Cell housing arrangement having cell housing and thermal protection element for stabilizing cell housing, battery cell and motor vehicle

Abstract

The invention relates to a cell housing arrangement (12) having a cell housing (14) for a prismatic battery cell (10), the cell housing (14) having: a first cell wall (16) in which releasable cell vent openings (18) are arranged; a second cell wall (19) and a third cell wall (20), which lie opposite each other and adjoin the first cell wall (19) by a first edge (22) and a second edge (24) of the cell housing (14), the cell housing arrangement (12) having at least one thermal protection element (36; 38, 40) which is arranged at least on the outer side of at least one part of the second cell wall (19). In this case, the thermal protection element (36; 38, 40) is designed as a metal foil (38) or a fireproof paper (40).

Description

Technical Field

[0001] This invention relates to a single-cell housing assembly having a single-cell housing for a prismatic battery cell, wherein the single-cell housing has a first single-cell wall, a second single-cell wall, and a third single-cell wall, wherein a release opening for single-cell venting is arranged in the first single-cell wall, the second single-cell wall and the third single-cell wall are opposite to each other and abut against the first single-cell wall through a first edge and a second edge of the single-cell housing, respectively, wherein the single-cell housing assembly has at least one thermal protection element disposed on the outer side of at least a portion of the second single-cell wall. Furthermore, this invention also relates to a battery cell and a motor vehicle. Background Technology

[0002] Battery cells, or their casings, typically have venting openings, such as burstable membranes, that allow controlled venting in the event of thermal runaway, preventing explosion. However, in cases of poor cell integrity, the casing may crack at unintended locations during thermal runaway. This leads to unintended gas flows along unpredictable paths. Furthermore, within a cell cluster, the potential for ignition in adjacent cells increases due to the escape of hot gases from unintended locations.

[0003] DE 10 2021 000 029 A1 describes a multilayer protective element for a battery, having a heat-resistant carrier layer and a fiber layer, wherein the protective element is breathable. It is specified that each individual cell of the battery is individually encapsulated by this protective element.

[0004] Using multi-layered protective elements in batteries typically requires a significant amount of installation space. Furthermore, permeable implementations of such protective elements often weaken their protective function, as hot gases can more easily penetrate them, for example.

[0005] EP 4 199 222 A1 describes a battery cell having a cell housing, a safety valve, and a fabric strip that surrounds the housing and covers the safety valve, allowing gas to pass through the fabric strip.

[0006] DE 10 2021 130 417 A1 describes an energy storage cell having a cylindrical encapsulation that forms the cell housing and is partially made of steel and / or aluminum, thus enabling electrical conductivity. To achieve electrical isolation of the cell, an additional coating is provided on the encapsulation, the coating being electrically insulating and capable of being implemented as a KTL coating and / or anodized coating. Summary of the Invention

[0007] The purpose of this invention is to provide a single-cell housing device, a battery cell, and a motor vehicle that can minimize the possibility of gas escaping from undesirable locations within the single-cell housing in the event of thermal runaway of the battery cell.

[0008] This objective is achieved by a single-cell housing assembly, a battery cell, and a motor vehicle having the features according to the respective independent claims. Advantageous embodiments of the invention are the subject of the dependent patent claims, the specification, and the drawings.

[0009] The cell housing device according to the invention includes a cell housing for a prismatic battery cell, wherein the cell housing has: a first cell wall in which a release cell vent is arranged; a second cell wall and a third cell wall, which are opposite to each other and abut against the first cell wall via a first edge and a second edge of the cell housing, respectively; and wherein the cell housing device has at least one thermal protection element, which is arranged on the outer side of at least a portion of the second cell wall. Here, the thermal protection element is designed as a metal foil or fire-retardant paper.

[0010] Metal foil and fire-retardant paper typically possess very high heat resistance and mechanical durability, which allows thermal protection elements to be implemented particularly thinly, especially as a single layer. This saves installation space, cost, and weight, but most importantly, it allows the thermal protection element to be applied to the cell housing with tolerance compensation and in a form-fitting or close-fitting manner. This significantly enhances the stabilizing effect of the thermal protection element on the cell housing. It is particularly advantageous to arrange such thermal protection elements in the form of metal foil or fire-retardant paper on the sidewalls of the cell housing, especially on the sidewalls with the largest area of ​​prismatic cell housings, such as the second or third cell wall, because this provides lateral support and / or mechanical stability to the cell housing and facilitates restricted venting of the cell through the cell venting opening in the first cell wall. This effectively prevents the cell from venting to adjacent cells via undesirable paths, such as through the sidewalls.

