DE102017208542A1 - Method for producing a pressure vessel and pressure vessel - Google Patents

Abstract

A method of manufacturing a pressure vessel having at least one fiber reinforced layer 120, wherein the fiber reinforced layer 120 comprises a plurality of fiber layers 122, 126 reinforcing fiber, comprising the step of applying the plurality of fiber layers 122, 126, wherein at least two fiber layers 122, 126 are stretched differently.

Description

The technology disclosed herein relates to a method of manufacturing a pressure vessel and a pressure vessel. Pressure vessels as such are known in the art. In relatively thick-walled pressure vessels, as used for example for the storage of hydrogen in vehicles, there is an uneven utilization of the reinforcing fibers due to the compression of the container wall with increasing internal pressure. This means that more fiber material must be used than would actually be necessary. More fiber material is associated with increased manufacturing costs, space requirements and weight.

It is a preferred object of the technology disclosed herein to reduce or eliminate at least one disadvantage of a previously known solution or to suggest an alternative solution. In particular, it is a preferred object of the technology disclosed herein to provide a low-cost, lightweight and / or space-saving pressure vessel. Other preferred objects may result from the beneficial effects of the technology disclosed herein. The object (s) is / are solved by the subject matter of the independent claims. The dependent claims are preferred embodiments.

The technology disclosed herein relates to a method of manufacturing a pressure vessel. The technology disclosed herein further relates to a pressure vessel (for a motor vehicle (eg passenger cars, motorcycles, commercial vehicles), which may in particular be manufactured according to one of the methods disclosed herein.) The pressure vessel serves to store gaseous fuel under ambient conditions The pressure vessel may be, for example, a cryogenic pressure vessel (= CcH2) or a high-pressure gas vessel (= CGH2) designed to store fuel substantially at ambient temperatures permanently at a nominal operating pressure (also called nominal working pressure or NWP) of about 350 bar (= overpressure relative to the atmospheric pressure), more preferably of about 700 bar or more is suitable to store the fuel at the aforementioned operating pressures even at temperatures that are well below the operating temperature of the motor vehicle.

The pressure vessel comprises at least one fiber-reinforced layer. The fiber-reinforced layer may preferably completely surround a liner at least in regions. The fiber reinforced layer is often referred to as a laminate or armor. Hereinafter, the term "fiber-reinforced layer" is usually used. As a fiber reinforced layer i.d.R. Fiber-reinforced plastics (also abbreviated to FVK or FKV), for example carbon fiber reinforced plastics (CFRP) and / or glass fiber reinforced plastics (GRP). The fiber-reinforced layer suitably comprises reinforcing fibers embedded in a plastic matrix. In particular, matrix material, type and proportion of reinforcing fibers and their orientation can be varied so that the desired mechanical and / or chemical properties are established. Preferably, continuous fibers are used as reinforcing fibers, which can be applied by winding and / or braiding. The fiber reinforced layer has i.d.R. several layers on.

The fiber reinforced layer has multiple fiber layers. The multiple fiber layers may be circumferential layers. The fiber reinforced layer has i.d.R. Cross and peripheral layers on. In order to compensate for axial stresses, cross layers (helical layers) are wound or braided over the entire winding core surface. In the i.d.R. cylindrical peripheral area are i.d.R. so-called "hoop layers", which provide for a reinforcement in the circumferential direction. The circumferential positions extend in the circumferential direction U of the pressure vessel and are oriented at an angle of about 90 ° (+/- 5 °) to the pressure vessel longitudinal axis A-A. In particular, the fiber-reinforced layer may comprise an outer fiber layer, which surrounds an inner fiber layer at least regionally, preferably completely. The outer fiber layer can thus be arranged further out than the inner fiber layer.

The pressure vessel may include a liner. The liner forms the hollow body in which the fuel is stored. The liner may for example be made of aluminum or steel or of their alloys. Further preferably, the liner may be made of a plastic. Preferably, the liner serves as a storage body for the reinforcing fibers of the fiber-reinforced layer. It may also be provided a linerless pressure vessel.

