Electrochemical cell having contact lug

Abstract

To provide an electrochemical cell containing a contact lug to be improved.SOLUTION: A cell 400 contains a circular-shaped housing surrounding an internal space. A contact lug 40 is fixed to the first or second end surface of the circular-shaped housing. The contact lug contains a first contact connection region to be adhered to an end surface 2, and then, the contact lug is fixed to the end surface (e). The contact lug contains a first contact connection region 44 to be mounted to the end surface, and then, the contact lug is fixed to the end surface. The contact lug contains a second contact connection region 45 that is mounted to an end surface for contact connection of the external electric conductor and electrochemical cell. The contact lug between the first and second contact connection regions contains an attenuation region 46 that can realize a free vibration. The first contact connection region and the attenuation region are extended in a surface in parallel to a flat surface of the end surface of the housing to which the contact lug is fixed, and the second contact connection region is extended to the flat surface so as to form an angle.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to an electrochemical cell having a cylindrical housing and at least one contact lug.

Background Art

[0002] The function of an electrochemical cell is energy storage. They include a positive electrode and a negative electrode, which are separated from each other by a separator. In this type of energy storage cell, electrochemical and energy release reactions occur, which consist of two electrically interconnected but spatially separated partial reactions. The partial reaction that occurs at a relatively low redox potential proceeds at the negative electrode. The other partial reaction occurs at a relatively high redox potential at the positive electrode. During discharge, electrons are released at the negative electrode by an oxidation process, which results in an electron flow that flows to the positive electrode through an external load, where a corresponding amount of electrons is absorbed. Thus, a reduction process occurs at the positive electrode. At the same time, for the purpose of charge equalization, an ion flow corresponding to the electrode reaction exists within the cell. This ion flow passes through the separator and is delivered by an ion-conductive electrolyte.

[0003] In a secondary (rechargeable) electrochemical energy storage cell, this discharge reaction is reversible, and thus it is possible for the conversion of chemical energy to electrical energy to be reversed in relation to discharge.

[0004] Small cells such as button cells have particularly many application fields. Button cells, by definition, are cells having a height smaller than their diameter. They generally include a cylindrical housing, which is composed of two metal housing parts, the parts of which are electrically insulated from each other, one of which is connected as the anode and the other is connected as the cathode. The housing generally includes a first and a second end face, which each have a circular or elliptical peripheral shape and are interconnected by an annular shell.

[0005] In an electronic device (e.g., a circuit board), contact lugs are frequently required to fix a cell such as a button cell. The contact lugs first function as mechanical fixing means, but secondarily also function as electrical conductors. Generally, one contact lug is connected to the anode and a second contact lug is connected to the cathode. The connection to the housing of the button cell is effected in particular by soldering or welding.

[0006] For technical manufacturing reasons, the contact lugs generally conform to the end face of the button cell.

[0007] By bending one of the contact lugs by 90°, this contact lug can be brought to the side of the opposite end face. If the contact lugs are in the same plane, the fixing to the circuit board is particularly simple.

[0008] Cells with contact lugs are known, for example, from EP3667761A1 and US2011 / 001618A1.

[0009] In recent years, rechargeable button cells have been developed based on lithium-ion technology (see, for example, WO2010 / 089152A1). This type of button cell requires high safety means because in case of damage, their high energy density and easily flammable components can pose a major danger to consumers.

[0010] Known safety means for button cells include the formation of a fracture surface at one of their end faces. If excessive pressure exceeding the pressure threshold value occurs inside the cell, the housing of the button cell can open in a controlled manner in the region of the fracture surface and release the excessive pressure.

[0011] However, this type of fracture surface is easily blocked when soldering the contact lugs to the end face including the fracture surface.

[0012] In cells with contact lugs, further problems occur where the contact lugs can become detached from their respective end faces to which they are fixed in response to the shocks, oscillations or vibrations to which they are exposed. SUMMARY OF THE INVENTION

[0013] The present invention addresses the object of providing an electrochemical cell comprising an improved contact lug with respect to the above problems. A cell with an improved contact lug exhibits high resistance to the above mechanical loads and / or is characterized by improved safety, especially in combination with a pressure relief valve such as the above-mentioned rupture cross-section.

