Winding gas cylinder and preparation method thereof

Abstract

The invention discloses a winding gas cylinder and a preparation method thereof. The winding gas cylinder comprises a gas cylinder liner, a fiber winding layer and a toughening buffer layer, the fiber winding layer comprises annular winding layers and spiral winding layers which are alternately arranged; the annular winding layer is arranged on the cylinder body section of the gas cylinder liner; the spiral winding layer is arranged on the whole length section of the gas cylinder liner; the toughening buffer layer comprises an interlayer toughening buffer layer, and the interlayer toughening buffer layer is arranged at the position, between the annular winding layer and the spiral winding layer, of the cylinder body section. By arranging the toughening buffer layer, on one hand, more resin is locked by the fabric felt, the thickness of an adhesive layer between the annular winding layer and the spiral winding layer is effectively guaranteed, and therefore the interlayer bonding strength is improved; on the other hand, the toughening buffer layer is arranged, the influence of low interlayer shear strength caused by winding angle difference between the annular winding layer and the spiral winding layer is reduced, the interlayer bonding strength is improved, and therefore the compression strength of the gas cylinder is improved.

Description

Technical Field

[0001] The invention relates to a winding molding process, and in particular to a winding gas cylinder and a preparation method thereof. Background Art

[0002] Compared with traditional metal gas cylinders, composite wrapped gas cylinders are receiving more and more attention due to their advantages such as light weight and high specific strength, especially in the field of transportation. Wrapped gas cylinders are composite products formed by continuous fibers impregnated with resin, followed by the designed process laying rules, and then wound onto the inner liner core mold, and heated and cured. In order to ensure the overall pressure resistance of the gas cylinder during product design, the winding process usually adopts alternating winding of small-angle spiral winding layers and large-angle circumferential winding layers. The circumferential winding layer mainly strengthens the barrel section, and the small-angle spiral winding mainly strengthens the ends of the gas cylinder. A transition layer needs to be inserted between the circumferential winding layer and the spiral winding layer to achieve continuous and stable changes in the position and angle of the winding head.

[0003] According to the winding rules, the radial pressure of the fibers of the small-angle spiral winding layer in the barrel section is much smaller than that of the circumferential winding layer, resulting in the fiber arrangement of the small-angle spiral layer in the barrel section not being dense enough. Even if the circumferential winding layer is used to compress it in time, it is easy to form holes in the interlayers of the alternating layers due to residual bubbles. Moreover, because the circumferential winding layer squeezes out excess resin, the thickness of the glue between the alternating layers becomes thinner, which also reduces the bonding strength between the winding layers, resulting in low fiber strength performance in the barrel section, and easy to explode and fail in the barrel section. In addition, the winding of the barrel section is composed of alternating circumferential winding layers and spiral winding layers. The winding angles of different winding layers will change, especially when the winding angle of the spiral winding layer is less than 55°, which is significantly different from the winding angle of the circumferential winding layer close to 90°, resulting in low bonding strength between the winding layers, which is easy to cause interlayer shear failure during the pressure test, resulting in failure of the gas cylinder. Although some patents point out that the winding adhesive can be toughened and modified to improve the interlayer strength of the gas cylinder, the use of modified adhesive to wrap the gas cylinder usually affects the processability of the winding adhesive and the cost increases significantly, which is not conducive to mass application.

[0004] After winding, the tension of the impregnated fiber needs to be released and cut off. The impregnated fiber is manually knotted or the tail yarn is fixed to the product surface by circumferential winding with high-temperature tape. When the fiber winding tension is released, the tension of the outer fiber of the winding layer is easily reduced, affecting the uniformity of the mechanical properties of the product; the fiber surface after dipping is smooth and the friction is small. The quality of manually knotted fibers or fixed fibers by tape winding is unstable. There is a risk of loose fibers during the curing process, which affects the linear fixation of the outer fiber, causing the outer fiber to slip or even reverse unwinding, resulting in the scrapping of the wound product; manual knotting after releasing the tension causes the joint to be narrower and thicker than during normal winding, and the joint remains on the product surface, affecting the appearance of the product. At the same time, it is easy to form stress concentration points and reduce product quality.