The technology disclosed here is based on the idea that in prior art pressure vessels, the inner layers are more heavily loaded at the same internal pressure as the outer layers. As a result, the material used is not exploited as it would be possible and it is used more material than would actually be necessary. In order to make the stress of the reinforcing fibers in the circumferential direction for different layers more uniform (in particular for pressures in the Range of bursting pressure), the outer (peripheral) layers are to be deposited with a correspondingly more stretched or stretched course, as the inner (peripheral) layers. According to the invention, therefore, different layers are to be stretched to varying degrees. In particular, the outer (circumferential) layers should be stretched more than the inner peripheral layers. Accordingly, the method disclosed herein comprises the step of applying the plurality of fiber layers, wherein at least two fiber layers are stretched differently. In particular, the outer fiber layer can be stretched more than the inner fiber layer

wobei,

c

die Crimp Percentage;

I

die nicht gewellte bzw. verkräuselte Länge der Verstärkungsfaser; und

p

die gewellte bzw. verkräuselte Länge der Verstärkungsfaser ist.

The term "stretching" in the context of this patent application is a measure of the waviness or crimping of the reinforcing fibers. The more a reinforcing fiber is stretched, the lower is its waviness or crimping. As a measure of the draw, the length of the reinforcing fiber in the non-corrugated state may be related to the length in the corrugated but preferably unstretched state. A measure of the stretching is eg "Crimp Percentage". $$\text{C}=\left(\text{I}-\text{p}\right)/\text{p}*100\text{\%}$$

in which,

c

the crimp percentage;

I

the undulated or crimped length of the reinforcing fiber; and

p

is the corrugated length of the reinforcing fiber.

Similarly, the reciprocal of C can be used as a measure. Furthermore, the sum of the amounts of all lateral deviation A ₁₂₂ from an ideal line, in particular a geodesic, be used as a measure of the stretching.

Between the liner and the fiber-reinforced layer, a transport layer (English: breather layer) may be provided. The transport layer may in particular be designed to be permeable to gas in such a way that fuel diffused through the liner can flow into other regions, for example in the direction of the ends of the pressure vessel. For this purpose, the transport layer can form, for example, microchannels or microcolumns. However, such a transport layer does not have to be provided. This transport layer can then form the boundary layer between liner and fiber-reinforced layer disclosed here.

The transport layer itself and / or the liner may have a corrugated structure at least in some areas, preferably in a cylindrical middle part, the inner fiber layer being more conformed to the corrugated structure than the outer fiber layer.

Preferably, both the inner fiber layer and the outer fiber layer are wound. Particularly preferred all fiber layers are wound. It is also conceivable that some or all layers are braided.

