Battery cell

Abstract

The invention relates to a battery cell (14) having a cell housing (28) in which a plurality of electrodes (20) are arranged. The battery housing (28) has a predetermined rupture region (30), wherein the predetermined rupture region (30) has an opening (36). The opening (36) is covered by a gas permeable membrane (38).

Description

Technical Field

[0001] The invention relates to a battery cell having a battery housing in which a plurality of electrodes are arranged. Background Art

[0002] More and more motor vehicles are at least partially driven by electric motors, so that they are designed as electric vehicles or hybrid vehicles. For the powering of the electric motors, a high-voltage battery is usually used, which includes a plurality of individual battery modules. These battery modules are usually structurally identical to one another and are electrically connected in series and / or in parallel to one another, so that the voltage applied to the high-voltage battery corresponds to a multiple of the voltage provided by 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 are electrically connected in series and / or in parallel to one another.

[0003] The battery cells, each of which generally comprises a plurality of primary cells. They each have two electrodes, namely an anode and a cathode, and a separator arranged between them and an electrolyte having freely movable charge carriers. As such an electrolyte, a liquid is used, for example. In an alternative, the battery cell is designed as a solid-state battery and the electrolyte exists as a solid. The anode and cathode forming the battery cell electrodes generally include a carrier acting as a current collector. The active material is generally fixed thereon, and it is a component of a layer applied to the carrier, which is also referred to as a current collector. In this case, the electrolyte may already be present in the layer, or the electrolyte may be introduced afterwards. However, the active material is at least suitable for absorbing working ions, such as lithium ions. Different materials for the carrier and different types of layer materials are used depending on the use as an anode or cathode.

[0004] In order to protect the galvanic cells, they are usually arranged in the battery housing of the battery cell, which is also called a battery cup. The electrolyte can also be protected from environmental influences by the battery housing. In order to provide a relatively large capacity by the corresponding battery cell, a plurality of such galvanic cells, usually up to 100, are usually arranged in a common battery housing. In order to utilize the existing space more efficiently and simplify production, the various components of the galvanic cell are designed to be flat and stacked one above the other in the stacking direction, thereby forming a substantially rectangular battery stack. In an alternative embodiment, for example, the separator is designed in the form of a strip and a plurality of electrodes are respectively provided on the opposite sides. The strip is rolled into a roll, in particular a so-called "jelly roll". Therefore, the galvanic cell is rolled into a cylindrical shape.

[0005] The way in which the battery housing is shaped depends on the galvanic cell arrangement used. In this case, it can be designed strictly and made, for example, from aluminum. In this case, the battery housing is, for example, in the shape of a cuboid. Such battery cells are also referred to as prismatic cells. In an alternative embodiment, the battery housing is produced by winding a foil of a galvanic cell. Such battery cells are also referred to as so-called pouch cells.

[0006] When a battery cell is in operation, i.e. is charged and discharged, gases may be generated due to undesired chemical reactions. As a result, the pressure inside the battery housing increases, so that on the one hand, the individual electrodes may lose contact, which leads to a loss of performance of the battery cell. On the other hand, the battery housing may be deformed due to the increased pressure, so that in particular the environment of the battery cell is mechanically influenced. At relatively high pressures, the battery housing ruptures, so that the electrolyte escapes and the entire battery cell is no longer usable. It is also possible that individual components of the battery cell react chemically with the surroundings in an undesired manner.

[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 when such materials are used. As an alternative to this, for example, additional elements are present in the battery housing, for example by which the gases produced are combined and / or converted. In another variant, the battery housing is designed to be relatively robust, so that during operation of the battery cell, a pressure is never reached that leads to a rupture of the battery housing. However, due to the robust design of the additional elements or the battery housing, the weight of the battery cell and the structural space are increased, which is why the energy density is reduced. The object on which the present invention is based is to specify a particularly suitable battery cell in which the operating reliability and / or the energy density are advantageously increased. Summary of the invention

[0008] This object is achieved according to the invention by the features of claim 1. Advantageous refinements and embodiments are the subject matter of the dependent claims.

[0009] The battery cells are particularly designed to be rechargeable and are preferably secondary batteries. Preferably, the battery cells are a component of a motor vehicle in a prescribed state. The battery cells are suitable for this purpose and are particularly arranged and established for this purpose. In a prescribed state, the battery cells are, for example, a component of an energy storage device of a motor vehicle, which has a plurality of such battery cells. In this case, the battery cells are preferably divided into a plurality of battery modules, which are structurally identical to each other. These battery cells are particularly arranged in the housing of the energy storage device or the corresponding battery module and are electrically connected to each other in parallel and / or in series. Therefore, the voltage applied to the energy storage device / battery module is a multiple of the voltage provided by each of the battery cells. Preferably, all battery cells are structurally identical here, which simplifies production.

[0010] The housing of the energy storage device or the corresponding battery module is preferably made of metal, for example, steel, such as stainless steel, or an aluminum alloy, which therefore in particular forms a composite of such battery cells. For example, it is produced using a die casting method, a deep drawing method, a casting press or an extrusion method. In particular, the housing of the energy storage device or the corresponding battery module is designed to be closed. Suitably, an interface is introduced into the housing of the energy storage device or the corresponding battery module, which forms the connection end of the energy storage device / battery module. The interface is in electrical contact with the battery cell here, so that if a corresponding plug is plugged in at the connection end, electrical energy can be fed in and / or electrical energy can be extracted from the battery cell outside the energy storage device.

[0011] The motor vehicle is preferably for land use and preferably has a number of wheels, at least one, preferably a plurality or all of which are driven by means of a drive. In particular, one of the wheels, preferably a plurality of wheels, is designed to be controllable. It is thus possible for the motor vehicle to move independently of a specific roadway, such as a track or the like. It is expediently possible here to position the motor vehicle substantially arbitrarily on a roadway, which is made in particular of 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 passenger car (PKW).

[0012] The forward movement of the motor vehicle is preferably carried out by means of a drive device. For example, the drive device, in particular the main drive device, is at least partially designed to be electrical, 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-voltage battery pack. A DC voltage is appropriately provided by means of the high-voltage battery pack, 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 device additionally has an internal combustion engine, so that the motor vehicle is designed as a hybrid motor vehicle. In an alternative, the low-voltage onboard power supply of the motor vehicle is fed by means of the energy storage device, and a DC voltage of 12V, 24V or 48V is especially provided by means of the energy storage device.

[0013] In one alternative, the battery cell is a component of a land vehicle, an industrial device or a handheld device, such as a tool, in particular a battery screwdriver. In a further alternative, the battery cell is a component of an energy supply device 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 device, 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, model building or for other outdoor activities.

[0014] The battery cell has a plurality of electrodes, for example two or preferably more electrodes. In particular, the electrodes are divided into anodes and cathodes, wherein expediently half of the electrodes conveniently form the anode and the other half forms the cathode. Preferably, however, there is one more anode than cathode. Particularly preferably, all anodes and all cathodes are identical in construction to one another, which simplifies production. For example, the electrodes are designed to be flat and, in particular, have a carrier, which is also referred to as a current collector. In particular, the individual carriers are formed by a metal foil, which is coated at least in sections on one or both sides with a layer. For example, aluminum is used as the metal of the carrier / current collector of the cathode, and copper is used as the metal of the current collector of the anode.