[0011] Prismatic battery cells are generally designed to be square. The cell casing of such cells is also square. Here, the cell casing typically encloses the interior of the cell, i.e., it has an internal space in which the cell's chemical components can be arranged, thereby providing the battery cell. Therefore, this prismatic cell casing has six cell walls arranged in pairs facing each other. The first and second cell walls are preferably the cell walls with the largest area in the cell casing. In a cell stack having multiple battery cells arranged side-by-side along the stacking direction, the battery cells are preferably arranged opposite each other such that the cell walls with the largest area face each other. Therefore, by arranging thermal protection elements at least on a portion of this largest cell wall (here, the second cell wall), protection can be provided, particularly for adjacent cells in the cell stack.

[0012] A releasable cell vent should be understood as an opening that is closed but capable of being released, i.e., opened, under specific conditions. Therefore, such a releasable cell vent can have both closed and open states, and can transition from the closed state to the open state. The transition need not be reversible. A transition from the open state to the closed state may no longer be possible, for example, in the case where the releasable cell vent is designed as a bursting membrane. The releasable cell vent can be designed as a passively released cell vent depending on pressure, for example, designed as a pressure relief valve and / or a bursting membrane and / or a predetermined fracture point in the cell housing, etc. Therefore, the releasable cell vent is closed under normal conditions, thus fluidly isolating the interior of the cell from the environment. From a determined overpressure, the cell vent opens, thus establishing a fluid connection between the interior of the cell and its environment to allow gas to escape from the cell.

[0013] The cell casing can be made of aluminum, for example. Other materials are also feasible. Aluminum has the advantage of providing a particularly lightweight and advantageous cell casing. Combined with thermal protection elements, sufficient stability can be ensured even in the event of thermal runaway of the battery cell. Here, the thermal protection elements can, but do not necessarily, cover the entire second cell wall. The thermal protection elements can also be located only in a portion of the second cell wall.

[0014] Here, metal foil should be understood as a thin, flat element made of metallic material. Fire-retardant paper can also be understood as such a thin, flat element. Fire-retardant paper can be supplied as a fibrous product, and is particularly made of non-metallic and / or electrically insulating materials. This fire-retardant paper can be supplied, particularly as a non-woven and / or non-textile flat element. Fire-retardant paper typically possesses very high temperature resistance and flame retardancy. Both metal foil and fire-retardant paper can be flexible and / or bendable and / or foldable. Thus, they can be form-fitted tightly onto the monocoque in the form of a thermal protection element. A thermal protection element can also be referred to as a protective film.

[0015] In an advantageous embodiment of the invention, a thermal protection element is disposed on at least a portion of the first cell wall and is arranged to at least partially or completely cover at least the first edge in the longitudinal direction of the edge. The longitudinal direction of the edge can be defined, for example, as a first direction. When the cell housing is disposed as part of a cell stack, this direction is preferably perpendicular to such stacking direction. Therefore, the thermal protection element can be implemented as bent or folded. Thus, the thermal protection element includes at least a first element region abutting against the second cell wall and a second element region abutting against the first cell wall, such that at least the first edge is covered by the thermal protection element. This is based on the understanding that in the event of thermal runaway of the cell and in the event of venting of such the cell, cracking of the cell housing occurs, particularly in the region of the edge adjacent to the cell wall where a cell venting opening for release is disposed. Since the thermal protection element at least covers the first edge, damage to the cell housing or undesirable cracking of the cell housing, particularly in the edge region, can be advantageously prevented. Here, in the longitudinal direction of the edge, the thermal protection element may completely cover the first edge or only partially cover the first edge. Based on this first direction, the release vent opening of the unit can be arranged, for example, centrally or in the central region of the first unit wall. In this case, it is advantageous that the thermal protection element also covers at least the central region of the edge, or more precisely, the region located in the middle region, in the first direction corresponding to the longitudinal direction of the edge. If the thermal protection element completely covers the first edge in the longitudinal direction of the edge, particularly effective protection can be provided.

