Gaseous permeate conduit reinforcement

Abstract

A pressure vessel includes a polymeric liner and a carbon fiber reinforced polymer (CFRP) laminate surrounding a circumference of the polymeric liner. The CFRP laminate includes an uncoated fiber tow and a permeate conduit wrapped or braided around the polymeric liner and coated with a resin. The uncoated fiber tow is impregnated with a cured resin. The permeate conduit includes a polymer-coated fiber tow which has been coated with a polymer that is impermeable to a liquid resin such that the polymer-coated fiber tow lacks the cured resin between the polymer coating and an interior of the polymer-coated fiber tow.

Description

GASEOUS PERMEATE CONDUIT REINFORCEMENTCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Application 63 / 650,293 filed on May 21, 2024, the disclosure of which is hereby incorporated by reference in its entirety.FIELD OF THE INVENTION

[0002] The present invention relates to type IV pressure vessels for storing fluid and / or gas under pressure. More specifically, the present invention relates to a type IV pressure vessel comprising a carbon fiber or composite wound and / or braided over a polymeric liner to form a composite shell structure having a gaseous permeate conduit reinforcement.DESCRIPTION OF RELATED ART

[0003] Type IV pressure vessels for storage of compressed gas comprising polymeric liners and fiber reinforced composite shell structures have been used as reliable, highly efficient vessels. Polymeric liners are more susceptible to permeation of gases than metallic tanks and metallic liners. Because of permeation, gas migrates through the polymeric liner from high pressure areas to low pressure areas. This migration may cause accumulation of gaseous permeate in a gap between the polymeric liner and the composite shell structure. Further, the gaseous permeate reduces the amount of fluid and / or gas stored under pressure in the pressure vessel.

[0004] However, accumulation of gas in between the polymeric liner and the composite shell structure can result in induced buckling of the polymeric liner inward as the pressure between the polymeric liner and the composite shell exceeds the internal pressure of the pressure vessel when the pressure vessel is depressurized. In the event of a rapid discharge of the pressure vessel, the gaseous permeate saturated throughout the polymeric liner may cause the polymeric liner to collapse. In addition, the trapped gaseous permeate between the polymeric liner and the composite shell as the pressure vessel is repressurized can prevent a proper fill or be pushed out of the pressure vessel structure, sometimes referred to as a "dynamic gas release".

[0005] Therefore, it is desirable to reduce the accumulation of gaseous permeate between the polymeric liner and the composite shell structure. Further, it is desirable to minimize the accumulation of gaseous permeate in the polymeric liner and in the composite shell in order toreduce the potential for the collapse of the polymeric liner during rapid defueling events and to prevent formation of blisters in the polymeric liner. It is also desirable to reclaim the gaseous permeate and resupply the gaseous permeate to the pressure vessel in order to reuse the gaseous permeate. Further, it is desirable to increase the storage capacity of the pressure vessel by minimizing losses of stored capacity7due to the migration of the gaseous permeate out of the pressure vessel.SUMMARY OF THE INVENTION

[0006] According to one embodiment, there is provided a pressure vessel which includes a permeate conduit. The pressure vessel has a polymeric liner and a carbon fiber reinforced polymer (CFRP) laminate. The polymeric liner has a liner wall, an internal cavity, and a first exterior opening. The liner wall has a tubular shape which extends circumferentially around the internal cavity and the first exterior opening extends through the liner wall to the internal cavity. The CFRP laminate surrounds a circumference of the polymeric liner. Further, the CFRP laminate includes an uncoated fiber tow and the permeate conduit wrapped or braided around the polymeric liner and coated with a resin. The uncoated fiber tow is impregnated with a cured resin. The permeate conduit includes a polymer-coated fiber tow which has been coated with a polymer that is impermeable to a liquid resin. The polymer-coated fiber tow lacks the cured resin between the polymer coating and an interior of the polymer-coated fiber tow.

