SEGMENTED BURST VALVES

Abstract

Cylindrical energy storage device comprising a round lid, the lid comprising a cover plate with a center point and an outer rim, and a plurality of burst valves.

Description

Technical field The invention relates to a cylindrical energy storage device and a method for manufacturing a cylindrical energy storage device. background Energy storage devices capable of releasing energy in the form of electrical current (colloquially also referred to as "electricity storage") are indispensable in modern life. In particular, energy storage devices in the form of capacitors or batteries, such as accumulators, are found in a wide variety of applications. Energy storage devices are able to store energy by charging it with electricity and can then release this energy as electricity to a suitable consumer by discharging it. Energy storage devices, often based on lithium, are used in a variety of applications, including smaller, mobile devices such as watches, mobile phones, tablets, and laptops, as well as serving as energy sources to power vehicles such as hybrid vehicles, electric vehicles, e-bikes, ships, trains, and even airplanes. Electric vehicles, in particular, often utilize a variety of energy storage systems in combination. These energy storage devices can take on a wide variety of geometries. A common geometry is cylindrical. In cylindrical energy storage devices, also called cylindrical cells, energy is typically stored in a so-called jelly roll. A jelly roll generally consists of an anode foil and a cathode foil, with the two foils arranged one on top of the other. Direct contact is prevented by a separator layer (also called a "separator"), and the stacked foils are wound around a core. The jelly roll is also usually at least partially surrounded by a liquid electrolyte, in which it is mostly immersed. The jelly roll is electrically connected via current collectors, which are typically attached to the jelly roll with a rivet.The current collectors also provide an electrical connection to so-called terminals, the terminals in turn providing an electrical connection to an application to be operated. The applications of energy storage systems generally place high demands on their safe and reliable operation. In particular, a suitable design of the energy storage system is intended to prevent a so-called "thermal runaway," i.e., a thermal runaway of the energy storage device. During a thermal runaway, the temperature within the energy storage system rises, initially usually continuously, but after a certain tipping point transitions into exponential growth that can no longer be stopped. The increasing temperature also causes volatile electrolyte components to evaporate, leading to gas and pressure buildup within the energy storage system and potentially resulting in ignition and / or rupture of the entire system.Therefore, energy storage devices are typically equipped with safety valves that open in the event of thermal runaway, allowing the released gas to escape. A safety valve is usually located in the lid of the energy storage device, which is typically connected to a housing, also called a "can," and / or to the jelly roll, for example, by crimping, flaring, or welding. The safety valve itself is usually circular and has an annular indentation that serves as a "weak point."Depending on where thermal runaway occurs within the energy storage system, current safety valve configurations may not optimally cover the local point where thermal runaway begins (a so-called "local hotspot"). This means that a sufficiently high pressure must first build up locally at the hotspot within the energy storage system before it can propagate through the energy storage system to the safety valve and cause it to burst. This leads to a pressure buildup within the energy storage system, which, while only localized, is generally undesirable. For more reliable protection against thermal runaway, the safety valve would therefore need to cover a large area of ​​the lid.However, this leads to a drastic loss of structural rigidity in the lid itself, so that the lid and the safety valve deform elastically or plastically rather than opening. Furthermore, a larger safety valve offers less space for contact with the jelly roll. Accordingly, a connection between the lid and, for example, the jelly roll is only possible via a few and short welds, which, however, leads to a weaker connection and an overall more fragile structure of the energy storage device. There is therefore a need for improved energy storage devices, in particular cylindrical energy storage devices, which have an improved safety profile, especially against thermal runaway, as well as methods for manufacturing such energy storage devices, in particular cylindrical energy storage devices, which reduce at least some, ideally all, of the aforementioned disadvantages of known energy storage devices and ideally overcome them completely. Summary The above-mentioned problem is solved by a cylindrical energy storage device comprising a round lid, wherein the lid includes a cover plate, having a center point and an outer rim, and a plurality of burst valves. Furthermore, the present invention provides a method for manufacturing the described cylindrical energy storage device. Figures Fig. 1 shows a perspective cross-sectional view of the top surface of an embodiment of the energy storage device lid with a plurality of rupture valves. Fig. 2 shows a perspective cross-sectional view of the top surface of another embodiment of the energy storage device lid with a plurality of rupture valves. Fig. 3 shows a perspective cross-sectional view of the bottom surface of an embodiment of the energy storage