[0016] According to another advantageous design of the invention, the thermal protection element is also arranged at at least a portion of the third unit wall and is arranged to at least partially or completely cover the second edge in the longitudinal direction of the edge. Accordingly, this also provides protection for the third unit wall, especially for the second edge. Here, the thermal protection element is preferably implemented as a single piece. Therefore, it is not necessary to provide multiple separate thermal protection elements to cover the two edges. The thermal protection element can, for example, be designed as U-shaped, or folded, in cross-section perpendicular to the longitudinal direction of the edge. The thermal protection element can, for example, have a third element region in addition to the two first element regions and second element regions described above, which is located on the outer side of the third unit wall. The individual element regions can be adjacent to each other and, for example, implemented as substantially rectangular.

[0017] Here, the thermal protection element may completely or only partially cover the second edge, for example, only covering the second edge in the middle region based on the longitudinal direction of the edge.

[0018] According to another advantageous design of the invention, the thermal protection element extends, in particular, planarly from a first edge to a second edge on the first cell wall and has a notch in the region of the cell venting opening. The notch can be implemented as a through-hole or a cavity, etc. The geometry of the notch can correspond to the geometry of the cell venting opening. Preferably, the notch is configured such that the cell venting opening is not covered by the thermal protection element. The edge of such a notch can, for example, be directly adjacent to the boundary of the area of ​​such cell venting opening. Thus, gas escapes unimpeded from the battery cell, particularly from the cell venting opening, without requiring the thermal protection element itself to be permeable. Therefore, the metal foil or fire-retardant paper can be substantially impermeable.

[0019] According to another advantageous design of the invention, the thermal protection element is flexible and, in particular, has a material thickness of a maximum of 1 mm. In other words, the flexibility of the thermal protection element can be achieved through a particularly thin material thickness, for example, a maximum of 1 mm or even less. This allows the thermal protection element to be fitted tightly and shape-fitted to the surface of the monocoque housing in a particularly simple manner. Therefore, gaps can be prevented particularly effectively. This, in turn, contributes to the stabilizing effect of the thermal protection element.

[0020] Material thickness can also be referred to as the thickness of the thermal protection element or wall thickness, etc. It indicates the dimension of the thermal protection element perpendicular to its planar extension.

[0021] According to another advantageous design of the invention, the thermal protection element is designed as a steel foil, with a material thickness of a maximum of 0.2 mm. Steel has particularly high temperature resistance and a particularly high melting point, thereby providing particularly good protection and particularly high stability. Even with the steel foil material thickness designed to be a maximum of 0.2 mm, it can still be form-fitted and seamlessly attached to the monocoque housing, requiring almost no additional installation space, and can also be manufactured at a particularly light weight and low cost.

[0022] According to another advantageous design of the invention, the thermal protection element is designed as fire-retardant paper and has a material thickness of a maximum of 0.5 mm. Similarly, when the thermal protection element is designed as fire-retardant paper, its walls can be designed to be particularly thin while still providing reliable protection.

[0023] Furthermore, for manufacturing the monocoque assembly, the thermal protection element can be first manufactured as a flat, flat element from a flat semi-finished product in this thin design, and then accordingly molded onto the monocoque. This is particularly advantageous, as mentioned above, when implementing the thermal protection element in a bent configuration, especially in a U-shaped design.

[0024] According to another advantageous design of the invention, the thermal protection element is designed to adhere to, for example, be bonded to, the monocoque housing. This allows the thermal protection element to be fixed to the monocoque housing particularly easily. Furthermore, it allows the thermal protection element to be arranged particularly easily and seamlessly within the monocoque housing.

[0025] Furthermore, the present invention also relates to a battery cell having a cell housing device according to the present invention or one of its design schemes.

[0026] Furthermore, the present invention relates to a battery for motor vehicles, comprising a battery cell according to the invention or one of its design embodiments. The battery may, for example, have multiple such battery cells. The battery cells may be arranged in a cell stack, which may be designed as described above. Furthermore, the cell stack may be clamped along the stacking direction. This improves the stability of the fire-resistant element. The battery may, for example, be implemented as a high-voltage battery.

[0027] Furthermore, the present invention also relates to a motor vehicle having a battery cell according to the invention or one of its designs, and a battery according to the invention or one of its designs. The motor vehicle according to the invention is preferably designed as an automobile, particularly a passenger car or commercial vehicle, or as a passenger bus or motorcycle. The motor vehicle may, for example, be an electric vehicle.

[0028] The present invention also includes a battery cell according to the invention and a battery according to the invention, having the features already described in conjunction with improvements to the cell housing device according to the invention. Therefore, corresponding improvements to the method according to the invention will not be described further here.