[0014] This object is met by an electrochemical cell having the features of claim 1. Advantageous configurations of this cylindrical cell are the subject of the dependent claims. Specifically, according to the present application, the following configurations [1] to

[14] are provided. [1] An electrochemical cell (200; 300; 400) having the following features (a) to (d) and further having the following features (e) to (h): (a) The cell comprises a cylindrical housing surrounding an internal space, the cylindrical housing having a first end face (2) and a second end face, the end faces being interconnected by an annular shell; (b) A positive electrode and a negative electrode are arranged inside the housing; (c) The negative electrode is electrically connected to the first end face (2) directly or by a separate electrical conductor to form a cathode, and the positive electrode is electrically connected to the second end face directly or by a separate electrical conductor to form an anode: (d) A contact lug (20; 30; 40) is fixed to the first or second end face (2) of the housing; (e) The contact lug (20; 30; 40) comprises a first contact connection area (24; 34; 44) mounted on the end face, where the contact lug is fixed to the end face (2); (f) The contact lug (20; 30; 40) comprises a second contact connection area (25; 35; 45) mounted on the end face for electrical contact connection with an external electrical conductor; (g) The contact lug (20; 30; 40) between the first contact connection area (24; 34; 44) and the second contact connection area (25; 35; 45) includes a damping area (26; 36; 46) that can vibrate freely; (h) The first contact connection area (24; 34; 44) and the damping area (26; 36; 46) extend in a plane parallel to the plane of the end face (2) of the housing to which the contact lug is fixed, and the second contact connection area (25; 35; 45) extends at an angle to the said plane or the second contact connection area (25; 35; 45) and the damping area (26; 36; 46) are arranged in the same plane. [2] The electrochemical cell according to [1], having the following additional feature (a): (a) The damping area (26; 36; 46) is not directly connected to the end face (2) to which the contact lug is fixed. [3] The electrochemical cell according to [1] or [2], having at least one of the following additional features (a) to (c): (a) The damping area (26; 36; 46) is configured in a strip shape; (b) The damping area includes at least one strip-shaped area with an essentially constant width; (c) The contact lug includes a transition area from the first contact connection area (24; 34; 44) to the damping area (26; 36; 46), where the width of the contact lug decreases such that the cross-section of the contact lug is reduced by at least 30%, preferably at least 50%. [4] The electrochemical cell according to any one of [1] to [3], having the following additional feature (a): (a) The damping area (36; 46) takes a curved profile, particularly an annular profile. [5] The electrochemical cell according to any one of [1] to [4], particularly the electrochemical cell according to [4], having at least one of the following additional features (a) to (c): (a) The cell includes a safety valve (50); (b) The cell (400) includes a safety valve in the form of a fracture surface; (c) The damping area (36; 46) takes a curved profile around the safety valve. [6] The electrochemical cell according to any one of [1] to [5], having the following additional feature (a): (a) The contact lug (20; 30; 40) extends beyond the edge of the end face (2) to which it is fixed. [7] The electrochemical cell according to any one of [1] to [6], having the following additional features (a) and (b): (a) The cell includes, as a first contact lug, a contact lug (20; 30; 40) fixed to the first or second end face (2) of the housing; (b) The cell includes a second contact lug on the end face of the housing arranged opposite to the end face (2) to which the first contact lug (20; 30; 40) is fixed. [8] The electrochemical cell according to [7], having the following additional feature (a): (a) The second contact lug (6) extends over an angled contact lug region (8) in the plane of the opposite end face (2). [9] The electrochemical cell according to any one of [1] to [8], having the following additional feature (a): (a) The cell is configured to be fixed to a circuit board.

[10] The electrochemical cell according to any one of [1] to [9], having at least one of the following additional features (a) and (b): (a) The contact lug(s) (20; 30; 40) is / are sheet metal parts; (b) The contact lug(s) (20; 30; 40) is / are stamped parts.

[11] The electrochemical cell according to any one of [1] to

[10] , having the following additional feature (a): (a) The contact lug(s) (20; 30; 40) has / have a thickness in the range of 0.05 mm to 2.5 mm, preferably 0.25 mm to 2.5 mm.

[12] The electrochemical cell according to any one of [1] to

[11] , having the following additional feature (a) or (b): (a) The contact lug(s) (20; 30; 40) is / are composed of steel, particularly special steel; (b) The contact lug(s) (10; 30; 40) is / are made of nickel or nickel-plated metal or nickel alloy.

[13] An electrochemical cell according to any one of [1] to

[12] , having the following additional features: (a) The cell is a lithium-ion cell.

