Method for producing a compressed gas tank for a motor vehicle

Abstract

Method for producing a compressed gas tank (1) for a motor vehicle, wherein a housing (2) of the compressed gas tank (1) is provided, which has an axially extending housing opening (4.1), a bundle (10) of helically wound heat-conducting elements (11), each of which has a through-channel (11.1, 11.2) for a coolant, is inserted with a first end (10.1) first through the housing opening (4.1) at least partially into the housing (2), wherein the bundle (10) is connected at the first end (10.1) in a rotationally secure manner to an engagement element (12), which is positively connected to an engagement region (5.1) of the housing (2) axially opposite the housing opening (4.1), and then at least one force is exerted on a second end (10.1).2) of the bundle (10), by means of which a torsional moment is exerted on the bundle (10), as a result of which the winding of the bundle (10) is reduced and the bundle (10) expands radially within the housing (2), wherein the heat-conducting elements (11) are connected to one another at the second end (10.2) by a head element (13), and an external thread (13.1) of this head element (13) is screwed into an internal thread (4.2) of the housing opening (4.1), wherein by rotating the second end (10.2) during screwing in, the winding of the bundle (10) is reduced and the bundle (10) is spread out.

Description

[0001] The invention relates to a method for producing a compressed gas tank for a motor vehicle.

[0002] Compressed gas tanks or pressure vessels are used in the automotive sector, for example, to store natural gas, LPG, or hydrogen for fuel cells. The compressed gas tank typically has a cylindrical central section, to which curved or domed end sections are connected. Typically, a compressed gas tank has an inner shell surrounded by an outer shell consisting of wound continuous fibers (rovings) in a polymer matrix. Fiber reinforcement is often essential for sufficient compressive strength. There are known compressed gas tanks made entirely of metal, as well as those made of metal and fiber-reinforced exclusively in the cylindrical central section.Other compressed gas tanks have a metal inner shell and are fiber-reinforced in both the middle section and the end sections; still others have an inner shell made of a polymer that is fiber-reinforced in the middle section and the end sections and has metal end pieces for a valve or closure. During refueling, the compressed gas tank heats up considerably, mainly due to the compression of the gas inside the tank (and possibly in a line leading to the tank). This can lead to the risk of exceeding a maximum tank temperature specified for safety reasons. To prevent this, either refueling must be carried out more slowly or the gas must be pre-cooled before refueling, which is energy-intensive. In some cases, refueling must be automatically interrupted for safety reasons if the maximum temperature is reached or exceeded.

[0003] US 2011 / 0 011 572 A1 discloses a heat exchanger for underwater use. It comprises a plurality of tube bundles of equal length, each of which comprises a plurality of tubes wound helically around a central axis. Each tube bundle is surrounded by a tube shell. Arranged along the central axis at both ends are end pieces, which are connected by a cylindrical outer wall. The end pieces have openings in which the tubes and the tube shells are accommodated on both sides.

[0004] CN 105 910 467 A discloses a horizontally arranged heat exchanger with a cylindrical outer shell in which a tube bundle is arranged. The tubes of the tube bundle are connected on both sides to end chambers, which have inlet and outlet connections for a first fluid. The outer shell, in turn, has inlet and outlet connections for a second fluid. The inlet connections are arranged on the top side, and the outlet connections are arranged on the bottom side. The tube bundle has a straight central tube running along a central axis, as well as a plurality of helically shaped outer tubes arranged around the central tube.

[0005] CN 203 550 678 U discloses a cooler with a housing in which a plurality of tubes are arranged, which are connected to an oil inlet and an oil outlet at opposite ends of the housing. The tubes are surrounded by a cylindrical outer shell having a water inlet and a water outlet. Several concentrically arranged groups of tubes are provided, with the tubes of a group each being the same distance from a central axis of the housing. Furthermore, it is provided that the tubes are wound helically, with the winding of adjacent groups of tubes being opposite to each other.

