Circumferentially continuous, axially and radially stretchable, flame retardant, puncture resistant insulating knit sleeve

Abstract

A sleeve for providing protection to busbars interconnecting cells in an electric vehicle battery has a knitted wall having a circumferentially continuous outer surface extending along a longitudinal axis between opposing open ends. The knitted wall is formed from multifilament flame-resistant yarn having a fineness between 30 tex and 420 tex. An impermeable coating extends over the entire outer surface of the knitted wall.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Application Serial No. 63 / 434,539, filed December 22, 2022, and priority to U.S. Application Serial No. 18 / 391,650, filed December 20, 2023, both of which are incorporated by reference in their entireties. [Background technology]

[0002] Background of the Invention 1.Technical Field This invention relates generally to a knitted sleeve for protection of an elongated member contained therein, and more particularly to a circumferentially continuous, axially and radially stretchable, flame retardant, puncture resistant, insulating knitted sleeve.

[0003] 2. Related technologies It is known to enclose elongated members, such as wires, wire harnesses, cables, and various types of conduit, in a sleeve having a circumferentially continuous cylindrical wall to provide the elongated member with protection against impact and abrasion, liquids, and external thermal effects. However, there remains a need for a protective sleeve that can provide insulating, fire-retardant, and puncture-resistant protection to the elongated member contained therein, while achieving a consistent low profile for the elongated member and its connectors so as not to be cumbersome, unsightly, or bulky. There is a further need for a protective sleeve that protects the busbar connections between cells of a battery pack in an electric vehicle battery system and enables the vehicle to remain drivable under power from the battery system for at least five minutes after a thermal runaway condition of one or more cells of the battery, allowing the driver of the electric vehicle sufficient time to safely maneuver to a suitable parking location and leave the vehicle. Summary of the Invention [Means for solving the problem]

[0004] Summary of the Invention One object of the present disclosure is to provide a stretchable knit sleeve that provides insulating, fire-suppressing protection to an elongated member contained therein.

[0005] Another object of the present disclosure is to provide protection for the busbar connections between cells of a battery pack in an electric vehicle battery system, allowing the driver of the electric vehicle sufficient time to safely maneuver to a suitable parking spot and empty the vehicle.

[0006] Another object of the present disclosure is to provide protection for busbar connections between cells of a battery pack of an electric vehicle battery system via a knitted sleeve, allowing the battery system to power the electric vehicle for five minutes or more after a cell experiences thermal runaway.

[0007] Another object of the present disclosure is to provide a protective member that is easy to place on the bus bar connections and connectors between cells of a battery pack of an electric vehicle battery system.

[0008] Another object of the present disclosure is to provide a knitted sleeve that can fit over busbar connections between cells of a battery pack in an electric vehicle battery system in a snug fit relationship to the busbar and any connectors attached thereto.

[0009] Another object of the present disclosure is to provide a knitted sleeve that can fit over busbar connections between cells of a battery pack in an electric vehicle battery system and can resist rupturing or tearing when impacted by an external impact force.

[0010] In accordance with these and other objects, a sleeve is provided for providing protection to busbars interconnecting cells in an electric vehicle battery. The sleeve has a knitted wall having a circumferentially continuous outer surface extending along a longitudinal axis between opposed open ends. The knitted wall is formed, at least in part, from multifilament flame-resistant yarns having a fineness between 30 tex and 420 tex. The knit structure of the knitted wall is axially and radially stretchable, thereby allowing the knitted wall to easily flex and assemble into a closely fitting, wrinkle-free relationship against the busbar, regardless of the number of bends and the shape of the outer contour of the busbar's outer surface. An impervious coating is provided extending over the outer surface of the knitted wall to prevent the ingress and penetration of electrically charged dust, particles, and smoke through the knitted wall, enhancing the flame resistance and flame retardancy of the sleeve.

[0011] According to another aspect of the invention, the knit wall is formed entirely from multifilament flame-resistant yarns having a fineness between 30 tex and 420 tex.

[0012] According to another aspect of the invention, the knit wall is formed entirely from multifilament flame-resistant yarns having a fineness between 100 tex and 180 tex.

[0013] According to another aspect of the invention, the knit wall is formed entirely from multifilament flame-resistant yarns having a fineness between 120 tex and 160 tex.

[0014] In accordance with another aspect of the present invention, the impermeable coating is elastomeric and stretchable to maintain the underlying knitted wall in a stretchable manner, thereby facilitating the formation of a wrinkle-free, snug fit of the knitted wall to the busbar.