[14] An electrochemical cell according to any one of [1] to

[13] , having at least one of the following additional features (a) to (c): (a) The cell is a button cell; (b) The cell has a diameter in the range of 5 mm to 25 mm; (c) The cell has a height in the range of 1.5 mm to 15 mm, preferably 3 mm to 15 mm.

[0015] The electrochemical cell according to the present invention is first characterized by the following features: (a) The cell includes a cylindrical housing surrounding an internal space, the cylindrical housing having a first end face and a second end face, and those end faces being interconnected by an annular shell; (b) A positive electrode and a negative electrode are disposed inside the housing; (c) The negative electrode is electrically connected to the first end face directly or by a separate electrical conductor to form a cathode, and the positive electrode is electrically connected to the second end face directly or by a separate electrical conductor to form an anode: (d) A contact lug is fixed to the first or second end face of the housing.

[0016] According to the present invention, the electrochemical cell is further characterized by the following features with respect to the contact lug: (e) The contact lug includes a first contact connection area mounted on the end face, where the contact lug is fixed to the end face; (f) The contact lug includes a second contact connection area mounted on the end face for contact connection between an external electrical conductor and the electrochemical cell; (g) The contact lug between the first contact connection area and the second contact connection area includes a damping area capable of free vibration; (h) The first contact connection area and the attenuation area extend in a plane parallel to the plane of the end face of the housing to which the contact lug is fixed, and the second contact connection area preferably extends at an angle to the said plane.

[0017] By virtue of the configuration of the contact lug having a first contact connection area mounted on the end face for fixing the contact lug to the end face and a second contact connection area mounted on the end face for contact connection with an external electrical conductor, in particular with an intervening attenuation area, the cell according to the invention achieves a significant improvement with regard to the shock and vibration sensitivity of the electrochemical cell. In particular, by means of the attenuation area in the central region of the contact lug, the shock and vibration to which the contact lug is exposed can be buffered and attenuated, so that not all of the magnitude of the said shock or vibration is imparted to the contact connection area, in particular the first contact connection area, and as a result the contact connection area, in particular the first contact connection area, is substantially protected against vibration.

[0018] The fixing of the contact lug in the first contact connection area is generally carried out by welding. For example, laser welding, and in a particularly advantageous manner, resistance welding is used for this purpose. For this purpose, a plurality of weld points, for example two or four or six weld points, can be provided in the first contact connection area. In conventional electrochemical cells, as a result of the shock or vibration acting on the cell, one or more of these weld points can be damaged, and thus there can arise the problem that loosening of the contact lug from the end face, and even detachment, can potentially occur. In the electrochemical cell according to the invention, this problem is reduced, where the shock or vibration acting on the contact lug is alleviated and attenuated by the attenuation area arranged between the contact connection areas mounted on the end face.

[0019] The contact lug of the cell according to the present invention described above can replace the conventional contact lug. The conventional contact lug is composed only of a flat contact connection area (first contact connection area) where the contact lug is fixed to the end face of the cell, and a contact spike through which the electrochemical cell can be contact-connected to an external electrical conductor. This contact spike is generally formed directly on the flat contact connection area in the form of a narrow protrusion, and can be angled so that an external electrical conductor can be soldered or clamped to the contact spike, for example. An example of a contact lug having a non-angled contact spike is shown in FIG. 1 (reference number 106) of EP3667761A1.

[0020] By mitigating impacts or vibrations by means of the damping area, the connection between the second contact connection area and the external electrical conductor can also be protected. Thus, for example, the occurrence of fatigue or defects and / or cracks at the soldering or clamping points between the second contact connection area and the external electrical conductor can be prevented.

[0021] Optionally, the damping area of the contact lug according to the present invention can also deflect and / or attenuate electromagnetic waves that may have a damaging effect on the cell according to the present invention.

[0022] As described above, in a preferred embodiment, the second contact connection area extends at an angle with respect to the plane of the end face to which the contact lug is fixed. In other words, the second contact connection area is preferably angled with respect to the first contact connection area and the damping area. An angle of 90° is particularly preferred. In these preferred embodiments, the boundary between the second contact connection area and the damping area is preferably constituted by a curved area where the contact lug is bent upwards. In this case, the area of the contact lug that is not oriented parallel to the end face is the second contact connection area.

[0023] In each case, the first and second end faces of the housing of the cell according to the present invention preferably have a circular or elliptical peripheral shape and are interconnected by an annular shell.