[0005] In addition, if the inner liner is made of metal, in order to prevent galvanic corrosion between the aluminum alloy and the carbon fiber winding layer, glue will be applied to the surface of the metal inner liner before the carbon fiber layer is wound. However, since the glue is incompatible with the aluminum alloy material, it is difficult to evenly apply the glue to the surface of the aluminum alloy inner liner, and there is a risk of partial glue shortage, which may cause electrochemical corrosion between the aluminum alloy and the carbon fiber, causing the gas cylinder to be scrapped. Summary of the invention

[0006] In view of this, the present invention provides a wrapped gas cylinder and a preparation method to solve the problems of low shear strength between winding layers caused by differences in winding angles, thin glue layer thickness, residual bubbles between layers, etc. that occur in the winding process of the prior art, as well as quality defects caused when the tail yarn is fixed at the end of winding.

[0007] In a first aspect, a wound gas cylinder is provided, comprising a gas cylinder liner, a fiber winding layer, and a toughening buffer layer; the fiber winding layer comprises an alternating circumferential winding layer and a spiral winding layer; the circumferential winding layer is arranged within the barrel section of the gas cylinder liner; the spiral winding layer is arranged within the entire length section of the gas cylinder liner; the toughening buffer layer comprises an interlayer toughening buffer layer, and the interlayer toughening buffer layer is arranged within the barrel section between the circumferential winding layer and the spiral winding layer.

[0008] In another embodiment, the innermost layer and the outermost layer of the fiber-wound layer are hoop-wound layers.

[0009] In another embodiment, the wrapped gas cylinder further comprises a toughening buffer layer on the surface of the inner liner, and the toughening buffer layer on the surface of the inner liner is arranged on the entire surface of the inner liner of the gas cylinder.

[0010] In another embodiment, the liner surface toughening buffer layer includes an liner surface toughening buffer layer barrel section and end caps at both ends.

[0011] In another embodiment, the fiber winding layer includes fibers and a resin matrix; the fibers can be in the form of continuous fibers or yarns; the toughened buffer layer is composed of a fabric felt and a resin matrix, and the fabric felt is any one of glass fiber felt, carbon felt, and polyester felt; the resin matrix includes at least any one of polyurethane, modified epoxy resin, and acrylate.

[0012] In another embodiment, the gas cylinder liner is a metal liner, and the fabric felt of the toughened buffer layer on the surface of the liner is any one of glass fiber felt and polyester felt.

[0013] In a second aspect, the present invention provides a method for preparing the above-mentioned wrapped gas cylinder, comprising the steps of: The fiber winding layer and the interlayer toughening buffer layer are wound on the gas cylinder liner through a winding production line, specifically including: the fibers impregnated with the first resin matrix are alternately wound on the gas cylinder liner in a circumferential winding layer and a spiral winding layer according to the layer design, and during the winding of the transition layer from the circumferential winding layer to the spiral winding layer, or during the winding of the transition layer from the spiral winding layer to the circumferential winding layer, the fabric felt of the interlayer toughening buffer layer is wound simultaneously, and N turns are wound, N is an integer greater than or equal to 1, and then the fabric felt is cut off before the winding of the transition layer is completed, and the fabric felt winding is stopped; and in the process of winding the fabric felt, a sufficient amount of the second resin matrix needs to be sprayed on the fabric felt at the same time to soak the fabric felt. In the process of winding the transition layer and the interlayer toughening buffer layer, when the fabric felt of the interlayer toughening buffer layer is wound for multiple turns, the fabric felt and the transition layer fibers will overlap each other, but because the distribution of the transition layer fibers is very sparse, the fibers of the transition layer are ignored, and the whole layer is still regarded as the interlayer toughening buffer layer.

[0014] In another embodiment, before winding the fiber winding layer on the gas cylinder liner, it is also necessary to first set a liner surface toughening buffer layer on the outer surface of the gas cylinder liner, which specifically includes the steps of: placing the fabric felt in a head forming mold, and compression molding a head preform; then setting the preformed head preform at the corresponding position of the gas cylinder liner, and tightly winding the fabric felt around the cylinder liner barrel, and docking the two sides of the fabric felt with the head preform; at the same time, during the winding process of the fabric felt, spraying a sufficient amount of the second resin matrix on the fabric felt to penetrate the fabric felt, thereby forming the liner surface toughening buffer layer after subsequent curing.

