Battery cell

Abstract

The invention relates to a battery cell (14) having a cell housing (26) in which a plurality of electrodes (20) are arranged. The cell housing (26) has a wall (28) with a desired fracture region (30), the desired fracture region (30) comprising an opening (32) which is covered by means of a gas-permeable membrane (36). A recess (38) extending up to the opening (32) is introduced into the wall (28) in a desired fracture region (30).

Description

Technical Field

[0001] The present invention relates to a battery cell (Batteriezelle, sometimes referred to as a battery cell). The battery cell has a cell housing in which a plurality of electrodes are arranged. Background Art

[0002] Motor vehicles (Kraftfahrzeug, sometimes called motor vehicles) are increasingly driven at least partially by means of electric motors, so that the motor vehicles are designed as electric vehicles or hybrid vehicles. For powering the electric motors, high-voltage batteries are usually used, which include a plurality of individual battery modules. The battery modules are usually structurally identical to one another and are electrically connected in series and / or in parallel with one another, so that the voltage present at the high-voltage battery corresponds to a multiple of the voltage provided by means of each of the battery modules. Each battery module in turn includes a plurality of battery cells, which are usually arranged in a common module housing and which are electrically connected in series and / or in parallel with one another.

[0003] Each of the battery cells then usually includes a plurality of current elements (galvanische Elemente). The current elements each have two electrodes (i.e., an anode and a cathode) and a separator (separator, sometimes called a separator) arranged between them and an electrolyte with freely movable charge carriers. As such an electrolyte, for example, a liquid is used. In an alternative, the battery cell is designed as a solid-state battery and the electrolyte is present as a solid. The anode and cathode forming the electrodes of the battery cell usually include a carrier (Stromableiter, sometimes called a current conductor) that acts as a current conductor. The substrate is usually fastened to the carrier, which is a component of a coating applied to the carrier, which is also called a conductor (ableiter, sometimes called a conductor). It is possible for the electrolyte to already be present in the coating or to be introduced later. However, the active material is at least suitable for absorbing working ions, such as lithium ions. Depending on the use as an anode or cathode, different materials for the carrier and different types of materials for the coating are used.

[0004] In order to protect the current element, it is usually arranged in a cell housing of the battery cell, which is also called a cell cup. The cell housing also protects the electrolyte from the surrounding environment. In order to provide a relatively large capacity with the help of the individual battery cells, a plurality of such current elements, usually up to 100, are usually arranged in a common cell housing. In order to use the existing space relatively efficiently and simplify production, the individual components of the current element are designed to be flat and are stacked one on top of the other in the stacking direction, so that a substantially rectangular block is formed. Single cell stack. In an alternative embodiment, for example, the separator is designed in the form of a strip and a plurality of electrodes are provided on opposite sides. The strip is wound into a coil, in particular into a so-called "jelly roll (JellyRoll, sometimes called Swiss roll)". Thus, the current element is rolled into a cylindrical shape.

[0005] The cell housing is shaped depending on the arrangement of the current element used. It is therefore possible to design the cell housing rigidly and to produce it, for example, from aluminum. The shape of the cell housing is, for example, rectangular. Such battery cells are also referred to as prismatic (sometimes referred to as uniform cross-section) cells. In an alternative embodiment, the cell housing is produced with the aid of a sheet that is laid around the current element. Such battery cells are also referred to as soft pack cells.

[0006] During the operation of the battery cells, i.e. during charging and also during discharging, it is possible that gases are generated due to undesired chemical reactions. Due to the gases, the pressure in the cell housing increases, so that on the one hand, the individual electrodes can be disconnected, which leads to power losses in the battery cell. On the other hand, it is possible that the cell housing deforms due to the increased pressure, so that in particular the surroundings of the battery cell are mechanically influenced. At relatively high pressures, the cell housing ruptures, so that the electrolyte can escape and the entire battery cell is no longer readily usable. It is also possible that undesired chemical reactions of individual components of the battery cell with the surroundings occur.

[0007] In order to avoid this gas formation, a special selection of the individual materials of the electrodes is required, which on the one hand increases the manufacturing costs. On the other hand, the capacity of the battery cell is reduced in the case of such materials. As an alternative to this, for example, additional elements are present in the cell housing, with the aid of which the generated gases are combined and / or converted. In another variant, the cell housing is designed to be relatively robust, so that when the battery cell is in operation, the pressure that causes the cell housing to rupture is never reached. However, due to the robust design of the additional elements or the cell housing, the structural space and also the weight of the battery cell are increased, which is why the energy density is reduced. Summary of the invention

[0008] The object of the present invention is to specify a particularly suitable battery cell, in which the operational reliability and / or the energy density are advantageously increased, and in which the production costs are expediently reduced.

[0009] This object is achieved according to the invention by the features of claim 1. Advantageous developments and embodiments are the subject matter of the dependent claims.

[0010] The battery cell is designed in particular to be rechargeable and is preferably a secondary battery. Preferably, the battery cell is a component of a motor vehicle in a specified state. The battery cell is suitable for this, in particular, is arranged and set up for this. In a specified state, the battery cell is, for example, a component of an energy storage device of a motor vehicle, which has a plurality of such battery cells. The battery cell is preferably divided into a plurality of battery modules, which are then structurally identical to each other. The battery cells are arranged in particular in the housing of the energy storage device or the respective battery module and are electrically connected to each other in parallel and / or in series. Therefore, the voltage present at the energy storage device / battery module is a multiple of the voltage provided by means of each of the battery cells. All battery cells are preferably structurally identical to each other here, which simplifies production.

[0011] The housing of the energy storage device or the respective battery module (which therefore in particular forms a composite of such a battery cell) is preferably produced from metal, for example steel (such as stainless steel) or an aluminum alloy. For production, for example, a die-casting method, a deep-drawing method, a casting die or an extrusion molding method are used. In particular, the housing of the energy storage device or the respective battery module is designed to be closed. Suitably, an interface is introduced into the housing of the energy storage device or the respective battery module, which interface forms the connection of the energy storage device / battery module. The interface is electrically contacted with the battery cell, so that if a corresponding plug is plugged into the connection, it is possible to feed electrical energy from the outside of the energy storage device and / or to remove electrical energy from the battery cell.

[0012] The motor vehicle is preferably connected to land and preferably has a plurality of wheels, at least one of which, preferably a plurality of or all wheels are driven by means of a drive. In particular, one of the wheels, preferably a plurality of them, is designed to be controllable. It is thus possible to move the motor vehicle independently of a certain road (e.g., a track, etc.). It is expediently possible here to position the motor vehicle essentially arbitrarily on a road, in particular, produced from asphalt, tar or concrete. The motor vehicle is, for example, a commercial vehicle, such as a truck (Lkw) or a bus. However, it is particularly preferred that the motor vehicle is a car (Pkw). Alternatively, the motor vehicle is, for example, a ship, an airplane, a helicopter, a multi-rotor aircraft, a bicycle (electric bicycle) or a motorcycle.

