Contact element for electrically conductive contact of battery cell housing

Abstract

The invention relates to a contact element (1) for electrically conductive contact of a battery cell housing (5), comprising: a substrate (9) made of an electrically conductive material; a plurality of spring arms (11) made of an electrically conductive material, wherein the spring arms (11) project at different positions of the base plate (9) and together delimit a housing receptacle (13) for receiving the electrically conductive cylindrical end portion (3) of the battery cell housing (5); a spring ring (15), which is designed to be tensioned around the spring arm (11) in such a way that the spring arm is pressed against the circumferential surface (14) of the end part (3) received by the housing receptacle (13), the spring ring (15) being a slotted ring with two ring ends (17a, 17b) and the spring ring (15) having a larger diameter in the pretensioned state than in the relaxed state, the spring ring (15) being designed to be tensioned around the spring arm (11) in such a way that the spring ring (15) is pressed against the circumferential surface (14) of the end part (3) received by the housing receptacle (13). The ring ends (17a, 17b) abut against each other in the circumferential direction of the spring ring (15) in the preloaded state in order to prevent the spring ring (15) from undesirably loosening.

Description

Technical Field

[0001] The invention relates to a contact element for electrically conductively contacting a battery cell housing. The invention also relates to a method for electrically conductively contacting at least one battery cell housing, a holding system for carrying out the method, a battery cell and a battery module. Background Art

[0002] Batteries in the form of round cells usually contain a cylindrical cell housing made of an electrically conductive material. For electrically conductive contacting of the end sections of the cell housing, a cell connector with a receptacle consisting of a plurality of spring arms can be used, for example. If the end section is introduced into the receptacle, the spring arms are pushed radially apart from one another, i.e. pressed against the circumference of the end section. The cell connector can be made of a specific alloy that exhibits a compromise between good electrical conductivity and good elasticity.

[0003] DE 10 2019 007 869 A1 describes an example of such a unit connector. Summary of the invention

[0004] The object of the present invention is to improve the contacting of a battery cell housing.

[0005] This technical problem is solved by the subject matter of the independent claims. Advantageous embodiments of the invention are set forth in the dependent claims, the following description and the drawings.

[0006] A first aspect of the present invention relates to a contact element for electrically conductively contacting a battery cell housing, comprising a cylindrical end portion made of an electrically conductive material. The contact element comprises: a base plate made of an electrically conductive material; a plurality of spring arms made of an electrically conductive material, wherein the spring arms extend at different positions of the base plate and together define a boundary of a housing receiving portion for receiving the end portion; a spring ring, which is tensioned around the spring arms so that the spring arms are pressed against the (outer) circumference of the end portion received by the housing receiving portion, wherein the spring ring is a slotted ring with two ring ends, and the spring ring has a larger diameter in a pre-tensioned state than in a relaxed state, wherein the ring ends abut against each other in a circumferential direction of the spring ring in the pre-tensioned state to prevent the spring ring from undesirably relaxing.

[0007] Suitably the diameter of the pre-tensioned spring ring is large enough so that the spring ring can slide over the spring arm without further expanding or overbending the spring arm.

[0008] The spring ring can be activated in the following way, that is, the ring ends are offset from each other laterally (i.e., along the central axis direction of the spring ring) until the ring ends no longer abut each other, so that the spring ring can relax. The ring ends are activated, i.e., the at least partially relaxed spring ring can at least partially overlap in its circumferential direction.

[0009] The battery cell housing can be designed to receive different components of the battery cell, such as a positive electrode, a negative electrode and a separator separating the electrodes from each other. The battery cell housing can be made of a metal material and / or be cylindrical.

[0010] By means of the activatable spring ring, excessive bending of the spring arm during the insertion of the end section into the housing receptacle and / or during operation of the battery cell can be prevented. Even small errors, such as an inexact centering of the end section relative to the housing receptacle, can have a significant influence on the insertion force and the deflection of the spring arm.

[0011] In other words, the spring ring limits the size of the opening of the housing receptacle and thus the bending force acting on the spring arm. The spring force is therefore not primarily defined by the characteristics of the spring arm, i.e. the geometry and material of the spring arm, but by the characteristics of the separate spring ring. The spring arm can thus be constructed largely independently of the desired spring force, which improves the installation process.

[0012] This also has the advantage that a certain degree of freedom is available in the choice of materials for the conductive parts of the contact element. For example, the base plate and the spring arms can be made of a material with particularly good electrical conductivity and / or particularly good solderability but a low modulus of elasticity (e.g. copper), while the spring ring can be made of a material with particularly high elasticity or a particularly high modulus of elasticity but poor electrical conductivity and / or poor solderability (e.g. spring steel). Conventional (one-piece) contact elements are usually made of bronze, which offers a compromise in terms of electrical conductivity, solderability and elasticity.

