Composite cross beam for battery pack of electric vehicle

Abstract

The invention relates to a composite cross-member for an electric vehicle battery pack. A beam for supporting a plurality of prismatic battery packs in a battery pack housing of an electric vehicle including a base has a lower elongate horizontal flange and an upper elongate horizontal flange narrower than the lower elongate horizontal flange, spaced above the lower elongate horizontal flange by a vertical web. A web member may be disposed on the upper elongate horizontal flange of the base and include first and second elongate outer vertical wall members. At least two elongate inserts are disposed between the vertical outer wall members and configured to at least partially form at least one longitudinally extending channel therebetween. The elongate insert may be made of metal, and the longitudinally extending channel provides access for a cooling fluid. The cover may engage upper edges of the vertical wall members and enclose the metal insert in a space between the first and second vertical wall members.

Description

Technical Field

[0001] The present disclosure relates to composite cross - beams for electric vehicle battery packs. Background Art

[0002] Electric vehicle battery packs typically have multiple laterally - extending metal cross - beams for supporting multiple rows of prismatic battery cells spaced between the cross - beams. In addition to supporting the battery cells, the cross - beams also increase the strength of the battery pack and help conduct heat away from the battery pack. However, metal cross - beams are typically heavy, significantly increasing the mass of the battery pack and the mass of the electric vehicle containing the battery pack. Additionally, the metal beams typically must be electrically insulated in case of battery pack failure. Summary of the Invention

[0003] Embodiments of the present disclosure provide a composite cross - beam for an electric vehicle battery pack. According to one such embodiment, a beam is provided for supporting multiple prismatic battery cells in a battery housing of an electric vehicle. The beam may include a base having a lower elongated horizontal flange and an upper elongated horizontal flange, the upper elongated horizontal flange being narrower than the lower elongated horizontal flange and spaced above and generally centered over the lower elongated horizontal flange by a web.

[0004] A web member may be disposed on the upper elongated horizontal flange of the base. The web member may have first and second elongated outer vertical wall members having upper and lower edges. The lower edges engage and are supported on the base. At least two elongated inserts, optionally made of metal, may be disposed between the vertical outer wall members and configured to form at least one longitudinally - extending channel therebetween for circulation of a cooling fluid.

[0005] A cover may engage the upper edges of the outer vertical wall members and enclose the metal inserts in a space between the first and second outer vertical wall members.

[0006] In some embodiments, the base may be made of a carbon fiber composite material. In some embodiments, the first and second outer elongated vertical wall members are made of a carbon fiber composite material. The first and second elongated outer vertical wall members may comprise from about 35% to about 50% fiber - reinforcing material, and in some embodiments, at least about 80% of the fibers in the first and second elongated outer vertical wall members are oriented parallel to the longitudinal direction.

[0007] In some embodiments, the elongated inserts are made of metal (such as copper, aluminum, and magnesium). In some embodiments, the cover is made of metal, a composite material, or a polymer.

[0008] In some embodiments, a fiberglass layer between each metal insert and its corresponding elongated outer vertical web member. A plurality of surface features may be present on the inner surface of the elongated vertical web member, the plurality of surface features increasing the turbulence of the cooling fluid in at least one longitudinally extending channel between the elongated vertical wall members.

[0009] In some embodiments, the at least two elongated inserts may be at least partially bonded to the elongated outer vertical wall member. In other embodiments, the at least two elongated inserts may be at least partially molded into the elongated outer vertical wall member.

[0010] The outer surface of each elongated outer vertical wall member may be non-conductive. In some embodiments, each elongated outer vertical wall member has a thickness of about 0.75 to about 1 mm and a thermal conductivity of about 0.4 to about 0.8 W / mK. In other embodiments, each elongated outer vertical wall member has a thickness of about 1.5 mm and a thermal conductivity of about 0.8 to about 1.2 W / mK.

[0011] The present invention also discloses the following solutions:

[0012] Solution 1. A beam for supporting a plurality of prismatic battery packs in a battery pack housing of an electric vehicle, the beam comprising:

[0013] A base having a lower elongated horizontal flange and an upper elongated horizontal flange, the upper elongated horizontal flange being narrower than the lower elongated horizontal flange, spaced above the lower elongated horizontal flange by a vertical web and generally centered;

[0014] A web member disposed on the upper elongated horizontal flange of the base, the web member including first and second elongated outer vertical wall members, the web member having an upper edge and a lower edge, wherein the lower edge engages the base; at least two elongated inserts are disposed between the vertical outer wall members and configured to form at least one longitudinally extending channel for cooling fluid in the web member.

