DOUBLE-WALLED HOUSING AND / OR COOLING SYSTEM FOR PRISMATIC BATTERY CELLS

Abstract

A battery cell comprises a battery cell stack with A anode electrodes, C cathode electrodes, and S separators, where A, C, and S are integers greater than one. A double-walled prismatic housing is designed to contain the battery cell stack, including a can body comprising an inner case, an outer case, and a gap between the inner and outer cases. The battery cell stack is arranged within the inner case. The outer case of the can body defines a first and a second opening at its opposite ends. A first lid portion is attached to the first opening of the outer case. A first bottom portion is attached to the second opening of the outer case.

Description

INTRODUCTION

[0001] The information contained in this section is intended to provide a general context for the disclosure. Work by the presently named inventors, to the extent described in this section, as well as aspects of the description that may not otherwise be considered prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against this disclosure.

[0002] The present disclosure relates to battery cells and, more particularly, to a double-walled housing and / or cooling system for prismatic battery cells.

[0003] Electric vehicles (EVs), such as battery electric vehicles (BEVs), hybrid vehicles, and / or fuel cell vehicles, comprise one or more electric machines and a battery system with one or more battery cells, modules, and / or packs. A power management system is used to control the charging and / or discharging of the battery system during charging and / or driving. SUMMARY

[0004] A battery cell comprises a battery cell stack having A anode electrodes, C cathode electrodes, and S separators, where A, C, and S are integers greater than one. A double-walled prismatic housing is configured to house the battery cell stack, including a can body comprising an inner shell, an outer shell, and a gap between the inner shell and the outer shell. The battery cell stack is disposed within the inner shell. The outer shell of the can body defines first and second openings at opposite ends thereof. A first lid portion is attached to the first opening of the outer shell. A first bottom portion is attached to the second opening of the outer shell.

[0005] In other features, a first side of the outer casing includes a plurality of stiffening sections arranged in a first pattern. A second side of the outer casing includes a plurality of stiffening sections arranged in a second pattern. The first pattern and the second pattern are different. The first pattern and the second pattern are offset to enable nesting of the battery cell with one or more adjacent battery cells. The plurality of stiffening sections includes recesses and / or stiffening beads.

[0006] In other features, the recesses have a rectangular or arcuate cross-section. A thermally conductive material is arranged in the gap between the inner housing and the outer housing. A second cover portion encloses a third opening in the inner housing. A second base portion encloses a fourth opening in the inner housing.

[0007] In other features, at least one of the first lid portion and the first bottom portion includes a vent opening.

[0008] A system comprises a plurality of battery cells and a cooling plate. A thermally conductive material is disposed between the cooling plate and a first of the plurality of battery cells and a second of the plurality of battery cells.

[0009] A method for manufacturing a double-walled prismatic battery cell comprises folding a metal sheet to form an inner casing of the double-walled prismatic battery cell, and folding the metal sheet to form an outer casing of the double-walled prismatic battery cell around the inner casing, wherein an air gap is disposed between the outer casing and the inner casing. The outer casing includes a first and a second opening. The method comprises arranging a battery cell stack within the inner casing, attaching a first lid portion to a first opening of the outer casing, and attaching a first bottom portion to a second opening of the outer casing.

[0010] For other features, the battery cell stack includes A anode electrodes, C cathode electrodes, and S separators, where A, C, and S are integers greater than one.

[0011] In other features, the method includes using a first and a second roller to create a first pattern of stiffening sections on a first side of the outer casing and a second pattern of stiffening sections on a second side of the outer casing. The first pattern of stiffening sections and the second pattern of stiffening sections are different. The first pattern of stiffening sections and the second pattern of stiffening sections are offset to enable nesting of the dual-walled prismatic battery cell with one or more adjacent dual-walled prismatic battery cells. The first pattern of stiffening sections includes depressions having a rectangular and / or an arcuate cross-section. The first pattern of stiffening sections includes stiffening beads.

[0012] In other features, the method includes disposing thermally conductive material in the gap.

[0013] In other features, the method includes enclosing a third opening of the inner housing with a second lid portion prior to attaching the first lid portion. In other features, the method includes enclosing a fourth opening of the inner housing with a second bottom portion prior to attaching the first bottom portion.

[0014] In other features, the method includes providing a vent opening on at least one of the first lid portion and the first bottom portion.