[0015] In accordance with another aspect of the invention, the impermeable coating is one of a silicone-based, pure silicone, liquid silicone rubber, polytetrafluoroethylene, or polyurethane layer bonded directly to the outer surface of the knitted wall.

[0016] According to another aspect of the invention, the impermeable coating has a thickness of between about 0.05 mm and 4.0 mm, preferably between about 0.05 mm and 1.0 mm, and more preferably between about 0.05 mm and 0.3 mm.

[0017] According to another aspect of the invention, the multifilament flame resistant yarn extends in a warp direction generally parallel to the longitudinal axis and in a circumferential weft direction relative to the longitudinal axis.

[0018] According to another aspect of the present invention, the flame resistant yarn is a mineral yarn. According to other aspects of the present invention, the mineral yarn may be provided as at least one of fiberglass, silica, and basalt.

[0019] In accordance with another aspect of the present invention, the knit wall may be knitted using a rib knitting pattern having raised ribs extending in at least one of the warp and / or circumferential weft (fill) directions, the ribs providing enhanced softness, conformability, and stretchability.

[0020] In accordance with another aspect of the present invention, a rib knit pattern may be formed by alternating knit and purl stitches in a 1x1 or 2x2 pattern.

[0021] According to another aspect of the invention, the stitch size is between 4 and 20 stitches per 2 cm in the course direction, more preferably between 10 and 17 stitches per 2 cm, and between 4 and 22 stitches per 2 cm in the wale direction, more preferably between 9 and 15 stitches per 2 cm.

[0022] In accordance with another aspect of the present invention, the rib knitting pattern may include slip stitches that increase the height of the rib(s).

[0023] According to another aspect of the present invention, a sleeve for protecting busbar connections between cells in an electric vehicle battery pack is provided. The sleeve comprises a tubular knitted wall having a circumferentially continuous outer surface extending along a longitudinal axis between opposed open ends. The knitted wall is formed from multifilament flame-resistant yarn having a fineness between 30 tex and 420 tex and an outermost impermeable coating, the impermeable coating being stretchable to maintain the underlying knitted wall in a stretchable state, thereby facilitating the formation of a wrinkle-free, snug fit of the knitted wall against the busbar.

[0024] According to another aspect of the present invention, the knit wall is made of multifilament flame-resistant yarns having a fineness between 100 tex and 180 tex.

[0025] According to another aspect of the present invention, the knit wall is made of multifilament flame-resistant yarns having a fineness between 120 tex and 160 tex.

[0026] According to another aspect of the present invention, the multifilament flame-resistant yarn comprises stitches having a stitch size of between 4 and 20 stitches per 2 cm in the course direction extending circumferentially, and a stitch size of between 4 and 22 stitches per 2 cm in the wale direction extending vertically.

[0027] According to another aspect of the present invention, the multifilament flame-resistant yarn has stitches having a stitch size of between 10 and 17 stitches every 2 cm in the course direction extending circumferentially, and a stitch size of between 9 and 15 stitches every 2 cm in the wale direction extending vertically.

[0028] In accordance with another aspect of the present invention, the impermeable elastomeric coating comprises a silicone-based coating.

[0029] According to another aspect of the invention, there is provided a method of constructing a sleeve for providing insulating protection to busbars interconnecting batteries in an electric vehicle, the method including knitting a multifilament flame-resistant yarn having a fineness between 30 tex and 420 tex to form a wall having a circumferentially continuous outer surface extending along a longitudinal axis between opposed open ends, and forming an impermeable coating on the outer surface of the knitted wall, the impermeable coating being stretchable to maintain the underlying knitted wall stretchable, thereby facilitating the formation of a wrinkle-free, snug fit of the knitted wall against the busbar.

[0030] According to another aspect of the invention, the method includes knitting the wall entirely with multifilament flame-resistant yarn having a fineness between 100 tex and 180 tex.

[0031] According to another aspect of the invention, the method includes knitting the wall entirely with multifilament flame-resistant yarn having a fineness between 120 tex and 160 tex.

[0032] According to another aspect of the invention, the method further comprises knitting a stitch size in the course direction between 4 and 20 stitches per 2 cm, more preferably between 10 and 17 stitches per 2 cm, and in the wale direction between 4 and 22 stitches per 2 cm, more preferably between 9 and 15 stitches per 2 cm.

[0033] In accordance with another aspect of the invention, the method further includes adhering an impermeable, elastically stretchable coating to the exterior surface of the knitted wall.

[0034] In accordance with another aspect of the invention, the method further includes adhering an impermeable, elastically stretchable coating having a uniform thickness over the entire knitted wall.

