A container and its manufacturing method

Abstract

This application discloses a container and its manufacturing method, comprising: a cylindrical body and an end cap. The cylindrical body has a wall portion, which includes a first outer side, a second outer side, and an inner side. The vertical distance from any position on the first outer side to the inner side of the cylindrical body is defined as d1; the vertical distance from any position on the second outer side to the inner side of the cylindrical body is defined as d2, where d2 < d1. The wall portion has a first mating end face, which connects the first outer side and the second outer side. The end cap includes a mating end, which has a second mating end face and a bottom surface. The bottom surface is positioned opposite to the second outer side. The first mating end face and the second mating end face are mated together. A weld portion is formed by welding the cylindrical body and the end cap at the mating point from the first outer side to the second outer side. The depth of the weld portion is defined as h, where (d1 - d2) < h < d1. This container and its manufacturing method result in a weld with shallow penetration and few weld defects.

Description

Technical Field

[0001] This application relates to the field of air conditioning technology, and in particular to a container and its manufacturing method. Background Technology

[0002] like Figure 1 As shown, in the known related technologies of the inventors, the container body 10 and the end cap 20 are welded together to form a weld 30. In this type of welded structure, the joint between the body and the end cap is relatively thick. In order to ensure the welding quality, a deeper penetration depth (the depth to which the base material melts during welding) is required. When using laser welding on aluminum alloys, the greater the penetration depth, the more defects there are, and the weld may crack and leak, leading to failure. Summary of the Invention

[0003] The purpose of this invention is to provide a container with shallow weld penetration and few weld defects, and a method for manufacturing the same.

[0004] To achieve the above objectives, this application provides a container including a cylindrical body and an end cap. The cylindrical body includes a wall portion, which includes a first outer side surface, a second outer side surface, and an inner side surface. The cylindrical body has an inner cavity, which is formed by the inner side surface surrounding the inner cavity. The first and second outer side surfaces are not in direct contact with the inner cavity, and the inner side surface is closer to the inner cavity than the first and second outer side surfaces. The vertical distance from any position of the first outer side surface to the inner side surface is defined as d1; the vertical distance from any position of the second outer side surface to the inner side surface is defined as d2, where d2 < d1. The wall portion also includes a first mating end face, which connects the first outer side surface and the second outer side surface. The end cap includes a mating end, which has a second mating end face and a bottom surface. The bottom surface is disposed opposite to the second outer side surface. The first and second mating end faces are in contact. The cylindrical body and the end cap form a weld portion at the joint between the first outer side surface and the second outer side surface. The depth of the weld portion is defined as h, and the depth of the weld portion satisfies the following relationship: (d1-d2) < h < d1.

[0005] This application also provides a method for manufacturing a container, comprising the following steps:

[0006] Provide a cylindrical body and end caps;

[0007] The wall of the cylinder is thinned to form a first outer side, a second outer side, an inner side, and a first mating end face. The vertical distance from any position on the first outer side to the inner side is defined as d1; the vertical distance from any position on the second outer side to the inner side is defined as d2, where d2 < d1.

[0008] The end cap has a second mating end face and a bottom face, such that the first mating end face of the cylinder and the second mating end face of the end cap are in contact.

[0009] The cylinder and the end cap are joined at the first outer side facing the second outer side by laser welding to form a weld seam; the depth of the weld seam is defined as h, and the depth of the weld seam satisfies the following relationship: (d1-d2)<h<d1.

[0010] In the above technical solution, the wall includes a first outer side, a second outer side, and an inner side. The vertical distance from any position of the second outer side to the inner side is less than the vertical distance from any position of the first outer side to the inner side. The wall thickness of the cylinder is reduced. The wall has a first mating end face, which connects the first outer side and the second outer side. The end cap includes a second mating end face, which is mated with the first mating end face. The cylinder and the end cap are welded from the first outer side to the second outer side to form a weld. The cylinder is thinned at the second outer side wall. The part of the cylinder wall including the second outer side and the inner side can serve as a base plate during welding to prevent the molten weld from sinking. The weld penetration depth is reduced, and weld defects are reduced. Attached Figure Description

[0011] Figure 1 A welded structure consisting of a cylindrical body and end caps for a container;

[0012] Figure 2 This is the welded structure of the container body and end cap according to the first embodiment of the present invention;