[0015] Solution 2. The beam according to Solution 1, further comprising a cover that engages the upper edge of the vertical wall member and encloses the insert in the space between the first and second elongated outer vertical wall members.

[0016] Solution 3. The beam according to Solution 1, wherein the base is made of a carbon fiber composite material.

[0017] Solution 4. The beam according to Solution 1, wherein the first and second elongated vertical wall members are made of a carbon fiber composite material.

[0018] Solution 5. The beam according to Solution 1 further includes a fiberglass layer on the outer surfaces of the first and second elongated vertical wall members.

[0019] Solution 6. The beam according to Solution 1, wherein the elongated insert is made of metal.

[0020] Solution 7. The beam according to Solution 1 further includes a plurality of surface features on the inner surface of the elongated vertical web member, the plurality of surface features increasing the turbulence of the cooling fluid in the channel formed between the elongated insert and the elongated vertical wall member.

[0021] Solution 8. The beam according to Solution 1, wherein at least a portion of each of the at least two elongated inserts is coupled to at least one of the elongated outer vertical wall members.

[0022] Solution 9. The beam according to Solution 1, wherein at least a portion of the at least two elongated inserts is molded into at least one of the elongated outer vertical wall members.

[0023] Solution 10. The beam according to Solution 1, wherein the outer surface of at least each elongated outer vertical wall member is non-conductive.

[0024] Solution 11. The beam according to Solution 10, wherein each elongated outer vertical wall member has a thickness of about 0.75 to about 1 mm and a thermal conductivity of about 0.4 to about 0.8 W / mK.

[0025] Solution 12. The beam according to Solution 10, wherein each elongated outer vertical wall member has a thickness of about 1.5 mm and a thermal conductivity of about 0.8 to about 1.2 W / mK.

[0026] Solution 13. The beam according to Solution 1, wherein the first and second elongated outer vertical wall members comprise about 35% to about 50% fiber-reinforced material.

[0027] Solution 14. The beam according to Solution 13, wherein at least about 80% of the fibers in the first and second elongated outer vertical wall members are parallel to the longitudinal direction.

[0028] Solution 15. A beam for supporting a plurality of prismatic battery packs in a battery pack housing of an electric vehicle, the beam comprising:

[0029] A base of composite polymer material having a lower elongated horizontal flange and an upper elongated horizontal flange, the upper elongated horizontal flange being narrower than the lower elongated horizontal flange and spaced apart and generally centered above the lower elongated horizontal flange by a vertical web;

[0030] A web member is disposed on the upper elongated horizontal flange of the base. The web member includes first and second elongated outer vertical wall members of a composite polymer material and has a non-conductive outer surface, an upper edge, and a lower edge, wherein the lower edge engages the base; at least two elongated inserts are disposed between the vertical outer wall members and are configured to form at least one longitudinally extending channel in the web member; and

[0031] A cover engages the upper edge of the vertical wall members and encloses the metal inserts in the space between the first and second vertical wall members.

[0032] Claim 16. The beam according to claim 15, wherein the elongated insert is made of metal.

[0033] Claim 17. The beam according to claim 15, wherein the cover is made of at least one of metal, composite material, and polymer.

[0034] Claim 18. The beam according to claim 15, wherein the non-conductive outer surface of the elongated vertical web member includes a fiberglass layer.

[0035] Claim 19. The beam according to claim 15, further comprising a plurality of surface features on the inner surface of the elongated vertical web member, the plurality of surface features increasing the turbulence of the fluid in at least one longitudinally extending channel in the web member. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The present disclosure is more fully understood from the detailed description and the drawings, wherein:

[0037] Figure 1 is a perspective view of a base of a composite cross member for an electric vehicle battery pack according to the principles of the present disclosure;

[0038] Figure 2 is a perspective view of first and second elongated outer vertical wall members and elongated metal inserts of a composite cross member for an electric vehicle battery pack according to the principles of the present disclosure;

[0039] Figure 3 is a perspective view of the first and second elongated outer vertical wall members, showing the structures on their inner surfaces for increasing turbulence;

[0040] Figure 4 is a perspective view of a cover of a composite cross member for an electric vehicle battery pack according to the principles of the present disclosure;

[0041] Figure 5 is a partial exploded view of a composite cross member for an electric vehicle battery pack according to the principles of the present disclosure;

[0042] Figure 6 is a vertical end view of a composite crossbeam for an electric vehicle battery pack according to the principles of the present disclosure;