[0007] According to another embodiment, there is provided a pressure vessel which includes a plurality of permeate conduits. The pressure vessel also includes a polymeric liner comprising a liner wall, an internal cavity, and a first exterior opening. The liner wall has a generally tubular shape which extends circumferentially around the internal cavity and the first exterior opening extends through the liner wall to the internal cavity. The pressure vessel also includes a carbon fiber reinforced polymer (CFRP) laminate surrounding a circumference of the polymeric liner. The CFRP laminate includes the plurality of permeate conduits wrapped or braided around the polymeric liner and coated with a resin. Each permeate conduit of the plurality of permeate conduits includes a polymer-coated fiber tow which has been coated with a polymer that is impermeable to liquid resin. Further, the polymer-coated fiber tow lacks the cured resin between the polymer coating and an interior of the polymer-coated fiber tow.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

[0009] Figure l is a perspective view of a pressure vessel having a permeate conduit, according to one embodiment of the present invention;

[0010] Figure 2 is a partial cross-sectional side view of a portion of the pressure vessel of Figure 1;

[0011] Figure 3 is a side view of a liner assembly, according to one embodiment of the present invention;

[0012] Figure 4 is an enlarged side view of portion 4 of the liner assembly of Figure 3;

[0013] Figure 5 is a cross-sectional side view of another portion of the pressure vessel of Figure 1;

[0014] Figure 6 shows an enlarged perspective view of portion 6 of the liner assembly of Figure 4;

[0015] Figure 7 is a cross-sectional view of an uncoated fiber tow, according to one embodiment of the present invention;

[0016] Figure 8 is a cross-sectional view of a polymer-coated fiber tow, according to one embodiment of the present invention;

[0017] Figure 9 is an enlarged cross-sectional view of portion 9 of the pressure vessel of Figure 2;

[0018] Figure 10 is a side view of the liner assembly of Figure 3. illustrating a braiding process;

[0019] Figure 11 is a perspective view of a liner assembly, according to a second embodiment of the present invention;

[0020] Figure 12 is a perspective view of a liner assembly, according to a third embodiment of the present invention;

[0021] Figure 13 is a perspective view of a liner assembly, according to a fourth embodiment of the present invention;

[0022] Figure 14 is an enlarged view of portion 14 of the liner assembly of Figure 13; and

[0023] Figure 15 is an enlarged view of portion 15 of the liner assembly of Figure 14.DETAILED DESCRIPTION OF THE INVENTION

[0024] Figures 1-15 illustrate a pressure vessel 10 having a permeate conduit 12. according to embodiments described herein. Directional references employed or shown in the description, figures or claims, such as top, bottom, upper, lower, upward, downward, lengthwise, widthwise, left, right, and the like, are relative terms employed for ease of description and are not intended to limit the scope of the invention in any respect. Referring to the Figures, like numerals indicate like or corresponding parts throughout the several views.

[0025] Referring to Figures 1 -5, the exemplary pressure vessel 10 is a ty pe IV pressure vessel, alternatively described as a conformable pressure vessel, a pressure tank, and the like, for storing a fluid and / or a gas under pressure. The pressure vessel 10 comprises a first tank end 14 opposing a second tank end 16, a plurality of chamber tanks 18, a plurality of cuff portions 20, and a plurality of tank connectors 22. Each chamber tank 18 is fluidically connected by a cuff portion 20 to an adjacent one of the tank connectors 22. Further, one chamber tank 18 is fluidically connected to the first tank end 14 and another chamber tank 18 is fluidically connected to the second tank end 16. It will be appreciated that the pressure vessel 10 might include one or more chamber tanks 18 without altering the scope of the present invention.

[0026] Depicted in Figures 2 and 5, the pressure vessel 10 includes a molded polymeric liner 24, which serves as a gas barrier and a pressure containment when assembled as part of the pressure vessel 10. The polymeric liner 24 includes a liner wall 26, an internal cavity 28, a first exterior opening 30, and a second exterior opening 32. The liner wall 26 has a generally tubular shape which extends circumferentially around the internal cavity 28 between the first tank end 14 and the second tank end 16. The first and second extenor openings 30. 32 extend through the first and second tank ends 14, 16, respectively, and allow a fluid and / or a gas 34 to be inserted into and / or removed from the internal cavity 28.