[0013] Figure 3 This is the welding structure of the container body and end cap according to the second embodiment of the present invention;

[0014] Figure 4 This is a schematic diagram of the manufacturing steps of the container body and end cap according to the first embodiment of the present invention;

[0015] Figure 5 This is a schematic diagram of the manufacturing steps of the container body and end cap according to the second embodiment of the present invention;

[0016] Figure 6 This is a burst pressure diagram with a straight cut of 5mm according to the first embodiment of the present invention;

[0017] Figure 7 This is a burst pressure diagram of a 7.5mm straight cut according to the first embodiment of the present invention;

[0018] Figure 8 This is a burst pressure diagram with a 5mm oblique cut according to the first embodiment of the present invention;

[0019] Figure 9 This is a burst pressure diagram with a 7.5mm oblique cut according to the second embodiment of the present invention. Detailed Implementation

[0020] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0021] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a,” “the,” and “the” used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0022] It should be understood that the terms "first," "second," and similar terms used in this application specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, "a" or "one," and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one; "multiple" indicates two or more. Unless otherwise stated, terms such as "front," "rear," "lower," and / or "upper" are for illustrative purposes only and are not limited to a location or spatial orientation. Terms such as "comprising" or "including" indicate that the elements or objects preceding "comprising" encompass the elements or objects listed following "comprising" or "including" and their equivalents, but do not exclude other elements or objects.

[0023] The container of the exemplary embodiment of this application will be described in detail below with reference to the accompanying drawings. In this application, the container can be a liquid reservoir or a gas-liquid separator. Unless otherwise specified, the features of the following embodiments and implementations can complement or combine with each other.

[0024] See Figure 2The present invention provides a container 100 according to a first embodiment, including a cylindrical body 1 and an end cap 2, which are welded together. The cylindrical body 1 includes a wall portion 12, which includes a first outer side 121, a second outer side 122, and an inner side 123. The inner side 123 is closer to the center of the cylindrical body 1 than the first outer side 121 and the second outer side 122. The cylindrical body 1 has an inner cavity, which is formed by the inner side 123. The first outer side 121 and the second outer side 122 are not in direct contact with the inner cavity. The vertical distance from any position of the first outer side 121 to the inner side 123 of the cylindrical body 1 is defined as d1. The second outer side 123 is defined as... The vertical distance from any position 122 to the inner side 123 of the cylinder 1 is d2, where d2 < d1. In this invention, the first outer side 121 and the inner side 123 are arranged in parallel, the second outer side 122 and the inner side 123 are arranged in parallel, and the first outer side 121 and the second outer side 122 are arranged in parallel. Of course, any one of the first outer side 121 and the second outer side 122, the first outer side 121 and the inner side 123, and the second outer side 122 and the inner side 123 may not be limited to being arranged in parallel.

[0025] The wall portion 12 also includes a first mating end face 124, which connects the first outer side surface 121 and the second outer side surface 122. In this invention, the first mating end face 124 is perpendicular to the first outer side surface 121 and the first mating end face 124 is perpendicular to the second outer side surface 122. Here, the first mating end face and the first outer side surface are perpendicular. The perpendicularity can have a slight angle difference, but it needs to be kept as perpendicular as possible to facilitate welding.

[0026] In this embodiment, preferably, the vertical distance d1 from the first outer side 121 to the inner side 123 of the cylinder is 3.5 mm, the vertical distance d2 from the second outer side 122 to the inner side 123 of the cylinder is 1 mm, and the vertical distance between the first outer side 121 and the second outer side 122 is 2.5 mm. After welding the cylinder and end cap of this size, the number of pulse cracks is significantly increased compared to the existing cylinder and end cap, as shown in Table 1. In addition, the cylinder includes a protrusion, which includes the inner side 123 and the second outer side 122. The protrusion can partially serve as a base plate during laser welding to prevent the molten metal solder from sinking. Here, sinking refers to the phenomenon where the liquid metal that has been welded sinks under the action of gravity.

