Arrangement of a cell terminal on a battery cell housing and a method for connecting a cell terminal to a battery cell housing

Abstract

Arrangement of a cell terminal on a battery cell housing (10), wherein the cell terminal (12) has a contact surface (16) which is electrically conductively connected to a conductor (36) of a battery cell arranged in the battery cell housing (10), characterized in that the contact surface (16) is firmly connected to a carrier element (18), wherein at least one clip element (20) is formed on the carrier element (18), wherein the contact surface (16) is directly or indirectly connected to the battery cell housing (10) by means of the clip element (20), wherein the contact surface (16) is overmolded by the carrier element (18) or the contact surface (16) is thermally pressed into the carrier element (18), wherein the carrier element (18) is made of plastic.

Description

[0001] The invention relates to an arrangement of a cell terminal on a battery cell housing and a method for connecting a cell terminal to a battery cell housing, in particular to a cover element of a battery cell housing.

[0002] The invention relates in particular to prismatic battery cell housings for battery cells with a cell voltage of 1 V to 10 V, preferably with 2 V to 8 V, and particularly preferably with 2.5 V to 5 V. Such battery cell housings are used in particular for the production of battery modules for vehicles, whereby in practice several modules are often connected together to form a battery system. Alternatively, it is possible to install all battery cells or battery cell housings directly into a battery box or to attach them directly to the underbody of a motor vehicle.

[0003] In practice, the voltage of vehicle battery systems is typically at least 48 V, particularly in a range between 48 V and 800 V, preferably between 200 V and 1,000 V, and most preferably between 400 V and 800 V. Such battery systems are also referred to as high-voltage battery systems. These battery systems can extend over an area of ​​1.5 m x 2.5 m.

[0004] The aforementioned battery cell casings are frequently used in practice for lithium-ion battery cells, including iron-phosphate and sodium-based battery cells, and are particularly suitable for these battery types. The battery cell casings are suitable for liquid-based, gel-based, and solid-state battery cells. Currently, lithium-ion battery cells are the most commonly used in practice.

[0005] From DE 39 02 632 A1, a battery with a terminal bushing for lead-acid batteries is known, in which a cylindrical, solid terminal end piece is arranged. In one embodiment, the terminal bushing is formed by a cup-shaped wall and an intermediate piece, which in another embodiment is intended to be snapped into a battery cover. A separate contact surface connected to a support element is not disclosed.

[0006] DE 20 2007 010 980 U1 discloses a terminal bushing comprising a one-piece ring body and several detents formed on the ring body. The detents are intended to connect the terminal bushing to the cover of a battery housing (not shown). A cell terminal, a battery housing, a contact surface, or a conductor as defined in the invention are neither shown nor described. The terminal bushing described in DE 20 2007 010 980 U1 is also intended for lead-acid batteries with a solid, cylindrical terminal end.

[0007] From US 2014 / 0087217 A1, a battery cell with a metallic battery cell casing is known, which is hermetically sealed by means of a lid element in a known manner, in particular by means of a weld. A spring element, referred to as a "click spring area," is arranged in the lid element. When a predetermined pressure inside the battery cell is exceeded, this spring element switches from a first, inwardly convex state to a second, outwardly convex state. During the switch to the second state, an electrical connection is established between the lid element and one of the current-carrying collectors in order to deactivate the corresponding battery cell by short-circuiting. Apart from the short-circuiting function described above, the spring element is independent of the collectors. The spring element is arranged centrally between the two collectors and spaced apart from each of them.The lid element is formed from a multitude of individual elements. In particular, the lid element features a separate filling opening and a separate bursting membrane.

[0008] In established practices, complex welding processes are typically used to integrate cell terminals into battery cell housings. These processes require a complex terminal assembly made of metal and plastic, to which the weld connection to the battery cell housing can be made. In addition to this complex joining process, this approach also necessitates a battery cell housing with an additional rupture membrane and a separate filling port. The separate filling port represents an additional weak point in the battery cell housing. The additional rupture membrane is usually welded in place, which can introduce further defects into the battery cell housing. Furthermore, the weight of the battery cell housing and the manufacturing time increase due to the additional component.

[0009] The invention is based on the objective of providing an arrangement of a cell terminal on a battery cell housing and a method for connecting a cell terminal to a battery cell housing, which simplify the manufacture of battery cells.

[0010] The problem is solved according to the invention by the features of the independent claims. Further practical embodiments and advantages of the invention are described in connection with the dependent claims.