[0027] In addition, the polymeric liner 24 includes a plurality of chambers 36 and a plurality of connectors 38 which are connected in an alternating arrangement between the first and second tank ends 14, 16. Each connector 38 fluidically connects one of the chambers 36 to an adjacent chamber 36, as is commonly known in the art. In addition, the polymeric liner 24 includes a cuff section 40 transitioning between each of the chambers 36 and the adjacent connector 38 or to one of the first and second tank ends 14, 16. The chambers 36, the cuff sections 40, and the connectors 38 of the polymeric liner 24 generally correspond to the chamber tanks 18, the cuff portions 20, and the tank connectors 22, respectively, of the pressure vessel 10. The pressure vessel 10 typically includes a first end fitting 42 and a second end fitting 44 inserted into the respective one of the first and second exterior openings 30, 32. Further, each one of the first and second end fittings 42. 44 includes an inlet / outlet passage 46 for adding and removing the fluid and / or the gas 34, such as hydrogen or the like, from the chambers 36, as is generally known in the art.

[0028] Depicted in Figures 2-10, the pressure vessel 10 also includes a carbon fiber reinforced polymer (CFRP) laminate 48 braided and / or wrapped on an outer surface of the polymeric liner 24 to form a liner assembly 49. The CFRP laminate 48 is a hard outer composite shell surrounding the circumference of the polymeric liner 24 which is configured to reinforce the polymeric liner 24. Further, the CFRP laminate 48 comprises a plurality of uncoated fiber tows 50. one or more permeate conduits 12. resin 52, and an outer surface 54. Depicted in Figure 7, the uncoated fiber tow 50 comprises a plurality of carbon fiber filaments 56 and optionally one or more activated carbon fibers 58 grouped into a bundle 60. Further, the uncoated fiber tow 50 lacks a polymer coating 62 and can readily absorb liquid resin 52 during a resin 52 infusion process, which is further described below. It will be appreciated that the plurality of uncoated fiber tows 50 includes a first uncoated fiber tow 50, a second uncoated fiber tow 50, and the like, and may include a first plurality of uncoated fiber tows 50, second pl urality of uncoated fiber tows 50, and the like. Further, the plurality of carbon fiber filaments 56 forming one of the uncoated fiber tows 50 may be described as a first plurality of carbon fiber filaments 56, a second plurality of carbon fiber filaments 56, and the like.

[0029] Depicted in Figure 8, the permeate conduit 12 comprises a polymer-coated fiber tow 64. The polymer-coated fiber tow 64 comprises a bundle of a plurality of carbon fiber filaments 66 and optionally includes activated carbon fiber 68. Further, polymer-coated fiber tow 64 is coated or encapsulated with a polymer 62, which forms a polymer coating 62 surrounding thecarbon fiber filaments 66 within an interior 67 of the polymer-coated fiber tow 64. It will be appreciated that the polymer coating 62 may encapsulate the carbon fiber filaments 66 and / or saturate the carbon fiber filaments 66. One exemplary polymer 62 is polyamide, which is porous to gaseous permeate and impermeable to liquid resin 52 to provide a barrier during resin 52 infusion. Thus, the polymer-coated fiber tow 64 lacks the cured resin 52 between the polymer coating 62 and an interior 67 of the polymer-coated fiber tow 64. In certain embodiments, the permeate conduit 12 includes a plurality of polymer-coated fiber tows 64 without altering the scope of the present invention.

[0030] Depicted in Figures 6 and 9, the CFRP laminate 48 comprises one or a plurality of permeate conduits 12 interspersed with a plurality of uncoated fiber tows 50. It will be appreciated that the ratio of the uncoated fiber tows 50 and the polymer-coated fiber tows 64 w ithin the CFRP laminate 48 may vary without altering the scope of the present invention. In another exemplary embodiment, the CFRP laminate 48 might be formed out of a plurality of polymer-coated fiber tows 64 with the uncoated fiber tows 50 omitted, without altering the scope of the present invention.