[0027] The end cap 2 includes a mating end 211, which has a second mating end face 213 and a bottom face 214. The bottom face 214 and the second outer side face 122 are arranged opposite to each other. This "opposite arrangement" means that the bottom face 214 and the second outer side face 122 are face-to-face; they can be parallel or non-parallel. The second outer side face 122 and the bottom face 214 are arranged opposite each other, and the verticality of the second outer side face can have a slight deviation, but it should be kept as perpendicular as possible to facilitate welding. The end cap also includes a third outer side face 212, which is perpendicular to the second mating end face 213. Of course, this perpendicular arrangement is not mandatory. In this embodiment, when the first mating end face 124 and the second mating end face 213 are mated, the cylinder 1 and the end cap 2 are welded together at the mating point from the first outer side face 121 to the second outer side face 122 to form a weld seam. The depth of the weld seam is defined as h, where (d1-d2) < h < d1. At this time, the first outer side face 121 and the third outer side face 212 are on the same plane.

[0028] The mating end 211 of the end cap 2 is provided with a groove 215, the groove 215 having a groove 216, the inner side 123 and the second outer side 122 protruding portions being at least partially located within the groove 216, with a cutting depth of 7.5 mm. In this invention, the protruding portions extend into the groove, the groove 215 having a first groove wall 2151 and a second groove wall 2152, the first groove wall 2151 and the second groove wall 2152 being planar, the groove 215 being a semi-circular groove, the groove 216 of the groove 215 serving as a cutting groove, the first groove wall 2151 serving as the bottom surface 214 of the mating end, the first groove wall 2151 being disposed opposite to the second outer side 122, the second groove wall having a gap with the inner side 123, the first groove wall 2151 and the second outer side 122 being either abutting or not abutting. In this embodiment, the tensile stress in the weld is transformed into compressive stress, which reduces fatigue loss. In this embodiment, the tensile part of the container structure is located at the end cap, and the tensile length is relatively short. The cumulative deformation in the weld is small, and the weld is less prone to cracking.

[0029] In this embodiment, the cylinder body is approximately cylindrical, and the end cap is also approximately cylindrical. The cylinder body and end cap are fixed together by laser welding. Other welding methods can also be used, such as argon arc welding, electromagnetic pulse cold pressure welding, MIG welding, etc.

[0030] Table 1 First Embodiment and Figure 1 Case Pulse Test Comparison Table

[0031]

[0032] Note: In Table 1, #1 represents the position of the weld start point, #4 represents the position of the weld end point, #2 and #3 represent two positions located between #1 and #4, and #1, #2, #3 and #4 are evenly distributed.

[0033] Table 1 shows the pulse and pulse of the first embodiment. Figure 1 The scheme comparison test table shows that, as can be seen from Table 1, the first embodiment is superior to... Figure 1 The number of crack pulses generated at each weld location in the scheme has increased.

[0034] Table 2 Comparison of Explosion Tests at Different Cutting Depths of Groove in the First Embodiment

[0035]

[0036] Table 2 is a comparison table of blasting tests at different penetration depths in the first embodiment. Figure 6 The burst pressure curve is calculated under the following conditions: a first-stage pressure holding time of 60 seconds, a first-stage velocity of 60, a first-stage pressure of 13 MPa, a second-stage pressure holding time of 60 seconds, a second-stage velocity of 6, and a second-stage pressure of 26 MPa. Figure 7 The curve of burst pressure is given under the following conditions: a straight cut of 7.5mm, a first-stage holding time of 60s, a first-stage speed of 60, a first-stage pressure of 13MPa, a second-stage holding time of 60s, a second-stage speed of 6, and a second-stage pressure of 26MPa.

[0037] Combined with Table 1 and Figure 6 , Figure 7 It can be seen that for a straight cut of 5mm, the burst rate is 6, the burst pressure is 40MP, and the peak pressure is 29.851MP. For a straight cut of 7mm, the burst rate is 6, the burst pressure is 40MP, and the peak pressure is 30.866MP.

[0038] See Figure 3 The container 100' of the second embodiment of the present invention includes a cylindrical body 1' and an end cap 2'. The cylindrical body 1' includes a wall portion 12', which includes a first outer side 121', a second outer side 122', and an inner side 123'. The inner side 123' is closer to the centerline of the cylindrical body 1' than the first outer side 121' and the second outer side 122'. The vertical distance from any position of the first outer side 121' to the inner side 123' of the cylindrical body 1' is defined as d1, and the vertical distance from any position of the second outer side 122' to the inner side 123' of the cylindrical body 1' is defined as d2, where d2 < d1. In this embodiment, the first outer side 121' and the inner side 123' are arranged in parallel, while the second outer side 122' and the inner side 123' are not arranged in parallel.

