Thermal protective assembly for a cell housing and battery cell

Abstract

The invention relates to an assembly for thermally reinforcing a cell housing of a battery cell, having a cell housing with an inner volume and having at least one electrode stack which is arranged in the inner volume of the cell housing, wherein the cell housing is thermally reinforced at least in some regions and / or is insulated at least in some regions with respect to the electrode stack. Moreover, the invention relates to a battery cell having an assembly.

Description

[0001] THERMAL PROTECTION ARRANGEMENT FOR A CELL HOUSE AND BATTERY CELL

[0002] The invention relates to an arrangement for the thermal reinforcement of a battery cell housing, comprising a cell housing with an internal volume and comprising at least one electrode stack arranged in the internal volume of the cell housing. The invention further relates to a battery cell with such an arrangement.

[0003] Battery cells based on the electrochemical principle are typically used for storing and providing electrical energy. Lithium-ion battery cells are commonly used, particularly in the automotive sector. For reasons of weight and cost, these battery cells have aluminum casings. Inside the casing is an electrode stack or coil, consisting of anode foils, cathode foils, and separators. An electrolyte is also typically present within the cell casing.

[0004] In the event of overcharging or a short circuit, a battery cell can undergo an exothermic reaction (so-called thermal runaway). This reaction generates not only heat from the chemical reaction but also gases that must be vented from the battery cell to prevent explosions. Burst membranes are used for this purpose; these are, for example, attached to the outside of a cell cover of the battery cell casing. A rupture membrane can open when a predefined pressure is exceeded within the cell casing, thus creating a connection to the external environment. Burst membranes are already known in the form of pressure relief valves, targeted weakenings in cell casings, or targeted weakenings in plates connected to the cell casing.

[0005] However, the high temperature of the resulting gases in the event of thermal runaway is problematic, as it can exceed 1,000°C in cell chemistry with high specific energy density. Such high temperatures can result in partial or complete destruction of the cell casing and thus also impair the mechanical stability of the battery cell.

[0006] The present invention therefore aims to provide an arrangement and a battery cell that can improve the mechanical stability of the battery cell in the event of thermal runaway. This objective is achieved by the features specified in claim 1. Further advantageous embodiments of the invention are part of the dependent claims and the description.

[0007] According to one aspect of the invention, an arrangement for the thermal reinforcement of a battery cell housing is provided. The arrangement comprises a cell housing with an internal volume and at least one electrode stack. Depending on the embodiment, the electrode stack can also be configured as an electrode winding and may include several anode foils, cathode foils, and separator foils.

[0008] The electrode stack is arranged within the internal volume of the cell housing and may also comprise a solid or liquid electrolyte. According to the invention, the cell housing is at least partially thermally reinforced and / or is at least partially insulated from the electrode stack, particularly thermally.

[0009] The thermal insulation and / or thermal reinforcement of the cell housing and / or the thermal insulation of the cell housing from the electrode stack can be implemented as a permanent reinforcement or insulation or as a temporary reinforcement or insulation, in which the corresponding insulating and / or reinforcing effect can be activated in the event of thermal runaway or can gradually decrease due to the action of heat.

[0010] According to a further aspect of the invention, a battery cell is provided which has the arrangement according to the invention. The battery cell can have one or more electrode stacks or electrode windings, which consist of anode foils or layers, cathode foils or layers, and separator foils or layers. The electrode stack is arranged in the inner volume of the cell housing, which may have at least one rupture membrane. The cell housing can be closed by at least one cell cover, which includes one or more terminals that electrically connect the respective anode foils and cathode foils.

[0011] The arrangement according to the invention enables a thermally effective reinforcement of the cell housing, which can be implemented, for example, across the entire surface or for the entire cell housing. The thermally effective reinforcement can be designed with a uniform material thickness or with a variable material thickness depending on the temperature.

[0012] Alternatively or additionally, thermal reinforcement of the cell casing can be implemented, which is carried out only partially. For example, such reinforcement can be provided only in the area of ​​the rupture membrane or in the area of ​​a relatively thin wall of a cell casing shell.

[0013] The cell casing can therefore be reinforced completely or partially with a higher melting point material.

[0014] The cell casing is preferably formed by a cell casing shell and at least one cell lid. Depending on the embodiment, the cell casing shell can have two openings, which can be closed by two cell lids. The cell casing shell has multiple walls. Depending on the embodiment, the at least one cell lid can serve as a wall of the cell casing and thus also be thermally reinforced and / or insulated.

[0015] The thermal reinforcement or thermal insulation of the cell housing relative to at least one electrode stack can be implemented with a constant or variable thickness. For example, the thickness of the reinforcement and / or insulation can be temperature-dependent. Areas of the cell housing subjected to higher thermal stress during thermal runaway can preferably have a greater layer thickness than areas of the cell housing subjected to lower thermal stress. Such areas of the cell housing and their thermal stress can be easily determined using experimental tests or CFD simulations. For example, an area adjacent to the rupture membrane can be defined as an area subjected to higher thermal stress.

