Electrochemical cell with contact lugs

Abstract

To provide an electrochemical cell incorporating an improved contact lug.SOLUTION: There is provided an electrochemical cell 400 having the following features: (a) a cell includes a cylindrical housing that encloses an interior space, the cylindrical housing having a first end face 2 and a second end face which are interconnected by an annular shell; (b) a positive electrode and a negative electrode are arranged in the interior of the housing; (c) the negative electrode is electrically connected, either directly or via a separate electrical conductor, to the first end face 2 to constitute a negative pole, and the positive electrode is electrically connected, either directly or via a separate electrical conductor, to the second end face to constitute a positive pole; and (d) a contact lug 40 is fastened to the first or second end face of the housing.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 technology]

[0002] The function of electrochemical cells is energy storage. They contain a positive electrode and a negative electrode, which are separated from each other by a separator. In this type of energy storage cell, the electrochemical and energy-releasing reaction occurs, consisting of two electrically interconnected but spatially separated partial reactions. One partial reaction, occurring at a relatively low redox potential, proceeds at the negative electrode. The other partial reaction, occurring at a relatively high redox potential, occurs at the positive electrode. During discharge, electrons are released at the negative electrode by an oxidation process, resulting in an electron flow that flows to the positive electrode via an external load, where a corresponding amount of electrons are absorbed. Therefore, a reduction process occurs at the positive electrode. Simultaneously, for charge equalization purposes, an ionic flow corresponding to the electrode reaction exists within the cell. This ionic flow passes through the separator and is transported by the ionically conductive electrolyte.

[0003] In secondary (rechargeable) electrochemical energy storage cells, this discharge reaction is reversible, so that the conversion of chemical energy to electrical energy associated with discharge can be reversed.

[0004] Small cells, such as button cells, have a particularly large number of applications. Button cells are, by definition, cells with a height less than their diameter. They generally include a cylindrical housing, which is composed of two metal housing parts, which are electrically insulated from one another, one of which is connected as an anode and the other as a cathode. The housing generally includes first and second end faces, which are each circular or elliptical in shape and interconnected by an annular shell.

[0005] Contact lugs are frequently required to fasten cells such as button cells in electronic devices (e.g., circuit boards). The contact lugs function primarily as mechanical fastening means and secondarily as electrical conductors. Generally, one contact lug is connected to the anode and the second contact lug is connected to the cathode. The connection of the button cell to the housing is carried out, inter alia, by soldering or welding.

[0006] For technical manufacturing reasons, the contact lugs are generally fitted to the end faces of the button cells.

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

[0008] Cells with contact lugs are known, for example, from EP 3667761 A1 and US 2011 / 001618 A1.

[0009] In recent years, rechargeable button cells have been developed based on lithium-ion technology (see, for example, WO 2010 / 089152 A1). Button cells of this type require high safety measures because, in the event of damage, their high energy density and easily combustible components can constitute a major danger to consumers.

[0010] Known safety measures for button cells include the formation of a fracture surface in one of their end faces, such that in the event of excessive pressure occurring within the cell above a pressure threshold, the housing of the button cell can open in a controlled manner in the region of the fracture surface, releasing the excess pressure.

[0011] However, this type of fracture surface is easily sealed by welding a contact lug to the end face containing the fracture surface.

[0012] A further problem occurs in cells having contact lugs, where the contact lugs can become detached from the respective end faces to which they are fixed in response to the oscillations or vibrations to which they are subjected. Summary of the Invention

[0013] The present invention addresses the above-mentioned problems by providing an electrochemical cell comprising improved contact lugs, which exhibit greater resistance to the above-mentioned mechanical loads and / or are characterized by improved safety, especially in combination with the above-mentioned pressure relief valves such as fracture surfaces.

[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.

[0015] The electrochemical cell according to the invention is primarily characterized by the following features: (a) the cell includes a cylindrical housing enclosing an interior space, the cylindrical housing having a first end surface 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 surface, either directly or by a separate electrical conductor, to form a cathode, and the positive electrode is electrically connected to the second end surface, either directly or by a separate electrical conductor, to form an anode. (d) a contact lug is secured to the first or second end surface of the housing;

[0016] According to the invention, the electrochemical cell is further characterized by the following features with respect to the contact lugs: (e) the contact lug includes a first contact connection area attached to the end surface, where the contact lug is fixed to the end surface; (f) the contact lug includes a second contact connection area attached to the end surface 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 that can vibrate freely; (h) The first contact-connection area and the damping area extend in a plane parallel to the plane of the end face of the housing to which the contact lug is fixed, the second contact-connection area preferably extending at an angle to said plane.

