Cell housing for holding a battery cell body or battery cell

Abstract

A cell housing (10) for receiving a battery cell body or for receiving at least one battery cell, with a closed, circumferential, frame-like perimeter wall (12) made of a flat material. The perimeter wall (12) is formed in one piece and has an overlapping section (22) in which a starting section (24) of the perimeter wall (12) and a ending section (26) of the perimeter wall (12) overlap. The starting section (24) and the ending section (26) are attached to each other. A bursting element (28) is provided in the starting section (24) or in the ending section (26), and a recess (32) opposite the bursting element (28) is provided in the other of the two sections (24, 26).

Description

[0001] The present invention relates to a cell housing for accommodating a battery cell body or for accommodating at least one battery cell, a battery with a cell housing and a method for producing a cell housing.

[0002] Battery cells, also called accumulator cells, are used to chemically store electrically supplied energy. One of the most well-known battery cells is the lithium-ion battery cell.

[0003] Typically, a battery cell comprises at least one battery cell body in the form of an electrode coil or an electrode stack, which in turn is formed from at least one positive electrode, at least one negative electrode, and at least one separator arranged between the positive and negative electrodes. The battery cell body can additionally have an insulating foil wound around the electrode coil or electrode stack. To form a battery cell, the battery cell body is inserted into a housing. Depending on the design of the housing, the battery cell is designed as a round cell, a pouch cell, or a prismatic cell.

[0004] A battery, on the other hand, is usually a battery module consisting of several individual battery cells, i.e. battery cell bodies with housings, which are housed together in a housing.

[0005] In certain situations, such as a defect or improper handling, lithium-ion battery cells or batteries can lead to gas formation and overpressure within the battery cell or battery. Therefore, it is known to provide a pressure relief valve or bursting membrane in the cell casing of the battery cell or battery to specifically vent the resulting gases in one direction and prevent thermal runaway of the battery cell.

[0006] If a bursting element is inserted into the cell casing, it may be necessary to increase the wall thickness on the side in which the bursting element is inserted to ensure that the rigidity of that side is maintained despite the bursting element. For manufacturing reasons, this typically involves increasing the wall thickness of the entire cell casing, which, however, results in high material consumption and a larger space requirement, or a reduced capacity of the battery cell body.

[0007] The object of the present invention is therefore to provide an improved cell housing, an improved battery with a cell housing and a method for producing a cell housing.

[0008] The object is achieved according to the invention by a cell housing for accommodating a battery cell body or for accommodating at least one battery cell, having a closed, circumferential, frame-like peripheral wall. The peripheral wall is formed in one piece and has an overlap section in which a starting section of the peripheral wall and an end section of the peripheral wall overlap and are fastened to one another. A bursting element is provided in the starting section or the end section of the peripheral wall, and a recess opposite the bursting element is provided in the other of the two sections.

[0009] The basic idea of ​​the invention is based on the fact that in a metallic cell housing produced by a bending, pressing, welding, or roll-forming process and having a bursting element as a safety element, the wall thickness of the entire cell housing does not have to be increased. Instead, by introducing an overlapping section, one-sided stiffening of the cell housing is achieved, giving the cell housing sufficient stability. The overlapping section thus has a one-sided stiffening effect. This allows material to be saved during production of the cell housing, and the cell housing is sufficiently stable despite the bursting element. If the cell housing is designed to enclose several battery cells, it can accommodate more battery cells overall with the same external dimensions.

[0010] According to the invention, the battery cell body represents the inner workings of a battery cell and consists of at least one oppositely arranged pair of anode and cathode, which are separated from each other by a separator. The battery cell body preferably consists of several layers of anode, separator, and cathode, which are manufactured using either stacking technology or wound technology. The battery cell body can additionally contain an insulating foil that completely encloses the electrode stack to prevent direct contact between the electrode stack and the cell casing, thus preventing a short circuit between the electrodes and the metallic casing.

[0011] A battery cell comprises the battery cell body and the surrounding casing, which is then welded to a lid and base and then filled with an electrolyte. In this case, the casing forms the cell housing and completely encloses the battery cell body with its closed peripheral wall, like a frame.

