Method for manufacturing a tank for storing a fluid under pressure and a tank obtained thereby

Abstract

The present invention relates to a method for manufacturing a tank, in particular a tank for storing a fluid under pressure, comprising an elongated densified textile element, said method comprising: step (i) of manufacturing an undensified elongated textile preform comprising a plurality of layers of thermoplastic composite tapes each comprising at least one tape wound at a predetermined angle, by means of a specific device (1); step (ii) of densifying the preform obtained in the previous step by heating and cooling the thermoplastic composite tapes, whereby the preform is densified and a densified elongated textile element is obtained; the preform being manufactured by a method comprising the steps of implementing feeding means (6) in each of the modules (4), said feeding means (6) comprising a selected tape (10), said selected tape (10) comprising at least a thermoplastic composite tape; setting the forward speed V1 and the rotational speed V2 of each of the modules (4) and activating each module (4); cutting the elongated element (11) and / or using up the supply of the tape (10); and recovering the obtained undensified elongated textile preform (11); step i) not including the step of braiding the tapes.

Description

Technical Field

[0001] The present invention relates to a tank for storing a pressurized fluid, in particular hydrogen, comprising an elongated textile element, and a method for manufacturing the same.

Background Art

[0002] The present invention relates to a tank for storing a gas, in particular a compressed gas, at high pressure, comprising a specific elongated textile element, and a method for manufacturing the same.

[0003] One of the objectives to be achieved in the field of transportation, in particular in the automotive field, is to propose vehicles with less and less pollution. Thus, electric vehicles or hybrid vehicles including batteries aim to gradually replace internal combustion engine vehicles such as gasoline vehicles or diesel vehicles. However, it has been found that the battery is a relatively complex component of the vehicle. Depending on the position of the battery in the vehicle, it may be necessary to protect the battery from impacts and the external environment, which can be extreme temperatures and various humidities. It is also necessary to prevent the risk of fire.

[0004] Furthermore, the battery of an electric vehicle or a hybrid vehicle usually accounts for 10 - 30% of the vehicle weight. Such excessive weight leads to various drawbacks such as excessive consumption of fuel or energy.

[0005] Also, it is important to ensure that the operating temperature of the vehicle does not exceed 55°C in order not to damage the battery cells and maintain their service life. Conversely, for example, in winter, it may be necessary to raise the temperature of the battery to optimize its operation.

[0006] In addition, electric vehicles still have several problems, such as the autonomy of the battery, the use of rare earths in the battery, which is not an inexhaustible resource, and the problem of producing electricity in each country to be able to charge the battery.

[0007] Hydrogen can be converted into electricity by a fuel cell and used to power an electric vehicle, so it can be an alternative to an electric battery.

[0008] However, since the molecular weight of hydrogen is very low and its liquefaction temperature is very low, hydrogen storage is technically difficult and costly, especially in the case of mobile storage. However, in order to store it effectively, it should be stored in small quantities, and for this purpose, it is necessary to keep hydrogen under high pressure considering the temperature at which the vehicle is used. This is particularly true for fuel cell hybrid road vehicles that require an autonomy of about 600 - 700 km in addition to battery - based power, or a lower autonomy basically for use in urban areas.

[0009] Hydrogen tanks are generally composed of a metal or polymer shell (also called a liner), and the diffusion of hydrogen to the outside of the shell should be prevented. The first shell should be protected by a second housing (generally made of composite materials) that is designed to withstand the internal pressure of the tank (e.g., 700 bar) and possible impacts or heat sources. Furthermore, the tank should include a valve system that must be safe.

[0010] According to Sheet 4.2 of the Memorandum on Hydrogen from the French Association for Hydrogen and fuel cells (AFHYPAC - Association Francaise pour l’hydrogene et la pile a combustible) revised in December 2016, the storage and distribution of hydrogen under pressure has been a standard practice for many years, using steel or metal cylinders or cylinder assemblies reinforced with fiber material windings on the outside, pressurized to 20 or 25 MPa (Type I and II). The drawback of such a storage method is that the size is only 14 kg / m at 20 MPa and normal temperature (21°C), while in the case of methane, it is 100 kg / m 3 only, whereas in the case of methane, it is 100 kg / m 3and is particularly heavy. This results from using steel at a low stress level to avoid the problem of embrittlement caused by hydrogen. With the emergence of the so-called Type IV composite tank technology, the situation has changed fundamentally. The basic principle of the above-mentioned tank is to separate two essential functions, namely leak prevention and mechanical resistance, in order to manage one independently of the other. In the above-mentioned type of tank, a bladder made of (thermosetting or thermoplastic) resin called a leak prevention liner or sheath is associated with a reinforcing structure made of fibers (glass, aramid, carbon) impregnated with a thermosetting resin, called a reinforcing sheath or layer. The above-mentioned type of tank reduces the weight of the tank and enables it to operate at much higher pressures while preventing the risk of explosive rupture in the event of severe external attacks. As a result, a pressure of 70 MPa (700 bar) is actually the current standard.

[0011] In Type IV tanks, the leak prevention layer and the reinforcing layer do not adhere to each other and are often made of different materials that can cause the collapse of the leak prevention layer. Both the accumulation of gas at the interface between the leak prevention layer and the reinforcing layer and the decrease in the internal pressure of the tank occur simultaneously. Furthermore, the drying of Type IV tanks after a hydrostatic test has a risk of collapse of the leak prevention layer, so it can only be dried under vacuum, which is time-consuming and costly.

[0012] Such problems have led to the development of Type V tanks (so-called 4.5-type tanks) based on using the same polymer in the matrix of the leak prevention layer and the reinforcing layer, or at least a polymer compatible with the polymer constituting the composite matrix, in order to provide excellent weldability and durability between the two layers, and thereby obtain a single-block tank. Such types of tanks are still in the R & D stage.

[0013] To manufacture a composite shell, a method of using an epoxy resin as the matrix of a composite material is known for manufacturing a tank having a high glass transition temperature (hereinafter, Tg), i.e., the Tg can exceed 100°C. A drawback of composite materials containing thermosetting resins, particularly epoxy resins, is that after curing of the thermosetting resin, even after a certain number of pressurization / depressurization cycles caused by the filling / discharge cycle, the composite material generally develops microcracks, which can cause significant variability or even loss of mechanical strength. To predict such a performance degradation over time, it is necessary to increase the carbon fiber content, and thus increase the weight and cost of the tank.

[0014] Furthermore, in the case of thermosetting resins, particularly epoxy resins, the microcracks affect the impermeability of the composite reinforcement, so it is necessary to use a thick leak prevention layer inside the tank (i.e., a type IV tank).

[0015] Finally, from the perspective of recyclability, current type IV tanks use a reinforcing layer made of a thermosetting resin, particularly epoxy resin, which is not recyclable.

[0016] However, despite the improvements made to type IV tanks, type IV tanks still have drawbacks. In particular, there is a need to accelerate the filling rate of the tank. Also, the temperature resistance of gas tanks, particularly hydrogen tanks, is too low with current solutions. Accelerating the filling rate of the tank is advantageous for consumers, particularly in reducing costs, without the further need to cool hydrogen to -60°C prior to filling.

[0017] The use of a polyphthalamide reinforcing layer (hereinafter referred to as PPA) with a high glass transition temperature (hereinafter Tg) is of great advantage from the viewpoint of mechanical resistance at high temperatures. Furthermore, since the above type of resin is thermoplastic, it helps to obtain a tank that can be easily recycled. Due to the thermoplasticity of the resin, the level of microcracks in the composite shell is reduced, thereby strengthening the mechanical resistance of the composite shell, reducing the variability of the mechanical resistance, significantly reducing the amount of carbon fiber used, and thus significantly reducing the cost and carbon footprint of a type V tank compared to a type IV tank. Furthermore, due to the semi-crystallinity of the resin, the leak prevention property against gases, particularly hydrogen, is improved. Therefore, the composite shell contributes to the impermeability of the tank, thereby reducing the thickness of the leak prevention layer, and thus reducing the cost and weight of the leak prevention layer inside the tank.

