Battery cell

Abstract

The invention relates to a battery cell (10) with a housing and an electrochemical cell (12) arranged within the housing, wherein the housing has a cylindrical basic shape corresponding to a general cylinder with a closed guide curve, comprising a base, a top surface parallel to the base, and a lateral surface. The housing has a cup-shaped first housing part (16) arranged in the region of the base and a portion of the lateral surface adjacent to the base, a cup-shaped second housing part (18) arranged in the region of the top surface and a portion of the lateral surface adjacent to the top surface, and a sleeve-shaped third housing part (20) arranged in the region of at least a portion of the lateral surface. The first and second housing parts (16, 18) are connected by the third housing part (20).

Description

[0001] The invention relates to a battery cell with a housing and an electrochemical cell arranged inside the housing.

[0002] Battery cells comprising a housing and an electrical cell arranged inside the housing are known from the prior art. For example, DE 10 2022 111 706 A1 discloses a battery whose housing has a cup-shaped housing part. With regard to mechanical stability, such housing parts are primarily manufactured from metallic materials. The ability of the housing to withstand pressure increases within the battery is a key reason for selecting a metallic material for the housing part. During the manufacture of the battery cell, the cup-shaped housing part is sealed at its open end. The electrical contact of the battery cell is typically made both via the base of the cup-shaped housing part and via components of the battery cell that seal the open end of the cup-shaped housing part.

[0003] To prevent a short circuit across the housing section, it is necessary to design the closure of the open end of the cup-shaped housing section in such a way as to provide electrical insulation in the area of ​​this closure. In practice, this leads to a comparatively complex construction of the battery cell in the area of ​​the closure, which must be manufactured using correspondingly complex processes. This applies particularly to the electrically conductive connection between the metal foils, which are components of the electrodes of the electrochemical cell, and those components of the accumulator that serve for the electrical contacting of the battery cell and are regularly referred to as the terminals of the battery cell.

[0004] In the case of the bottom of the cup-shaped housing part, this contacting can be carried out, for example, as described in the prior art cited above, by welding the metal foil of one of the electrodes of the electrochemical cell to the bottom of the cup-shaped housing part.

[0005] However, in the case of closing the open end of the cup-shaped housing part, comparatively complex designs are necessary, for example, the contacting of the metal foil by means of a disc-shaped contact element as described in the prior art cited above. This must be electrically insulated from the cup-shaped housing part; furthermore, an electrical connection must be established between the externally contactable terminal of the battery cell and this contact element.

[0006] While constructive solutions are known from the prior art, such as the use of glass-to-metal feedthroughs as shown, for example, in DE 10 2022 111 707 A1, it would nevertheless be desirable to simplify the construction of a battery cell and thus reduce the necessary manufacturing effort, particularly in the area of ​​electrical contacting the metal foils of the electrodes of the electrochemical cell.

[0007] The invention is therefore based on the objective of demonstrating a battery cell that is simpler in design and / or manufacture.

[0008] The problem is solved by a battery cell having the features of independent claim 1. The features of the dependent claims relate to advantageous embodiments.

[0009] The battery cell consists of a casing and an electrochemical cell located inside the casing. The battery cell is specifically a secondary battery. Such secondary batteries are also called accumulators and are characterized in particular by their rechargeability, allowing for a large number of charging cycles. The electrochemical cell can be, in particular, a lithium-ion cell.

[0010] The housing has a cylindrical basic shape corresponding to a general cylinder with a closed guide curve, comprising a base, a top surface parallel to the base, and a lateral surface. A cylindrical basic shape is understood to mean, in particular, that the outer contour of the housing may deviate from a perfect cylinder, especially in the area of ​​edges or functional elements that, for example, serve for electrical contacting or enable the battery cell to be sealed after filling with electrolyte. Examples of such deviations include, in particular, rounded edges, local indentations such as beads, and molded and / or attached contacts for electrically contacting the battery cell.