[0029] The invention also includes combinations of features of the described embodiments. Therefore, the invention also includes implementations that each have combinations of features of a plurality of embodiments described, provided that these embodiments are not described as mutually exclusive. Attached Figure Description

[0030] The embodiments of the present invention are described below. Wherein:

[0031] Figure 1 A schematic perspective view of a prism-shaped battery cell with a single-cell housing assembly according to an embodiment of the present invention is shown;

[0032] Figure 2 An embodiment according to the present invention is shown. Figure 1 A schematic side view of a single battery cell; and

[0033] Figure 3 An embodiment according to the present invention is shown. Figure 1A schematic cross-sectional view of a single battery cell. Detailed Implementation

[0034] The embodiments described below are preferred embodiments of the present invention. In the embodiments, each of the described components is a separate, independently viewable feature of the present invention, and these features also independently improve the present invention. Therefore, this disclosure also covers other combinations of features in the embodiments that differ from the illustrated combinations of features. Furthermore, the described embodiments can be supplemented by other features among the already described features of the present invention.

[0035] In the accompanying drawings, the same reference numerals respectively denote elements with the same function.

[0036] Figure 1 A schematic perspective view of a battery cell 10 having a cell housing assembly 12 according to an embodiment of the present invention is shown. The cell housing assembly 12 further includes a cell housing 14 that surrounds the interior of the battery cell 10, within which the cell chemical components can be arranged. The cell housing 14 includes a first cell wall 16 in which a release cell vent opening 18, such as a bursting membrane, is arranged. The release cell vent opening 18 may also be referred to as a cell vent, vent hole, or vent opening. Furthermore, the cell housing 14 includes a second cell wall 19 and a third cell wall 20, which are positioned opposite each other in the shown y-direction. Here, the second cell wall 19 is adjacent to the first cell wall 16 by a first edge 22. The third cell wall 20 is adjacent to the first cell wall 16 by a second edge 24. Here, the edges 22 and 24 extend along an edge direction, which corresponds to the shown x-direction. Furthermore, the single-cell housing 14 also includes: a fourth single-cell wall 26, which is positioned opposite to the first single-cell wall 16 in the shown z-direction; and a fifth single-cell wall 28 and a sixth single-cell wall 30, which are positioned opposite to each other in the shown x-direction. In this example, a battery electrode 32 is arranged at the fifth single-cell wall 28, and a battery electrode 34 is arranged at the sixth single-cell wall 30.

[0037] The single-unit housing 14 can be made of, for example, aluminum. Furthermore, the single-unit housing assembly 12 has a heat-protective element 36, shown here in shaded lines. The heat-protective element can be designed as a metal foil, particularly steel foil 38, or as fire-retardant paper 40. In this example, the heat-protective element 36 is arranged to face-fit against the outer sides of the second single-unit wall 19, the first single-unit wall 16, and the third single-unit wall 24. In the region of the release single-unit vent opening 18, the heat-protective element 36 can be configured with a notch 42. Here, in this example, the heat-protective element 36 not only extends along the x-direction to cover the entire first single-unit wall 16, the second single-unit wall 19, and the third single-unit wall 20, but also completely covers the edges 22 and 24 along the x-direction.

[0038] Figure 2 A top view of the fifth unit wall 28 is shown. Figure 1 A schematic side view of the battery cell 10, and Figure 3 It shows Figure 1 A schematic cross-sectional view of the battery cell 10 in the region of the cell vent opening 18, perpendicular to the x-direction shown. As can be seen, the thermal protection element 36 can be implemented in a U-shape. The material thickness D of the thermal protection element 36 is constant, particularly throughout the entire thermal protection element 36, and is especially less than one millimeter. If the thermal protection element 36 is implemented as steel foil 38, the material thickness D is preferably at most 0.2 millimeters, and in the case of fire-retardant paper 40, it is preferably at most 0.5 millimeters. This allows the thermal protection element 36 to be designed to be particularly flexible and easy to fit. This makes it possible to achieve seamless placement at the corresponding sidewalls 19, 16, 20 of the cell housing 14.

[0039] If the battery cell 10 is configured as part of a cell stack having a plurality of battery cells arranged side by side along a stacking direction, then this stacking direction corresponds to the y-direction shown. Therefore, in the event of venting from the battery cell 10, the thermal protection element 36 is particularly able to maintain the stability of the sidewalls 19, 20 facing the adjacent cells and the adjacent edges 22, 24 and effectively prevent undesirable venting in the direction of the adjacent cells.