[0018] However, the manufacture of such types of tanks by winding a high-temperature composite tape around the leak prevention layer of a thermoplastic polymer causes difficulties related to the generation of significant residual stresses of thermal origin, which are inherent in the difference in expansion of the materials involved, and more particularly the difference in expansion between the fibers and the polymer constituting the leak prevention layer, during the cooling of the tank at the end of its manufacture. The above problem is particularly exacerbated in the case of a PPA matrix constituting a carbon fiber composite reinforcement. In fact, the high temperature required for using a composite tape containing PPA is the main cause of additional residual stresses inside the tank due to the high melting point and high Tg of such types of resins. When the tank includes a molding insert of a polyamide resin with a low Tg, typically around 50 °C, the above residual stresses can cause deformation of the insert and prevent the complete manufacture of the tank, particularly the fastening of the base that closes the tank. When the container is of type V (or 4.5, i.e., the polymer constituting the matrix of the composite material has different properties from the polymer of the leak prevention layer, but the two polymers are compatible with each other and remain weldable), and the tank has a polyamide leak prevention layer with a low Tg, and more particularly an aliphatic polyamide leak prevention layer, the residual stresses can cause delamination within the composite reinforcement layer.

[0019] Furthermore, the manufacturing methods of such composite tanks are generally time-consuming and costly. Therefore, conventionally, based on the wet filament winding or hot winding of thermoplastic composite tapes, a cycle time of several hours is required to manufacture a single-piece composite tank of 60 liters or more. Furthermore, such methods have been found to be inefficient for tank sizes below a certain size, typically below 30 liters. Finally, due to the presence of porosity associated with the low pressure applied during the use of fibers pre-impregnated with resin during wet impregnation or in-situ densification of thermoplastic composite tapes, the quality of the resulting composite is incomplete.

[0020] Therefore, the conventional methods for manufacturing such composite tanks cannot easily and efficiently manufacture a compatible composite tank, i.e., a tank that can be inserted into a volume with a complex and / or narrow shape in at least one of the three dimensions, such as the volume of a battery pack. One of the most promising types of compatible tanks is an assembly of small-diameter composite tubes (typically with a diameter <200 mm) connected to each other by pipes. However, as described above, with current methods, typically a 60-liter tank can be manufactured integrally, so the overall size is large and it is impossible to insert it into at least a battery pack, and the above methods are not suitable for manufacturing small-diameter tubular tanks.

[0021] Therefore, today, there is a need for a simple, rapid, and inexpensive process that can manufacture tanks with excellent mechanical strength even at high temperatures, recyclable, compatible, and excellent in gas leakage prevention. Such tanks are useful for storing not only hydrogen but also all types of gases under pressure, especially high pressure.

[0022] Therefore, what is currently required is a tank that has excellent mechanical resistance at high temperatures, is recyclable and compatible, has excellent gas leakage prevention, and is easy to manufacture. Such tanks are useful for storing not only hydrogen but also all types of gases under pressure, especially high pressure. SUMMARY OF THE INVENTION

[0023] Such problems are solved by the method of the present invention comprising the following two steps.

[0024] In the first step i) of manufacturing an unconsolidated elongated fabric preform, said preform comprises at least one thermoplastic composite tape of a plurality of layers, preferably a plurality of layers of tapes, each layer comprising a tape wound at a predetermined angle without being crimped, and said preform is obtained by a specific apparatus shown in FIG. 1.

[0025] In the second step ii), the fabric preform obtained in the above-described step is consolidated, particularly under pressure.

[0026] The said method has a plurality of advantages.

[0027] First of all, in order to stack a plurality of layers of woven or knitted tapes, it is necessary to pass through the same layer. Different from the methods including knitting or weaving, the production of the preform by step i) of the method of the present invention can be carried out continuously, so that a large-sized, particularly a fabric preform with a small diameter and a long length can be obtained quickly and inexpensively.

[0028] Furthermore, by step i) of the method of the present invention, it becomes possible to stack a very large number of layers, and the preform may include the same number of tape layers as the number of modules used.

[0029] The apparatus implemented in step i) implements a guide for deploying the tape along the same direction. Thereby, this apparatus enables the production of elongated fabric preforms of various shapes, regardless of whether they are cylindrical or not. The preform obtained by step i) may include a cross-sectional limiting part, in which specific tapes are cut, welded, and inserts are arranged, especially before consolidation. Similarly, the preform can be easily bent at room temperature to give a specific non-linear shape and then frozen during the consolidation step ii). However, for that, a specific selection of the fiber orientation in different layers of the preform is required. Thereby, the method serves to easily obtain a compatible tank that can be inserted, in particular, into a volume similar to that of an automotive battery pack.

[0030] Advantageously, step ii) enables co-consolidation of a thermoplastic or metal insert with the tapes of the fabric preform in a single step, and in particular, enables the production of a tank by closing a tube, which is a further economic advantage of the method for manufacturing a tank according to the present invention. Furthermore, co-consolidation can improve the mechanical strength and / or cohesion between the insert and the elongated fabric element co-consolidated therewith.

[0031] Thereby, according to a first aspect, the present invention relates to a method for manufacturing a tank comprising a consolidated elongated fabric element, in particular a tank for storing a fluid under pressure, the method comprising step (i) of manufacturing, by means of an apparatus (1), an unconsolidated elongated fabric preform comprising a plurality of layers of thermoplastic composite tapes each comprising at least one tape wound at a predetermined angle; step (ii) of consolidating the fabric preform obtained in the previous step by heating and cooling the thermoplastic composite tapes, whereby the preform is consolidated and a consolidated elongated fabric element is obtained; the apparatus (1) comprising a frame (2) and at least two modules (4); The frame (2) includes a main longitudinal guide (3) along the direction X, and the guide (3) is attached to the frame (2), The at least two modules (4) are arranged in series along the direction X around the guide (3), and each module (4) A feeding crown (5) surrounding a part of the guide (3), Arranged on the feeding crown (5), at least one tape (10) is fed towards the guide (3) at a winding angle of -90° to 90° with respect to the direction X and at a forward speed V1, and each tape (10) winds around at least the periphery of the guide (3) or the upper layer of the tape (10), a feeding means (6), Drive means (15) for driving the feeding crown (5) to rotate with respect to the guide (3) at a rotational speed V2, The preform Implementing a feeding means (6) in each of the modules (4), the feeding means (6) includes a selected tape (10), and the selected tape (10) includes at least a thermoplastic composite tape, Parameterizing the forward speed V1 and the rotational speed V2 of each of the modules (4) and starting each module (4), Cutting the elongated element (11) and / or using up the tape (10), Recovering the obtained unconsolidated elongated fabric preform (11), Manufactured by a method including Step i) does not include any step of braiding the tape.

[0032] In some embodiments, the method according to the invention further includes one or more of the following additional features.

[0033] The thermoplastic composite tape includes continuous or discontinuous reinforcing fibers of an inorganic material and a thermoplastic polymer composition.

[0034] The reinforcing fibers of the inorganic material are impregnated in the core with a thermoplastic polymer composition or pre-impregnated, or mixed with the fibers of the thermoplastic polymer.

[0035] The thermoplastic composite tape includes continuous fibers impregnated with a composition containing a thermoplastic polymer. When the thermoplastic polymer is amorphous, the glass transition temperature (Tg) measured according to ISO 11357-3:2013 standard is higher than 80°C, preferably 100°C or higher, more preferably higher than 120°C. When the thermoplastic polymer is semi-crystalline, the melting point is higher than 150°C.

[0036] The thermoplastic polymer composition of the composite tape mainly includes polyamide, preferably semi-crystalline polyamide.

[0037] The polyamide is an aliphatic, alicyclic or semi-aromatic polyamide.

[0038] The aliphatic polyamide is selected from PA5, PA5-10, PA6, PA66, PA6-10, PA6-12, PA6-18, PA9, PA10-10, PA10-12, PA11, PA12 and mixtures thereof.

[0039] The semi-aromatic polyamide is selected from PA MPMDT / 6T, PA11 / 6T, PA11 / 10T, PA11 / BACT, PA5T / 10T, PA11 / 6T / 10T, PA MXDT / 4T, PA MXDT / 6T, PA MXDT / 10T, PA MPMDT / 4T, PA MPMDT / 6T, PA MPMDT / 10T, PA BACT / 10T, PA BACT / 6T, PA BACT / 4T, PA BACT / 10T / 6T, PA11 / BACT / 4T, PA11 / BACT / 6T, PA11 / BACT / 10T, PA11 / MXDT / 4T, PA11 / MXDT / 6T, PA11 / MXDT / 10T, PA11 / MPMDT / 4T, PA11 / MPMDT / 6T, PA11 / MPMDT / 10T, PA11 / MXDT / 10T, PA11 / 5T / 10T and mixtures thereof.