[0006] US Pat. No. 9,964,077 B2 discloses a heat exchanger comprising a housing enclosing at least two bundles of tubes, each connected to a header on either side. Each bundle comprises a plurality of tubes wound helically around a common axis. The helical structure allows for better absorption of heat-induced expansion of the individual tubes without resulting in excessive axial force on the headers.

[0007] In view of the state of the art shown, the efficient design of the filling process for a motor vehicle's compressed gas tank still offers room for improvement.

[0008] US 9 957 103 B2 discloses a heat transfer unit for a prefabricated container. This comprises a central rod and a plurality of peripheral rods surrounding the central rod and movable between a first folded position and a second bent position. In the second bent position, a center point of each of the peripheral rods is spaced from the central rod relative to the first position, and each of the plurality of peripheral rods extends helically around a longitudinal axis. A heat transfer element is connected to one of the plurality of peripheral rods. The peripheral rods can also be configured for heat exchange. The container has an opening through which the heat transfer unit can be inserted.

[0009] DD 273 496 A1 discloses a tube bundle heat exchanger for vessels, comprising flexible heat transfer tubes that are either located between two tube plates with a flow distributor arranged thereon or that are attached only to one tube plate with a flow distributor arranged thereon, and each have a free end. Due to the introduction of pressure and / or torsional forces into the tube plate or into a part coupled thereto, the flexible heat transfer tubes have an enlarged envelope diameter and a curved tube center axis after insertion through an opening in a vessel nozzle in the vessel.

[0010] The invention is based on the object of enabling efficient filling of a compressed gas tank of a motor vehicle.

[0011] According to the invention, the object is achieved by a method having the features of claim 1.

[0012] A method for producing a compressed gas tank for a motor vehicle is presented, wherein a housing of the compressed gas tank is provided which has an axially extending housing opening, wherein a bundle of helically wound heat-conducting elements, each of which has a through-channel for a coolant, is inserted at least partially into the housing with a first end leading through the housing opening, wherein the bundle is connected at the first end in a rotationally secure manner to an engagement element which is positively connected to an engagement region of the housing axially opposite the housing opening, and then at least one force is exerted on a second end of the bundle, by which a torsional moment is exerted on the bundle, whereby the winding of the bundle is reduced and the bundle expands radially within the housing, wherein the heat-conducting elements are connected to one another at the second end by a head element,and an external thread of this head element is screwed into an internal thread of the housing opening, whereby a rotation of the second end during screwing in simultaneously reduces the winding of the bundle and spreads the bundle.

[0013] The subclaims relate to advantageous embodiments of the invention.

[0014] It should be noted that the features and measures listed individually in the following description can be combined with one another in any technically reasonable manner and demonstrate further embodiments of the invention. The description further characterizes and specifies the invention, particularly in conjunction with the figures.

[0015] The invention provides a method for producing a compressed gas tank for a motor vehicle. The motor vehicle can be, for example, a car or a truck. The compressed gas tank can also be referred to as a liquid gas tank and is normally used to hold a pressurized gas that is used to power the motor vehicle, e.g. hydrogen for a fuel cell or natural gas (compressed natural gas, CNG), dimethyl ether (DME) or even autogas (liquefied petroleum gas, LPG, normally a mixture of butane and propane) for a suitably equipped internal combustion engine. Due to the high pressure, the gas may be completely or partially in a liquefied state within the compressed gas tank during operation. Nevertheless, for the sake of simplicity, we will refer to the term "gas" here, as this also corresponds to the state of matter under normal conditions in these cases.