[0016] Alternatively or additionally, the arrangement can achieve full or partial shielding or insulation of the cell housing from heat exposure. This protects the cell housing wall, made of aluminum or another material, from overheating and subsequent melting.

[0017] The melting behavior of the cell casing wall can be optimized, or melting delayed or prevented, at least in certain areas, if the cell casing is thermally reinforced by a material that is bonded to the casing, at least in certain areas. Preferably, the material is located on the inside and / or outside. "Inside" or "outside" refers, for example, to an internal volume that is sealed by the cell casing. For instance, one or more high-melting-point metals, such as stainless steel, nickel, steel, and the like, can be used as the material on the inside or within the internal volume, or on the outside or outside the internal volume of the cell casing, to improve the thermal and mechanical stability of the cell casing. This measure can prevent or at least delay the exposure of cell contents within the internal volume of the cell casing due to melting of the cell casing wall.

[0018] The material can be bonded to the cell housing partially or across its entire surface. A full-surface bond between the material and the cell housing can be achieved, for example, through plating. In this case, the entire cell housing could, for instance, consist of aluminum clad with stainless steel.

[0019] The plating, or the plated areas, of the cell housing can be applied before the cell housing is manufactured, for example, onto a prepared or cut-to-length sheet. Depending on the design, a completely clad sheet can also be used for manufacturing the cell housing. Such a sheet can be cut to size, folded, and then used as one or more walls of the cell housing to form an internal volume that is at least partially open.

[0020] The cell casing can consist of a cell casing shell and at least one cell cap. The cell casing shell can have one or more openings into which the cell cap can be inserted.

[0021] The connection between the cell walls and / or the cell casing shell and the cell lid can be achieved by crimping, gluing, soldering, welding, or similar methods. The cell casing, or its internal volume, can be closed by one or more cell lids.

[0022] The described plating can be carried out with a metal that has a higher melting point than aluminum, such as steel, stainless steel, nickel, and the like. Due to the otherwise possible risk of electrocorrosion, these metals are preferably applied externally or outside the internal volume. In a further embodiment, the reinforcing element is designed as a reinforcing insert, which is arranged in a rupture opening and / or forms a boundary around the rupture opening. The reinforcing element can project at least partially into the rupture opening, thus protecting a wall of the opening. Depending on the design, the reinforcing element can have an opening corresponding to the rupture opening, which are positioned one above the other when assembled. This allows the reinforcing element to strengthen or thicken the wall surrounding the rupture opening.

[0023] According to another embodiment, the cell casing is thermally reinforced by thickening at least one wall, at least in certain areas. This measure enables a technically simple reinforcement of the cell casing.

[0024] According to one embodiment, the cell housing is thermally reinforced by a coating applied at least in certain areas. In one embodiment, the coating is applied to the inside and / or outside of at least one wall of the cell housing. The coating can, for example, be in the form of a ceramic or a higher-melting-point metal.

[0025] A higher melting point metal can be any metal or metal alloy that has a higher melting point than aluminum. For example, the coating could be made of steel, stainless steel, nickel, and the like. Possible ceramic coatings include, for example, Al₂O₃, SisN₄, and similar materials.

[0026] The cell housing can be particularly efficiently shielded against temperature changes in the electrode stack if the cell housing is thermally reinforced by at least one internal and / or external reinforcing element. An internally arranged reinforcing element can, for example, be an insert element designed as a sheet, a strip, a molded part, or the like.

[0027] The reinforcing element can be attached to the cell casing and / or the electrode stack, for example, by a material-bonded connection, a force-bonded connection, a form-bonded connection, a local thickening or thickening of the cell casing, and the like.

[0028] In the case of an external arrangement of the reinforcing element, it can also be attached to the cell casing by a material-bonded connection, a force-bonded connection, a form-bonded connection, a local thickening of the cell casing, and the like.

[0029] The reinforcing element can be fixed in place by a material bond, for example, in the form of a surface weld, to prevent hot gas from penetrating underneath it during thermal runaway. Alternatively or additionally, the reinforcing element can be fixed by frictional or form-fitting means. This can be achieved, for example, by clamping, crimping, clinching, riveting, and similar methods.

[0030] Because the reinforcing element can be attached to the cell casing without a metallurgical bond, it can be made of thermally resistant and typically non-weldable materials, such as ceramics, carbon, and the like. The reinforcing element can be a solid material, a fiber mat, a felt, or a nonwoven fabric.

