Method for closing a round battery cell, and round battery cell

Abstract

The invention relates to a method for closing a round battery cell (2), comprising a substantially cylindrical housing (5), which is closed at one end by a base (6) having a connection element (7), and at another end has an opening (11), characterised by the steps of: - arranging a contacting plate (1) at one end of a rolling element (8); - welding the contacting plate (1) via at least one weld point to the anode element of the rolling element (8); - introducing the rolling element (8) with a contact element (9) at the front through the opening (11) into the housing (5), whereby the contacting plate (1) comes into contact with the housing (5) at a housing region (12); - welding the contacting plate (1) to the housing (5) along the housing region (12); - arranging a cover (13) on the contacting plate (1); and - welding the cover (13) to the housing (5) and / or the contacting plate (1). The invention also relates to a round battery cell (2).

Description

[0001] Method for closing a round battery cell and round battery cell

[0002] The invention relates to a method for sealing a round battery cell according to the preamble of patent claim 1. Furthermore, the invention relates to a round battery cell according to patent claim 8.

[0003] Round battery cells have numerous applications and are particularly used in traction batteries for motor vehicles. When used in traction batteries, and thus for electromobility, it is desirable for the volumetric energy density of each round battery cell to be particularly high.

[0004] According to the state of the art, round battery cells (or round cells for short) are sealed by crimping, a joining process in which two components, such as the battery casing and cover, are joined together through plastic deformation. Crimping involves, for example, flanging, squeezing, crimping, and / or folding. DE 10 2013 021 203 A1 shows a single cell for a battery.

[0005] A disadvantage of crimping is that, for example, additional installation space and / or housing material is required for crimping the housing components. This involves the electrical contacting of separate contact elements that exist in addition to a cover plate, which negatively impacts the volumetric energy density of the cylindrical cell.

[0006] The object of the present invention is therefore to provide a method for closing a round battery cell and a round battery cell, by which the volumetric energy density of the round battery cell can be made particularly high in a particularly advantageous manner. This object is achieved according to the invention by the subject matter of the independent patent claims. Advantageous embodiments and further developments of the invention are specified in the dependent patent claims as well as in the description and drawings.

[0007] A first aspect of the invention relates to a method for closing a round battery cell. The round battery cell comprises a substantially cylindrical housing which is closed at one end by a base having a connection element, and has an opening at another end. The housing material is, for example, sheet metal, which may, for example, have a coating, and its shape corresponds to a barrel-shaped sleeve with a base. The base can be formed integrally with the cylindrical outer surface of the housing. The connection element is, in particular, a contact for a cathode element of the round battery cell and serves for contacting and is therefore designed in such a way that it passes through the base or is arranged in a centered opening in the base.“Substantially cylindrical” means that slight deviations from a circular base, which the floor in particular has, are possible; for example, a slightly elliptical shape can be realized.

[0008] To ensure that the round battery cell can be closed particularly advantageously, for example, thereby advantageously saving installation space, the method according to the invention comprises several steps. In a first step, a contact plate is arranged transversely to a rolling direction at one end of a rolling element, which is rolled from a separator element, a cathode element, and an anode element, and to which a contact element is arranged and / or attached at another end. The contact element is in particular connected to the cathode element.

[0009] The contact plate is essentially round or circular, with a diameter, in particular an outer diameter, of the contact plate essentially corresponding to the inner and / or outer diameter of the cylindrical housing. The rolling element is called a Swiss roll or, in English, a jelly roll because its cross-section is reminiscent of a Swiss roll. In the rolling element, an insulating film, a thin layer of anode material, a separator layer, and a cathode material are usually layered and rolled in order to subsequently be inserted into a hollow cylindrical housing, such as the housing. The rolling element is particularly advantageous for use in rechargeable batteries.

[0010] In a second step of the method, the contact plate is welded or bonded to the anode element of the rolling element via at least one welding point. During the welding process, the contact plate, which is previously arranged in a planar manner transverse to the rolling direction, is thus fixed to the rolling element.