[0031] Depicted in Figure 10, the liner assembly 49 is formed by w rapping or braiding one or more layers of the uncoated fiber tows 50 and one or a plurality of permeate conduits 12 around the outer surface of the polymeric liner 24. Each permeate conduit 12 includes one or more polymer-coated fiber tows 64. In an embodiment illustrated in Figure 10, a radial braiding machine 72 braids the polymer-coated fiber tows 64 and the uncoated fiber tows 50 around the outer surface of the polymeric liner 24 to form the CFRP laminate 48. The polymeric liner 24 acts as a formation mandrel during the process of forming the CFRP laminate 48. Depicted in Figures 9 and 1 1 -15, the CFRP laminate 48 might contain a plurality of wrapped and / or braided layers 74, 76, 78, 80 of polymer-coated fiber tows 64 (i.e., the permeate conduits 12) and / or uncoated fiber tows 50, alternately described as a first layer 74, a second layer 76. and the like. Further, one or a plurality of permeate conduits 12 are optionally included in one or more of the plurality of layers 74, 76, 78, 80. In addition, one or more layers 74, 76, 78, 80 of the plurality of layers 74, 76, 78, 80 might lack a permeate conduit 12 with each of the remaining layers 74, 76, 78, 80 including at least one permeate conduit 12.

[0032] Additional embodiments of the liner assembly 49A. 49B, 49C are illustrated in Figures 11-15, where similar reference numerals represent similar elements or elements with similar function as those described above. Only significant differences between the embodiments arereflected in the Figures and the description below. Depicted in Figure 11, the second embodiment of the liner assembly 49A includes a plurality of uncoated fiber tows 50, a first permeate conduit 12a, and a second permeate conduit 12b braided or wrapped around the liner 24 forming a first braided layer 74 of the CFRP laminate 48. Depicted in Figure 12, a third embodiment of the liner assembly 49B includes a plurality of uncoated fiber tows 50, first and second permeates conduit 12a, 12b, a third permeate conduit 12c, and a fourth permeate conduit 12d braided and / or wrapped around the liner 24 forming one of the braided layers 74. 76 of the CFRP laminate 48. Depicted in Figures 13-15, a fourth embodiment of the liner assembly 49C includes a plurality of uncoated fiber tows 50, first through fourth permeate conduits 12a-12d, a fifth permeate conduit 12e, a sixth permeate conduit 12f, a seventh permeate conduit 12g, and an eighth permeate conduit 12h braided and / or wrapped around the liner 24 forming the outer layer 80 of the CFRP laminate 48. Further, additional permeate conduits 12i, 12j , 12k are optionally included in the first through third layers 74, 76, 78, respectively. It will be appreciated that one of the layers 74, 76, 78, 80 might include a first plurality of permeate conduits 12 and an other one of the layers 74, 76, 78, 80 might include a second plurality of permeate conduits 12. wherein the first and second plurality of permeate conduits 12 might include the same or different amount of permeate conduits 12.

[0033] After wrapping and / or braiding one or more layers 74, 76, 78, 80 of the polymer-coated fiber tows 64 (i.e., the permeate conduits 12) and the uncoated fiber tows 50 on the polymeric liner 24, the liner assembly 49 is typically folded into a desired shape and coated with the liquid resin 52 during a resin 52 infusion process. The liquid resin 52 coats and penetrates the uncoated fiber tows 50 since the uncoated fiber tows 50 lack the polymer coating 62. In contrast, the liquid resin 52 coats the exterior of the polymer coating 62 on the polymer-coated fiber tows 64 and does not penetrate into and / or around the carbon fiber filaments 66 under the polymer coating 62 since the polymer coating 62 is impermeable to the liquid resin 52. In certain embodiments, the uncoated fiber tows 50 might be impregnated with resin 52 prior to the braiding or wrapping process. After the uncoated fiber tows 50 and the polymer-coated fiber tows 64 are coated and / or saturated with the resin 52. the resin 52 is heated or cured to form the CFRP laminate 48 having a hard outer surface 54.