[0013] Suitably, the forward movement of the motor vehicle is achieved by means of a drive. For example, the drive, in particular the main drive, is at least partially designed to be electric, and the motor vehicle is, for example, an electric vehicle. The electric motor is operated, for example, by means of an energy storage device, which is appropriately designed as a high-volt battery. Suitably, a DC voltage is provided by means of a high-volt battery, wherein the voltage is, for example, between 200V and 800V and, for example, substantially 400V. Preferably, an electric converter is arranged between the energy storage device and the electric motor, by means of which the energization of the electric motor is regulated. In an alternative, the drive additionally has an internal combustion engine, so that the motor vehicle is designed as a hybrid motor vehicle. In an alternative, a low-volt onboard power grid of the motor vehicle is supplied (speisen, sometimes referred to as power supply) by means of an energy storage device, and a DC voltage of 12V, 24V or 48V is especially provided by means of the energy storage device.

[0014] In a further alternative, the battery cell is a component of a ground transport vehicle, industrial equipment, handheld appliances such as tools, in particular battery screwdrivers. In a further alternative, the battery cell is a component of an energy supply system and is used there, for example, as a so-called buffer battery. In a further alternative, the battery cell is a component of a portable appliance, such as a portable mobile phone or other wearable device. It is also possible to use such a battery cell in the field of camping, in the field of model making or for other outdoor activities.

[0015] The battery cell has a plurality of electrodes, i.e., for example, two or preferably more. In particular, the electrodes are divided into an anode and a cathode, wherein suitably half of the electrodes form an anode and the other half form a cathode. However, preferably, there is one more anode than a cathode. Particularly preferably, all anodes and all cathodes are structurally identical relative to each other, which simplifies manufacturing. For example, the electrodes are designed to be planar and in particular have a carrier, which is also referred to as a conductor. In particular, the respective carriers are formed by means of a metal foil, which is coated at least partially on one side or on both sides. For example, aluminum is used as the metal of the carrier / conductor of the cathode, and copper is used as the metal of the conductor of the anode.

[0016] Here, the coating has a thickness of less than 1 mm. Suitably, the carrier has a thickness of less than 0.1 mm. The respective coatings preferably have active materials, binders and / or conductive additives, such as conductive carbon black. The active materials are used to absorb working ions, such as lithium ions, and are suitable for this and are arranged and configured for this. As active materials, for example, lithium metal oxides such as lithium cobalt (III) oxide (LiCoO2), NMC, such as NMC622 or NMC811, NCA, LMNO or LFP are used for the cathode, and / or LTO or graphite, silicon-based is used for the anode.

[0017] In particular, the electrodes are substantially rectangular. For example, the electrodes are stacked one on top of another to form a single cell stack, wherein the stacking direction is perpendicular to the extension direction of the electrodes arranged parallel to each other. Preferably, the anode and the cathode alternate in the stacking direction of the single cell stack. Suitably, a separator of the single cell stack is arranged between adjacent electrodes, that is, in particular between each of the anodes and one of the cathodes, which is preferably also designed to be planar. For example, all separators are structurally identical relative to each other. In particular, the electrodes are stacked substantially flush one on top of another, wherein, for example, all anodes protrude at least slightly beyond the cathode. Particularly preferably, the protrusion on one of the sides is increased. Preferably, the cathode also protrudes beyond the anode on one side, wherein the (enlarged) protrusion is located on the opposite sides of the single cell stack. In this way, the contact between the anode and the cathode and other components is simplified. Due to the stacking of the electrodes, the single cell stack is therefore also substantially rectangular.

[0018] In an alternative design, for example, all anodes, all cathodes or separators are formed by means of a common strip, or they are fastened to a common strip. The strip itself is rolled up into a cylinder or the like, thus forming a so-called "jelly roll".

[0019] The battery cell has a cell housing in which the electrodes are arranged, i.e., for example, a cell stack or a "jelly roll". Suitably, the cell housing has a base body in which the electrodes are arranged. The base body is designed, for example, in a can-shaped manner and is closed by means of a cover of the cell housing. This simplifies the arrangement of the electrodes. In particular, a volume between 0.1 dm3 and 10 dm3 is enclosed by means of the cell housing, preferably the base body. For example, the cell housing is additionally at least partially filled with an electrolyte, or the electrolyte is, for example, already partially formed by means of a respective active material. The cell housing, in particular a possible base body, is preferably designed to be rigid. In other words, the battery cell is a prismatic cell. In particular, the cell housing, preferably the base body and / or a possible cover are produced from metal, such as aluminum, i.e., pure aluminum or an aluminum alloy. The cell housing, in particular the base body, has, for example, a rectangular parallelepiped shape. Alternatively, the cell housing and preferably the base body are designed to be flexible and, for example, at least partially formed by means of a metal foil, which is coated, in particular, on one or both sides. The electrode is wrapped by means of the metal foil and the metal foil is suitably sealed at the ends in order to prevent the electrolyte from escaping and / or the ambient air from entering the cell housing.

[0020] The electrodes are especially arranged directly in the cell housing, so that the electrodes, for example, directly or via other components, are in contact with the inner wall of the cell housing and are therefore stabilized by means of it. At least the cell housing is directly used to protect the electrodes and / or prevent the electrodes / electrolytes from contacting the surrounding air or other particles. In other words, the electrodes are preferably not surrounded by other components, at least not completely surrounded by other components, in the cell housing, thereby reducing the weight and material costs of the battery cell. In particular, there is no other housing in the cell housing, by means of which the electrodes are surrounded. It is therefore feasible to fill the cell housing substantially completely with the electrodes and one / more possible separators.

[0021] Suitably, the cell housing has at least one or two through-holes, through which the connection parts are respectively guided. By means of one or more of the connection parts, at least some of the electrodes arranged in the cell housing are electrically contacted, so that it is possible to feed electrical energy from outside the cell housing to the current element formed by means of the electrodes and / or to extract electrical energy from the current element via one or more of the connection parts. If there is only a single connection part, at least some of the electrodes are electrically contacted with the cell housing, so that the potential of the cell housing is preset by means of the electrode. In particular, one or more of the connection parts are electrically insulated relative to the cell housing, wherein the connection part is connected to the cell housing in a fluid-tight manner, so that the escape of electrolyte is avoided in the area of ​​the connection part.