[0013] The spring ring makes it difficult for the spring arms to bend outwards or prevents this. This also increases installation safety. For example, a short circuit in the battery module caused by a spring arm bending outwards can be prevented.

[0014] A second aspect of the invention relates to a method for electrically conductive contacting of at least one battery cell housing. The method comprises: providing a first battery cell housing with a cylindrical first end portion made of an electrically conductive material; providing a contact element as described above and below, wherein a prestressed spring ring surrounds a spring arm defining a housing receptacle; introducing the first end portion into the housing receptacle; activating the spring ring by displacing the ring ends relative to one another in the direction of the spring ring center axis until the ring ends no longer abut against one another in the circumferential direction of the spring ring, so that the spring ring can relax, wherein the activated spring ring is tensioned around the spring arm, so that the spring arm is pressed against the (outer) circumference of the first end portion received by the housing receptacle.

[0015] In other words, the diameter of the housing receptacle is larger when the spring ring is not activated than when it is activated, or when the spring ring is in the preloaded state, it presses against the spring arm with a significantly lower force than in the activated state. This simplifies the positioning of the end section in the housing receptacle. Since the spring ring is only activated when the end section is correctly positioned in the housing receptacle, damage to the spring arm can be avoided, which typically occurs when the end section is not correctly positioned in the housing receptacle.

[0016] Here, by applying a first force to a first one of the ring ends in the direction of the central axis and by applying a second force directed in the opposite direction to the first force to a second one of the ring ends, the ring ends can be moved away from each other until the ring ends no longer abut against each other in the circumferential direction of the spring ring, i.e., can move relative to each other unhindered in the circumferential direction of the spring ring, and thus the spring ring relaxes.

[0017] When the end portion is received by the housing receiving portion, the center axis of the spring ring may, for example, be co-linear with the center axis of the end portion and / or the battery cell housing and / or the housing receiving portion.

[0018] A third aspect of the present invention relates to a battery cell. The battery cell can be manufactured by the method described above and below or by other methods. The battery cell comprises: a battery cell housing with a cylindrical end portion made of a conductive material; a contact element described above and below, wherein the end portion is received by a housing receiving portion and a spring ring is tensioned around a spring arm so that the spring arm is pressed against the (outer) circumference of the first end portion received by the housing receiving portion.

[0019] In the cell housing, various components of a battery cell for storing electrical energy, such as a positive electrode, a negative electrode and a separator separating the electrodes from one another, can be arranged. For example, the electrodes and separators can be stacked one on top of another, for example in the form of strips, and rolled into a roll. The cell housing can be made of a metal material and / or be cylindrical.

[0020] The battery cells may be rechargeable (round) cells, such as lithium-ion cells of a high voltage battery for powering an electric drive of a vehicle, such as a car, truck, bus or motorcycle.

[0021] Features of a battery cell may also be features of the method described above and below (and vice versa).

[0022] A fourth aspect of the present invention relates to a holding system for performing a method of an embodiment of the second aspect of the present invention described below. The holding system comprises: a first holding device for holding a first battery cell housing, wherein the first holding device comprises a first substrate with a first opening for introducing the first battery cell housing and a first protrusion, wherein the first protrusion protrudes from the end side of the first substrate with the first opening; a second holding device for holding a second battery cell housing, wherein the second holding device comprises a second substrate with a second opening for introducing the second battery cell housing and a second protrusion, wherein the second protrusion protrudes from the end side of the second substrate with the second opening.

[0023] It is possible that the first opening connects the mutually overlapping end sides of the first base body to one another, and / or the second opening connects the mutually overlapping end sides of the second base body to one another. In other words, at least one of the two openings can be a through opening.

[0024] A “basic body” may be understood to mean, for example, a cuboid body and / or a plastic body.

[0025] A "protrusion" may be understood as a rib-shaped or pin-shaped element, for example. For example, a first protrusion may be made of the same material as the first substrate and / or may be made as a single part with the first substrate, and / or a second protrusion may be made of the same material as the second substrate and / or may be made as a single part with the second substrate.

[0026] Among other functions, the retaining system enables the introduction of the first end portion and the activation of the spring ring to be performed in a single installation step. This simplifies the installation process.

[0027] A fifth aspect of the present invention relates to a battery module, which can be manufactured in a method according to an embodiment of the second aspect of the present invention described below or in another method. The battery module comprises: a first battery cell, the first battery cell comprising a first battery cell housing, the first battery cell housing having a cylindrical first end portion made of a conductive material; a second battery cell, the second battery cell comprising a second battery cell housing, the second battery cell housing having a cylindrical second end portion made of a conductive material; a contact element described above and below; a retaining system described above and below. The first battery cell housing is introduced into a first opening of a first retaining device so that the first end portion protrudes from the first opening. The second battery cell housing is introduced into a second opening of a second retaining device. The first end portion is received by a housing retainer. The spring ring is tensioned around the spring arm so that the spring arm is pressed against the (outer) peripheral surface of the first end portion received by the housing receiving portion. In addition, the second end portion contacts the side of the substrate facing away from the housing receiving portion.