device lid with a plurality of rupture valves. Detailed description According to a first aspect of the present invention, a cylindrical energy storage device is described which comprises a round lid, wherein the lid comprises a lid plate having a center point and an outer edge, and a plurality of burst valves. The term "energy storage device," as used herein, refers to an energy storage device capable of releasing energy in the form of electrical current (colloquially also referred to as an "electricity storage device"). The energy storage device can be, for example, a capacitor or a battery, where the battery can be a primary battery (for a single discharge) or an accumulator (for multiple charge and discharge cycles). Preferably, the energy storage device is a battery, and particularly preferably an accumulator. Surprisingly, it was demonstrated that the cylindrical energy storage device according to the invention enables an improved and, in particular, more precise response from rupture valves in the event of thermal runaway. Specifically, it was found that individual rupture valves react better to local hotspots during thermal runaway than a single, larger rupture valve. The multiple rupture valves in the lid thus significantly improve safety during thermal runaway by reliably providing the released gas with the shortest path to escape from the energy storage device, preventing other areas of the energy storage device from being excessively exposed to the hot gas and the resulting pressure over an extended period. This substantially reduces the risk of rupture and ignition of the entire energy storage device.Furthermore, it has been found that the structure of a lid with a plurality of burst valves is structurally significantly stiffer compared to a conventional lid with only one burst valve. This means that the lid in the energy storage device according to the invention is more stable against external forces than a conventional lid, such as torsion, vibration, pressure, or bending. Because the lid in the energy storage device according to the invention does not deform under the influence of a force, or at least deforms considerably less than conventional energy storage devices, one or more welds between the lid and the adjacent jelly roll remain intact in the event of thermal runaway, which has a positive effect on the overall stability of the energy storage device.Because the lid can be spatially arranged at a lower end of the energy storage device, several advantages arise when using the energy storage devices according to the invention. For example, the energy storage device, or multiple energy storage devices, in an electric vehicle can be arranged so that the lid points away from the vehicle interior, for example, downwards towards the road. This means that in the event of thermal runaway, the multiple rupture valves open in the opposite direction to any vehicle occupants. Likewise, the use of multiple rupture valves allows them to open within a smaller pressure tolerance range than with just one rupture valve, as in conventionally used energy storage device lids. In other words, opening the rupture valves with multiple rupture valves is more controlled and reliable compared to using only one.It is therefore possible to set a specific pressure at which a first burst valve opens much more precisely and easily. It has been shown that arrangements with a plurality of burst valves in the energy storage device according to the invention result in a lower tolerance for a predetermined and desired burst pressure of 15 bar (at which at least one safety valve opens) of 15 bar ± 1 bar or less, using conventional manufacturing techniques, whereas individual safety valves typically have a tolerance of ± 2 bar. The terms "cylindrical" and "round," as used herein in connection with the energy storage device and the lid, respectively, mean that the respective objects are essentially cylindrical and essentially round. In other words, the terms "cylindrical" and "round," as used herein, also include minor deviations from the respective perfectly cylindrical and round geometric shapes. For example, "round" may also include slightly elliptical shapes. Thus, the lid, for instance, may include all round and elliptical shapes whose largest radius differs from their smallest radius by a maximum of 20%, preferably a maximum of 10%, more preferably a maximum of 5%, and most preferably a maximum of 2%.For example, "round" can also include polygons with a plurality of vertices, wherein the interior angles of all vertices can be equal, and the number of vertices is at least 8, preferably at least 10, more preferably at least 12, for example 8 to 20, more preferably 10 to 18, and even more preferably 12 to 16. In some preferred embodiments, "round" means circular. Likewise, the top surface of the cylinder can, for example, comprise all round or elliptical shapes whose largest radius differs from their smallest radius by a maximum of 20%, more preferably a maximum of 10%, more preferably a maximum of 5%, and most preferably a maximum of 2%, or polygons as described above. In some preferred embodiments, "cylindrical" means that the top surface of the cylinder is circular. In one embodiment, the plurality of rupture valves comprises 3 to 20 rupture valves. It can be particularly advantageous for the cover to have 5 to 12 rupture valves, preferably 6 to 10, as this gives the cover excellent structural rigidity, thus significantly increasing its overall robustness. At the same time, a number of 5 to 12 rupture valves, preferably 6 to 10, provides optimal coverage of the energy storage device with regard to potential local points of thermal runaway. Furthermore, this number has proven