[0011] In a third step, the rolling element is inserted with the contact element first through the opening into the housing. As a result, the contact element comes into contact with the connection element, in particular to establish electrical contact between the contact element and the connection element and thus between the cathode element and the connection element, and the contact plate comes into contact with the housing at a housing edge or housing region adjacent to the opening. The contact element is arranged at the end of the rolling element opposite the contact plate. The housing edge or the housing region can be arranged on a top side of the housing, i.e. on the side of the housing opposite the bottom and / or on an inside of the housing.

[0012] In a fourth step, the contact plate is welded to the housing, in particular circumferentially along the housing area or particularly where the contact between the contact plate and the housing is formed. In a fifth step, a cover is arranged on the contact plate. Finally, in a sixth step, the cover is welded to the housing and / or the contact plate.

[0013] In other words, in the method, the round contact plate is connected to the anode element at the other end of the rolling element, which has the contact element at one end, in particular over its entire surface and by welding via at least one weld point. The rolling element is then inserted into the housing with the contact element in front through the opening, whereby the contact element comes into contact with the connection element and the contact plate comes into contact with the housing at a housing edge or housing area adjacent to the opening. A weld seam is drawn along the housing edge, or where there is contact between the contact plate and the housing. A cover is then placed on the contact plate and welded to the housing and / or the contact plate.

[0014] The contact plate is designed in particular in such a way that it can assume part of the lid or a cover plate and thus functions of the lid. In particular, the contact plate is made of copper and is welded to the so-called copper side of the jelly roll, in particular by laser welding.

[0015] The method according to the invention offers the advantage that the round battery cell can be sealed in a particularly advantageous manner, allowing it to be designed with a particularly high energy density. A further advantage of the method according to the invention is that unnecessary installation space and / or housing material can be saved.

[0016] In an advantageous embodiment of the invention, the welding is performed by laser welding or the welding is laser welding. Laser welding or laser beam welding is a welding process in which the energy for melting the components to be welded (e.g., the housing) is supplied via a laser beam. It is particularly suitable for fast welding or high welding speeds. Furthermore, it is suitable for forming narrow and / or slim weld seams, which makes it particularly advantageous for sealing round battery cells.

[0017] In a further advantageous embodiment of the invention, the welding of the contact plate to the housing and the welding of the cover to the housing and / or the contact plate are carried out simultaneously or simultaneously. In other words, the welding of the cover assembly (contact plate, cover) to the housing takes place in a single operation. This results in the advantage that the process can be carried out particularly efficiently. A further advantage is that the process can be carried out particularly quickly.

[0018] In a further advantageous embodiment of the invention, the outer diameter of the cover is smaller than the outer diameter of the contact plate, and the cover is welded to the contact plate, particularly circumferentially. The cover and the contact plate are aligned centrally relative to one another, so that their centers overlap. As a result, the contact plate, when welded to the housing, protrudes from the cover below the cover. This results in the advantage that the round battery cell can be designed with a particularly small installation space, resulting in a particularly high energy density.

[0019] In a further advantageous embodiment of the invention, the cover has a cylindrical casing element on its circumference, which is placed over the housing on the side of the opening and welded to it, in particular circumferentially. In other words, the cover itself is designed as a cylinder, with its inner diameter being greater than or equal to the outer diameter of the housing and its height or longitudinal direction being significantly shorter than that of the housing. This results in the advantage that, due to the overlap of the cylindrical casing element with the housing, the round cell can be sealed in such a way that the round battery cell is particularly mechanically resilient.

[0020] In a further advantageous embodiment of the invention, the contact plate has an outer peripheral region of increased material density which is melted during welding in such a way that both the cover and the housing are welded to this region. In other words, a particularly annular region is provided which is arranged on an outer side of the contact plate and serves for welding. This material region thus essentially fulfills the function of a welding filler material. The material thickness of the contact plate is selected such that the weld metal, i.e. the contact plate and / or the housing for welding, does not require additional welding filler materials. This results in the advantage that a weld seam can be formed particularly advantageously. Another advantage is that the closure can be carried out with particularly little installation space, since three weld metals can be joined together with a single weld seam.

