard IEC / EN 61056-1. Any nominal capacity figures in this application should preferably be based on these standards as well.

[0080] The cell of the present invention can alternatively be part of a battery together with at least one further identical cell, in which case it is preferably connected in parallel or series to at least one further identical cell, and further the two cells preferably have a common housing and optionally a common electrolyte.

[0081] The method of the invention for the manufacture of the aforementioned electrochemical cells always comprises the following steps: (a) providing an anode comprising an anode current collector made of at least one metal and having a surface coated with at least one layer of cathode active electrode material; (b) providing a cathode comprising a cathode current collector made of at least one metal and having a surface coated with at least one layer of anode active electrode material; (c) Using the prepared anode and the prepared cathode, an electrode-separator composite is fabricated, which includes an anode, at least one separator, and a cathode.

[0082] According to the present invention, the preparation of the electrode-separator composite is carried out before or after the following step (d): (d) covering a clear area on the surface of the anode current collector that has not been coated with a cathode active electrode material and / or a clear area on the surface of the cathode current collector that has not been coated with a cathode active electrode material with a support material, the support material having a thermal stability greater than the thermal stability of the coated surface.

[0083] The materials and cell components used in said method have already been described in the description of the cell of the present invention, and reference is made thereto. In a preferred embodiment, the method has one of the following additional features: (a) a support material is deposited onto the clear region from the vapor phase; (b) the support material is applied to the clear area as part of a suspension or paste; (c) The support material is obtained from a sol-gel process.

[0084] The optimum procedure for coating a current collector with a support material depends on the type of support material. Deposition from the gas phase can be carried out, for example, by CVD or PVD methods (CVD = chemical vapor deposition, PVD = physical vapor deposition) or by modifications of these methods (e.g. atomic layer deposition, ALD). Whereas in PVD the materials to be deposited are often already in the gas phase in vapor form (they are converted into the gas phase by physical methods), in CVD the chemical compounds of the elements to be deposited (called precursors) are evaporated. These are decomposed on the surface of the substrate to give the desired foil material. In PVD, coatings can be formed by evaporation, sputtering, ion plating, and modifications of these methods.

[0085] Aluminum oxide coatings can be produced, for example, starting from organometallic aluminum compounds such as trimethylaluminum as precursors. It is also possible to produce the aforementioned titanium carbonitride (TCN) coatings, in particular by CVD methods. TiN and Ti-AlN coatings can be produced by PVD methods. Such methods are known from the literature.

[0086] The suspension or paste can be applied by common coating methods such as spraying, dip coating, printing and extrusion.

[0087] Oxide coatings, such as aluminum oxide coatings, can also be produced by sol-gel processes known from the literature. Aluminum oxide can be produced starting from aluminum alkyls, such as aluminum trisecbutoxide or aluminum triisopropoxide.

[0088] In principle, it is also possible to apply a support material to the current collector before the current collector is laminated with the electrode material. In this case, it is appropriate to mask the areas of the current collector that will be laminated with the active electrode material in a subsequent step. However, preferably, the support material is applied to a current collector that has already been laminated with the active electrode material. In this case, with appropriate masking, it is possible to cover only the aforementioned clear areas. However, for processing reasons, it is preferred to cover the entire electrode, including the layer of active electrode material, with the support material, and not just the clear areas. In this case, there is no need for masking.

[0089] In some preferred embodiments, the support material is applied to the clear area along with a first wide strip of each electrode material, but does not completely cover the clear area. Instead, it is applied in the form of a second strip or line along a longitudinal edge of the anode current collector and / or cathode current collector, leaving a third strip or line of each clear area along and parallel to this longitudinal edge uncovered. More preferably, the second strip or line separates the first and second strips or lines of electrode material. [Brief explanation of the drawings]

[0090] [Figure 1] FIG. 1 shows a schematic diagram of an embodiment of an electrode-separator composite from above at an angle. [Figure 2] FIG. 2 shows the contact plate. [Figure 3] FIG. 3 shows the placement of the contact plate on the end face. [Figure 4] FIG. 4 shows the result of the winding at an angle from above. [Figure 5] FIG. 5 shows a schematic cross-sectional view of an embodiment of an electrode-separator composite. [Figure 6] FIG. 6 shows the winding configuration shown in FIGS. [Figure 7] FIG. 7 shows the result of the winding in cross section. [Figure 8] FIG. 8 is a top view of the anode shown in cross section in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0091] Further features of the present invention and advantages resulting therefrom are apparent from the drawings and from the following description of the drawings. The embodiments described below serve only for a better understanding and explanation of the present invention and should not be construed as limiting in any way. 1 and 5 show, in a schematic perspective top view and in cross section, one embodiment of an electrode-separator composite 101 in the form of a spiral winding that can be fabricated to provide a cell 100 of the present invention. The winding has two end faces 103 and 109, only one of which, end face 103, is visible in FIG. 1. The electrode-separator composite 101 includes an anode 115 in the form of a strip, and a cathode 118 in the form of a strip, which are separated from each other by separators 116 and 117, also in the form of strips.