[0015] In another embodiment, when the inner liner of the gas cylinder is a metal liner, the fabric felt should be glass fiber felt or polyester felt.

[0016] In another embodiment, the first resin matrix and the second resin matrix are different in system, and the two different resin matrices form an interpenetrating structure after co-curing reaction.

[0017] In another embodiment, the method for preparing a wrapped gas cylinder further includes fixing the tail yarn, specifically comprising: Step 1: According to the fiber winding layer design, determine the end position of the fiber of the last fiber winding layer wound around the gas cylinder, so that the fiber after the end position stops infiltrating the resin matrix; Step 2: When the fiber winding of the last fiber winding layer of the wound gas cylinder is completed, the release cloth is wound on the wound gas cylinder from the fiber end position, and the fiber that is not impregnated with the resin matrix is ​​continued to be wound while maintaining the winding tension of the wound gas cylinder, so as to form a circumferential dry fiber layer and a release cloth layer with a set width and overlapped and wound on the surface of the wound gas cylinder; Step 3: After the fibers not soaked in the resin matrix and the release cloth are overlapped and wound for 1-2 turns, the winding tension is released, the fibers are cut, and the release cloth is continued to be overlapped for at least half a turn, and then the release cloth is cut and the end of the release cloth is fixed with high-temperature tape; Step 4: transport the wrapped gas cylinder as a whole to an oven for heating and curing; Step 5: After cooling, remove the high-temperature tape, the demoulding cloth layer, and the circumferential dry fiber layer to obtain a wound gas cylinder with no fiber joints on the surface and with a stable tension.

[0018] In another embodiment, the step three further comprises spraying a plurality of sections of quick-drying glue in a circumferential direction on the circumferential dry fiber layer or the release cloth layer, and locally heating the quick-drying glue to fix the release cloth layer.

[0019] In another embodiment, the winding production line includes a hoop winding tool for laying winding fabric felt and release cloth.

[0020] In another embodiment, the circumferential winding tooling includes a mounting plate, a reeling roller, a glue groove, a slitting roller, and a pressure roller. There are two mounting plates, which are arranged opposite to each other and are used to install and fix the reeling roller, the glue groove, the slitting roller, and the pressure roller; the reeling roller is arranged parallel to the axis of the gas cylinder inner liner, and its two ends are respectively connected to two mounting plates; the glue groove is arranged parallel to the axis of the gas cylinder inner liner in the length direction, and its two ends are connected to the mounting plate through the first connecting arm; the slitting roller is arranged parallel to the axis of the gas cylinder inner liner, and its two ends are connected to the mounting plate through the second connecting arm; the pressure roller is connected to the mounting plate through the third connecting arm.

[0021] Working principle: (1) For fabric felt winding: install the fabric felt reel onto the unwinding roller shaft, adjust it to be parallel to the cylinder barrel section, pull out the fabric felt head, pass it through the guide roller, insert it into the gap between the cutting rollers, and continue to pull it down to the clamping roller. Use the clamping roller to tightly wrap the fabric felt around the cylinder and start winding the fabric felt. When the fabric felt winding is completed, cut it with the slitting roller. For the fabric felt wound around the toughened buffer layer on the surface of the liner, its head end can be fixed by an auxiliary tape; for the fabric felt wound around the toughened buffer layer between layers, since the fibers have a resin matrix, its head end can be effectively attached and fixed to the fiber layer wound around the cylinder; (2) Used for stripping cloth winding: remove the fabric felt reel and replace it with a stripping cloth reel, which can be used for stripping cloth winding when the tail yarn is fixed.