1. a. Die Fasern können mit unterschiedlicher Zugkraft abgelegt (z.B. gewickelt) werden. Die höhere Zugkraft bewirkt eine stärkere Verstreckung und umgekehrt. Während der Ablage von Verstärkungsfasern der äußeren Faserlage kann eine Faserablageeinrichtung eine höhere Zugspannung auf die abzulegenden Verstärkungsfasern ausüben als während der Ablage von Verstärkungsfasern der inneren Faserlage.
2. b. Die Verstärkungsfasern und/oder Faserbündel können in unterschiedlichem Maße verdrillt werden. Eine starke Verdrillung entspricht einem wenig verstreckten Verlauf und umgekehrt. Die Verstärkungsfasern der inneren Faserlage können zumindest teilweise stärker verdrillt sein als Verstärkungsfasern der äußeren Faserlage.
3. c. Der Wickelkopf kann bei der Ablage Vibrationen oder Schwingungen senkrecht zum Faserlauf ausführen. Je größer die Amplitude und die Frequenz der Vibrationen bzw. der Schwingungen bei der Ablage ist, desto geringer verstreckt werden die Verstärkungsfasern abgelegt und umgekehrt. Während der Ablage von Verstärkungsfasern der äußeren Faserlage kann eine Faserablageeinrichtung weniger schwingen als während der Ablage von Verstärkungsfasern der inneren Faserlage.
4. d. Der Radius des Ablagekörpers (insbesondere Wickelkörper) kann variiert werden. Im Besonderen können unterschiedliche Radien für Faserablage und Aushärtung zum Einsatz kommen. Beim Aushärten wird der Verstreckungszustand der Verstärkungsfasern dann quasi „eingefroren“. Bevorzugt kann ein (Kunststoff-)Liner, der als Wickelkörper genutzt wird, mit Innendruck beaufschlagt werden. Erfolgt die Ablage bei einem bestimmten Innendruck und erfolgt das anschließende Aushärten bei einem demgegenüber erhöhten Innendruck, bewirkt dies eine Verstreckung der Verstärkungsfasern. Beim Aushärten der äußeren Faserlage kann der Druckbehälter mit einem anderen Innendruck beaufschlagt werden und/oder der Ablagekörper einen anderen Radius aufweisen als beim Aushärten der inneren Faserlage. Dies lässt sich einerseits durch einen stufenweisen Herstellungsprozess, in dem Faserablage und Aushärten jeweils für die einzelnen Lagen sequentiell hintereinander erfolgen, bewirken.

There are various possibilities to vary the stretching of the reinforcing fibers, which can each be used individually or in combination with each other.

1. a. The fibers can be stored with different tensile force (eg wound). The higher tensile force causes a stronger draft and vice versa. During the deposition of reinforcing fibers of the outer fiber layer, a fiber depositing device can exert a higher tensile stress on the reinforcing fibers to be deposited than during the deposition of reinforcing fibers of the inner fiber layer.
2. b. The reinforcing fibers and / or fiber bundles can be twisted to varying degrees. A strong twist corresponds to a slightly stretched course and vice versa. The reinforcing fibers of the inner fiber layer may be at least partially more twisted than reinforcing fibers of the outer fiber layer.
3. c. The winding head can perform vibrations or vibrations perpendicular to the grain during storage. The greater the amplitude and the frequency of the vibrations or the vibrations in the tray, the lower stretched the reinforcing fibers are stored and vice versa. During the deposition of reinforcing fibers of the outer fibrous layer, a fiber depositing device may oscillate less than during the deposition of reinforcing fibers of the inner fibrous layer.
4. d. The radius of the storage body (in particular bobbin) can be varied. In particular, different radii for fiber deposition and curing can be used. During curing, the state of stretching of the reinforcing fibers is then quasi "frozen". Preferably, a (plastic) liner, which is used as a winding body, be subjected to internal pressure. If the deposit takes place at a certain internal pressure and the subsequent curing takes place at a contrast increased internal pressure, this causes a stretching of the reinforcing fibers. When curing the outer fiber layer of the pressure vessel can be acted upon with a different internal pressure and / or the storage body have a different radius than when curing the inner fiber layer. On the one hand, this can be achieved by a step-by-step production process, in which fiber deposition and curing take place sequentially one after the other for the individual layers.

• Verfahren zur Herstellung eines Druckbehälters zur Speicherung von Brennstoff, umfassend die Schritte:
  • - Bereitstellen von einer Außenkontur, und
  • - Ablegen von Verstärkungsfasern der faserverstärkten Schicht des Druckbehälters auf der Innenseite der Außenkontur.