[0092] The two end faces 103 and 109 are formed by the longitudinal edges of strip-shaped separators 116 and 117. Within the electrode-separator composite 101, the electrodes 115 and 118 are positioned offset from one another, with the longitudinal edge of the anode 115 protruding from one of the end faces to form overhang 110 and the longitudinal edge of the cathode 118 protruding from the opposite end face to form overhang 102.

[0093] FIG. 6 serves to illustrate the winding configuration shown in FIGS. 1 and 5. Shown here are the anode 115 and the capacitor S1A and 1B are cross-sections of the precursors for electrodes 115 and 118, and for each of the two electrodes 115 and 118. The precursors differ from electrodes 115 and 118 only in that each of the latter has a coating of support material 119. Like electrodes 115 and 118, they include an anode current collector 115a and a cathode current collector 118a. Anode current collector 115a is copper foil. Cathode current collector 118a is aluminum foil. The foils each have two flat sides 115d, 115e and 118d, 118e, which are separated from each other by longitudinal edges 115f, 115g and 118f, 118g, and are laminated on either side with layers 115b, 118b of active electrode material, respectively.

[0094] The surface of the anode current collector 115a and the surface of the cathode current collector 118a each include a strip-shaped clear region 115c, 118c that is not covered with the respective active electrode material. Each of these clear regions includes two strip-shaped subregions on the two flat sides 115d, 115e of the anode current collector 115a and the two flat sides 118d, 118e of the cathode current collector 118a. These subregions are each coated with a layer of aluminum oxide as support material 119 in the electrode of winding 101. The longitudinal edges 118f, 115g do not have support material 119 themselves.

[0095] The clear areas 115c and 118c are made more stable against mechanical and thermal stress by the support material 119 applied to both sides, which also electrically insulates the areas 115c and 118c.

[0096] A top view of the anode 115 shown in cross section in FIG. 6 is shown in FIG.

[0097] 1 and 5, a longitudinal edge 115g of the anode current collector 115a protrudes from the end face 109 along with a clear area 115c covered with a support material 119. A longitudinal edge 118f of the cathode current collector 118a protrudes from the end face 103 along with a clear area 118c. The protruding longitudinal edges 115g and 118f similarly have a helical geometry as a result of the helical winding of the electrode-separator composite 101.

[0098] To manufacture the cell 100 of the present invention, two contact plates 104 are laid flat on the end faces 103 and 109 of the windings. Figure 3 shows the placement of the contact plate 104 on the end face 103. This results in a linear contact area between the contact plates and the longitudinal edges 115g and 118f protruding from the end faces 103 and 109. The contact plates are joined by welding to the longitudinal edges 115g and 118f along the linear contact area. This allows the current collectors 115a and 118a to be in electrical contact over their entire length.

[0099] The contact plates 104 are shown in FIG. 2. They take the form of generally circular plates. They are only generally circular because the disc edge 113 deviates from a perfect circular geometry in four places 113a-113d, each of which has a flat circular area removed. The contact plate 104 has grooves 105a, 105b, 105c, and 105d. The four grooves are arranged extending radially from the outer disc edge 113 toward the center of the contact plate. At its center, the contact plate 104 has a passage 114 in the form of a circular hole. To the right and left of the central opening 114 are two further passages 120 and 121. These can serve as positioning aids during installation of the contact plate 104.

[0100] The result of the welding is shown in FIG. 4 (top view oblique from above) and FIG. 7 (cross-sectional view). The contact plate 104 and the longitudinal edge 118f are connected by a weld seam 122. The latter here has the same helical profile as the longitudinal edge 118f. The weld seam 122 exactly follows the helical profile of the longitudinal edge 118f. However, due to the grooves 105a-105d, the longitudinal edge 118f cannot be welded continuously to the contact plate 104 over its entire length. Instead, the longitudinal edge 118f, interrupted by the grooves 105a-105d, has multiple sections, each continuously connected to the contact plate 104 over its entire length by the weld seam 122 along the contact area.