[0021] In a further advantageous embodiment of the invention, the contact plate has an outer peripheral region of increased material thickness which is melted in such a way that the cover is welded to the housing through this region. In other words, the contact plate is not welded directly to the housing; instead, welding is carried out through the cover to the contact plate and the cover itself is welded to the housing. This results in the advantage that the round battery cell can be closed particularly advantageously. A second aspect of the invention relates to a round battery cell with a substantially cylindrical housing which is closed at one end by a base having a connection element and in which a contact plate is arranged at another end. A rolling element which is rolled from a separator element, a cathode element and an anode element is arranged in the housing.The round battery cell is advantageously sealed by means of a method according to the first aspect of the invention.

[0022] Advantages and advantageous embodiments of the first aspect of the invention are to be regarded as advantages and advantageous embodiments of the second aspect of the invention and vice versa.

[0023] In an advantageous embodiment of the invention, the contact plate has at least one fluid-permeable recess. In other words, the contact plate has at least one opening that is permeable to gas and / or electrolyte. For the sake of completeness, it should be mentioned here that the round battery cell is generally filled with an electrolyte before final sealing, which electrolyte is present in particular in the liquid state under normal or standard conditions. This results in the advantage that the contact plate can particularly advantageously establish contact with the anode element and, at the same time, can be arranged in a particularly fail-safe manner.

[0024] In a further advantageous embodiment of the invention, the contact plate has at least two regions of different material thickness, each of the regions being welded to a different component of the round battery cell. In other words, there is, for example, a thick region of the contact plate and a thin region of the contact plate, with the thin region being welded, for example, to the anode element and the thick region to the housing. This results in the advantage that the amount of material required to form the respective weld seam can be provided by the contact plate in a particularly advantageous manner without the need for additional welding material. The round battery cell can thus be designed with particularly efficient shape.

[0025] Further features of the invention emerge from the claims, the figures, and the description of the figures. The features and combinations of features mentioned above in the description, as well as the features and combinations of features mentioned below in the description of the figures and / or shown alone in the figures, can be used not only in the respective specified combination, but also in other combinations or on their own.

[0026] The invention will now be explained in more detail using a preferred embodiment and with reference to the drawings. They show:

[0027] Fig. 1 schematic plan view of a contact plate, which is used for

[0028] designed to close a round battery cell;

[0029] Fig. 2 schematic sectional view through the battery round cell with the

[0030] Contact plate according to Fig. 1;

[0031] Fig. 3 schematic sectional view through the battery round cell with a first

[0032] Design of a lid for closing the round battery cell;

[0033] Fig. 4 schematic sectional view through the round battery cell with a second embodiment of the lid for closing the round battery cell;

[0034] Fig. 5 schematic sectional views through the round battery cell with a second embodiment of the contact plate before and after welding with a third embodiment of the cover; and

[0035] Fig. 6 schematic sectional view through the round battery cell with a second embodiment of the lid for closing the round battery cell.

[0036] Fig. 1 shows a schematic plan view of a contact plate 1, made for example from copper, which is used to close a round battery cell 2 and thus in a method for closing the round battery cell 2. The figures are intended to illustrate this method, which is particularly advantageous for closing or sealing the round battery cell 2. With this method, the round battery cell 2 can be designed, for example, with particularly little installation space and thus with a particularly high volumetric energy density. For this purpose, it can be advantageous if the contact plate 1 has different regions 3, each of which has a different material thickness. Furthermore, the contact plate can have at least one fluid-permeable recess 4.

[0037] Fig. 2 shows in a schematic sectional view the round battery cell 2 in an unlocked state, comprising a housing 5 with a base 6, on which a connection element 7 is arranged and the base 6 closes the particularly cylindrical housing 5 at one end.