Die Verstärkungsfasern können von mindestens einer Spule abgewickelt werden, die sich nicht im Inneren der Außenkontur befindet. Nach dem Ablegen der Verstärkungsfasern kann die Ablagevorrichtung zur Ablage von Endlosfasern aus dem Inneren der Außenkontur und/oder aus dem Inneren des Druckbehälters herausgeführt werden. Die Ablagevorrichtung kann eine Anpressrolle umfassen, die die Endlosfasern ablegt. Das Verfahren kann ferner den Schritt umfassen: Ausbilden eines Liners auf der Innenseite der faserverstärkten Schicht. Der Liner kann durch Blasformen und/oder durch Rotationsformen ausgebildet werden. Die Verstärkungsfaser können vor dem Ablegen mit Matrixmaterial imprägniert werden. Das Verfahren kann ferner den Schritt umfassen: Einbringen von Matrixmaterial in die faserverstärkte Schicht nachdem die Endlosfasern abgelegt wurden. Vor dem Einbringen von Matrixmaterial kann in die faserverstärkte Schicht der Liner ausgebildet worden sein. Die Verstärkungsfasern können auf der Außenkontur durch mindestens eine beheizte Anpressrolle abgelegt werden, und/oder wobei die Endlosfasern durch Laserschweißen, durch ultraviolette Strahlung, durch elektrostatische Kräfte und/oder durch einen Haftvermittler fixiert werden. Während des Einbringens von Matrixmaterial und/oder während des Aushärtens der faserverstärkten Schicht kann ein Innendruck anliegen.Since, in particular, the outer layers should be stretched more strongly, the production from the outside to the inside, as is the case for example in the German patent application with the application number DE 10 2016 204990 is described, the content of which is hereby incorporated by reference. Thus, the technology disclosed here also includes the following methods:

• Method for producing a pressure vessel for storing fuel, comprising the steps:
  • - Provide an outer contour, and
  • - depositing reinforcing fibers of the fiber-reinforced layer of the pressure vessel on the inside of the outer contour.

The reinforcing fibers can be unwound from at least one coil which is not located inside the outer contour. After depositing the reinforcing fibers, the depositing device for depositing continuous fibers can be led out of the interior of the outer contour and / or from the interior of the pressure vessel. The storage device may comprise a pressure roller which deposits the continuous fibers. The method may further include the step of forming a liner on the inside of the fiber reinforced layer. The liner may be formed by blow molding and / or by rotational molding. The reinforcing fiber may be impregnated with matrix material prior to depositing. The method may further comprise the step of introducing matrix material into the fiber reinforced layer after the continuous fibers have been deposited. Before introducing matrix material, the liner may have been formed in the fiber-reinforced layer. The reinforcing fibers can be deposited on the outer contour by at least one heated pressure roller, and / or wherein the continuous fibers are fixed by laser welding, by ultraviolet radiation, by electrostatic forces and / or by a bonding agent. During the introduction of matrix material and / or during the curing of the fiber-reinforced layer, an internal pressure may be present.

Except in a staged manufacturing process in which fiber deposition and curing are carried out sequentially for the individual layers sequentially, there is still another method in which initially the complete fiber deposition takes place, which is very favorable in terms of production technology. The technology disclosed here relates, as it were, to a process for the production of a pressure vessel in which, after fiber deposition, the inner fiber layer and the outer fiber layer are cured at different time intervals. In the different time intervals, the container interior can be subjected to different internal pressures. Thus, in the different time intervals, the radius of the deposition body and thus the state of stretching, which is "frozen" or fixed during curing, may be different.

The term "curing" in the context of this patent application means that the matrix material is transferred from a liquid state to such a solid state that the matrix material fixes the position of the reinforcing fibers. If the matrix material is a thermoset, the material is converted into the solid state by chemical crosslinking. However, if the matrix material is a thermoplastic, the material passes into the solid state by cooling or solidifying.

The time intervals are different and offset in time. They can overlap easily. Preferably, the curing of inner fiber layer and outer fiber layer take place successively.

For example, the amount of the pressure difference from the internal pressure during the curing of the outer fiber layer compared to the internal pressure during curing of the inner fiber layer may be at least 2 bar, or at least 20 bar, or at least 200 bar.