[0011] The housing comprises a cup-shaped first housing section. This first housing section is located in the area of ​​the base and a portion of the lateral surface adjacent to the base. The housing also comprises a cup-shaped second housing section. This second housing section is located in the area of ​​the top surface and a portion of the lateral surface adjacent to the top surface.

[0012] Furthermore, the housing has a sleeve-like third housing part, which is arranged in the area of ​​at least part of the outer surface. A sleeve-like third housing part is understood to be, in particular, a housing part that has the shape of a cylindrical shell. Specifically, the third housing part can be tubular.

[0013] The first and second housing parts are connected by the third housing part. The resulting assembly of the two cup-shaped and the sleeve-shaped housing parts creates a housing with a cylindrical base shape, which can be very simply designed in terms of its base and top surfaces.

[0014] The battery cell can have a cylindrical base shape corresponding to a circular cylinder, in particular a base shape corresponding to a vertical circular cylinder. A circular cylinder represents the special case of a general cylinder with a circle as its guide curve. In practice, such battery cells are referred to simply as cylindrical battery cells. A circular cylindrical base shape offers advantages, especially with regard to automated manufacturing. For example, planar components of the electrochemical cell, particularly the electrodes and / or a separator, can be wound spirally into circular cylindrical electrode windings. This can be done in efficient automated processes. The winding axis of the spiral winding is oriented parallel to the generatrix of the cylindrical base shape.The electrode windings thus formed can be easily inserted into the cylindrical cells, and the metal foils of the electrodes can be electrically connected to the bottoms of the cup-shaped housing parts.

[0015] Alternatively, the battery cell can have a cylindrical shape corresponding to a prism, in particular a shape corresponding to a right prism. A prism represents the special case of a general cylinder with a polygon as its guiding curve. Such battery cells are also called prismatic battery cells. Due to their shape, prismatic cells can be combined into relatively compact battery modules containing multiple battery cells.

[0016] In particular, a first metal foil of a first electrode of the electrochemical cell can be electrically connected to the first housing part and / or a second metal foil of a second electrode of the electrochemical cell can be electrically connected to the second housing part. The connection between the first metal foil and the first housing part is located, in particular, in the area of ​​the base of the cylindrical base. The connection between the second metal foil and the second housing part is located, in particular, in the area of ​​the top surface of the cylindrical base.

[0017] The connection of the first metal foil to the first housing part and / or the connection of the second metal foil to the second housing part can be a welded joint, in particular a laser welded joint, and / or an adhesive bond, in particular using an electrically conductive adhesive. The laser welded joint can be created, in particular, by applying a laser to the outside of the respective housing part.

[0018] In particular, the first housing part can be electrically isolated from the second housing part. Electrical insulation between the first and second housing parts allows both housing parts to be used for electrical contacting the electrochemical cell inside the housing.

[0019] The third housing part can be made of a non-conductive material. If the third housing part is made of a non-conductive material, it can contribute to and / or provide electrical insulation between the first and second housing parts. The third housing part can be made of plastic, in particular. A non-conductive third housing part can be manufactured cost-effectively from plastic. Specifically, the third housing part can be an injection-molded part. Injection molding allows for the cost-effective production of large quantities. This is particularly advantageous given that battery cells are regularly mass-produced in large quantities.

[0020] The first housing part and / or the second housing part can be made of a metallic material. Metallic materials, in addition to their high mechanical strength, also exhibit good electrical conductivity. This allows the first housing part and / or the second housing part to be used as part of the current path between an external electrical contact of the battery cell and an electrode of the battery cell.

[0021] The first housing part and / or the second housing part can be slid onto the third housing part. The first housing part and / or the second housing part is slid onto the third housing part in such a way that, in the area of ​​a portion of the cylindrical base's outer surface, the first and third housing parts and / or the second and third housing parts overlap. Such an overlap enables, in particular, the formation of a mechanically stable housing. Specifically, the third housing part is surrounded by the first and / or the second housing part in the area of ​​the respective overlap. This mechanically reinforces the third housing part, particularly against increasing pressure inside the housing.