suitable for simultaneously providing a means of gas escape in the event of gas evolution, in the form of the then-opening rupture valve(s) of a sufficiently large size. For example, the cover can have 7 to 9 rupture valves. In some embodiments, the cover has, for example, 8 rupture valves. The shape of rupture valves is not limited and can assume any conceivable geometry. For example, the shape of rupture valves can be round, oval, elliptical, nearly circular, circular, triangular, rectangular, square, pentagonal, hexagonal, heptagonal, or more than heptagonal, or at least a portion of any of these shapes. For example, the shape of rupture valves can be sector-shaped or segment-shaped. The corners of the segments or sectors can also be rounded. The multiple rupture valves can all have the same shape, or the shapes of individual or all rupture valves within the multiple can differ.In preferred embodiments, the plurality of burst valves each have a circular sector shape, optionally with rounded corners, wherein preferably an arc-shaped section (the circular arc) of the plurality of burst valves runs, usually on a concentric path, along the outer edge of the lid. The bursting valves preferably have a circular sector shape, optionally with rounded corners; that is, they are shaped like a segment of a circle bounded by an arc and two radii. The arcuate portion of the circular segment preferably runs, typically along a concentric path, along the outer edge of the lid. The multiple bursting valves are preferably arranged so close to one another that their tips point towards the center. The tips of the bursting valves can be pointed or rounded. In one embodiment, the energy storage device or the cover includes a recess, wherein the center point of the recess is preferably located at the center point of the cover plate. The recess at the center of the lid can have any conceivable geometry. For example, the shape of the recess at the center of the lid can be round, oval, elliptical, nearly circular, circular, triangular, rectangular, square, pentagonal, hexagonal, heptagonal, or more than heptagonal, preferably circular. The recess can have a height extending from the lid in a direction along an axis perpendicular to the lid and located at its center, for example, in the direction of a jelly roll. The height of the recess can correspond to the thickness of the lid. However, the edge of the recess can also be reinforced so that the thickness of the edge of the recess is at least 1.1 times the thickness of the lid, and preferably at least 1.2 times the thickness of the lid.The thickness of the recess's edge is typically no more than twice the material thickness of the cover plate, and preferably no more than 1.5 times the material thickness of the cover plate. The recess has a cross-sectional area of ​​at least 5% of the cover plate's base area, preferably at least 7.5%, and more preferably at least 10%. Typically, the cross-sectional area of ​​the recess is no more than 20% of the cover plate's base area, preferably no more than 17.5%, and more preferably no more than 15%. The recess at the center of the cover plate can be used to align the energy storage device with a corresponding protrusion in the base plate of a battery housing by placing the energy storage device with the recess onto the protrusion.In some embodiments, the energy storage device or the cover includes a circular or substantially circular recess, preferably with the center of the recess being located at the center of the cover plate. In one embodiment, each of the plurality of burst valves comprises a burst valve rim, wherein the burst valve rim has a height extending from the underside of the cover plate, a burst valve surface, and an indentation. The height of the rupture valve rim of each rupture valve also defines the position of the rupture valve surface. The height of the rupture valve surface can essentially correspond to the height of the rupture valve rim, in each case relative to the underside of the cover plate. It can be advantageous for the ratio of the height of the rupture valve rim to the height of the outer edge of the cover plate to be 2:1 to 1:2, preferably 1.75:1 to 1:1.75, more preferably 1.5:1 to 1:1.5, even more preferably 1.25:1 to 1:1.25, and particularly preferably 1:1, measured from the cover plate. The indentation forms the predetermined breaking point of the rupture valve. For this purpose, the indentation has a material thickness of at most 90%, preferably at most 75%, more preferably at most 60%, even more preferably at most 50%, further preferably at most 35%, and still more preferably at most 25%, compared to the surface of the rupture valve. Due to the reduced material thickness of the indentation compared to the surface of the rupture valve, the material in the indentation area can withstand less pressure than in the surrounding areas. As a result, the material yields at the indentation, and the rupture valve opens when the pressure inside the energy storage device increases. The rupture valve opens outwards, or in other words, it opens in the direction of the pressure acting upon it. For example, the rupture valve may be partially or completely separated from the lid when opened by a pressure increase. Furthermore, a transition between the cover plate and the rupture valve rim can have a concave curve, which can extend around the entire rupture valve. The transition between the rupture valve rim and the rupture valve surface can have a convex curve, which can also extend around the entire rupture valve. In one embodiment, the indentation has a plurality of depressions, and the plurality of depressions comprises at least three depressions that converge centrally, for