[0028] Furthermore, the second end portion can be connected to the base plate in a materially bonded manner, for example welded, soldered or adhesively bonded.

[0029] Furthermore, the first loop end may be opposite the first protrusion and / or the second loop end may be opposite the second protrusion.

[0030] Features of the battery module may also be features of the method described above and below (and vice versa).

[0031] The embodiments of the present invention can be considered to be based on the ideas and knowledge described below. These embodiments should not be understood as limiting the present invention.

[0032] According to one embodiment, each ring end may comprise a bearing surface with a defined width in the direction of the central axis of the spring ring. Here, the ring ends that bear against each other may contact their bearing surfaces. One of the bearing surfaces that are in contact may be displaced from an initial position in the direction of the central axis beyond the end of the other bearing surface to achieve relaxation of the spring ring, i.e. to achieve activation of the spring ring. The width of the bearing surface may be, for example, at least 2 mm, at least 5 mm or at least 10 mm. The bearing surfaces may have the same or different widths. On the one hand, this may prevent the spring ring from being accidentally activated by slightly staggering the ring ends relative to each other; on the other hand, this may enable simple activation of the spring ring.

[0033] According to one embodiment, the widths of the abutment surfaces can differ from each other. Here, the wider abutment surface in the initial position can protrude from the narrower abutment surface on both sides in the direction of the central axis. For example, the wider abutment surface can be at least 2 times, at least 5 times or at least 10 times the width of the narrower abutment surface. For example, the widths can differ by at least 2 mm, at least 5 mm or at least 10 mm. In general, the smaller the force required for staggering the ring ends, the greater the deviation. If the ring ends are only slightly staggered from each other, it can be prevented that one abutment surface slides out of one end or the other end of the other abutment surface. Therefore, it can be prevented that the spring ring is accidentally activated.

[0034] According to one embodiment, the portion of the wider abutment surface which projects beyond the narrower abutment surface in the initial position can have the same width (in the direction of the central axis). In other words, the narrower abutment surface in the initial position can be arranged centrally relative to the wider abutment surface. Such a symmetrical arrangement of the abutment surfaces simplifies the installation of the spring ring, since it is then unimportant how the spring ring is placed on the spring arm.

[0035] It is also possible that one or each abutment surface in the starting position protrudes beyond the other abutment surface on one side in the direction of the central axis.

[0036] According to one embodiment, at least one ring end comprising a contact surface can be formed by a longitudinal portion of the spring ring that is bent at least twice. The longitudinal portion can be, for example, an elongated wire portion of the spring ring. Thus, one or more contact surfaces can be provided at low manufacturing costs.

[0037] According to one embodiment, the longitudinal portion may be bent at a first position along a first bending direction at a first bending angle, and at a second position along a second bending direction at a second bending angle. The second position may be located between the free end of the longitudinal portion and the first position. The abutment surface of the corresponding ring end may be formed by a straight portion of the longitudinal portion extending between the second position and the free end. The straight portion may be orthogonal with respect to its longitudinal direction, or may be inclined with respect to the circumferential direction of the spring ring.

[0038] According to one embodiment, the first bending angle and the second bending angle may be different from each other. For example, the bending angles may differ by at least 10%, at least 50% or at least 100%.

[0039] According to one embodiment, the first bending direction and the second bending direction may be different from each other.

[0040] According to one embodiment, the second bending angle may be greater than the first bending angle, in particular twice the first bending angle. For example, the first bending angle may be 90 degrees and / or the second bending angle may be 180 degrees.

[0041] According to one embodiment, the first bending direction may be opposite to the second bending direction.

[0042] According to one embodiment, one of the loop ends can be designed as a cup with a cup-shaped opening, and the other loop end can be introduced into the cup-shaped opening in a pre-tensioned state. The cup-shaped part thus serves as a closure to temporarily close the slit loop. A certain force may be required to open the closure. This prevents the spring ring from being accidentally activated. For example, the other loop end can be pulled out and / or pushed out of the cup-shaped opening manually and / or with the aid of a tool, so that the spring ring can relax.

[0043] According to one embodiment, the cup-shaped opening can have a defined depth and its diameter decreases as the depth increases. In other words, the cup-shaped piece can have a cross section on its inner side that is reduced in the circumferential direction of the spring ring, i.e., it is designed as a cone. As a result, the other ring end can be more easily introduced into the cup-shaped opening and / or more easily drawn out from the cup-shaped opening without excessive deformation of the spring ring, especially at its ring end. The depth of the cup-shaped opening can be, for example, between 1 mm and 10 mm. But the cup-shaped opening can also be deeper.