[0022] The first housing part and / or the second housing part can be bonded to the third housing part. Such bonding creates a mechanically stable and, in particular, a tight connection between the housing parts. The bonding can be applied, especially in an overlap area between the first and third housing parts and / or the second and third housing parts, in the region of the cylindrical base surface. This allows for bonding over a large area.

[0023] The third housing part may have an outwardly projecting area. This outwardly projecting area may, in particular, surround the third housing part in a ring-like fashion. In the area of ​​the outwardly projecting area, the third housing part has a greater wall thickness than in the areas where the first and / or second housing part is slid onto the third housing part. This results in greater stability of the third housing part in the outwardly projecting area. The outwardly projecting area is, in particular, not surrounded by the first and / or second housing part.

[0024] The third housing part can have fiber reinforcement and / or a metallic reinforcing element. This allows the third housing part to be mechanically reinforced. The fiber reinforcement and / or the metallic reinforcing element is located, in particular, in an area of ​​the third housing part that is not, or at least not completely, surrounded by the first and / or second housing parts. This makes it possible to space the first and second housing parts apart, especially to ensure electrical insulation between them.At the same time, the reinforcement can create a housing that is still sufficiently stable overall, in which, in particular, the area of ​​the third housing part that is not reinforced by a surrounding first or second housing part is reinforced by the fiber reinforcement and / or the metallic reinforcing element in order to avoid a mechanical weak point of the housing at this point.

[0025] Particularly when the third housing part is an injection-molded part, the fiber reinforcement and / or the metallic reinforcing element can be overmolded with the third housing part. Overmolding, in particular, allows the fiber reinforcement and / or the metallic reinforcing element to be easily integrated into and / or bonded to the third housing part.

[0026] The outwardly projecting area can form a stop for the first and / or the second housing part. In this way, the outwardly projecting area enables a simple and cost-effective way to ensure the dimensional accuracy of the housing, as the first and / or second housing part are slid onto the third housing part until the stop is reached.

[0027] The third housing component can have a diffusion-retardant coating on an inward-facing surface. Diffusion-retardant coatings, particularly in combination with a third housing component made of plastic, can prevent water from diffusing through the battery cell housing. The diffusion-retardant coating can be a metallic coating, for example, made of aluminum or an aluminum alloy. Metallic coatings are particularly well-suited to preventing water diffusion and can be applied relatively easily to the surface of the third housing component.

[0028] A separator arranged in the area of ​​the lateral surface of the electrical cell can extend along the metallic coating at least far enough to form an electrically insulating barrier across the entire surface of the metallic coating between the metallic coating and the metallic components of the electrochemical cell. In this way, the separator forms, in particular, an electrically insulating barrier between the metallic coating and the first and / or second metal foil of the electrochemical cell. This prevents a short circuit within the battery cell caused by the metallic coating. The separator extends, in particular, in a direction parallel to the lateral surface of the cylindrical base, beyond the metallic coating in the direction of the base and / or top surface of the cylindrical base.

[0029] Further practical embodiments and advantages of the invention are described below in connection with the drawing. It shows: Fig. 1 A schematic cross-sectional view of an example battery cell

[0030] The exemplary battery cell 10 has a housing and an electrochemical cell 12 arranged inside the housing. The electrochemical cell 12 can be a cell wound spirally around a winding axis 14.

[0031] The housing has a cylindrical base shape corresponding to a general cylinder with a closed guide curve, comprising a base, a top surface parallel to the base, and a lateral surface. The housing includes a cup-shaped first housing part 16. This first housing part 16 is located in the area of ​​the base and a portion of the lateral surface of the cylindrical base that is adjacent to the base. The housing also includes a cup-shaped second housing part 18. This second housing part is located in the area of ​​the top surface and a portion of the lateral surface of the cylindrical base that is adjacent to the top surface. Finally, the housing includes a sleeve-shaped third housing part 20. This housing part 20 is located in the area of ​​a portion of the lateral surface of the cylindrical base. The first housing part 16 and the second housing part 18 are connected by the third housing part 20.