[0022] The cell shell, in particular a possible base body, has a wall with a theoretical fracture area. In other words, the wall has a theoretical fracture area. The wall is designed to be flat or curved / uneven, for example. Therefore, the theoretical fracture area covers a certain area of ​​the cell shell, in particular the base body, that is, a part of the wall. The theoretical fracture area is designed in such a way that it breaks under a certain pressure difference between the inside and the outside of the cell shell, so that in particular a material exchange between the inside of the cell shell and the surrounding environment can be achieved. The fracture of the theoretical fracture area is irreversible here. For example, when the pressure difference (which is also referred to as the bursting pressure in the following text) is exceeded, the theoretical fracture area is completely or only partially broken. In particular, the fracture of the theoretical fracture area and the area opened thereby depend on the pressure difference actually present.

[0023] The cell housing is designed in particular in such a way that, when the bursting pressure is exceeded, the cell housing initially only breaks in the region of the theoretical breaking region, i.e. a part of the wall, while the remaining components of the cell housing, in particular the base body, remain intact. The remaining components are damaged only when the pressure difference increases further and in this case break in particular in an uncontrolled manner. The bursting pressure is preferably selected in such a way that it is less than a pressure difference between the pressure inside the cell housing and the pressure outside the cell housing that leads to (uncontrolled) destruction of the cell housing, for example complete bursting or breaking. Preferably, the bursting pressure is between 70% and 90%, between 75% and 85% or 80% of this pressure difference.

[0024] The theoretical breaking region has an opening, which is arranged in particular in the middle region, i.e., offset inwardly from the edge of the theoretical breaking region. Suitably, the distance of the opening to the edge of the theoretical breaking region is greater than one quarter of the extension of the theoretical breaking region in the respective direction. In particular, the opening is located exactly in the middle of the theoretical breaking region. The area of ​​the opening is smaller than the area of ​​the theoretical breaking region, and in particular is smaller than 50%, 20%, 10%, 5%, 1% or 0.1% thereof.

[0025] The opening is covered by means of a gas-permeable membrane. In particular, the membrane is rigidly (i.e. immovably) connected to the cell housing, preferably the base body and / or the theoretical fracture area, so as to avoid the movement of the membrane relative to the cell housing / base body. The area of ​​the membrane is at least equal to the area of ​​the opening or preferably larger, so that the membrane completely overlaps the opening. The membrane is preferably arranged in such a way that liquid and / or gas are prevented from passing between the membrane and the theoretical fracture area. In other words, the membrane is connected to the cell housing in a gas- and fluid-tight manner, for example directly or via other components. Particularly preferably, the membrane is welded to the cell housing, for example the theoretical fracture area, appropriately using a surrounding weld. For this purpose, for example, ultrasonic, laser or temperature welding methods are used. Alternatively to this, for example, the membrane is connected to the cell housing in a form-fitting and / or material-fitting manner, in particular adhesively. Here, it is appropriate that the opening is completely surrounded by means of an adhesive or a weld. For example, the connection is made directly adjacent to the opening, or there is a distance between the opening and the connection of the membrane to the cell housing (e.g. adhesive or weld). Therefore, the escape of gas from the cell housing or into the cell housing is only possible via the opening, wherein the gas is also guided through the membrane.

[0026] In particular, the membrane is selected in such a way that it is permeable to CO, CO2, H2 and / or CH4. For example, the penetration of such gases is not hindered by the membrane, or is only hindered to a relatively small extent. However, the permeability of the membrane to moisture, in particular to water vapor, is preferably significantly lower. In particular, the membrane has a ratio of CO2 permeability to moisture permeability of at least 0.5, at least 1 or at least 1.5. This ratio is preferably greater than 0.5 and less than 3. In particular, the membrane acts as a barrier against the penetration of moisture (in particular water vapor) into the cell housing. In summary, the membrane is designed in such a way that the gas generated in the cell housing through the membrane can come out of the cell housing through the opening, for which the opening is used. With the help of the membrane, the entry of moisture and liquid (in particular water) into the cell housing is difficult or significantly reduced.

[0027] The diaphragm is produced in particular from a polymer and, for example, a thin sheet, such as a polymer sheet. Suitably, the diaphragm is produced from or composed of PTFE (i.e., polytetrafluoroethylene). Suitably, the diaphragm has a crystallinity between 85% and 100% and a density between 0.2 g / cm3 and 2 g / cm3. In the case of such material selection, gas permeability is ensured, wherein moisture, especially water vapor, is prevented from penetrating into the single cell housing by means of the diaphragm or at least this is made difficult. A diaphragm suitable for battery applications is described in WO2021 / 079163A1. For example, the diaphragm is designed to be flat. In this way, production is simplified and weight is reduced.

[0028] The recess is introduced into the wall with the theoretical fracture area, so that the recess is located in the theoretical fracture area. In particular, the recess is only located in the theoretical fracture area. The wall thickness (i.e. the thickness of the wall) is reduced by means of the recess, wherein the recess is only local. Preferably, the recess extends along a straight, wavy / curved or otherwise shaped section. The recess is preferably designed to be elongated. For example, the recess is a notch and has a V-shaped cross section in particular. Alternatively, the recess is designed according to the type of groove or groove. The recess extends until the opening, so that at least one section of the edge of the opening transitions into the recess and / or has a part of the recess.

[0029] Due to the gas-permeable membrane, continuous venting of the cell housing is substantially possible, thereby avoiding or slowing down the formation of a pressure difference between the pressure outside the cell housing and the pressure inside the cell housing, in particular due to unnecessary generation of gas in the cell housing during operation of the battery cells. On the one hand, due to the relatively small area of ​​the opening, the mechanical integrity of the cell housing is only insignificantly reduced. On the other hand, it is in principle possible for foreign substances (such as moisture or liquid) to penetrate into the cell housing only in this area, which is relatively unlikely. As a result, relatively reliable operation of the battery cell over a relatively long period of time is possible, thereby increasing the operational reliability. In other words, when the battery cell is operated without interference, due to the substantially continuous discharge via the membrane, no excessive accumulation of gas in the cell housing occurs, so that the pressure difference between the surroundings of the cell housing and the interior of the cell housing remains relatively small.

[0030] However, if, for example, due to an unwanted chemical reaction in the cell housing in the case of an overload, the pressure difference increases relatively strongly and rapidly, so that the generated gases cannot be sufficiently discharged via the openings and the membrane, the intended breaking region breaks and the cell housing opens at a defined point, that is, in the intended breaking region. Uncontrolled damage to the cell housing and uncontrolled influences on the surroundings are thus avoided. Instead, this occurs only in the region of the intended breaking region, and it is therefore possible to adapt the installation conditions of the battery cells to this. This increases the operational reliability.

