Vehicle pressurized gas tank

Abstract

The invention relates to a pressurized gas tank (3) for a vehicle, comprising: - a liner (7) made of plastic material, - a composite reinforcement structure (9) wrapped around the liner (7), characterized in that the tank (3) comprises: - an electric heating device (11) configured to maintain the liner (7) at a temperature above a predetermined threshold, the electric heating device (11) comprising a temperature-self-regulating heating strip (21), the heating strip (21) being disposed between the liner (7) and an external surface (23) of the composite reinforcement structure (9). The invention also relates to a vehicle comprising such a tank, a method for manufacturing such a tank, and a method for thermally regulating such a tank. Figure for the abstract: Figure 2

Description

Title of the invention: Vehicle pressurized gas tank

[0001] The invention relates to the field of vehicle pressurized tanks, such as those for motor vehicles, trucks, buses, trains, or boats. More particularly, the invention relates to a vehicle pressurized gas tank, as well as a vehicle comprising such a pressurized gas tank.

[0002] The art is already known, for example, a pressurized gas tank configured to store gas at a pressure of at least 350 bar or at least 700 bar, the gas being, for example, hydrogen. Thus, this pressurized gas tank is configured to be used by the vehicle equipped with the pressurized gas tank for various functions, as an energy source.

[0003] Such a pressurized gas tank is conventionally composed of an inner casing called a liner, which provides a seal against the gas contained in the tank. The liner is made, for example, of a plastic material, chosen for its lightness and low manufacturing cost, or of a metal such as aluminum, or of another material such as a metal alloy. The liner is generally cylindrical in shape and has two domed ends. The liner has an opening, which is usually covered by a nozzle. The pressurized fluid exerts strong stresses on the inner surface of the liner, which can compromise the integrity of the liner and cause dangerous leaks, particularly with combustible gases such as hydrogen.

[0004] To improve the mechanical properties of the pressurized gas tank, the liner is surrounded by a composite reinforcement structure, generally made by winding around the liner strips of composite material based on thermosetting polymer, for example based on epoxy resin, loaded with glass and / or carbon fibers, or by winding around the liner a filament made of a reinforcing fiber, for example carbon fiber, the filament being embedded in a resin, for example an epoxy resin, to facilitate winding and ensure that the outer surface of the liner is covered.

[0005] Furthermore, such a pressurized gas reservoir generally includes a functional component attached to the nozzle, which supports functional components such as a solenoid valve, in order, for example, to distribute the fluid from the reservoir to a combustion engine and / or to an energy conversion means on board the vehicle, such as a fuel cell, configured to supply energy to the vehicle's propulsion means, such as an electric motor.

[0006] During the distribution of gas from the pressurized gas tank, the temperature of the gas stored in the pressurized gas tank decreases. It is necessary that this The temperature must not fall below a predetermined threshold, for example, -40°C, to prevent damage to the components of the pressurized gas tank, particularly the liner, due to the materials used in its construction. It is known to heat a pressurized gas tank to prevent damage to the liner when the temperature of the gas inside is too low, for example, by placing a heating element inside the tank, within the internal space defined by the liner. However, such a heating element occupies a significant amount of space within the tank, thus reducing its storage capacity. A known alternative is to place an external heating element, such as a heating band, around the pressurized gas tank.However, this heating element does not allow for rapid and efficient heating of the liner because it is separated from the liner by components of the pressurized gas tank that limit heat transfer, such as the composite reinforcement structure. Furthermore, it is necessary to limit the heating power to prevent the heating element from damaging, even locally, the tank components, such as the liner, due to excessive temperatures, for example, above 85°C.

[0007] The invention aims in particular to provide a pressurized gas reservoir enabling the liner to be heated quickly and efficiently, while avoiding damage to the components of the pressurized gas reservoir.

[0008] To this end, the invention relates to a pressurized gas tank for a vehicle, comprising: - a liner made of plastic material, - a composite reinforcement structure wrapped around the liner, characterized in that the tank comprises: - an electric heating device configured to maintain the liner at a temperature above a predetermined threshold, the electric heating device comprising a temperature-self-regulating heating strip, the heating strip being disposed between the liner and an external surface of the composite reinforcement structure.