[0031] In another embodiment, the reinforcing element is fixed to the cell housing by a rupture membrane. The rupture membrane can be directly or indirectly connected to the cell housing and act as a connecting element between the housing and the reinforcing element. This measure allows for indirect fixing of the reinforcing element to the cell housing via the rupture membrane. This eliminates the need for additional components for fixing the reinforcing element, thus effectively reducing the number of components.

[0032] In a further embodiment, at least one thermally insulating plate is arranged between at least one wall of the cell housing and the at least one electrode stack. Preferably, the cell housing is insulated from the electrode stack, at least in some areas, by the thermally insulating plate. This allows a thermally resistant plate to be positioned as a heat shield between the electrode stack and the wall of the cell housing to achieve targeted protection against thermal stress. Such a plate can, for example, be made of a thermally insulating material, such as ceramic or carbon, and / or of a material with a higher melting point than aluminum.

[0033] The detachment of fibers or particles from the electrode stack during thermal runaway of a battery cell can be prevented particularly effectively if the at least one electrode stack arranged within the internal volume of the cell casing is at least partially encased by a thermally insulating mat. Such a mat can advantageously be gas-permeable. This insulates the cell casing, at least partially, from the electrode stack. This measure also provides thermal insulation of the electrode stack, which serves as a heat source during thermal runaway, from the cell casing.

[0034] According to a further embodiment, the thermally insulating mat is designed as a ceramic fiber mat. Such a mat can, for example, be a ceramic fiber mat impregnated with a thermoplastic, such as polypropylene, or a ceramic nonwoven fabric. For example, Al₂O₃ or SisN₄ can be used as the ceramic material. The insulating mat can also function as a filter if the cell housing has at least one rupture membrane and the thermally insulating mat is arranged between the rupture membrane and the at least one electrode stack. This allows the material properties of the insulating mat to be used as a particle filter, so that only gaseous components can be released from the cell housing.

[0035] According to a further embodiment, at least one thermally effective element is arranged between at least one wall of the cell housing and between at least one electrode stack. Preferably, the thermally effective element is configured to absorb a quantity of heat upon exposure to heat through the enthalpy of fusion and / or vaporization and / or to form an insulating gap between the electrode stack and the cell housing. This allows the thermally effective element itself to act reflectively and / or insulatingly, thereby protecting certain areas of the cell housing wall or the entire cell housing from thermal overload and subsequent melting.Protection against thermal overload can also be understood as delaying and / or limiting melting of the cell casing to certain areas, or preventing melting even in the event of thermal runaway of the battery cell.

[0036] The thermally active element can also act in such a way that a filled or unfilled gap is formed by melting, sublimation, or evaporation during thermal runaway of the battery cell. A material of the thermally active element that has assumed a gaseous and / or liquid state under the influence of heat can act as an insulating medium.

[0037] Alternatively or additionally, the liquid or gaseous material of the thermally active element can escape from the internal volume of the cell casing, leaving an air gap that acts as insulation between the thermally active electrode stack and a wall of the cell casing. Alternatively or additionally, the thermally active element can be configured to at least partially absorb the heat generated during thermal runaway of the battery cell through ablation cooling, thus providing a cooling effect to the wall of the cell casing. For this purpose, the thermally active element can comprise a pyrolytic or sublimating material, such as synthetic resins.

[0038] In a further embodiment, the thermally active element can function as a capacitive cooling element, thus absorbing some of the generated heat, for example, from a thermally continuous electrode stack. A similar effect can be achieved by the cell casing, which is thickened in certain areas or incorporates an internal and / or external reinforcement element capable of absorbing heat. Capacitive cooling can also be implemented using a phase-change material, also known as a PCM, which can absorb a particularly large amount of heat within a specific temperature range through a phase transition.

[0039] Depending on the design, thermal protection of the cell housing can be achieved through conductive cooling. This involves at least a partial thermal connection of the cell housing to a coolant. The thermal connection can be direct, so that the cell housing is directly exposed to the coolant flowing from the outside. Alternatively or additionally, the thermal connection can be indirect, using cooling plates or cooling channels that dissipate heat from the cell housing walls.

[0040] The aforementioned measures for thermal stabilization and thermal protection of the cell casing can be used individually or separately, as well as in any combination. This allows for thermal reinforcement, thermal shielding, and / or cooling of the cell casing. Furthermore, these measures can also perform additional functions, such as providing extra mechanical reinforcement or preventing particle leakage, thus integrating functionality. A ceramic fiber mat, for example made of Al₂O₃, can act as a filter in front of the rupture membrane, allowing only pure gas to pass through in the event of thermal runaway. Moreover, these measures for thermal stabilization and thermal protection of the cell casing are not limited to a specific type of battery cell or cell casing design.For example, the cell casing can have a prismatic shape, a round shape, and the like.