[0012] The cell housing according to the invention can also accommodate one or more finished battery cells (with their individual housings). Depending on what the cell housing is intended to accommodate, the cell housing has different dimensions. However, the cell housing preferably serves only to accommodate a single battery cell body with one or more anodes, cathodes, and separators, and optionally an insulating foil.

[0013] To prevent an uncontrolled explosion of the battery cell or battery in the event of a burst, in which the internal pressure in the cell casing exceeds a predetermined limit, and instead divert the pressure in a targeted direction, the peripheral wall of the cell casing features a bursting element that serves as a safety element in the event of an increase in internal pressure. The bursting element represents a predetermined breaking point in the otherwise closed cell casing. The bursting element is designed to burst only at a desired internal cell pressure, but not at an excessively low or excessively high internal cell pressure.

[0014] The recess in the overlap section opposite the bursting element serves to weaken the cell casing, which is stiffened in the overlap section, only in the area of ​​the bursting element and to remove the stiffening there so that in the event of a burst, the bursting element can burst and pressure equalization can take place.

[0015] The recess is preferably at least as large as the bursting element itself, so that the bursting element is always completely located within the recess. This prevents damage to the cell casing around the bursting element in the event of a burst and, in the worst case, splintering of the cell casing.

[0016] According to the invention, the overlapping initial and end sections in the overlapping section are joined together in a materially bonded manner. Joining methods such as laser welding, friction stir welding, or soldering are particularly suitable for this purpose. The two sections can be attached to each other either by welding through a side of the cell casing adjacent to the section or via a fillet weld. The double or multiple walls in the area of ​​the edge of the recess stiffen the cell casing in this edge area, which improves the targeted opening process.

[0017] According to the invention, the cell housing is formed from a formed flat material, for example, made of aluminum or steel, with a constant wall thickness. The wall thickness of the peripheral wall is therefore also fundamentally constant, with the exception of any weakened zones in the area of ​​the bursting element and the recess. There, the wall thickness can be thinner in some sections than the wall thickness of the flat material and thus than the wall thickness of the peripheral wall. The wall thickness of the peripheral wall is, in particular, between 0.2 mm and 3 mm. A wall thickness in this range enables a stable cell housing that can withstand high internal pressure without consuming too much material during production.

[0018] According to one aspect of the invention, the cell housing has a wall thickness in the overlap section outside the recess that is greater than the wall thickness of the peripheral wall outside the overlap section. The recess and optionally also the bursting element reduce the wall thickness in these areas of the overlap section. In the remaining areas of the overlap section, i.e. where neither the bursting element nor the recess are provided, the wall thickness of the cell housing is greater than the wall thickness of the single peripheral wall, since the peripheral wall is present twice there. Multiple overlaps of the peripheral wall in the overlap section are of course also possible. The overlap leads to one-sided stiffening of the peripheral wall in the overlap section. The weakening of the cell housing can thus be compensated for by inserting a bursting element and a recess.In particular, the wall thickness in the areas of the overlap section where neither a bursting element nor a recess is installed is twice or several times the wall thickness of the single peripheral wall. This is because the wall thickness in the initial and final sections corresponds to the wall thickness of the peripheral wall, and the overlap of the initial and final sections results in a doubling or, in the case of multiple overlaps, a multiplication of the wall thickness in the areas of the overlap section where no bursting element and no recess are installed. Thus, if the wall thickness is doubled in these areas, it is between 0.4 mm and 6 mm; if the wall thickness is doubled, it is a correspondingly multiple of this.

[0019] According to the invention, the peripheral wall of the cell housing has a polygonal cross-section, in particular a rectangular cross-section, with two short sides and two long sides.

[0020] The overlapping section is preferably arranged only on one short side or one long side. In particular, the rectangular cross-section of the cell housing makes it particularly well-suited for accommodating prismatic battery cell bodies. In principle, however, it is also possible for the cell housing to have a different polygonal cross-section in order to accommodate other battery cell body shapes. A rectangular cross-section is preferred, however, because the prismatic battery cell bodies or battery cells accommodated therein, for example, exhibit better heat dissipation than cylindrical cells.