[0031] The fracture / splitting begins here in the region of the recess, which represents a mechanical weakening of the wall. Since the recess extends up to the opening, the initial force expenditure is reduced for this purpose. Therefore, by means of the recess extending up to the opening, it is ensured that, on the one hand, the theoretical fracture area is actually and always split when the bursting pressure is exceeded, which increases safety. On the other hand, due to the recess extending up to the opening, the split / fracture begins at the opening and extends along the recess. The form of the split is also preset. If the bursting pressure is only slightly exceeded, the theoretical fracture area is not completely torn, but only partially torn along the recess, so that the operation of the battery cell can continue to be possible afterwards.

[0032] For example, the theoretical fracture region has a reduced wall thickness compared to the rest of the wall, wherein the wall thickness is reduced again in the region of the recess, i.e. the thickness of the wall. This ensures that when the bursting pressure is exceeded, the wall breaks only in the region of the theoretical fracture region. Alternatively, the theoretical fracture region has essentially the same wall thickness as the rest of the wall, except for possible recesses or other local reductions in the wall thickness. This simplifies production. During assembly, damage also does not occur under mechanical load, which is why the robustness is increased.

[0033] It is particularly preferred that the theoretical fracture region is formed in one piece with the rest of the wall and is preferably formed together with it. In other words, the theoretical fracture region is not formed by means of an initially separate component inserted into a corresponding recess in the wall. This simplifies production. For example, the recess is already present in the prototyping of the wall or is preferably introduced subsequently, for example by means of etching, laser or engraving. In this way, the production of the battery cell is simplified. In order to produce the battery cell, in particular, a cell housing with a (complete) wall is first produced, for which purpose, for example, an extrusion method is used. Subsequently, the opening and the recess are introduced into the wall, which opening and the recess are therefore not produced by means of prototyping of the wall. The opening is then covered with a membrane, which is preferably fastened to the cell housing.

[0034] For example, the membrane is fastened to the outside of the cell housing / wall, for example to the theoretical breaking area or to the outside of a possible matrix. In this way, the interior space of the cell housing is not filled with the aid of the membrane, so that a relatively large volume is available for the electrodes there. The capacity of the battery cell is thus increased. In this way, it is also possible to select a membrane area that is larger than the area of ​​the opening. Thus, after the gas has passed through the opening, an increased surface is available for the gas to pass through the membrane.

[0035] In an alternative, the diaphragm is arranged on the inwardly pointing side of the theoretical rupture region. In other words, the diaphragm is offset into the interior of the cell housing relative to the theoretical rupture region. In this way, the diaphragm does not bulge excessively outwards even at relatively high pressures in the cell housing when immediate gas passage is not possible due to the design of the diaphragm. Here, the diaphragm is at least partially pressed against the inwardly pointing side of the theoretical rupture region. The diaphragm is thus stabilized by means of the theoretical rupture region, which increases robustness. The passage of gas between the theoretical rupture region and the diaphragm is also prevented, which increases the tightness in this region.

[0036] Preferably, the opening is covered with a further membrane which is air-permeable, hydrophobic, i.e. at least repels water. Preferably, the material of the further membrane has a contact angle with water of greater than 80°, 90° or 100°, in particular when the material is likewise exposed to air or is in ambient air. This prevents moisture from approaching the membrane by means of the further membrane, which is why the entry of moisture into the cell housing is further impeded. However, at least moisture penetrating from the outside is prevented by means of the further membrane.

[0037] For example, the theoretical breaking region / opening is positioned arbitrarily on the cell housing. However, it is particularly preferred that, when the battery cell is designed as a soft pack cell, it is located in the region close to one of the cylindrical ends of the conductor, in which a possible membrane seals in particular (for example on a so-called airbag). In this case, the theoretical breaking region / opening is expediently offset inwards from the respective end by a maximum of up to one third of the maximum length of the cell housing.

[0038] If the battery cell is a prismatic battery cell, the theoretical fracture area / opening is preferably located in the region of the end side and / or narrow side, which is in particular not parallel to the electrodes stacked to form a possible cell stack. Alternatively, the opening is located in one of the sides of the cell housing that is parallel to the electrode, but preferably in the edge region, i.e. offset inwardly from the edge by a maximum of up to one third of the width of the side. Due to such a position of the opening, the structure is simplified and there is no need to modify the existing design of the cell stack. In addition, the theoretical fracture area / opening is therefore arranged in the region where the generated gas is concentrated, so that relatively effective removal of the gas through the opening can be achieved.

[0039] The theoretical breaking region is designed, for example, in the shape of a stadium, a circle or a rectangle. In particular, the area of ​​the theoretical breaking region is between 0.01 cm2 and 20 cm2, and preferably between 0.1 cm2 and 10 cm2. Suitably, the theoretical breaking region has a size of 0.01% and 50% of the area of ​​the cell housing. Preferably, the theoretical breaking region has a size of between 0.1% and 40% and in particular between 0.3% and 30% of the area of ​​the entire cell housing. For example, the diaphragm has an area that is 50% larger than the opening. Suitably, the opening has an area of ​​50 μm2 to 15 mm2, preferably 0.2 mm2 to 3 mm2.

[0040] Preferably, the theoretical fracture region is limited by means of further recesses. In other words, the edge of the theoretical fracture region is at least partially formed by means of further recesses, and at the edge of the theoretical fracture region, the wall thickness is thus locally reduced due to the further recesses. The wall is thus structurally weakened by means of the further recesses, so that when the bursting pressure is exceeded, splitting also occurs along the further recesses, which is why the theoretical fracture region thus also opens on the edge side.

[0041] For example, only a part of the edge of the theoretical fracture area is formed by means of other recesses. Therefore, if the wall splits along the other recesses when the bursting pressure is exceeded, the splitting does not occur along the part of the edge of the theoretical fracture area that does not have other recesses. Therefore, even when the other recesses are completely split, the components of the theoretical fracture area are still retained at the wall and bent outward, thereby forming a kind of film hinge. This prevents individual fragments of the wall from moving away uncontrolled, which prevents damage to surrounding components. Alternatively to this, the other recesses are circumferential, so that the entire theoretical fracture area is surrounded by means of the other recesses. Therefore, when the bursting pressure is exceeded and the entire other recesses split, the entire theoretical fracture area is separated from the rest of the wall, which is why a relatively fast pressure balance can be achieved. This avoids uncontrolled further destruction of the single-cell housing, which is why the operational reliability is improved.