[0009] Such a pressurized gas reservoir allows the liner to be heated quickly and efficiently, while preventing damage to the tank components. Thus, thanks to the use of such a heating strip, heating is achieved rapidly and efficiently. Furthermore, the use of such a temperature-regulating heating strip ensures that the strip's temperature does not become too high at any point due to heating. This prevents damage to the tank components, and primarily to the liner, due to excessive localized heating.

[0010] Depending on other optional features of the tank, taken alone or in combination with combination:

[0011] - The liner is polyamide-based, preferably PA6 or PA66-based, preferably tiellement en PA6. Indeed, polyamide such as PA6 presents an excellent barrier effect to high-pressure gases.

[0012] - The heating strip is a positive temperature coefficient thermistor (PTC). Thus, the heating strip is self-regulating in temperature in a simple and economical way.

[0013] - The predetermined threshold is greater than -45°C, preferably equal to -40°C. Indeed, A liner made of plastic material is more fragile below such a temperature.

[0014] - The heating strip is temperature self-regulating such that its temperature The maximum temperature should be below 120°C, preferably below 100°C, preferably below 85°C, and even more preferably below 80°C. Indeed, the plastic material of the liner is likely to degrade above such a temperature.

[0015] - The tank is configured to store gas at a pressure of at least 350 bar, preferably at least 700 bar.

[0016] - The heating strip is arranged between the liner and the reinforcement structure composite. Thus, the positioning of the heating strip between the liner and the composite reinforcement structure reduces the vibrations experienced by the heating strip and limits the risk of the heating strip detaching.

[0017] - The tank includes a temperature sensor disposed between the liner and a external surface of the composite reinforcement structure, and preferably placed directly on the liner. Thus, the temperature of the liner can be measured, which allows the heating strip to start when the temperature is less than or equal to the predetermined threshold, preferably when the temperature measured by the temperature sensor is less than or equal to 35°C.

[0018] - The heating strip extends at an angle between 85° and 90° relative to a longitudinal axis of the tank. Thus, manufacturing is facilitated, due to the similar geometry to that of at least part of the composite reinforcement structure, namely the hoop-type layers.

[0019] - The heating strip is formed in a helix around the liner.

[0020] - The liner includes a groove configured to receive the heating strip. Thus, The manufacture of the reinforcement structure is facilitated, because the groove allows for a more regular external surface of the assembly formed by the liner and the heating strip, the heating strip not being very prominent or not protruding much outside the outermost radial surface of the liner.

[0021] - The heating strip is wound together with the reinforcing structure composite. Thus, manufacturing is optimized, due to the assembly of the strip The heated version does not require any specific assembly steps.

[0022] - The heating strip is wound directly onto the liner. Thus, the manufacturing is simplified, because the liner is already designed to support the winding of the reinforcement structure.

[0023] - The liner comprises a central cylindrical portion. Thus, the manufacture by in The rolling of the reinforcement structure around the liner is facilitated. For example, the cross-section of the central cylindrical portion is a circle or an ellipse.

[0024] - The heating strip is arranged radially between the liner and an external surface of the composite reinforcement structure.

[0025] - The heating strip has a width greater than its thickness, preferably at least 5 times higher, preferably at least 10 times higher.

[0026] - The heating strip has a thickness of less than 5 mm, preferably in less than 3 mm, preferably less than 1 mm, more preferably equal to 0.5 mm. A thin profile makes it easier to wind the heating strip.

[0027] - The heating strip includes a sheath formed of the same material as the liner. Thus, the cohesion between the liner, the heating strip and the composite reinforcement structure is improved.

[0028] - The reservoir includes a nozzle disposed on an end opening of the liner, the tip being metallic, preferably aluminum.

[0029] - The internal surface area of ​​the heating strip is at least 30%, preferably at less than 60% of the liner's external surface area. Thus, the heating surface is relatively large and allows for faster heating.

[0030] - The composite reinforcement structure comprises hoop-type layers - « hoop layers » in English - extending at an angle between 85° and 90° relative to a longitudinal axis of the reservoir and helical layers - « helical layers » in English - extending at an angle between 5° and 85° relative to a longitudinal axis of the reservoir.

[0031] - The heating strip extends at an angle between 5° and 90°, preferably between 85° and 90° relative to a longitudinal axis of the tank. Thus, the heating strip can be assembled onto the tank using methods similar to those used to manufacture the composite reinforcement structure. As a result, manufacturing is optimized.