[0021] With a rectangular cross-section, the peripheral wall has at least four bending edges. Each bending edge has a bending radius between 0.2 mm and 10 mm. Depending on the bending radius, the peripheral wall is subjected to greater or lesser stress in the bending areas. A large bending radius results in less material stress on the peripheral wall in the bending area than a smaller bending radius. Conversely, a large bending radius reduces the volume inside the cell housing that can accommodate a battery cell body or a battery cell. If the peripheral wall has more than four bending edges, the cell housing either no longer has a polygonal cross-section or the overlap section extends over two sides of the cell housing. With more than four bending edges, a multiple overlap of the peripheral wall in the overlap section can also be achieved.

[0022] Regardless of the number of bending edges of the cell casing, the short sides and the adjacent long sides of a rectangular cell casing cross-section form a bending angle that is essentially 90°. The 90° bending angle creates a rectangular cross-section of the cell casing, which is particularly suitable for accommodating prismatic battery cell bodies.

[0023] According to the invention, the overlap section of the cell housing forms at least 90% of the area of ​​one side and / or the recess is laterally spaced away from the edge of the overlap section on all sides. In order to achieve sufficient support and stiffening of the cell housing, either the side of the cell housing that has the overlap section consists almost exclusively of the overlap section and has almost exclusively a wall thickness twice or several times that of the overlap section, or the recess is spaced apart from the edge of the overlap section. Both variants ensure sufficiently great stiffening of the side. If the highest possible stiffening of the side is to be achieved, a particularly large overlap section and a recess that does not contact the edge of the overlap section can also be combined.This also ensures that the recess is sufficiently supported by the overlapping section, so that the side has a particularly high level of rigidity and the recess does not represent an additional weak point or even a predetermined breaking point.

[0024] According to a further aspect of the invention, the bursting element is an additional component attached to the peripheral wall. In particular, the bursting element is attached to the peripheral wall in a material-to-material manner, for example, by laser welding. Attaching the bursting element to the peripheral wall in a material-to-material manner ensures that the attachment points where the bursting element contacts the peripheral wall do not represent additional predetermined breaking points that could burst in the event of a burst, allowing the gas inside the cell body to escape uncontrollably. If the bursting element is designed as a separate component, it can be, for example, a bursting membrane or a bursting disc.

[0025] Alternatively, the bursting element can be formed as a section of the peripheral wall, merging integrally with the rest of the peripheral wall and featuring a weakened zone. In this case, the bursting element is part of the peripheral wall and is incorporated directly into the material of the peripheral wall, for example, milled. In this case, the bursting element has a weakened zone in which the material of the peripheral wall is further weakened, for example, by the milling. In the event of a burst, the peripheral wall then bursts precisely in the weakened zone, allowing the gas to escape in a targeted manner.

[0026] The weakened zone can run adjacent to the edge of the recess or it can run transversely through the recess. The course of the weakened zone depends on several factors. Firstly, the overall size of the weakened zone is crucial to provide an opening large enough to dissipate the pressure generated in the cell casing as quickly as possible in the event of a burst, without, for example, the battery cell body passing through the opening. Secondly, the course of the weakened zone also depends on the size of the cell casing and the maximum possible size of the recess.

[0027] The recess should be larger than the bursting element. In other words, the weakened zone should always be completely within the recess to ensure successful bursting without damaging the cell casing at any other unwanted location.

[0028] According to the invention, the weakening zone of the bursting element is a recess on the inside and / or outside of the cell casing. In particular, the recess has a wedge-shaped or trapezoidal cross-section with optional rounding. The weakening zone can be located either on the inside or outside of the cell casing. It is also possible for the weakening zone to be located on both sides.

[0029] In the event of a burst, the bursting element has an opening area of ​​20 to 5,000 mm 2 The opening pressure, i.e., the pressure that must prevail inside the cell casing for the bursting element to burst, is between 2 and 30 bar. The size of the opening area depends on the size of the bursting element. The opening pressure can be adjusted and adjusted, for example, by changing the dimensions of the bursting element's recess or by installing a specific bursting element.