[0040] The fibers of the thermoplastic composite tape are selected from glass fibers, carbon fibers, basalt or basalt-containing fibers.

[0041] The fibers of the thermoplastic composite tape are unidirectional, i.e., all are oriented along the length of the tape.

[0042] The fiber content of the composite tape accounts for 40 - 70 vol%, preferably 50 - 60 vol% of the thermoplastic composite tape.

[0043] The selected tape (10) further includes a non-composite thermoplastic polymer tape (10).

[0044] The non-composite thermoplastic polymer tape (10) occupies a small mass fraction of the preform compared to the mass fraction of the thermoplastic composite tape.

[0045] The polymer composition forming the non-composite thermoplastic polymer tape (10) mainly includes polyamide, preferably semi-crystalline polyamide.

[0046] The thermoplastic polymer composition of the thermoplastic composite tape (10) and the thermoplastic polymer composition of the non-composite thermoplastic polymer tape (10) are compatible, especially identical.

[0047] The thickness of the tape (10) is 50 - 300 μm, especially 50 - 260 μm, more especially 60 μm - 170 μm.

[0048] The width of the tape (10) is 5 mm - 50 mm, especially 10 mm - 15 mm.

[0049] The winding angle of the tape (10) is +90° to -90° with respect to direction X.

[0050] The winding angle is equal to + / -54.8° to + / -10°, preferably + / -5°, more preferably + / -1°.

[0051] The fabric preform produced in step i) includes cross-sectional variations, in particular successive cross-sectional variations along direction X.

[0052] Step ii) is carried out within a mold, in particular outside the preform, and more particularly within a closed mold.

[0053] In step ii), the pressure is applied by a bladder inside the preform.

[0054] Prior to step ii), an insert is placed at the end of the preform obtained in step i), preferably outside the end of the preform.

[0055] The insert is possibly made of a composite thermoplastic material.

[0056] In step ii), the insert is co-consolidated with the tape (10) during the consolidation step ii).

[0057] According to a second aspect, the invention relates to a tank, in particular for storing a fluid, more particularly hydrogen, under pressure, comprising at least one consolidated elongated fabric element obtained by the method of the invention.

[0058] In some embodiments, the tank according to the invention includes one or more of the following additional features.

[0059] Each consolidated elongated fabric element is provided with inserts at its ends.

[0060] The insert is an insert that seals the consolidated elongated element, or an insert having an opening for fluid inlet and outlet.

[0061] The tank includes a plurality of consolidated elongated fabric elements connected in series with each other via connectors.

[0062] The inventors were able to show that a tank containing the consolidated elongated fabric element obtained by the method of the present invention has very excellent mechanical strength compared to composite tanks of the prior art.

[0063] In fact, in contrast to conventional methods involving the weaving of composite tapes, the method of the present invention enables the tape to be wound without crimping, thereby preventing local excessive stress at the intersections of the fibers, and thus improving the mechanical strength of the consolidated elongated fabric element obtained after consolidation.

[0064] Advantageously, the consolidation step ii) can be carried out under pressure, in particular under a pressure of 5 to 10 bar, which further improves the mechanical strength and can reduce the porosity of the composite material.

[0065] In conventional methods using wet filament winding or winding of thermoplastic composite tapes, the quality of consolidation is usually very low because high pressure cannot be applied, especially for a long time.

[0066] Furthermore, the inventors observed that by the step ii) of consolidating the preform under pressure, the obtained consolidated elongated fabric element is given a very low residual porosity, in particular less than 5%, more particularly less than 2%, which enhances the barrier effect exerted by the liner of type IV or 4.5 tanks and further helps to obtain type V tanks by omitting the liner.

[0067] Furthermore, according to another advantage, when the thermoplastic polymer composition forming the composite tape is a semi-crystalline thermoplastic polymer or contains a semi-crystalline thermoplastic polymer, in particular is or contains polyphthalamide, the crystallization of the resin during the cooling step can advantageously further improve the barrier effect of the tank against fluids under pressure.

[0068] Advantageously, by the step of densifying the preform within a closed mold, it is also possible to reduce the thermal oxidation of the resin that occurs when the thermoplastic tape is placed in the atmosphere, thereby contributing to the improvement of the mechanical properties of the resulting composite tubular structure.

[0069] According to a third aspect, the present invention relates to an undensified elongated fabric preform obtained by step i) of the method according to the present invention.

[0070] According to a fourth aspect, the present invention relates to a battery pack, particularly for a motor vehicle, comprising a hydrogen storage tank according to the present invention.

[0071] According to a fifth aspect, the present invention relates to the use of the device according to the present invention, particularly shown in FIGS. 1 to 11, for manufacturing a tank according to the present invention.

Brief Description of the Drawings

[0072]

Figure 1

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Figure 10

Figure 11

[0073] Note that in the figures, structural and / or functional elements common to different variations may have the same reference numerals.

DETAILED DESCRIPTION OF THE INVENTION

[0074] The present invention will be described in the following more detailed and non-limiting manner.

[0075] Unless otherwise specified, all percentages relating to quantities are volume percentages.

[0076] <Method for manufacturing a tank> According to a first aspect, the present invention relates to a method for manufacturing a tank, in particular a tank for storing a fluid under pressure, comprising a densified elongated textile element, said method comprising: step (i) of manufacturing an undensified elongated textile preform comprising a plurality of layers of thermoplastic composite tapes each comprising at least one tape wound at a predetermined angle, by means of an apparatus (1); step (ii) of densifying the textile preform obtained in the previous step by heating and cooling the thermoplastic composite tapes, whereby the preform is densified and a densified elongated textile element is obtained; said apparatus (1) comprising a frame (2) and at least two modules (4); said frame (2) comprising a main longitudinal guide (3) along a direction X, said guide (3) being attached to the frame (2); said at least two modules (4) being arranged in series along the direction X around the guide (3), each module (4) comprising: a feed crown (5) surrounding a part of the guide (3); feeding means (6) arranged in the feed crown (5) for feeding at least one tape (10) towards the guide (3) at a winding angle of -90° to 90° with respect to the direction X and at a forward speed V1, each tape (10) winding around at least the periphery of the guide (3) or the upper layer of the tape (10); driving means (15) for driving the feed crown (5) to rotate relative to the guide (3) at a rotational speed V2, The preform is implementing a feeding means (6) in each of the modules (4), the feeding means (6) including a selected tape (10), the selected tape (10) including a thermoplastic composite tape; setting a forward speed V1 and a rotational speed V2 for each of the modules (4) and starting each module (4); cutting the elongate element (11) and / or using up the tape (10); recovering the resulting unconsolidated elongate fabric preform (11); manufactured by a method including Step i) does not include any step of braiding the tape.

[0077] - Step i)- Step i) includes manufacturing an unconsolidated elongate fabric preform using what is called a fabric tape, more particularly a thermoplastic composite tape. Step i) is carried out by a specific apparatus shown in FIGS. 1 to 11.

[0078] As defined by the present invention, the tape is called a fabric and thus includes fibers, for example unidirectional carbon fibers, which are then a matter of dry fibers. The tape suitable for the present invention has a tendency to wrap around the guide and includes a structure rigid enough to remain wrapped around the guide.

[0079] Step i) of manufacturing the preform does not include any step of braiding the tape. Thereby, step i) serves to manufacture an unconsolidated elongate fabric preform that is not crimped, i.e., an elongate fabric preform in which the crimping (denoted by E) is less than 0.5%, preferably 0%.

[0080] "Uncrimped", as defined by the present invention, means that the constituent tapes of the fabric are not wavy.

[0081] The length of the fabric is always shorter than the length of the constituent yarns or tapes, because crossing the warp yarns or tapes with the weft yarns (or, in the case of knitted or woven fabrics, yarns / tapes in different directions) consumes length. The above difference is crimping, expressed as a percentage. Crimping is exemplified by the fact that the yarns or tapes in the fabric have "undulations" perpendicular to the local plane of the fabric.