[0032] - The reservoir includes smoothing means, the external surface of which is flush with the external surface of the heating band. This improves the tank's structural strength because the composite reinforcement structure is wound around a smoother surface. Indeed, for proper winding of the composite reinforcement structure, the surface to which the winding is applied must be smooth; otherwise, irregularities will occur at the connection point with the liner and / or the band. heating problems may occur.

[0033] - The tank includes heat transfer means configured for transfer heat from the heating strip to the liner.

[0034] - The heat transfer means are arranged between the liner and a surface external composite reinforcement structure.

[0035] - The smoothing means include or are constituted by the transfer means thermal. Thus, the manufacture of the tank is optimized, because the heat transfer means are integrated into the smoothing means or form the smoothing means.

[0036] - The heat transfer means are chosen from the group comprising a thermal paste strip, metallic strip, metallic film, metallic wire, and combinations thereof.

[0037] - The heating strip is prefabricated in one piece with smoothing means, in order to form a heating element. Thus, the manufacture of the tank is facilitated.

[0038] - The heating element includes heat transfer means, which are axially offset from the heating strip along a longitudinal axis of the tank. This provides heating over a large area of ​​the liner while limiting the width of the heating strip.

[0039] - The heating strip has a nominal heating power of at least 750W, preferably at least 1500W.

[0040] - The heating strip extends axially along a longitudinal axis of the reservoir.

[0041] - The heat transfer means extend at an angle between 5° and 90°, preferably between 85° and 90°, relative to a longitudinal axis of the tank. Thus, the heat transfer means can be placed on the tank using means similar to those used to manufacture the composite reinforcement structure.

[0042] - The heating strip is printed on the liner. Thus, the manufacture of the strip The heating system is particularly simple, and ensures that the heating is efficient, as the heating strip directly heats the liner due to its imprint on the liner.

[0043] The invention also relates to a vehicle comprising a tank as described above.

[0044] The invention also relates to a method for manufacturing a tank as described above, comprising the following successive steps: - step a): manufacture a liner from plastic material by molding, for example by rotomolding or by blow molding or by extrusion blow molding, - Step b): Wrap a heating strip around the liner, for example in a groove liner,

[0045] - step c): wrap a composite reinforcement structure around the liner and the strip heated.

[0046] According to an optional feature of the manufacturing process, step c) is carried out simultaneously with step b) when the heating strip is wound jointly with the composite reinforcement structure.

[0047] The invention also relates to a method for thermally regulating a tank as described above, comprising the following steps: - measurement of the liner temperature, preferably using a temperature sensor placed between the liner and an external surface of the composite reinforcement structure, more preferably placed directly on the liner, - supplying electrical power to the heating strip when the measured temperature is less than or equal to the sum of the predetermined threshold and a tolerance value, the tolerance value preferably being between 0°C and 5°C, more preferably equal to 5°C. Brief description of the figures

[0048] The invention will be better understood upon reading the following description, given solely by way of example and made with reference to the accompanying drawings in which:

[0049] [Fig-1] is a schematic view of a vehicle comprising a gas tank under pressure ;

[0050] [Fig.2] is a schematic view of a pressurized gas reservoir according to a first embodiment;

[0051] [Fig.3] is a schematic cross-sectional view of a detail of a pressurized gas tank according to a second embodiment;

[0052] [Fig.4] is a schematic cross-sectional view of a detail of a pressurized gas tank according to a third embodiment. Detailed description

[0053] In all figures, the same references refer to the same elements.

[0054] In this detailed description, the following are examples. The fact that the description refers to one or more embodiments does not mean that the features apply only to a single embodiment. Simple features from different embodiments can also be combined and / or interchanged to provide other embodiments.

[0055] Figure 1 schematically represents a vehicle 1, for example a motor vehicle, comprising a pressurized gas tank 3, in this example hydrogen. In this example, the vehicle 1 includes a fuel cell 5 supplied with hydrogen from the tank 3. The tank 3 is configured to store gas at a pressure of at least 350 bar, preferably at least 700 bar. Thus, tank 3 has an allowable storage pressure greater than 350 bar, preferably greater than 700 bar.

[0056] The tank 3, as shown in [Fig.2], comprises a liner 7, a composite reinforcement structure 9 and an electric heating device 11.