[0042] For example, the recess is spaced apart from the other recesses. However, it is particularly preferred that the recess extends into the other recess. In other words, the two recesses transition into each other. Therefore, when the bursting pressure is exceeded, the splitting of the recess at the opening begins, and the splitting is guided to the other recess, which then also splits. In short, the splitting of the theoretical fracture area begins at the opening, extends along the recess until the other recess, and then extends along the other recess. The force consumption required for the initial splitting of the other recesses is thereby reduced. It is therefore ensured that the theoretical fracture area is at least partially split on the circumferential side, so that a relatively large part of the wall is released. A relatively fast pressure balance is thereby achieved.

[0043] For example, the angle between the recess and the other recess is arbitrary or, for example, 90°. However, it is particularly preferred that the angle between the recess and the other recess is greater than 110° compared to the transition area. The angle is preferably greater than 140° or 170°. Here, the intersection of the recess and the other recess forms the vertex of the angle. In this way, it is ensured that the splitting of the recess is also transferred to the other recess and the force consumption for starting the splitting of the other recess is reduced. For example, the recess and / or the other recess in the area of ​​the butt joint is straight. However, it is particularly preferred that the transition between them is curved. In this way, the force consumption for starting the splitting of the other recess is further reduced, which is why once the splitting has begun, it continues reliably.

[0044] For example, the theoretical fracture region has only a recess and possibly other recesses. However, it is particularly preferred that an additional recess extending in the theoretical fracture region until the opening is brought into the wall. Thus, a local reduction in wall thickness is also provided by means of the additional recess. Therefore, when the bursting pressure is exceeded, the theoretical fracture region is also opened along the additional recess, so that most of the theoretical fracture region is released relatively quickly, so that rapid pressure balance can be achieved. Preferably, the additional recess is located on the opposite side of the opening with respect to the recess. In particular, the angle between the recess and the additional recess (wherein the opening forms the vertex of the angle) is greater than 160° or 170°. Preferably, the angle is equal to 180°. Suitably, the recess and the additional recess are designed to be S-shaped and, for example, point-symmetrical relative to each other about the opening. Thus, when the bursting pressure is exceeded, a relatively large area is released quickly.

[0045] Preferably, the additional depression also extends as far as the other depression (if it is present). Therefore, the splitting of the other depression begins at two different locations, namely in the region of the intersection with the depression and in the region of the intersection with the additional depression, which is why the area released due to the splitting / fracture is further increased within a certain period of time. For example, there are only depressions extending to the opening and additional depressions. Particularly preferably, there are also further such additional depressions, i.e., they also extend to the opening, which is why the area released within a certain period of time is further increased after the bursting pressure is exceeded.

[0046] For example, the cell housing has only one single opening which is covered by the membrane. Alternatively, the cell housing comprises a plurality of such openings, each of which is covered by a membrane. In this case, for example, the membrane is designed to be continuous or each of the openings is associated with a corresponding (separate) membrane. Particularly preferably, they are introduced into the same wall.

[0047] In summary, the battery cell therefore has a second opening in addition to the opening and, if applicable, further such openings. The second opening is arranged, for example, outside the theoretical breaking region. However, it is particularly preferred that the second opening is a component of the theoretical breaking region and that the second opening is arranged symmetrically with respect to the opening. The second opening is covered here either with a diaphragm or with a further second diaphragm, so that gas can also pass through here, but moisture is prevented from entering the cell housing. For example, the edge around the second opening is complete. In other words, the area around the second opening has a constant wall thickness.

[0048] However, it is particularly preferred that a second recess extending in the theoretical fracture region up to the second opening is introduced into the wall. For example, the second opening and / or the second recess is designed to be structurally identical to the opening or the recess. Alternatively, they are different, for example, in terms of their size, so that different optimizations can be performed. Due to the second opening and the second recess, when the bursting pressure is exceeded, the theoretical fracture region also breaks open there. As a result, the area released within a certain period of time after exceeding the bursting pressure is further increased, wherein despite this, it is feasible to obtain excessive structural weakening of the cell housing or penetration of foreign particles into the battery cell in normal operation. The manufacturing cost is also not increased or only slightly increased, and the second opening and the second recess are introduced into the wall, especially in the same working step as the opening and the recess.

[0049] For example, there is an additional second recess extending to the second opening, so that the splitting also occurs in different directions starting from the second opening. If there are other recesses, the second recess especially extends to the other recesses, which is why the splitting is guided via the second recess to the other recesses.

[0050] For example, the wall area between the two openings is complete. However, it is particularly preferred that the two openings are connected by means of a connecting recess. In other words, the connecting recess is introduced into the wall, that is, likewise, a local reduction in the wall thickness is introduced into the wall, wherein the connecting recess extends between the two openings, that is, extends to the two openings. Therefore, in the case of exceeding the bursting pressure, the area between the two openings also splits by means of the connecting recess, wherein the splitting starts in particular from the two openings. This further increases the speed of releasing a certain area after exceeding the bursting pressure. For example, the connecting recess is straight or particularly preferably wavy or curved. Therefore, the length of the connecting recess increases, which is why the area for gas penetration increases after exceeding the bursting pressure, so that a relatively fast pressure balance can be achieved. It is particularly preferred that there are a plurality of such second openings and corresponding second recesses.

[0051] In particular, the size of the diaphragm is smaller than the size of the (entire) theoretical rupture area. In other words, the theoretical rupture area completely covers the diaphragm. In this way, material costs are reduced. The diaphragm surface can also be optimized in terms of necessary dimensions and its connection to the theoretical rupture area / single-cell housing independently of the size of the theoretical rupture area. In addition, after the recess is broken and the theoretical rupture area is opened, at least a portion of the surface covered by the theoretical rupture area is not covered with the diaphragm, which is why relatively unimpeded pressure balance can occur there. Alternatively, the size of the diaphragm is larger than the size of the theoretical rupture area and the diaphragm overlaps the theoretical rupture area. In this way, when the diaphragm is fastened to the single-cell housing, especially at the edge, no influencing of the theoretical rupture area occurs.

[0052] For example, the theoretical fracture area also includes other auxiliary recesses spaced apart from the opening or other openings. The auxiliary recesses, for example, extend until another of the existing recesses or are also spaced apart from the existing recesses. With the aid of the auxiliary recesses representing the structural weakening of the theoretical fracture area, the form of the split is particularly preset so that the theoretical fracture area is opened in a desired manner. For example, the recesses of the theoretical fracture area are different from each other. However, it is particularly preferred that they have substantially the same depth, which is why production is simplified. Therefore, when the bursting pressure is exceeded, its indifferent splitting also occurs, so that, for example, when a function in the recess fails (Fehlfunktion, sometimes referred to as a failure), the rest of the structure is not affected. Alternatively or in combination with this, the cross-sections of the recesses are the same as each other, so that they can be manufactured using the same tool. In another alternative, at least one of the recesses has a different depth. It is therefore feasible to preset the course of the splitting of the theoretical fracture area and adapt it, for example, to the components surrounding the battery cell in the assembled state.