[0015] Further areas of applicability of the present disclosure will become apparent from the detailed description, claims, and drawings. The detailed description and specific examples are for illustrative purposes only and are not intended to limit the scope of the disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present disclosure will be more fully understood from the detailed description and the accompanying drawings, in which: Fig. 1 shows an example of a battery cell with cathode electrodes, anode electrodes and separators arranged in a battery cell housing according to the present disclosure in a cross-sectional side view, Fig. 2A shows an example of a prismatic battery cell in a perspective view, Fig. 2B shows an example of a prismatic battery cell with a pressure-assisted vent cap in a perspective view, Fig. 3A shows an example of a plurality of prismatic battery cells with a thermal insulation material arranged therebetween in a perspective view, Fig. 3B shows an example of a plurality of double-walled prismatic battery cells without any thermal insulation material arranged therebetween according to the present disclosure in a perspective view, Fig. Figure 3C shows a graph illustrating the thermal conductivity as a function of temperature for air and aerogel, Fig. 4A to 4F show examples of double-walled prismatic battery cells with stiffening sections according to the present disclosure, each in a perspective view, Fig. 5A and Fig. 5B show side views illustrating examples of stiffening sections on adjacent double-walled prismatic battery cells according to the present disclosure, Fig. 5C is a side view illustrating an example of side walls at locations without stiffening sections according to the present disclosure, Fig. 5D shows a side view illustrating an example of sidewalls with thermal interface material according to the present disclosure, Fig. 6A shows a perspective view illustrating an example of manufacturing the double-walled prismatic battery cell according to the present disclosure, Fig. 6B shows a plan view illustrating an example of manufacturing the double-walled prismatic battery cell according to the present disclosure, Fig. 7A to 7C show perspective views illustrating an example of the manufacture of the double-walled prismatic battery cell during folding according to the present disclosure, Fig. 8A and Fig. 8B show examples of double-walled prismatic battery cells according to the present disclosure, each in an exploded view, Fig. 9 and Fig. 10 show examples of a plurality of double-walled prismatic battery cells arranged on a thermally conductive material and a cooling plate according to the present disclosure, each in a perspective view, Fig. 11 and Fig. 12 illustrate examples of a contact surface between the thermal interface material and the cooling plate according to the present disclosure, and Fig. 13 and Fig. 14 show examples of a plurality of double-walled prismatic battery cells and a thermal interface material and a cooling plate according to the present disclosure, each in a perspective view.

[0017] Reference symbols may be reused in the drawings to identify similar and / or identical elements. DETAILED DESCRIPTION

[0018] While double-walled prismatic battery cells according to the present disclosure are shown in the context of electric vehicles, the double-walled prismatic battery cells may also be used in stationary applications and / or other applications.

[0019] Aerogels have previously been used as thermal insulation materials to prevent thermal runaway or thermal propagation between adjacent battery cells. The present disclosure relates to prismatic battery cells comprising a double-walled prismatic casing with an insulating layer of air between the inner and outer walls of the casing. At high temperatures, air has a lower thermal conductivity than aerogels.

[0020] The air gap acts as a "virtual" thermal barrier material to delay heat transfer from the inner wall to the outer wall, thereby reducing or preventing heat spread to adjacent battery cells. The inner walls of the double-walled prismatic enclosure have a flat surface that contacts the outer surfaces of the battery stack (e.g., jellyroll or cell electrode stack). In some examples, the outer walls are provided with stiffening beads (or dimples) to increase rigidity and reduce expansion of the enclosure. In some examples, the double-walled prismatic enclosure is formed by a roll-forming process followed by welding. One or more lid and / or base panels enclose the outer and / or inner double-walled prismatic enclosure.

[0021] In some examples, the double-walled prismatic package is manufactured using cost-effective bending and crimping processes similar to those used for soup cans. This process can be applied to large form-factor cells. The double walls of the double-walled prismatic package also provide energy absorption.

[0022] With reference now to Fig. 1, a battery cell 10 comprises C cathode electrodes 20, A anode electrodes 40, and S separators 32, which are arranged in a predetermined order in a stack 12 located in a housing 50. The C cathode electrodes 20-1, 20-2, ... and 20-C (where C is an integer greater than one) comprise cathode active layers 24 arranged on one or both sides of cathode current collectors 26. The A anode electrodes 40-1, 40-2, ... and 40-A (where A is an integer greater than one) comprise anode active layers 42 arranged on one or both sides of the anode current collectors 46.