[0039] The wall portion 12' has a first mating end face 124', which connects the first outer side surface 121' and the second outer side surface 122'. In this embodiment, the first mating end face 124' is perpendicular to the first outer side surface 121' and not perpendicular to the second outer side surface 122'. The second outer side surface 122' and the first mating end face 124' form an angle α, where 90° ≤ α < 180°. Furthermore, the vertical distance from the line connecting the first mating end face 124' and the second outer side surface 122' to the inner side surface is defined as m. Preferably, the vertical distance d1 from the first outer side surface to the inner side surface of the cylinder is 3.5 mm, the vertical distance d2 from the second outer side surface to the inner side surface of the cylinder is 1 mm, the vertical distance m from the line connecting the first mating end face and the second outer side surface to the inner side surface is 2.3 mm, and the angle α = 100° between the second outer side surface 122' and the first mating end face 124' results in a low fatigue pulse count after the cylinder and end cap of this size are welded together. In addition, the protrusions on the inner and second outer surfaces can partially serve as a base plate during laser welding, preventing the molten metal solder from sinking.

[0040] The end cap 2' includes a mating end 211', and has a third outer surface 212', a second mating end surface 213', and a bottom surface 214'. The bottom surface 214' and the second outer surface 212' are arranged opposite each other, meaning they are face-to-face. The included angle β between the bottom surface 214' and the second outer surface 212' is β = 260°. The second outer surface 122' and the bottom surface 214' are perpendicular, although there can be slight deviations, they should be kept as perpendicular as possible to facilitate welding. The third outer surface 212' and the second mating end surface 213' are also perpendicular, although this is not always necessary. In this invention, when the first mating end surface 124' and the second mating end surface 213' are mated, the cylinder 1' and the end cap 2' are welded together at the mating point from the first outer surface 121' to the second outer surface 122' to form a weld seam. At this time, the first outer surface 121' and the third outer surface 212' are on the same horizontal plane.

[0041] The mating end 211' of the end cap 21' is provided with a groove 215', the groove 215' has a groove 216', the inner side 123' and the second outer side 122' protruding portions are at least partially located in the groove 216'. In this invention, the protruding portions extend into the groove. The groove 215' has a first groove wall 2151' and a second groove wall 2152'. The groove 216' of the groove 215' can serve as a tool inlet groove. The first groove wall 2151' serves as the bottom surface 214' of the mating end. The first groove wall 2151' and the second outer side 122' are arranged opposite to each other and can abut against each other. The angle between the extension line of the first groove wall 2151' and the extension line of the second groove wall 2152' is δ, where δ = 20°.

[0042] In this embodiment, the cylinder body is approximately cylindrical, and the end cap is also approximately cylindrical. The cylinder body and the cylindrical end cap are fixed together by laser welding. Other welding methods can also be used, such as argon arc welding, electromagnetic pulse cold pressure welding, MIG welding, etc.

[0043] Since the tensioned part of the container structure in this embodiment is located at the end cap, the tension length is relatively short, the cumulative deformation at the weld is small, the weld is less prone to cracking, and the end cap side becomes thicker as it is tilted inwards, thus increasing reliability.

[0044] Table 3 Comparison of pulse test results between the second embodiment and existing solutions.

[0045]

[0046] Note: In Table 3, #1 represents the position of the weld start point, #4 represents the position of the weld end point, #2 and #3 represent two positions located between #1 and #4, and #1, #2, #3 and #4 are evenly distributed.

[0047] Table 3 is a test table comparing the pulse of the second embodiment with the existing solution. As can be seen from Table 3, the number of crack-generating pulses at the four weld positions in the first embodiment is increased compared with the existing solution, indicating that the angled groove has enhanced tensile crack resistance compared with the non-grooved solution in the existing solution, and the weld is less prone to tensile cracking.

[0048] Combining Tables 1 and 3, it can be seen from Table 3 that the number of crack pulses generated at the four weld positions in the first embodiment is increased compared with that in the second embodiment, indicating that the right-angled groove has better tensile strength than the oblique-angled groove, and the weld is less prone to tensile cracking.