[0016] According to the method, a housing of the compressed gas tank is provided which has an axially extending housing opening. Within the housing, an interior space is naturally formed which, in the operating state, serves to accommodate the pressurized gas. In this context, the "axial direction" is defined as the direction in which the housing opening extends and passes through the housing wall. However, the axial direction can also correspond to a housing axis along which the housing extends and to which it is at least partially symmetrical. Various options exist with regard to the further design of the housing. For example, the housing could have a tangentially circumferential central section and two end sections connected to it at the axial ends.The end sections can be prefabricated separately from the middle section, so that the housing is composed of at least three parts, which are generally surrounded by an outer shell as described below. With regard to the axial direction, the middle section is designed to be tangentially circumferential, i.e. it surrounds the housing axis like a cylindrical shell. Normally the cross-section of the middle section is circular and at least approximately constant along the axial direction. At each of the axially opposite ends of the middle section, an end section is connected to the middle section, wherein the said sections can also be manufactured integrally with one another. Alternatively, the end sections can be manufactured separately, in which case they can also be referred to as end pieces. The shape of the respective end section can be convex (or possibly concave) at least in sections.In the embodiment described here, the housing opening is formed in one of the end sections or end pieces and can in particular be formed symmetrically to the housing axis. With regard to the materials of the housing, there are no restrictions within the scope of the invention. Normally, the end pieces are made of metal, e.g. aluminum. The middle section can, for example, be made of a polymer or also of a metal. The housing parts described here can in particular form an inner jacket or liner of the housing, which is completely or partially wound on the outside with bundles (so-called rovings) of continuous fibers, e.g. carbon fibers, glass fibers, aramid fibers, etc. or mixtures of different fibers, which in turn are bound in a polymer matrix.

[0017] This fiber reinforcement can, in particular, improve the pressure resistance of the tank. Pressure gas tanks are typically manufactured in one of the following types: all-metal tanks, metal tanks reinforced with fiber laminate in the center section, metal tanks completely reinforced with fiber laminate, or tanks with a polymer center section and metal end pieces, and completely reinforced with fiber laminate.

[0018] As already mentioned above, a bundle of heat-conducting elements is inserted at least partially into the housing with a first end first through the housing opening. In their fully assembled state, the heat-conducting elements serve to dissipate heat from the interior of the housing. This is particularly advantageous when filling the compressed gas tank, during which it could heat up considerably, mainly due to the compression of the gas. However, since at least part of the heat generated by compression can be transferred to the heat-conducting elements and dissipated via them, the heating of the compressed gas tank is limited, making it easier to maintain a maximum tank temperature specified for safety reasons. This, in turn, has the advantage that refueling can be carried out more quickly without the need to pre-cool the gas.

[0019] To optimally fulfill their function, heat-conducting elements are normally made of metal, e.g., stainless steel. They can optionally have a surface coating, although this should be selected so that it does not significantly limit thermal conductivity. In general, any heat-conducting element can be described as elongated, meaning that along a direction that can be referred to as the longitudinal direction or direction of extension, it has an extension that is normally at least five times or at least ten times the extension transverse to the direction of extension. The outer cross-section of a heat-conducting element can be designed in different ways, e.g., polygonal, rectangular, oval, or, in particular, circular. Normally, the outer cross-section is constant along the entire length of the heat-conducting element, but it could also vary.The bundle has a plurality of heat-conducting elements, the number of which can be, for example, between 4 and 20 or between 6 and 15. Within the bundle, each heat-conducting element is normally arranged adjacent to at least one other heat-conducting element, typically to at least two other heat-conducting elements. In particular, it can touch at least one other heat-conducting element, at least in part. The bundle has a first end and is inserted at least partially into the housing through the housing opening with this first end first (or foremost). The direction of movement during insertion can correspond at least approximately to the axial direction, for example, it can deviate from the axial direction by less than 20°. As will be explained below, the bundle is preferably only partially inserted, for example.It can be inserted at 50% to 80% of its length, while the remaining 20% to 50% initially remains outside the housing. The bundle can be inserted manually, but is preferably inserted automatically.