[0023] In some examples, the anode active layers 42 and / or the cathode active layers 24 are freestanding electrodes disposed adjacent to (or attached to) the current collectors. In some examples, the anode active layers 42 and / or the cathode active layers 24 include coatings comprising one or more active materials, one or more conductive fillers / additives, and / or one or more binders. In some examples, the battery cells and / or electrodes are manufactured by applying a slurry to coat the current collectors in a roll-to-roll process. In some examples, the cathode current collectors 26 and / or the anode current collectors 46 include a foil layer. In some examples, the current collectors are made from one or more materials selected from the group consisting of copper, stainless steel, brass, bronze, zinc, aluminum, and their alloys.

[0024] With reference now to Fig. 2A and Fig. 2B, a prismatic battery cell 58 includes a housing 60. The housing 60 includes a single wall. In some examples, the housing 60 has a rectangular cross-section in the x-, y-, and z-axis planes. The housing 60 includes a can body 61 having sides 80 and sides 82 forming an open, rectangular cube.

[0025] A lid portion 84 and a bottom portion 86 are attached to the can body 61 to enclose the top and bottom openings of the can body 61, respectively. The prismatic battery cell 58 includes external terminals 62 and 64 that pass through the lid portion 84. The stack 12 of the C cathode electrodes 20, the A anode electrodes 40, and the S separators 32 is arranged in the housing 60.

[0026] The outer terminals 62 and 64 are connected to the outer tabs of the A anode electrodes 40 and the C cathode electrodes 20, respectively. Fig. 2A, the cover portion 84 does not include a pressure-assisted vent cap. In Fig. 2B, the lid portion 84 (and / or the base portion 86) includes a pressure-assisted vent cap 66. The pressure-assisted vent cap 66 is configured to release vent gases when the pressure within the inner housing is greater than a predetermined pressure.

[0027] With reference now to Fig. 3A shows a plurality of single-wall prismatic battery cells 60-1, 60-2, ..., and 60-B (where B is an integer greater than one). A thermal insulation material 90 is disposed between the side surfaces (e.g., sides 82) of adjacent single-wall prismatic battery cells 60-1, 60-2, ..., and 60-B. In some examples, the thermal insulation material 90 comprises aerogel or other suitable thermal insulation material. The thermal insulation material 90 is used to reduce heat transfer between the plurality of single-wall prismatic battery cells 60-1, 60-2, ..., and 60-B, thereby reducing thermal runaway or thermal propagation. However, the thermal insulation material is expensive.

[0028] In Fig. 3B, double-walled prismatic battery cells 94 according to the present disclosure include an inner housing connected to and disposed within an outer housing. The battery stack is disposed within the inner housing. An air gap is located between the inner housing and the outer housing. The air gap reduces heat transfer from one battery cell to adjacent battery cells. Fig. 3B shows a plurality of double-walled prismatic battery cells 94-1, 94-2, ..., and 94-B without the thermal insulation material disposed therebetween. The air gap of the double-walled prismatic battery cells 94 provides a thermal barrier that prevents the transfer of heat from one prismatic battery cell to an adjacent battery cell and consequently reduces the likelihood of thermal runaway or thermal propagation. In other words, in some examples, the thermal insulation material can be omitted, reducing costs.

[0029] With reference now to Fig. Figure 3C shows the thermal conductivity of aerogel and air as a function of temperature. As temperature increases, the thermal conductivity of aerogel increases significantly more than that of air. At higher temperatures, where thermal runaway occurs, air is a much better insulator than aerogel. In other words, aerogel transfers heat faster than air (when one cell heats up, neighboring battery cells heat up more when aerogel is used compared to air).

[0030] With reference now to Fig. 4A through 4F, a double-walled prismatic battery cell 94 is shown having a plurality of stiffening sections 122. While the stiffening sections include recesses, the stiffening sections 122 may also have other shapes, such as ridges or other shapes. In some examples, the stiffening sections 122 are arranged in a predetermined pattern 120 on a side surface 128 of an outer casing 132 of the double-walled prismatic battery cell 94.

[0031] In Fig. 4A, the stiffening sections 122 include recesses extending outwardly from the side surface 128 of the outer casing 132. A side surface 134 of an inner casing 136 is disposed adjacent to and spaced from the side surface 128 of the outer casing 132 to form an air gap 133 therebetween. The air gap 133 acts as insulation to reduce heat transfer between adjacent double-walled prismatic battery cells. In Fig. 4B, the stiffening sections 122 are arranged in a first predetermined pattern 120-1 on one of the side surfaces 128 of the outer housing 132. In Fig. 4C, the stiffening sections 122 are arranged in a second predetermined pattern 120-1 on an opposite one of the side surfaces 128 of the outer housing 132.