[0041] Several embodiments of the invention are explained in more detail below with reference to the drawings. The drawings show:

[0042] Fig. 1 shows a perspective view of an arrangement according to a first embodiment of the invention,

[0043] Fig. 2 is an exploded view to illustrate the structure of a battery cell with an arrangement from Fig. 1 according to an embodiment of the invention.

[0044] Fig. 3 shows a sectional view of a bottom-side area of ​​the battery cell from Fig. 2.

[0045] Fig. 4 shows a sectional view of a bottom-side area of ​​a battery cell according to the invention with a thermal reinforcement in the form of a thickening,

[0046] Fig. 5 shows a sectional view of a bottom-side area of ​​a battery cell according to the invention with thermal reinforcement in the form of a plating,

[0047] Figs. 6-8 illustrate an arrangement for thermal reinforcement with a region-wise thickening of a cell casing wall; Figs. 9-11 illustrate an arrangement for thermal reinforcement of a cell casing in the form of a reinforcement insert.

[0048] Figs. 12-15 Illustrations of an arrangement for the thermal reinforcement of a cell casing using a reinforcement strip,

[0049] Figs. 16-17 Illustrations of an arrangement for the thermal reinforcement of a cell casing by a partial coating,

[0050] Figs. 18-19 Illustrations of an arrangement for thermal reinforcement of a cell casing by partial plating of the cell casing,

[0051] Figs. 20-21 Illustrations of an arrangement for thermally reinforcing a cell housing by insulating the cell housing from an electrode stack with a thermally insulating mat,

[0052] Figs. 22-23 Illustrations of an arrangement for the thermal reinforcement of a cell housing in the form of a reinforcement insert according to a further embodiment,

[0053] In the illustrations, identical reference numerals denote the same elements or structural components. The sizes and relative positions of the elements in the illustrations are not necessarily drawn to scale, and some of these elements are shown enlarged and repositioned for clarity. Furthermore, the specific shapes of the drawn elements are not intended to convey information about the actual shape of the individual elements but were chosen solely for easier identification in the illustrations. Fig. 1 shows a perspective view of a reinforcement arrangement or arrangement 10 according to a first embodiment of the invention. The arrangement 10 serves for the thermal reinforcement of a cell housing 20 of a battery cell 100, which is illustrated by way of example in Fig. 2. Fig. 2 shows an exploded view to illustrate an assembly of the battery cell 100 with the arrangement 10 from Fig. 1.

[0054] The arrangement 10 comprises a cell housing 20 with an internal volume V and at least one electrode stack 30. Depending on the configuration, the at least one electrode stack 30 can also be designed as an electrode winding and comprise several unnumbered anode foils, cathode foils, and separator foils.

[0055] The electrode stack 30 is arranged in the inner volume V of the cell housing 20 and can also comprise a solid or liquid electrolyte. In the illustrated embodiment, the cell housing 20 is thermally reinforced by an internally arranged reinforcing element 11 made of a metal, such as aluminum.

[0056] In Fig. 1, a rupture membrane 40 is inserted into the reinforcement element 11 and connected to the reinforcement element 11 by laser welding. Subsequently, the reinforcement element 11 with the rupture membrane 40 is pushed into the cell housing 20 from the inside and bonded to the cell housing 20.

[0057] The burst membrane 40 is positioned in a bottom-side area of ​​the battery cell 100 or the cell housing 20 and is intended to point towards a substrate or in the direction of gravity in an installation position of the battery cell 100.

[0058] The cell housing 20 can be formed, for example, by a cell housing shell 21 and at least one cell lid 22. Depending on the design, the cell housing shell 21 can have two openings 23, which can be closed by two cell lids 22, 24 in order to seal the internal volume V of the cell housing 20.

[0059] In the illustrated embodiments, the cell casing 21 consists of four walls 25, 26, which enable the formation of a prismatic shape. Depending on the design, the cell casing 21 can also consist of one wall 25 or of more than four walls, for example to form a cylindrical cell or a differently shaped battery cell 100.

[0060] In a bottom wall 26 of the cell casing shell 21 of the cell casing 20 an opening or burst opening 27 is provided, which allows gases and particles to be discharged in the event of overpressure in the internal volume V.

[0061] This burst opening 27 is preferably covered or closed by the burst membrane 40. In Fig. 1 and Fig. 2, the arrangement 10 is rotated such that the bottom wall 26 points upwards, contrary to its usual installation position, in order to illustrate the structure of the arrangement 10.

[0062] In the embodiment shown in Fig. 1 to Fig. 3, the bursting membrane 40 is inserted into an opening or recess 12 of the reinforcing element 11.

[0063] The reinforcing element 11 with the rupture membrane 40 is placed against the inner side of the bottom wall 26 of the cell housing 20. The rupture membrane 40 can then be indirectly bonded to the bottom wall 26 either by means of the reinforcing element 11 or by means of an externally applied weld seam S. This connection is illustrated in a sectional view in Fig. 3.