[0030] According to a further aspect of the invention, the cell housing is closed at the front by a base coupled to the peripheral wall and an opposite cover. The connection between the base or cover and the housing wall is a material fit, so that neither the electrolyte solution filled into the housing can leak through the weld seam, nor can other substances penetrate into the battery cell via the weld seam.

[0031] Both the base and the lid can contain the two poles required for a battery. Either the lid can contain both poles, or one pole is located in the lid and a second pole in the base.

[0032] The above-mentioned object is also achieved by a battery with a cell housing as described above and one or more battery cell bodies housed therein, or one or more battery cells housed therein, each equipped with its own housing. The battery cells are preferably prismatic battery cells. In addition to the cell housing and the battery cell body or the battery cells, the battery also has the base, the lid, and an electrolyte solution as described above.

[0033] According to the invention, a four-stage process for producing the cell housing is also provided.

[0034] In a first step, a flat plate made of flat material is prepared. The plate can be made of any metal material, but is preferably made of aluminum or sheet steel.

[0035] In a second step, a bursting element is provided either at a starting section or at an end section of the plate. In particular, a bursting element is attached if the bursting element is a separate component, or it is inserted if the bursting element is formed as part of the plate. Then, a recess opposite the bursting element in an assembled state is formed in the other of the two sections.

[0036] In a third step, the plate is formed into the closed, frame-like peripheral wall. The plate is formed in at least four places, creating at least four bending edges. The initial and final sections of the peripheral wall overlap at least partially, forming the overlap section. The plate can be bent, roll-formed, extruded, or stack-pressed. However, it is typically bent or produced as a continuous tube by tube forming, as these processes facilitate the subsequent insertion of the bursting element.

[0037] In a fourth step, the initial section and the end section in the overlapping section are at least partially joined together using a joining process. Possible joining methods include laser welding or friction stir welding, creating a fillet weld. If the initial section and the end section overlap to such an extent that one of the two sections contacts a second side wall, this section can be attached to the adjacent housing side by penetration welding. The connection can also be made across the entire overlap area, for example, by soldering.

[0038] Of course, it is also possible to insert the bursting element and the recess opposite the bursting element after forming the cell casing and connecting the initial section and the end section.

[0039] It is advantageous for the bursting element to be located entirely within the recess. The bursting element can either be embedded directly into the material or attached as a separate bursting element to the peripheral wall, for example, by laser welding. The bursting element can be provided either on the inner or outer layer of the peripheral wall. Depending on which layer the bursting element is formed on, the other layer of the peripheral wall has the opposite recess in the overlap area.

[0040] To produce a finished battery, after the cell casing has been manufactured, the battery cell body is inserted into the cell casing. A base and a lid seal the cell casing, for example, by laser or ultrasonic welding. An electrolyte solution is introduced before or after this process. Alternatively, one or more finished battery cells can be inserted into the cell casing. In this case, a base and a lid are attached to the peripheral wall to complete the battery and seal the cell casing.

[0041] Further features and advantages of the invention will become apparent from the following description and the accompanying drawings, to which reference is made. In the drawings: - Fig. 1 a schematic cross-section of a cell housing according to the invention before the introduction of a bursting element and a recess; - Fig. 2 a schematic cross-section of a part of a cell housing according to the invention with several bending edges before the insertion of a bursting element and a recess; - Fig. 3 a schematic perspective view of a cell housing according to the invention with a bursting element and a recess; - Fig. 4 a schematic cross-section of the upper part of the cell housing Fig. 3; - Fig. 5 a schematic representation of the method according to the invention for producing the cell housing from Fig. 3.

[0042] The Fig. 1 to 4 show a cell housing 10, more precisely a section of a cell housing 10, which is suitable for receiving a singular battery cell body (6) or for receiving several battery cells (8).

[0043] The cell housing 10, or more precisely the peripheral wall 12 shown, is made of a formed flat material. In principle, any common metal material can be used as the flat material, for example, aluminum or steel.

[0044] The peripheral wall 12 is made in one piece from the flat material by forming, in particular bending or roll forming.

[0045] The peripheral wall is circumferentially closed and frame-like, enclosing a cavity 14. A battery cell body 6 or several battery cells 8 can be inserted into this cavity 14 at a later time.