[0022] The wrapped gas cylinder of the present invention introduces a toughening buffer layer between the circumferential winding layer and the spiral winding layer. Since the toughening buffer layer is composed of fabric felt and resin, the fabric felt can lock more resin matrix, effectively ensuring the thickness of the adhesive layer, effectively improving the interlaminar strength of the composite winding layer, and improving the compressive strength of the gas cylinder; in addition, the toughening buffer layer is provided to reduce the effect of low interlaminar shear strength caused by the difference in winding angles between the circumferential winding layer and the spiral winding layer, improve the interlaminar bonding strength, and thus improve the compressive strength of the wrapped gas cylinder. By providing a toughening buffer layer on the surface of the liner, on the one hand, the toughness of the gas cylinder can be improved, and on the other hand, when the liner of the gas cylinder is an aluminum alloy liner, a uniform anti-electrochemical corrosion layer can be effectively formed on the surface of the aluminum alloy liner, thereby avoiding failure of the gas cylinder caused by galvanic corrosion between the aluminum alloy liner and the carbon fiber.

[0023] In addition, the first resin matrix used to impregnate the fibers and the second resin matrix used to impregnate the fabric felt are resin matrices of different systems. After the two resin matrices of different systems are blended and cured, an interpenetrating network structure is formed to achieve blending and toughening of resins between different winding layers, thereby improving the strength between winding layers of the wound gas cylinder and enhancing the toughness of the gas cylinder.

[0024] The use of the hoop winding tool in the present invention can achieve tight winding of the fabric felt on the fiber layer, discharge excess bubbles and resin matrix, improve product density, and improve the interlayer strength and toughness of the wound gas cylinder.

[0025] The tail yarn fixing method of the present invention adopts the method of fixing the dry fiber and the demoulding cloth after overlapping each other while maintaining the winding tension, thus avoiding the need to release the fiber winding tension in advance and the problem that the surface of the adhesive-carrying fiber is smooth and difficult to tie a knot, thereby maintaining the consistent winding tension of the fiber wound product; improving the quality of the tail yarn fixing, avoiding the knotted joint remaining on the product surface, and effectively improving the appearance and quality of the product; using the demoulding cloth and the fiber to overlap each other, and the quick-drying glue to bond the dry fiber and the demoulding cloth has high operability and good repeatability, and can effectively improve the process stability of the winding molding. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Attached Figure 1 It is a schematic diagram of the axial section structure of the gas cylinder; Attached Figure 2 It is a schematic diagram of the circumferential cross-sectional structure of the gas cylinder; Attached Figure 3 It is a schematic diagram of the structure of the buffer layer on the surface of the inner tank; Attached Figure 4 It is the axial cross-section diagram when the tail yarn is fixed; Attached Figure 5 It is the annular cross-section diagram when the tail yarn is fixed; Attached Figure 6 It is a schematic diagram of the hoop winding tooling structure; Attached Figure 7 It is a schematic diagram of the coordination between the hoop winding tooling and the winding head; Among them: 1-cylinder liner; 2-fiber winding layer; 21-circumferential winding layer; 22-spiral winding layer; 3-toughened buffer layer; 31-interlayer toughened buffer layer; 32-liner surface toughened buffer layer; 321-liner surface toughened buffer layer barrel section; 322-head; 4-mold release cloth layer; 5-circumferential dry fiber layer; 6-high temperature resistant tape; 7-quick-drying glue; 8-circumferential winding tooling; 81-mounting plate; 82-unwinding roller; 83-glue groove; 84-slitting roller; 85-pressing roller; 86-first connecting arm; 87-second connecting arm; 88-third connecting arm; 9-fiber; 10-fabric felt. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0028] It should be noted that in the description of the present invention, the terms "center", "upper", "lower", "inner", "outer", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0029] As attached Figure 1-2The figure shows a wound gas cylinder, including a gas cylinder liner 1, a fiber winding layer 2, and a toughening buffer layer 3; the fiber winding layer 2 includes an alternating circumferential winding layers 21 and a spiral winding layer 22; the innermost layer and the outermost layer of the fiber winding layer 2 are the circumferential winding layers 21; the circumferential winding layers 21 are arranged in the barrel section of the gas cylinder liner 1; the spiral winding layer 22 is arranged in the entire length section of the gas cylinder liner 1; the toughening buffer layer 3 includes an interlayer toughening buffer layer 31, and the interlayer toughening buffer layer 31 is arranged in the barrel section between the circumferential winding layer 21 and the spiral winding layer 22.