[0064] The reinforcing element 11, designed as a reinforcing strip and to which the venting membrane or bursting membrane 40 is attached on the inside, is connected to the cell housing 20 from the outside by means of a through-weld or fillet weld. Sufficient material thickness of the reinforcing element 11 along a vertical direction H on the bottom wall 26 or the underside of the housing shell of the cell housing 20 prevents or delays destruction of the cell housing 20 by hot venting gas in the event of thermal runaway.

[0065] Furthermore, the cell casing shell 21 can also be mechanically reinforced by the welded reinforcement element 11 in the area of ​​the burst opening 27 in order to compensate for tensile forces on the thin and sensitive burst membrane 40 that arise in the case of increasing cell internal pressure in the internal volume V.

[0066] After forming such a reinforcement arrangement 10, cell components, such as the electrode stack 30, can be inserted into the cell casing 21, and the cell casing 21 can be closed by cell covers 22, 23. A possible difference between the arrangement 10 and the battery cell 100 may be, for example, that the battery cell 100 has additional components, such as insulation, current collectors or cell connectors, contact elements in or on the cell covers 22, 24, and the like.

[0067] In the illustrated embodiments, the rupture membrane 40 is designed as a separate component and is materially bonded into the battery cell 100 or the cell housing 20 by an additional joining step. Depending on the design, the rupture membrane 40 can be directly pressed into the cell housing shell 21.

[0068] Fig. 4 shows a further sectional view of a bottom-side area of ​​a battery cell 100 according to the invention with a thermal reinforcement in the form of a region-wise thickening of the bottom-side wall 26 of the cell housing shell 21 .

[0069] The bottom region of the battery cell 100 forms a section on which the battery cell 100 can be placed on a surface (not shown). Gravity acts towards the bottom wall 26, which serves as the base or lowest point of the battery cell 100. The battery cell 100 can be positioned on a base or a receptacle of a battery module, a mounting frame, a support structure, a battery system, or the like. The rupture membrane 40 can advantageously point in the direction of gravity or downwards and, in the event of thermal runaway, discharge the resulting gases, particles, and liquids from the internal volume V at the bottom.

[0070] In the embodiment shown in Fig. 4, the cell structure can be adapted by appropriately designing an extrusion die such that the underside of the cell casing shell 21, or the bottom wall 26, is reinforced particularly cost-effectively by a defined thickening 14 without additional components. This results in the bottom wall 26 having a greater material thickness than the other walls 25.

[0071] The cell casing shell 21 can be manufactured in one piece by an extrusion process, in which the bottom wall 26 can be adjusted to have a greater material thickness compared to the rest of the cell casing shell 21 or thickening 14.

[0072] Figure 5 shows a cross-sectional view of a bottom-side region of a battery cell 100 according to the invention, featuring thermal reinforcement in the form of a plating 13. In contrast to the embodiments already described, material reinforcement by means of a plating is implemented on the bottom wall 26 of the cell housing 20. In the area of ​​the opening 27, which is positioned in the bottom wall 26, a plating made of temperature-resistant stainless steel or another temperature-resistant metal or metal alloy is applied externally. The applied plating 13 surrounds the rupture opening 27 circumferentially and can, for example, cover the entire or almost the entire bottom wall 26, either locally in the area of ​​the rupture opening 27 or completely. A temperature-resistant metal or metal alloy preferably has a higher melting point than the material of the cell housing 20.

[0073] In this embodiment, the cell casing 21 can be welded from a box-shaped sheet metal blank. The blank can already have a plating 13 on the outside in the area of ​​the rupture opening 27 or so-called vent opening, which is bonded to the material of the blank or cell casing 20 by a rolling process with or without subsequent annealing. The material of the blank or cell casing 20 can, for example, be an aluminum alloy.

[0074] Before bending the clad sheet, the bursting membrane 40 can be positioned and welded inside, or in the direction of the internal volume V to be formed, so that the contact point between the stainless steel cladding 13 and the aluminum base material cannot be wetted by an electrolyte in the internal volume V. This effectively prevents contact corrosion.

[0075] Figures 6, 7 and 8 show illustrations of an arrangement 10 for thermal reinforcement of the cell housing 20, in particular the bottom cell wall 26 of the cell housing shell 21 of the cell housing 20, with a region-wise thickening 14 of the bottom wall 26 of the cell housing 20.

[0076] In the illustrated embodiment, the entire bottom wall 26 can be thickened. Alternatively, the rupture opening 27 in the bottom wall 26 can be framed by the thickening 14 to achieve local thermal reinforcement. By way of example, the bottom wall 26 is designed as a thickening 14. In contrast to the embodiment shown in Fig. 4, here the thickening 14 is formed by rolling the sheet metal shown in Fig. 6 and not by a deep-drawing process. The sheet metal can be designed as a profiled sheet. The sheet metal shown in Fig. 6 can be formed into a cell housing shell 21 by bending and welding, which is illustrated in Fig. 7. For technically simple bending of the sheet metal, an edge region of the bottom wall 26 can be designed with a reduced material thickness. This variation in the material thickness of the bottom wall 26 is shown in Fig.Figure 8 illustrates this in a detailed view of the bottom area of ​​battery cell 100.