[0053] The invention further relates to a combination of such a battery cell, wherein the combination is preferably a battery module or a high-voltage battery. The invention further relates to a motor vehicle, such as a passenger car (PKW), having such a battery cell, in particular such a combination. The battery cell is used in particular to energize a main drive of a motor vehicle.

[0054] The advantages and improvements described in connection with the battery cells can also be transferred to the complex / motor vehicle and vice versa, depending on the meaning. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Embodiments of the present invention are explained in more detail below according to the accompanying drawings. In which:

[0056] Figure 1 A schematically simplified illustration of a motor vehicle having a plurality of identically constructed battery cells is shown,

[0057] Figure 2 One of the battery cells is shown schematically in a sectional view with a cell housing having a desired breaking region,

[0058] Figure 3 The theoretical fracture area is schematically shown in a top view,

[0059] Figure 4 The theoretical fracture region is schematically shown in cross-section, and

[0060] Figure 5-12 A variant of the theoretical breaking region is shown schematically in each case in a top view.

[0061] In all the Figures, parts that correspond to one another are provided with the same reference numerals. DETAILED DESCRIPTION

[0062] exist Figure 1 , a motor vehicle 2 in the form of a passenger car (Pkw) is schematically and simplified. The motor vehicle 2 has a plurality of wheels 4, at least some of which are driven by means of a drive 6, which comprises an electric motor. The motor vehicle 2 is therefore an electric vehicle or a hybrid vehicle. The drive 6 has a converter, by means of which the electric motor is supplied. The converter of the drive 6 is in turn energized by means of an energy storage device 8 in the form of a high-volt battery. For this purpose, the drive 6 is connected to an interface 10 of the energy storage device 8, which is introduced into an energy storage device housing 12 of the energy storage device 8, which is made of stainless steel.

[0063] A plurality of battery modules, not shown in greater detail, of identical structure relative to one another are arranged in the energy storage housing 12 of the energy storage device 8, each of which comprises a plurality of battery cells 14. The battery cells 14 of each battery module are partially electrically connected in series with one another and partially electrically connected in parallel with one another. Some of the battery modules are then electrically connected in series with one another, and they are then electrically connected in parallel with one another. The electrical assemblies of the battery modules are in electrical contact with the interface 10, so that the battery modules and also the battery cells 14 can be discharged or charged (recharged) when the drive 6 is in operation. Due to the electrical interconnection, the voltage provided at the interface 10 (which is 400 V) is a multiple of the voltage provided by each of the battery modules and also by each of the battery cells 14.

[0064] exist Figure 2 In the figure, one of the battery cells 14 with the same structure relative to each other is presented in a cross-sectional view. The battery cell 14 has a plurality of anodes 16 and cathodes 18, of which only two are shown respectively. The anodes 16 and cathodes 18 forming the electrodes 20 of the battery cell 14 are each designed to be planar and alternately stacked to form a cell stack, wherein a separator not shown in more detail is arranged between the respectively adjacent anodes 16 and cathodes 18. The anode 16 protrudes beyond the cathode 18 on a common side, that is, there is a respective discharger, which is formed by a respective metal foil. In the region of the protrusion, the respective conductor has no other components here, but in other regions, a coating, which is also called a carrier, is applied to the respective conductor, which carrier includes an active material. The cathode 18 also protrudes beyond the anode 16 in the same way, wherein the protrusion is located on the opposite side of the stack formed by means of the anode 16 and the cathode 18.

[0065] The protruding parts of the anode 16 and the cathode 18 are respectively welded to the associated busbars 22 produced from copper. Here, one of the busbars 22 is respectively associated with the anode 16 and the cathode 18. The busbars 22 each have a connection 24, which is guided through a rectangular cell housing 26, in which the anode 16 and the cathode 18 are arranged. The cell housing 26 is designed to be rigid and is produced from aluminum. Therefore, the battery cell 14 is a prismatic cell. The cell housing 26 is filled with a liquid electrolyte that is not shown in detail.

[0066] The cell housing 26 has a wall 28 with a theoretical breaking region 30 having an area of ​​5 cm2. The theoretical breaking region 30 is designed such that it breaks when the pressure difference between the pressure outside the cell housing 26 and the pressure inside the cell housing 26 exceeds a bursting pressure of 1 bar, so that the cell housing 26 opens and pressure compensation can occur. The bursting pressure is 90% of the maximum pressure load on the cell housing 26, i.e., at which irreversible and uncontrolled destruction of the cell housing 26 occurs.

[0067] exist Figure 3 In the schematic diagram, a top view is shown. Figure 4 2 shows schematically a cross-sectional view of the theoretical breaking region 30. The theoretical breaking region 30, which is integral with the rest of the wall 28, is stadium-shaped and has an opening 32 and a second opening 34, which are respectively led through the entire theoretical breaking region 30, i.e. the wall 28. On the inside, the opening 32 and the second opening 34 are covered by means of a gas-permeable membrane 36, which is fastened, for example, by means of welding, to the inside of the wall 28, i.e. the inside of the theoretical breaking region 30. Here, the size of the membrane 36 is smaller than the size of the theoretical breaking region 30, but it is possible for particles to pass from the inside of the cell housing 26 to the outside and vice versa only through the membrane 36. The membrane 36 is made of PTFE, so that moisture is prevented from entering the interior of the cell housing 26 by means of the membrane. However, it is possible for CH4, for example, to escape from the cell housing 26 through the membrane 26 and the opening 32 and the second opening 34.

[0068] The depression 38 extending to the opening 32 is introduced into the desired breaking region 30, that is, into the inner side of the wall 28. The depression 38 has a corrugated / curved course and extends to the opening 32, wherein the depression 38 is partially covered by means of the membrane 36, and wherein the membrane 36 partially fills the depression 38. The depression 38 is a local reduction in the thickness of the wall thickness of the wall 28 in the desired breaking region 30, wherein the cross section of the depression 38 is rectangular in the example presented.