[0024] In the manufacture of a cylindrical cell according to the present invention, a contact lug having a first contact connection area, a second contact connection area, and a damping area disposed therebetween is preferably first configured as a flat component, for example a stamped sheet metal part, and all of these areas are arranged in a single plane. In this form, the contact lug can be fixed to the end face of the cell in the first contact connection area. The bending or angling of the second contact connection area to facilitate connection of the external electrical conductor to the second contact connection area need not be carried out until a later stage.

[0025] Alternatively, the bending or angling can also be carried out before fixing the contact lug to the end face.

[0026] The end face to which the above-mentioned contact lug is fixed is preferably the end face of the cylindrical electrochemical cell constituting the cathode of the cell.

[0027] In a particularly preferred configuration of the cylindrical cell according to the present invention, the cell is characterized by the following additional features: (a) The damping area is not directly connected to the end face to which the contact lug is fixed.

[0028] According to feature (a) specified above, the damping area is only indirectly connected to the end face. Thus, the damping area constitutes to some extent the freely vibrating range of the first contact connection area, and this freely vibrating range forms a transition to the second contact connection area mounted at the end, through which the contact connection of the electrochemical cell to the external electrical conductor can be carried out.

[0029] In a particularly preferred embodiment, the damping area of the cylindrical cell is characterized by at least one of the following features (a) to (c): (a) The damping area is configured in a strip shape; (b) The damping area includes at least one strip-shaped area having an essentially constant width; (c) The contact lug includes a transition region from the first contact connection region to the attenuation region, where the width of the contact lug decreases such that the cross-section of the contact lug is reduced by at least 25%, preferably at least 50%.

[0030] Preferably, (a) and (b) of the above features, and particularly preferably (a) to (c) of the above features, are realized in combination with each other.

[0031] It is particularly preferred that the strip-shaped region having an essentially constant width, or the attenuation region, in particular the strip-shaped attenuation region, has a length that exceeds at least twice, particularly preferably at least four times, the maximum length of the second contact connection region.

[0032] It is further preferred that the strip-shaped region having an essentially constant width, or the attenuation region, in particular the strip-shaped attenuation region, exceeds at least 1.1 times, particularly preferably at least twice, and particularly three times the maximum length of the first contact connection region.

[0033] The presence of the transition portion from the first contact connection region to the attenuation region does not exclude, at least locally, including a further increase in the width of the contact lug, i.e., the cross-section, within the attenuation region.

[0034] The change in the width of the contact lug at the transition portion can be configured to increase gradually or continuously. With this configuration of the attenuation region, vibrations or impacts generated from the second contact connection region acting on the contact lug can be mitigated and attenuated in a particularly effective manner before they reach the first contact connection region.

[0035] In a particularly preferred configuration, the attenuation region is characterized by the following features: (a) The attenuation region has a curved profile, in particular an annular profile.

[0036] The curved profile of the damping region first gives the special advantage that a relatively long damping region can be achieved, where the limited surface area of the end face of the cylindrical cell can be utilized in an optimal way. The expansion of the damping region thus made possible allows impacts or vibrations to be more effectively cushioned. The damping region within the contact lug can be, to some extent, in the form of a track or strip and preferably can be curved. The curved profile can preferably follow an arc of a circle. For example, the damping region can take the form of an approximation of three-quarters of a circle.

[0037] The configuration of the damping region with a curved profile further gives additional special advantages. In particular, due to the curved profile, the contact lug can keep the central region empty so that the central region of the end face is available for other purposes.

[0038] In a particularly preferred configuration, the cell according to the invention is characterized by at least one of the features (a) to (c) specified below: (a) The cell includes a safety valve; (b) The cell includes a safety valve in the form of a breaking cross-section; (c) The damping region takes a curved profile around the safety valve.

[0039] Preferably, both of the above features (a) and (c), and particularly preferably, the above features (a) to (c) are realized in combination with each other.

[0040] Known safety means are provided for the cell, in particular for button cells, where a safety valve, in particular a safety valve in the form of a breaking cross-section, is included in one of the end faces. When an excessive pressure built up within the cell exceeds a specific pressure threshold, the safety valve (e.g., the breaking cross-section) that constitutes a predetermined breaking point can open so that the excessive pressure can be released.