[0030] The fiber winding layer 2 includes fibers and a resin matrix; the fibers can be in the form of continuous fibers or yarns; the interlayer toughening buffer layer 31 includes a fabric felt and a resin matrix, and the fabric felt is any one of glass fiber felt, carbon felt, and polyester felt; the resin matrix includes at least any one of polyurethane, modified epoxy resin, and acrylate.

[0031] The wrapped gas cylinder further comprises a liner surface toughening buffer layer 32 , which is arranged between the surface of the gas cylinder liner 1 and the innermost circumferential wrapping layer 21 and is arranged within the entire length of the gas cylinder liner 1 .

[0032] The toughened buffer layer 32 on the surface of the liner includes a fabric felt and a resin matrix. The fabric felt is any one of glass fiber felt and polyester felt. The resin matrix includes at least any one of polyurethane, modified epoxy resin and acrylate.

[0033] As attached Figure 3 As shown, the inner liner surface toughening buffer layer 32 includes an inner liner surface toughening buffer layer barrel section 321 and end caps 322 at both ends.

[0034] See attached Figure 3-7 The method for preparing the wrapped gas cylinder comprises: The fiber winding layer 2 and the interlayer toughening buffer layer 31 are wound on the gas cylinder liner 1 through a winding production line, specifically comprising: the fiber 9 impregnated with the first resin matrix is ​​alternately wound around the circumferential winding layer 21 and the spiral winding layer 22 on the gas cylinder liner 1 according to the layer design; during the winding of the transition layer from the circumferential winding layer 21 to the spiral winding layer 22, or during the winding of the transition layer from the spiral winding layer 22 to the circumferential winding layer 21, the fabric felt 10 of the interlayer toughening buffer layer 31 is simultaneously wound N times, where N is an integer greater than or equal to 1; then the fabric felt 10 is cut off before the winding of the transition layer is completed, and the winding of the fabric felt 10 is stopped; and, during the winding process of the fabric felt 10, a sufficient amount of the second resin matrix needs to be sprayed on the fabric felt 10 to penetrate the fabric felt 10.

[0035] Before winding the fiber winding layer 2 on the gas cylinder liner 1, it is also necessary to first set a liner surface toughening buffer layer 32 on the outer surface of the gas cylinder liner 1, specifically including: placing the fabric felt in a head 322 molding mold, and compression molding the head 322; then setting the preformed head 322 at the corresponding position of the gas cylinder liner 1, and tightly winding the fabric felt 10 around the barrel of the gas cylinder liner 1, and the two sides of the fabric felt 10 are connected to the head; in addition, when winding the fabric felt 10, the fabric felt 10 must be simultaneously impregnated with a second resin matrix, thereby forming the liner surface toughening buffer layer 32.

[0036] When the gas cylinder liner 1 is a metal liner, the fabric felt 10 of the toughening buffer layer 32 on the surface of the liner should be glass fiber fabric felt or polyester fabric felt.

[0037] The first resin matrix used for impregnating the fiber 9 can usually be selected from epoxy resin or modified epoxy resin, and the second resin matrix used for impregnating the fabric felt 10 is a toughening resin, which can be any one of polyurethane, modified epoxy resin, and acrylate; and the first resin matrix used for impregnating the fiber 9 and the second resin matrix used for impregnating the fabric felt 10 should be resins of different systems, and the two different systems of resins form an interpenetrating structure after co-curing reaction.

[0038] See attached Figure 4-5 As shown, the preparation method of the wrapped gas cylinder also includes tail yarn fixing, specifically including: Step 1: According to the winding design, determine the end position of the fibers of the last fiber winding layer 2 of the gas cylinder, so that the fibers after the end position stop infiltrating the resin matrix; Step 2: When the fiber winding of the last fiber winding layer 2 of the wound gas cylinder is completed, start winding the release cloth on the wound gas cylinder from the end position of the fiber, and keep the winding tension of the wound gas cylinder to continue winding the fiber 9 that is not impregnated with the resin matrix, so that the fiber 9 that is not impregnated with the resin matrix and the release cloth are overlapped and intertwined with each other, and form a circumferential dry fiber layer 5 and a release cloth layer 4 of a set width and overlapped and intertwined with each other on the surface of the wound gas cylinder; the width of the circumferential dry fiber layer 5 is controlled to be 1-2 times the yarn width; the width of the release cloth layer 4 is greater than the width of the circumferential dry fiber layer 5, preferably 2-4 times the yarn width; the yarn width refers to the width of the continuous fiber or yarn used in the fiber winding layer; Step 3: After the fibers not soaked in the resin matrix and the release cloth are overlapped and wound for 1-2 turns, the winding tension is released, the fibers 9 are cut, and the release cloth is wound for another turn, and then the release cloth is cut and the end of the release cloth is fixed with a high temperature resistant tape 6; Step 4: transport the wrapped gas cylinder as a whole to an oven for heating and curing; Step 5: After cooling, the high temperature resistant tape 6, the demoulding cloth layer 4, and the circumferential dry fiber layer 5 are removed to obtain a wound gas cylinder with no fiber joints on the surface and with a constant tension.