[0057] The liner 7 is made of plastic material. In this example, the liner 7 is made of polyamide, preferably PA6 or PA66, preferably PA6. The liner 7 comprises a cylindrical central portion 13. In this example, the liner 7 also comprises domed end portions 15. Thus, the liner 7 includes an end opening on each of the end portions 15, on which a nozzle 19 is disposed, the nozzle 19 being made of aluminum in this example. At least one nozzle 19 is connected to functional elements for distributing the gas out of the tank 3 through the nozzle 19, such as a solenoid valve.

[0058] The composite reinforcement structure 9 is wrapped around the liner 7. The composite reinforcement structure 9 comprises hoop layers extending at an angle between 85° and 90° with respect to a longitudinal axis X of the tank 3 and helical layers extending at an angle between 5° and 85° with respect to the longitudinal axis X of the tank 3.

[0059] The electric heating device 11 is configured to maintain the liner 7 at a temperature above a predetermined threshold. The predetermined threshold is above -45°C, preferably equal to -40°C. For this purpose, the electric heating device 11 comprises a temperature-self-regulating heating strip 21, the heating strip 21 being disposed between the liner 7 and an external surface 23 of the composite reinforcement structure 9.

[0060] The heating strip 21 is temperature-regulated such that its maximum temperature is below 120°C, preferably below 100°C, preferably below 85°C, and even more preferably below 80°C. For example, the heating strip 21 is a positive temperature coefficient (PTC) thermistor. Such a heating strip 21 consists, for example, of a layer of carbon-filled polymer, which is arranged between two copper or aluminum sheets. Furthermore, the heating strip 21 includes a sheath made of the same material as the liner 7. The heating strip 21 has a nominal heating power of at least 750W, preferably at least 1500W. The heating strip 21 is arranged radially between the liner 7 and the external surface 23 of the composite reinforcement structure 9. In this example, the heating strip 21 is arranged between the liner 7 and the composite reinforcement structure 9.The heating strip 21 has a width greater than its thickness, preferably at least . The heating strip 21 is 5 times thicker, preferably at least 10 times thicker. It has a thickness of less than 5 mm, preferably less than 3 mm, preferably less than 1 mm, and more preferably 0.5 mm. The internal surface area of ​​the heating strip is at least 30%, preferably at least 60%, of the external surface area of ​​the liner 7. In this example, the heating strip 21 extends at an angle between 5° and 90°, preferably between 85° and 90°, relative to the longitudinal axis X of the tank 3. Furthermore, in this example, the heating strip 21 is helical around the liner 7. According to an alternative embodiment not shown, the heating strip 21 extends axially along the longitudinal axis X of the tank 3.

[0061] Furthermore, the heating strip 21 is wound jointly with the composite reinforcement structure 9. In addition, in this example, the heating strip 21 is wound directly onto the liner 7. Alternatively, the heating strip 21 is printed onto the liner 7.

[0062] The tank 3 also includes a temperature sensor 25 disposed between the liner 7 and the external surface 23 of the composite reinforcement structure 9. In this example, the temperature sensor 25 is disposed directly on the liner 7.

[0063] According to a second embodiment of the reservoir 3', shown in [Fig. 3], this reservoir 3' differs from the reservoir 3 according to the first embodiment described above in that the reservoir 3' comprises smoothing means 27', the external surface 29' of which is flush with the external surface 31' of the heating strip 21'. In this example, the reservoir 3' also comprises heat transfer means 33' configured to transfer heat from the heating strip 21' to the liner 7'. The heat transfer means 33' are arranged between the liner 7' and an external surface 23' of the composite reinforcement structure 9'. The heat transfer means 33' are selected from the group comprising a thermal paste strip, a metal strip, a metal film, a metal wire, and combinations thereof.The heat transfer means 33' extend at an angle between 5° and 90°, preferably between 85° and 90°, relative to the longitudinal axis X of the reservoir 3'. In this example, the smoothing means 27' comprise or are formed by heat transfer means 33'. Furthermore, the heat transfer means 33' are axially offset relative to the heating strip 21' along the longitudinal axis X of the reservoir 3'. According to an alternative embodiment, the heating strip 21' is prefabricated as a single unit with the smoothing means 27', so as to form a heating element. The heating element thus comprises the heat transfer means 33', which are axially offset relative to the heating strip 21' along a longitudinal axis X of the reservoir 3'.