[0035] According to another aspect of the invention, the method further includes forming the impermeable, elastically stretchable coating from one of a silicone, silicone-based, liquid silicone rubber, polytetrafluoroethylene, or polyurethane layer.

[0036] According to another aspect of the invention, the method may further include providing the multifilament flame resistant yarn from at least one of glass fiber, silica, and basalt.

[0037] BRIEF DESCRIPTION OF THE DRAWINGS These and other aspects, features and advantages of the present invention will become readily apparent to those of ordinary skill in the art upon consideration of the following detailed description of the presently preferred embodiment and best mode, the appended claims and the accompanying drawings. [Brief explanation of the drawings]

[0038] [Figure 1] FIG. 1 is a perspective view of an electric vehicle having one or more knitted sleeves constructed in accordance with one aspect of the present disclosure positioned against electric vehicle battery components to be protected. [Figure 2A] FIG. 2A is an enlarged, fragmentary, schematic perspective view of a knitted sleeve constructed in accordance with one embodiment of the present disclosure shown positioned relative to an elongated member to be protected with the textile sleeve. [Figure 2B] FIG. 2B is a view similar to FIG. 2A illustrating a sleeve constructed in accordance with another embodiment of the present disclosure shown positioned relative to an elongated member to be protected. [Figure 2C] FIG. 2C is a view similar to FIG. 2B illustrating a sleeve constructed in accordance with another embodiment of the present disclosure shown positioned relative to an elongated member to be protected. [Figure 3] FIG. 3 is an enlarged schematic cross-sectional view taken generally along line 3-3 of FIG. 2A. [Figure 4] FIG. 4 is a fragmentary view of a wall of a sleeve constructed in accordance with one aspect of the present disclosure, showing the knitting thereof. DETAILED DESCRIPTION OF THE INVENTION

[0039] Detailed Description of the Preferred Embodiments 2A and 3 illustrate a textile sleeve, hereinafter referred to as sleeve 10, constructed in accordance with one aspect of the present invention, having a stretchable textile knit wall 12 disposed about an elongated member 11 to be protected, such as a bus bar interconnecting adjacent cells of a battery pack B (FIG. 1) of a vehicle, such as an electric vehicle (EV). Knit wall 12 has a circumferentially continuous outer surface 13 that extends between open opposed ends 14, 16 and longitudinally relative to a central longitudinal axis 18, enclosing a central cavity 20 through which elongated member 11 extends. Within central cavity 20, elongated member 11 is protected against impact forces, abrasion, and ingress of contaminants, such as might be experienced during a vehicle collision, by way of example and not limitation. Wall 12 inhibits the spread of flame in the event of thermal runaway in one or more cells of battery pack B, thereby allowing electric vehicle EV to maintain battery power for at least five minutes or more and safely drive the electric vehicle to a parking spot where the driver can evacuate. Flexible knit wall 12 is formed at least in part or entirely by knitting flame-resistant, impact-resistant multifilament yarn 22 (FIG. 3) having a fineness between 30 tex and 420 tex. Knit wall 12 in FIG. 2A is shown as having generally smooth inner and outer surfaces along the length of sleeve 10 and may be formed by any stretchable knit, such as produced via a jersey knit (FIG. 4) or tricot knit, by way of example and not limitation.

[0040] According to a further aspect, the multifilament yarn 22 of the sleeve 10′, 10″ configured according to an aspect of the present disclosure can be knit using a rib stitch pattern that enhances the stretchability of the wall 12 and facilitates ease of assembly of the sleeve 10 to the elongate member 11 and any connectors thereon. A plurality of ribs (R) are formed via alternating knit and purl stitches in a 1×1 or 2×2 knit pattern that forms longitudinally extending (warp direction) ribs R (sleeve 10′ shown in FIG. 2B) and / or circumferentially extending (weft or filling) ribs R (sleeve 10″ shown in FIG. 2C), facilitating the formation of a wrinkle-free, snug fit of the knit wall 12 to the busbar 11, thereby facilitating assembly and flame suppression.

[0041] Regardless of the stitch type used to construct wall 12, wall 12 is knitted to be low-profile and unobtrusive, and therefore aesthetically appealing. Knitted wall 12 may be knitted via a weft knitting process, a warp knitting process, a flatbed knitting machine, or a circular knitting machine. Nevertheless, the knit structure of knitted wall 12 is axially and radially stretchable, allowing knitted wall 12 to easily flex and assemble into a close, snug-fitting relationship with busbar 11 and any connectors thereon.