[0039] Furthermore, the step three also includes spraying several sections of quick-drying glue 7 on the outermost circumferential dry fiber layer 5 or the release cloth layer 4 in the circumferential direction, and locally heating the quick-drying glue 7 to fix the release cloth layer 4.

[0040] See attached Figure 6-7 As shown, the winding production line includes a circumferential winding tool 8 for laying winding fabric felt and demoulding cloth. The circumferential winding tool 8 includes a mounting plate 81, an unwinding roller shaft 82, a glue groove 83, a slitting roller 84, and a pressing roller 85. The mounting plates 81 have two pieces, which are arranged opposite to each other; the unwinding roller shaft 82 is used to place the fabric felt roll, and its two ends are respectively connected to the two mounting plates 81; the glue groove 83 is used to load the second resin matrix, and is connected and fixed to the mounting plate 81 through a first connecting arm 86; the slitting roller 84 is connected and fixed to the mounting plate 81 through a second connecting arm 87; and the pressing roller 85 is connected and fixed to the mounting plate 81 through a third connecting arm 88.

[0041] The working principle of the hoop winding tooling is as follows: install the fabric felt reel onto the unwinding roller shaft 82, adjust it to be parallel to the cylinder body, pull out the head of the fabric felt 10, pass it through the guide roller, and insert it into the gap of the slitting roller 84, and continue to pull it down to the pressing roller 85. The fabric felt is tightly fitted to the cylinder through the pressing roller 85, and the fabric felt begins to be wound. At the same time, a sufficient amount of resin matrix is ​​sprayed on the fabric felt to soak the fabric felt. When the fabric felt winding is completed, it can be cut off by the slitting roller 84, and the spraying of the resin matrix is ​​stopped. When the fabric felt is wound on the surface of the inner liner, its head end can be fixed by an auxiliary tape; when the fabric felt is wound on the interlayer toughening buffer layer 31, since the fiber 9 carries glue, its head end can be effectively attached and fixed on the fiber layer of the cylinder. When used for winding the stripping cloth, the fabric felt reel is removed and replaced with the stripping cloth reel, which can be used for stripping cloth winding when the tail yarn is fixed.

[0042] The above are preferred embodiments of the present application, and are not intended to limit the protection scope of the present application in sequence. Therefore, all equivalent changes made based on the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A wrapped gas cylinder, characterized in that: It includes a gas cylinder liner, a fiber winding layer, and a toughening buffer layer; the fiber winding layer includes an alternating circumferential winding layer and a spiral winding layer; the circumferential winding layer is arranged in the barrel section of the gas cylinder liner; the spiral winding layer is arranged in the entire length section of the gas cylinder liner; the toughening buffer layer includes an interlayer toughening buffer layer, and the interlayer toughening buffer layer is arranged in the barrel section between the circumferential winding layer and the spiral winding layer.

2. A wrapped gas cylinder according to claim 1, characterized in that: The innermost layer and the outermost layer of the fiber winding layer are both hoop winding layers.

3. The wrapped gas cylinder according to claim 1, characterized in that: The toughened buffer layer also includes an inner liner surface toughened buffer layer, and the inner liner surface toughened buffer layer is arranged on the entire inner liner surface of the gas cylinder.