[0020] After at least partial insertion, as already mentioned above, at least one force is exerted on a second end of the bundle, causing the bundle to expand radially within the housing. The second end of the bundle is arranged opposite the aforementioned first end, i.e., it is arranged at the rear with respect to the direction of movement of the insertion. Typically, it is still arranged outside the housing after the (partial) insertion of the bundle. At least one force is exerted on the second end. The force can be exerted directly or via at least one intermediate element. Although the at least one force could, in principle, be exerted manually, it is preferred for reasons of precision that it be exerted automatically. In particular, it can also be a force couple that corresponds to a torque. Strictly speaking, the at least one force is exerted on the second end relative to the first end. Ie.At the same time, a counterforce acts on the first end, preventing the bundle from simply moving as a whole due to the action of the said force. The exertion of at least one force causes the bundle to expand radially within the housing. This means that if one considers the expansion of the entire bundle transverse to the axial direction, namely in the radial direction, this expansion increases as a result of the exertion of at least one force. One could also say that the individual heat-conducting elements of the bundle move away from one another, so that the bundle as a whole expands or is spread out. The expansion or spreading does not normally occur along the entire length of the bundle, but only in certain areas. In particular, it does not have to occur evenly in all areas of the bundle.

[0021] In any case, the expansion of the bundle improves the effectiveness of the cooling achieved by the heat-conducting elements. The heat-conducting elements of the bundle can initially be inserted through the housing opening in a relatively compact form and then spread out as described, allowing them to cool a larger volume of the interior. For the sake of simplicity, it can be assumed in the model that each heat-conducting element contributes to cooling a certain area near the heat-conducting element. In the compact form in which the bundle is inserted, the corresponding areas of the heat-conducting elements can overlap, which can impair cooling. In addition, there may initially be no or only minimal gaps between the heat-conducting elements, so that the gas to be cooled cannot or only with difficulty get between the heat-conducting elements.After expansion and spreading, there are usually sufficient gaps so that each heat conducting element contributes to the heat exchange with its entire surface.

[0022] The course of the individual heat-conducting elements within the bundle can vary. For example, the heat-conducting elements could be arranged straight during insertion. According to a preferred embodiment, a bundle of helically wound heat-conducting elements is inserted. This means that at least during insertion, the heat-conducting elements within the bundle are wound helically, i.e., in the manner of a screw line. Viewed individually, each heat-conducting element runs helically. Viewed as a whole, one can say that the heat-conducting elements are wound around one another or at least approximately around a common bundle axis. All heat-conducting elements of the bundle are wound in the same direction or in the same sense.

[0023] In principle, it would be conceivable for an axial force to be exerted on the second end, compressing the bundle in the axial direction while simultaneously expanding it in the radial direction. This would be possible regardless of the path of the heat-conducting elements, i.e., they could be straight, helically wound, or shaped in some other way. In this case, however, the deformation of the individual heat-conducting elements may be difficult to control. In addition, a considerable axial force may be necessary, which in turn must be compensated for by a corresponding counterforce on the first end. If the first end passes the force on to the housing, for example, there could be a risk of damage to the housing. As mentioned above, the at least one force exerts a torsional moment on the bundle, reducing the twist of the bundle. One could also say that the torsional moment counteracts the twist of the bundle.Of course, at least one force couple is necessary for a torsional moment. The torsional moment causes the second end to rotate relative to the first end. The reduction in winding is usually accompanied by a shortening of the bundle, i.e., the distance between the first and second ends decreases. In particular, the second end can initially be located outside the housing, while after the expansion has ended, it is located inside the housing, e.g., inside the housing opening.

[0024] As already explained, the at least one force or torque acting on the second end must be compensated by an opposite force or torque on the first end in order to prevent twisting or displacement of the entire bundle. The housing usually has a second housing opening opposite the aforementioned housing opening. In principle, it would be possible to grip the first end from the outside through this second housing opening and thus stabilize it while the force is exerted on the second end. However, this procedure is generally complicated. It is therefore preferred that the first end of the bundle is connected in a torque-transmitting manner to an engagement region of the housing axially opposite the housing opening, after which the torsional moment is exerted.The connection is at least torque-transmitting and can, in particular, be rotationally fixed, so that the first end cannot rotate relative to the housing. Torque transmission can be achieved, for example, by a frictional connection, possibly by a material connection, and / or, in particular, by a positive connection.