[0064] According to a third embodiment of the reservoir 3”, shown in [Fig. 4], this reservoir 3” differs from the reservoir 3 according to the first embodiment described above previously and the 3' tank according to the second embodiment described above in that the 7” liner includes a 35” groove configured to receive the 21” heating strip. Thus, the 21” heating strip is wound around the 7” liner in the 35” groove. According to an alternative not shown, the 35” groove is also configured to receive the smoothing means and / or the heat transfer means described above.

[0065] An example of a manufacturing process for a 3, 3', 3" tank as defined above is described below. Such a manufacturing process comprises the following successive steps:

[0066] - step a): manufacture a 7, 7', 7" liner from plastic material by molding, by for example by rotomolding or by blow molding or extrusion blow molding,

[0067] - step b): wrap a heating strip 21, 21', 21" onto the liner 7, 7', 7" by example in a 35” groove of the 7” liner

[0068] - step c): wrap a composite reinforcement structure 9, 9', 9" around the liner 7, 7', 7" and the heating strip 21, 21', 21".

[0069] For example, step c) is carried out simultaneously with step b) when the heating strip 21, 21', 21" is wound together with the composite reinforcement structure 9, 9', 9".

[0070] An example of a method for thermally regulating a 3, 3', 3" tank of the aforementioned type is described below. Such a thermally regulating method comprises the following steps:

[0071] - measurement of the temperature of the liner 7, 7', 7”, preferably by means of the sensor temperature 25,

[0072] - electrical power supply to the heating strip 21, 21', 21" when the measured temperature is less than or equal to the sum of the predetermined threshold and a tolerance value, the tolerance value preferably being between 0°C and 5°C, more preferably equal to 5°C.

[0073] The invention is not limited to the embodiments shown, and other embodiments will be obvious to those skilled in the art. In particular, it is possible to combine the embodiments with each other. List of references

[0074] 1: vehicle 3, 3', 3": reservoir 5: Fuel cell 7, 7', 7": liner 9, 9', 9": composite reinforcement structure 11: Electric heating device 13: central portion 15: end portion 19: tip 21, 21', 21": heating strip 23, 23', 23": external surface of the composite reinforcement structure 25: Temperature sensor 27': smoothing methods 29': external surface of the smoothing means 31': external surface of the heating strip 33': means of heat transfer 35”: groove X: longitudinal axis of the tank

Claims

Demands

1. A pressurized gas tank (3, 3', 3") for a vehicle (1), comprising: - a liner (7, 7', 7") made of plastic material, - a composite reinforcement structure (9, 9', 9") wrapped around the liner (7, 7', 7"), characterized in that the tank (3, 3', 3") comprises: - an electric heating device (11) configured to maintain the liner (7, 7', 7") at a temperature above a predetermined threshold, the electric heating device (11) comprising a temperature-self-regulating heating strip (21, 21', 21"), the heating strip (21, 21', 21") being disposed between the liner (7, 7', 7") and an external surface of the composite reinforcement structure (9, 9', 9"), and in that the heating strip (21, 21', 21") is a Positive temperature coefficient thermistor (PTC).

2. Tank (3, 3', 3") according to any one of the preceding claims, in which the heating strip (21, 21', 21") is disposed between the liner (7, 7', 7") and the composite reinforcement structure (9, 9',

3. ” )■ Tank (3, 3', 3”) according to any one of the preceding claims, which includes a temperature sensor (25) disposed between the liner (7, 7', 7”) and an external surface (23, 23', 23”) of the composite reinforcement structure (9, 9', 9”), and preferably disposed directly on the liner (7, 7', 7”).

4. Reservoir (3, 3', 3") according to any one of the preceding claims, in which the heating strip (21, 21', 21") extends at an angle between 85° and 90° with respect to a longitudinal axis X of the reservoir (3, 3', 3").

5. Tank (3, 3', 3") according to any one of the preceding claims, in which the heating strip (21, 21', 21") is formed in a helix around the liner (7, 7', 7").

6. Reservoir (3, 3', 3") according to any one of the preceding claims, in which the heating band (21, 21', 21") is wound jointly with the composite reinforcement structure (9, 9', 9").

7. Tank (3, 3', 3") according to any one of the preceding claims, in which the heating strip (21, 21', 21") is wound directly onto the liner (7, 7', 7").

8. Tank (3”) according to any one of the preceding claims, wherein the liner (7”) includes a groove (35”) configured to receive the heating strip (21”).

9. Vehicle (1) comprising a tank (3, 3', 3") according to any one of the preceding claims.

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