[0032] In Fig. 4D to 4F, the stiffening sections 122 comprise stiffening ribs that extend vertically or horizontally. The stiffening sections 122 are arranged in a first predetermined pattern 120-3 on one side of the double-walled prismatic battery cell 94 and a second predetermined pattern 120-4 on an opposite side surface of the double-walled prismatic battery cell 94.

[0033] In some examples, the first predetermined pattern and the second predetermined pattern are identical. In other examples, the stiffening portions of the first predetermined pattern and the second predetermined pattern are different. For example, the stiffening portions on one side are offset relative to the stiffening portions on the opposite side to enable nesting of the stiffening portions 122 with adjacent prismatic battery cells. In other words, adjacent cells of the dual-walled prismatic battery cells may be arranged in close proximity (e.g., the stiffening portions are arranged in a nested pattern when aligned and / or positioned adjacent to one another).

[0034] With reference now to Fig. 5A and Fig. 5B shows further examples of the stiffening sections 122. In Fig. 5A, the stiffening sections 122 are arranged on side surfaces of adjacent double-walled prismatic battery cells and include the first predetermined pattern and the second predetermined pattern, which are different to allow nesting. In Fig. 5A, the stiffening sections 122 have a rectangular or polygonal shape. In Fig. 5B, the stiffening sections 122 have an arcuate or semicircular shape.

[0035] In Fig. 5C, the sidewalls of the outer housing 132 and the inner housing 136, respectively, may include recesses or beads 135 that help maintain the spacing of the air gap 133. In some examples, recesses or beads 135 extend inwardly on the sides or ends of the outer housing 132 and / or the inner housing 136 to maintain the dimensions of the air gap 133 between the sidewalls of the outer housing 132 and the inner housing 136, respectively.

[0036] In Fig. 5D, the sidewalls of the outer housing 132 and the inner housing 136 are shown with a thermal interface material 150 at spaced locations to enhance heat transfer from the interior of the double-walled prismatic battery cell 94 to the outer housing 132 when cooling is used. The thermal interface material 150 may also be disposed at locations with the stiffening sections and / or continuously fill volumes between the sidewalls of the outer housing 132 and the inner housing 136, respectively.

[0037] With reference now to Fig. 6A to 7C show the production of the double-walled prismatic battery cell. Fig. 6A, a metal sheet 214 is optionally trimmed at 216 and then pressed between the first roller 220 and the second roller 222. In some examples, the metal sheet is made of steel with a thickness in the range of 0.2 mm to 0.3 mm. In some examples, the stiffening sections have a height of greater than 0.05 mm and less than 1 mm. The first roller 220 includes first and second sets of male projections 224 that correspond to the positions of the stiffening sections of the first and second predetermined patterns. Gaps 226 are located between the first and second sets of male projections 224, which form first and second predetermined patterns 238-1 and 238-2 of the stiffening sections 240.

[0038] The second roller 222 includes a first and a second set of female cavities 228 that correspond to the positions of the first and second predetermined sets of male projections 224. Gaps 229 are located between the first and second sets of female cavities 228. The first and second sets of male projections 224 press the metal sheet into the first and second sets of female cavities 228 to form the stiffening sections 240. After passing through the first roller 220 and the second roller 222, the rollers can be trimmed at 240, if necessary. The metal sheet 214 is cut to length at 244. The process is repeated for other double-walled prismatic battery cell casings.

[0039] It should be noted that the circumference of the first and second rollers may be equal to the length of a steel blank for the double-walled prismatic housing (or a multiple thereof). The outer surface of the first roller 220 and the second roller 222 may include patterns for N of the double-walled prismatic housings, where N is an integer. Fig. 6A, N = 1. The circumference of the first roller 220 and the second roller 222 increases with N.

[0040] In Fig. 6B shows a double-walled housing 300 for a prismatic battery cell. The double-walled housing 300 includes the sides 320, 322, 324, and 326 of an outer housing 330 and the sides 340, 342, 344, and 346 of an inner housing 350. The metal sheet is folded along fold lines 360 to form the inner housing 350. The metal sheet is then folded along fold lines 370 to form the outer housing 330. Optionally, additional material 380 can be used to provide a gap between the outer housing 330 and the inner housing 350.