[0034] Depicted in Figure 5, it is commonly known that when the fluid or the gas 34, such as hydrogen gas and the like, is stored under high pressure in the pressure vessel 10 having the polymeric liner 24, gaseous permeate 81 comprising molecules 82 of the fluid or gas 34 willdiffuse from the internal cavity 28, through the polymeric liner 24, and into the CFRP laminate 48, as illustrated by arrow 84. In one exemplary embodiment, the pressure vessel 10 optionally includes a laminate vent 85 extending between the CFRP laminate 48 and an external atmosphere 86, which is configured to vent the gaseous permeate 81 to the external atmosphere 86, as illustrated by arrow 87. In another exemplary7embodiment, the pressure vessel 10 includes a fitting vent 88, which extends between the CFRP laminate 48, through an adjacent one of the first and second end fittings 42, 44, and to the external atmosphere 86. In another exemplary embodiment, the pressure vessel 10 includes a gaseous permeate collection system 90 fluidically connected to the laminate vent 85 and / or the fitting vent 88. The gaseous permeate collection system 90 captures and stores the gaseous permeate 81 exiting from the laminate vent 85 and / or the fitting vent 88, as illustrated by arrow 92. In one exemplary embodiment, the gaseous permeate collection system 90 collects the gaseous permeate 81 and supplies the collected gaseous permeate 81 back to the internal cavity 28 in the pressure vessel 10, as illustrated by arrow 94.

[0035] Shown in Figures 2-4, 6, and 9, the permeate conduit 12 integrated within the CFRP laminate 48 collects the gaseous permeate 81 within the CFRP laminate 48 and transports the gaseous permeate 81 along the continuous polymer-coated fiber tow 64 towards the end fittings 42, 44 of the pressure vessel 10. The permeate conduit 12 formed of the polymer-coated fiber tow 64 is a semipermeable fibrous reinforcement that acts as a conduit under lower pressure within the CFRP laminate 48. In more detail, the permeate conduit 12 includes a polymer- coated fiber tow 64 which is an encapsulated semipermeable carbon fiber tow 64 that has been coated by the polymer 62, such as polyamide, so that the polymer-coated fiber tow 64 is impermeable to liquid resin 52. The polymer coating 62 preserves the porous nature of the carbon fiber 66, 68 during the resin 52 infusion process. Further, the permeate conduit 12 uses the directional nature of the polymer-coated fibrous tow 64 and the porous nature of the carbon fiber 66,68 to absorb and transport the gaseous permeate 81 along the polymer-coated fiber tow 64. In addition, the permeate conduit 12 formed of the polymer-coated fiber tow 64 is braidable around the polymeric liner 24 such that the permeate conduit 12 extends along the pressure vessel 10 between the opposing first and second tank ends 14, 16. As described above, the permeate conduit 12 collects the gaseous permeate 81 and transports the gaseous permeate 81 towards a termination end of the polymer-coated fiber tow 64 so that the gaseous permeate 81 can be returned to the internal cavity 28 in the pressure vessel 10, stored separately, and / orvented in a controlled manner to the external atmosphere 86 near the termination of the polymer-coated fiber tow 64.

[0036] The function of the permeate conduit 12 is described in more detail in reference to Figures 5, 6, and 9. Depicted in Figure 9, the internal cavity 28 of the pressure vessel 10 contains a pressurized gas 34, such as pressurized hydrogen gas or the like. There is an inherent system pressure gradient between the internal cavity 28, the polymeric liner 24. the CFRP laminate 48, and the external atmosphere 86 with the ambient pressure of the external atmosphere 86 being lower than the pressure within the internal cavity' 28. The inherent system pressure gradient drives the diffusion of the gas molecules 82 from the internal cavity 28, through the polymeric liner 24, into the CFRP laminate 48, into the permeate conduits 12, and along the permeate conduits 12. In more detail, the gas molecules 82 permeate and saturate the polymeric liner 24 over time since the pressure of the gas 34 in the polymeric liner 24 is less than the pressure of the gas 34 in the internal cavity' 28. After the polymeric liner 24 is saturated with the gas molecules 82, the gas molecules 82 diffuse through the polymeric liner 24 and into the CFRP laminate 48 under pressure to form the gaseous permeate 81, since the pressure of the gas 34 within the polymeric liner 24 is greater than the pressure of the gas 34 within the CFRP laminate 48. Next, the gaseous permeate 81 travels through the CFRP laminate 48 and permeates through the polymer coating 62 on the permeate conduit 12 (arrow 96) since the polymer-coated fiber tows 64 are semipermeable for the gas molecules 82 after encapsulation by the cured resin 52 and the pressure of the gas 34 within the polymer-coated fiber tows 64 is less than the pressure of the gas 34 within the cured resin 52 in the CFRP laminate 48. Gaseous permeate 81 which has entered into the polymer-coated fiber tow 64 is shown as element 97.