[0032] The battery cell 10 can have a circular cylindrical shape, as shown in the example. In particular, the direction X of the generatrix of the circular cylindrical shape can run parallel to the winding axis 14. In other words, the winding axis 14 can be arranged parallel to the direction X of the generatrix.

[0033] The electrochemical cell 12 can have a first metal foil 22 for contacting a first electrode of the electrochemical cell 12 and a second metal foil 24 for contacting a second electrode of the electrochemical cell 12.

[0034] As in the example shown, the first metal foil 22 can be connected to the first housing part 16, for example by welding. The first metal foil 22 projects, in particular, in a direction parallel to the direction X of the generatrices of the cylindrical base and / or in a direction parallel to the winding axis 14 relative to the active material of the first electrode of the electrochemical cell 12, towards the bottom of the cup-shaped first housing part 16. To promote the connection between the first housing part 16 and the first metal foil 22, the cup-shaped first housing part 16 can have indentations 26, for example in the form of beads as shown in the example.

[0035] As in the example shown, the second metal foil 24 can be connected to the second housing part 18, for example by welding. The second metal foil 24 projects, in particular, in a direction parallel to the direction X of the generatrices of the cylindrical base and / or in a direction parallel to the winding axis 14 relative to the active material of the second electrode of the electrochemical cell 12, towards the bottom of the cup-shaped second housing part 18. To facilitate the connection between the second housing part 18 and the second metal foil 24, the cup-shaped second housing part 18 can have indentations 26, for example in the form of beads as shown in the example.

[0036] As in the example shown, the first housing part 16 and the second housing part 18 can have contacts 28 for electrically contacting the cell 12. These can be formed, as in the example shown, as molded contours projecting outwards in a direction X parallel to the generatrix of the cylindrical base shape in the area of ​​the bottom of the respective housing part 16 or 18.

[0037] The first housing part 16 can be electrically insulated from the second housing part 18. This can be achieved, in particular, as in the example shown, by the third housing part 20. This third housing part can be designed, as shown by way of example, as a tubular injection-molded plastic part, at least substantially. The first housing part 16 and the second housing part 18 are made, in particular, of a metallic material.

[0038] As shown in the example, housing parts 16 and 18 can be slid onto the third housing part 20 and, in particular, bonded to it. The third housing part 20 can have an outwardly projecting area 30. As in the example shown, the outwardly projecting area 30 can surround the third housing part 20 in an annular manner. In the area of ​​the outwardly projecting area 30, the third housing part 20 can have a reinforcing element 32. The reinforcing element 32 can, for example, be overmolded with the third housing part 20, as in the example shown.

[0039] As in the example shown, the outwardly projecting area 30 can form a stop for the first housing part 16 and the second housing part 18. In other words, the housing parts 16 and 18 can abut the outwardly projecting area 30 with their respective open ends in a direction parallel to the direction X of the generatrix of the cylindrical base shape.

[0040] The third housing part 20 can further have a diffusion-retardant coating (not shown for illustrative reasons), such as a metallic coating, on an inwardly facing surface. A separator 34 of the electrochemical cell 12, arranged in the region of the cylindrical base surface, can extend along the metallic coating, as in the example shown, to such an extent that it forms an electrically insulating barrier between the metallic coating and the metallic components of the electrochemical cell 12 over the entire surface of the metallic coating. As in the example shown, the separator 34 can, in particular, extend at least over the entire inwardly facing surface of the third housing part 20.This advantageously allows for the full-surface coating of the inward-facing surface of the third housing part 20 with a diffusion-inhibiting metallic coating. In particular, if the separator 34, as shown by way of example, extends beyond the third housing part 20 to both ends of the battery cell 10 in a direction X parallel to the generatrix of the cylindrical base shape, the separator 34 can thus provide effective protection against potential short circuits.