[0044] According to one embodiment, the material of the base plate and / or the spring arm can be copper and / or a copper alloy. In this way, compared with a conventional construction made of bronze, for example, this can improve the conductivity and solderability of the base plate and / or the spring arm.

[0045] According to one embodiment, the material of the spring ring can be different from the material of the base plate and / or the spring arm and / or can be steel, in particular spring steel. This achieves an improvement in the elasticity and / or strength of the spring ring.

[0046] According to one embodiment, the method of the present invention may also include: providing a second battery cell shell with a cylindrical second end portion made of a conductive material; providing a first holding device for holding the first battery cell shell, wherein the first holding device includes a first substrate, the first substrate having a first opening for introducing the first battery cell shell and a first protrusion, wherein the first protrusion extends from the end side of the first substrate having the first opening; providing a second holding device for holding the second battery cell shell, wherein the second holding device includes a second substrate, the second substrate having a second opening for introducing the second battery cell shell and a second protrusion, wherein the second protrusion extends from the end side of the second substrate having the second opening; placing the first battery cell The housing is introduced into the first opening so that the first end portion protrudes from the first opening; the second battery cell housing is introduced into the second opening; the holding device and the contact element are arranged so that the base plate is (at least partially) located between the first end portion and the second end portion (e.g. between the end side of the first end portion and the end side of the second end portion), the first end portion (e.g. with its end side) is opposite the housing receptacle, the first of the ring ends is opposite the first protrusion, and the second of the ring ends is opposite the second protrusion; the base body is assembled, wherein the first end portion is introduced into the housing receptacle and the spring ring is activated by pressing the first protrusion against the first ring end in a first force direction and the second protrusion against the second ring end in a second force direction opposite to the first force direction. By assembling the base body, the second end portion can be brought into contact with the base body, for example by pressing the second end portion against the side of the base body facing away from the housing receptacle. Additionally or alternatively, the second end portion can be connected to the base body in a materially bonded manner, in particular welded.

[0047] The material-bonded connection can be carried out before and / or after and / or during the assembly. If the second end part is connected to the base plate in a material-bonded manner before the assembly - for example before the second battery cell housing is introduced into the second opening - the advantage is that then no additional holding contact elements are necessary, which makes assembly easier. The second end part and the base plate can also be welded and / or glued to one another.

[0048] For example, the bottom plate can comprise, on its side facing away from the housing receptacle, a raised contact portion opposite the remaining surface of the base plate for contacting the second battery cell housing and / or an electrode of the second battery cell.

[0049] The projections should be designed such that the spring ring is activated only when the first end portion is (completely) introduced into the housing receptacle. The shapes of the projections can be identical or different from one another. For example, the projections can have different lengths, i.e. extend at different distances from the respective end side.

[0050] The cell housing should be seated firmly in its respective opening, so that when the base body is assembled, the cell housing does not rotate and / or shift relative to its respective opening, or only rotates and / or shifts to a negligible extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Embodiments of the present invention will be described below with reference to the accompanying drawings, which should not be construed as limiting the present invention.

[0052] Figure 1 A perspective view of a contact element with a preloaded spring washer according to a first embodiment of the invention is shown.

[0053] Figure 2 A perspective view of a contact element with an activated spring washer according to a first embodiment is shown.

[0054] Figure 3 A perspective view of a contact element with a preloaded spring washer according to a second embodiment of the invention is shown.

[0055] Figure 4 A perspective view of a contact element with an activated spring washer according to a second embodiment is shown.

[0056] Figure 5 A side view of a battery module according to an embodiment of the present invention is shown.

[0057] Figure 6 A perspective view of a first holding device of a holding system according to an embodiment of the invention is shown.

[0058] Figure 7 A perspective view of a second holding device of a holding system according to an embodiment of the invention is shown.

[0059] The drawings are only schematic and not drawn to scale. If the same reference numerals are used in different drawings, these reference numerals denote identical or functionally identical features. DETAILED DESCRIPTION

[0060] Figure 1 The contact element 1 is shown for making electrically conductive contact with the cylindrical end section 3 of the cell housing 5 of a battery cell 7, which is a round battery here (see Figure 5 and Figure 6 ), for example, a lithium-ion round battery for a battery module of an electric vehicle in the form of a car, truck, bus or motorcycle. The end portion 3 can be, for example, a conductive cover for closing the battery cell housing 5. The cover can serve as a first electrode of the battery cell 7.

[0061] In this example, the contact element 1 comprises a disc-shaped base plate 9, from which a plurality of - in this case six - spring arms 11 extend in a star shape from the outer contour of the base plate 9, i.e. extend radially outward. The spring arms 11 are evenly distributed along the circumferential direction of the base plate 9. The free ends of the spring arms 11 are respectively bent in the same direction at the same bending angle, which is about 90° in this case. Therefore, each spring arm 11 is angled. The bent ends of the spring arms 11 jointly define the boundaries of a housing receiving portion 13, into which the end portion 3 can be introduced, so that the bent ends of the spring arms 11 are opposite to different positions of the outer peripheral surface 14 of the end portion 3 introduced into the housing receiving portion 13.