[0037] In contrast, the gaseous permeate 81 is not able to enter the uncoated fiber tows 50 (arrow 98) which have been saturated with cured resin 52. During the resin 52 infusion process, the liquid resin 52 impregnates the uncoated fiber tows 50. Curing of the resin 52 causes the uncoated fiber tows 50 to be generally impermeable for the gaseous permeate 81.

[0038] Gaseous permeate 81 that is not collected by the permeate conduit 12 adjacent the polymeric liner 24 continues to diffuse through the CFRP laminate 48 towards the outer surface 54, as illustrated by arrow 100. When the CFRP laminate 48 includes a plurality of layers 74, 76. 78. 80 of the uncoated fiber tows 50 and the polymer-coated fiber tows 64, the gaseous permeate 81 that does not saturate into the permeate conduit 12 in the first layer 74 will continue to diffuse towards subsequent permeate conduits 12 of the adjacent layers 74, 76, 78,80. The additional gaseous permeate 81 can be collected by the subsequent permeate conduits 12 within the layers 74, 76, 78, 80, as illustrated by arrow 102. In one embodiment, the CFRP laminate 48 is formed out of a plurality of the polymer-coated fiber tows 64 with the uncoated fiber tows 50 omitted in order to maximize the collection of gaseous permeate 81.

[0039] Depicted in Figures 5 and 6, each one of the permeate conduits 12 acts as a conduit under lower pressure (in comparison to the pressure of the gas molecules 82 in the CFRP laminate 48) and direct the gaseous permeate 81 along the continuous polymer-coated fiber tow 64 (arrow 104) towards the first and second end fittings 42, 44, where the gaseous permeate 81 is collected (arrow 92) and returned to the pressure vessel 10 (arrow 94) and / or stored separately by the gaseous permeate collection system 90. In one exemplary embodiment, the gaseous permeate 81 is vented (arrow 87) in a controlled matter through the vent 85, 88 to the external atmosphere 86 at the termination of the permeate conduit 12.

[0040] As discussed above, the pressure vessel 10 of the present invention includes a polymeric liner 24 and a CFRP laminate 48 surrounding and supporting the polymeric liner 24. The CFRP laminate 48 includes one or more permeate conduits 12 formed out polymer-coated fiber tow 64 braided and / or wrapped around polymeric liner 24. The permeate conduit 12 reduces the accumulation of gaseous permeate 81 between the polymeric liner 24 and the CFRP laminate 48 by collecting and transporting the gaseous permeate 81 towards the tank ends 14, 16. Further, the pressure vessel 10 optionally includes one or more of a laminate vent 85 and a fitting vent 88, which allows the collected gaseous permeate 81 to be reclaimed for storage, resupplied to the pressure vessel 10, and / or vented to the external atmosphere 86. The permeate conduits 12 minimize the accumulation of gaseous permeate 81 in the polymeric liner 24 and the in the CFRP laminate 48, which reduces the potential for the polymeric liner 24 to collapse during rapid defueling events and reduces the potential for blisters to form in the polymeric liner 24. The permeate conduit 12 also increases the storage capacity of the pressure vessel 10 by minimizing losses of stored capacity in the pressure vessel 10 due to the migration of the gaseous permeate 81 out of the pressure vessel 10.

[0041] The invention has been described in an illustrative manner, and it is to be understood that the terminology’, which has been used, is intended to be in the nature of words of description rather than of limitation. Many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood thatwithin the scope of the appended claims, the invention may be practiced other than as specifically described.

Claims

What is claimed is:

1. A pressure vessel comprising: a polymeric liner comprising a liner wall, an internal cavity, and a first exterior opening, wherein the liner wall has a tubular shape which extends circumferentially around the internal cavity and the first exterior opening extends through the liner wall to the internal cavity; and a carbon fiber reinforced polymer (CFRP) laminate surrounding a circumference of the polymeric liner, the CFRP laminate includes an uncoated fiber tow and a permeate conduit wrapped or braided around the polymeric liner and coated with a resin; wherein the uncoated fiber tow is impregnated with a cured resin; and wherein the permeate conduit comprises a polymer-coated fiber tow which has been coated with a polymer forming a polymer coating that is impermeable to a liquid resin such that the polymer-coated fiber tow lacks the cured resin between the polymer coating and an interior of the polymer-coated fiber tow.