[0041] In Fig. 7A to 7C, the metal sheet 214 is folded along the fold lines 360 to form the inner housing 350. Thereafter, the metal sheet 214 is folded along the fold lines 370 to form the outer housing 330. In Fig. 7C, side 320 is welded at 390.

[0042] With reference now to Fig. 8A and Fig. 8B shows examples of double-walled prismatic battery cells 400 and 450, respectively. Fig. 8A, the double-walled prismatic battery cell 400 includes a lid portion 410 and a bottom portion 414 that enclose first and second openings of an inner housing 420 and an outer housing 422. The lid portion 410 and the bottom portion 414 may be crimped and / or welded (e.g., laser welded).

[0043] In Fig. 8B, the double-walled prismatic battery cell 450 includes a first lid portion 460 and a first bottom portion 464 that enclose first and second openings of an inner housing 470. The double-walled prismatic battery cell 450 includes a second lid portion 480 and a second bottom portion 484 that enclose first and second openings of an outer housing 486.

[0044] The first cover portion 460 may include holes 492 to allow the terminals 488 and 490 to pass through the first cover portion 460. A hole 494 in the first cover portion 460 ensures that a vent cap 498 in the second cover portion 480 is in fluid communication with an internal volume of the inner housing 470. A hole 496 allows electrolyte to be introduced into the inner housing 470.

[0045] With reference now to Fig. 9 and Fig. 10 shows examples of cooling plates. In Fig. 9, a plurality of double-walled prismatic battery cells 500-1, 500-2, ..., and 500-B are arranged on a thermal interface material 520 and a cooling plate 524 to cool the bottom surfaces of the plurality of double-walled prismatic battery cells 500-1, 500-2, ..., and 500-B. The plurality of double-walled prismatic battery cells 500-1, 500-2, ..., and 500-B include terminals 512 and 514 on the top surfaces of the plurality of double-walled prismatic battery cells 500-1, 500-2, ..., and 500-B opposite the bottom surfaces.

[0046] In Fig. 10, a plurality of double-walled prismatic battery cells 600-1, 600-2, ..., and 600-B are disposed on the thermal interface material 520 and the cooling plate 524 to cool the bottom surfaces of the plurality of double-walled prismatic battery cells 600-1, 600-2, ..., and 600-B. The plurality of double-walled prismatic battery cells 600-1, 600-2, ..., and 600-B include terminals 612 and 614 on the side surfaces of the plurality of double-walled prismatic battery cells 600-1, 600-2, ..., and 600-B adjacent to the bottom surfaces.

[0047] With reference now to Fig. 11 and Fig. 12, examples of a contact surface between a bottom of the double-walled prismatic battery cell and the thermal interface material 520 and the cooling plate 524 are shown. In Fig. 11, a double-walled prismatic battery cell 700 includes an inner casing 710 and an outer casing 712. An air gap 714 is formed between the inner casing 710 and the outer casing 712. If the bottom of the inner casing 710 and the outer casing 712 are flat, the thermal interface material 520 and the cooling plate 524 may be flat.

[0048] In Fig. 12, a double-walled prismatic battery cell 800 includes an inner casing 810 and an outer casing 812. An air gap 814 is formed between the inner casing 810 and the outer casing 812. When the bottom of the inner casing 810 and the outer casing 812 are mechanically joined (double-seamed or crimped) to form a recess at 820, the thermal interface material 520 includes portions 830 that extend into the recesses 820 to maintain thermal communication. The cooling plate 524 includes a protrusion 840 that extends into the portions 830 and / or the recesses 820.

[0049] With reference now to Fig. 13 and Fig. 14 shows further examples of cooling a variety of double-walled prismatic battery cells. In Fig. 13, B double-walled prismatic battery cells 900-1, 900-2, ..., and 900-B are arranged in an array having a plurality of horizontal rows and a plurality of vertical rows. A cooling structure 918 having a cooling plate 920 sandwiched between thermally conductive material 922 is disposed between adjacent ends 930 of the double-walled prismatic battery cells 900-1, 900-2, ..., and 900-B located in adjacent vertical rows. In this example, the terminals are disposed on a top surface of the double-walled prismatic battery cells 900-1, 900-2, ..., and 900-B. In some examples, a thermally conductive material is disposed between the inner housing and the outer housing along a narrow edge of the battery cells.

