Assembly, electric cell, and method for producing an assembly for an electric cell

Abstract

The invention relates to an assembly (1), an electric cell, and a method for producing an assembly (1) for an electric cell. The method comprises the steps of: inserting a sealing insulation collar (3) into an opening (4) in a cell case (5) and inserting a terminal pin (6) into the opening (4), wherein the terminal pin (6) is arranged in the insulation collar (3), and a thermally stable insulation layer (7) facing the insulation collar (3) is provided on a surface of the terminal pin (6) and / or of the cell case (5).

Description

[0001] Assembly, electrical cell and method for producing an assembly for an electrical cell

[0002] Description

[0003] The present invention relates to an assembly, an electrical cell, and a method for manufacturing an assembly for an electrical cell. In particular, the present invention relates to protecting the electrical cell against electrical short circuits in the event of a thermal anomaly.

[0004] The electrification of personal transport is currently progressing rapidly. One concept involves using round cells or prismatic cells with a hard case to store traction energy. In battery cells, the poles / terminals are usually electrically insulated from each other by polymers / polyamide, and the cell can is sealed in the area of ​​the connection pin (also known as a "rivet terminal"). In the event of a thermal anomaly, this seal / insulation can be damaged, resulting in an electrical short circuit between the connection pin and the cell can. The resulting high temperatures and short circuits can lead to other electrical cells in the network becoming infected (thermal runaway). In this case, neighboring cells can also become so hot that the electrical insulation / seal is damaged, and the neighboring cells independently develop a short circuit.

[0005] It is an object of the present invention to avoid the risk of a short circuit in case of overheating of the insulation / seal.

[0006] The aforementioned object is achieved according to the invention by the subject matter of the independent claims. The dependent claims show preferred developments of the invention. According to a first aspect of the present invention, a method for producing an assembly for an electrical cell, which can also be referred to as a battery cell or electrochemical cell, is proposed. The assembly can be understood as a cover assembly or region of the electrical cell which has an electrical connection pin (terminal or pole). The electrical cell can be designed as an electro-chemical round cell. In particular, it can be provided for storing traction energy for means of transport. In a first step, an insulating collar is inserted into an opening in the cell can. This insulating collar seals the opening and electrically insulates a connection pin in the opening from the wall of the cell can.In addition, the connection pin is inserted into the opening. The connection pin can be designed as a rivet and is also referred to as a “rivet pin” in English. In the form of a rivet, the connection pin can be inserted into the opening or inserted into the insulation collar and then deformed such that it is secured in the opening of the cell can. The insulation collar can be designed to be less thermally stable than would be necessary in the event of faults or accidents. This makes it possible to provide the insulation collar in a cost-effective and process-technically simple manner. According to the invention, a thermally stable insulation layer facing the insulation collar is therefore additionally provided on a surface of the connection pin and / or on a surface of the cell can. The thermal stability of the insulation layer can be achieved in particular due to the material selection or material combination.Alternatively or additionally, a treatment of a metallic surface (e.g., the cell can and / or a predefined area of ​​the connection pin) can be provided to electrically passivate the constriction between the cell can and the connection pin. Even if the insulation collar develops defects or shrinks due to thermal incidents, thermal runaway of the electrical cell can be prevented by keeping the short-circuit currents between the connection pin and the cell can low. In addition, the thermal resistance of the insulation is increased during and after a thermal event. If the insulation on an already defective cell fails after a thermal event, the cells connected in parallel with this cell can also experience this short circuit and, via this short circuit, can also be triggered into the thermal event.The insulation layer is therefore at least designed to ensure such high resistances upon contact or proximity between the connection pin and the cell cup that thermal runaway of the electrical cell or a collection of electrical cells (heat propagation) is not to be feared. The thermally stable insulation layer can thus be provided as a component of the connection pin and / or as a component of the cell cup and / or as a component of an additional element or as an additional element. This makes the electrical cell more secure, or a combination of electrical cells, protected against the risk of thermal runaway of several adjacent and interconnected electrical cells.