4. A wrapped gas cylinder according to claim 3, characterized in that: The inner liner surface toughening buffer layer comprises an inner liner surface toughening buffer layer barrel section and end caps at both ends.

5. The wrapped gas cylinder according to claim 1, characterized in that: The fiber winding layer includes fibers and a resin matrix; the toughened buffer layer includes a fabric felt and a resin matrix, the fabric felt is any one or more of glass fiber felt, carbon felt, and polyester felt, and the resin matrix includes at least any one of polyurethane, modified epoxy resin, and acrylate.

6. A method for preparing a wrapped gas cylinder, based on the wrapped gas cylinder according to any one of claims 1 to 5, characterized in that: Includes steps: A fiber winding layer and an interlayer toughening buffer layer are wound on the gas cylinder liner through a winding production line, specifically comprising: winding the fibers impregnated with the first resin matrix alternately around the circumferential winding layer and the spiral winding layer on the gas cylinder liner according to the layer design; during the winding of the transition layer from the circumferential winding layer to the spiral winding layer, or during the winding of the transition layer from the spiral winding layer to the circumferential winding layer, the fabric felt of the interlayer toughening buffer layer is simultaneously wound for N turns, where N is an integer greater than or equal to 1; the fabric felt is cut off before the winding of the transition layer is completed, and the winding of the fabric felt is stopped; and, during the process of winding the fabric felt of the interlayer toughening buffer layer, a sufficient amount of the second resin matrix needs to be sprayed on the fabric felt to penetrate the fabric felt.

7. The method for preparing a wrapped gas cylinder according to claim 6, characterized in that: The first resin matrix and the second resin matrix are resins of different systems, and the two resins of different systems form an interpenetrating structure when co-cured.

8. The method for preparing a wrapped gas cylinder according to claim 7, characterized in that: Before the fiber winding layer begins to be wound, it is also necessary to first provide a liner surface toughening buffer layer on the outer surface of the cylinder liner, which specifically includes the following steps: The fabric felt is placed in a head forming mold to form a head preform; the head preform is then set at the corresponding position of the gas cylinder liner; the fabric felt is then tightly wound around the gas cylinder liner tube, and both sides of the fabric felt are butted against the head preform; and while winding the fabric felt, a sufficient amount of the second resin matrix needs to be sprayed on the fabric felt to saturate the fabric felt.

9. The method for preparing a wrapped gas cylinder according to claim 6, characterized in that: It also includes the tail yarn fixing, which specifically includes the steps of: Step 1: According to the fiber winding layer design, determine the end position of the fiber of the last fiber winding layer wound around the gas cylinder, so that the fiber after the end position stops infiltrating the resin matrix; Step 2: When the fiber winding of the last fiber winding layer of the wound gas cylinder is completed, the release cloth is wound on the wound gas cylinder from the end position of the fiber, and the fiber that is not impregnated with the resin matrix is ​​continued to be wound while maintaining the winding tension of the wound gas cylinder, so as to form a circumferential dry fiber layer and a release cloth layer with a set width and overlapped and wound on the surface of the wound gas cylinder; Step 3: After the fibers not soaked in the resin matrix and the release cloth are overlapped and wound for 1-2 turns, the winding tension is released, the fibers are cut, and the release cloth is continued to be overlapped for at least half a turn, and then the release cloth is cut and the end of the release cloth is fixed with a high-temperature tape; Step 4: transport the wrapped gas cylinder as a whole to an oven for heating and curing; Step 5: After cooling, remove the high-temperature tape, the demoulding cloth layer, and the circumferential dry fiber layer to obtain a wound gas cylinder with no fiber joints on the surface and with a stable tension.

10. The method for preparing a wrapped gas cylinder according to claim 6, characterized in that The winding production line includes a hoop winding tooling, which includes a mounting plate, a reeling roller, a glue groove, a slitting roller, and a pressure roller. There are two mounting plates, which are arranged opposite to each other; the two ends of the reeling roller are respectively connected and fixed to the two mounting plates; the two ends of the glue groove are respectively provided with a first connecting arm, and the other end of the first connecting arm is connected to the mounting plate; the slitting roller is connected and fixed to the mounting plate through a second connecting arm; and the pressure roller is connected and fixed to the mounting plate through a third connecting arm.

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