Claims

1. An electrochemical cell (100), comprising: (a) an electrochemical cell (100) comprising an electrode-separator composite (101), the electrode-separator composite (101) having an anode (115), at least one separator (116, 117), and a cathode (118); (b) the anode (115) comprises an anode current collector (115a), the anode current collector (115a) being made of at least one metal and having a surface coated with at least one layer (115b) of a cathode active electrode material; (c) the cathode (118) comprises a cathode current collector (118a), the cathode current collector (118a) being made of at least one metal and having a surface laminated with at least one layer (118b) of anode active electrode material; (d) the surface of the anode current collector (115a) and / or the surface of the cathode current collector (118a) comprises at least one clear area (115c; 118c) that is not covered with the respective active electrode material; (e) In at least one clear region (115c; 118c), the surface of the anode current collector (115a) and / or the surface of the cathode current collector (118a) are coated with a support material (119), and the thermal stability of the support material (119) is greater than the thermal stability of the coated surface; an anode current collector (115a) having two flat sides (115d, 115e) separated from each other by at least one longitudinal edge (115f, 115g); an anode current collector (115a) having at least one layer (115b) of cathode active electrode material laminated on two flat sides (115d, 115e); a clear area (115c) is provided on each of the two flat sides (115d, 115e) of the anode current collector (115a); These clear areas (115c) are covered with a support material (119), The electrochemical cell (100) includes a first electrical conductor (104) welded onto a longitudinal edge (115g) of an anode current collector (115a); a cathode current collector (118a) having two flat sides (118d, 118e) separated from each other by at least one longitudinal edge (118f, 118g); a cathode current collector (118a) having at least one layer (118b) of anode active electrode material laminated on two flat sides (118d, 118e); a clear area (118c) is provided on each of the two flat sides (118d, 118e) of the cathode current collector (118a); These clear areas (118c) are covered with a support material (119), The electrochemical cell (100) includes a second electrical conductor (104) welded onto a longitudinal edge (118f) of the cathode current collector (118a); a support material (119) is applied to a clear area of ​​the current collector welded to the first electrical conductor (104) near the longitudinal edge welded to the first electrical conductor (104), but not along the longitudinal edge opposite the welded longitudinal edge; 1. An electrochemical cell comprising: a current collector welded to a second electrical conductor; a support material (119) applied to a clear area along a longitudinal edge of the current collector welded to the second electrical conductor; and a support material (119) not applied to a portion of the current collector along a longitudinal edge opposite the welded longitudinal edge.

2. Electrochemical cell according to claim 1, characterized in that: (a) at least one metal constituting the surface of the anode current collector (115a) comprises at least one metal selected from the group consisting of copper, copper alloy, titanium, titanium alloy, nickel, nickel alloy, and stainless steel; (b) the anode current collector (115a) is made of at least one metal; (c) the anode current collector (115a) is a metal foil, a metal sponge, a fiber cloth, or an expanded metal; (d) the at least one metal constituting the surface of the cathode current collector (118a) comprises at least one metal selected from the group consisting of aluminum, aluminum alloy, titanium, titanium alloy, and stainless steel; (e) the cathode current collector (118a) is made of at least one metal; (f) The cathode current collector (118a) is a metal foil, a metal sponge, a fiber cloth, or an expanded metal.

3. 3. An electrochemical cell according to claim 1 or 2, characterized in that: (a) the support material (119) is a non-metallic material; (b) the non-metallic material is a ceramic material, a glass-ceramic material, or a glass; (c) The ceramic material is aluminum oxide (Al2O3) or titanium oxide (TiO2).