[0015] In this case, the thickness of the layer is less than 1 mm. The carrier preferably has a thickness of less than 0.1 mm. The corresponding layer preferably has an active material, a binder and / or a conductive additive, such as conductive carbon black. The active material is used to absorb working ions, such as lithium ions, and is suitable for this and is arranged and set up for this purpose. For example, lithium metal oxides, such as lithium cobalt (III) oxide (LiCoO2), NMC, such as NMC622 or NMC811, NCA, LMNO or LFP are used as active materials for the cathode, and / or LTO or graphite, Si-based materials are used as active materials for the anode.

[0016] In particular, the electrodes are substantially rectangular. For example, the electrodes are stacked one above the other to form a battery stack, wherein the stacking direction is perpendicular to the extension direction of the electrodes arranged parallel to each other. In this case, the anode and cathode are preferably alternated in the stacking direction of the battery stack. The separators of the battery stack are preferably arranged between adjacent electrodes, that is, in particular between one of the anodes and one of the cathodes, respectively, and the separators are preferably also designed to be flat. For example, all separators are structurally identical to each other. In particular, the electrodes are stacked up and down substantially flush with each other, wherein all anodes, for example, protrude at least slightly beyond the cathodes. Particularly preferably, in this case, the protrusion on one side is particularly preferably enlarged. Preferably, the cathode also protrudes beyond the anode on one side, wherein the (enlarged) protrusion is located on the opposite sides of the battery stack. In this way, the contact of the anode and cathode with other components is simplified. Due to the stacking of the electrodes, the battery stack is therefore also substantially square.

[0017] In alternative designs, for example, all anodes, all cathodes or separators are formed by 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".

[0018] The battery cell has a battery housing, in which electrodes are arranged, i.e., for example, a battery stack or "jelly roll". The battery housing has a matrix in a suitable manner, in which electrodes are arranged. In this case, the matrix is, for example, designed in a can shape and closed by a cover of the battery housing. The arrangement of the electrodes is thus simplified. In particular, a volume between 0.1 dm3 and 10 dm3 is surrounded by the battery housing, preferably the matrix. For example, the battery housing is additionally at least partially filled with an electrolyte, or the electrolyte is, for example, already partially formed by a corresponding active material. The battery housing, in particular a possible matrix, is preferably designed to be rigid. In other words, the battery cell is a prismatic battery. In particular, the battery housing, preferably the matrix and / or a possible cover are made of metal, such as aluminum, i.e., pure aluminum or an aluminum alloy. The battery housing, in particular the matrix, has, for example, a cuboid shape. Alternatively, the battery housing, preferably the matrix, is designed to be flexible and, for example, at least partially formed by a metal foil, which is particularly coated on one or both sides. The electrodes are wound around the metal foil, and the metal foil is suitably sealed at the ends to prevent leakage of electrolyte and / or ambient air from entering the battery housing.

[0019] The electrodes are in particular arranged directly in the battery housing, so that the electrodes rest on the inner wall of the battery housing, for example directly or via another component, and are thereby stabilized. At least the battery housing serves directly to protect the electrodes and / or to prevent the electrodes / electrolyte from coming into contact with the ambient air or other particles. In other words, the electrodes in the battery housing are preferably not, at least not completely, surrounded by another component, thereby reducing the weight and material costs of the battery cell. In particular, there is no additional housing in the battery housing for surrounding the electrodes. Thus, the battery housing can be substantially completely filled with the electrodes and possibly the separator / s.

[0020] Suitably, the battery housing has at least one or two slits through which the connection terminals are respectively guided. Via the one or more connection terminals, at least some of the electrodes arranged in the battery housing are electrically contacted, so that electrical energy can be fed to the galvanic cell formed by the electrodes from outside the battery housing and / or electrical energy can be extracted from the galvanic cell formed by the electrodes via the one or more connection terminals. If only a single connection terminal is present, at least some of the electrodes are electrically contacted with the battery housing, so that the potential of the battery housing is predetermined by these electrodes. In particular, the one or more connection terminals are electrically insulated from the battery housing, wherein these connection terminals are connected to the battery housing in a fluid-tight manner, thereby avoiding leakage of electrolyte in the area of ​​the connection terminals.

[0021] The battery housing, in particular the possible matrix, has a predetermined rupture area. Therefore, the predetermined rupture area covers a specific area of ​​the battery housing, in particular the matrix. The predetermined rupture area is designed so that it ruptures under a specific pressure difference between the inside and the outside of the battery housing, so that in particular a material exchange between the inside of the battery housing and the surrounding environment is possible. The rupture of the predetermined rupture area is irreversible in this case. For example, if the pressure difference (which is also referred to as the bursting pressure in the following text) is exceeded, the entire predetermined rupture area ruptures, or only partially ruptures. In particular, the area of ​​the predetermined rupture area that ruptures and is thus opened depends on the actual pressure difference.

[0022] The battery housing is designed in this case in particular such that when the bursting pressure is exceeded, the battery housing initially only bursts in the region of the predetermined bursting region, while the remaining components of the battery housing, in particular the base body, remain intact. Only when the pressure difference increases further do they burst in this case, in particular in an uncontrolled manner. The bursting pressure is preferably selected so that it is less than the pressure difference between the pressure inside the battery housing and the pressure outside the battery housing, which would lead to damage to the battery housing, such as a complete burst or rupture. Preferably, the bursting pressure is between 70% and 90%, 75% and 85% or 80% of this pressure difference.

[0023] The predetermined rupture zone has an opening which is arranged in particular in the central region, i.e. offset inwardly from the edge of the predetermined rupture zone. Suitably, the distance from the opening to the edge of the predetermined rupture zone is greater than one quarter of the extent of the predetermined rupture zone in the corresponding direction. In particular, the opening is located exactly in the middle of the predetermined rupture zone. The area of ​​the opening is smaller than the area of ​​the predetermined rupture zone, and in particular is smaller than 50%, 20%, 10%, 5%, 1% or 0.1% thereof.

[0024] The opening is covered by a gas-permeable membrane. In particular, the membrane is rigidly, i.e., immovably connected to the battery housing, preferably to the substrate and / or the predetermined rupture area, so as to avoid movement of the membrane relative to the battery housing / substrate. 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. In particular, the area of ​​the membrane is smaller than the area of ​​the entire predetermined rupture area. In this way, material costs are reduced. In view of the necessary active area and its connection to the predetermined rupture area / battery housing, the membrane surface can also be optimized independently of the area of ​​the predetermined rupture area. Alternatively, the area is larger than the area of ​​the predetermined rupture area and the membrane overlaps the predetermined rupture area. In this way, when the membrane is fixed to the battery housing, especially at the edge, there is no effect on the predetermined rupture area.