2. The pressure vessel as set forth in claim 1, wherein: the uncoated fiber tow further comprises a first plurality of carbon fiber filaments which are uncoated by the polymer; and the polymer-coated fiber tow further comprises a second plurality of carbon fiber filaments which are coated or encapsulated by the polymer, and which lack the cured resin between the polymer and the second plurality of carbon fiber filaments.

3. The pressure vessel as set forth in claim 2, wherein: the polymer comprises polyamide.

4. The pressure vessel as set forth in claim 3, further comprising a gaseous permeate which diffuses from the internal cavity, through the polymeric liner, and into the CFRP laminate also diffuses into the permeate conduit; and the permeate conduit transports the gaseous permeate along the permeate conduit.

5. The pressure vessel as set forth in claim 4, wherein: one or more of the first plurality of carbon fiber filaments and the second plurality of carbon fiber filaments includes an activated carbon fiber.

6. The pressure vessel as set forth in claim 5, wherein: the uncoated fiber tow comprises a plurality of uncoated fiber tows; andthe permeate conduit comprises a plurality of permeate conduits.

7. The pressure vessel as set forth in claim 6, wherein: the plurality of uncoated fiber tows and the plurality of permeate conduits are braided or w rapped around the polymeric liner forming a plurality of layers; the plurality of permeate conduits includes a first permeate conduit and a second permeate conduit; the plurality of layers includes a first layer and a second layer; and the first layer includes the first permeate conduit and the second layer includes the second permeate conduit.

8. The pressure vessel as set forth in claims 4 to 7, further comprising: a first end fitting inserted into the first exterior opening in the polymeric liner and having a passage fluidically connected to the internal cavity.

9. The pressure vessel as set forth in claim 8, further comprising: a laminate vent extending between the CFRP laminate and an external atmosphere; wherein the permeate conduit is fluidically connected to the laminate vent; and wherein the gaseous permeate from the permeate conduit is vented to the external atmosphere through the laminate vent.

10. The pressure vessel as set forth in claim 8, further comprising: a fitting vent extending between the CFRP laminate and through the first end fitting; wherein the permeate conduit is fluidically connected to the fitting vent.

11. The pressure vessel as set forth in claim 8, further comprising: a vent fluidically connected to the permeate conduit in the CFRP laminate; and a gaseous permeate collection system which collects the gaseous permeate from the vent; wherein the gaseous permeate collection system stores the collected gaseous permeate or wherein the gaseous permeate collection system supplies the collected gaseous permeate to the internal cavity of the pressure vessel.

12. A pressure vessel comprising: a polymeric liner comprising a liner wall, an internal cavity, and a first exterior opening, wherein the liner wall has a generally tubular shape which extends circumferentially aroundthe internal cavity and the first exterior opening extends through the liner wall to the internal cavity; and a carbon fiber reinforced polymer (CFRP) laminate surrounding a circumference of the polymeric liner, the CFRP laminate includes a plurality of permeate conduits wrapped or braided around the polymeric liner and coated with a resin; wherein each permeate conduit of the plurality of permeate conduits comprises a polymer-coated fiber tow which has been coated with a polymer forming a polymer coating that is impermeable to liquid resin such that the polymer-coated fiber tow lacks the cured resin between the polymer coating and an interior of the polymer-coated fiber tow.

13. The pressure vessel as set forth in claim 12, the CFRP laminate further comprising: a plurality of uncoated fiber tows wrapped or braided around the polymeric liner and coated with the resin; wherein each uncoated fiber tow of the plurality of uncoated fiber tows is impregnated with the cured resin.

14. The pressure vessel as set forth in claim 13, wherein: each one of the plurality of uncoated fiber tows further comprises a first plurality of carbon fiber filaments which are uncoated by the polymer; and the polymer-coated fiber tow further comprises a second plurality of carbon fiber filaments which are coated or encapsulated by the polymer, and which lack the cured resin between the polymer and the second plurality of carbon fiber filaments.

15. The pressure vessel as set forth in claim 14, wherein: the polymer is polyamide.

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