[0017] Due to the configuration of the contact lugs, which have a first contact-connection area attached to the end face for fixing the contact lugs to the end face and a second contact-connection area attached to the end face for contacting an external electrical conductor, in particular with the intervening damping area, the cell according to the invention achieves a significant improvement in the shock and vibration sensitivity of electrochemical cells. In particular, due to the damping area in the central region of the contact lugs, shocks and vibrations to which the contact lugs are exposed can be buffered and damped so that not all of the magnitude of said shocks or vibrations is imparted to the contact-connection areas, in particular the first contact-connection area, so that the contact-connection areas, in particular the first contact-connection area, are substantially protected against vibrations.

[0018] The fixing of the contact lugs in the first contact-connection area is typically carried out by welding, e.g., laser welding, but in a particularly advantageous manner, resistance welding is used for this purpose. For this purpose, a plurality of welds, e.g., two, four, or six welds, can be provided in the first contact-connection area. In conventional electrochemical cells, a problem can arise in that, as a result of shocks or vibrations acting on the cell, one or more of these welds are damaged, thus potentially resulting in loosening or even detachment of the contact lugs from the end face. In the electrochemical cell according to the invention, this problem is reduced, as shocks or vibrations acting on the contact lugs are cushioned and damped by the damping sections arranged between the contact-connection areas attached to the end face.

[0019] The contact lugs of the cell according to the invention described above can replace conventional contact lugs, which consist only of a flat contacting area (first contacting area) where the contact lug is fixed to the end face of the cell, and a contact spike by which the electrochemical cell can be contacted with an external electrical conductor. The contact spike is typically configured directly on the flat contacting area in the form of a narrow protrusion and can be angled so that the external electrical conductor can be soldered or clamped to the contact spike. An example of a contact lug with a non-angled contact spike is shown in Figure 1 (reference number 106) of EP 3 667 761 A1.

[0020] By damping shocks or vibrations with the damping section, the connection between the second contact-connection section and the external electrical conductor can also be protected, thus preventing fatigue or defects and / or cracks from appearing at, for example, the soldering or clamping points between the second contact-connection section and the external electrical conductor.

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

[0022] As mentioned above, in preferred embodiments, the second contact-connection area extends at an angle 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 relative to the first contact-connection area and the damping area. A 90° angle 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 onto which the contact lug is bent. 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 invention preferably have a circular or elliptical peripheral shape and are interconnected by an annular shell.

[0024] In the manufacture of cylindrical cells according to the invention, the first contact-connection area, the second contact-connection area, and the contact lug with the damping area disposed therebetween are preferably initially constructed as flat components, e.g., stamped sheet metal parts, with all of these areas being arranged in a single plane. In this form, the contact lug can be fixed to the end face of the cell at the first contact-connection area. Bending or angling the second contact-connection area to facilitate connection of the external electrical conductor with the second contact-connection area does not need to be carried out until a later stage.

[0025] Alternatively, the bending or angling can also be performed before the fixing of 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 a cylindrical electrochemical cell which constitutes the cathode of the cell.

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

[0028] According to the above-specified feature (a), the damping section is only indirectly connected to the end face, so that the damping section constitutes to some extent the freely vibrating range of the first contacting section, which freely vibrating range forms a transition to the second contacting section attached to the end face, via which contacting of the electrochemical cell to an external electrical conductor can be performed.

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

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

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

[0032] It is further preferred that the strip-shaped section or damping section, in particular the strip-shaped damping section, having an essentially constant width exceeds the maximum length of the first contact-connection section by at least 1.1 times, particularly preferably by at least 2 times, in particular by 3 times.

[0033] The presence of a transition from the first contact connection area to the damping area does not preclude, at least locally, a further increase in the width, i.e. cross section, of the contact lug within the damping area.

[0034] The change in width of the contact lug at the transition can be configured to increase gradually or continuously. By this configuration of the damping section, vibrations or shocks originating from the second contact-connection section acting on the contact lug can be damped and attenuated in a particularly effective manner before they reach the first contact-connection section.