[0062] In the unloaded state of the spring arm 11, the diameter of the housing receiving portion 13 may be larger, for example at least 10% larger, than the diameter of the end portion 3. Alternatively, the diameter of the housing receiving portion 13 may be slightly smaller than the diameter of the end portion 3, so that a certain force may be required to introduce the end portion 3 into the housing receiving portion 13.

[0063] The base plate 9 and the spring arms 11 can be produced, for example, from the same metal sheet by stamping and / or forming.

[0064] The bent end portion of the spring arm 11 is surrounded by a spring ring 15, which has the form of a slotted ring with a first ring end 17a and a second ring end 17b. In the simplest case, the spring ring 15 can be formed by a correspondingly bent wire segment as is the case here.

[0065] Each bent end portion of the spring arm 11 may comprise an elongated recess for receiving a longitudinal portion of the spring ring 15, wherein each recess receives a different longitudinal portion of the spring ring 15. This may, for example, prevent the spring ring 15, which is tensioned around the spring arm 11, from falling off or popping off the spring arm 11 when the contact element 1 is mounted.

[0066] Figure 1 The spring ring 15 in the pre-tensioned state is shown. Here, the ring ends 17a, 17b abut against each other in the circumferential direction of the spring ring 15, so that the spring ring 15 is prevented from loosening.

[0067] Figure 2 The spring ring 15 is shown in an activated state, i.e., in an at least partially relaxed state. Compared to the preloaded state, the ring ends 17a, 17b are laterally offset from one another, i.e., in the direction of the center axis M of the spring ring 15. In addition, the ring ends 17a, 17b overlap in the circumferential direction of the spring ring 15.

[0068] The spring ring 15 is shaped so that, by activating the spring ring 15, the spring arms 11 are pressed radially inwardly with a certain spring force (i.e., with a certain pressing force) against the outer circumference 14 of the end portion 3 received by the housing receptacle 13. This achieves a reliable contact with the battery cell housing 5 (see Figure 5 ). In the preloaded state, however, the diameter of the spring ring 15 can be so large that the spring ring 15 does not press against the spring arm 11 or presses against the spring arm 11 with a significantly lower spring force than in the activated state. This has the effect that the end section 3 can be positioned with greater play in the housing receptacle 13 without overloading the spring arm 11 as a result.

[0069] As in Figure 1 and Figure 2 As shown in , one of the two ring ends 17a, 17b, here the second ring end 17b, can be bent into an S-shape (also referred to as an S-bend). To this end, for example, the longitudinal portion of the spring ring 15 can be bent 90° in a first bending direction at a first position S1, and can be bent 180° in a second bending direction opposite to the first bending direction at a second position S2 located between the first position S1 and the free end of the longitudinal portion. The straight portion of the longitudinal portion extending between the second position S2 and the free end can be used as a contact surface for the first ring end (here the non-bent ring end 17a). As shown in Figure 1 It can be seen that in the preloaded state, the first ring end 17a can contact the abutment surface 19a with its end surface 19b (the end surface 19b thus serves as a second abutment surface 19b for the second ring end 17b).

[0070] The abutment surfaces 19a, 19b may have different widths when viewed in the direction of the central axis M. For example, the wider abutment surface 19a may be at least twice as wide as the narrower abutment surface 19b, or at least four times as wide.

[0071] As in Figure 1 As can be seen in FIG. 1 , the wider abutment surface 19a may protrude beyond the narrower abutment surface 19b on both sides in the direction of the central axis M in the initial position. The portions of the wider abutment surface 19a protruding beyond the narrower abutment surface 19b may have substantially the same width.

[0072] The spring ring 15 can be activated by moving one of the abutment surfaces 19a, 19b from the initial position to the outside of the other abutment surface 19a or 19b, so that the ring ends 17a, 17b no longer interfere with each other in the circumferential direction of the spring ring 15, and the spring ring 15 can relax, i.e., can shrink (see Figure 2 ).

[0073] Figure 3 and Figure 4An alternative embodiment of a contact element 1 is shown, in which the two ring ends 17a, 17b are connected to one another in a form-fitting and force-fitting manner via an unlockable closure device in the preloaded state. For this purpose, the second ring end 17b comprises a cup 21 with a conical cup-shaped opening 23, the cross section of which tapers with increasing depth. The first ring end 17a is introduced into the cup-shaped opening 23 in the preloaded state (see Figure 3 ). However, in the activated state, the first ring end 17a is located outside the cup 21 (see Figure 4 The cup-shaped opening 23 has a certain depth, so that the first ring end 17a introduced therein can be drawn out from the cup-shaped opening 23 only by exerting a certain amount of force, for example, by laterally offsetting the first ring ends 17a, 17b in the direction of the central axis M with the aid of a suitable tool (see Figure 5 , Figure 6 and Figure 7 ).