example, from the three corners of a sector-shaped or segment-shaped rupture valve, thereby defining at least a first, a second, and a third rupture valve segment. In embodiments, however, four or more, for example, five or six rupture valve segments can also be defined by a corresponding number of depressions. Three rupture valve segments have proven to be particularly preferred. The recesses can form part of the predetermined breaking point(s) of the rupture valve. For this purpose, the recesses, individually or independently of one another, have a material thickness of at most 90%, preferably at most 75%, more preferably at most 60%, even more preferably at most 50%, further preferably at most 35%, and most preferably at most 25%, compared to the surface of the rupture valve. The shape of the individual rupture valve segments is defined by the recesses. The individual rupture valves can each have the same shape or be partially identical; for example, a first rupture valve segment and a second rupture valve segment can be identical or mirror images, or the rupture valve segments can each have a different shape. The material thickness can also vary within a single recess.For example, the material thickness within a depression can decrease continuously towards the central point where several depressions converge. The rupture valve rim can also serve as a hinge. If the pressure in an energy storage device increases, the central point where the depressions converge can form the intended weakest point in the assembly. As the pressure increases, the segments first flex and then rupture at a certain internal pressure. During this process, the individual segments fan out from the central point. The rupture valve rim then acts as a hinge, allowing the individual segments to unfold. The segments themselves can be bent during this unfolding or essentially retain their flat structure. In one embodiment, the rupture valve additionally comprises a circumferential recess located between the rupture valve rim and the rupture valve surface. The circumferential recess can have the thickness described above. In a preferred embodiment, however, its thickness is greater than the thickness of the multiple recesses converging at the central point. In one embodiment, the recesses between the at least first, second and third burst valve segment are deeper than the circumferential recess starting from the burst valve surface. The circumferential recess of the rupture valve can act as a hinge. As the pressure in an energy storage device increases, the central point where the recesses converge forms the intended weakest point in the assembly. With increasing pressure, the segments first flex and then rupture at a certain internal pressure. During this process, the individual segments fan out from the central point. The circumferential recess then acts as a hinge, allowing the individual segments to unfold. The segments themselves can either bend during this unfolding or essentially retain their flat structure. At least one rupture valve may have a recess. The shape of the recess is not limited and may be round, oval, elliptical, nearly circular, circular, triangular, rectangular, square, pentagonal, hexagonal, heptagonal, or more than heptagonal. In some embodiments, at least one rupture valve segment has a circular recess. The recess may serve to align the energy storage device against a corresponding protrusion by placing the energy storage device with the recess onto the protrusion. Furthermore, the recess may serve as a holding point during the manufacture of the energy storage device. Additionally, the recess may be used to align the components of the lid or the energy storage device during manufacturing, for example, for a welding process. In one embodiment, a recess or channel is defined on the cover plate between each pair of adjacent burst valves, wherein a plurality of channels can extend in a star shape from the center of the cover plate, for example from a potentially existing recess in the center of the cover plate towards the outer edge. The multitude of channels can serve as a support geometry for the lid. The arrangement of these channels ensures that the lid, at least in the areas where they are located, is more resistant to twisting, for example, caused by internal pressure within the energy storage unit due to thermal runaway. It is also more resistant to forces exerted on the energy storage unit, particularly the lid, from outside. This significantly enhances the structural integrity of the lid in the channel areas. The structural integrity is influenced by the thickness of the channels, with greater thickness resulting in greater lid stiffness.The plurality of channels can have a uniform material thickness, wherein the material thickness of the plurality of channels is greater than the material thickness of the rupture valves at any point on a rupture valve segment with a recess. Preferably, the material thickness of the plurality of channels is at least 125% of the material thickness of the rupture valves, more preferably at least 133% of the material thickness of the rupture valves, further preferably at least 150% of the material thickness of the rupture valves, more preferably at least 175% of the material thickness of the rupture valves, even more preferably at least 200% of the material thickness of the rupture valves, even more preferably at least 250% of the material thickness of the rupture valves, and even more preferably at least 300% of the material thickness of the rupture valves. The plurality of channels can have a non-uniform material thickness. For example, the material thickness can increase or decrease from the center point towards the outer