[0025] The diaphragm is preferably arranged in such a way that liquid and / or gas are prevented from passing between the diaphragm and the predetermined rupture area. In other words, the diaphragm is connected to the battery housing in an airtight and fluid-tight manner, for example directly or via other components. For this purpose, the diaphragm is particularly preferably welded to the battery housing, such as the predetermined rupture area, by a surrounding weld. For example, ultrasonic, laser or temperature welding methods are used for this purpose. Alternatively to this, for example, the diaphragm is connected to the battery housing, in particular bonded to the battery housing, in a form-fitting and / or material-joined manner. In this case, the opening is suitably completely surrounded by an adhesive or a weld. For example, the connection is carried out directly adjacent to the opening, or a gap is formed between the opening and the connection between the diaphragm and the battery housing (such as an adhesive or a weld). Therefore, the gas can only escape from the battery housing or enter the battery housing through the opening, wherein the gas is also guided through the diaphragm.

[0026] In particular, the membrane is selected so that it can be permeable to CO, CO2, H2 and / or CH4. For example, the membrane does not hinder the passage of such gases, or only hinders their passage to a relatively small extent. However, the membrane is preferably significantly less permeable to moisture, especially water vapor. In particular, the ratio of the CO2 permeability of the membrane to the moisture permeability is 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, especially water vapor, into the battery housing. In short, the membrane is designed so that the gas generated in the battery housing can leave the battery housing through the opening, and the opening is used for this purpose. With the help of the membrane, the entry of liquid, especially water into the battery housing becomes more difficult or significantly reduced. Due to the breathable membrane, continuous degassing of the battery housing is basically possible, so as to avoid or slow down: in particular, due to the undesirable generation of gas in the battery housing during the operation of the battery cell, a pressure difference is formed between the pressure outside the battery housing and the pressure inside the battery housing. On the one hand, the mechanical integrity of the battery housing is only slightly reduced due to the relatively small opening area. On the other hand, foreign substances such as moisture or liquids can in principle only penetrate into the battery housing in this area, which is relatively unlikely. As a result, the battery cells can be operated relatively safely for a relatively long period of time, thereby increasing the operating reliability. In other words, when the battery cells are operated without interference, no excessive gas can accumulate in the battery housing due to the essentially continuous discharge through the membrane, so that the pressure difference between the battery housing surroundings and the interior of the battery housing remains relatively low.

[0027] However, if, due to undesired chemical reactions in the cell housing, for example in the case of an overload, the pressure difference increases relatively strongly and rapidly, so that the gases produced cannot be sufficiently discharged through the opening and the membrane, the predetermined rupture region ruptures and the cell housing is opened at a defined position, i.e. in the predetermined rupture region. Uncontrolled damage to the cell housing and uncontrolled influences on the surroundings are thus avoided. Instead, this occurs only in the area of ​​the predetermined rupture region, so that the installation situation of the battery cells can be adapted thereto. The operational reliability is thus increased.

[0028] The diaphragm is particularly made of a polymer and is, for example, a film, such as a polymer film. The diaphragm is suitably made of PTFE (i.e., polytetrafluoroethylene) or composed of PTFE (i.e., polytetrafluoroethylene). The diaphragm preferably has a crystallinity between 85% and 100% and a density between 0.2g / cm3 and 2g / cm3. In the case of such material selection, gas permeability is obtained, wherein moisture, in particular water vapor, is prevented from penetrating into the battery housing by means of the diaphragm or at least makes it more difficult. A diaphragm suitable for battery applications is described in WO 2021 / 079163 A1. For example, the diaphragm is designed to be flat. In this way, production is simplified and weight is reduced. For example, the predetermined rupture area / opening is positioned at any place on the battery housing. However, if the battery cell is designed as a pouch cell, it is particularly preferably located in the region of one of the ends of the cylindrical shape close to the current collector, in which a possible diaphragm (e.g., on a so-called airbag) is particularly sealed. In this case, the predetermined rupture region / opening is expediently located at one third of the maximum length of the battery housing from the respective end up to the maximum inward deflection.

[0029] If the battery cell is a prismatic cell, the predetermined rupture area / opening is preferably located in the region of the end faces and / or narrow sides, which are in particular not parallel to the electrodes of the layered battery stack. Alternatively, the opening is located in one of the sides of the battery housing that is parallel to the electrode, but preferably in the edge region, i.e. offset inwardly from the edge by up to one third of the side width. Due to such a position of the opening, the construction is simplified and there is no need to modify the existing design of the battery stack. In addition, the predetermined rupture area / opening is therefore arranged in the region where the generated gas accumulates, so that the gas can be transported away relatively effectively through the opening. For example, the predetermined rupture area has only a single opening covered with a diaphragm. Alternatively to this, the predetermined rupture area includes a plurality of such openings, each of which is covered by a diaphragm. In this case, for example, the diaphragm is designed to be continuous, or each opening is assigned a corresponding (separate) diaphragm.

[0030] The predetermined rupture region is designed, for example, in the shape of a stadium, a circle or a rectangle. In particular, the area of ​​the predetermined rupture region is between 0.01 cm2 and 20 cm2, and preferably between 0.1 cm2 and 10 cm2. Suitably, the size of the predetermined rupture region is between 0.01% and 50% of the area of ​​the battery housing. The predetermined rupture region preferably has a size between 0.1% and 40%, in particular between 0.3% and 30%, of the area of ​​the entire battery housing. For example, the area of ​​the membrane is 50% larger than the opening. Suitably, the opening has an area of ​​50 μm 2 to 15 mm 2, preferably 0.2 mm 2 to 3 mm 2.

[0031] The opening is preferably covered with a further membrane which is air-permeable, hydrophobic, i.e. at least waterproof. Preferably, the material of the further membrane has a contact angle with water of greater than 80°, 90° or 100°, in particular if the material is also exposed to air or is in ambient air. Moisture is blocked from the membrane by the further membrane, which makes it more difficult for moisture to enter the battery housing. However, moisture penetration from the outside is at least blocked by the further membrane.

[0032] In particular, the two diaphragms are arranged in parallel, and the other diaphragms are suitably completely covered by the diaphragm. Preferably, the other diaphragms are fixed to the battery housing in a fluid-tight manner, for example, fixed to the predetermined rupture area. For example, the opening is directly covered by the other diaphragms, and the other diaphragms are directly fixed to the battery housing. In this case, the diaphragm is particularly offset inward relative to the predetermined rupture area or at least the other diaphragms, so that the opening is covered by the two diaphragms on both sides. Therefore, the diaphragm is also protected by the diaphragm and prevented from hitting it by water (steam). Since the two diaphragms are arranged on both sides of the predetermined rupture area, the construction is also simplified, and the two diaphragms are suitably fixed to the battery housing in a fluid-tight manner. Alternatively to this, for example, the positions of the other diaphragms and the diaphragm are exchanged. In another alternative, the other diaphragms and the diaphragm are located on the same side relative to the battery housing / predetermined rupture area, and the diaphragm is particularly covered by the other diaphragms, so that the opening is also covered. In particular, the other diaphragms are offset outward relative to the diaphragm in this case, so that the diaphragm is protected by the other diaphragms. In this way, the area of ​​the other membrane for the passage of gas can also be selected to be relatively large. For example, the other membrane is fixed to this membrane and a laminate or sandwich structure is provided in particular through this membrane. In this way, production is simplified.