[0049] Table 4. Comparison of blasting tests at different groove depths in the second embodiment. (Blasting test table)

[0050]

[0051] Table 4 is a comparison table of blasting tests at different penetration depths in the second embodiment. Figure 8 The curve of burst pressure is obtained under the following conditions: a 5mm bevel cut, a first-stage pressure holding time of 60s, a first-stage velocity of 60, a first-stage pressure of 13MPa, a second-stage pressure holding time of 60s, a second-stage velocity of 6, and a second-stage pressure of 26MPa. Figure 9 The curve of burst pressure is given under the following conditions: a 7.5mm bevel cut, a first-stage pressure holding time of 60s, a first-stage speed of 60, a first-stage pressure of 13MPa, a second-stage pressure holding time of 60s, a second-stage speed of 6, and a second-stage pressure of 26MPa.

[0052] Combined with Table 4 and Figure 8 , Figure 9It can be seen that for a straight cut of 5mm, the burst rate is 6, the burst pressure is 40MP, and the peak pressure is 30.86MP. For a straight cut of 7.5mm, the burst rate is 6, the burst pressure is 40MP, and the peak pressure is 30.12MP.

[0053] See Figure 2 and Figure 4 The present invention provides a method for manufacturing a container 100 according to a first embodiment, the method comprising the following steps:

[0054] Provide a cylinder 1 and an end cap 2.

[0055] The wall portion 12 of the cylinder is thinned to form a first outer surface 121, a second outer surface 122, and a first mating end surface 124.

[0056] End cap 2 has a second mating end face 213 and a bottom face 214, such that the first mating end face of cylinder 1 and the second mating end face 213 of end cap 124 are mated.

[0057] The cylinder 1 and the end cap 2 are laser welded together at the joint from the first outer side 121 to the second outer side 122.

[0058] The end cap 2 is grooved, and the protruding portions of the second outer side 122 and the inner side 123 are at least partially located in the groove 216. The groove portion 215 has a first groove wall 2151 and a second groove wall 2152, and the groove depth is 7.5 mm.

[0059] Here, the cylinder 1 and the end cap 2 are laser welded together. At the joint between the cylinder 1 and the end cap 2, a weld joint is formed by welding from the first outer side 121 to the second outer side 122. The depth of the weld joint is defined as h. The vertical distance d1 from the first outer side to the inner wall of the cylinder is 3.5 mm, the vertical distance d1 from the second outer side to the inner wall of the cylinder is 1 mm, the distance between the first outer side and the second outer side is 2.5 mm, and the welding depth h is 2.7 mm.

[0060] See Figure 3 and Figure 5 The present invention provides a method for manufacturing a container 100' according to a second embodiment, the method comprising the following steps:

[0061] A cylindrical body 1' and an end cap 2' are provided;

[0062] The wall portion 12' of the cylinder 1' is thinned to form a first outer surface 121', a second outer surface 122', and a first mating end face 124'. The second outer surface 122' and the first mating end face 124' form an included angle α, where 90°≤α<180° and α=110°.

[0063] The end cap 2' is grooved, with at least a portion of the second outer side and inner side located within the groove. The groove portion 215' has a first groove wall 2151' and a second groove wall 2152'. The groove depth is preferably 7.5 mm. The mating end 211' of the end cap 2' is provided with a groove portion 215', which has a groove 216'. The protruding portions of the inner side 123' and the second outer side 122' are at least partially located within the groove 216'. The groove 216' of the groove portion 215' can serve as a feed groove. The first groove wall 2151' serves as the bottom surface 214' of the mating end. The first groove wall 2151' is arranged opposite to the second outer side 122' and can abut against it. The angle between the extension line of the first groove wall 2151' and the extension line of the second groove wall 2152' is δ, where δ = 20°.

[0064] The end cap 2' has a second mating end face 213' and a bottom face 214', such that the first mating end face 124' of the cylinder 1' and the second mating end face 213' of the end cap 2' are mated, and the included angle β between the bottom face 214' and the second outer side face 122' is β = 250°.

[0065] Here, the cylinder 1' and end cap 2' are laser welded together. At the joint between the cylinder 1' and end cap 2', a weld joint is formed from the first outer side 121' to the second outer side 122'. The depth of the weld joint is defined as h. The thickness of the vertical distance d1 from the first outer side to the inner side of the cylinder is 3.5 mm, and the welding depth h is 2.7 mm.