[0035] In a particularly preferred configuration, the attenuation zone is characterized by the following features: (a) The damping section has a curved profile, in particular a circular profile.

[0036] The curved profile of the damping section offers the particular advantage that relatively long lengths of the damping section can be achieved, whereby the limited surface area of the end faces of the cylindrical cells can be optimally utilized. Due to the extension of the damping section that is thus made possible, shocks or vibrations can be damped even more effectively. The damping section in the contact lug may be somewhat track or strip shaped and may preferably be curved. The curved profile may preferably follow a circular arc. For example, the damping section may take the approximate form of a three-quarter circle.

[0037] The configuration of the damping section with a curved profile further provides additional special advantages: in particular, the curved profile allows the contact lug to leave the central area of the end face empty so that it 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 following specified features (a) to (c): (a) the cell includes a safety valve; (b) the cell includes a safety valve in the form of a fracture surface; (c) The damping area takes on a curved profile around the relief valve.

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

[0040] Known safety means for cells, in particular button cells, are provided in which a safety valve, in particular in the form of a break surface, is included in one of the end faces, which constitutes a predetermined breaking point and in the event of excessive pressure building up in the cell exceeding a certain pressure threshold, the safety valve (e.g., break surface) can open so that the excess pressure can be released.

[0041] In a particularly preferred embodiment of the invention, the above-mentioned empty central region of the end face is used for safety purposes, in particular for the location of a safety valve. It is particularly advantageous for the safety valve, in particular the fracture surface, to be located in a region of the end face, in particular in the central region, which is kept empty by the curved profile of the contact lug. It is thus achieved that the fracture surface, or optionally a differently configured safety valve, is not obstructed by the contact lug.

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

[0043] As noted above, each of the first and second end faces of a cell according to the present invention preferably has a circular or elliptical peripheral shape and are 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. Because the second contact-connection area does not engage with the end face but is angled therefrom or projects beyond the edge of the end face to which it is fixed, it is particularly accessible for contact-connection and therefore allows particularly simple connection to external electrical conductors. 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, thereby establishing contact with each pole of the cell according to the invention.

[0045] In a particularly preferred manner, the cell according to the invention is characterized by the additional features (a) and (b) specified below: (a) the cell includes a contact lug fixed to the first or second end surface of the housing as a first contact lug; (b) the cell includes a second contact lug on an end face of the housing located opposite 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 may further comprise a further contact lug fixed to the opposite end face. As mentioned above, the contact lug may in a preferred embodiment be led to the side of the opposite end face by bending it through 90°. Correspondingly, the cell according to the invention is preferably characterized by the additional feature (a) specified below: (a) The second contact lug extends across an angled contact lug area in the plane of the opposite end face.

[0047] Due to the angled contact lug areas, contacting of the two poles of the cylindrical cell can be carried out in a particularly feasible manner from one side of the cell, and this configuration of the cylindrical cell according to the invention therefore allows, for example, for simple fixing of the cell to a circuit board in a particularly preferred configuration.

[0048] The second contact lug may for example be configured like the contact lug identified by reference number 107 in Figure 2 of the above-mentioned EP 3 667 761 A1.

[0049] In conventional cylindrical cells, the first contact lug is a relatively small component, consisting essentially of only 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 cause difficulties in the cell manufacturing process, because it is difficult to handle during the fixing of the contact lug to the end face. Conversely, the contact lug with a damping area according to the present invention offers the special advantage that the pick-up selection for the contact lug in the manufacturing process of cylindrical cells, especially in automated manufacturing, is significantly improved and consequently simplified. Therefore, the cell according to the present invention is also particularly advantageous in terms of manufacturing and its manufacturing costs. Therefore, the cell according to the present invention is particularly suitable for automated manufacturing.

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

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

[0052] Preferably, the contact lug(s) are very thin sheet material pieces. In particularly preferred embodiments, the contact lug(s) of the cylindrical cells according to the invention may comprise the following additional features with respect to the thickness of the contact lug: (a) The contact lug(s) have a thickness in the range of 0.05 mm to 2.5 mm, preferably 0.25 mm to 2.5 mm.

[0053] A thickness of the contact lug within the above-mentioned range ensures sufficient stability of the contact lug, while this thickness of the contact lug ensures sufficient vibration capacity of the first contact lug in its damping zone, so that shocks or vibrations acting on the first contact lug can be damped and attenuated in a particularly effective manner.