[0033] For example, the diaphragm is designed to be tear-resistant. However, the diaphragm is particularly preferably designed so that the diaphragm tears when the pressure difference between the pressure outside the battery housing and the pressure inside the battery housing exceeds a first limit value. Due to the tearing, the gas is accelerated through the diaphragm or at least the opening, so that the pressure in the battery housing is reduced relatively quickly. In this way, damage to the battery housing is avoided. For example, if the first limit value is exceeded, the diaphragm is completely torn and thus damaged, i.e. ruptured. Therefore, the entire area of ​​the opening is effectively used to allow gas to pass through, so that the pressure difference can be reduced relatively quickly. Alternatively or in combination with the tearing of the diaphragm, for example, when the first limit value or another limit value is exceeded, the fluid-tight connection between the diaphragm and the battery housing is at least partially removed. Therefore, gas is also allowed to escape there, which leads to a reduction in the pressure difference.

[0034] The first limit value is preferably less than the burst pressure representing the second limit value. Therefore, the predetermined rupture area is designed so that the predetermined rupture area ruptures when the pressure difference between the pressure outside the battery housing and the pressure inside the battery housing exceeds the second limit value, wherein the second limit value is greater than the first limit value. The first limit is, for example, between 90% and 50% of the second limit value (burst pressure), between 80% and 60% of the second limit value (burst pressure), and is, for example, substantially equal to 70% of the second limit value (burst pressure). Therefore, if the pressure increases excessively, the diaphragm is at least initially partially damaged, while, on the contrary, the predetermined rupture area remains intact. Therefore, the battery cell can continue to operate afterwards. On the other hand, if the pressure difference does not remain below the burst pressure despite the tearing of the diaphragm, the predetermined rupture area bursts, thereby preventing the battery housing from tearing at another location.

[0035] For example, the membrane is fastened to the outside of the battery housing, for example to the outside of the predetermined rupture area or possibly the substrate. In this way, the interior of the battery housing is not filled with the membrane, so that a relatively large volume is available there for the electrodes. 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 opening area. After the gas has passed through the opening, it therefore has an increased surface for passing through the membrane.

[0036] Preferably, the diaphragm rests on a stabilizing element having a plurality of additional openings on the side facing away from the battery housing. With the aid of the stabilizing element, in particular, the spatial freedom of the diaphragm is limited and the diaphragm is therefore additionally stabilized under increased pressure. In other words, the maximum deformation of the diaphragm is predetermined by the stabilizing element and the diaphragm is thus stabilized. Therefore, the stability of the diaphragm itself is not required, or at least the requirements for this are reduced, which is why there are no restrictions on the material selection of the diaphragm in this respect. The stabilizing element suitably covers the diaphragm completely. The stabilizing element is preferably designed to be rigid and, for example, is made of metal. In particular, the stabilizing element is designed in the manner of a grid, through which additional openings are thus formed. Due to the additional openings, the gas can pass through the stabilizing element without interference.

[0037] For example, the stabilizing element is designed such that it ruptures in the event of an increase in the pressure difference between the pressure inside the battery housing and the pressure outside the battery housing. The pressure difference at which this occurs can be set relatively accurately. Due to the rupture, the membrane is no longer stable and is therefore also overloaded, causing it to tear. As a result, a relatively large amount of gas can pass through this further opening. In this case, the pressure difference corresponds expediently to a possible first limit value.

[0038] For example, the stabilizing element is fixed to the battery housing at a distance from the predetermined rupture zone. In this way, damage to the predetermined rupture zone due to the connection of the stabilizing element to it is avoided during production, thereby reducing scrap and manufacturing costs. In this way, the predetermined rupture zone is also at least partially stabilized by the stabilizing element, which is why restrictions on the material selection or geometry of the predetermined rupture zone are reduced. Alternatively, the stabilizing element is fixed to the predetermined rupture zone. In this way, the space requirement is reduced.

[0039] In an alternative, the diaphragm is arranged on the inwardly directed side of the predetermined rupture zone. In other words, the diaphragm is located at an interior of the battery housing offset relative to the predetermined rupture zone. In this way, even at relatively high pressures in the battery housing, if it is not possible for gas to pass immediately due to the design of the diaphragm, the diaphragm will not bulge out excessively. In this case, the diaphragm is at least partially squeezed toward the inwardly directed side of the predetermined rupture zone. Therefore, the diaphragm is stabilized by the predetermined rupture zone, which increases the robustness. Even in the case of overpressure, the diaphragm is pressed against the predetermined rupture zone and thus prevents gas from passing between the predetermined rupture zone and the diaphragm, which increases the tightness in this area. Therefore, it is only possible for gas to escape through the diaphragm, which therefore occurs in a controlled manner.

[0040] For example, the diaphragm is fixed directly on the inwardly directed side of the predetermined rupture area. In this way, a relatively large-area connection of the diaphragm at the predetermined rupture area is also possible, thereby increasing the sealing in this area. However, it is particularly preferred that the diaphragm is partially supported on the predetermined rupture area via a spacer. Therefore, the diaphragm does not rest on the predetermined rupture area or only rests on the predetermined rupture area on the edge side, and is separated from the predetermined rupture area by a spacer in another area. Therefore, an increased diaphragm area is provided for gas passage, thereby increasing the volume of gas that can be guided through the diaphragm. For example, it is possible that a portion of the gas passes through the diaphragm into the space formed between the diaphragm and the predetermined rupture area defined by the spacer, and then reaches the surrounding environment of the battery cell through the opening. In summary, the diaphragm is not supported on the entire surface by the spacer, but only on a partial surface, that is, for example, in a point manner or in a specific area, so that a relatively large space is formed between the diaphragm and the predetermined rupture area.

[0041] The spacer is, for example, at least partially nail-shaped or tab-shaped, so that the diaphragm is also stabilized by them, so that the diaphragm will not be excessively deformed even under relatively large pressure differences. In this case, for example, the diaphragm is directly fixed to the battery housing on the edge side, or the diaphragm is supported on the battery housing, for example, at the predetermined rupture area, via another surrounding spacer on the edge side. The spacer is, for example, fixed at the predetermined rupture area. However, it is particularly preferred that the spacer is fixed to the diaphragm and is particularly molded on the diaphragm. Therefore, a fluid-tight connection is produced between the diaphragm and the spacer. Production is also simplified in this way. In particular, the spacer is made of the same material as the diaphragm, and these spacers are manufactured in a common working step, for example, in an injection molding or lamination method. In another alternative, the spacer and the diaphragm are separate components joined together during assembly. The fluid-tight fixation of the diaphragm at the predetermined rupture area is preferably carried out by a part of the spacer, particularly the spacer on the edge side. Alternatively thereto, the membrane can be fastened directly at the edge to the predetermined rupture region, wherein the membrane is spaced apart from the predetermined rupture region in other regions by a spacer.