[0007] Preferably, the insulation collar may have a lower thermal stability than the thermally stable insulation layer. In any case, in a thermally critical situation, the insulation collar will fail first, before the thermally stable insulation layer is damaged or displaced from its original position. This effectively prevents an electrical short circuit within the electrical cell in question.

[0008] For example, the thermally stable insulation layer can be provided by a first ring element and / or a second ring element. The ring element can be designed as an annular disc, circular disc, shim disc, or similar. The ring element does not have to have a flat shape, but can have collars, grooves, or other structures and features that are advantageous in the assembly. The first ring element can be arranged between the connection pin and the insulation collar, or between the cell cup and the insulation collar. The same applies to the second ring element. An axial extension of the ring element with respect to the electrical cell can be significantly shorter than a radial extension of the ring element. In particular, the radial extension can be ten times, fifteen times, or twenty times the axial extension. The same applies to the second ring element.The first ring element and / or the second ring element can be made of a liquid crystal polymer and / or a ceramic and / or a composite material, in particular a polymer composite material and / or polyimide, or can comprise the aforementioned materials / combinations of materials. These thermally significantly more stable materials ensure dimensional stability and heat resistance compared to the comparatively heat-sensitive insulation collar, which can therefore be better adapted to the sealing function.

[0009] The first ring element can be arranged outside the cell cup or on its outer side, while the second ring element can be arranged inside the cell cup, in particular on its inner side. In particular, the ring elements can be arranged between a flange of the connection pin and a surface of the lid of the cell cup and / or surround, preferably completely surround, the connection pin and / or the opening in the cell cup.

[0010] The thermally stable insulation layer can have a structure that surrounds the opening of the cell cup. In particular, a first thermally stable insulation layer can be arranged in the region of an outer side of the cell cup, while alternatively or additionally, a second thermally stable insulation layer surrounds the opening on an inner side of the cell cup. Thus, the connection pin and / or the insulation collar are also enclosed or at least lined by the thermally stable insulation layer.

[0011] Preferably, the second ring element (within the cell cup) has a spacer configured to bear against a current collecting plate of the electrical cell and to maintain a distance from the current collecting plate. For this purpose, the spacer can be configured as structures or webs extending in the axial direction of the electrical cell, which are particularly perpendicular to the second ring element. These spacers can also serve to stiffen the second ring element, thereby counteracting deformations under the action of force or operational pressure differences.

[0012] Preferably, the second ring element can have a collar that encloses a structure of the connecting pin. This collar can predefine a radial position of the second ring element relative to the connecting pin and prevent displacement of the two elements relative to each other as long as the connecting pin is enclosed.

[0013] As already indicated above, the thermally stable insulation layer can be created by processing a surface of the terminal pin and / or the cell can lid. For example, chemical vapor deposition and / or sputtering and / or plasma treatment and / or anodizing and / or anodizing can be used to achieve the electrical or galvanic passivation of the surface to provide the thermally stable insulation layer. In particular, an area of ​​the terminal pin facing the insulation collar can be passivated, while flange surfaces toward the jelly roll or toward the cell periphery are left bare or untreated to reduce electrical contact resistance and conduction losses, as well as heat generation.

[0014] Preferably, a pressure distribution disc (loading disc) can be arranged on the connecting pin, so that the pressure distribution disc engages in a circumferential groove. The groove can, for example, be provided as a circumferential recess or groove with a semicircular cross-section in a mechanically expanded section of the inner connecting pin. In other words, the end of the connecting pin whose diameter is enlarged upon expansion of the connecting pin (usually facing the jelly roll) can be provided with the circumferential groove. Alternatively or additionally, the connecting pin, in conjunction with the insulation collar, can form the aforementioned circumferential groove, in which an inner edge of the pressure distribution disc is arranged.By arranging the inner edge of the pressure distribution disc in the circumferential groove, it is possible to prevent the connection pin from involuntarily breaking the positive connection between the connection pin and the cell cup lid due to deformation in the area of ​​the opening in the cell cup lid, for example if increased internal pressure tends to press the connection pin out of the cell cup. The pressure distribution disc can be made of steel, in particular stainless steel, for example, which results in increased mechanical strength compared to the cell cup lid usually made of aluminum. According to a second aspect of the present invention, an assembly is proposed which is obtainable according to the aforementioned method. The assembly can be a component of an electric cell or of an electric traction energy storage device with multiple electric cells.The features, combinations of features and the advantages resulting from them are therefore similar to those of the method described above, so that reference is made to the above statements to avoid repetition.