[0054] Metallic materials are particularly suitable as contact lug materials. In particularly preferred embodiments, the cylindrical cells according to the invention may include the following additional features relative to the material used for the contact lug(s): (a) The contact lug(s) are made of steel, in particular special steel.

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

[0056] Alternatively, the contact lug(s) may also be made 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 variety of applications in a particularly advantageous manner. In connection with lithium-ion cells, the configuration of the first contact lug according to the invention further offers the advantage that the safety aspects of the lithium-ion cell are also taken into account in a specific way. In particular, the first contact lug according to the invention offers the option of configuring the damping section in a particularly curved form so that the safety valve, in particular the fracture surface, is not obstructed.

[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 cells have diameters ranging from 5 mm to 25 mm; (c) The cells have a height in the range of 1.5 mm to 15 mm, preferably 3 mm to 15 mm.

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

[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, each preferably including a hollow cylindrical shell in addition to a preferably circular base, the outside of which preferably constitutes the end face mentioned above.

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

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

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

[0064] The end faces of the composite winding are preferably formed by the longitudinal edges of at least one separator strip and are oriented toward the circular, mutually parallel housing base, so that the winding axis is oriented vertically or essentially parallel to the housing base. The winding axis and the cylindrical axis preferably coincide. An exemplary composite winding of this type is described in particular in WO 2010 / 089152 A1.

[0065] Both the positive and negative electrodes preferably comprise strip-shaped metal current collectors coated with electrode material. The function of the current collectors is to provide electrical contact for the electrode material over the largest possible surface area. They generally consist of strip-shaped flat metal materials, such as metal foils or metal foams or metal-coated fabrics.

[0066] For electrical contact connection of the housing parts and the electrodes, these current collectors can be welded directly to the housing parts, preferably to the inside of the base of the housing parts, or alternatively, the current collectors can also be welded to separate electrical conductors, which are then electrically connected to the housing parts.

[0067] In particular, all materials capable of absorbing and subsequently releasing lithium ions are contemplated as electrode materials for the electrodes of the cell according to the invention. For the negative electrode of the secondary lithium-ion system, carbon-based materials such as graphite or non-graphitic carbon-based materials capable of lithium intercalation are particularly suitable. For the positive electrode of the secondary lithium-ion system, for example, lithium metal oxide compounds and lithium metal phosphate compounds (e.g., LiCoO2 and LiFePO4) are contemplated.

[0068] The electrode may further comprise an electrode binder and a conductive agent. The electrode binder ensures the mechanical stability of the electrode and serves to connect the particles of the electrochemically active material to each other and to the current collector. The conductive agent, such as carbon black, enhances the electrical conductivity of the electrode.

[0069] The electrodes are preferably impregnated with a suitable electrolyte.

[0070] The present invention further includes a method for producing the above-described electrochemical cell according to the invention, which in principle differs from conventional methods for producing cylindrical cells mainly by the use of the above-described first contact lugs, which comprise a first contacting area attached to the end face and a second contacting area attached to the end face, as well as a damping area interposed therebetween.

[0071] Preferably, according to the manufacturing method, in a manner known per se, a correspondingly produced electrode, for example in the form of a composite winding, is introduced into the housing of the cylindrical cell, the housing is closed and optionally sealed, and the electrode is contact-connected with the pole or end face 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 section is fixed, whereby the contact lug is fixed to the end face of the housing exclusively in the first contact-connection section. For this purpose, for example, a plurality of welds can be provided, which are formed by resistance welding or laser welding. The damping section of the contact lug following the first contact-connection section is not directly connected to the end face and can therefore vibrate freely. At the end of this damping section, a second contact-connection section is provided, which, in a manner known per se, provides for the contact connection of the contact lug and thus the respective pole of the cell with an external electrical conductor.

