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DE-102025113651-A1 - Single cell and electric battery

DE102025113651A1DE 102025113651 A1DE102025113651 A1DE 102025113651A1DE-102025113651-A1

Abstract

The invention relates to a single cell (100) for an electric battery (500), comprising a cell housing formed from two electrically insulated and interconnected housing parts (110, 120) and an electrode foil arrangement (5) arranged inside the cell housing, the electrical poles of which are each electrically connected to one of the two housing parts (110, 120), wherein the two housing parts (110, 120) are connected to each other by a crimp seam (150), and an electric battery (500) consisting of several such single cells (100).

Inventors

  • Christian Elsner
  • Michael BRANDNER

Assignees

  • Mercedes-Benz Group AG

Dates

Publication Date
20260513
Application Date
20250407

Claims (10)

  1. A single cell (100) for an electric battery (500), comprising: - a cell housing formed from two electrically insulated and interconnected housing parts (110, 120) and - an electrode foil arrangement (210) arranged within the cell housing, the electrical poles of which are each electrically connected to one of the two housing parts (110, 120), characterized in that: - the two housing parts (110, 120) are connected to each other by a crimp seam (150) and - the cell housing has an at least approximately prismatic basic shape with a substantially polygonal, in particular rectangular or square, base and top surface, or with a substantially oval base and top surface.
  2. Single cell (100) after Claim 1 , characterized in that a first housing part (110) is a cup- or trough-shaped sheet metal deep-drawn part and a second housing part (120) is a substantially flat sheet metal cover.
  3. Single cell (100) after Claim 1 or 2 , characterized in that at least one of the two housing parts (110, 120) is coated on at least one side with an insulating layer (130), and/or an insulating element (140) is arranged between the two housing parts (110, 120) in the area of the flanged seam (150).
  4. Single cell (100) after Claim 3 , characterized in that a thermoplastic insulating layer (130) or a thermoplastic insulating element (140) is partially melted by thermal treatment in the area of the flanged seam (150), and/or an adhesive-like insulating layer (130) or/and an adhesive-like and/or adhesive-coated insulating element (140) is cured.
  5. Single cell (100) according to one of the Claims 1 until 4 , characterized in that at least one of the two housing parts (110, 120) has a roughened or structured surface at least in the area of the flanged seam (150), and/or the flanged seam (150) is strengthened by re-pressing or flanging.
  6. Single cell (100) according to one of the Claims 1 until 5 , characterized in that at least one connecting element (300) for mechanical and/or electrical contacting of another single cell (100) is attached to at least one of the two housing parts (110, 120).
  7. Single cell (100) according to one of the Claims 1 until 6 , characterized in that at least one of the two housing parts (110, 120) has at least one reinforcement area in which the housing part (110, 120) has an increased wall thickness.
  8. Single cell (100) after Claim 7 , characterized in that the reinforcement area is formed by attaching a reinforcement element (320) to the housing part (110, 120).
  9. Single cell (100) according to one of the Claims 1 until 8 , characterized in that at least one of the two housing parts (110, 120) has a circumferential notch line as a predetermined breaking point.
  10. Electric battery (500), comprising a plurality of electrically parallel and/or series connected individual cells (100) according to one of the Claims 1 until 9 .

Description

The invention relates to a single cell for an electric battery according to the preamble of claim 1 and to an electric battery according to the preamble of claim 10. Current rechargeable batteries require considerable space for complex internal structures to transfer power from the electrode foils to an external terminal or casing wall, resulting in a lower charging capacity than they could be. They are difficult or impossible to open for recycling and are therefore often shredded whole. Conventional individual cells cannot be stacked securely to form battery blocks and thus require complex frame and stiffening structures to create rigid module blocks. Further problems with existing batteries include the need for retaining structures to apply preload and prevent cell thickness expansion. Different casings are required depending on whether the electrode foils are wound, Z-folded, or stacked. Typically, the individual cells have an additional rupture element for pressure relief in the event of a failure. Additional space is also needed to thread the cell stack into the casing. A basic principle in the design of current single cells is often the separation of the housing into two shells, so that the electrodes can be contacted directly on these two halves. DE 10 2008 010 814 A1 The patent discloses, for example, a single cell for a battery with an electrode stack arranged within a cell housing. The cell housing has two electrically conductive side walls and an electrically insulating frame arranged between them, with the electrode stack's pole contacts being electrically connected to the side walls. The side walls are fastened to the frame by means of interlocking and/or positive locking mechanisms. Parallel or series connection can be achieved, for example, by directly pressing cells together. A key challenge in the preliminary tests was ensuring a reliable seal against bursting up to approximately 10 bar. The then-unknown significant increase in cell thickness in lithium-ion cells and the associated need for compensating elements and pressing devices were not taken into account. Furthermore, a considerable amount of installation space is consumed by the retaining elements. Flanging as a connection method for closing cell casings is currently only used for cylindrical cells in the state of the art. Manufacturing is similar to that of beverage cans. A disadvantage of cylindrical cells is the lack of a way to secure the individual cells within a battery module, as a positive connection between the individual cells is not possible. Therefore, complex adhesive or foaming processes are used. Furthermore, filling the individual cells with the electrode winding requires very high precision and a gap, as contact during winding insertion can lead to damage or short circuits. Opening cylindrical cells is difficult with regard to recycling, as there is very little space between the casing wall and the electrode winding. The invention is based on the objective of providing a single cell that is simple and inexpensive to manufacture and can be arranged in a space-saving manner in an electric battery. A further objective is to provide a pressure-resistant single cell. A still further objective is to provide a recyclable single cell. The problem is solved according to the invention by a single cell having the features of the characterizing part of claim 1 and by an electric battery having the features of the characterizing part of claim 10. Advantageous embodiments of the invention are the subject of the dependent claims. A single cell according to the invention for an electric battery comprises a cell housing formed from two electrically insulated and interconnected housing parts and an electrode foil arrangement arranged inside the cell housing, the electrical poles of which are each electrically connected to one of the two housing parts, wherein the two housing parts are connected to each other by a crimp seam and the cell housing has an at least approximately prismatic basic shape with a substantially polygonal, in particular rectangular or square, base and top surface, or with a substantially oval base and top surface. According to the invention, the construction of the cell housing resembles the cans known per se, such as those used for canned fish and other preserves. Such cell housings can advantageously be stackable, meaning that their contact surfaces can be designed to interlock, thus facilitating the formation of self-supporting cell stacks or modules, as will be shown below with regard to specific embodiments. This will be explained in more detail later. The pressure-tight sealing of the cell housings by means of crimping is a proven technology. However, a special feature of the single cell proposed according to the invention is that the outer shape of the housing parts does not correspond to a cylinder as with round cells, but has an essentially prismatic basic shape and is, for example, rectangular, square, o