[0043] Figure 7 is a vertical cross-sectional view of a composite crossbeam for an electric vehicle battery pack according to the principles of the present disclosure, showing a first possible arrangement of longitudinal fluid cooling channels;

[0044] Figure 8 is a vertical cross-sectional view of a composite crossbeam for an electric vehicle battery pack according to the principles of the present disclosure, showing a second possible arrangement of longitudinal fluid cooling channels;

[0045] Figure 9 is a vertical cross-sectional view of a composite crossbeam for an electric vehicle battery pack according to the principles of the present disclosure, showing a third possible arrangement of longitudinal fluid cooling channels; and

[0046] Figure 10 is a vertical cross-sectional view of a composite crossbeam for an electric vehicle battery pack according to the principles of the present disclosure, showing a fourth possible arrangement of longitudinal fluid cooling channels. DETAILED DESCRIPTION

[0047] Embodiments of the present disclosure provide a composite crossbeam for an electric vehicle battery pack. The crossbeam is disposed transversely in battery backs to support prismatic battery packs disposed within the battery pack. The battery packs are supported by adjacent crossbeams, which also aids in cooling the battery pack.

[0048] According to one such embodiment of the present disclosure, there is provided a beam 20 ( Figure 6 ) for supporting a plurality of prismatic battery packs in a battery pack housing of an electric vehicle. The beam 20 may include a base 22 having a lower elongate horizontal flange 24 and an upper elongate horizontal flange 26 that is narrower than the lower elongate horizontal flange, and spaced apart and generally centered above the lower elongate horizontal flange by a web 28.

[0049] The base 22 is preferably made of a carbon fiber composite material to make the base strong, lightweight, and substantially non-conductive, and substantially non-reactive to the battery pack components supported on the beam.

[0050] The web member 30 can be disposed on the upper elongated horizontal flange 26 of the base 22. The web member 30 can be fixed to the base 22, for example, by thermal welding or other suitable means. The web member 30 can have first and second elongated outer vertical wall members 32 and 34, which have upper edges 36, 38 and lower edges 40, 42 respectively. The lower edges 40, 42 can have outwardly projecting flanges 44, 46 projecting therefrom. These flanges 44, 46 can be supported on and fixed to the base 22. As discussed in more detail below, the inner surfaces of the elongated outer vertical wall members 32 and 34 can have features 48 formed therein.

[0051] The first and second elongated outer vertical wall members 32 and 34 can be made of a reinforced polymer composite material, such as a thermoplastic resin reinforced with carbon fiber, glass fiber, high-strength polymer fiber or other suitable materials. The fibers can be unidirectional fibers, woven fibers or chopped fibers. The filler can also be particles or flakes. At least the outer surfaces of the wall members 32 and 34 are non-conductive. The first and second elongated outer vertical wall members 32 and 34 can comprise about 35% to about 50% fiber reinforcement material, and in some embodiments, at least about 80% of the fibers in the first and second elongated outer vertical wall members are oriented parallel to the longitudinal direction.

[0052] At least two elongated metal inserts 50 and 52 can be disposed between the vertical outer wall members 32 and 34 and configured to form at least one longitudinally extending channel 54 therebetween for the circulation of a cooling fluid. The metal inserts 50 and 52 are preferably made of aluminum, copper or other suitable thermally conductive metal or metal alloy.

[0053] In some embodiments, at least two metal inserts 50 and 52 can be bonded to one of the elongated outer vertical wall members 32 and 34. In other embodiments, at least two metal inserts 50 and 52 can be molded into one of the elongated outer vertical wall members 32 and 34.

[0054] The cover 56 can engage the upper edges 36, 38 of the outer vertical wall members 32 and 34 and enclose the metal inserts 50 and 52 in the space between the first and second outer vertical wall members.

[0055] The first and second elongated outer vertical wall members can comprise about 35% to about 50% fiber reinforcement material, and in some embodiments, at least about 80% of the fibers in the first and second elongated outer vertical walls are oriented parallel to the longitudinal direction. In some embodiments, each elongated outer vertical wall member 32 and 34 has a thickness of about 0.75 to about 1 mm and a thermal conductivity of about 0.4 to about 0.8 W / mK. In other embodiments, each elongated outer vertical wall member 30 and 34 has a thickness of about 1.5 mm and a thermal conductivity of about 0.8 to about 1.2 W / mK.

[0056] In some embodiments, a fiberglass layer between each metal insert and its respective elongated outer vertical web member. A plurality of surface features 48 may be present on the inner surface of the elongated vertical web member, and the plurality of surface features 48 increase the turbulence of the airflow in the space between the elongated vertical wall members.