[0072] Further features and advantages of the invention will become apparent from the following description of exemplary embodiments in conjunction with the drawings, in which: The individual features can be realized either alone or in combination with one another. [Brief explanation of the drawings]

[0073] [Figure 1] FIG. 1 shows a perspective view of a button cell from the prior art, having a first contact lug and a second contact lug. [Figure 2] FIG. 2 shows a perspective view of a (partial) contact lug from the prior art fixed to one end face of a cylindrical cell. [Figure 3] FIG. 3 shows a diagram of a contact lug fixed to one end face of a cylindrical cell in a preferred embodiment of the invention. [Figure 4] FIG. 4 shows a diagram of a contact lug fixed to one end face of a cylindrical cell according to a further preferred embodiment of the invention. [Figure 5] FIG. 5 shows a perspective view of a further preferred embodiment of a (partial) contact lug according to the invention fixed to one end face of a cylindrical cell. DETAILED DESCRIPTION OF THE INVENTION

[0074] FIG. 1 shows a perspective view of a button cell 1 from the prior art. The upper end face 2, visible here, constitutes the cathode of the button cell 1, while the downward-facing end face (not visible) constitutes the anode of the button cell 1. Contact lugs 3 are fixed to end face 2, which is divided into a flat first contact-connection area 4 and a second contact-connection area 5 in the form of a contact spike. The contact lugs are fixed to end face 2 of the button cell 1 in the first contact-connection area 4. The connection to an external electrical conductor is made via second contact-connection area 5. In this case, an external electrical conductor is understood as an electrical conductor to which the cell is connected, for example, directly or indirectly to a circuit board or the like. The button cell 1 further comprises a further contact lug 6, which is divided into a first contact-connection area 7, where the contact lug 6 is fixed to the downward-facing end face, an angled contact lug area 8, and a further contact-connection area 9, where a contact connection with an external electrical conductor can be made in the region of the opposite end face 2. A button cell of this type is known, for example, from EP 3 667 761 A1.

[0075] Figure 2 shows a contact lug 3 which is also known from the prior art and which is structured in principle like the contact lug 3 according to Figure 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 welds 41. In this form of contact lug 3, the second contact-connection area 5 is located in the plane of the end face 2 and therefore at an angle to the plane of the first contact-connection area 4, so that the second contact-connection area 5 is clearly accessible for contacting with an external electrical conductor.

[0076] The contact lug configuration according to the invention represented in Figures 3 to 5 by the respective provision of damping zones within the contact lug solves the problem that the prior art contact lugs 3 are particularly susceptible to shocks and vibrations.

[0077] FIG. 3 shows a particularly preferred embodiment of a contact lug 20 according to the invention, provided on the end face 2 of a button cell 200. The contact lug 20 comprises a first contact-connection section 24 with individual welds 241 that secure the contact lug 20 to the end face 2 of the button cell 200. A second contact-connection section 25, attached to the end face, is further provided for contacting the cylindrical cell 200 with an external electrical conductor. Between the first and second contact-connection sections 24 and 25, a damping section 26 is provided, which in this embodiment is strip-shaped and narrower than the first contact-connection section 24. The contact lug comprises a transition section 28 from the first contact-connection section 24 to the damping section 26, where the width of the contact lug decreases so that the cross-sectional area of the contact lug is reduced by at least 50%. The second contact-connection section 25 is curved by 90° and is therefore oriented perpendicularly and axially to the first contact-connection section 24 and the damping section 26. Immediately beyond the curved transition to the second contact connection section 25, the damping section 26 tapers further.

[0078] 4 shows a further particularly preferred embodiment of a contact lug 30 according to the invention. In addition to the first contact-connection section 34 with individual contact or welding points 341 used for fastening the contact lug 30 to the end face 2 of the button cell 300, the contact lug 30 further comprises a second contact-connection section 35, which in this case is bent by 90° for electrical contact-connection of the cell 300 with an external electrical conductor. Between the first and second contact-connection sections 34 and 35, a damping section 36 is provided, which in this embodiment has the shape of a curved strip. In this configuration, the curved shape of the damping section 36 is achieved by two directional changes in the profile of the damping section 36. The contact lug comprises a transition section 38 from the first contact-connection section 34 to the damping section 36, where the width of the contact lug decreases so that the cross-sectional area of the contact lug is reduced by at least 50%.

[0079] FIG. 5 shows a further particularly preferred embodiment of the contact lug 40, which has a first contact-connection area 44, which is fixed to the end face 2 of the cylindrical cell 400 by four welds 441 or equivalent contact points. The other end of the contact lug 40 is provided with a second contact-connection area 45, by means of which a contact connection with an external electrical conductor can be established. The angle of the second contact-connection area 45 can be seen in the view shown in FIG. 5. Therefore, the second contact-connection area 45 is curved approximately at a right angle from the plane in which the first contact-connection area 44 and the damping area 46 lie. The boundary between the second contact-connection area 45 and the damping area 46 extends along a 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 allows for a relatively long damping area 46, while at the same time minimizing space requirements. Shocks or vibrations can thus be optimally damped.