edge.Furthermore, the multitude of channels can have alternating material thicknesses, with adjacent channels having different thicknesses. The multitude of channels can also, for example, have non-uniform material thicknesses, decreasing from the center and increasing towards the outer edge. However, a uniform material thickness for the channels is preferred. In particular, it is advantageous for the multitude of channels to have a greater material thickness than the burst valves, since a thinner material yields more readily to pressure than a thicker one. This also achieves a controlled and, in particular, targeted opening of at least one of the burst valves as a predetermined breaking point. The material from which the lid is made is not limited, as long as it can be adequately welded to the housing of the energy storage device and / or a jelly roll. For example, the lid can be made of transition metals, such as iron, copper, nickel, or aluminum, or their alloys, or of steel, or of coated steel, such as nickel-plated steel, with steel, preferably nickel-plated steel, being particularly well-suited for welding to a jelly roll. This results in particularly good weld seams. Furthermore, such a material offers excellent properties for use as a conductive component in an energy storage device. It also exhibits good structural properties, thus contributing to the structural integrity of the lid, especially across the channels.Therefore, covers made of steel, preferably nickel-plated steel, are particularly resistant to external forces. Furthermore, this allows for the creation of areas within the cover, especially the burst valves, that are less resistant to force than other areas, particularly the channels, whereby the material thickness of these areas can be adjusted to meet the required minimum pressures. In preferred embodiments, the lid is made of steel, preferably nickel-coated steel. According to a second aspect of the invention, a method for manufacturing a cylindrical energy storage device is described, comprising casting or milling or deep drawing or extrusion of a lid, wherein the lid is as described above in connection with the first aspect of the invention. The cover can be manufactured by primary forming (e.g., casting), secondary forming (cold extrusion and deep drawing), or machining (milling). Casting and similar primary forming processes can involve casting the cover in one piece. A negative mold of the cover can be provided, into which the liquefied material of the collector is poured and cools. The liquefied material can be a material as described above in connection with the first aspect of the invention. The preformed covers obtained in this way can be cooled. The cooled covers can be deburred and / or polished. Machining processes such as milling can involve clamping a blank into a milling machine. The desired contour is then cut out using various milling tools. The blank can be made of a material as described above in connection with the first aspect of the invention. Steel is the preferred material. Forming manufacturing, primarily but not exclusively limited to cold forming, includes deep drawing and extrusion. Cold forming can involve placing a blank into a cold forming machine. The shaping is achieved by high forces exerted by the presses on the dies and ultimately on the blank. The blank can be made of a material as described above in connection with the first aspect of the invention. Steel is the preferred material. In one embodiment, the method includes arranging the lid on a cylindrical energy storage housing. The lid is positioned on the cylindrical energy storage housing in such a way that it completely covers the housing. The lid can contact a jellyroll, which is located inside the energy storage housing. A current collector, a terminal, and / or electrode connections, for example, can be arranged between the lid and the jellyroll. This arrangement can be achieved via circular recesses provided by one or more rupture valves, with the recesses serving as a retaining element or a reference point. In one embodiment, the method includes welding the lid to the jelly roll and / or the housing. Welding the lid to the jellyroll and / or the housing can be carried out using an industry-standard welding process, such as arc welding, gas metal arc welding, and preferably laser welding. One or more welds formed during the welding process can be arranged on channels, with each channel defined on the lid plate between two adjacent rupture valves. Fig. 1 shows a perspective cross-sectional view of the cover 100 of the energy storage device. The cover 100 comprises a cover plate 110 with a center point 111, an outer edge 112, a recess 115 (the center point 111 being centrally located in the recess 115), and a plurality of rupture valves 120. The cover 100 is a single piece made of one material. The arrangement of the rupture valves 120 relative to each other can also be seen in Fig. 1. Each rupture valve 120 in the plurality of rupture valves 120 has a sector-shaped circular form. The plurality of rupture valves 120 each have a rupture valve rim 121 (the rupture valve rim 121 being a segment of a circle), a rupture valve surface 122, and recesses 123. The transition between the cover plate 110 and each burst valve rim 121 is rounded. The transition between the burst valve rim 121 and the burst valve surface 122 is rounded.The rupture valve rim 121 is angled relative to the cover plate 110 and the rupture valve surface 122. The recesses 123 form the opening sections of each rupture valve 120. The rupture valve surface 122 can be divided into several segments. Figure 1 shows an example of a division into three segments: the first rupture valve