[0011] In an arrangement according to the invention of a cell terminal on a battery cell housing, the cell terminal has a contact surface which is electrically connected to a conductor of a battery cell arranged in the battery cell housing. The contact surface is connected to the battery cell housing directly or indirectly by means of a clip element. In particular, a plate-like element made of a metallic material, especially a sheet, can serve as the contact surface. Preferably, the contact surface is a plate or sheet made of aluminum or copper. It can also be an aluminum sheet or plate coated with copper on one or both sides. The arrangement according to the invention makes it possible to connect a cell terminal to the battery cell housing in a particularly simple manner and without a welding process.This simplifies the production of battery cells, particularly if one or more of the features described below are also implemented in the arrangement or if the inventive method is carried out. A key element of the agreement is that the at least one clip element creates a clip connection that allows for a quick yet sufficiently secure connection, which can still be reliably established even after the battery cell housing has been filled with an electrolyte. This can result in further advantages, which will be discussed in more detail below.

[0012] In the arrangement according to the invention, the contact surface is firmly connected to a support element, wherein at least one clip element is formed on the support element. The support element can be formed in one or more parts. Preferably, the support element is formed in one part, because then the support element can be manufactured particularly simply and cost-effectively.

[0013] In a practical embodiment of an arrangement according to the invention, the clip element has at least one outer section, at least one penetration section, and at least one inner section, which are formed on the contact surface itself and / or on at least one further element connected to the contact surface. The terms "outer" and "inner" refer to the battery cell housing; that is, the outer section is outside the battery cell housing in the final assembly state, and the "inner section" is inside the battery cell housing in the final assembly state. In other words, the at least one clip element is preferably configured, at least partially, such that an outer section, a penetration section, and an inner section are visible in the final assembly state. These are preferably C-shaped in cross-section, in particular such that they encompass an outer wall of the battery cell housing.

[0014] It is further preferred, particularly from aspects of the tightness of the arrangement according to the invention, if the contact surface is arranged to completely enclose the support element.

[0015] In the arrangement according to the invention, the support element is made of plastic: it can be produced easily and cost-effectively, especially in large quantities, using the plastic injection molding process.

[0016] In the arrangement according to the invention, the contact surface is overmolded by the support element, according to a first embodiment. The support element is manufactured, in particular, using plastic injection molding. This is because, in this case, the contact surface and the support element are fixed to each other in a desired relative orientation directly during the manufacturing of the support element. This eliminates assembly work and largely prevents assembly errors.

[0017] Alternatively, in a second variant of an arrangement according to the invention, the contact surface is thermally pressed into the support element.

[0018] In another practical embodiment of an arrangement according to the invention, a sealing element is arranged between the outer section and the inner section. In this regard, particular reference is made to a sealing element made of a silicone material and / or an elastomer material. For manufacturing and assembly reasons, it is preferred if the sealing element is directly injection-molded onto the outer section, the penetration section, and / or the inner section. It is further preferred if the sealing element is a fully circumferential sealing element having a closed circumferential contour.

[0019] If a recess is provided for the arrangement of the sealing element, in particular a circumferential groove, the sealing element is particularly securely protected against displacement.

[0020] For creating the clip connection, it is preferred if a penetration section is designed such that it can be deflected elastically in a direction transverse to the assembly direction, and an insertion ramp is formed on the inner section such that the penetration section is deflected elastically by means of the insertion ramp during the creation of the clip connection. In this case, assembly is particularly simple and reliable, especially if two or more insertion ramps are provided and arranged such that the clip connection can be created by applying a simple compressive force in the assembly direction.

[0021] The manufacture of an arrangement according to the invention is particularly simplified if the contact surface is arranged in a battery cell housing opening, which is additionally designed as a burst opening and / or as a filling opening.

[0022] A battery cell housing opening is designed as a burst opening, in particular, if, after the battery cell housing is closed and the battery cell is put into operation, the battery cell housing opening, with its contact surface, is the first opening to be released by material failure as the pressure inside the battery cell housing increases. For this purpose, the clip connection can be designed such that at least one locking contour of the at least one clip element breaks off when a predetermined pressure is exceeded. Such a locking contour can be provided, in particular, on an inner section of the clip element.

[0023] A battery cell housing opening is designed as a filling opening, in particular if this opening is used for filling the battery cell housing with electrolyte or can at least be used in a process-reliable manner.

[0024] For the sake of completeness, it should be noted that preferably two battery cell housing openings are provided, each for a cell terminal. These can be located on the same side of the battery cell housing or on two different sides. Preferably, they are located on opposite sides of the battery cell housing because this allows for particularly efficient use of the battery cell housing volume (higher volume utilization).