[0046] The cell casing 10 has a rectangular cross-section with two short, opposite sides 16 and two long, opposite sides 18, each of which runs parallel to each other. The two sides 16 and 18 can have any length, as long as the two short sides 16 and the two long sides 18 are each substantially the same length.

[0047] Between two adjacent sides 16, 18, there is a bending edge 20 with a bending radius r between 0.2 mm and 10 mm. To prevent unnecessary material stress, the bending edge 20 is not a sharp edge, but a blunt edge.

[0048] The short sides 16 and the adjacent long sides 18 enclose a bending angle α of essentially 90° in a rectangular cross-section.

[0049] Parts of the peripheral wall 12 overlap on one of the two short sides 16, forming an area in which the peripheral wall is reinforced on one side. This area represents an overlap section 22.

[0050] Strictly speaking, the overlap section 22 is formed from a starting section 24 and an end section 26 of the peripheral wall 12.

[0051] The initial section 24 is arranged on the side of the cell housing 10 facing away from the cavity 14 and forms the outer layer and the end section is located on the side of the cell housing 10 facing the cavity 14 and forms the inner layer.

[0052] The entire overlap section 22 accounts for more than 90% of the area of ​​the short side 16. Thus, almost the entire short side 16 is stiffened by the overlap section 22.

[0053] In the cell housing 10, which is in Fig. 2, the end section 26 even extends beyond the short side 16 and contacts the adjacent long side 18.

[0054] In order to provide the cell housing 10 with the necessary stability, the initial section 24 and the end section 26 are firmly connected to one another at at least two fastening points (27). For this purpose, the two sections 24 and 26 are, for example, laser welded or friction stir welded. The resulting weld seam is, for example, designed as a fillet weld. If the end section 26 is longer than the short side 16 or the long side 18 and contacts the adjacent side 16, 18, the end section 26 can also be fastened to a short side 16 or long side 18, for example, by through-welding, as shown in Fig. 2 is shown.

[0055] The peripheral wall 12 is formed from a flat material having a constant wall thickness w1. Since the peripheral wall is formed integrally from the flat material, the cell housing 10 also has the constant wall thickness w1 in most areas. Only in the overlapping section 22 does the cell housing 10 have a different wall thickness w2. By overlapping the starting section 24 and the end section 26 of the cell housing in the Fig. 1 and Fig. 2, the wall thickness w2 in the overlap section 22 is twice as large as the wall thickness w1. This leads to one-sided reinforcement and stiffening of the cell casing 10.

[0056] This stiffening is required because, for safety reasons, as described in the Fig. 3 and Fig. 4, a bursting element 28 is provided in the overlapping section 22 of the cell housing 10, either in the initial section 24 or in the end section 26, which bursts in the event of a burst, so that the excess pressure created inside the cell housing 10 can be equalized.

[0057] The bursting element 28 can either be formed as a section of the peripheral wall and merge integrally into the rest of the peripheral wall 12 or it can be formed as a separate element which is firmly attached to the peripheral wall 12.

[0058] The Fig. 3 and Fig. The bursting element 28 shown in Figure 4 is formed as part of the peripheral wall 12. The bursting element 28 has a weakened zone 30, which represents the predetermined breaking point of the bursting element 28.

[0059] This weakened zone 30 enables the bursting element 28 to burst if the pressure inside the cell housing 10 exceeds a predefined limit. The opening pressure required for the bursting element 28 to burst at the weakened zone 30 is between 2 and 30 bar. In such a bursting event, the cell housing 10 has an opening area of ​​between 20 and 5,000 mm 2 depending on the size of the bursting element 28 and the weakening zone 30.

[0060] In the Fig. 4 shows a weakened zone 30, which is designed as a notch and has a wedge-shaped cross-section. The weakened zone 30 is located in the end section 26 of the peripheral wall 12 and is on the side of the end section 26 facing away from the cavity 14.

[0061] Of course, the weakened zone 30 can also be arranged on the side of the end section 26 facing the cavity 14. Two weakened zones 30 are also possible, with one weakened zone 30 being arranged on the side of the end section 26 facing away from the cavity 14 and the second weakened zone 30 being arranged on the side of the end section 26 facing the cavity 14. A weakened zone 30 that is part of the initial section 24 is also possible.