[0038] The process for sealing the round battery cell 2 comprises several steps:

[0039] In a first step, the essentially round contact plate 1 is arranged transversely to the rolling direction at one end of a rolling element 8, which is rolled from a separator element, a cathode element, and an anode element. A contact element 9 is arranged at the other end of the rolling element 8, which is connected in particular to the cathode element of the rolling element 8.

[0040] In a second step, the contact plate 1 is welded to the anode element of the rolling element 8 via at least one welding point, represented by a welding point marking 10.

[0041] In the schematic sectional view of Fig. 2, a third step of the method is carried out, in which the rolling element 8, with the contact element 9 in front, is inserted through an opening 11 of the housing 5 into the latter, whereby the contact element 9 comes into contact with the connection element 7 and the contact plate 1 comes into contact with the housing 5 at a housing edge or housing region 12 adjacent to the opening 11. By the contact element 9 coming into contact with the connection element 7, the positive pole of the round battery cell 2 is essentially provided. At least part of the contact plate 1 provides the negative pole of the round battery cell 2 by welding to the anode element.

[0042] Further steps, steps 4 to 6, of the method for closing the round battery cell 2 are now described with reference to the schematic sectional view in Fig. 3. In the fourth step, the contact plate 1 is welded to the housing 5, in particular circumferentially, along the housing edge or the housing region 12 and thus where contact between the contact plate 1 and the housing was created by the penetration of the rolling element 8 into the housing 5. The welding is likewise represented by a weld spot marking 10. In the fifth step, a cover 13 is now arranged on the contact plate 1. Finally, in a sixth step, the cover 13 is welded to the housing 5 and / or the contact plate 1, this also being represented by a weld spot marking 10.The cover 13 is twisted in particular in the event that a weld seam between the contact plate and the housing 5 is not completely tight.

[0043] As shown in Fig. 3, the cover 13 is welded inside the contact plate 1 so that an outer diameter of the cover 13 is smaller than an outer diameter of the contact plate 1. The cover 13 is welded to the contact plate 1 to close the round battery cell 2.

[0044] Fig. 4 shows a schematic sectional view of the round battery cell 2 with another embodiment of the cover 13. Here, the cover 13 is designed such that it is slipped over the housing 5 and completely covers the contact plate 1. The cover 13 is welded directly to the housing 5 at the sides, as indicated by the welding spot marking 10. Thus, the cover 13, which has a cylindrical shell element 14 on its circumference, is welded to the shell element 14 on the housing 5 after it has been slipped over the latter.

[0045] The difference between the left and right round battery cells 2 shown in Fig. 5 is the state of welding. The left round battery cell 2 shows the cover 13 unwelded, while the right round battery cell 2 shows the cover 13 welded. In the embodiment of Fig. 5, the contact plate 1, which has an increased material thickness on the outer peripheral region 3, is melted for welding in such a way that both the cover 13 and the housing 5 are connected to this region 3. In this embodiment, it is particularly suitable for the welding of the contact plate 1 to the housing 5 and the welding of the cover 13 to the housing 5 and / or the contact plate 1 to take place together or simultaneously. The respective welding is advantageously carried out as laser welding.

[0046] Finally, Fig. 6 also shows, in a schematic sectional view, a raised region 3 of the contact plate 1 on the outer circumference, which is melted in such a way that the cover 13 is welded to the housing 5 through the region 3. In other words, the contact plate 1 is not welded to the housing 5, at least not initially; instead, it is welded through the cover 13 to the contact plate 1 and the cover 13 itself is welded to the housing 5 (via the contact plate 1), whereby, for example, the round battery cell 2 can be closed particularly advantageously.

[0047] The method shown with the various configurations of the cover 13 enables the round battery cell 2 to be closed, wherein the contact plate 1 also takes over parts of the function of the cover 13 itself and thus enables a particularly space- and / or housing-material-saving closure.