[0025] As already mentioned above, the bundle is connected at the first end in a rotationally secure manner to an engagement element which is brought into positive engagement with the engagement region. The first engagement element can be connected to the heat-conducting elements of the bundle in a positive, non-positive and / or materially bonded manner. For example, it can have continuous recesses or recesses open towards the second end, in which the heat-conducting elements are received at the ends. On an opposite side, which faces the engagement region, the engagement element has structures which enable a positive connection, in particular a positive connection in the tangential direction. These can be, for example, axial projections and / or recesses. These correspond to structures of an engagement region. For example, the first engagement element could have a projection which can be inserted into a recess in the engagement region or vice versa.The positive locking prevents the first end from twisting relative to the engagement area. It would also be conceivable for the engagement element to have an external thread that is screwed into an internal thread formed in the engagement area.

[0026] As already explained above, the bundle can be inserted through the housing opening in a compact form and then expanded radially, enabling more effective, more uniform cooling of the interior of the housing. In particular, during expansion, the radial expansion of the bundle can increase by at least 100%, at least in some areas, and possibly even by at least 200%. For example, the bundle could easily be guided through an end opening with an outer diameter of less than 5 cm, and then expanded to an outer diameter of 10 cm, 15 cm, or more.

[0027] Preferably, the expansion is based on at least predominantly elastic deformation of the heat-conducting elements. The same applies to the reduction in the coiling of the bundle. Thus, there is no or at most negligible plastic deformation of the heat-conducting elements. Such plastic deformation, which would be associated, for example, with at least a local exceeding of the yield point, could adversely affect the durability of the heat-conducting elements. This, combined with larger temperature differences, could lead to cracks in the heat-conducting elements. Furthermore, plastic deformation carries the risk of reducing the cross-sections of the through-channels and impeding flow. Whether the range of elastic deformation is maintained can be verified based on the specific deformation and the known material properties of the heat-conducting elements.

[0028] The heat conducting elements can be solid, for example, as metal rods that dissipate heat from the interior of the compressed gas tank solely through thermal conduction. At least one heat conducting element has a through-channel for a coolant, which applies to all heat conducting elements. Each heat conducting element has a through-channel that is continuous along the entire length of the heat conducting element. The heat conducting element can therefore be described as hollow or at least tubular in the broadest sense. In this case, one can also speak of a heat conducting tube. The cross-section of the through-channel can be designed in different ways, for example, polygonal, rectangular, oval, or, in particular, circular. Normally, the cross-section is constant along the entire length of the heat conducting element, but it could also vary.It would be conceivable for a heat conducting element to have a plurality of through-channels, but normally each heat conducting element has exactly one through-channel.

[0029] The respective through-channel is or will be connected at least indirectly to two coolant connections, which can each be arranged at one of the end sections. The connection is generally established before the bundle is inserted into the housing. The two coolant connections form an inlet and an outlet for the coolant. Naturally, one end of the through-channel is connected (directly or indirectly) to one coolant connection, while the other end is connected to the other coolant connection. The coolant connections can be connected to a coolant circuit of the motor vehicle when the compressed gas tank is installed.In other words, when installed, the compressed gas tank is integrated into the coolant circuit, with the coolant flowing in through one of the coolant connections (which can also be referred to as the inlet coolant connection) and flowing out again through the other (which can also be referred to as the outlet coolant connection). Due to the described connection of the through-channel to the coolant connections, the coolant is also guided through the through-channel. In particular, it can be provided that the through-channels have a group of first through-channels and a group of second through-channels, with the first through-channels being arranged upstream of the second through-channels. The first through-channels are thus connected via the second through-channels (and, if applicable,The first through-channels are connected to the outlet coolant connection via additional lines or channels, while the second through-channels are connected to the inlet coolant connection via the first through-channels (and possibly additional lines or channels). As an alternative to a coolant circuit of the motor vehicle, an at least partially external coolant circuit could also be used, e.g., a coolant circuit of a refueling station for the compressed gas tank.