[0050] In Fig. 14, double-walled prismatic battery cells 950-1, 950-2, ..., and 950-B are arranged adjacent to one another in a single row. The cooling structure 918 (e.g., including the cooling plate 920 sandwiched between the thermally conductive material 922) is disposed between the sides of adjacent double-walled prismatic battery cells 900-1, 900-2, ..., and 900-B. In some examples, the stiffening portions are disposed on the thermally conductive material 922. In this example, the terminals are disposed on an end face of the double-walled prismatic battery cells 900-1, 900-2, ..., and 900-B. In some examples, a thermally conductive material is disposed between the inner casing and the outer casing along a wide side of the battery cells.

[0051] The above description is merely illustrative and is not intended to limit the disclosure, its application, or uses in any way. The broad teachings of the disclosure may be embodied in a variety of forms. Therefore, while this disclosure includes specific examples, the true scope of the disclosure should not be limited thereto, since other changes will become apparent after studying the drawings, the patent specification, and the following claims. It is understood that one or more steps within a method may be performed in different orders (or simultaneously) without altering the principles of the present disclosure.Furthermore, although the embodiments are each described above as having specific features, any one or more of these features described with respect to one embodiment of the disclosure may be implemented and / or combined with features of any of the other embodiments, even if this combination is not explicitly described. In other words, the described embodiments are not mutually exclusive, and interchange of one or more embodiments remains within the scope of this disclosure.

[0052] Spatial and functional relationships between elements (e.g., between modules, circuit elements, semiconductor layers, etc.) are described using various terms, including "connected," "engaging," "coupled," "adjacent," "beside," "on top of," "over," "below," and "disposed." If a relationship between first and second elements is not explicitly described as "direct" in the above disclosure, that relationship may be a direct relationship, with no other intervening elements between the first and second elements, or an indirect relationship, with one or more intervening elements (either spatial or functional) between the first and second elements.As used herein, the term “A, B and / or C” should be construed as logical (A ORed with B ORed with C) using a non-exclusive logical OR and should not be understood as “at least one of A, at least one of B and at least one of C”.

[0053] In the figures, the direction of an arrow, as indicated by the arrowhead, generally illustrates the flow of information (e.g., data or instructions) of interest to the illustration. For example, if element A and element B exchange a lot of information, but the information passed from element A to element B is relevant to the illustration, the arrow may point from element A to element B. This unidirectional arrow does not imply that no other information is passed from element B to element A. Furthermore, for information being sent from element A to element B, element B may send requests for or acknowledgments of receipt of the information to element A.

Claims

[1] Battery cell, comprising: a battery cell stack comprising: A anode electrodes, C cathode electrodes and S separators, where A, C and S are integers greater than one, and a double-walled prismatic housing adapted to accommodate the battery cell stack, comprising: a can body with an inner casing, an outer casing and a gap between the inner casing and the outer casing, wherein the battery cell stack is arranged in the inner housing, wherein the outer casing of the can body defines a first opening and a second opening at its opposite ends, a first cover part attached to the first opening of the outer casing, and a first bottom part attached to the second opening of the outer casing. [2] The battery cell of claim 1, wherein a first side of the outer casing comprises a plurality of stiffening sections arranged in a first pattern. [3] Battery cell according to claim 2, wherein: a second side of the outer casing comprises a plurality of stiffening sections arranged in a second pattern, and the first pattern and the second pattern are different. [4] The battery cell of claim 3, wherein the first pattern and the second pattern are offset to enable nesting of the battery cell with one or more adjacent battery cells. [5] Battery cell according to claim 2, wherein the plurality of stiffening sections comprise depressions and / or stiffening beads. [6] Battery cell according to claim 5, wherein the recesses have a rectangular or an arcuate cross-section. [7] The battery cell of claim 1, further comprising a thermally conductive material disposed in the gap between the inner casing and the outer casing. [8] Battery cell according to claim 1, further comprising: a second cover part enclosing a third opening of the inner housing, and a second bottom portion enclosing a fourth opening of the inner housing. [9] The battery cell according to claim 1, wherein at least one of the first lid part and the first bottom part has a vent opening. [10] System comprising: a plurality of battery cells according to claim 1, a cooling plate, a thermally conductive material disposed between the cooling plate and a first of the plurality of battery cells and a second of the plurality of battery cells.

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