[0082] Crimping E increases with the cross - over density between different directions of the fabric, knitted fabric and more generally fabrics including out - of - plane undulations of their yarns or tapes. Crimping E is defined as a percentage as follows. E=(L - L0) / L0×100

[0083] L is the length of the fabric and L0 is the length of the straight yarn or tape obtained from the fabric of length L. A crimping of less than 0.5%, preferably 0%, theoretically corresponds to the yarn being fully taut, i.e., to a state where there are no undulations.

[0084] [Thermoplastic composite tape] The term "thermoplastic composite tape" refers to a tape comprising fibers of an inorganic material and a thermoplastic polymer composition that melts under the influence of temperature and then solidifies, thereby consolidating the preform.

[0085] More particularly, the thermoplastic composite tape used in step i) may comprise continuous or discontinuous reinforcing fibers of an inorganic material and a thermoplastic polymer composition.

[0086] In some embodiments, the thermoplastic composite tape is impregnated with a thermoplastic polymer composition in a core (commonly referred to as a "tape"), or is pre - impregnated with a composition of a thermoplastic polymer, especially in powder form, or It is mixed with fibers of a thermoplastic polymer and contains fibers of an inorganic material, which is generally called a "co-blended tape".

[0087] In a preferred embodiment, the thermoplastic composite tape is a tape impregnated with a thermoplastic polymer composition in a core.

[0088] In some embodiments, the thermoplastic composite tape comprises continuous fibers impregnated with a composition containing a thermoplastic polymer, and when the polymer is amorphous, the glass transition temperature (Tg) measured according to ISO 11357-3:2013 standard is higher than 80 °C, preferably 100 °C or higher, more preferably higher than 120 °C, and when the polymer is semi-crystalline, the melting point is higher than 150 °C.

[0089] In some embodiments, the thermoplastic polymer composition of the composite tape mainly comprises polyamide, preferably semi-crystalline polyamide.

[0090] In some embodiments, the polyamide is an aliphatic, alicyclic or semi-aromatic polyamide.

[0091] The aliphatic polyamide may be selected from PA5, PA5-10, PA6, PA66, PA6-10, PA6-12, PA6-18, PA9, PA10-10, PA10-12, PA11, PA12 and mixtures thereof.

[0092] The semi-aromatic polyamide may be selected from PA MPMDT / 6T, PA11 / 10T, PA11 / BACT, PA5T / 10T, PA11 / 6T / 10T, PA MXDT / 4T, PA MXDT / 6T, PA MXDT / 10T, PA MPMDT / 4T, PA MPMDT / 6T, PA MPMDT / 10T, PA BACT / 10T, PA BACT / 6T, PA BACT / 4T, PA BACT / 10T / 6T, PA11 / BACT / 4T, PA11 / BACT / 6T, PA11 / BACT / 10T, PA11 / MXDT / 4T, PA11 / MXDT / 6T, PA11 / MXDT / 10T, PA11 / MPMDT / 4T, PA11 / MPMDT / 6T, PA11 / MPMDT / 10T, PA11 / MXDT / 10T, PA11 / 5T / 10T, and mixtures thereof.

[0093] The fibers of the composite tape may be selected from glass fibers, carbon fibers, basalt, or basalt-containing fibers.

[0094] The fibers of the thermoplastic composite tape are preferably unidirectional, which in such cases means that all the fibers are oriented in the same direction, i.e., along the length of the tape. The tape can also be composed of multiple layers of fibers that are overlapped with each other and have different orientations for each layer, but even in such cases, the fibers are non-woven and / or non-knitted.

[0095] In some embodiments, the fiber content of the composite tape occupies 40 - 70 vol%, preferably 50 - 60 vol% of the material forming the composite tape. The percentage of the fibers can be determined by well-known methods such as the method described in ISO 14127:2008.

[0096] In some embodiments, the selected tape (10) further comprises a non-composite thermoplastic polymer tape (10).

[0097] In another embodiment, the non-composite thermoplastic polymer tape (10) occupies a small mass fraction of the preform compared to the mass fraction of the thermoplastic composite tape.

[0098] In yet another embodiment, the polymer composition of the non-composite thermoplastic polymer tape (10) mainly comprises a polyamide, preferably a semi-crystalline polyamide.

[0099] In a variant of the embodiment, the thickness of the tape (10) is 50 - 300 μm, particularly 50 - 260 μm, and more particularly 60 μm - 170 μm.

[0100] In a variant of the embodiment, the width of the tape (10) is 5 mm - 50 mm, particularly 10 mm - 15 mm.

[0101] The tape is arranged towards the guide at a winding angle that is strictly greater than -90° and strictly less than 90° with respect to the feed direction X of the fabric element.

[0102] In other words, the winding angle of the tape (10) with respect to the direction X is in the range of +90° to -90°, excluding the limits of +90° and -90°.

[0103] In some embodiments, the winding angle is equal to + / -54.8° to + / -10°, preferably + / -5°, and more preferably + / -1°.

[0104] According to one embodiment of the present invention, the method further comprises the step of changing the diameter or cross-section (when not related to a tube having a circular cross-section) of the elongated element. Means other than the implementation of the secondary guide can be used to expand or contract the diameter or cross-section (when not related to a tube having a circular cross-section) of the elongated element.

[0105] The fabric preform obtained at the end of step i) generally comprises a plurality of layers, particularly the same number of layers as the number of modules (4) used. Each layer is formed by winding a tape having the same or different properties as the tape of at least one adjacent layer.

[0106] Thereby, the non-composite thermoplastic tape can be inserted, in particular, between two layers of thermoplastic composite tapes and / or can form the inner layer of the preform, thereby forming the inner layer of the consolidated elongated fabric element. The inner layer formed by the non-composite thermoplastic tape can, in particular, function as a barrier layer against the fluid contained in the tank.

[0107] In some embodiments, the thermoplastic polymer compositions of the thermoplastic composite tape (10) and the non-composite thermoplastic polymer tape (10) are compatible, and more particularly, are completely or partially miscible, and in particular are identical.

[0108] The overall or partial compatibility of the compositions enabling welding is the difference in the glass transition temperatures of the two compositions present in the interfacial layer produced by welding and is defined by the ratio consisting of the difference in the glass transition temperatures of the two compositions before mixing the two compositions by welding.

[0109] When the ratio is equal to 0 in absolute value, the compatibility is complete, and when the ratio is different from 0 in absolute value and less than 1, the compatibility is partial. The complete immiscibility between the polyamide contained in the composition forming the leak prevention layer and the polyamide contained in the composition impregnating the fiber material of the intermediate layer is excluded. Similarly, the complete immiscibility between the polyamide contained in the composition impregnating the fiber material of the intermediate layer and the polyamide in the composition impregnating the fiber material of the outer layer is excluded.

[0110] Advantageously, when the compatibility of the composition is partial, the ratio is less than 30% in absolute value, preferably less than 20%.

[0111] In some embodiments, the glass transition temperature of the mixture is within the range of the glass transition temperature of the polyamide before mixing and differs from the glass transition temperature of the polyamide by at least 5 °C, preferably at least 10 °C, depending on whether the compatibility is complete or partial.

[0112] The expression "completely compatible" means, for example, that two polyamides, designated PAa and PAb, each having Tga and Tgb respectively, are present in two adjacent leak - prevention layers or reinforcing layers, and when Tga is less than Tgb, the mixture of the two polyamides has only one Tgab, and its value is included between Tga and one Tgb.

[0113] Advantageously, when the compatibility of the above - mentioned composition is partial, the ratio is less than 30% in absolute value, and preferably less than 20%.

[0114] In some embodiments, the glass transition temperature of the mixture is within the range of the glass transition temperatures of the above - mentioned polyamides before mixing, depending on whether the compatibility is complete or partial, and it should be at least 5°C, preferably at least 10°C different from the glass transition temperatures of the above - mentioned polyamides.

[0115] The expression "completely compatible" means, for example, that two polyamides, designated PAa and PAb, each having Tga and Tgb respectively, are present in two adjacent layers, and when Tga is less than Tgb, the mixture of the two polyamides has only one Tgab, and its value is included between Tga and one Tgb.

[0116] And the Tgab value is at least 5°C, more particularly at least 10°C higher than Tga, and at least 5°C, more particularly at least 10°C lower than Tgb.