[0030] Since the through-channel is formed inside the heat-conducting element, which in turn runs through the interior of the compressed gas tank, heat exchange can take place between the coolant in the through-channel and the gas in the interior of the compressed gas tank. In this case, the heat is transported not only by conduction, but above all by convection, i.e. by the coolant flow in the through-channel. This is generally much more effective than heat transport by conduction alone. The coolant can be a conventional liquid automotive coolant, e.g., a water-glycol mixture. This can also be used to cool or temperature-control other vehicle components. The heat transferred from the compressed gas to the coolant can be dissipated elsewhere to the outside of the vehicle via a radiator, or alternatively, it can be used to heat the vehicle interior.

[0031] As already mentioned above, the heat-conducting elements are connected to one another at the second end by a head element, and an external thread of this head element is screwed into an internal thread of the housing opening. This means that the housing opening has an internal thread that interacts with an external thread formed on the head element. The head element, like the heat-conducting elements, can be made of metal and, for example, have recesses in which the ends of the heat-conducting elements are received in a form-fitting manner. By screwing the head element into the housing opening, the second end is secured to the housing. This naturally also involves a rotation of the second end, which simultaneously reduces the winding of the bundle and allows the bundle to be spread open. Both coolant connections can be arranged on the head element, while at least one deflection channel is formed on the engagement element.Each diverting channel connects at least one first through-channel to at least one second through-channel and may be U-shaped. A first collecting channel connected to the inlet coolant port and a second collecting channel connected to the outlet coolant port may be formed in the head element. The first collecting channel may be connected to the first through-channels via first branch channels, while the second collecting channel may be connected to the second through-channels via second branch channels. Each of the collecting channels may be annular.

[0032] The head element can in turn have an axial through-opening into which a valve or a closure element is introduced and secured. The through-opening can be centered in particular with respect to the housing axis and the ends of the heat-conducting elements can be arranged (radially spaced) around the through-opening. Likewise, the through-opening is normally arranged concentrically to the above-mentioned housing opening. A valve can be introduced into the through-opening and, for example, screwed in, which valve can then be used to fill the compressed gas tank. This means that in this case the compressed gas tank is filled from the side of the (first) housing opening. Alternatively, it can be provided to fill the compressed gas tank from the opposite side, in which case a corresponding valve is arranged there. The (first) housing opening can then be closed by a closure element (end plug), which can also be, for example,can be secured by screwing in.

[0033] Further advantageous details and effects of the invention are explained in more detail below with reference to exemplary embodiments shown in the figures. Fig. 1-4 a sectional view of a compressed gas tank during various phases of a method according to the invention; Fig. 5-7 a detailed view of a bundle of heat pipes during various phases of the method according to the invention; Fig. 8 a perspective view of the bundle with a head element; Fig. 9 is a partial sectional view of a part of the bundle with the head element of Fig. 8; Fig. 10 a sectional view along the line XX in Fig. 9; and Fig. 11 a partial sectional view of a part of the bundle with an engagement element.

[0034] In the different figures, identical parts are always provided with the same reference symbols, which is why they are usually only described once.

[0035] Fig. 1 shows a sectional view of a compressed gas tank 1 for a motor vehicle, which can be used, for example, in a passenger car, during a first phase of a method according to the invention. The sectional plane in Fig. 1 runs parallel to a housing axis A, which corresponds to an axial direction. The housing axis A forms an axis of symmetry of the compressed gas tank 1. This has a housing 2 with a cylindrical middle section 3, to which a first end section 4 and a second end section 5 are axially connected. The representation of the housing 2 is greatly simplified here. Normally, this has an inner jacket made of plastic and / or metal, which is surrounded by an outer jacket consisting of wound rovings (continuous fibers) in a polymer matrix. An axially running housing opening 4.1 is formed at the first end section 4 in the region of the housing axis A. An engagement region 5.1 is formed in the second end section 5, the function of which is explained below.