[0040] The thermal protection element 36 can, for example, be manufactured as a flat element and then shaped according to the geometry of the monocoque 14, and thus designed as a U-shape. Furthermore, the thermal protection element 36 does not necessarily extend to cover the entire monocoque 14 in the x-direction, but can extend only in individual areas of the monocoque 14, particularly in the central region relative to the x-direction. Similarly, the thermal protection element 36 does not necessarily completely cover the sidewalls 19, 20 in the z-direction, but can also be designed so that it does not extend to the fourth monocoque 26 in the direction opposite to the z-direction shown.

[0041] Alternatively, the cell housing 14 may also be surrounded by the thermal protection element 36, such that, for example, even the fourth cell wall 26 is partially or completely covered by the thermal protection element 36. Exemplarily, the cell housing 14 or the battery cell 10 may also be wrapped in fire-retardant paper 40.

[0042] In summary, these examples demonstrate how the stability of the cell, i.e., the cell casing, can be provided by the present invention. This can be achieved, in particular, by applying additional materials to aid cell integrity, such as foil, especially metal foil, or fire-retardant materials, such as fire-retardant paper, especially on the sides of the cell. In the event of cell venting, the cell can open at the cell vent while the rest of the cell casing remains stable. In particular, the edges of the cell casing adjacent to the cell wall with the cell vent can be reliably protected by thermal protection elements. Thermal protection elements can prevent significant cracks in the cell casing in the event of thermal runaway and thermal venting of the cell, which could lead to side melting or breakage of the cell edges at the vent, severely compromising protection of adjacent cells and thus undesirably exacerbating heat transfer. By means of the cell casing device according to the invention and its embodiments, controlled venting behavior of the cell can be achieved by stabilization measures around the vent opening. Stabilization measures can be achieved by applying additional materials, in the form of adhered metal foil or paper, to the cell surface.

Claims

1. A single-cell housing device (12) having a single-cell housing (14) for a prismatic battery cell (10), -in, The single-unit shell (14) has a first single-unit wall (16) in which a release single-unit exhaust opening (18) is arranged. - The monolithic shell has a second monolithic wall (19) and a third monolithic wall (20), the second monolithic wall and the third monolithic wall are opposite to each other and are adjacent to the first monolithic wall (16) through the first edge (22) and the second edge (24) of the monolithic shell (14), respectively. - wherein the single-unit housing assembly (12) has at least one thermal protection element (36; 38, 40), the at least one thermal protection element being arranged on the outer side of at least a portion of the second single-unit wall (19), Its features are, - The heat protection element (36; 38, 40) is designed as a metal foil (38) or fireproof paper (40).

2. The single-shell device (12) according to claim 1, characterized in that, The thermal protection elements (36; 38, 40) are arranged on at least a portion of the first single-unit wall (16) and are arranged to at least partially or completely cover the first edge (22) in the longitudinal direction (x) of the edge.

3. The single-shell device (12) according to any one of the preceding claims, characterized in that, The thermal protection elements (36; 38, 40) are also arranged on at least a portion of the third unit wall (20) and are arranged to at least partially or completely cover the second edge (24) in the longitudinal direction (x) of the edge.

4. The single-shell device (12) according to any one of the preceding claims, characterized in that, The thermal protection element (36; 38, 40) extends from the first edge (22) to the second edge (24) on the first monomer wall (19) and has a notch (42) in the area of ​​the release monomer vent opening (18).

5. The single-shell device (12) according to any one of the preceding claims, characterized in that, The thermal protection elements (36; 38, 40) are flexible and, in particular, have a material thickness (D) of up to one millimeter.

6. The single-shell device (12) according to any one of the preceding claims, characterized in that, The thermal protection elements (36; 38, 40) are designed as steel foil (38), with a material thickness (D) of up to 0.2 mm.

7. The single-shell device (12) according to any one of the preceding claims, characterized in that, The thermal protection elements (36; 38, 40) are designed as fire-retardant paper (40) and have a material thickness (D) of up to 0.5 mm.

8. The single-shell device (12) according to any one of the preceding claims, characterized in that, The thermal protection elements (36; 38, 40) are attached to the single-unit housing (14).

9. A battery cell (10) having a cell housing device (12) according to any one of the preceding claims.

10. A motor vehicle having the battery cell (10) according to claim 9.

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