[0117] The expression "partially compatible" means, for example, that when two polyamides, designated PAa and PAb, each having Tga and Tgb respectively, are present in two adjacent leak - prevention layers or reinforcing layers, the mixture of the two polyamides has two Tgs, Tg’a and Tg’b, and Tga < Tg’a < Tg’b < Tgb.

[0118] The Tg’a value and the Tg’b value are at least 5°C, more particularly at least 10°C higher than Tga, and at least 5°C, more particularly at least 10°C lower than Tgb.

[0119] Due to the immiscibility of the two polyamides, two Tgs, namely Tga and Tgb, will be present in the mixture of the two polyamides, and these respectively correspond to the Tgs of the pure polymers used individually, namely Tga and Tgb.

[0120] The glass transition temperature of the mixture of the two polyamides may be the same as or different from the temperature before mixing, but if the two polyamides are reactive with each other, it is not outside the scope of the present invention.

[0121] According to another embodiment, the preform may comprise a plurality of layers of thermoplastic composite tapes, and the thermoplastic polymers may have the same or different properties compared to the thermoplastic polymers of adjacent layers.

[0122] The preform can comprise up to 50 layers, particularly 47 layers. In particular, the preform may comprise 10 layers of non-composite thermoplastic tapes and 37 layers of thermoplastic composite tapes. In some embodiments, the preform comprises an inner layer of 10 layers of non-composite thermoplastic tapes that form a leak prevention layer after consolidation, and 10 to 50 layers of thermoplastic composite tapes, particularly 37 layers of thermoplastic composite tapes, more particularly 37 layers of thermoplastic composite tapes impregnated in the core, which form a reinforcing layer.

[0123] In a variation of the embodiment, the fabric preform produced in step i) comprises a change in cross-section, particularly a narrowing of the cross-section, more particularly a sequential narrowing of the cross-section along direction X.

[0124] In some embodiments, the elongate element is cut at the site of the cross-sectional narrowing and, if necessary, an insert can be placed therein.

[0125] According to one feature of the present invention, each module of the apparatus for manufacturing the preform includes independent feeding means. Thereby, each module can distribute tapes of different properties. The properties and dimensions of the tapes may vary from layer to layer.

[0126] According to another feature of the present invention, the main longitudinal guide includes a substantially circular or polygonal cross-section, or a free-form cross-section. The resulting elongated element can have the shape of a tube or a more complex shape, depending on the use.

[0127] According to still another feature of the present invention, the feeding means includes at least one tape dispenser arranged around the feeding crown. The implementation of the tape dispenser enables easy storage of the tape and distribution to the main guide, and the tape dispenser can rotate around the guide based on the rotational speed of the feeding crown.

[0128] According to one embodiment of the present invention, the tape dispenser includes pivoting means on the feeding crown. The use of the pivoting means serves to direct the distribution of the tape towards the guide, thereby selecting the angle between the tape and the guide within the range of -90° to 90°. All tapes of the same module have substantially the same angle with the guide.

[0129] According to another embodiment of the present invention, the tape dispenser includes at least one guillotine for cutting at least one tape emerging from the tape dispenser, and an electric element for moving the tape towards the guide.

[0130] According to another embodiment of the present invention, the tape dispenser includes welding means, for example ultrasonic welding means, for welding the tape to an existing layer or upper layer. Other welding means adapted to the nature of the tape used are possible within the concept of the present invention. When the diameter or cross-section of the elongated element (when not related to a tube having a circular cross-section) changes, it is advantageous to add or remove one or more tapes, which is possible within the context of the present invention by use of guillotines and / or welding means.

[0131] According to an embodiment of the present invention, the apparatus further includes a tension assisting device for guiding the tape of the module.

[0132] Using tension assistance facilitates the sliding of the tapes of different layers along the main guide. An example of an embodiment of the tension assisting device may be a system of at least one roller arranged downstream of the last module along direction X. The roller applies sufficient pressure for the layer of tape to slide on the main guide.

[0133] Depending on the nature of the tape, the assisting device can be removed during the manufacture of a fabric element that can advance alone on the guide due to its rigidity. According to another embodiment, the nature of the tape does not require any tension assistance.

[0134] According to a variant of an embodiment of the present invention, the apparatus further includes a secondary longitudinal guide having a diameter or cross-section (when not related to a tube having a circular cross-section) larger than that of the main guide and moving on the main guide. When the apparatus is operating, using the secondary guide having a larger diameter or cross-section increases the diameter or cross-section of the elongated element (when not related to a tube), and the tape is arranged on the secondary guide.

[0135] The forward speed V1 corresponds to the forward speed of the fabric element on the main guide. Therefore, the forward speed V1 is substantially the same as the respective forward speeds of the modules. The forward speed V1 and the rotational speed V2 of each module are, on the one hand, related to the angle and the feed speed defined between the tapes fed by each of the modules.

[0136] According to one embodiment of the invention, the method further comprises the step of storing the elongate element wound around a storage reel. By the method according to the invention, it is possible to manufacture a fairly long elongate element, which can reach, for example, 1 kilometer until the tape feeding means are used up. Storing the elongate element on a reel at the outlet of the device facilitates handling.

[0137] According to a variant of an embodiment of the invention, the method further comprises the step of assisting the tension of the tape by means of a tension assisting device. The tension assistance is arranged downstream of the last module transporting the last layer of the fabric element. The operator can, for example, guide the tape of each layer to the tension assistance, which then helps to slide the different layers onto the main guide.

[0138] According to one embodiment of the invention, the storage reel is a tension assisting device for the tape from the feeding means of the modules of the manufacturing device.

[0139] According to one embodiment of the invention, the method further comprises the additional step of arranging a secondary longitudinal guide on the first module and moving the secondary guide along the direction X. The secondary guide can enlarge the diameter or the cross-section (if not related to a tube) of the manufactured elongate element, or can reduce the diameter or the cross-section of the element if a first secondary guide is already used.

[0140] According to one embodiment of the invention, the method further comprises the step of bending the obtained elongate element at the ambient temperature to a desired angle. The advantage of the manufacturing device is that the elongate element can be bent at room temperature.

[0141] As defined herein, "ambient temperature" means a temperature of 15 to 25 °C.

[0142] - Step ii)- Next, the elongated fabric preform obtained in step i) is consolidated by heating and cooling the thermoplastic composite tape.

[0143] More particularly, the elongated fabric preform is consolidated by melting and cooling the thermoplastic composite tape.

[0144] The heating and cooling steps serve to weld together the tapes of the different layers forming the preform. Thus, the heating temperature is determined according to the nature of the selected tape (10).

[0145] Step ii) is generally carried out at a pressure of 1 bar to 25 bar, particularly 5 bar to 10 bar, more particularly 6 bar to 8 bar.

[0146] Step ii) may be carried out in a mold, particularly outside the preform, more particularly in a closed mold.

[0147] According to an embodiment of step ii), the pressure is applied by a bladder inside the preform.

[0148] According to yet another embodiment of step ii), an insert is placed at the end of the preform obtained in step i), preferably outside the end of the preform. In other words, the inner surface of the insert may be in contact with the outer surface of the preform.

[0149] The insert may particularly be made of metal and may also be made of a thermoplastic material, optionally a composite material.

[0150] Thereby, during step ii), the insert is preferably co-consolidated with the tape of the preform during the consolidation step ii). When pressure is applied by a bladder inside the preform, the tape of the preform is pressed against the inner wall of the insert, thereby obtaining in particular excellent consolidation of the preform and also improving the welding, and thus the mechanical resistance, between the preform and the insert.

[0151] In such an embodiment, when the winding angle of the tape around the axis of the tube or hollow body is greater than 65°, it is preferable to periodically cut the tape to facilitate its consolidation.

[0152] <Tank> According to another aspect, the present invention relates to a tank, in particular a tank for storing a fluid, more particularly hydrogen, under pressure, comprising at least one consolidated elongated textile element obtained by the method described above.

[0153] Each consolidated elongated textile element generally has inserts provided at their ends. Each consolidated elongated textile element particularly comprises at least one insert provided with an opening for the passage of fluid, and optionally an insert for sealing and consolidating the elongated element at one of their ends.