[0041] In a particularly preferred embodiment of the invention, the above-mentioned central region of the end face in the empty state is used for safety purposes, in particular for the position of the safety valve. It is particularly advantageous for the safety valve, in particular the breaking cross-section, to be located in the region of the end face, in particular the central region, and the central region is kept in the empty state by the curved profile of the contact lug. Thus, it is achieved that the breaking cross-section, or the safety valve configured in an optionally different manner, is not obstructed by the contact lug.

[0042] The contact lug of the cylindrical cell according to the invention is preferably characterized by the following additional features specified below: (a) The contact lug extends beyond the edge of the end face to which it is fixed.

[0043] As described above, each of the first and second end faces of the cell according to the invention preferably has a circular or elliptical peripheral shape and is interconnected by an annular shell.

[0044] If the second contact connection area and the damping area are arranged in the same plane, the contact lug preferably projects beyond the edge of the end face to which it is fixed, preferably beyond the periphery of the shell. In this case, the part of the contact lug that does not engage with the end face constitutes the second contact connection area. The second contact connection area does not engage with the end face but is angled from it or projects beyond the edge of the end face to which it is fixed, so it is accessible in a particularly practicable way for contact connection and thus enables a particularly simple connection to an external electrical conductor. For example, in a manner known per se, the second contact connection area can be connected to an electrical conductor (e.g., a wire) by soldering or clamping, thus constituting contact with each pole of the cell according to the invention.

[0045] In a particularly preferred way, the cell according to the invention is characterized by the following additional features (a) and (b) specified below: (a) The cell includes, as a first contact lug, a contact lug fixed to the first or second end face of the housing; (b) The cell includes a second contact lug on the end face of the housing arranged opposite to the end face to which the first contact lug is fixed.

[0046] In addition to the first contact lug already described in detail, the cell can further include a further contact lug fixed to the opposite end face. As described above, the contact lug can, in a preferred embodiment, be guided to the side of the opposite end face by bending over 90°. Correspondingly, the cell according to the invention is preferably characterized by the additional feature (a) specified below: (a) The second contact lug extends over an angled contact lug region in the plane of the opposite end face.

[0047] Due to the angled contact lug region, the contact connections of both poles of the cylindrical cell can be carried out in a particularly feasible way from one side of the cell. Thus, this configuration of the cylindrical cell according to the invention enables, for example, in a particularly preferred configuration, a simple fixation of the cell to the circuit board.

[0048] The second contact lug can be configured, for example, like the contact lug specified by reference number 107 in FIG. 2 of the above-mentioned EP3667761A1.

[0049] In a conventional cylindrical cell, in particular the first contact lug is a relatively small component, which in principle consists only of a flat contact connection area where the contact lug is fixed to the end face of the cell and a second contact connection area in the form of a contact spike. The small size of this component can lead to difficulties in the cell manufacturing process. This is because this small component is difficult to handle during the fixation of the contact lug to the end face. Conversely, the contact lug having a damping region according to the invention gives the special advantage that the pick-up selection for the contact lug in the manufacturing process of the cylindrical cell, in particular in automated manufacturing, is significantly improved and as a result simplified. Therefore, the cell according to the invention is also particularly advantageous with respect to manufacturing and its manufacturing costs. Therefore, the cell according to the invention is particularly suitable for automated manufacturing.

[0050] In a particularly preferred embodiment, the contact lug(s) of the cylindrical cell according to the invention is / are characterized by at least one of the following additional features (a) and (b): (a) The contact lug(s) is / are a sheet metal part; (b) The contact lug(s) is / are a stamped part.

[0051] Sheet metal parts, especially those in the form of stamped parts, can be manufactured very simply and cost-effectively, and furthermore do not significantly increase the weight of the resulting cylindrical cell.

[0052] Preferably, the contact lug(s) is / are a very thin sheet material part. In a particularly preferred embodiment, the contact lug(s) of the cylindrical cell according to the invention can include the following additional features specified below with respect to the thickness of the contact lug: (a) The contact lug(s) has / have a thickness in the range of 0.05 mm to 2.5 mm, preferably 0.25 mm to 2.5 mm.

[0053] The thickness of the contact lug within the above range ensures sufficient safety of the contact lug. On the other hand, this thickness of the contact lug ensures sufficient vibration ability of the first contact lug in the damping area, so that the impact or vibration acting on the first contact lug as a result can be relaxed and damped in a particularly effective way.