[0077] Figures 9, 10 and 11 show illustrations of an arrangement 10 for thermal reinforcement of a cell housing 20 in the form of a reinforcement insert 11.

[0078] In contrast to the embodiment shown in Fig. 1, the reinforcing element 11 is not welded directly to the cell housing 20, but is indirectly locked or fixed in place by the bursting membrane 40.

[0079] Analogous to the previously described execution options, a sheet metal with a burst opening 27 is used, which is subsequently bent and welded to form the box-shaped cell housing shell 21.

[0080] Before the sheet metal is bent, a reinforcing element 11 in the form of an insert made of temperature-stable material is placed in a recess 15 provided in the area of ​​the burst opening 27. Such a reinforcing element 11 can, for example, be made of stainless steel, nickel, ceramic, graphite, and the like, and in the illustrated embodiment is not directly welded to the cell housing shell 21.

[0081] The reinforcing element 11 is ring-shaped or frame-shaped and surrounds the rupture opening 27 in the recess 15. Fig. 9 shows an exploded view of the reinforcing element 11, the sheet metal forming the cell housing shell 21, and the rupture membrane 40. In Fig. 10, the rupture membrane 40 is welded to the cell housing shell 21, in particular to the bottom wall 26, and thus acts as a cover for the reinforcing element 11 inserted in the recess 15. Fig. 10 also illustrates the creation of a weld seam S, for example by laser welding.

[0082] By covering the reinforcing element 11 with the rupture membrane 40, the reinforcing element 11 is encapsulated, thus preventing contact between the reinforcing element 11 and the electrolyte. This allows the use of materials for the reinforcing element 11 that are, for example, not chemically resistant to the electrolyte. Figure 11 illustrates a detailed view of the encapsulated arrangement of the reinforcing element 11 in the recess 15.

[0083] The reinforcing element 11 is stepped and protrudes through the rupture opening 27 to thermally reinforce the edge or wall of the rupture opening 27. Furthermore, the stepped shape of the reinforcing element 11 allows for particularly easy assembly through a targeted positive fit between the reinforcing element 11 and the bottom wall 26.

[0084] Figures 12, 13, 14, and 15 illustrate an arrangement 10 for the thermal reinforcement of a cell housing 20 using a reinforcement element 11 in the form of a reinforcement strip. In contrast to the previously described variants of the reinforcement element 11, this illustration depicts a reinforcement element 11 in the form of a reinforcement strip, which can be fixedly positioned within the cell housing 20 without a material bond.

[0085] The reinforcing element 11, designed as a reinforcing strip, can be inserted into recesses 15 or grooves provided at the edges and thus locked in place at least along one spatial direction H. Fig. 13 illustrates, by way of example, the insertion of the reinforcing element 11 in the direction of the arrow, i.e., in the longitudinal direction L, into the recesses 15 through one of the two openings 23 of the cell housing shell 21. The recesses 15 are arranged on two opposing walls 25 of the cell housing shell 21. The reinforcing element 11, positioned in the recesses 15, can be locked against displacement in the longitudinal direction L by cell covers 24 attached to the ends of the cell housing shell 21. Such locking of the reinforcing element 11 in the longitudinal direction L is illustrated in Fig. 15.

[0086] Since the reinforcing element 11 is in contact with the aluminum cell casing 21 and the electrolyte, it can be made of aluminum or coated with aluminum on all sides to prevent contact corrosion. Such an aluminum coating can be applied, for example, by flame spraying or dipping. Alternatively, the reinforcing element 11 can be coated with an electrically non-conductive material, such as PP or PET, a ceramic, or the like. These measures to prevent contact corrosion can be used, for example, if the reinforcing element 11 is made of stainless steel or nickel. Depending on the design, the reinforcing element 11 can be made entirely of a non-conductive and temperature-stable material, such as a ceramic.The ceramic materials used for the reinforcing element 11 can be Al2O3, Si3N4, ZrCh and the like.

[0087] Figures 16 and 17 show further illustrations of an arrangement 10 for the thermal reinforcement of a cell housing 20 by a partial coating 16. Analogous to the embodiment shown in Figures 9 and 10, the box-shaped cell housing shell 21 can be manufactured from a bent and welded sheet metal. The coating 16 is designed as a material that is applied at least partially by a metallurgical bond.