[0042] For example, a possible matrix has other openings. In this case, the matrix is, for example, rigid, so that the battery cell is a prismatic cell. Alternatively to this, the matrix is ​​designed to be at least partially elastic and the battery cell is a soft pack cell. The bursting disk is inserted into the other opening so that the opening is closed by the bursting disk. The bursting disk is, for example, composed of a metal such as aluminum or a plastic. The bursting disk is a component separate from the matrix, which is fixed to the battery housing during assembly. In particular, the bursting disk is connected to the battery housing in an airtight and fluid-tight manner, preferably, for example, by welding and / or bonding. The bursting disk is, for example, circular and in particular substantially flat. In this case, the bursting disk is suitably arranged parallel to the possible side of the battery housing with other openings. Alternatively to this, the bursting disk is designed to be at least partially concave or convex, so that the compressive strength is thereby increased. The predetermined rupture area suitably includes a bursting disk. For example, the predetermined rupture area is formed by a bursting disk, or the predetermined rupture area also has another component. However, at least the bursting disk preferably includes an opening. In particular, the bursting disk ruptures when the bursting pressure is exceeded and the bursting disk is in particular selected accordingly. Due to the bursting disk, it is possible to use a prefabricated component, which is inserted into the further opening during assembly to provide a predetermined rupture point. Assembly is thus simplified. The bursting pressure can also be adapted to the respective application by selecting a corresponding bursting disk.

[0043] The diaphragm is suitably fixed to the bursting disk, for example, by bonding and / or welding. For example, ultrasonic, laser or temperature welding methods are used for this purpose. Since the diaphragm is fixed to the bursting disk, the composite can be produced separately and then the bursting disk with the diaphragm can be inserted into the other opening. In this way, assembly is simplified and subsequent damage to the bursting disk is essentially ruled out. In this way, a relatively low-cost fluidic connection of the diaphragm to the bursting disk is also achieved. In addition, in this way, a bursting disk with a diaphragm fixed thereto as a module can be manufactured, wherein the material properties of the diaphragm are already matched to the bursting disk. For example, one of a plurality of modules is used for a specific application.

[0044] Alternatively or in combination therewith, the wall thickness of the battery housing, preferably the possible base body, is reduced in the predetermined rupture region. In other words, the battery housing has a wall surrounding the predetermined rupture region. The wall is, for example, flat or rounded in this case. In the case, the thickness of the wall increases adjacent to the predetermined rupture region. In particular, the thickness of the wall or all walls of the battery housing is constant except for the predetermined rupture region, and the predetermined rupture region is surrounded on the edge side by a step in particular. The wall thickness of the battery housing in the predetermined rupture region is particularly adapted to the bursting pressure. For example, the battery housing has been formed in the predetermined rupture region with a reduced wall thickness. Alternatively to this, in order to produce the predetermined rupture region, material is stripped from one of the walls of the battery housing, for example by milling or laser. For example, the wall thickness is constant in the predetermined rupture region. Alternatively to this, the wall thickness varies in the predetermined rupture region so that when the bursting pressure is exceeded, a specific type of tearing occurs in the predetermined rupture region. For example, the predetermined rupture region is formed only by reducing the wall thickness. Alternatively to this, the predetermined rupture region also has other components, such as a bursting disk. However, at least the opening is preferably located in a region of the battery housing in which the wall thickness is reduced.

[0045] Alternatively, the battery housing has one or more notches in the predetermined rupture region. Through (these) notches, at least part of the material of the battery housing, preferably the base body, is removed, so that the notches constitute the desired structural weakening of the battery housing, for example the base body. If the bursting pressure is exceeded, the battery housing will tear in the region of the one or more notches, resulting in material escaping from the battery housing.

[0046] For example, (these) recesses are introduced after the battery housing, in particular the formation of the matrix. In this way, production becomes easier. For example, the recess is designed to be closed in this case and is therefore particularly shaped as a ring type. Alternatively to this, the recess is designed to be elongated and has two ends spaced apart from each other. In another alternative, these recesses or at least a portion of the recesses are point-shaped and designed in a perforated manner. For example, the predetermined rupture area includes a plurality of recesses designed as rings or circles. These are, for example, arranged concentrically with the opening, so that the opening is surrounded by the recess. For example, in addition to the recess / these recesses, the wall thickness of the battery housing is reduced in area in the predetermined rupture area. In this way, the bursting pressure can be adjusted relatively accurately, wherein production is simplified.

[0047] In particular, the outer contour of the predetermined rupture region is defined by the one or more notches. In other words, all or at least some of the notches extend along the outer contour (i.e. the boundary) of the predetermined rupture region. Therefore, when the bursting pressure is exceeded, the predetermined rupture region is torn along its outer contour, so that in particular the entire predetermined rupture region is released. A relatively fast equalization of the pressure difference is thus performed. For example, further notches are additionally present in the predetermined rupture region, so that only relatively small fragments are generated when tearing / rupturing. Therefore, damage to other components due to these fragments is excluded.

[0048] The battery cell particularly preferably comprises a drying element. The drying element is used in particular to reduce moisture penetrating into the battery housing through other openings. The drying element is suitable for this, in particular is provided and set up for this purpose. Due to the drying element, the penetrating moisture, for example water (steam), is bound up, thereby preventing undesired reactions with electrodes and / or possible electrolytes arranged in the battery housing. The operating reliability is thus further increased. In particular, the drying element is designed to bind water, in particular to absorb water molecules, by means of it. Suitably, the drying element comprises a silicate or is formed by a silicate. In this way, the drying effect is further improved.

[0049] Preferably, the drying element surrounds the opening. In this way, the drying effect in the region of the fluidic connection between the interior and the exterior of the battery housing is improved. The drying element is therefore preferably designed in the form of a hollow cylinder, which makes production easier. For example, the drying element is located on the outside or inside of the predetermined rupture region in this case. Preferably, the drying element is offset to the interior of the battery housing compared to the membrane, so that moisture penetrating into the battery housing despite the membrane is prevented by the drying element.

[0050] The invention also relates to a composite of such a battery cell, wherein the composite is preferably a battery module or a high-voltage battery. The invention also relates to a motor vehicle, such as a passenger car (PKW), having such a battery cell, in particular such a composite. The battery cell is used in particular for supplying power to a main drive of a motor vehicle.

[0051] The advantages and embodiments described in connection with the battery cells can also be transferred in a practical manner to the combination / motor vehicle and to one another, and vice versa. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The embodiments of the present invention are explained in more detail below with reference to the accompanying drawings, wherein:

[0053] Figure 1 A schematically simplified illustration of a motor vehicle having a plurality of battery cells of identical construction;

[0054] Figure 2 One of the battery cells having a cell housing with a predetermined rupture area is schematically shown in cross-section;

[0055] Figure 3 A battery housing is shown in perspective, partially in cross-section, wherein the predetermined rupture area comprises a bursting disk;

[0056] Figure 4-7 Each schematically and partially shows a variant of a battery housing in a cross-sectional view, in which the predetermined rupture region has an opening covered with a gas-permeable membrane, and

[0057] Figure 8 , Fig. 9 Further variants of the battery housing are shown schematically in each case in perspective, partially in section.

[0058] In all the figures, parts that correspond to one another are provided with the same reference symbols. DETAILED DESCRIPTION

[0059] In all the figures, parts that correspond to one another are provided with the same reference symbols.

[0060] exist Figure 1In the figure, a motor vehicle 2 in the form of a passenger car (Pkw) is schematically simplified. The motor vehicle 2 has a plurality of wheels 4, at least some of which are driven by a drive device 6 comprising an electric motor. The motor vehicle 2 is therefore an electric vehicle or a hybrid vehicle. The drive device 6 has an inverter, via which the electric motor is supplied with power. The inverter of the drive device 6 is in turn supplied with power by an energy storage device 8 in the form of a high-voltage battery pack. For this purpose, the drive device 6 is connected to an interface 10 of the energy storage device 8, which interface 10 is introduced into an energy storage device housing 12 of the energy storage device 8 made of stainless steel.