Particularly preferably, first the outer fiber layer is cured and offset in time later, the inner fiber layer is cured. The internal pressure during the curing of the outer fiber layer may be higher than during the curing of the inner fiber layer. It can thereby be achieved that first the reinforcing fibers of the outer fiber layer are fixed by the matrix material, wherein at the same time the reinforcing fibers of the inner fibers are not fixed. If the internal pressure is reduced even before the inner fiber layer hardens, the pressure vessel contracts. As a result, the reinforcing fibers of the inner fiber layer are less stretched or curled or curled. In this state, the reinforcing fibers of the inner fiber layer are now fixed in the temporally offset time interval.

Alternatively it can be provided that first the inner fiber layer is cured and temporally offset later the outer fiber layer is cured. The internal pressure may be higher during the curing of the outer fiber layer than during the curing of the inner fiber layer. As it is achieved by the fact that the matrix material the Reinforcing fibers of the outer fiber ply fixed in a more stretched state than the matrix material fixed reinforcing fibers of the inner fiber ply.

For this purpose, it can be provided that the inner fiber layer is heated more strongly than the outer fiber layer. According to the method disclosed herein it can be provided that the container interior is heated to an internal temperature which is higher than the outside temperature immediately outside the pressure vessel to be produced. The temperature difference between the inside temperature and the outside temperature can be at least 30 K, at least 50 K or at least 100 K. Furthermore, it can be provided that the environment is cooled immediately outside the pressure vessel during curing. In one embodiment it can be provided that the container interior is filled with a liquid. If the interior of the container is filled with a liquid, the change from the radius of the storage body can be varied more accurately than with a compressible gas. Particularly preferably, the liquid can be heated, so that the liquid emits heat energy from the container interior to the fiber-reinforced layer. In one embodiment, the container interior may comprise a storage body that can be heated by electromagnetic induction and / or electromagnetic radiation.

Alternatively or additionally, the inner fiber layer and the outer fiber layer may comprise various matrix materials which may be formed to cure at the different time intervals.

During the manufacture of the pressure vessel, the reinforcing fibers may be soaked in different matrix materials, for example.

On the other hand, however, the production is particularly preferably carried out in a process without repetitions, ie only by a single fiber deposition, followed by a single curing. This can be achieved, for example, by taking advantage of the limited thermal conductivity of the matrix (which exists both in the uncured state and in the cured state). If the container is heated from the inside (eg by filling with hydraulic fluid, which has an elevated temperature for curing compared to the ambient temperature or pressure vessel outside) while the container outside is heated less than from the inside, not heated or even cooled, then in the Container wall, a temperature gradient arising from the inside out. Accordingly, curing will already take place in the inner container layers, but not yet in the outer container layers (= curing at different time intervals). Over time, the hardening will gradually take place from the inside to the outside. This temporal dependence of the curing of the individual layers can be used by the stretching takes place temporally differently. In particular, therefore, for the curing of the inner layers a lower internal pressure prevail (especially are fixed to reinforcing fibers of the inner layers) and later increased accordingly for the curing of the middle and finally the outer layers. The staggered curing of the individual layers at different time intervals can be optimized by selecting the resin and hardener components of the matrix material (different reaction kinetics). Similarly, the coordinated timing of the internal temperature and the outside temperature can improve the process even more. Thus, it is conceivable to slowly lower the inside temperature from a high temperature while at the same time slowly raising the outside temperature from a low temperature to promote the "wandering" of the zone with the curing temperature from outside to inside through the vessel wall. For detailed design, experiments and thermal simulations help.
In other words, the temperature boundary conditions drive a temperature wave from the inside to the outside through the container wall, which causes a curing zone that migrates from the inside to the outside. By simultaneously increasing internal pressure, the reinforcing fibers are "fixed" from the inside to the outside in an increasingly stretched state.