[0080] The circular curvature, and in particular the arc, of the damping zone 46 further allows the exposure or recession of a central region, in particular of the end face 2 of the cylindrical cell 400, which can be used for other purposes. In the configuration of the cylindrical cell 400 shown in Figure 6, a safety valve 50 is provided in the form of a rupture membrane, in particular in this central region of the end face 2. As a result of the circular curvature and the arc of the damping zone 46, the safety valve 50 is not obstructed and any rupture process is not impaired.

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

[0082] Overall, compared to conventional contact lugs (see, for example, Figures 1 or 2), the first contact lug of the cylindrical cell according to the invention, which is characterized by a damping zone, allows the service life of the fastening point of the first contact-connection zone to be extended and shocks or vibrations that would otherwise damage said fastening point are damped. The same applies in principle to the connection of the second contact-connection zone. The damping zone thus deflects shocks or vibrations away from the contact-connection zone of the contact lug.

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

Claims

1. Electrochemical cells (200; 300; 400) having the following characteristics (a) to (d) and further having the following characteristics (e) to (k): (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 surface (2) directly or via a separate electrical conductor to form a cathode, and the positive electrode is electrically connected to the second end surface (2) directly or via 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) attached to 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 free vibration; (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 in which the contact lug is fixed, and the second contact-connection area (25; 35; 45) extends at an angle to said plane, or the second contact-connection area (25; 35; 45) and the damping area (26; 36; 46) are arranged in the same plane, (i) the cell is a button cell; (j) the cell (400) includes a safety valve in the form of a fracture surface; (k) The damping section (36; 46) takes on a curved annular profile around the safety valve in the form of a fracture surface.

2. 10. The electrochemical cell of claim 1 having the following additional feature (a): (a) The damping section (26; 36; 46) is not directly connected to the end face (2) to which the contact lug is fixed.

3. 3. The electrochemical cell of claim 1 or 2, having at least one of the following additional features (a) to (c): (a) the damping zone (26; 36; 46) is configured in the shape of a strip; (b) the attenuation region includes at least one strip-shaped region of essentially constant width; (c) the contact lug comprises a transition zone from the first contact connection zone (24; 34; 44) to the damping zone (26; 36; 46), in which the width of the contact lug is reduced such that the cross section of the contact lug is reduced by at least 30%.

4. Electrochemical cell according to any one of claims 1 to 3, 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.

5. Electrochemical cell according to any one of claims 1 to 4, having the following additional features (a) and (b): (a) the cell comprises, 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 comprises a second contact lug on the end face of the housing located opposite to the end face (2) on which the first contact lug (20; 30; 40) is fixed.

6. 6. The electrochemical cell of claim 5, having the following additional feature (a): (a) The second contact lug (6) extends over an angled contact lug area (8) in the plane of the opposite end face (2).

7. Electrochemical cell according to any one of claims 1 to 6, having the following additional feature (a): (a) The cell is configured to be fixed to a circuit board.

8. 8. An electrochemical cell according to any one of claims 1 to 7, having at least one of the following additional features (a) and (b): (a) the contact lug (20; 30; 40)(s) is / are a sheet metal part; (b) The contact lug(s) (20; 30; 40) are stamped parts.

9. Electrochemical cell according to any one of claims 1 to 8, having the following additional feature (a): (a) The contact lug(s) (20; 30; 40) have a thickness in the range of 0.05 mm to 2.5 mm.

10. 10. An electrochemical cell according to any one of claims 1 to 9, having the following additional feature (a) or (b): (a) the contact lug(s) (20; 30; 40) are made of steel, in particular special steel; (b) The contact lug(s) (10; 30; 40) are made of nickel or nickel-plated metal or nickel alloy.

11. Electrochemical cell according to any one of claims 1 to 10, having the following additional features: (a) The cell is a lithium ion cell.

12. 12. The electrochemical cell of any one of claims 1 to 11, having at least one of the following additional features (a) to (b): (a) the cells have a diameter in the range of 5 mm to 25 mm; (b) the cells have a height in the range of 1.5 mm to 15 mm;

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