[0042] To further enhance the flame resistance, impact resistance, puncture / tear resistance, and resilience of sleeve 10, 10', 10" a tough impermeable elastomeric coating 26 is provided extending over outer surface 13 of knitted wall 12. Coating 26 further prevents the ingress and penetration of dust, particles, and smoke through knitted wall 12. Impermeable coating 26 is resiliently stretchable and elastic in all directions, including longitudinally and radially, to allow underlying knitted wall 12 to remain stretchable along longitudinal and radial directions, thereby facilitating a wrinkle-free, snug fit of knitted wall 12, and thus sleeve 10, to busbar 11 and any connectors thereon.

[0043] When subjected to an extreme thermal scenario, such as an unintended thermal runaway condition in a cell of battery pack B, the flame-resistant multifilament yarn 22 maintains its structural integrity and inhibits flame growth and propagation for at least five minutes or more, thereby allowing sufficient time for occupants of the automobile EV to park and / or evacuate the automobile EV. According to a further aspect, the wall 12 may be knitted using flame-resistant multifilament yarn 22 provided with a fineness between 100 tex and 180 tex, and in one exemplary embodiment, may be entirely knitted using flame-resistant multifilament yarn 22 having a fineness between 100 tex and 180 tex, and in another exemplary embodiment, may be entirely knitted using flame-resistant multifilament yarn 22 having a fineness between 120 tex and 160 tex. It has been discovered that to optimize the ability of the wall 12 to suppress the propagation of a flame for a period of at least 5 minutes, the stitch size design has between 4 and 20 stitches per 2 cm in the circumferential course direction, more preferably between 10 and 17 stitches per 2 cm, and between 4 and 22 stitches per 2 cm in the longitudinal wale direction, more preferably between 9 and 15 stitches per 2 cm.

[0044] An impermeable coating 26, such as a silicone, silicone-based, liquid silicone rubber, polytetrafluoroethylene, or polyurethane coating, may be applied and adhered to the exterior surface 13, and coating 28, also referred to as layer 26, may be adhered directly to the exterior surface 13. The impermeable layer 26 may be applied to the exterior surface 13 using any desired process that allows the desired thickness (t) of the layer 26 to be achieved. In an exemplary embodiment, the thickness t is between about 0.05 and 4.0 mm, preferably between about 0.05 and 1.0 mm, and more preferably between about 0.1 and 0.3 mm. When layer 26 is applied within the aforementioned thickness t range, the flexibility and conformability of the wall 12 remains, optimal dielectric strength is provided, and a breakdown voltage of between about 5 and 40 kV may be provided. Thus, the elongated member 11 is protected against unwanted electrical interference, including electromagnetic interference (EMI), radio frequency interference (RFI), and electrostatic discharge (ESD). In addition to various electrical protections, layer 26 may provide significantly enhanced protection for the elongated member 11 against impact forces. Additionally, layer 26 may be hydrophobic and impervious to fluids and debris, thereby providing enhanced protection against the ingress of contaminants such as fluid gases and solid debris.

[0045] According to another aspect, a method of constructing a sleeve 10 is provided. The method includes knitting a multifilament flame-resistant yarn having a fineness between 30 tex and 420 tex to form a textile wall 12 having a circumferentially continuous outer surface 13 extending along a longitudinal axis 18 between opposed open ends 14, 16.

[0046] In accordance with another aspect of the present invention, the method may further include knitting the multifilament flame-resistant yarn using a rib stitch pattern to form ribs R extending longitudinally along the longitudinal axis 18 of the sleeve 10, the ribs R increasing the flame resistance of the wall 12 while simultaneously increasing the stretchability of the wall 12 in both the radial and axial directions.

[0047] According to another aspect of the present invention, the method further includes entirely knitting the wall 12 with multifilament flame-resistant yarn 22 having a fineness between 100 tex and 180 tex, and in one exemplary embodiment between 120 tex and 160 tex.

[0048] According to another aspect of the invention, the method further comprises knitting a stitch size in the course direction between 4 and 20 stitches per 2 cm, more preferably between 10 and 17 stitches per 2 cm, and in the wale direction between 4 and 22 stitches per 2 cm, more preferably between 9 and 15 stitches per 2 cm.

[0049] In accordance with another aspect of the present invention, the method may further include adhering an impermeable coating 26 to the outer surface 13 of the textile wall 12, the impermeable coating 26 being formed from an elastomeric material that enhances the stretchability and elasticity of the sleeve 10.