[0054] Metal materials are particularly suitable as contact lug materials. In a particularly preferred embodiment, the cylindrical cell according to the invention can include the following additional features specified below with respect to the material used for the contact lug(s): (a) The contact lug(s) is / are composed of steel, especially special steel.

[0055] As the steel, for example, "CRCA steel" (CRCA = cold rolled closed annealed) can be used.

[0056] Alternatively, the contact lug(s) can also be composed of nickel or nickel-plated metal, or a nickel alloy.

[0057] In a particularly preferred configuration of the electrochemical cylindrical cell, the cylindrical cell is a lithium-ion cell. Lithium-ion cells are characterized by a particularly high energy density and can therefore be used in a particularly advantageous manner in various applications. In connection with lithium-ion cells, the configuration of the first contact lug according to the invention further provides an advantage in that the safety aspect of the lithium-ion cell is also considered in a specific way. In particular, the first contact lug according to the invention provides options for the configuration of the damping zone, especially in a curved shape, so that the rupture cross-section is not hindered.

[0058] In a particularly preferred configuration of the cylindrical cell according to the invention, the cell is characterized by at least one of the additional features specified below: (a) The cell is a button cell; (b) The cell has a diameter in the range of 5 mm to 25 mm; (c) The cell has a height in the range of 1.5 mm to 15 mm, preferably 3 mm to 15 mm.

[0059] Preferably, (a) and (b), or (a) and (c) of the above features, and particularly preferably (a), (b) and (c) of the above features, are realized in combination with each other.

[0060] The housing of the cell according to the invention is preferably formed from two metal housing parts, which are preferably configured in a cup shape. In addition to their respective preferred circular bases, they preferably include a hollow cylindrical shell. The outside of the base preferably constitutes the end face described above.

[0061] An annular plastic seal is preferably arranged between the two metal housing parts, which electrically insulates the housing parts from each other. The seal further ensures a fluid-tight closure of the cell.

[0062] The housing part can be composed of, for example, nickel-plated steel or a steel material. A combination of three metals, for example, an arrangement of nickel, steel (or special steel) and copper, is also conceivable. It is also conceivable that one housing part is composed of aluminum or an aluminum alloy and the other is composed of steel or a three-metal material.

[0063] The electrodes of the cell are preferably configured in strip form and are components of a composite winding body, which is arranged in the internal space of the housing. This preferably consists of at least two strip electrodes (positive and negative electrodes) wound spirally around a winding axis and at least one separator strip wound spirally around the winding axis. Preferably, the composite winding body is also configured as a cylinder and preferably also includes two corresponding circular end faces.

[0064] The end faces of the composite winding body are preferably formed by the longitudinal edges of at least one separator strip and are directed in the direction of the circular and mutually parallel housing base, so that the winding axis is directed vertically or essentially parallel to the housing base. The winding axis and the cylinder axis preferably coincide. An exemplary composite winding body of this type is described in particular in WO2010 / 089152A1.

[0065] Both the positive and negative electrodes preferably include a strip-shaped metal current collector coated with an electrode material. The function of the current collector is an electrical contact connection of the electrode material over the largest possible surface area. They are generally composed of a strip-shaped flat metal substance such as a metal foil or a metal foam or a metal-coated cloth.

[0066] For the electrical contact connection between the housing part and the electrodes, these current collectors can be welded directly to the housing part, preferably to the inside of the base of the housing part. Alternatively, the current collectors can also be welded to a separate electrical conductor, which is then electrically connected to the housing part.

[0067] In particular, as electrode materials for the electrodes of the cells according to the present invention, all materials capable of taking in and then releasing lithium ions are conceivable. For the negative electrode of a secondary lithium ion system, carbon-based materials such as graphite, or non-graphite carbon-based materials capable of lithium intercalation are particularly suitable. For the positive electrode of a secondary lithium ion system, for example, lithium metal oxide compounds and lithium metal phosphate compounds (such as LiCoO2 and LiFePO4) are conceivable.

[0068] The electrode can further include an electrode binder and a conductive agent. The electrode binder serves to ensure the mechanical stability of the electrode, for the mutual contact connection of the particles of the electrochemically active material, and for its contact connection with the current collector. A conductive agent such as carbon black enhances the electrical conductivity of the electrode.

[0069] The electrode is preferably impregnated with a suitable electrolyte.