[0154] The consolidated elongated textile elements may each include an insert provided with an opening for the passage of fluid at each of their ends. In such a case, the consolidated elongated textile elements are usually connected to other elongated elements via connectors.

[0155] In some embodiments, the tank comprises a plurality of elongated elements connected in series with each other via connectors.

[0156] More particularly, the first compacted elongate fabric element in series is provided with an insert including an opening for receiving fluid, the last compacted elongate fabric element is provided with an insert for sealing it, and the intermediate compacted elongate fabric elements are each equipped with an insert provided with an opening capable of circulating fluid between the first and the last elongate elements in series at their respective ends.

[0157] Advantageously, the tank is compatible and can be inserted into a very small volume, particularly a battery pack for a motor vehicle.

[0158] <Preform> According to yet another aspect, the invention relates to an uncompacted elongate fabric preform obtained by step i) of the method defined above.

[0159] <Battery pack> According to yet another aspect, the invention relates to a battery pack for a motor vehicle, in particular, comprising a tank for storing the fluid defined above, and more particularly hydrogen.

[0160] <Detailed Description of the Drawings> The device according to the invention, shown in FIGS. 1 and 2 and generally designated by reference numeral 1, is intended for the manufacture of uncompacted elongate fabric elements. For this purpose, the device 1 includes a frame 2 including a main longitudinal guide 3 along a direction X, and at least two modules 4 arranged in series along the direction X around the guide 3.

[0161] The main longitudinal guide 3 is fixed to the frame 2. According to the illustrated embodiment, the main longitudinal guide 3 has a circular cross section and thus has a tubular shape. Such a form does not limit the invention, and other forms of the guide 3 are also compatible with the invention. The guide 3 may be linear and have a cross section of different shapes such as square, rectangular, quadrilateral, triangular, polygonal, circular, elliptical, or a mixed and / or free form.

[0162] The module 4 of the device 1 according to the invention includes, on one side, a feed crown 5 that surrounds a part of the main longitudinal guide 3. According to the illustrated example, the feed crown 5 has a substantially disk-like form that includes a central hole in which the guide 3 is located.

[0163] On the other side, the module 4 includes feed means 6 arranged on the feed crown 5. In the illustrated embodiment, the feed means 6 are arranged on one face of the disk and feed at least one tape 10 towards the guide 3 at an angle between -90° and 90° with respect to the direction X.

[0164] The tape 10 that conforms to the invention is, on the one hand, flexible enough to be wound around the guide 3. Figure 3 shows the elongated element 11 obtained by the device 1 according to the invention. The continuous layers of tapes 10 arranged at different angles enable the obtained elongated element 11 to maintain its shape. Figure 4 shows a cross-section of the elongated element 11 in which the continuous layers are visible.

[0165] The feed means 6 arranged on the crown 5 feed at least one tape 10 towards the guide 3 at a selected angle between -90° and 90° with respect to the direction X. Each tape 10 is wound around at least the periphery of the guide 3 or around a layer of tapes 10 already present, i.e., the upper layer, at a selected overall forward speed V1.

[0166] Each module 4 also further includes drive means 15 for the crown 5. According to Figure 2 and as also seen in Figure 5, the drive means 15 are located on the face of the crown 5 opposite to the feed means 6. The drive means 15 for the crown 5 serve to rotate the crown 5 around the guide 3 at a rotational speed V2. According to the illustrated embodiment, the drive means 15 include a motor that includes, in particular, a belt for rotating the crown 5, and a control unit for the motor to achieve the rotational speed V2 of the crown 5. Such a configuration does not limit the invention.

[0167] The devices shown in FIGS. 1 and 2 include two modules 4. The feeding means 6 of the first module 4 includes two dispensers 20 of the tape 10, and the feeding means 6 of the second module 4 includes only one dispenser 20 of the tape 10. The feeding means 6 of different modules 4 are actually independent of each other. Thereby, each module 4 can transport tapes 10 of different natures and the number of tapes 10 selected for each layer.

[0168] FIG. 6 shows a module 4 including six dispensers 20 of the tape 10. The dispensers 20 of the tape 10 are arranged around the feeding crown 5. According to the illustrated embodiment, the dispenser 20 of the tape 10 includes a reel 21 fixed to one side of the crown 5 by rotating means 22.

[0169] According to the illustrated embodiment, but not limited thereto, the rotating means 22 includes a fixing part 23 and a rotating part 24 directed towards the reel 21. The reel 21 can rotate freely within the rotating part 24, and the rotating part can rotate freely with respect to the fixing part 23. Thereby, the reel 21 can be arranged in a desired configuration, and the rotating means 22 can block in a desired arrangement of the dispenser 20.

[0170] FIG. 7 shows a specific embodiment of the present invention, and the dispenser 20 of the tape 10 further includes a guillotine 25 for cutting the tape 10 at the outlet of the dispenser 20, a motor M for feeding the cut tape, and ultrasonic welding means 26 for welding the tape 10 to an existing layer or an upper layer of the tape 10. The illustration of the motor M, the guillotine 25, and the welding means 26 is schematic in FIG. 7, and other embodiments, particularly embodiments having means acting on the tape 10 outside the dispenser 20, are possible.

[0171] Figures 8 and 9 show specific embodiments of the present invention. The apparatus 1 includes three modules 4. The first module 4 includes four dispensers 20 of the tape 10, and each dispenser 20 arranges the tape 10 along the forward direction X, that is, the angle between the tape 10 and the guide 3 is 0 degrees. The second module 4 includes two dispensers 20 of the tape 10, and finally, the third module 4 includes only one dispenser 20 of the tape 10. Such an embodiment does not limit the present invention.

[0172] To manufacture the elongated element 11 according to the present invention, the first step is to implement the feeding means 6 in each of the modules 4 of the apparatus 1. For this purpose, according to the illustrated example, the reels 21 each containing the selected tape 10 are arranged on each feeding crown 5 of the apparatus 1.

[0173] Preferably, the reel 21 feeds the same tape 10 for each module, and each module 4 may include different types of tape reels 10.

[0174] According to the example shown in Figures 8 and 9, the tape 10 used has a width of 20 - 10 mm and a thickness of about 150 microns.

[0175] The second step of the method is to parameterize one with the forward speed V1 and the other with the rotational speed V2 of each of the modules 4. By accurately adjusting and setting the two values, it is possible to define the desired angle between the tape 10 and the guide for each feeding means 6, and the angle varies between -90° and 90° except for two interval limits. For example, according to the example of the apparatus shown in Figures 8 and 9, the first layer of the tape 10 is arranged at an angle close to 0° with respect to the direction X, the second layer of the tape 10 is arranged at an angle of about 80° with respect to the direction X, and the third layer is arranged at an angle close to -80° with respect to the direction X.

[0176] An example of the configuration is to define the forward speed V1 to be substantially 1 meter per minute and the rotational speed V2 of each of the two modules 4 that distribute the tape 10 to be substantially 360 revolutions per minute. This example does not limit the present invention.

[0177] Next, the module 4 is activated.

[0178] Depending on the nature of the tape 10, a tension assisting device 30 is implemented to assist in pulling the tape 10 from different layers of the element 11. According to the embodiments shown in FIGS. 8 and 9, the first layer of the tape 10 coming from the first module 4 slides on the main guide 3 and passes through the other two modules 4 that have been used. The first layer of the tape 10 can slide alone if possible by its nature or can be manually slid. The tapes 10 of the other layers are arranged on the previous layer and then pass through the tension assisting device 30. The assisting device 30 is not necessarily required for the implementation of the method, but depending on the nature of the tape 10 used, it can assist the different layers in sliding in the direction X.

[0179] In particular, according to a specific embodiment in which the first layer of the tape is arranged at an angle close to 0° with respect to the direction X, manual assistance is not necessarily required to advance the tape 10.

[0180] According to another embodiment, when the other layers of the tape 10 are superimposed on the first layer, the elongated element 11 is manufactured without assistance, the tension assisting device 30 becomes unnecessary and can be removed. Depending on the nature of the tape 10 used, a transition period for starting the assistance may be required if the tape cannot be effectively deployed from its reel 21.

[0181] The manufactured elongated element 11 can be wound around a storage reel for storage, which facilitates subsequent handling. The elongated element 11 can also be cut during manufacture according to the desired size and additional steps described below, for example, an increase or decrease in dimensions.