Advantageously, the potential of the reinforcing fibers can be better utilized in a pressure vessel thus produced by these are mechanically loaded uniformly. For the same material use, strength and / or cycle stability can improve. There is a possibility for material savings without loss of strength, with lower wall thicknesses, lower costs and / or higher storage volume with the same space.

• 1 eine schematische Querschnittsansicht durch den hier offenbarten Druckbehälter 100
• 2 eine schematische Ansicht einer inneren Faserlage 122; und
• 3 eine schematische Ansicht einer äußeren Faserlage 126;

The technology disclosed herein will now be explained with reference to the figures. Show it:

• 1 a schematic cross-sectional view through the pressure vessel 100 disclosed herein
• 2 a schematic view of an inner fiber layer 122 ; and
• 3 a schematic view of an outer fiber layer 126 ;

The more the course of a reinforcing fiber is stretched, the closer it is to an ideal line 10 or approximated to an ideal course. This ideal line 10 also typically corresponds to the case of a wound container Geodesics (cf. 2 and 3 ). A little stretched reinforcing fiber 122 On the other hand, it is only roughly approximated by an ideal line 10 around. Typically, it will be a lateral deviation at most (or even all) locations A ₁₂₂ from the ideal line 10 exhibit. If you add in sections the amounts of lateral deviations A ₁₂₂ from the ideal line 10 , then one obtains a non-zero value, ie nonzero. On the other hand, the vectors of the lateral deviations are added in sections A ₁₂₂ from the ideal line 10 , then they add up to zero on average. The latter is an expression that the deviations around the ideal line 10 done around.

A two-dimensional example of this would be a sinusoid that intersects the midline only at a few points, but is centered on that midline. A three-dimensional example would be a helix curve. This has a lateral deviation from the midline. The lateral deviation has a constant amount here (vectorially), but constantly changes its direction. On average, the helix curve lies on its midline, interestingly enough, without ever cutting or touching this midline. In technical reality lateral deviations become A ₁₂₂ . A ₁₂₆ from the ideal line 10 usually do not have the uniformity of mathematical functions, but have statistical irregularities.

In the 3 becomes the case of a highly stretched outer reinforcing fiber 126 considered close to an ideal line 10 runs. A tensile load Z ₁₂₆ the reinforcing fiber 126 along this ideal line 10 (supported by embedding the reinforcing fiber 126 into the surrounding matrix and the adjacent reinforcing fibers), ie directly stretching the reinforcing fiber 126 cause, but the course of the reinforcing fiber 126 essentially not change. With a correspondingly high basic stiffness of the reinforcing fiber 126 in itself, it will be due to the stretched grain 126 So give a high tensile stiffness for loads along the ideal course.

In the 2 becomes the case of a less stretched inner reinforcing fiber 122 considered. A little stretched reinforcing fiber 122 is compared to the more stretched reinforcing fiber 126 just roughly approximating an ideal line 10 around. On average, it will be a lateral deviation A ₁₂₂ from the ideal line 10 greater than the deviation A ₁₂₆ the more stretched outer reinforcing fiber 126 , A tensile load Z ₁₂₂ this reinforcing fiber 122 along the ideal line 10 is next to an elongation of the reinforcing fiber 122 This is why, above all, the gain fiber tries to optimize its course, ie to stretch and align itself so that the lateral deviations A ₁₂₂ to the ideal line 10 be minimized. In addition to the already mentioned embedding of the reinforcing fiber 122 in the surrounding matrix and the adjacent reinforcing fibers also helps here, that the lateral deviations A ₁₂₂ from the ideal line 10 are relatively small compared to the radius of curvature of the ideal line 10 , The poorly stretched reinforcing fiber 122 becomes with tensile loads Z ₁₂₂ in the ideal direction 10 less stiff than the more stretched reinforcing fiber 126 , In addition to the above-described mechanism of approach to the ideal line 10 at tensile load Z ₁₂₂ . Z ₁₂₆ along the ideal line 10 There is another reason for the low stiffness of the low stretched reinforcing fiber 122 opposite the more stretched reinforcing fiber 126 : The low-stretched reinforcement fiber is considered over a certain section 122 have a greater length than the more stretched reinforcing fiber 126 , The cause is due to the different lateral deviations A ₁₂₂ . A ₁₂₆ from the ideal line 10 , These provide a kind of "detour" for the reinforcing fiber over the ideal line 10 which can also be expressed by the "crimp percentage". If one tries to stretch two reinforcement fibers of equal stiffness by the same absolute amount, this results in the longer reinforcement fiber 122 the lower force, so it is apparently less stiff.