[0070] The present invention further includes a method for manufacturing the above-described electrochemical cell according to the present invention. In principle, this manufacturing method mainly differs from the conventional method for manufacturing a cylindrical cell by the use of the above-described first contact lug including a first contact connection area mounted on the end face, and a second contact connection area mounted on the end face, in addition to a damping area intervening therebetween.

[0071] Preferably, according to the manufacturing method, electrodes made correspondingly in the form of a composite winding, for example, in a manner known per se, are introduced into the interior of the housing of a cylindrical cell, the housing is closed and optionally sealed, and the electrodes are in contact connection with the poles or end faces of the cylindrical cell. On at least one of the end faces of the cylindrical cell, a contact lug (first contact lug) having a damping zone is fixed, where the fixing of the contact lug to the end face of the housing is carried out exclusively in the first contact connection zone. For this purpose, for example, a plurality of weld points can be provided, which are formed by welding using resistance welding or laser welding methods. The damping zone of the contact lug following the first contact connection zone is not directly connected to the end face and can thus vibrate freely. At the end of this damping zone, a second contact connection zone is provided, which is provided for the contact connection of the external electrical conductor and the contact lug, and thus of each pole of the cell, in a manner known per se.

[0072] Further features and advantages of the present invention will become apparent from the following description of exemplary embodiments in conjunction with the drawings. The individual features can be realized either alone or in combination with each other.

Brief Description of the Drawings

[0073]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Best Mode for Carrying Out the Invention

[0074] FIG. 1 shows a perspective view of a button cell 1 from the prior art. The upper end face 2 that can be seen here constitutes the cathode of the button cell 1, and the end face (not visible) facing downward constitutes the anode of the button cell 1. A contact lug 3 is fixed to the end face 2, and it is divided into a flat first contact connection area 4 and a second contact connection area 5 in the form of contact spikes. The contact lug is fixed to the end face 2 of the button cell 1 in the first contact connection area 4. The connection to an external electrical conductor is carried out by the second contact connection area 5. In this case, the external electrical conductor is understood as an electrical conductor to which the cell is directly or indirectly connected, for example, to a circuit board or the like. The button cell 1 further includes a further contact lug 6. The further contact lug 6 is divided into a first contact connection area 7 fixed to the end face facing downward of the contact lug 6, an angled contact lug area 8, and a further contact connection area 9 where the contact connection with the external electrical conductor can be carried out in the region of the opposite end face 2. This type of button cell is known, for example, from EP3667761A1.

[0075] FIG. 2 shows a contact lug 3 that is similarly known from the prior art and structured in principle like the contact lug 3 according to FIG. 1. The first contact connection area 4 of the contact lug 3 is fixed to the end face 2 of the button cell by four individual weld points 41. The second contact connection area 5, in this form of the contact lug 3, is positioned at an angle to the plane of the end face 2 and thus simultaneously to the plane of the first contact connection area 4, and the second contact connection area 5 is clearly accessible for contact connection with the external electrical conductor.

[0076] The configuration of the contact lug according to the present invention represented in FIGS. 3 to 5 by the provision of each attenuation area within the contact lug solves the problem that the contact lug 3 according to the prior art is particularly susceptible to impacts and vibrations.

[0077] Figure 3 shows a particularly preferred embodiment of the contact lug 20 according to the invention, provided on the end face 2 of the button cell 200. The contact lug 20 includes a first contact connection area 24 having individual weld points 241 for fixing the contact lug 20 to the end face 2 of the button cell 200. A second contact connection area 25 mounted on the end face is further provided for the contact connection of an external electrical conductor with the cylindrical cell 200. An attenuation area 26 is provided between the first contact connection area 24 and the second contact connection area 25, which in this embodiment is in strip shape and has a width narrower than that of the first contact connection area 24. The contact lug includes a transition 28 from the first contact connection area 24 to the attenuation area 26, where the width of the contact lug decreases such that the cross-sectional area of the contact lug is reduced by at least 50%. The second contact connection area 25 is curved by 90° and is thus oriented perpendicular and axially to the first contact connection area 24 and the attenuation area 26. Immediately after the curved transition to the second contact connection area 25, the attenuation area 26 tapers further.