[0036] Furthermore, in Fig. 1 shows a bundle 10 of coolant tubes 11 that are wound helically around one another. In the present example, the coolant tubes 11 are made of stainless steel. Each coolant tube 11 has a through-channel 11.1, 11.2, wherein a group of first through-channels 11.1 and a group of second through-channels 11.2 can be functionally distinguished, which will be explained below. At a first end 10.1, the coolant tubes 11 are connected to one another by an engagement element 12 that has an engagement structure 12.1 designed like a projection. This is complementary to an engagement structure 5.2 of a second engagement element 5.1 formed in the second end section 5. The ends of each coolant tube 11 can be received and, for example, screwed into recesses (not shown here) of the respective engagement element 12.The coolant tubes 11 could therefore first be screwed into the engagement element 12 and then twisted before being inserted into the compressed gas tank 1, thus achieving the helical configuration shown. According to the invention, the coolant tubes 11, which wind around each other helically, are held in a rotationally fixed manner by the engagement element 12, whereby a non-positive, materially bonded, or positive connection is contemplated. For example, the engagement element 12 can be designed as a sleeve and can comprehensively hold the bundle on the outside in a rotationally fixed manner, whereby the engagement structure 12.1 is arranged at a closed end of the engagement element 12. As shown in . Fig. 11, the engagement element 12 has a plurality of U-shaped deflection channels 12.2, each of which connects a first through-channel 11.1 with a second through-channel 11.2. At a second end 10.2, the coolant tubes 11 are connected by a head element 13, which in the enlarged illustrations of Fig. 8-10 can be seen better. The head element 13 is generally ring-shaped and has an external thread 13.1 and an internal thread 13.3 in a through-opening 13.2. Furthermore, a plurality of first branch channels 13.4 are formed, each of which is connected to a first through-channel 11.1 of one of the coolant tubes 11, and a plurality of second branch channels 13.5, each of which is connected to a second through-channel 11.2. The first branch channels 13.4 are connected to an inlet coolant connection 13.8 via an annular first collecting channel 13.6, while the second branch channels 13.5 are connected to an outlet coolant connection 13.9 via a second collecting channel 13.7, which is also annular. Both coolant connections 13.8, 13.9 are arranged on the head element 13.

[0037] In Fig. 1, the bundle 10 is partially inserted into an interior space 2.1 of the housing 2 with the first end 10.1 leading through a continuous housing opening 4.1 at the first end region 4 in the axial direction. The direction of movement during insertion corresponds at least approximately to the axial direction.

[0038] In Fig. 2, the bundle 10 is inserted so far that the first engagement element 5.2 engages the second engagement element 12 in a form-fitting manner, thereby preventing rotation of the engagement element 12 relative to the housing 2. The length of the bundle 10 is dimensioned such that a part of it, with the head element 13, is still arranged outside the housing 2. In the further course, a torque (corresponding to a force couple) is exerted on the second end 10.2, which leads to a torsional moment acting on the bundle 10. This condition is also shown in Fig. 5, where only a part of the bundle 10 is visible.

[0039] As the process continues, the applied torque causes the coiling of the bundle 10 to decrease, while simultaneously reducing its length in the axial direction. Thus, the radial dimension of the bundle 10 (its outer radius) within the compressed gas tank 1 increases, while the head element 13 is moved closer to the housing opening 4.1. This is shown in Fig. 3 and in Fig. 6 shown.

[0040] The described process continues until, as in Fig. 4 and Fig. 7, the bundle 10 is spread out to such an extent that its radial dimension has increased by more than 200% compared to the original state. It therefore fills the interior space 2.1 of the housing 2 considerably better than in the original state according to Fig.2. In addition, clear gaps between the individual heat pipes 11 are visible. The entire expansion of the bundle 10 occurs through elastic deformation of the individual heat pipes 11. Finally, the external thread 13.1 of the head element 13 is screwed into an internal thread 4.2 of the housing opening 4.1. The direction of rotation for screwing in is expediently selected so that the bundle expands further. In addition, a valve 14, shown here in a highly schematic manner, can be screwed into the internal thread 13.3 of the through-opening 13.2. Via the valve 14, the interior 2.1 of the housing 2 can be filled with a pressurized gas (e.g., hydrogen, natural gas, DME, or LPG), which is used to power the motor vehicle.