[0015] According to a third aspect of the present invention, an electric cell is proposed which comprises an assembly as described above as the second aspect of the invention. The electric cell is supplemented, for example, by a current collecting disc and a jelly roll / electrolyte such that the electric cell is a fully functional (traction) energy storage device, which can be used to supply energy to a drive train of an electrically driven means of transport.

[0016] Further details, features, and advantages of the invention will become apparent from the following description and the figures. They show:

[0017] Fig. 1 is a sectional view of an assembly of an electrical cell according to the prior art;

[0018] Fig. 2 is a sectional view of an assembly of an electrical cell according to a first embodiment;

[0019] Fig. 3 is a sectional view of an assembly of an electrical cell according to a second embodiment;

[0020] Fig. 4 is a sectional view of an assembly of an electrical cell according to a third embodiment; Fig. 5 is a detailed view of a circumferential groove in a structure of a connection pin for securing a pressure distribution disc;

[0021] Fig. 6 is a detailed view of a circumferential groove which is formed between a structure of a connection pin and an insulation collar and in which a pressure distribution disc is arranged;

[0022] Fig. 7 is a sectional view of a fourth embodiment of an assembly designed according to the invention;

[0023] Fig. 8 is a perspective view of an undeformed connection pin with a passivated surface in the region of an opening of a cell cup lid;

[0024] Fig. 9 shows the configuration shown in Fig. 8 after a 180° rotation of the connection pin;

[0025] Fig. 10 is a schematic sectional view of the connection pin shown in Fig. 8 and Fig. 9 with a partially passivated surface;

[0026] Fig. 11 is a perspective view of a cell cup lid with a partially passivated surface in the area of ​​an opening;

[0027] Fig. 12 is a schematic sectional view of the cell cup lid according to Fig. 11;

[0028] Fig. 13 is a sectional side view of a fifth embodiment of an assembly according to the invention before deformation of the connection pin;

[0029] Fig. 14 shows the configuration shown in Fig. 13 after partial deformation of the connecting pin for fastening in an opening of the cell cup lid; Fig. 15 shows the arrangement shown in Fig. 14 after complete deformation of the connecting pin;

[0030] Fig. 16 is an exploded perspective view of a sixth embodiment of an assembly according to the invention in an electrical cell according to the invention;

[0031] Fig. 17 is a sectional side view of the exploded view shown in Fig. 16 after assembly of the components; and

[0032] Fig. 18 is a flowchart illustrating steps of an embodiment of a method according to the invention for producing an assembly for an electrical cell.

[0033] Fig. 1 shows an assembly 1 for an electrical cell embedded in the base of a cell can, in which the base of the cell can 5 has an opening into which a connection pin 6 is inserted. The connection pin 6 is surrounded by an insulating collar 3, by which the cell can 5 is electrically insulated from the connection pin 6 and hermetically sealed. Due to the low thermal stability of the insulating collar 3, if the assembly 1 becomes extremely hot, the insulating effect and / or position of the insulating collar 3 can be impaired, resulting in a short circuit between the connection pin 6 and the cell can 5.