The lateral deviations A ₁₂₂ . A ₁₂₆ were in the 1 . 2 and 3 greatly exaggerated for better visibility. The pressure vessel interior may be, for example, the internal volume itself, which later forms the fuel storage volume, or the liner, if a liner is provided.

The foregoing description of the present invention is for illustrative purposes only, and not for the purpose of limiting the invention. Various changes and modifications are possible within the scope of the invention without departing from the scope of the invention and its equivalents.

LIST OF REFERENCE NUMBERS

10

ideal line

A ₁₂₂ , A ₁₂₆

lateral distance of the fiber from the ideal line

Z ₁₂₂ , Z ₁₂₆

Tensile load along the ideal line

122

little stretched fiber

124

medium stretched fiber

126

heavily drawn fiber

100

pressure vessel

110

shelf body

120

fiber reinforced layer

122

inner fiber layer

124

middle fiber layer

126

outer fiber layer

130

Outside of the pressure vessel wall

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102016204990 [0014]

Claims (13)

A method of making a pressure vessel (100) having at least one fiber reinforced layer (120), the fiber reinforced layer (120) comprising a plurality of fiber layers (122, 126), wherein an outer fiber layer (126) at least partially surrounds an inner fiber layer (122), wherein the inner fiber layer (122) and the outer fiber layer (126) are cured at different time intervals. Method according to Claim 1 , wherein in the different time intervals, the container interior (I) with different internal pressures (Pi) is applied. A method according to any one of the preceding claims, wherein first the outer fiber layer (126) is cured and laterally staggered later the inner fiber layer (122) is cured, and wherein the inner pressure (Pi) is higher during curing of the outer fiber layer (126) as during the curing of the inner fiber layer (122). A method according to any one of the preceding claims, wherein first the inner fiber layer (122) is cured and laterally offset the outer fiber layer (122) is cured, and wherein the inner pressure (Pi) is higher during cure of the outer fiber layer (126) as during curing, the inner fiber layer (122). The method of any preceding claim, wherein the inner fiber layer (122) is heated more than the outer fiber layer (126). A method according to any preceding claim, wherein the fiber reinforced layer (120) surrounds a container interior (I), further comprising the step of: heating the interior of the vessel (I) to an internal temperature (Ti) higher than the outside temperature (Ta) immediately outside from the pressure vessel (100). Method according to one of the preceding claims, wherein a temperature difference between the internal temperature (Ti) and outside temperature (Ta) is at least 30K, 50K or 100K. Method according to one of the preceding claims, wherein the environment immediately outside of the pressure vessel (100) is cooled at least temporarily. Method according to one of the preceding claims, wherein the container interior (I) is filled with a liquid. Method according to Claim 9 wherein the liquid releases heat energy to the fiber reinforced layer (120). Method according to one of the preceding claims, wherein the container interior comprises a storage body (110) which is heated by electromagnetic induction and / or electromagnetic radiation. The method of any one of the preceding claims, wherein the inner fiber layer (122) and the outer fiber layer (126) comprise different matrix materials formed to cure the various matrix materials at the different time intervals. Method according to Claim 12 wherein during the manufacture of the pressure vessel (100) continuous fibers are impregnated with different matrix materials.

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