[0088] In the illustrated embodiment, before bending the sheet metal and before welding the burst membrane 40 over the burst opening 27, the area around the venting opening or burst opening 27 on the future cell interior of the bottom wall 26 is provided with a temperature- and electrolyte-stable coating 16.

[0089] The coating 16 can consist of a ceramic, such as Al₂O₃, which can be applied by a thermal spraying process. Due to the lack of electrical conductivity of the exemplary ceramic coating 16, contact corrosion can be avoided.

[0090] Figures 18 and 19 show illustrations of an arrangement 10 for the thermal reinforcement of a cell housing 20 by partial plating 13 of the cell housing 20. In contrast to the embodiment shown in Figure 5, the bottom wall 26 is provided independently of the remaining walls 25 of the cell housing shell 21. The bottom wall 26 is provided with a plating 13 on one side. In the illustrated embodiment, the plating 13 is applied to the outside of the bottom wall 26 of the cell housing 20.

[0091] The bottom wall 26 forms the underside of the battery cell 100 and is, for example, made of aluminum. For thermal reinforcement, the bottom wall 26 is clad and / or coated with stainless steel or nickel. A rupture opening 27 is incorporated into the already clad and / or coated bottom wall 26 to accommodate the rupture membrane 40.

[0092] The bursting membrane 40 is welded, for example, to the inside of the bottom wall 26, so that a bursting membrane 40 made of aluminium can be welded particularly reliably to an identical material of the bottom wall 26.

[0093] The remaining part 25 of the cell casing shell 21 can also be made of aluminum and is bent into a U-shape. The thermally reinforced bottom wall 26 with the rupture membrane 40 can then be attached to the remaining walls 25 of the cell casing shell 21 with two simple and technically straightforward welds S to complete the box-shaped cell casing shell 21.

[0094] Figure 19 shows a detailed view of the bottom area or underside of the battery cell 100, clearly illustrating the welded joints S between the walls 25, 26 of the cell casing 21. Since the contact point between the plating 13 and the material of the bottom wall 26 does not come into contact with the electrolyte, contact corrosion is avoided.

[0095] Thermal reinforcement using a plating 13 can be achieved, for example, by bonding two sheets of different materials, such as stainless steel and aluminum, together. The sheets, joined by rolling, can also be heated. Alternatively or additionally to plating 13, areas of the cell housing 20 can be provided with a coating 16. For a coating 16, the material of the coating 16 can preferably be converted into a gaseous, plasma, or liquid state. After the change of state, the coating 16 can be applied.

[0096] Figures 20 and 21 show illustrations of an arrangement 10 for thermally reinforcing a cell housing 20 by insulating the cell housing 20 from an electrode stack 30 by a thermally effective element 31. In the illustrated embodiment, the thermally effective element 31 is implemented as a thermally insulating mat 31.

[0097] The thermally insulating mat 31 is arranged in the inner volume V of the cell housing 20 and surrounds at least part of the at least one electrode stack 30. In particular, the mat 31 can encase the electrode stack 30 to form thermal insulation between the walls 25, 26 of the cell housing 20 and the electrode stack 30. The thermally insulating mat 31 is, by way of example, designed as a ceramic fiber mat and can consist of Al₂O₃, SisN₄, and the like.

[0098] The high-temperature resistant mat 31 can also have a filtering effect to retain solid and flammable particles in the internal volume V of the cell housing 20 in the event of thermal runaway. This effect can also reduce the specific heat capacity of the gas passing through during thermal runaway. This measure can thus lower the temperature of the escaping gas and prevent the cell housing 20 from melting in the area of ​​the rupture membrane 40 or the corresponding rupture opening 27.

[0099] Furthermore, an additional insulating effect is achieved through the low specific thermal conductivity of the mat 31 and the gap created by it between the electrode stack 30 and the cell housing 20.

[0100] Figures 22 and 23 illustrate an arrangement 10 for the thermal reinforcement of a cell housing 30 in the form of a reinforcement insert 11 according to a further embodiment. In contrast to the reinforcement insert 11 shown in Figures 9 to 11, here the reinforcement insert 11 is inserted into a cell cover 24 of the cell housing 20. The battery cell 100 shown in Figures 22 and 23 has, in the illustrated embodiment, exactly one opening 23 for inserting the electrode stack 30. The internal volume V of the cell housing 20 is thus closed by a cell cover 24.

[0101] The illustrated battery cell 100 is designed as a classic, prismatic hard-case cell, in which both battery terminals and the rupture vent 27 for venting in the event of thermal runaway are located in the cell cover 24 on the top of the cell. Fig. 22 shows an exploded view illustrating that, analogous to the embodiment shown in Fig. 11, the rupture membrane 40 conceals and locks a reinforcing element 11 in the form of a reinforcing insert in a recess 15. Fig. 22 shows the cell cover 24 from a bottom side (i.e., a side facing the internal volume V) and from a top side (i.e., an external side) of the battery cell 100.