[0182] According to one embodiment (not shown), the storage reel is an auxiliary device for pulling the tape 10. In fact, during its wound state, the tape 10 forming the fabric element 11 is pulled by the fabric element 11.

[0183] When the elongated element 11 is of the desired size, the elongated element 11 can be cut. Another way to end the method is to wait until the tape 10 is used up.

[0184] The obtained fabric and the unconsolidated elongated element 11 can be finally recovered. If the dimensions permit, a consolidation step, for example, a thermoforming step, can then be applied. During the consolidation of the elongated element 11, the dimensions of the elongated element 11, especially its circumference, can also be slightly changed by about 10 - 20%.

[0185] According to a particular embodiment, a secondary longitudinal guide (not shown) is arranged in the first module 4 during manufacture. The secondary guide having a diameter or cross-section larger than the diameter or cross-section of the main guide 3 is arranged upstream of the first module 4 and moves in the manufacturing direction of the elongated element 11. Next, the tapes 10 of different modules 4 are arranged on the secondary guide and then arranged again on the main guide 3 after passing through the secondary guide. Thereby, the diameter or cross-section or overall shape of the elongated element 11 can also be significantly increased during its manufacture. Such an elongated element 11 is shown in FIG. 10.

[0186] When the diameter or cross-section increases, a tape 10 similar to the tape 10 fed by the corresponding module 4 can be added by ultrasonic welding means 26, thereby filling the openings that may be formed by the increase in the surface of the elongated element 11. In such an example shown in FIG. 10, when the diameter of the element 11 increases, a tape 10 is added to the layer under the upper layer, and when the diameter of the element 11 decreases, the tape 10 is cut.

[0187] According to another embodiment of the present invention, the elongated element 11 obtained by the apparatus 1 is bent at a desired angle at the ambient temperature, like the elongated element 11 shown in FIG. 11. When enabled by the bending rigidity of the obtained elongated element 11, the step of bending at the ambient temperature can be performed manually.

[0188] According to another embodiment (not shown), the elongated element 11 can also be consolidated by incorporating a solid matrix into one of the layers of the tape 10 constituting it.

[0189] Of course, within the framework of the appended claims, various other modifications can be made to the present invention.

Example

[0190] <(Example 1 according to the present invention)> The resin constituting the matrix of the thermoplastic composite tape is 11 / BACT / 10T, the fibers used are Hyosung 2550 G10 carbon fibers, and the fiber content is 53 vol%.

[0191] The tensile stress at break in the 0° (fiber direction) of the composite material obtained with the composite tape is 2700 MPa. The tape has an average width of 17 inches and a thickness of 137 μm.

[0192] In the preform, the thermoplastic composite tape is arranged at positions of + / - 55° from the axis of the tubular tank. The preform has a cross-sectional restriction corresponding to half of the initial diameter, thereby enabling the metal inserts to be arranged outside both ends of the preform.

[0193] The preform includes 37 layers of thermoplastic composite tape.

[0194] The preform was continuously manufactured at a speed of 1 m / min.

[0195] The preform is consolidated at 300 °C under a pressure of 6 bar. The temperature rise time, the time held at 300 °C, and the cooling time are 20 minutes each.

[0196] The tank is of type V, i.e., it has no additional leak - proof layer, and the composite reinforcement not only withstands the pressure but also guarantees such function.

[0197] The tubular tank has a total length of 123 m, an inner diameter of 110 mm at the central part, 55 mm at the restricted part, and the transition part between the central part and the restricted part is conical at an angle of 45 degrees. The thickness of the composite reinforcement is 5 mm. The structural stacking does not include any knitting, and the crimping E is less than 0.5%. The burst pressure of the tank is 1605 bar.

[0198] The obtained tubular tank has a capacity of 10 liters and contains 2.98 kg of composite material.

[0199] <Example 2 (According to the present invention)> The resin constituting the matrix of the thermoplastic composite tape is 11 / BACT / 10T, the fiber used is Hyosung 2550 G10 carbon fiber, and the fiber content is 53 vol%.

[0200] The tensile stress at break in the 0° (fiber direction) of the composite material obtained with the composite tape is 2700 MPa. The tape has an average width of 17 inches and a thickness of 137 μm.

[0201] Within the preform, the thermoplastic composite tape is arranged at positions of + / - 55° from the axis of the tubular tank. The preform has a restricted part with a cross - section corresponding to half of the initial diameter, thereby enabling the placement of a metal insert inside the preform.

[0202] The preform includes, on average, a 10 - layer thermoplastic tape made of polyamide 11 with a width of 17 inches and a thickness of 200 μm, and 37 - layer thermoplastic composite tapes with a width of 17 inches and a thickness of 137 μm.

[0203] The preform was continuously manufactured at a speed of 1 m / min.

[0204] The preform is consolidated at 300 °C under a pressure of 6 bar. The temperature rise time, the holding time at 300 °C and the cooling time are 20 minutes.

[0205] The resin constituting the matrix of the thermoplastic composite tape is 11 / BACT / 10T, the fiber used is Hyosung 2550 G10 carbon fiber, and the fiber content is 55 vol%. The width of the tape is 17 inches. The structural stacking does not include any knitting, and the crimping E is less than 0.5%.

[0206] The tubular tank has a length of 1.33 m, an inner diameter of 110 mm at the central part of the composite reinforcement, 55 mm at the restricted part, and the transition part between the central part and the restricted part is conical at an angle of 45 degrees. The thickness of the composite reinforcement is 5 mm, and the thickness of the leak prevention layer of polyamide 11 obtained by consolidating the thermoplastic tape contained in the preform is 2 mm. Therefore, the inner diameter of the tank is 106 mm at the central part and 51 mm at the restricted part.

[0207] The two layers are completely integrally welded, and the tank is of an integral type. This type of tank is type 4.5 (although the leak prevention layer and the matrix layer of the composite material have different chemical properties, the two resins are partially miscible, enabling complete welding between them).

[0208] The burst pressure of the tank is 1620 bar.

[0209] The obtained tubular tank has a capacity of 10.15 liters and contains 3.22 kg of composite material and 0.89 kg of polyamide 11 liner.

[0210] <Example 3 (according to the present invention)> Connect six tubular tanks as described in Example 2 by connection with a fitting having a diameter of 25 mm (including screw connection) to form an H2 tank suitable for an automobile with a capacity of approximately 61 liters. The tank composed of six tubular tanks can withstand the same pressure of 1620 bar as when using the six tubular tanks individually. The consolidation of the six preforms was carried out in parallel at 300 °C under a pressure of 6 bar in six different closed molds. The temperature rise time, the time held at 300 °C, and the cooling time were 20 minutes.

[0211] The total weight of the composite material used is 19.3 kg.

[0212] The total manufacturing time of the fully compatible tank is 39 minutes, as follows: Manufacturing time of the preform 6 × 1.21 = 7.26 minutes + cutting time, i.e., a total of 8 minutes until the preform is ready for consolidation. 3 minutes for placing the six preforms into the mold together with the inserts. Molding time of 20 minutes for consolidating the six preforms. Ejection time of 3 minutes for the six preforms, and Assembly time of 5 minutes for connecting the six tubular tanks to each other.

[0213] <Example 4 (Comparison)> The structure of the automobile tank has an internal volume of 61 liters, an outer diameter of 400 mm, a length of 0.88 m (including the bottom), and a burst pressure of 1610 bar.

[0214] The tank is of type IV, has a composite reinforcement with a weight of 36.7 kg on the outside, and a polyethylene leak prevention layer with a weight of 5 kg on the inside. The leak prevention layer and the composite reinforcement are not adhered.

[0215] The composite reinforcement is composed of an epoxy matrix and carbon fibers (ref. T700S) manufactured by Toray, with a fiber content of 70 wt% or 59 vol% (the density of the carbon fibers used is 1.8, and the density of the epoxy resin is 1.1). The composite reinforcement is manufactured by wet filament winding. The dry fibers are unwound from the creel and impregnated with resin by passing them through a solution bath containing a liquid precursor of the epoxy resin at a speed of 0.8 m / s at room temperature. Four strands are wound around the liner simultaneously. Each carbon strand contains 1,200 filaments (carbon strand 12K) and has a linear density of 0.83 g / m. When the fiber content is 70 wt%, the linear density of each impregnated strand is 1.18 g / m. Thus, the entire operation of winding four strands in parallel at 0.8 m / s continues for approximately 2.7 h. After such steps, the resin is polymerized in an oven at 60 °C for 8 h.