[0074] When manufacturing the battery cell 7, the end portion 3 can first be introduced into the housing receptacle 13 around which the prestressed spring ring 15 is tensioned. The spring ring 15 can then be activated by offsetting the ring ends 17a, 17b relative to each other in the direction of the center axis M so that the ring ends 17a, 17b no longer abut against each other. The activated spring ring 15 tensions the spring arm 11 with a certain spring force, by which the spring arm 11 is pressed against the outer circumference 14 of the end portion 3 introduced into the housing receptacle 13 with a certain pressing force.

[0075] Figure 5 A battery module 24 is shown with a battery cell 7 as a first battery cell 7 and a second battery cell 25 which comprises a second battery cell housing 27 with a cylindrical second end portion 29. The second battery cell 25 can be designed in the same or similar manner as the first battery cell 7 as a round cell.

[0076] At least the end sections 3, 29 can be made of a metallic material, so that the battery cells 7, 25 can be electrically conductively contacted via their respective end sections 3 and 29. The battery cell housing 5, 27 can also be made completely of a metallic material.

[0077] The battery module 24 can be produced in the following manner with the aid of the holding system 31 . The holding system 31 can be a component of the (finished) battery module 24 .

[0078] The holding system 31 comprises a first holding device 33a for holding the first battery cell housing 5 (see Figure 6 ) and a second holding device 33b operable separately from the first holding device 33a (see Figure 7) for holding the second battery cell housing 27. The holding devices 33a, 33b may also be referred to as cell frames.

[0079] Each holding device 33a, 33b comprises a base body 35a or 35b with an opening 37a or 37b for introducing at least one part of the respective battery cell housing 5 or 27, here a continuous opening that connects the opposite end sides of the respective base body 35a or 35b to one another. A first projection 39a protrudes from the end face of the first base body 35a where the first opening 37a ends. A second projection 39b protrudes from the end face of the first base body 35b where the second opening 37b ends.

[0080] In this method, the battery cell housing 5, 27 is first introduced into the corresponding openings 37a and 37b. Here, the first battery cell housing 5 is introduced into the first opening 37a so that the first end portion 3 protrudes from the first opening 37a on the end side of the first base body 35a having the first protrusion 39a. The second battery cell housing 27 can be introduced into the second opening 37b so that the end side of the second end portion 29 is substantially flush with the end face of the second base body 35b having the protrusion 39b, or only protrudes slightly, for example, less than 10 mm or less than 5 mm.

[0081] The retaining devices 33a, 33b and the contact element 1 are then positioned relative to each other so that the shell receiving portion 13 is opposite to the end side of the first end portion 3, the side of the substrate 9 facing away from the shell receiving portion 13 is opposite to the end side of the second end portion 29, the first protrusion 39a is opposite to the first ring end 17a, and the second protrusion 39b is opposite to the second ring end 17b, and here is opposite to the part of the second ring end 17b adjacent to the cup-shaped member 21.

[0082] As in Figure 5 As can be seen in the figure, the length of the first protrusion 39a can be significantly different from the length of the second protrusion 39b, for example, the length of the first protrusion 39a can be significantly shorter than the length of the second protrusion 39b. In this example, the length of the first protrusion 39a is only half of the length of the second protrusion 39b.

[0083] The holding devices 33a, 33b are then moved toward each other along the mounting axis, which corresponds here to the center axis M, until the end section 3 is completely introduced into the housing receptacle 13 and the second end section 29 contacts the base plate 9 with its end side, for example with a defined contact pressure against the base plate 9. In this process, the ring ends 17a, 17b are offset relative to each other in the direction of the center axis M by the projections 39a, 39b moving toward each other until the first ring end 17a springs away from the cup 21 and the spring ring 15 snaps into place, i.e. is activated.

[0084] Before the holding devices 33a, 33b are combined, in particular before the second battery cell housing 27 is introduced into the opening 37b, the second end portion 29 and the base plate 9 can be welded to one another, for example by laser welding. This simplifies the further installation of the battery module 24.

[0085] The battery module 24 may also include two or more components, each of which is constructed from a holding system 31, two battery cells 7, 25 and a contact element 1. In this case, the battery cells and / or contact elements of different components can be connected to each other in an electrically conductive manner, for example, to connect the battery cells of different components to each other in series and / or in parallel.

[0086] Depending on the embodiment, the above method steps may also be implemented in different orders.

[0087] Finally, it should be noted that the terms "comprises", "comprising", "including", "having" etc. do not exclude other elements or steps, and that indefinite articles such as "a" or "an" do not exclude a plurality. It should also be noted that features or steps described with reference to one of the above embodiments may also be used in combination with features or steps described with reference to other above embodiments. The reference signs in the claims shall not be construed as limiting the invention.