[0048] The contact plate 1 has areas 3 of different material thicknesses, which are optimized for the respective welding processes. Furthermore, the contact plate 1 can have recesses 4 for gas and electrolyte permeability. In summary, the process is as follows: The rolling element 8, or jelly roll, is inserted into the housing 5 so that the contact plate 1 rests on the edge of the housing 5. This contact surface is provided with a particularly circumferential, tight laser weld seam. Since the weld seam between the contact plate 1 and the rolling element 8 presumably cannot always be made gas-tight, the cover 13 is provided.

[0049] In the variant shown in Fig. 3, welding takes place inside the contact plate 1. In the variant shown in Fig. 4, the cover 13 is placed over the housing 5 and completely covers the contact plate 1. In the variant shown in Fig. 5, the cover assembly or housing 5 and the contact plate are welded in a single operation, so that very few weld seams are required. In the variants shown in Fig. 6, the contact plate 1 is melted by welding through the cover 13.

[0050] The illustrated embodiments of the method for closing the round cell allow for particularly advantageous space savings and thus a particularly high volumetric energy density of the round battery cell 2 can be achieved.

[0051] Contact plate

[0052] Round battery cell

[0053] Area

[0054] recess

[0055] Housing

[0056] Floor

[0057] connecting element

[0058] Round element

[0059] Contact element

[0060] Weld spot marking

[0061] opening

[0062] Housing area

[0063] Lid

[0064] Sheath element

Claims

Claims Method for closing a cylindrical battery cell (2), with a substantially cylindrical housing (5), which is closed at one end with a base (6) having a connection element (7), and has an opening (11) at another end, characterized by the steps: - Arranging a contact plate (1) transversely to the rolling direction at one end of a rolling element (8) which is rolled from a separator element, a cathode element and an anode element, and on which a contact element (9) is arranged at another end; - Welding the contact plate (1) to the anode element of the rolling element (8) via at least one weld point; - Inserting the rolling element (8) with the contact element (9) forward through the opening (11) into the housing (5), whereby the contact element (9) comes into contact with the connecting element (7) and the contact plate (1) comes into contact with the housing (5) at a housing area (12) adjacent to the opening (11); - Welding the contact plate (1) to the housing (5) along the housing area (12); - Arranging a cover (13) on the contact plate (1); and - Welding the cover (13) to the housing (5) and / or the contact plate (1). Method according to claim 1, characterized in that the welding is carried out by laser welding. Method according to claim 1 or 2, characterized in that the welding of the contact plate (1) to the housing (5) and the welding of the cover (13) to the housing (5) and / or the contact plate (1) are carried out simultaneously. A method according to any one of the preceding claims, characterized in that the outer diameter of the cover (13) is smaller than the outer diameter of the contact plate (1) and the cover (13) is welded to the contact plate (1), in particular circumferentially. A method according to any one of the preceding claims, characterized in that the cover (13) has a cylindrical outer shell element (14) on its circumference, which is placed over the housing (5) at the opening (11) and welded to it, in particular circumferentially. A method according to any one of the preceding claims, characterized in that the contact plate (1) has an outer circumferential region (3) of increased material thickness, which is melted in such a way that both the cover (13) and the housing (5) are welded to this region (3).A method according to any one of the preceding claims, characterized in that the contact plate (1) has an outer circumferential region (3) of increased material thickness, which is melted such that the cover (13) is welded to the housing (5) through the region (3). A cylindrical battery cell (2) with a substantially cylindrical housing (5) which is closed at one end with a base (6) having a connecting element (7) and in which a contact plate (1) is arranged at another end, wherein a rolling element (8) which is rolled from a separator element, a cathode element and an anode element is arranged in the housing (5) and the cylindrical battery cell (2) is closed by means of a method according to any one of the preceding claims. A cylindrical battery cell (2) according to claim 8, characterized in that. The contact plate (1) has at least one fluid-permeable recess (4). A cylindrical battery cell (2) according to claim 8 or 9, characterized in that the contact plate (1) has at least two areas (3) of different material thicknesses, each area (3) being welded to a different component of the cylindrical battery cell (2).

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