[0061] A plurality of battery modules of identical structure to each other, not shown in detail, are arranged in the energy storage housing 12 of the energy storage device 8, and each of the battery modules includes a plurality of battery cells 14. The battery cells 14 of each battery module are partially connected in series and partially connected in parallel to each other. Some of the battery modules are also connected in series, and these battery modules are also connected in parallel to each other. The electrical connection of the battery module is electrically contacted with the interface 10, so that the battery module and therefore also the battery cells 14 are discharged or charged (recycled) when the drive device 6 is running. Due to the electrical connection, the voltage provided at the interface 10 (which is 400V) is several times the voltage provided by each of the battery modules and also by each of the battery cells 14.

[0062] exist Figure 2 , one of the battery cells 14 of identical structure is shown 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 flat and are alternately stacked one above the other to form a battery stack, wherein a separator not shown in detail is arranged between the respectively adjacent anodes 16 and cathodes 18. The anode 16 protrudes beyond the cathode 18 on a common side, i.e., the respective current collector, which is formed by the respective metal foil. In the region of the protrusion, the respective current collector has no components, but in other regions, the following layers are applied on the respective current collector, which is also referred to as a carrier, and the current collector 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 the anode 16 and the cathode 18.

[0063] The projections of the anode 16 and cathode 18 are welded to the associated busbars 22 made of copper, respectively. In this case, one of the busbars 22 is assigned to the anode 16 and cathode 18, respectively. These busbars 22 each have a connection end 24, which is guided through a base body 26 of a battery housing 28, in which the anode 16 and cathode 18 are arranged. The electrodes 20 are therefore arranged in the battery housing 28. The base body 26 is designed to be rigid and is made of aluminum. The battery cell 14 is therefore a prismatic cell. The base body 26 and therefore the battery housing 28 are filled with a liquid electrolyte (not shown).

[0064] The battery housing 28 comprises a predetermined rupture region 30, the area of ​​which is 5 cm 2. The predetermined rupture region 30 is designed so that it ruptures when the pressure difference between the pressure outside the battery housing 28 (i.e. the base body 26) and the pressure inside the battery housing 28 (i.e. the base body 26) exceeds a bursting pressure of 1 bar, so that the battery housing 28 opens and pressure equalization can be performed. The bursting pressure is 90% of the maximum pressure load of the base body 26, i.e. 90% of the pressure difference at which irreversible and uncontrolled damage to the base body 26 occurs. The bursting pressure constitutes the second limit value in this case.

[0065] exist Figure 3 , a battery housing 28 with a cuboid base 26 is shown in detail in a perspective view. A further opening 32 in the shape of a stadium is introduced into the base 26, which is closed by a bursting disk 34 of the battery housing 28. In other words, the bursting disk 34 is inserted into the further opening 32, wherein the edge of the bursting disk 34 overlaps the edge of the further opening 32 and is fixed thereto in a fluid-tight and gas-tight manner by welding. The battery housing 28 is designed so that the base 26 and the bursting disk 34 are flush with each other on the outside. The predetermined rupture area 30 is determined by the bursting disk 34, so that the predetermined rupture area 30 includes the bursting disk 34. Here, the size of the further opening 32 is equal to the size of the predetermined rupture area 30. When the bursting pressure is exceeded, the bursting disk 34 is completely torn or ruptured, thereby releasing the further opening 32.

[0066] The bursting disk 30 is made of aluminum and has a reduced thickness compared to the wall thickness of the battery housing 26. The other openings 32 are located in the same wall of the base body 26, wherein the slit for one of the connectors 24 is also introduced into this wall. Apart from the other openings 28, the base body 26 is designed to be fluid-tight and gas-tight. The area between the connector 24 and the associated slit in the base body 26 is filled with plastic (not shown in detail).

[0067] exist Figure 4, a battery cell 14 is schematically shown in a partial cross-sectional view. The bursting disk 34 and therefore the predetermined rupture area 30 also have a circular opening 36 in the middle thereof. The area of ​​the opening 36 is reduced by 1 mm2 compared to the other openings 32. The opening 36 is covered with a gas-permeable membrane 38, which at least partially consists of PTFE and has a crystallinity between 85% and 100% and a density between 0.2 g / cm3 and 2 g / cm3. Therefore, the gases H2 and CO2 pass through the membrane 38 relatively easily, while the passage of moisture, that is, in particular water vapor, is comparatively more difficult. The area of ​​the membrane 38, which is arranged concentrically with the opening 36 and is also designed to be circular, is three times the area of ​​the opening 36 in this embodiment.

[0068] The membrane 38 is arranged on the inwardly directed side 40 of the bursting disk 34 and therefore on the inwardly directed side of the predetermined rupture region 30. In other words, the membrane 38 is located inside the base body 26 relative to the bursting disk 30 and the further predetermined rupture region 30 and is therefore also offset into the battery housing 28. A tab-shaped spacer 42 is arranged between the membrane 38 and the bursting disk 34, by which the membrane 38 is partially supported on the bursting disk 34 and therefore also on the predetermined rupture region 30. In other words, the membrane 34 is spaced apart from the predetermined rupture region 30, namely by the thickness of the spacer 42.

[0069] One of the spacers 42 is arranged on the edge of the diaphragm 38 and is designed to be circumferential, so that it is circular or annular. This spacer 42 is gas-tight and liquid-tight, i.e. fluid-tight, i.e. fixed to the bursting disk 34 by laser welding. On the other hand, the other spacers 42 only rest loosely on the bursting disk 34 and thus, unlike the annular spacer 42, do not surround a complete spatial region on the circumferential side. All spacers 42 are molded on the diaphragm 38 and are made of the same material and in the same processing steps.

[0070] The diaphragm 38 is designed so that the diaphragm 38 tears when the pressure difference between the pressure outside the battery housing 28 and the pressure inside the battery housing 28 exceeds a first limit value. The first limit value is 50% lower than the burst pressure, i.e., the second limit value. Once the tearing has started, this situation will continue until the pressure difference drops below the first limit value. When this is the case, the tearing will stop.

[0071] The opening 36 is covered by a further membrane 44, which is arranged outside the bursting disk 34 and therefore also outside the predetermined rupture area 30. The further membrane 44 is therefore offset outwards relative to the bursting disk 34 / predetermined rupture area 30 and the opening 36 is covered on each side by one of the membranes 38, 44, respectively. However, the further membrane 44 is additionally designed to be air-permeable but also hydrophobic. In other words, water is blocked by the further membrane 44. The further membrane 44 is also fixed to the bursting disk 34 in a fluid-tight manner.