[0088] Reference numerals list

[0089] 1Contact element

[0090] 3 First end portion

[0091] 5First battery cell housing

[0092] 7First battery unit

[0093] 9 substrates

[0094] 11 Spring Arm

[0095] 13 Shell receiving portion

[0096] 14 weeks

[0097] 15 Spring ring

[0098] 17a First ring end

[0099] 17b Second ring end

[0100] 19a first abutment surface

[0101] 19b Second abutment surface

[0102] 21 cup-shaped pieces

[0103] 23 cup-shaped opening

[0104] 24 battery modules

[0105] 25 Second battery unit

[0106] 27 Second battery unit housing

[0107] 29 second end portion

[0108] 31. Keep the system

[0109] 33a First holding device

[0110] 33b Second holding device

[0111] 35a First substrate

[0112] 35b Second substrate

[0113] 37a First opening

[0114] 37b Second opening

[0115] 39a First protrusion

[0116] 39b Second protrusion

[0117] M Center axis

[0118] S1 first position

[0119] S2 Second Position

Claims

1. A contact element (1) for electrically conductively contacting a battery cell housing (5), wherein: The battery cell housing (5) comprises a cylindrical end portion (3) made of an electrically conductive material, wherein the contact element (1) comprises: a substrate (9) made of a conductive material; A plurality of spring arms (11) made of a conductive material, wherein the spring arms (11) extend at different positions of the base plate (9) and together define a boundary of a housing receiving portion (13) for receiving the battery cell housing (5); A spring ring (15) is designed to be tensioned around the spring arm (11) so that the spring arm is pressed against the circumferential surface (14) of the end portion (3) received by the housing receiving portion (13), wherein the spring ring (15) is a slotted ring with two ring ends (17a, 17b), and the spring ring has a larger diameter in a pre-tensioned state than in a relaxed state, wherein the ring ends (17a, 17b) abut against each other in the circumferential direction of the spring ring (15) in the pre-tensioned state to prevent the spring ring (15) from undesirably loosening.

2. The contact element (1) according to claim 1, in, Each of the ring ends (17a, 17b) comprises a contact surface (19a, 19b) having a defined width in the direction of the central axis (M) of the spring ring (15), and the ring ends (17a, 17b) contacting each other on their contact surfaces (19a, 19b); One of the contacting abutment surfaces (19a, 19b) can be moved from an initial position to outside the end of the other abutment surface (19a, 19b) along the direction of the central axis (M), so that the spring ring (15) is relaxed.

3. The contact element (1) according to claim 2, in, The widths of the abutment surfaces (19a, 19b) are different from each other; Among the abutment surfaces (19a, 19b) in the initial position, the wider abutment surface (19a) protrudes beyond the narrower abutment surface (19b) on both sides along the direction of the central axis (M).

4. The contact element (1) according to claim 3, wherein: The portion of the wider contact surface (19a) that projects beyond the narrower contact surface (19b) in the initial position has the same width.

5. The contact element (1) according to any one of claims 2 to 4, wherein: At least one of the ring ends (17a, 17b) comprising the abutment surface (19a, 19b) is formed by a longitudinal portion of the spring ring (15) that is bent at least twice.

6. The contact element (1) according to claim 5, in, The longitudinal portion is bent at a first bending angle along a first bending direction at a first position (S1), and is bent at a second bending angle along a second bending direction at a second position (S2); wherein the second position (S2) is located between the free end of the longitudinal portion and the first position (S1); Therein, the abutment surface (19a, 19b) of the respective loop end (17a, 17b) is formed by a straight portion of the longitudinal portion extending between the second position (S2) and the free end.

7. The contact element (1) according to claim 6, in, The first bending angle and the second bending angle are different from each other; and / or wherein the first bending direction and the second bending direction are different from each other; and / or Wherein, the second bending angle is greater than the first bending angle, in particular, twice the first bending angle; and / or Wherein, the first bending direction is opposite to the second bending direction.

8. The contact element (1) according to claim 1, wherein: One of the ring ends (17a, 17b) is designed as a cup (21) with a cup-shaped opening (23), while the other ring end (17a) is introduced into the cup-shaped opening (23) in a pre-tensioned state.

9. The contact element (1) according to claim 8, wherein: The cup-shaped opening (23) has a defined depth, and the diameter of the cup-shaped opening decreases as the depth increases.

10. The contact element (1) according to any one of the preceding claims, in, The material of the substrate (9) and / or the spring arm (11) is copper and / or a copper alloy; and / or The material of the spring ring (15) is different from the material of the base plate (9) and / or the spring arm (11) and / or is steel, in particular spring steel.