[0062] If the bursting element 28 is designed as a separate component, it is firmly bonded to the peripheral wall 12. A firmly bonded connection can be achieved, for example, by laser welding. The bursting element 28 can be, for example, a bursting membrane or a bursting disc.

[0063] The section 24, 26 which does not have a bursting element 28 has a recess 32 opposite the bursting element 28 so that the cell housing is not reinforced in the area of ​​the bursting element 28 and can be opened.

[0064] The recess 32 is shaped such that the bursting element 28 lies completely within the recess 32, so that the recess 32 completely encloses the bursting element 28.

[0065] As in the Fig. 3 and Fig. 4, the recess 32 has an oval-shaped outer edge 34. However, the outer edge 34 of the recess 32 can have any geometric shape as long as it completely encloses the bursting element 28.

[0066] Furthermore, the recess 32 is laterally spaced from an edge 36 of the peripheral wall 12 on all sides. The recess 32 is thus completely enclosed by the initial section 24 and thus by the peripheral wall 12.

[0067] The entire outer edge 34 of the recess 32 and the remaining part of the initial section 24 contact the underlying end section 26 of the peripheral wall 12 with the bursting element 28, so that the entire part of the initial section 24 is supported circumferentially from all sides by the end section 26, starting from the outer edge 34 of the recess 32.

[0068] The weakening zone 30 of the bursting element 28 can either run adjacent to the outer edge 34 of the recess 32 or the weakening zone 30 runs transversely to the recess 32.

[0069] In Fig. 3 shows a weakening zone 30 of the bursting element 28, which runs centrally in the recess 32.

[0070] Both the weakened zone 30 of the bursting element 28 and the recess 32 form only a small part of the overlap section, so that the side does not lose too much rigidity due to the bursting element 28 and the recess 32 and the recess 32 is still well supported on all sides.

[0071] By inserting the recess 32 and the bursting element 28 into the overlap section 22, the cell housing 10 has a smaller wall thickness w2 in this area than in the remaining overlap section 22. If the bursting element 28 is a notch, the wall thickness w2 in this area is even smaller than the wall thickness w1. It is therefore all the more important that the side in which the recess 32 and the bursting element 28 are located is stiffened by the overlap section 22.

[0072] Fig.5 shows a four-step process for producing the cell housing 10. In a first step S1, a flat plate made of flat material is provided.

[0073] In a second step S2, a bursting element 28 is inserted into or attached to either the initial section 24 or the end section 26. A recess 32 is formed on the other of the two sections 24, 26, opposite the bursting element in the assembled cell housing, so that the bursting element 28, in the assembled state, is arranged within the recess 32, as viewed in plan view.

[0074] This flat plate is formed in a third step S3 to create a closed, circumferential, frame-like peripheral wall 12. This peripheral wall 12 is formed integrally from the plate. Various methods for mechanically forming metals can be used to form the plate, such as impact extrusion, extrusion, bending, or roll forming. The bending angle α when bending the plate is essentially 90°. In total, the plate is bent at least four times to create four or more bending edges 20. The bending radius r of each bending edge 20 is between 0.2 mm and 10 mm. The plate is bent such that the starting section 24 and the end section 26 of the peripheral wall 12 overlap in the overlap section 22, thus achieving one-sided stiffening of the cell housing 10. This results in a wall thickness w2 in the overlap section 22 that is twice as large as the wall thickness w1 of the remaining cell housing 10.

[0075] In a fourth step S4, the initial section 24 and the end section 26 are at least partially joined together in the overlapping section 22 in order to ensure the stability of the cell housing 10. Laser welding, friction stir welding, or similar welding or soldering methods are particularly suitable for this purpose. The area in which the initial section 24 and the end section 26 are joined together represents a fastening point, which is achieved either by through-welding from an adjacent side or is formed as a fillet weld. The weld can be either point-shaped or flat.

[0076] After the cell casing 10 has been manufactured, it can accommodate either a battery cell body 6 or one or more finished battery cells 8 in its cavity 14 and form a battery.