[0072] During operation of the battery cell 14, gases such as H 2 and / or CO 2 may form in the battery housing 28 due to undesired chemical reactions, for example due to relatively high loads or due to unexpected foreign particles. The gas 36 requires a larger volume than the reactants, so that the pressure inside the battery housing 28 increases. As a result, the pressure inside the battery housing 28 increases compared to the outside of the battery housing 28. In other words, the pressure of the surroundings of the battery housing 28 is lower than the pressure inside the battery housing 28. Therefore, the gas or at least part of the gas is discharged through the diaphragm 38 and through the opening 36 and other diaphragms 44 into the surroundings of the battery cell 14, so that pressure equalization occurs. Due to the large area of ​​the diaphragm 38, a larger volume of gas can be discharged. A part of it passes through the area of ​​the diaphragm 38 covered by the bursting disk 34. Subsequently, for this part, there is no further fluidic resistance for passing through the opening 36, because no space is completely closed except for the outermost spacers 42. In other words, the further flow of gas is not hindered by these spacers 42. By means of the outermost spacer 42 , gases or other fluids are prevented from flowing out of or into the battery housing 28 between the bursting disk 34 and the membrane 38 without passing through the membrane 38 .

[0073] The gas flowing out through the opening 36 passes through the further membrane 44 and thus escapes. In this case, the membrane 44 prevents liquid or gaseous water and water vapor from penetrating into the opening 36 and thus also into the interior of the battery housing 28. If moisture still reaches the membrane 38, it is blocked by the membrane 38, which has a relatively high impermeability to moisture. Moisture from outside the battery housing 28 is thus prevented from entering the battery housing and causing undesired reactions with the electrode 20 there.

[0074] If, due to special circumstances, such as excessive load, the volume of gas passing through the diaphragm 38 is not sufficient to limit the pressure difference to below 0.5 bar (i.e. the first limit value), the diaphragm 38 begins to tear. As a result, a larger volume of gas can pass, so that the pressure increase is limited or at least slowed down. If this is sufficient to eliminate the pressure difference, then further operation of the battery cell 14 is also possible, wherein the penetration of moisture from the outside into the battery housing 28 is only partially blocked by the diaphragm 38. Alternatively or in combination with the tearing of the diaphragm 38, when the pressure difference is greater than the first limit value, the fluid-tight connection of the outermost spacer 42 on the bursting disk 34 also begins to decompose, so that gas can also escape there, until the opening 36 and from there into the surrounding environment. If, in the case of complete tearing / separation of the diaphragm 38, i.e. when all openings 36 except the other diaphragms 44 are completely released, the pressure increase is also unrestricted and exceeds the bursting pressure, i.e. the second limit value, the bursting disk 34 will rupture, so that the other openings 32 are released. As a result, the gas volume that can be discharged from the battery housing 28 is further increased, wherein in this case there is essentially no fluid resistance. The pressure difference is thus reduced relatively quickly and uncontrolled damage to the base body 26 is thus prevented, which could lead to damage to objects arranged in the surroundings of the battery cell 14. However, electrolyte can also be discharged from the further openings 32, so that the battery cell 14 is no longer available for use.

[0075] Figure 5 , a variant of the battery cell 14 is shown in which the other openings 32 and the position of the bursting disk 34 and its fixing on the base body 26 are not changed. The bursting disk 34, i.e. the predetermined rupture area 30, also has an opening 36 which is likewise unchanged. However, in this embodiment, the bursting disk 34 is made of a polymer and the thickness of the bursting disk 34 is adapted so that it also ruptures at a bursting pressure of 1 bar. The opening 36 continues to be completely covered by the diaphragm 38, which is arranged offset to the interior of the base body 26 relative to the bursting disk 34. The material of the diaphragm 38 is also unchanged. However, the area of ​​the diaphragm 38 is slightly reduced and it is mechanically placed directly on the bursting disk 34, i.e. the predetermined rupture area 30, and fixed thereto, i.e. by ultrasonic welding. As a result, a fluid-tight connection is directly achieved between the diaphragm 38 and the predetermined rupture area 30.

[0076] Compared to the previous embodiment, the further membrane 44 is also omitted and the opening 36 is surrounded by an annular or hollow cylindrical drying element 46, which is hydrophilic and made of silicate. Therefore, with the exception of the membrane 38, the opening 36 is not covered. With the help of the drying element 46, water and thus water vapor that hit the predetermined rupture area 30 in the area of ​​the opening 36 from the outside are absorbed so that it does not reach the opening 36. Therefore, the penetration of moisture into the battery housing 28 is prevented or at least reduced by the drying element 46. During the operation of the battery cell 14, the drying element 46 is at least partially heated due to heat losses, so that possible absorbed moisture is released again into the surrounding environment and transported away. Therefore, the drying element 46 is ready for use for a relatively long period of time. Compared with the previous design, the working mode of the membrane 38 and the bursting disk 34 has not changed. However, in this variant, the effective area provided by the membrane 38 for the gas to pass through the opening 36 is equal to the area of ​​the opening 36. In other words, the gas volume that can pass through the membrane 36 is reduced. In this variant of the battery cell 14 , the pressure increase in the cell housing 28 until the membrane 38 tears or the bursting disk 34 ruptures is therefore reduced or limited only to a small extent.

[0077] Figure 6 Another variant of the battery cell 14 is shown, in which the battery housing 26 and the other openings 32 closed by means of the bursting disk 34 are unchanged. The bursting disk 34 and thus the predetermined rupture region 30 still have an opening 36. The membrane 38 is again present, wherein the extension of the membrane 38 corresponds substantially to Figure 3 However, the membrane 38 is now fixed on the edge side on the opposite side of the bursting disk 30, that is to say on the outer side 48 of the battery housing 28, i.e. on the outwardly directed side of the predetermined rupture area 30, i.e. by means of heat welding. Otherwise, the membrane 38 is not fixed on the bursting disk 34 and only rests loosely on the bursting disk 34 in other areas.

[0078] The battery cell 14 also has a stabilizing element 50, by which the diaphragm 38 is completely covered and which protrudes slightly beyond the diaphragm 38 on the edge side. Therefore, the diaphragm 38 rests on the outside at the stabilizing element 50 made of metal. In the edge area of ​​the stabilizing element 50, it is designed to be continuous and is welded to the predetermined rupture area 30, i.e. the bursting disk 34, and is therefore connected thereto in a fluid-tight manner. Apart from the edge, the stabilizing element 50 is designed in a grid-like manner and therefore has a large number of additional openings 52.

[0079] When the battery cell 14 is in operation, any gases that may be generated first pass through the opening 36 and then through the diaphragm 38 and the additional opening 52 into the surrounding environment. Due to the loose placement of the diaphragm 38 on the bursting disk 34, in addition to the fixation on the edge side, gas may accumulate in the area formed between the diaphragm 38 and the bursting disk 34, so that a relatively large area of ​​the diaphragm 38 is available for the passage of gas. In this case, the diaphragm 38 partially bulges outward, wherein excessive bulging is prevented by the stabilizing element 50. Therefore, a corresponding bulge of the diaphragm 38 is generated in each of the additional openings 52. Due to the bulge or bulge, the area of ​​the diaphragm 38 that can be used for the passage of gas is further increased. However, excessive deformation of the diaphragm 38 is prevented by the stabilizing element 50, thereby avoiding damage to the diaphragm 38. The mechanical connection of the diaphragm 38 to the bursting disk 34 is also stabilized by the stabilizing element 50, thereby preventing the diaphragm 38 from being torn off the bursting disk 34.