[0102] The thermal reinforcement of the sensitive rupture opening 27 for the rupture membrane 40 is achieved by the reinforcement element 11, made of a temperature-stable material such as stainless steel, nickel, ceramic, or the like, which surrounds the rupture opening 27 circumferentially within the recess 15. The reinforcement element 11 is inserted into the recess 15 from the inside of the cell housing cover 24 and then covered by the rupture membrane 40, allowing the rupture membrane 40 to separate the electrolyte from the reinforcement element 11. The rupture membrane 40 can then be welded to the cell cover 24. Figure 23 illustrates the structure of the battery cell 100 in the embodiment shown in Figure 22 by means of a sectional view in the area of ​​the cell cover 24.The cell cover 24 forms a top side of the battery cell 100 arranged opposite to the bottom side area, which can point against a direction of gravity when the battery cell 100 is installed.

[0103] The arrangement of the bottom surface or bottom wall 26 and the top surface can vary depending on the design and arrangement of the battery cell 100. In particular, a battery cell 100 can also be mounted laterally or horizontally, so that, for example, the bottom wall 26 is oriented perpendicular to the direction of gravity. The battery cell 100 can also be installed at an angle and thus, in its installed state, have a bottom wall 26 oriented perpendicular to or opposite to the direction of gravity. The orientation of the bottom wall 26 can correspond to a surface normal or run parallel to the surface normal.The different embodiments described in the figures can be used in isolation or in any combination to effect at least partial thermal reinforcement and / or at least partial thermal insulation of the cell housing 20 from the electrode stack 30.

[0104] The thermal insulation and / or thermal reinforcement of the cell housing 20 and / or the thermal insulation 30 of the cell housing 20 relative to the electrode stack 30 can be designed as a permanent reinforcement or insulation or as a temporary reinforcement or insulation, in which the corresponding insulating and / or reinforcing effect can be activated in the event of thermal runaway or can be progressively reduced by the action of heat.

[0105] Without the measures described, in the event of thermal runaway in a high-energy cell chemistry starting at the edge of the burst opening 27, the aluminium casing can melt and subsequently expose the internal volume V of the cell casing 20.

Claims

REQUIREMENTS 1. Arrangement (10) for thermal reinforcement of a cell housing (20) of a battery cell (100), comprising a cell housing (20) with an internal volume (V) and comprising at least one electrode stack (30) which is arranged in the internal volume (V) of the cell housing (20), wherein the cell housing (20) is at least partially thermally reinforced and / or at least partially insulated from the electrode stack (30).

2. Arrangement according to claim 1, wherein the cell casing is thermally reinforced by a material (13, 14) applied at least partially in a material-bonded manner, wherein the material (13, 14) is arranged on the inside and / or outside.

3. Arrangement according to claim 1 or 2, wherein the cell casing (20) is thermally reinforced by at least a partial thickening (14) of at least one wall (25, 26).

4. Arrangement according to one of claims 1 to 3, wherein the cell housing (20) is thermally reinforced by a coating (16) applied at least in certain areas, wherein the coating (16) is applied on the inside and / or outside of at least one wall (25, 26) of the cell housing (20).

5. Arrangement according to one of claims 1 to 4, wherein the cell housing (20) is thermally reinforced by at least one reinforcement element (11) arranged on the inside and / or outside.

6. Arrangement according to claim 5, wherein the reinforcing element (11) is designed in the form of a reinforcing insert which is arranged in a bursting opening (27) or limits a bursting opening (27) at its edge.

7. Arrangement according to claim 5 or 6, wherein the reinforcing element (11) is fixed to the cell housing (20) by a burst membrane (40).

8. Arrangement according to one of claims 1 to 7, wherein the at least one electrode stack (30) arranged in the inner volume (V) of the cell housing (20) is enclosed at least partially by a thermally effective element (31), wherein the thermally effective element (31) is designed as a thermally insulating mat and / or as a thermally insulating plate, wherein the cell housing (20) is insulated at least partially by the thermally insulating mat and / or thermally insulating plate from the electrode stack (30).

9. Arrangement according to claim 8, wherein the thermally insulating mat is designed as a ceramic fiber mat.

10. Arrangement according to claim 8 or 9, wherein the cell housing (20) has at least one burst membrane (40), wherein the thermally insulating mat is arranged between the burst membrane and the at least one electrode stack.

11. Arrangement according to one of claims 1 to 10, wherein at least one thermally effective element (31) is arranged between at least one wall (25, 26) of the cell housing (20) and between at least one electrode stack (30), wherein the thermally effective element (31) is configured to absorb a quantity of heat by melting and / or evaporation when exposed to heat and / or to form an insulating gap between the electrode stack (30) and the cell housing (20).

12. Battery cell (100) comprising an arrangement (10) according to one of the preceding claims.

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