[0025] The invention also relates to a method for connecting a cell terminal to a battery cell housing, wherein the cell terminal has a contact surface, wherein the contact surface is firmly connected to a carrier element, wherein at least one clip element is formed on the carrier element, and wherein the contact surface is overmolded by a carrier element or the contact surface is thermally pressed into the carrier element, wherein the carrier element is made of plastic, and wherein the contact surface is first electrically connected to a conductor of a battery cell arranged in the battery cell housing, and wherein the contact surface is then connected directly or indirectly to the battery cell housing by means of a clip connection in such a way that a cell terminal opening formed in the battery cell housing is closed.The connection between the current collector and the contact surface is preferably made by material bonding, in particular by welding or soldering.

[0026] In a practical embodiment of the method according to the invention, an electrolyte is filled into the battery cell housing through the cell terminal opening before the clip connection is made. Reference is hereby made again to the advantages already described above in connection with the arrangement according to the invention.

[0027] Further practical embodiments of the invention are described below in connection with the drawings. They show: Fig. 1 A battery cell housing with a cell terminal, which is intended for arrangement in a battery cell housing opening, before the battery cell housing opening is closed, in a sectional view, Fig. 2 the battery casing Fig. 1 after closing the battery cell housing opening in the same sectional view as in Fig. 1, Fig. 3 an isometric representation of only the cell terminal, which is essentially formed from a support element and a contact surface Fig. 4 the battery cell casing from the Fig. 1 and Fig. 2 in a first functional state during operation of the battery cell, Fig. 5 the battery cell casing from the Fig. 1 and Fig. 2 in a second functional state during operation of the battery cell and Fig. 6 the battery cell casing from the Fig. 1 and Fig. 2 in a potential third operating state during operation of the battery cell.

[0028] Fig. Figure 1 shows a battery cell housing 10 with a cell terminal 12, which is designed for placement in a battery cell housing opening 14, before the battery cell housing opening 14 is closed. The cell terminal 12 has a contact surface 16, which in the illustrated embodiment consists of an aluminum sheet. Alternatively, the contact surface 16 can also be made of another electrically conductive material or a suitable composite material. In the illustrated embodiment, the contact surface 16 has a rectangular shape and, as can be seen from a view of the Fig. 1 and Fig. 3 results in a fixed connection to a carrier element 18. The carrier element 18 is made of plastic. The contact surface 16 was placed in a plastic injection mold and overmolded with plastic during the production of the carrier element 18.

[0029] It should be noted that the contact surface 16 can alternatively have a round, oval, or other basic shape. Furthermore, the corners can also be rounded.

[0030] The battery cell housing 10 is preferably made of a plastic, in particular a fiber-reinforced plastic, of steel, or of aluminum. In practice, the battery cell housing 10 is frequently made of a metallic material, in particular of aluminum. It is usually manufactured as a container open at one or both ends and closed by means of one or two lids (usually welded). It is advantageous to provide the battery cell housing opening(s) 14 in one or both lids and then close them by means of the respective cell terminal 12.

[0031] The size of the contact area 16 is preferably between 10 mm x 10 mm and 50 mm x 50 mm, in particular between 10 mm x 30 mm and 20 mm x 50 mm.

[0032] As in Fig. As can be seen in Figure 3, two clip elements 20 are formed on the carrier element 18. Alternatively, more clip elements 20 may be formed (not shown).

[0033] The Fig. 1, Fig. 2, Fig. 4, Fig. 5 and Fig. Figure 6 each shows a cross-sectional view through the clip elements 20. In particular, in the Fig. 1 and Fig. Figure 2 clearly shows that each of the two clip elements 20 has an outer section 22, a penetration section 24 and an inner section 26. In the embodiment shown, these are formed integrally on the carrier element 18.

[0034] A sealing element 28 is also arranged in the transition area between the outer section 22 and the penetration section 24. In the embodiment shown, the sealing element 28 is a circumferential sealing ring 30 with an oval cross-section.

[0035] On the inner sections 26, an insertion ramp 32 is formed such that during the manufacture of the clip connection, the penetration section 24 is deflected spring-elastically by means of the insertion ramp 32.

[0036] In the Fig. 1, Fig. 2, Fig. 4, Fig. 5 and Fig. Figure 6 also schematically shows a cell stack 34 of a battery cell, from which a conductor 36 extends in the representation of the Fig. 1 extends outwards through the battery cell housing opening 14. In this state, the arrester 36 can be easily connected to the contact surface 16, in particular by welding the arrester 36 to the contact surface 16 on the inside. This can be done in particular by means of a weld point 38, as shown in Fig. 1 indicated or alternatively via two or more welding points 38 (not shown).