[0041] When installed, the through-channels 11.1, 11.2 of the coolant pipes 11 can be connected to a coolant circuit of the motor vehicle, which carries a liquid coolant (e.g., a water-glycol mixture) and serves to control the temperature, i.e., cool and / or heat, of various vehicle components or areas. More specifically, the inlet coolant connection 13.8 is connected to a supply coolant line (not shown), while the outlet coolant connection 13.9 is connected to a discharge coolant line. In this way, coolant can flow into the first through-channels 11.1 via the inlet coolant connection 13.8, the first collecting channel 13.6, and the first branch channels 13.4. From there, the coolant flows via the deflection channels 12.2 into the second through channels 11.2, and further via the second branch channels 13.5 and the second collecting channel 13.7 to the outlet coolant connection 13.9.From there, it flows into the coolant outlet line. When the motor vehicle is refueled, liquefied gas is filled from an external tank via a tank line and valve 14 into the compressed gas tank 1. As it flows into the compressed gas tank 1, the gas flows through the spaces between the coolant pipes 11 and comes into contact with the coolant pipes 11 over a relatively large area. This results in heat exchange between the gas, which heats up during filling, and the coolant in the passages 11.1, 11.2. The heating of the gas is limited by the heat exchange with the coolant via the wall of the respective coolant pipe 11. This prevents the temperature of the gas or the compressed gas tank 1 from exceeding a threshold value specified for safety reasons, even during relatively rapid refueling. External pre-cooling of the gas is not necessary for this.The heat absorbed by the coolant is dissipated via the coolant circuit and can, for example, be transferred to the vehicle interior or the vehicle's surroundings via a heat exchanger. As an alternative to the vehicle's cooling circuit, a connection to a (partially) external cooling circuit associated with the refueling station where the compressed gas tank 1 is refueled would also be conceivable. List of reference symbols: 1 compressed gas tank 2 housings 2.1 Interior 3 Middle section 4, 5 final section 4.1 Housing opening 4.2, 13.3 internal thread 5.1 Intervention area 5.2, 12.1 Intervention structure 10 bundles 10.1 first end 10.2 second end 11 Heat conduction element, heat conduction pipe, coolant pipe 11.1, 11.2 Through channel 12 engagement element 12.2 Deflection channel 13 Head element 13.1 External thread 13.2 Passage opening 13.4, 13.5 branch channel 13.6, 13.7 Collecting channel 13.8 Inlet coolant connection 13.9 Outlet coolant connection A Housing axis

Claims

[1] Method for producing a compressed gas tank (1) for a motor vehicle, wherein a housing (2) of the compressed gas tank (1) is provided, which has an axially extending housing opening (4.1), a bundle (10) of helically wound heat-conducting elements (11), each of which has a through-channel (11.1, 11.2) for a coolant, is introduced with a first end (10.1) first through the housing opening (4.1) at least partially into the housing (2), wherein the bundle (10) is connected at the first end (10.1) in a rotationally secure manner to an engagement element (12), which is positively connected to an engagement region (5.1) of the housing (2) axially opposite the housing opening (4.1), and then at least one force is exerted on a second end (10.1).2) of the bundle (10), by means of which a torsional moment is exerted on the bundle (10), as a result of which the winding of the bundle (10) is reduced and the bundle (10) expands radially within the housing (2), wherein the heat-conducting elements (11) are connected to one another at the second end (10.2) by a head element (13), and an external thread (13.1) of this head element (13) is screwed into an internal thread (4.2) of the housing opening (4.1), wherein by rotating the second end (10.2) during screwing in, the winding of the bundle (10) is reduced and the bundle (10) is spread out at the same time. [2] Method according to claim 1, characterized by that the expansion is based on an at least predominantly elastic deformation of the heat-conducting elements (11). [3] Method according to one of the preceding claims, characterized bythat the head element (13) has an axial through-opening (13.2) into which a valve (14) or a closure element is introduced and secured therein.

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