[0041] The features of the invention disclosed in this description, in the drawings, and in the claims can be essential for realizing the invention in its various embodiments, both individually and in any combination. The invention is not limited to the described embodiments. It 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 cells 12 electrochemical cell 14 winding axis 16 first housing part 18 second housing part 20 third housing part 22 first metal foil 24 second metal foil 26 shapes 28 contacts 30 outwardly projecting area 32 Reinforcing element 34 Separator X direction of the generatrix QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2022 111 706 A1

[0002] DE 10 2022 111 707 A1

[0006]

Claims

[1] Battery cell (10) comprising a housing and an electrochemical cell (12) arranged within the housing, wherein the housing has a cylindrical basic shape corresponding to a general cylinder with a closed guide curve, comprising a base surface, a top surface parallel to the base surface and a lateral surface, wherein the housing comprises a cup-shaped first housing part (16) which is arranged in the area of ​​the base and a part of the lateral surface adjacent to the base, a cup-shaped second housing part (18) which is arranged in the area of ​​the top surface and a part of the lateral surface adjacent to the top surface, and a sleeve-shaped third housing part (20) which is arranged in the area of ​​at least a part of the lateral surface, wherein the first and second housing parts (16, 18) are connected by the third housing part (20). [2] Battery cell (10) according to claim 1,characterized by , that the battery cell (10) has a cylindrical basic shape corresponding to a vertical circular cylinder. [3] Battery cell (10) according to claim 1 or 2, characterized by , that the first housing part (16) is electrically insulated from the second housing part (18). [4] Battery cell (10) according to any of the preceding claims, characterized by , that the third housing part (20) is made of an electrically non-conductive material, in particular plastic. [5] Battery cell (10) according to any one of the preceding claims, characterized by , that the first housing part (16) and / or the second housing part (18) is made of a metallic material. [6] Battery cell (10) according to any one of the preceding claims, characterized by , that the first housing part (16) and / or the second housing part (18) is pushed onto the third housing part (20). [7] Battery cell (10) according to any of the preceding claims, characterized by, that the first housing part (16) and / or the second housing part (18) is glued to the third housing part (20). [8] Battery cell (10) according to any one of the preceding claims, characterized by , that the third housing part (20) has an outwardly projecting area (30) which surrounds the third housing part (20) in a ring-like manner. [9] Battery cell (10) according to claim 8, characterized by , that the third housing part (20), in particular in the area of ​​the outwardly projecting area (30), has a fiber reinforcement and / or a metallic reinforcing element (32). [10] Battery cell (10) according to claim 8 or 9, characterized by , that the outwardly projecting area (30) forms a stop for the first housing part (16) and / or the second housing part (18). [11] Battery cell (10) according to any one of the preceding claims, characterized by, that the third housing part (20) has a diffusion-inhibiting coating, in particular a metallic coating, on an inwardly facing surface. [12] Battery cell (10) according to claim 11, characterized by , that a separator (34) arranged in the area of ​​the cladding surface of the electrochemical cell (12) extends at least so far along the metallic coating that it forms an electrically insulating barrier between the metallic coating and the metallic components of the electrochemical cell (12) over the entire surface of the metallic coating. [13] Battery cell (10) according to any one of the preceding claims, characterized by, that a first metal foil (22) of a first electrode of the electrochemical cell (12) is electrically connected to the first housing part (16) and / or a second metal foil (24) of a second electrode of the electrochemical cell (12) is electrically connected to the second housing part (18), in particular wherein the connection between the first metal foil (22) and the first housing part (16) is arranged in the area of ​​the base surface of the cylindrical basic shape and / or the connection between the second metal foil (24) and the second housing part (18) is arranged in the area of ​​the top surface of the cylindrical basic shape.

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