[0069] In addition, two additional recesses 40 extending in the theoretical breaking region 30 up to the opening 32 are introduced into the wall 28, wherein the two recesses also have a wave-shaped or curved course. The depth of the additional recess 40 corresponds to the depth of the recess 38, and they are also designed in the same way in other respects. Here, one of the additional recesses 40 is arranged point-symmetrically with respect to the recess 38 with respect to the opening 32. Therefore, the recess 38 and the additional recess 40 are butted at an angle of 180° at the opening 32. The remaining additional recesses 40 are rotationally symmetrical about the opening about the recess 38 or another additional recess 40 about an angle of 90°.

[0070] Likewise, a second recess 42 extending in the desired breaking region 30 up to the second opening 34 is introduced into the wall 28, which second recess 42 is substantially identical in structure to the recess 38, but is offset relative to the second opening 34. In other words, the course of the second recess 42 is identical to the course of the recess 38. The second opening 34 is also associated with two additional second recesses 44, which are introduced into the wall 28 in the desired breaking region 30 and which extend up to the second opening 34. One of the additional second recesses 44 is point-symmetrical with respect to the second recess 42 with respect to the second opening 34, and the remaining additional second recesses 44 are rotationally symmetrical about an angle of 90° with respect to the second recess 42 and the other additional second recess 44 with respect to the second opening 42. The recess 38, the additional recess 40, the second recess 42 and the additional second recess 44 always have the same cross section and the same length and the same course, wherein only the orientation and / or association with respect to the respective openings 32, 34 are different.

[0071] The desired breaking region 30 is limited by means of a circumferential further recess 46, which thus forms the edge of the desired breaking region 30. The course of the further recess 46 is therefore stadium-shaped, wherein the cross section of the further recess 46 corresponds to the cross section of the recess 38. The recess 38, the additional recess 40, the second recess 42 and the additional second recess 44 extend up to the further recess 46 and transition into it. Here, due to the curved course of the recess 38, the additional recess 40, the second recess 34 and the additional second recess 44, the angle formed between them and the further recess 46 in each case at the intersection is greater than 110°, wherein there is a substantially continuous transition.

[0072] Furthermore, a connecting recess 48 is introduced into the inner side of the wall 28, which extends as far as the opening 32 and the second opening 34. In other words, the two openings 32, 34 are connected by means of the connecting recess 48. The depth and the cross section of the connecting recess 48 correspond to the respective values ​​of the recess 38. The course of the connecting recess 48 is wavy, and one of the additional recesses 40 adjoins it at the opening 32 at an angle of 180°, and one of the additional second recesses 44 adjoins it at the second opening 34 likewise at an angle of 180°.

[0073] When the battery cell 14 is in operation, it is possible that gas is generated in the cell housing 26 due to an undesired chemical reaction. The gas can escape from the cell housing 26 to the outside via the diaphragm 36 and the two openings 32, 34, so that no excessive pressure increase occurs. In the case of a malfunction or excessive load, it is possible that the speed of gas discharge is not sufficient to limit the pressure increase in the cell housing 26. If the pressure difference between the inside and the outside of the cell housing 26 exceeds a limit value, that is, the bursting pressure, the theoretical breaking area 30 begins to tear from the opening 28 along the recess 38 and the additional recess 40 and along the connecting recess 48. The theoretical breaking area 30 also begins to split from the second opening 34 along the second recess 42, the additional second recess 44 and the connecting recess 48. Due to the local reduction in wall thickness, the force required to start the split is reduced, so that it always starts when the splitting bursting pressure is exceeded. Due to the splitting, the area for gas escape increases, so that the pressure increase is limited. Once the pressure is no longer increasing, cleaving ceases and the theoretical fracture zone 30 remains partially open.

[0074] However, if there is a more serious functional failure and the pressure difference continues to increase, the splitting continues. The splitting occurs for such a long time here, that is, until the entire recess 38, the additional recess 40, the connecting recess 48, the second recess 42 and the additional second recess 44 are completely split. The splitting transitions from them to the other recesses 46, which therefore also begin to split, that is, at six different positions. Since each recess 38, 40, 42, 44 transitions to the other recess 46, the other recess 46 splits from these positions in the clockwise direction in the example presented. When the other recesses 46 are completely split, the various components of the theoretical fracture area 30 are separated from the rest of the wall 28 and fall off from it due to the overpressure in the single cell housing 26. There is thus a relatively large surface for pressure balance, so that at least the pressure rise stops. In this way, it is prevented that the single cell housing 26 breaks in an uncontrolled manner. Even if the battery cell 14 is no longer readily available, further components of the motor vehicle 2 which are located in the surroundings of the battery cell 14 are therefore not damaged.

[0075] exist Figure 5-11 In, according to Figure 3 The illustrations of FIG. 4 show different designs of the theoretical breaking region 30 , which are however always stadium-shaped. The respective theoretical breaking region 30 is also respectively limited by means of further recesses 46 . Figure 5 In the variant presented in , the diaphragm 36 and the two openings 32, 34 are not changed. There is no connecting recess 48, no additional recess 40, no additional second recess 44. There are recesses 38 and second recesses 42 extending to the respective openings 32, 34. However, they are now designed to be straight and point away from the respective other openings 32, 34 in the direction of the other recesses 46. The recess 38 and the second recess 42 are spaced apart from the other recesses 46 here. In this design form, the area initially released by the splitting of the two recesses 38, 42 is limited, so that the operation of the battery cell 14 continues to be feasible when the pressure increase is relatively small. Only when the pressure difference is relatively large, the other recesses 46 are split, thereby releasing the entire theoretical fracture area 30.

[0076] Figure 6 A modification of the theoretical fracture region 30 presented in Figure 5 In contrast, only the recessed portion 38 and the second recessed portion 42 are extended and bent at the end, so that they pass into the other recessed portion 46 via the respective bends. Therefore, after the recessed portion 38 or the second recessed portion 42 is completely split, it is introduced into the other recessed portion 46 via the respective intersection points with the other recessed portion 46. In this way, the continuous splitting and release of the theoretical breaking region 30 is basically achieved.

[0077] Figure 7 , in which the two openings 32, 34, the membrane 36 and the further recess 46 are also present unchanged. The recess 38 then extends from the opening 32 to the further recess 46, and one of the additional recesses 40 is present, which is arranged point-symmetrically with respect to the recess 38 with respect to the opening 32. The course of the recess 38 and the additional recess 40 is now straight and perpendicular to the course of the longitudinal axis of the stadium-shaped theoretical fracture region 30. In other words, the recess 38 and the additional recess 40 each open into the further recess 46 at an angle of 90°. The second recess 42 is designed to correspond to the recess 38, and one of the additional second recesses 44 is present, which is shaped correspondingly to the additional recess 40. In this modification, after the other recessed portions 38, 40, 42, 44 are completely cleaved, the other recessed portions 46 begin to cleave in two directions from the intersections with these other recessed portions 38, 40, 42, 44, so that the speed at which the other recessed portions 46 are completely cleaved increases.