[0216] Therefore, the manufacturing time of the Type IV tank is much longer than that of the compliant Type V tank of Example 3 according to the present invention, consumes much more composite material, and thus, since the price of carbon fiber is a major factor in the cost of the tank, it can be seen that it is considerably heavier and more expensive. This shows that the effectiveness of the composite reinforcement of the Type IV tank is at least twice lower than that of the composite material constituting the Type V tank of Example 3. In fact, in order to withstand the same internal pressure of 1,600 bar while accommodating the same volume of hydrogen gas (61 l), the Type IV tank made of an epoxy-carbon composite material requires approximately twice as much composite material as a compliant tank made of a PPA-carbon composite material.

Claims

1. In a method for manufacturing a tank, particularly a tank for storing a fluid under pressure, comprising a densified elongated fabric element, a step (i) of manufacturing an undensified elongated fabric preform comprising a plurality of layers of thermoplastic composite tapes each comprising at least one tape wound at a predetermined angle, by means of an apparatus (1); a step (ii) of densifying the undensified elongated fabric preform obtained in the previous step by heating and cooling the thermoplastic composite tapes, whereby the undensified elongated fabric preform is densified and a densified elongated fabric element is obtained, said apparatus (1) comprising a frame (2) and at least two modules (4); said frame (2) comprising a main longitudinal guide (3) along a direction X, said main longitudinal guide (3) being attached to the frame (2); said at least two modules (4) being arranged in series along the direction X around the main longitudinal guide (3), each module (4) comprising a feed crown (5) surrounding a part of the main longitudinal guide (3); feeding means (6) arranged in the feed crown (5) for feeding at least one tape (10) towards the main longitudinal guide (3) at a winding angle of -90° to 90° with respect to the direction X and at a forward speed V1, each tape (10) being wound around at least the main longitudinal guide (3) or on top of said tape (10); driving means (15) for driving the feed crown (5) to rotate around the main longitudinal guide (3) at a rotational speed V2; and said undensified elongated fabric preform being manufactured by a method comprising a step of implementing feeding means (6) in each of said modules (4), said feeding means (6) comprising a selected tape (10), said selected tape (10) comprising at least a thermoplastic composite tape; a step of setting the forward speed V1 and the rotational speed V2 of each of said modules (4) and starting each module (4); a step of cutting the elongated element (11) and / or using up the tape (10); a step of recovering the obtained undensified elongated fabric preform; and said step i) not including any step of braiding the tapes, method.

2. Said thermoplastic composite tape comprises continuous or discontinuous reinforcing fibers of an inorganic material, The method according to claim 1, comprising a thermoplastic polymer composition.

3. The reinforcing fibers of the inorganic material are impregnated in the core with the thermoplastic polymer composition or pre-impregnated, or mixed with the fibers of the thermoplastic polymer, the method according to claim 2.

4. The thermoplastic composite tape comprises continuous fibers impregnated with a composition containing a thermoplastic polymer, and the composition has a glass transition temperature (Tg) measured according to ISO 11357-3:2013 higher than 80 °C, preferably 100 °C or higher, more preferably higher than 120 °C when the thermoplastic polymer is amorphous, and a melting point higher than 150 °C when the thermoplastic polymer is semi-crystalline, the method according to any one of the preceding claims.

5. The thermoplastic polymer composition of the thermoplastic composite tape mainly comprises polyamide, preferably semi-crystalline polyamide, the method according to any one of claims 2 to 4.

6. The polyamide is an aliphatic, alicyclic or semi-aromatic polyamide, the method according to claim 5.

7. The aliphatic polyamide is selected from PA5, PA5-10, PA6, PA66, PA6-10, PA6-12, PA6-18, PA9, PA10-10, PA10-12, PA11, PA12 and mixtures thereof, the method according to claim 6.

8. The semi-aromatic polyamide is selected from PA MPMDT / 6T, PA11 / 6T, PA11 / 10T, PA11 / BACT, PA5T / 10T, PA11 / 6T / 10T, PA MXD T / 4T, PA MXD T / 6T, PA MXD T / 10T, PA MPMDT / 4T, PA MPMDT / 6T, PA MPMDT / 10T, PA BACT / 10T, PA BACT / 6T, PA BACT / 4T, PA BACT / 10T / 6T, PA11 / BACT / 4T, PA11 / BACT / 6T, PA11 / BACT / 10T, PA11 / MXD T / 4T, PA11 / MXD T / 6T, PA11 / MXD T / 10T, PA11 / MPMDT / 4T, PA11 / MPMDT / 6T, PA11 / MPMDT / 10T, PA11 / MXD T / 10T, PA11 / 5T / 10T and mixtures thereof, the method according to claim 7.

9. The method according to any one of the preceding claims, wherein the fibers of the thermoplastic composite tape are selected from glass fibers, carbon fibers, basalt or basalt-containing fibers.

10. The method according to any one of the preceding claims, wherein the fibers of the thermoplastic composite tape are unidirectional, i.e., all are oriented along the length of the tape.

11. The method according to any one of the preceding claims, wherein the fiber content of the thermoplastic composite tape occupies 40 to 70 vol%, preferably 50 to 60 vol% of the thermoplastic composite tape.

12. The method according to any one of the preceding claims, wherein the selected tape (10) further comprises a non-composite thermoplastic polymer tape (10).

13. The method according to claim 12, wherein the non-composite thermoplastic polymer tape (10) occupies a small mass fraction of the preform compared to the mass fraction of the thermoplastic composite tape.

14. The method according to claim 13, wherein the polymer composition forming the non-composite thermoplastic polymer tape (10) mainly comprises polyamide, preferably semi-crystalline polyamide.

15. The method according to claim 14, wherein the thermoplastic polymer composition of the thermoplastic composite tape and the polymer composition of the non-composite thermoplastic polymer tape (10) are compatible, particularly identical.

16. The method according to any one of the preceding claims, wherein the width of the tape (10) is 50 to 300 μm, particularly 50 to 260 μm, and more particularly 60 μm to 170 μm.

17. The method according to any one of the preceding claims, wherein the width of the tape (10) is 5 mm to 50 mm, particularly 10 mm to 15 mm.

18. The method according to any one of the preceding claims, wherein the winding angle of the tape (10) is +90° to -90° with respect to direction X.

19. The method according to claim 18, wherein the winding angle is + / −54.8° to + / −10°, preferably + / −5°, and more preferably + / −1°.

20. The method according to any one of the preceding claims, wherein the unconsolidated elongated fabric preform produced in step i) includes a change in cross-section, particularly a sequential change in cross-section along direction X.

21. The method according to any one of the preceding claims, wherein step ii) is carried out in a mold, in particular outside the unconsolidated elongated fabric preform, and more particularly in a closed mold.

22. The method according to any one of the preceding claims, wherein during step ii), the pressure is applied by a bladder inside the unconsolidated elongated fabric preform.

23. The method according to any one of the preceding claims, wherein prior to step ii), an insert is placed at the end of the unconsolidated elongated fabric preform obtained in step i), preferably outside the end of the unconsolidated elongated fabric preform.

24. The method according to claim 23, wherein the insert is made of a composite thermoplastic material as required.

25. The method according to claim 23 or 24, wherein in step ii), the insert is co-consolidated with the tape (10) during the consolidation step ii).

26. A tank, in particular for storing a fluid, more particularly hydrogen, under pressure, comprising at least one consolidated elongated fabric element obtained by the method according to any one of claims 1 to 25.

27. The tank according to claim 26, wherein each consolidated elongated fabric element is provided with an insert at its ends.

28. The insert is The tank according to claim 27, which is an insert for sealing the consolidated elongated fabric element or an insert having an opening for fluid inlet and outlet.

29. The tank according to any one of claims 26 to 28, comprising a plurality of consolidated elongated fabric elements connected in series with each other via connectors.

30. An unconsolidated elongated fabric preform obtained by step i) of the method according to any one of claims 1 to 25.

31. A battery pack, in particular for a motor vehicle, comprising a tank for storing hydrogen according to any one of claims 26 to 29.

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