[0057] A beam 20 may be formed with a channel 54 that allows a cooling fluid (liquid or gas) to circulate between battery packs in contact with the beam. For example, as Figure 7 shown, Figure 7 is a vertical cross-sectional view of one embodiment of a composite crossbeam for an electric vehicle battery pack according to the principles of the present disclosure. Channels 54A and 54B are formed adjacent to the inner walls of the elongated outer vertical wall members 32 and 34. As described above, the surface features 48 on the inner surfaces of the elongated outer vertical wall members 32 and 34 can increase the turbulence and heat transfer of the fluid in channels 41A and 54B.

[0058] As Figure 8 shown, Figure 8 is a vertical cross-sectional view of another embodiment of a composite crossbeam for an electric vehicle battery pack according to the principles of the present disclosure. Channels 54C and 54D are formed adjacent to the inner walls of the elongated outer vertical wall members 32 and 34. As described above, the surface features 48 on the inner surfaces of the elongated outer vertical wall members 32 and 34 can increase the turbulence and heat transfer of the fluid in channels 54C and 54D.

[0059] As Figure 9 shown, Figure 9 is a vertical cross-sectional view of another embodiment of a composite crossbeam for an electric vehicle battery pack according to the principles of the present disclosure. Channels 54E and 54F are formed adjacent to the inner walls of the elongated outer vertical wall members 32 and 34. As described above, the surface features 48 on the inner surfaces of the elongated outer vertical wall members 32 and 34 can increase the turbulence and heat transfer of the fluid in channels 54E and 54F.

[0060] As Figure 10 shown, Figure 10 is a vertical cross-sectional view of another embodiment of a composite crossbeam for an electric vehicle battery pack according to the principles of the present disclosure. Channels 54G and 54H are formed adjacent to the inner walls of the elongated outer vertical wall members 32 and 34. As described above, the surface features 48 on the inner surfaces of the elongated outer vertical wall members 32 and 34 can increase the turbulence and heat transfer of the fluid in channels 54G and 54H.

[0061] In addition to supporting the battery pack, the assembled beams 20 increase the structural integrity of their incorporation into the battery pack housing. In contrast, the beams 20 provide a significant weight reduction compared to metal beams and, due to their composite structure, eliminate the need for a separate insulation coating. However, the composite material preferably has sufficient flexibility to accommodate the expansion of the battery pack during its lifetime. In addition, the beams provide cooling channels 54 to help maintain the battery pack supported by the beams within its desired operating temperature range.

Claims

1. A beam for supporting a plurality of prismatic battery packs in a battery pack housing of an electric vehicle, the beam comprising: A base having a lower elongated horizontal flange and an upper elongated horizontal flange, the upper elongated horizontal flange being narrower than the lower elongated horizontal flange and spaced above and generally centered over the lower elongated horizontal flange by a vertical web; A web member disposed on the upper elongated horizontal flange of the base, the web member including first and second elongated outer vertical wall members, the web member having an upper edge and a lower edge, wherein the lower edge engages the base; at least two elongated inserts are disposed between the vertical outer wall members and configured to form at least one longitudinally extending channel for cooling fluid in the web member.

2. The beam according to claim 1, further comprising a cover that engages the upper edge of the vertical wall members and encloses the inserts in a space between the first and second elongated outer vertical wall members.

3. The beam according to claim 1, wherein the base is made of a carbon fiber composite material.

4. The beam according to claim 1, wherein the first and second elongated vertical wall members are made of a carbon fiber composite material.

5. The beam according to claim 1, further comprising a fiberglass layer on the outer surfaces of the first and second elongated vertical wall members.

6. The beam according to claim 1, wherein the elongated inserts are made of metal.

7. The beam according to claim 1, further comprising a plurality of surface features on the inner surface of the elongated vertical web member, the plurality of surface features increasing the turbulence of the cooling fluid in the channel formed between the elongated inserts and the elongated vertical wall members.

8. The beam according to claim 1, wherein at least the outer surface of each elongated outer vertical wall member is non-conductive.

9. The beam according to claim 8, wherein each elongated outer vertical wall member has a thickness of about 0.75 to about 1 mm and a thermal conductivity of about 0.4 to about 0.8 W / mK.

10. The beam according to claim 8, wherein each elongated outer vertical wall member has a thickness of about 1.5 mm and a thermal conductivity of about 0.8 to about 1.2 W / mK.

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