[0080] If the pressure difference between the pressure inside the battery housing 28 and the pressure outside the battery housing 28 exceeds a first limit value, the stabilizing element 50 is at least partially ruptured, so that the stabilizing function of the membrane 38 is released. As a result, the membrane 38 tears, which is why the gas that may have increased in volume can continue to escape.

[0081] Figure 7 4 shows a further variant of a battery cell 14. This variant corresponds essentially to the previous embodiment, but the stabilizing element 50 is covered on the outside by a further membrane 44. The stabilizing element 50 is therefore located between the two membranes 38, 44. The further membrane 44 prevents moisture from penetrating into the additional opening 52 and thus into the membrane 38, wherein, however, gases can still escape from the battery housing 28.

[0082] In a variant not shown in detail, instead of or in addition to the further membrane 44 , a drying element 46 is present, by which the stabilizing element 50 is surrounded or which lies on the edge of the stabilizing element 50 so that the opening 36 is surrounded by it.

[0083] In a variant not shown in detail, either Figure 6 In the implementation method, either Figure 7 In the embodiment of , there is no stabilizing element 50 and the diaphragm 38 is designed to be more stable. When gas accumulates between the diaphragm 38 and the bursting disk 34, the diaphragm 38 is thus relatively greatly bulged, wherein tearing is avoided. This only occurs when the first limit value is exceeded.

[0084] Figure 8 and Fig. 9, a variant of a battery cell 14 is shown in which the predetermined rupture region 30 is respectively modified. It also has an opening 36 which is covered by a membrane 38. In the variant shown, the membrane 38 is respectively fixed to the outer side 48 of the battery housing 28, namely by welding. In the two variants shown, there is neither a further membrane 44 nor a drying element 46 or a stabilizing element 50. However, in a variant not shown in detail, the battery cell 14 is provided according to Figure 4-7 The variant shown is extended in that the predetermined rupture zone 30 is based on Figure 8 and 9 The embodiment shown is designed.

[0085] exist Figure 8 In the variant shown, the wall thickness of the battery housing 28 (i.e., the base body 26) is reduced in the predetermined rupture region 30. The predetermined rupture region 30 is molded on the base body 26 and is integral with it. However, compared with the base body 26, in the predetermined rupture region 30, the wall thickness is reduced to 25%, so that the predetermined rupture region 30 is separated from the base body 46 by the surrounding step 54. In other words, the step 54 forms a transition from the predetermined rupture region 30 to the base body 26. The wall thickness in the predetermined rupture region 30 is constant in this case. The predetermined rupture region 30 is designed to be circular and is arranged concentrically with the opening 36.

[0086] In order to produce the predetermined rupture region 30, material is removed from the produced base body 26 with continuous wall thickness, for example by milling or by using a laser, to form the predetermined rupture region 30. In the variant shown, the material removal is carried out from the inside, so that the outside of the battery housing 28 is flat. In this way, the fixing of the membrane 38 becomes easier.

[0087] exist Fig. 9 In the variation shown in , the predetermined rupture region 30 has substantially the same wall thickness as the substrate 26, and the predetermined rupture region 30 is also formed integrally with the substrate 26. The predetermined rupture region 30 is separated from the substrate 26 by a surrounding notch 56. The notch is also introduced into the substrate 28 after completion to produce the predetermined rupture region 30. Therefore, the outer contour of the predetermined rupture region is defined by the notch 56. The notch 56 is annular and arranged concentrically with the opening 36. In addition, the predetermined rupture region 30 has such other notches 56, which are also annular but have a reduced diameter. Therefore, the predetermined rupture region 30 includes these two notches 56 arranged concentrically with the opening 36, which represent a structural weakening of the battery housing 26.

[0088] Also there Figure 8 and Fig. 9In the case of the variant of the predetermined rupture region 30 shown in FIG, the battery housing 28 is weakened by reducing the wall thickness or the recess 56 so that the predetermined rupture region 30 ruptures when the bursting pressure is exceeded, thereby allowing an increased volume of gas to escape from the battery housing 26. Here too, uncontrolled damage to the base body 26 in the event of an increase in pressure is avoided.

[0089] The present invention is not limited to the above exemplary embodiments. On the contrary, those skilled in the art can also derive other variations of the present invention without departing from the subject matter of the present invention. In particular, all the individual features described in conjunction with the various embodiments can also be combined in other ways without departing from the subject matter of the present invention.

[0090] Reference numerals list

[0091] 2 Motor Vehicles

[0092] 4 wheels

[0093] 6 Drive device

[0094] 8 Energy storage device

[0095] 10 Interface

[0096] 12 Energy storage housing

[0097] 14 Battery Cells

[0098] 16 Anode

[0099] 18 Cathode

[0100] 20 Electrodes

[0101] 22 Bus

[0102] 24 Connection terminal

[0103] 26 Matrix

[0104] 28 Battery housing

[0105] 30 Predetermined rupture area

[0106] 32 Other openings

[0107] 34 Bursting Disk

[0108] 36 Opening

[0109] 38 Diaphragm

[0110] 40 Inward directional side

[0111] 42 Spacer

[0112] 44 Other diaphragms

[0113] 46 Drying element

[0114] 48 outside

[0115] 50 Stabilizing elements

[0116] 52 Additional openings

[0117] 54 steps

[0118] 56 Notch

Claims

1. A battery cell (14) having a cell housing (28), in which a plurality of electrodes (20) are arranged, and wherein the cell housing has a predetermined rupture region (30), wherein the predetermined rupture region (30) has an opening (36) which is covered by a gas-permeable membrane (38).

2. The battery cell (14) according to claim 1, characterized in that The membrane (38) is designed such that the membrane (38) tears when a pressure difference between a pressure outside the battery housing (28) and a pressure inside the battery housing (28) exceeds a first limit value.

3. The battery cell (14) according to claim 2, characterized in that The predetermined rupture region (30) is designed so that when the pressure difference between the pressure outside the battery housing (28) and the pressure inside the battery housing (28) exceeds a second limit value, the predetermined rupture region (30) ruptures, wherein the second limit value is greater than the first limit value.

4. The battery cell (14) according to any one of claims 1 to 3, characterized in that The membrane (38) is fixed to the outer side (48) of the battery housing (28).

5. The battery cell (14) according to claim 4, characterized in that The membrane (38) rests on a side facing away from the battery housing (26) on a stabilizing element (50) having a plurality of additional openings (52).

6. The battery cell (14) according to any one of claims 1 to 3, characterized in that The membrane (38) is arranged on an inwardly directed side (40) of the predetermined rupture zone (30), wherein the membrane (38) is supported partially on the predetermined rupture zone (30) via a spacer (42).

7. The battery cell (14) according to any one of claims 1 to 6, characterized in that The battery housing (28) includes a base body (26) having a further opening (32) into which a bursting disk (34) is inserted, wherein the predetermined rupture area (30) includes a bursting disk (34).

8. The battery cell (14) according to any one of claims 1 to 7, characterized in that The wall thickness of the battery housing (28) is reduced in the predetermined rupture region (30).

9. The battery cell (14) according to any one of claims 1 to 8, characterized in that The battery housing (28) has a recess (56) in the predetermined rupture region (30), by which the outer contour of the predetermined rupture region (30) is delimited.

10. The battery cell (14) according to any one of claims 1 to 9, characterized in that The opening (36) is surrounded by a drying element (46).

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