[0037] Alternatively to the representation in the Fig. 1, Fig. 2, Fig. 4, Fig. 5 and Fig. 6. An additional contact plate can also be attached and extended to the outside (not shown). In this case, there would be no direct connection between the surge arrester 36 and the contact surface 16.

[0038] After the current collector 36 has been electrically connected to the contact surface 16, the battery housing opening 14 can be used to fill the battery cell housing 10 with electrolyte. The carrier element 18 can then be oriented with the contact surface 16 in the assembly direction as indicated by arrow M. Fig. 2 are pressed into the battery cell housing opening 14, creating a clip connection, as shown in Fig. 2 shown.

[0039] The Fig. 4, Fig. 5 and Fig. Figure 6 shows that the cell terminal 12 in the illustrated embodiment is also designed as a bursting element. If, as in Fig. As indicated by the arrows p in Figure 4, during operation of the battery cell 34, the internal pressure in the battery cell housing 10 increases. In the illustrated embodiment, the cell terminal 12 is designed such that the battery cell housing opening 14 is released by at least partial destruction of the support element 18. In the illustrated embodiment, the inner sections 26 of the support element 18 tear off, causing the pressure p to force the support element 18 out of the battery cell housing opening 14. The connection between the contact surface 16 and the drain 36, in conjunction with the support element 18, can further be designed such that the drain 36 tears off the contact surface 16. This design is optional and in Fig. 6 shown.

[0040] The battery cell housings 10 typically have dimensions ranging from 50 mm x 50 mm x 50 mm to 300 mm x 300 mm x 300 mm. More commonly, the size is between 300 mm x 150 mm x 50 mm and 200 mm x 100 mm x 10 mm.

[0041] The features of the invention disclosed in the present description, the drawings, and the claims can be essential for realizing the invention in its various embodiments, both individually and in any combination. The invention can be varied within the scope of the claims and taking into account the knowledge of the person skilled in the art. Reference symbol list 10 battery cell casings 12 cell terminal 14 Battery cell casing opening 16 contact area 18 support element 20 clip elements 22 Exterior section 24 Penetration section 26 Interior section 28 Sealing element 30 sealing ring 32 Inset ramp 34 cell stacks 36 drains 38 welding points

Claims

[1] Arrangement of a cell terminal on a battery cell housing (10), wherein the cell terminal (12) has a contact surface (16) which is electrically connected to a conductor (36) of a battery cell arranged in the battery cell housing (10), characterized by , that the contact surface (16) is firmly connected to a carrier element (18), wherein at least one clip element (20) is formed on the carrier element (18), wherein the contact surface (16) is directly or indirectly connected to the battery cell housing (10) by means of the clip element (20), wherein the contact surface (16) is overmolded by the carrier element (18) or the contact surface (16) is thermally pressed into the carrier element (18), wherein the carrier element (18) is made of plastic. [2] Arrangement according to the foregoing claim, characterized by, that the at least one clip element (20) has at least one outer section (22), at least one penetration section (24) and at least one inner section (26), which are formed on the contact surface (16) itself and / or on at least one further element connected to the contact surface (16). [3] Arrangement according to one of the two preceding claims, characterized by , that a sealing element (28) is arranged between the outer section (22) and the inner section (26). [4] Arrangement according to one of the three preceding claims, characterized by, that at least one penetration section (24) is designed such that it can be deflected in a direction transverse to the assembly direction in a spring-elastic manner and that an insertion ramp (32) is formed on the inner section (26) such that during the production of a clip connection with the at least one clip element (20) the penetration section (24) is deflected in a spring-elastic manner by means of the insertion ramp (32). [5] Arrangement according to any of the foregoing claims, characterized by , that the contact surface (16) is arranged in a battery cell housing opening (14) which is additionally designed as a burst opening and / or as a filling opening. [6] Method for connecting a cell terminal (12) to a battery cell housing (10), wherein the cell terminal (12) has a contact surface (16), wherein the contact surface (16) is firmly connected to a carrier element (18), wherein at least one clip element (20) is formed on the carrier element (18), and wherein the contact surface (16) is overmolded by a carrier element (18) or the contact surface (16) is thermally pressed into the carrier element (18), wherein the carrier element (18) is made of plastic, and wherein the contact surface (16) is first electrically connected to a conductor (36) of a battery cell arranged in the battery cell housing (10), and wherein the contact surface (16) is then connected directly or indirectly to the battery cell housing (10) by means of a clip connection in such a way that a cell terminal opening formed in the battery cell housing (10) is closed. [7] Method according to the preceding claim, characterized by , that prior to the production of the clip connection, an electrolyte is filled into the battery cell housing (10) through the cell terminal opening.

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