[0078] Figure 4 shows an even more particularly preferred embodiment of the contact lug 30 according to the invention. In addition to the first contact connection area 34 having individual contact points or weld points 341 used for fixing the contact lug 30 to the end face 2 of the button cell 300, the contact lug 30 further includes, in this case, a second contact connection area 35, which is curved by 90° for the electrical contact connection of an external electrical conductor with the cell 300. An attenuation area 36 is provided between the first contact connection area 34 and the second contact connection area 35, which in this embodiment takes the form of a curved strip. In this configuration, the curved shape of the attenuation area 36 is achieved by two directional changes in the profile of the attenuation area 36. The contact lug includes a transition 38 from the first contact connection area 34 to the attenuation area 36, where the width of the contact lug decreases such that the cross-sectional area of the contact lug is reduced by at least 50%.

[0079] Figure 5 shows a further particularly preferred embodiment of the contact lug 40 having the first contact connection area 44, which is fixed to the end face 2 of the cylindrical cell 400 by four weld points 441 or comparable contact points. At the other end of the contact lug 40, a second contact connection area 45 is provided, by means of which a contact connection to an external electrical conductor can be effected. In the view shown in Figure 5, the angling of the second contact connection area 45 can be seen. Thus, the second contact connection area 45 is curved at approximately right angles from the plane in which the first contact connection area 44 and the damping area 46 are located. The boundary between the second contact connection area 45 and the damping area 46 extends along the bending line 58. The damping area 46 has a strip-shaped curved profile, which describes approximately three quarters of a circle. This curvature of the damping area 46 results in a relatively long damping area 46 being configured with simultaneously restricted space conditions. Impacts or vibrations can thus be optimally damped.

[0080] The circular curvature, in particular the arc, of the damping area 46 can be used for other purposes, in particular for further enabling the exposure or recess of the central area of the end face 2 of the cylindrical cell 400. In the configuration of the cylindrical cell 400 shown in Figure 6, in particular in this central area of the end face 2, a safety valve 50 is provided in the form of a rupture membrane. As a result of the circular curvature and the arc of the damping area 46, the safety valve 50 is not obstructed and no further rupture process is impaired.

[0081] In this embodiment, the second contact connection area 45 includes two lateral wings 47, by means of which the contact connection to an external electrical conductor can be supported by a crimping process or a clamping method, in which the wings 47 are bent around the electrical conductor.

[0082] As a whole, compared with the conventional contact lugs (see, for example, FIGS. 1 or 2), the service life of the fixed points of the first contact connection area can be extended by the first contact lug of the cylindrical cell according to the invention, which is characterized by the damping area, and the impact or vibration that damages the fixed points is mitigated. The same principle also applies to the connection of the second contact connection area. Thus, the damping area deflects the impact or vibration from the contact connection area of the contact lug.

[0083] In each of FIGS. 3 and 4, a further contact connection area 9 of the second contact lug can be seen, which leads the contact from the opposite end face to the plane of the end face 2 around the outer shell surface of the cylindrical cell so that the cells 200 and 300 can be contact-connected in a particularly simple manner, for example on a circuit board.

Claims

[Claim 1] Electrochemical cells (200; 300; 400) having the following characteristics (a) to (d) and further having the following characteristics (e) to (h): (a) the cell includes a cylindrical housing enclosing an interior space, the cylindrical housing having a first end surface (2) and a second end surface, the end surfaces being interconnected by an annular shell; (b) a positive electrode and a negative electrode are disposed within the housing; (c) the negative electrode is electrically connected to the first end face (2) directly or by a separate electrical conductor to form a cathode, and the positive electrode is electrically connected to the second end face (2) directly or by a separate electrical conductor to form an anode; (d) contact lugs (20; 30; 40) fixed to the first or second end face (2) of the housing; (e) the contact lug (20; 30; 40) comprises a first contact connection section (24; 34; 44) attached to the end face, where the contact lug is fixed to the end face (2); (f) the contact lug (20; 30; 40) comprises a second contacting section (25; 35; 45) mounted on the end face for contacting an external electrical conductor with the electrochemical cell; (g) the contact lug (20; 30; 40) between the first contact-connection area (24; 34; 44) and the second contact-connection area (25; 35; 45) includes a damping area (26; 36; 46) capable of vibrating freely; (h) the first contact-connection section (24; 34; 44) and the damping section (26; 36; 46) extend in a plane parallel to the plane of the end face (2) of the housing in which the contact lug is fixed, and the second contact-connection section (25; 35; 45) extends at an angle to said plane, or the second contact-connection section (25; 35; 45) and the damping section (26; 36; 46) are arranged in the same plane.

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