[0034] Fig. 2 shows a modification according to the invention of the assembly 1 shown in Fig. 1. The region of the insulation collar 3 lying outside the cell cup 5 has a smaller diameter, so that space is created in the radial direction between the outer flange of the connection pin 6 and the cell cup 5 in order to insert a first ring element 8 as a thermally stable insulation layer 7. The first ring element 8 has a collar 12 which surrounds or encloses the outer part of the connection pin 6 over approximately one-third of its total height. In this way, a radial relative position is provided between the first ring element 8 and the connection pin 6. Fig. 3 shows the region of the insulation collar 3 located outside the cell cup 5.2, wherein the insulation collar 3 has a flange only on the outside, while a pressure distribution disc 13 and a second ring element 9 with a thermally stable insulation layer 7 are provided between the current collecting disc 11 and the cell cup 5, stacked one on top of the other in the axial direction. The second ring element 9 has a circular disc-shaped configuration without a collar or the like. A section of the connection pin 6 facing the current collecting disc 11, together with the insulation collar 3, forms a circumferential groove for spatially securing the pressure distribution disc 13.

[0035] This arrangement is shown in detail in Fig. 6.

[0036] Fig. 4 shows the arrangement illustrated in Fig. 3, with a circumferential groove 14 now provided in the section of the connection pin 6 closest to the current collecting disc 11 for spatially securing the pressure distribution disc 13. This prevents axial pressure on the insulation collar 3.

[0037] Fig. 5 shows this representation in detail.

[0038] Fig. 7 shows a sectional view of an embodiment of an assembly 1 for an electrical cell, in which a second ring element 9 is designed with a thermally stable insulation layer 7 with spacers 10 to ensure a spatial axial distance between the cell cup 5 or the cell cup lid and the current collecting disc 11. The spacers 10 are designed as two concentric hollow cylinders arranged concentrically to the cell cup 5.

[0039] Fig. 8 shows a perspective view of a connection pin 6, the flange of which facing the cell cup 5 and the region to be arranged within the opening 4 are each provided with a thermally stable insulation layer 7. This layer is achieved by processing the bare metal and highly electrically conductive material of the connection pin 6. For example, chemical vapor deposition and / or sputtering can change the electrical resistance of the surface in such a way that a high contact resistance is achieved for the insulation layer 7.

[0040] Fig. 9 shows the view shown in Fig. 8 after a 180° rotation (upside down view).

[0041] Fig. 10 shows the arrangement shown in Fig. 8 in a schematic sectional view.

[0042] Fig. 11 shows a perspective view of a cell cup 5, whose opening 4 is lined with a thermally stable insulation layer 7. For this purpose, the bare metal material of the cell cup lid has been passivated as described above.

[0043] Fig. 12 shows the arrangement illustrated in Fig. 11 in a side section. The thermally stable insulation layer 7 covers approximately one-third of the radial extent of the cell cup lid on the outside and approximately two-thirds in the area of ​​the cell cup lid's inside.

[0044] Fig. 13 shows a first sectional side view of a fifth exemplary embodiment of an assembly 1 according to the invention, which is based on the elements shown in Figs. 8 to 12. The connecting pin 6 has already been inserted into the opening of the cell cup 5 and is electrically insulated and sealed from the cell cup lid by an insulating collar 3 designed according to the prior art. The region of the connecting pin 6 inserted into the cell cup 5, however, is not yet deformed.

[0045] In other words, there is no positive connection between the cell cup cover and the connection pin 6.

[0046] Fig. 14 shows the arrangement illustrated in Fig. 13 after a partial expansion of the section of the connecting pin 6 inserted into the cell cup 5. The connecting pin 6 has already been positively secured in the opening of the cell cup 5. However, the opening in the cell cup 5 has not yet been adequately sealed because the insulating collar 3 has not yet been sufficiently crimped. Fig. 15 shows the arrangement illustrated in Fig. 14 after the connecting pin 6 has been completely deformed. Now, by completely crimping the insulating collar 3, a hermetically sealed volume of the cell cup 5 has been achieved.

[0047] Fig. 16 shows a perspective exploded view of a sixth embodiment of an assembly 1 according to the invention for an electrical cell 2. From top to bottom, the elements connection pin 6, first ring element 8 with thermally stable insulation layer 7, insulation collar 3, opening 4 in the cell cup 5, second ring element 9 with thermally stable insulation layer 7, insulator disk 15, pressure distribution disk 13 and current collecting disk 11 are shown.