4. Electrochemical cell according to any one of claims 1 to 3, characterized in that: (a) the electrode-separator composite (101) is in the form of a winding having two end faces (103, 109); (b) the electrode-separator composite (101) and at least one separator (116, 117) contained therein, the electrodes (115, 118) and the anode current collector (115a) and cathode current collector (118a) contained therein are in the form of strips, each having two longitudinal edges; (c) the two end faces (103, 109) of the electrode-separator composite are formed by the longitudinal edges of at least one separator (116, 117); (d) the surface of both the anode current collector (115a) and the cathode current collector (118a) includes clear areas (115c, 118c) that are not covered with active electrode material; (e) the clear area (115c) on the surface of the anode current collector (115a) is a strip-shaped edge area along one of its two longitudinal edges (115g); (f) the clear area (118c) on the surface of the cathode current collector (118a) is a strip-shaped edge area along one of its two longitudinal edges (118f); (g) an anode (115) in strip form and a cathode (118) in strip form are arranged offset from one another within the electrode-separator composite (100); a longitudinal edge (115g) of the anode current collector (115a) protrudes from one of the two end faces (109) together with a clear area (115c) of the anode current collector (115a); A longitudinal edge (118f) of the cathode current collector (118a) protrudes from the other of the two end faces (103) along with a clear area (118c) of the cathode current collector (118a).

5. Electrochemical cell according to any one of claims 1 to 4, characterized in that: (a) the electrode-separator composite is part of a stack in which at least two electrode-separator composites are stacked on top of each other, together with at least one further identical electrode-separator composite; (b) at least two electrode-separator assemblies and their anodes, cathodes, and separators, and their anode current collectors and cathode current collectors, each having at least one longitudinal edge; (c) the anode current collectors have a clear area along one of their longitudinal edges; (d) the cathode current collectors have a clear area along one of their longitudinal edges; (e) the anodes and cathodes of at least two electrode-separator composites are positioned offset from one another within the stack; a clear area of ​​the anode current collector overlapping on one side of the stack; A clear area of ​​the cathode current collector overlaps on the further side of the stack.

6. Electrochemical cell according to any one of claims 1 to 5, characterized in that: (a) the coating of at least one clear area (115c, 118c) with a support material (119) has a thickness in the range of 0.015 to 1.0 mm; (b) at least one layer (115b) of cathode electrode material on the anode current collector (115a) has a thickness in the range of 0.03 to 1.0 mm; (c) at least one layer (118b) of anode electrode material on the cathode current collector (118a) has a thickness in the range of 0.03 to 1.0 mm; (d) The thickness of the coating of the support material (119) on the anode current collector or the cathode current collector is 50% to 100% of the thickness of the layer of electrode material present thereon.

7. Electrochemical cell according to claim 1, characterized in that: (a) an electrochemical cell (100) designed as claimed in claim 6; (b) a first electrical conductor (104) in strip form is welded onto the longitudinal edge (115g) of the anode current collector (115a) along which the clear area (115c) of the anode current collector (115a) extends; (c) A second electrical conductor (104) is welded in strip form onto the longitudinal edge (118f) of the cathode current collector (118a) along which the clear area (118c) of the cathode current collector (118a) extends.

8. 8. An electrochemical cell according to claim 7, having the following additional features: (a) the first electrical conductor (104) is a metal contact plate; (b) the second electrical conductor (104) is a metal contact plate; (c) a first metal contact plate (104) lying flat against the end face (109) of the winding and projecting from that end face (109) a longitudinal edge (115g) to which the contact plate is welded; (d) A second metal contact plate (104) lies flat against the end face (103) of the winding, from which end face (103) projects a longitudinal edge (118f) to which the contact plate is welded.

9. Electrochemical cell according to any one of claims 1 to 8, characterized in that: (a) The electrochemical cell is part of a battery together with at least one further identical cell.

10. A method for manufacturing an electrochemical cell (100) according to any one of claims 1 to 8, said method comprising: (a) providing an anode (115) comprising an anode current collector (115a) made of at least one metal and having a surface coated with at least one layer (115b) of a cathode active electrode material; (b) providing a cathode (118) comprising a cathode current collector (118a) made of at least one metal and having a surface coated with at least one layer (118b) of anode active electrode material; (c) using the prepared anode (115) and the prepared cathode (118) to manufacture an electrode-separator composite (101) comprising an anode, at least one separator, and a cathode, wherein the manufacture of the electrode-separator composite comprises the following steps: (d) or (e) (d) covering the clear area (115c) on the surface of the anode current collector (115a) that has not been laminated with the cathode active electrode material and / or the clear area (118c) on the surface of the cathode current collector (118a) that has not been laminated with the cathode active electrode material with a support material (119), wherein the support material (119) has a thermal stability greater than the thermal stability of the surface on which it is coated.

11. 11. The method of claim 10, having the following additional features: (a) a support material (119) is deposited from the gas phase onto the clear regions (115c, 118c), or (b) A support material (119) is applied to the clear areas (115c, 118c) as part of a suspension or paste.

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