[0078] Figure 8 The variation of the theoretical breaking region 30 presented in the diagram corresponds essentially to Figure 7 . Only the other recess 46 is modified and is no longer circumferential. In other words, the other recess 46 is now divided into two partial sections, and the theoretical fracture area 30 transitions essentially continuously into the rest of the wall 28 at two different locations. The two locations are located at opposite ends along the longitudinal axis of the theoretical fracture area 30, wherein the theoretical fracture area 30 is designed to be axisymmetric about the longitudinal axis. Due to the discontinuous design of the other recess 46, some components of the theoretical fracture area 38 remain at the rest of the wall 28 after complete rupture. These components of the theoretical fracture area 30 are bent outwardly relative to the cell housing 26 due to the pressure difference. In this way, the formation of fragments is avoided, which would lead to unnecessary interactions with components around the battery cell 14.

[0079] Fig. 9 , another design of the theoretical fracture region 30 is shown in FIG. 3 , in which the two openings 32, 34 and the membrane 36 are unchanged. The two openings 32, 34 are connected by means of a connecting recess 48, which is straight and extends along the longitudinal axis of the stadium-shaped theoretical fracture region 30. On the side opposite to the connecting recess 48 with respect to the opening 32, the recess 38 bent into an S shape leads to the opening 32. The opposite end of the recess 38 leads to the other recess 46. The second recess 42 is designed to be mirrored and also S-shaped, so that it leads to the second opening 34 at the end of the second opening 34 opposite to the connecting recess 48. The other recess 46 is designed to be shortened and starts at the recess 38 and the second recess 42 therein. Therefore, when all recesses 38, 42, 46, 48 are broken, a part of the share of the theoretical fracture region 30 is also retained at the rest of the wall 28.

[0080] Fig.10 , another embodiment of the theoretical fracture region 30 is presented, in which the other recessed portion 46 is again designed to be circumferential. The diaphragm 36 also exists unchanged. The second opening 34 is omitted, so that only the opening 32 exists, which is now arranged in the center of the theoretical fracture region 30. The straight recessed portion 38 and one of the straight additional recessed portions 40 lead to the opening 32 on the opposite side, that is, at an angle of 180° to each other. The recessed portion and the additional recessed portion 40 each lead to the other recessed portion 46 at an angle of 120°. In this variant, the production of the theoretical fracture region 30 is simplified.

[0081] Fig.11, the final design form of the theoretical fracture region 30 is presented, wherein the other recesses 46 and the opening 32 are unchanged compared to the previously shown example. There are also recesses 38 and additional recesses 40, which extend straight and are located on the opposite side with respect to the opening 32. However, they are now arranged perpendicular to the direction of the theoretical fracture region 30 and therefore intersect with the other recesses 46 at an angle of 90°. The diaphragm 36 is designed to extend in the longitudinal direction and cover the second opening 34, which is now arranged outside the theoretical fracture region 30. With respect to the opening 32 and the second opening 34, mirror-symmetrically, other openings 50 are introduced into the wall 28, and the other openings 50 are also covered by means of the extended diaphragm 36. In the variant presented, gas escape via all three openings 32, 34, 50 is feasible. In the case of the theoretical fracture region 30 being split, the second opening 34 and the other openings 50 are not affected. In the example presented, the membrane 36 is designed to be narrower than the theoretical breaking area 30. In a variant not presented in greater detail, the membrane 36 is enlarged so that the entire theoretical breaking area 30 is covered by means of the membrane 36. This design of the membrane 36 can also be used in other examples of the previous examples.

[0082] Fig.12 The variant presented in corresponds essentially to Figure 3 Only the membrane 36 is enlarged so that it is now larger than the theoretical breaking area 30. The membrane 36 also completely overlaps the theoretical breaking area 30.

[0083] The present invention is not limited to the embodiments described above. On the contrary, those skilled in the art can also derive other modifications of the present invention therefrom without departing from the subject matter of the present invention. In particular, all individual features described in connection with the various embodiments can also be combined with each other in another manner without departing from the subject matter of the present invention.

[0084] Reference Symbols List

[0085] 2 Motor vehicles

[0086] 4 wheels

[0087] 6. Drive

[0088] 8Energy storage

[0089] 10 interfaces

[0090] 12Energy storage housing

[0091] 14 battery cells

[0092] 16 Anode

[0093] 18 cathode

[0094] 20 electrodes

[0095] 22 Busbar

[0096] 24 connection part

[0097] 26 single cell housing

[0098] 28 walls

[0099] 30 Theoretical fracture area

[0100] 32 openings

[0101] 34 Second opening

[0102] 36 Diaphragms

[0103] 38 concave part

[0104] 40 Additional recessed portion

[0105] 42 second recess

[0106] 44 Additional second recess

[0107] 46 Other recessed parts

[0108] 48 connection recess

[0109] 50 Other openings

Claims

1. A battery cell (14) having a cell housing (26) in which a plurality of electrodes (20) are arranged, and wherein the cell housing (26) has a wall (28) with a desired breaking region (30), wherein the desired breaking region (30) comprises an opening (32) which is covered by means of a gas-permeable membrane (36), and wherein a recess (38) extending up to the opening (32) is introduced into the wall (28) in the desired breaking region (30).

2. The battery cell (14) according to claim 1, characterized in that: The desired breaking region (30) is limited by means of further depressions (46).

3. The battery cell (14) according to claim 2, characterized in that: The further recess (46) is circumferential.

4. The battery cell (14) according to claim 2 or 3, characterized in that: The depression (38) extends as far as the further depression (46).

5. The battery cell (14) according to claim 4, characterized in that: The angle formed between the recessed portion (38) and the further recessed portion (46) is greater than 110°.

6. The battery cell (14) according to any one of claims 1 to 5, characterized in that: An additional depression (40) extending as far as the opening (32) is introduced into the wall (28) in the desired breaking region (30).

7. The battery cell (14) according to any one of claims 1 to 6, characterized in that: The intended breaking region (30) comprises a second opening (34), wherein a second depression (42) extending as far as the second opening (34) is introduced into the wall (28) in the intended breaking region (30).

8. The battery cell (14) according to claim 7, characterized in that: The two openings (32, 34) are connected by means of a connecting recess (48).

9. The battery cell (14) according to any one of claims 1 to 8, characterized in that The size of the membrane (36) is smaller than the size of the theoretical rupture region (30).

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