[0077] To manufacture the battery cell, after attaching the base to the cell housing 10, the battery cell body 6, consisting of an electrode stack and an insulator foil, is inserted into the cell housing 10, and the cover is welded to the cell housing so that both the base and the cover are subsequently positively coupled to the peripheral wall 12. An electrolyte solution is then introduced.

[0078] To produce a more powerful battery, multiple battery cells 8 with their own housing can be inserted into the cell housing 10. The resulting battery then consists of several individual battery cells 8, all of which are inserted into the cell housing 10 and connected to one another. These are preferably prismatic battery cells 8, which have improved heat dissipation.

[0079] The cell housing 10 thus serves both to accommodate individual battery cell bodies and to accommodate entire battery cells in order to form a battery consisting of only one battery cell body with a cell housing 10 or several battery cell bodies with a housing.

Claims

[1] Cell housing (10) for receiving a battery cell body (6) or for receiving at least one battery cell (8), with a closed, circumferential, frame-like circumferential wall (12) made of a flat material, wherein the circumferential wall (12) is formed in one piece and has an overlapping section (22) in which a starting section (24) of the circumferential wall (12) and an end section (26) of the circumferential wall (12) overlap and are fastened to one another, and wherein a bursting element (28) is provided in the starting section (24) or in the end section (26) and a recess (32) opposite the bursting element (28) is provided in the other of the two sections (24, 26). [2] Cell housing (10) according to claim 1, characterized by that the cell housing (10) is formed by a formed flat material with a constant wall thickness w1. [3] Cell housing (10) according to claim 1 or 2, characterized bythat the cell housing (10) in the overlap section (22) outside the recess (32) has a wall thickness w2 which is greater than the wall thickness w1 of the peripheral wall (12) outside the overlap section (22). [4] Cell housing (10) according to one of the preceding claims, characterized by that the peripheral wall (12) has a polygonal cross-section, in particular a rectangular cross-section, with two short sides (16) and two long sides (18), preferably wherein the overlapping section (22) is arranged only on one short side (16) or one long side (18). [5] Cell housing (10) according to claim 4, characterized by that the short sides (16) and the adjacent long sides (18) enclose a bending angle α which is substantially 90°. [6] Cell housing (10) according to claim 4 or 5, characterized bythat the overlapping section (22) forms at least 90% of the area of one side (16, 18) and / or that the recess (32) is laterally spaced from the edge (36) of the overlapping section (22) on all sides. [7] Cell housing (10) according to one of the preceding claims, characterized by that the bursting element (28) forms an additional component and is attached to the peripheral wall (12), in particular in a materially bonded manner. [8] Cell housing (10) according to one of claims 1 to 6, characterized by that the bursting element (28) forms a section of the peripheral wall (12) and merges integrally into the remainder of the peripheral wall (12) and has a weakening zone (30). [9] Cell housing (10) according to claim 8, characterized by that the weakened zone (30) runs adjacent to the outer edge (34) of the recess (32) or transversely through the recess (32). [10] Cell housing (10) according to claim 8 or 9, characterized bythat the weakening zone (30) is an inside and / or outside depression with respect to the cell housing (10). [11] Cell housing (10) according to one of the preceding claims, characterized by that the bursting element (28) in a bursting state has an opening area of 20 to 5000 mm 2 and / or has an opening pressure between 2 and 30 bar. [12] Cell housing (10) according to one of the preceding claims, characterized by that the cell housing (10) is closed at the front by a base coupled to the peripheral wall (12) and an opposite cover. [13] Battery with a cell housing (10) according to one of the preceding claims and one or more battery cell bodies accommodated therein or one or more battery cells accommodated therein, each equipped with its own housing. [14] A method for producing a cell housing (10) according to any one of the preceding claims, the method comprising the following steps: a) Providing a flat plate; b) providing a bursting element (28) either at a starting section (24) or at an end section (26) and forming a recess (32) opposite the bursting element (28) in the other of the two sections (24, 26); c) forming the plate into a closed, circumferential, frame-like peripheral wall (12), wherein the initial section (24) and the end section (26) of the peripheral wall (12) at least partially overlap and form an overlap section (22); and d) at least partially connecting the initial section (24) and the end section (26) in the overlap section (22) using a material-to-material joining process.

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