[0066] The above description is merely a preferred embodiment of this application and is not intended to limit this application in any way. Although this application has disclosed the preferred embodiment as above, it is not intended to limit this application. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the technical solution of this application. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of this application without departing from the content of the technical solution of this application shall still fall within the scope of the technical solution of this application.

Claims

1. A container comprising a cylindrical body and an end cap, the cylindrical body including a wall portion, characterized in that, The wall portion includes a first outer side, a second outer side, and an inner side. The cylinder has an inner cavity, and the inner side surrounds and forms a portion of the inner cavity. The first and second outer sides are not in direct contact with the inner cavity. The inner side is closer to the central axis of the inner cavity than the first and second outer sides. The vertical distance from any position of the first outer side to the inner side is defined as d1; the vertical distance from any position of the second outer side to the inner side is defined as d2, where d2 < d1. The wall portion also includes a first mating end face, which connects the first outer side and the second outer side. The end cap includes a mating end, which has a second mating end face and a bottom surface. The bottom surface is disposed opposite to the second outer side. The first mating end face and the second mating end face are mated. The cylinder and the end cap are welded from the first outer side to the second outer side to form a weld portion. The depth of the weld portion is defined as h, and the depth of the weld portion satisfies the following relationship: (d1-d2) < h < d1.

2. The container as described in claim 1, characterized in that, The mating end includes a groove, the groove having a groove, portions of the second outer side and the inner side being located within the groove, the groove having a first groove wall and a second groove wall, the first groove wall being the bottom surface of the mating end, the first groove wall being disposed opposite to the second outer side, and the second groove wall having a gap with the inner side.

3. The container as described in claim 2, characterized in that, The container cross-section is formed at the docking point. From the cross-section, the second outer side surface and the first docking end surface form a first included angle α, 90°≤α<180°. The first outer side surface is parallel to the inner side surface. The first tank wall or its extension surface and the second tank wall or its extension surface form a second included angle δ, 0°<δ<90°.

4. The container as described in claim 2, characterized in that, The first outer side is parallel to the second outer side, and the first outer side is parallel to the inner side. The end cap includes a third outer side, which is parallel to the first groove wall. The first outer side is perpendicular to the first mating end face, and the second mating end face is perpendicular to the first groove wall. The first groove wall and the second groove wall are parallel. The first outer side and the third outer side are on the same plane.

5. The container as described in claim 4, characterized in that, The bottom of the groove is a circular groove structure. The bottom of the groove is smoothly connected to the first groove wall and the second groove wall. The distance between the first groove wall and the second groove wall is greater than twice the vertical distance from any position of the second outer side to the inner side.

6. The container as described in any one of claims 3-5, characterized in that, The distance between the first mating end face and the end of the cylinder is less than the maximum distance between the second mating end face and the bottom of the groove.

7. The container as claimed in claim 6, characterized in that, The cylinder body is cylindrical, the end cap is cylindrical, and the weld seam is annular.

8. A method for manufacturing a container, capable of manufacturing the container according to any one of claims 1 to 7, characterized in that, Includes the following steps: Provide a cylindrical body and end caps; The wall of the cylinder is thinned to form a first outer side, a second outer side, an inner side, and a first mating end face. The vertical distance from any position on the first outer side to the inner side is defined as d1; the vertical distance from any position on the second outer side to the inner side is defined as d2, where d2 < d1. The end cap includes a mating end portion, the mating end portion including a groove portion having a groove, and the end cap having a second mating end face and a bottom surface, such that the first mating end face of the cylinder and the second mating end face of the end cap are in contact. The cylinder and the end cap are joined at the first outer side facing the second outer side by laser welding to form a weld seam; the depth of the weld seam is defined as h, and the depth of the weld seam satisfies the following relationship: (d1-d2)<h<d1.

9. The manufacturing method as described in claim 8, characterized in that, In the end cap groove treatment, the second outer side and inner side are at least partially located in the groove. The groove has a first groove wall and a second groove wall. The first groove wall is the bottom surface of the mating end. The first groove wall is disposed opposite to the second outer side. There is a gap between the second groove wall and the inner side.

10. The manufacturing method as described in claim 9, characterized in that, The bottom of the groove is a circular groove structure. The bottom of the groove is smoothly connected to the first groove wall and the second groove wall. The minimum distance between the first groove wall and the second groove wall is greater than twice the vertical distance from any position of the second outer side to the inner side.

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