segment 124, the second rupture valve segment 125, and the third rupture valve segment 126. The division into the three segments 124, 125, and 126 results in a point where the recesses 123 converge. Furthermore, one or more of the multiple rupture valves has a circular recess 127. The circular recess 127 is arranged on the third rupture valve segment 126, as shown in Figure 1. Channels 130 run between each pair of adjacent burst valves 120. The channels 130 extend from the recess 115 to the outer edge 112.In other words, the channels 130 extend from the recess 115 in a star shape onto the cover plate 110. Fig. 2 shows a perspective cross-sectional view of the cover 100 of the energy storage device in a further embodiment. The cover 100 comprises a cover plate 110 with a center point 111, an outer edge 112, a recess 115, wherein the center point 111 is arranged centrally in the recess 115, and a plurality of burst valves 120. The cover 100 is made in one piece from a single material. Furthermore, the arrangement of the burst valves 120 relative to each other can be seen in Fig. 1. Each burst valve 120 of the plurality of burst valves 120 has a sector-shaped circular form. The plurality of burst valves 120 each have a burst valve rim 121, wherein the burst valve rim 121 is shaped like a circular segment, a burst valve surface 122, and recesses 123. The recesses 123 form the opening sections of a respective burst valve 120. The burst valve surface 122 can be divided into several segments. Fig.Figure 2 shows an example of a division into three segments: the first burst valve segment 124, the second burst valve segment 125, and the third burst valve segment 126. The division into the three segments 124, 125, and 126 results in a point where the recesses 123 converge. The three segments 124, 125, and 126 are further enclosed by a circumferential recess, which is bounded by the rupture valve rim 121. Furthermore, one or more of the multiple burst valves have a circular recess 127. The circular recess 127 is arranged on the third burst valve segment 126, as shown in Figure 1. Channels 130 run between each pair of adjacent burst valves 120. The recesses or channels 130 extend from the opening 115 to the outer edge 112.In other words, the channels 130 extend from the recess 115 in a star shape onto the cover plate 110. Fig. 3 shows the underside of the cover 110. The burst valves 120 have no recesses 123 on their underside, whereas the circular recess 127 protrudes from the plane of the burst valve. Furthermore, the channels 130 are each located on the same plane. Reference symbol list 100 Cover 110 Cover plate 111 Center point 112 Outer edge 115 Recess 120 Burst valve 121 Burst valve edge 122 Burst valve surface 123 Recesses 124 First rupture valve segment 125 Second rupture valve segment 126 Third rupture valve segment 127 Circular recess 130 Channel

Claims

Cylindrical energy storage device comprising a round lid (100), wherein the lid (100) comprises: a lid plate (110) having a center point (111) and an outer rim (112); and a plurality of burst valves (120). Cylindrical energy storage device according to claim 1, wherein the plurality of burst valves (120) comprises 3 to 20 burst valves (120), preferably 4 to 16 burst valves (120), more preferably 5 to 12 burst valves (120) and particularly preferably 6 to 10 burst valves (120). Cylindrical energy storage device according to claim 1 or 2, wherein the plurality of burst valves each have a circular sector shape and each arc-shaped section of the plurality of burst valves extends along the outer edge (112). Cylindrical energy storage device according to one of claims 1 to 3, further comprising: a circular recess (115) wherein the center of the recess (115) is located at the center (111) of the cover plate. Cylindrical energy storage device according to one of claims 1 to 4, wherein each of the plurality of burst valves (120) comprises: a burst valve rim (121), wherein the burst valve rim (121) has a height starting from the cover plate (110); a burst valve surface (122); and an indentation. Cylindrical energy storage device according to claim 5, wherein the indentation has a plurality of depressions (123), and wherein the plurality of depressions comprises: at least three depressions which converge centrally starting from the corners of the circular sector-shaped burst valve (120) and thereby define at least a first, a second and a third burst valve segment (124, 125, 126). Cylindrical energy storage device according to claim 6, wherein the bursting valve (120) comprises a circumferential recess arranged between the bursting valve rim (121) and the bursting valve surface (122). Cylindrical energy storage device according to claim 7, wherein the recesses between the at least first, second and third burst valve segment (124, 125, 126) are deeper than the circumferential recess starting from the burst valve surface (122). Cylindrical energy storage device according to claim 6, 7 or 8, wherein at least one burst valve segment has a circular depression (127). Cylindrical energy storage device according to one of claims 1 to 9, wherein a channel (130) is defined on the cover plate (110) between each of two adjacent burst valves (120), wherein a plurality of the channels (130) extend in a star shape from the recess (115) towards the outer edge (112). Cylindrical energy storage device (100) according to one of claims 1 to 10, wherein the lid (100) is made of steel, preferably nickel-coated steel. Method for manufacturing a cylindrical energy storage device according to any one of claims 1 to 11, comprising: casting or milling or deep drawing or flow drawing of the lid (100).

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