[0048] Fig. 17 shows the arrangement shown in Fig. 16 after the arrangement is assembled / completed.

[0049] Fig. 18 shows steps of an embodiment of a method according to the invention for producing an assembly for an electrical cell. In step 100, a sealing insulating collar is inserted into an opening of a cell can. The insulating collar lines an inner flange surface, an outer flange surface, and a surface of a cell can lid connecting the two flange surfaces. In step 200, a connecting pin is inserted into the opening 4 or into the insulating collar 3. This can be done in particular from outside the cell can. From an inner side of the cell can, a pressure distribution disk is then placed onto the connecting pin in step 300 and engages in a circumferential groove of the connecting pin.In step 400, the section of the connection pin provided with the pressure distribution disk is deformed such that the connection pin, together with the insulation collar and the cell cup lid, provides a hermetic seal for the opening in the cell cup lid. List of reference symbols:

[0050] 1 assembly

[0051] 2 Electric cell

[0052] 3 insulation collars

[0053] 4 Opening

[0054] 5 cell cups

[0055] 6 connection pins

[0056] 7 Thermally stable insulation layer

[0057] 8 First ring element

[0058] 9 Second ring element

[0059] 10 spacers

[0060] 11 Current collecting disc

[0061] 12 collars

[0062] 13 Pressure distribution disc

[0063] 14 grooves

[0064] 15 Insulator disc

[0065] 100-400 process steps

Claims

Patent claims:

1. A method for producing an assembly (1) for an electrical cell (2) comprising: • Inserting (100) a sealing insulation collar (3) into an opening (4) in a cell cup (5) and • Inserting (200) a connection pin (6) into the opening (4), • wherein the connection pin (6) is arranged in the insulation collar (3), characterized in that • a thermally stable insulation layer (7) facing the insulation collar (3) is provided on a surface of the connection pin (6) and / or the cell cup (5).

2. The method according to claim 1, wherein the insulation collar (3) has a lower thermal stability than the thermally stable insulation layer (7).

3. The method according to claim 1 or 2, wherein the thermally stable insulation layer (7) is provided by a first ring element (8) and / or a second ring element (9), wherein the first ring element (8) is arranged between the connection pin (6) and the insulation collar (3) or is arranged between the cell cup (5) and the insulation collar (3), and / or wherein the second ring element (9) is arranged between the connection pin (6) and the insulation collar (3) or is arranged between the cell cup (5) and the insulation collar (3).

4. The method according to claim 3, wherein the first ring element (8) and / or the second ring element - Liquid crystal polymer and / or - Ceramics and / or - Composite material, in particular polymer composite material, and / or - polyimide.

5. The method according to claim 3 or 4, wherein - the first ring element (8) is arranged outside the cell cup (5) and / or the second ring element (9) is arranged inside the cell cup (5).

6. The method according to any one of claims 3 to 5, wherein - the second ring element (9) has a spacer (10) which is designed to bear against a current collecting disc (11) of the electrical cell (2) and / or - the first and / or the second ring element (8, 9) has a collar (12) which is designed to encompass a structure of the connection pin (6).

7. Method according to one of the preceding claims, wherein the insulation layer (7) is produced by machining a surface of the connection pin (6).

8. The method according to claim 7, wherein the processing - chemical vapor deposition and / or - Sputtering and / or - Plasma treatment and / or - Anodizing and / or - Anodizing included.

9. Method according to one of the preceding claims, further comprising - Arranging (300) a pressure distribution disc (13) on the connection pin (6) in such a way that the pressure distribution disc (13) engages in a circumferential groove (14) which - provided in the connection pin (6) and / or - is formed by the connection pin (6) and the insulation collar (3).

10. Assembly (1) obtainable by a method according to one of the preceding claims.

11. An electrical cell (2) comprising an assembly (1) according to claim 10.

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