[0050] In accordance with other aspects of the invention, the method may further include forming the impermeable coating 26 using an elastomer, stretchable silicone, silicone-based, liquid silicone rubber, polytetrafluoroethylene, or polyurethane material.

[0051] Obviously, many modifications and variations of the present invention are possible in light of the above teachings. It is contemplated that all features of all claims and all embodiments may be combined with each other unless the combinations are mutually inconsistent. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced other than as specifically described.

Claims

1. A sleeve for protecting an elongated member, comprising: a knitted wall having a circumferentially continuous outer surface extending along a longitudinal axis between opposed open ends, the knitted wall being formed at least in part from multifilament flame-resistant yarn having a fineness between 30 tex and 420 tex; The sleeve further comprises an impermeable elastomeric coating extending over the outer surface of the knitted wall.

2. 2. The sleeve of claim 1, wherein the knit wall is formed entirely of multifilament flame-resistant yarn having a fineness between 30 tex and 420 tex.

3. 3. The sleeve of claim 2, wherein the knitted wall is formed entirely of multifilament flame-resistant yarn having a fineness between 100 tex and 180 tex.

4. 4. The sleeve of claim 3, wherein the knit wall is formed entirely of multifilament flame-resistant yarn having a fineness between 120 tex and 160 tex.

5. The sleeve of claim 1 , wherein the impermeable elastomeric coating is one of a silicone, silicone-based, liquid silicone rubber, polytetrafluoroethylene, or polyurethane layer bonded directly to the outer surface.

6. The sleeve of claim 5, wherein the impermeable elastomeric coating has a thickness of between about 0.05 and 4.0 mm.

7. 3. The sleeve of claim 2, wherein the multifilament flame resistant yarn is a mineral yarn.

8. The sleeve of claim 7 , wherein the mineral yarn is at least one of fiberglass, silica, and basalt.

9. The sleeve according to claim 2, wherein the multifilament flame-resistant yarn is knitted to have a stitch size of between 4 and 20 stitches per 2 cm in a course direction extending circumferentially and between 4 and 22 stitches per 2 cm in a wale direction extending vertically.

10. The sleeve according to claim 9, wherein the multifilament flame-resistant yarn is knitted to have a stitch size of between 10 and 17 stitches per 2 cm in a course direction extending circumferentially and between 9 and 15 stitches per 2 cm in a wale direction extending vertically.

11. 2. The sleeve of claim 1, wherein the multifilament flame resistant yarn is braided to form longitudinally extending ribs and / or circumferentially extending ribs.

12. The sleeve of claim 11 , wherein the plurality of ribs are formed via alternating knit and purl stitches in a desired pattern.

13. 1. A sleeve for protecting busbar connections between cells of a battery pack of an electric vehicle, comprising: a knitted wall and an impermeable elastomeric coating; the knitted wall has a circumferentially continuous outer surface extending along a longitudinal axis between opposed open ends, the knitted wall being formed from multifilament flame-resistant yarn having a fineness between 30 tex and 420 tex; The impermeable elastomeric coating extends against the outer surface of the knitted wall.

14. 14. The sleeve of claim 13, wherein the knitted wall is formed from multifilament flame-resistant yarns having a fineness between 100 tex and 180 tex.

15. 15. The sleeve of claim 14, wherein the knitted wall is formed from multifilament flame-resistant yarns having a fineness between 120 tex and 160 tex.

16. The sleeve according to claim 14, wherein the multifilament flame-resistant yarn is knitted to have a stitch size of between 4 and 20 stitches per 2 cm in a course direction extending circumferentially and between 4 and 22 stitches per 2 cm in a wale direction extending vertically.

17. The sleeve according to claim 16, wherein the multifilament flame-resistant yarn is knitted to have a stitch size of between 10 and 17 stitches per 2 cm in a course direction extending circumferentially and between 9 and 15 stitches per 2 cm in a wale direction extending vertically.

18. The sleeve of claim 13 , wherein the impermeable elastomeric coating is silicone-based.

19. 1. A method of constructing a sleeve for providing insulating protection to bus bars interconnecting cells of a battery pack of an electric vehicle, comprising: knitting a multifilament flame resistant yarn having a fineness between 30 tex and 420 tex to form a textile wall having a circumferentially continuous outer surface extending along a longitudinal axis between opposed open ends; and adhering an impermeable elastomeric coating to the outer surface of the textile wall.

20. 20. The method of claim 19, further comprising knitting the multifilament flame resistant yarn to have a stitch size of between 4 and 20 stitches per 2 cm in a circumferentially extending course direction and between 4 and 22 stitches per 2 cm in a longitudinally extending wale direction.

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