11. A method for electrically conductively contacting at least one battery cell housing (5, 27), the method comprising: Providing a first battery cell housing (5) having a cylindrical first end portion (3) made of an electrically conductive material; A contact element (1) according to any one of claims 1 to 10 is provided, wherein a preloaded spring ring (15) surrounds a spring arm (11) defining a housing receptacle (13); introducing the first end portion (3) into the housing receiving portion (13); The spring ring (15) is activated by shifting the ring ends (17a, 17b) relative to each other in the direction of the central axis (M) of the spring ring (15) until the ring ends (17a, 17b) no longer abut against each other in the circumferential direction of the spring ring (15), so that the spring ring (15) can relax, wherein the activated spring ring (15) is tensioned around the spring arm (11), so that the spring arm is pressed against the circumferential surface (14) of the first end portion (3) received by the housing receptacle (13).

12. The method according to claim 11, further comprising: providing a second battery cell housing (27) having a cylindrical second end portion (29) made of an electrically conductive material; providing a first holding device (33a) for holding the first battery cell housing (5), wherein the first holding device (33a) comprises a first base body (35a), the first base body (35a) having a first opening (37a) for introducing the first battery cell housing (5) and a first projection (39a), wherein the first projection (39a) projects from the end side of the first base body (35a) having the first opening (37a); providing a second holding device (33b) for holding the second battery cell housing (27), wherein the second holding device (33b) comprises a second base body (35b), the second base body (35b) having a second opening (37b) for introducing the second battery cell housing (27) and a second projection (39b), wherein the second projection (39b) projects from the end side of the second base body (35b) having the second opening (37b); introducing the first battery cell housing (5) into the first opening (37a) so that the first end portion (3) protrudes from the first opening (37a); introducing the second battery cell housing (27) into the second opening (37b); The holding device (33a, 33b) and the contact element (1) are arranged such that: The base plate (9) is located between the first end portion (3) and the second end portion (29), The first end portion (3) is opposite to the housing receiving portion (13), The first ring end (17a) of the ring ends (17a, 17b) is opposite to the first protrusion (39a), The second ring end (17b) of the ring ends (17a, 17b) is opposite to the second protrusion (39b), The base bodies (35a, 35b) are combined, wherein the first end portion (3) is introduced into the housing receptacle (13) and the spring ring (15) is activated in such a way that the first projection (39a) is pressed against the first ring end (17a) in a first force direction and the second projection (39b) is pressed against the second ring end (17b) in a second force direction opposite to the first force direction; The second end portion (29) is brought into contact with the base plate (9) by combining the base bodies (35a, 35b) and / or connecting them to the base plate (9) in a materially bonded manner, in particular by welding.

13. A battery cell (7), in particular a battery cell (7) manufactured using the method according to claim 11, wherein: The battery unit (7) comprises: A battery cell housing (5) having a cylindrical end portion (3) made of an electrically conductive material; A contact element (1) according to any one of claims 1 to 10, wherein the end portion (3) is received by a housing receptacle (13), and a spring ring (15) is tensioned around a spring arm (11) so that the spring arm is pressed against a circumferential surface (14) of the end portion (3) received by the housing receptacle (13).

14. A holding system (31) for performing the method according to claim 12, wherein: The retaining system (31) comprises: a first holding device (33a) for holding a first battery cell housing (5), wherein the first holding device (33a) comprises a first base body (35a), the first base body (35a) having a first opening (37a) for introducing the first battery cell housing (5) and a first projection (39a), wherein the first projection (39a) projects from the end side of the first base body (35a) having the first opening (37a); A second holding device (33b) for holding a second battery cell housing (27), wherein the second holding device (33b) comprises a second base body (35b), the second base body (35b) having a second opening (37b) for introducing the second battery cell housing (27) and a second protrusion (39b), wherein the second protrusion (39b) protrudes from the end side of the second base body (35b) having the second opening (37b).

15. A battery module (24), in particular a battery module (24) produced using the method according to claim 12, wherein: The battery module (24) comprises: A first battery cell (7) comprising a first battery cell housing (5) having a cylindrical first end portion (3) made of an electrically conductive material; a second battery cell (25), the second battery cell comprising a second battery cell housing (25) having a cylindrical second end portion (29) made of an electrically conductive material; The contact element (1) according to any one of claims 1 to 10; A retaining system (31) according to claim 14; in, The first battery cell housing (5) is introduced into the first opening (37a) so that the first end portion (3) protrudes from the first opening (37a), and the second battery cell housing (27) is introduced into the second opening (37b); wherein the first end portion (3) is received by the housing receiving portion (13), and the spring ring (15) is tensioned around the spring arm (11), so that the spring arm (11) is pressed against the circumferential surface (14) of the first end portion (3) received by the housing receiving portion (13); The second end portion (29) contacts the side of the base plate (9) facing away from the housing receiving portion (13).

Images