Electric vehicle battery assembly housing

Abstract

Battery assembly housing comprising: a tub; a lid attached to the tub to provide an interior therebetween; and a plurality of molded retention features to secure an internally housed battery assembly, wherein the retention features comprise a flange defining an opening, the flange being deflected to receive a tab within the opening when the battery assembly is installed therein.

Description

The present disclosure generally relates to a housing for a battery assembly of an electric vehicle.Electric vehicles are generally distinct from conventional motor vehicles because electric vehicles are selectively propelled using one or more battery powered electric machines. Conventional motor vehicles, in contrast, are based solely on an internal combustion engine for propelling the vehicle. Electric vehicles may use electric machines instead of or in addition to the internal combustion engine.Example electric vehicles include hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), fuel cell vehicles, and battery electric vehicles (BEVs). A powertrain of an electric vehicle is typically equipped with a battery that stores electrical energy for energizing the electric machine. Packaging battery assemblies within electric vehicles may be difficult.The prior art relating to battery housings and their attachment to a vehicle is described in the documents DE 695 09 620 T2, WO 2005 / 105 589 A1, DE 10 2009 009 700 A1 and U.S. Pat. No. 5,806,618 A.A battery assembly case according to an embodiment of the present disclosure includes, among other things, a tray and a lid fixed to the tray to provide an interior therebetween. A plurality of retention features secure a battery assembly received within the interior.In an example of the above housing, the retention features are molded together with the lid or tray.The retention features include a flange defining an opening. The flange deflects to receive a tab within the opening when the battery assembly is installed inside.In another example of any of the above housings, the tray, lid, or both are made of thermoplastic.In another example of any of the above housings, the lid is welded to the tub.In another example of any of the above housings, a connecting wall extends from the tray, lid, or both into the interior. The connecting wall separates a serviceable area of the interior from a non-serviceable area.In another example of any of the above housings, the tray includes corrugations that deflect when the battery assembly is positioned inside.In another example of any of the above housings, the interior is oversized relative to the battery assembly when the battery assembly is outside the interior such that the tray and lid compress the battery assembly when the battery assembly is inside.In another example of any of the above housings, an assembly includes the housing and the assembly includes a battery assembly inside the housing. The battery assembly is secured relative to the tray and the lid using molded fasteners only.A housing according to another exemplary aspect of the present disclosure includes, among other things, a tray and a lid attached to the tray to provide an interior therebetween that houses an assembly. The interior is configured to be oversized relative to the assembly such that the tray and lid compress the assembly received within the interior. A plurality of retention features are formed together with the lid or tray. The plurality of retention features secure the internally received assembly.In an example of the above housing, the assembly is a battery assembly of an electric vehicle.The retention features include a flange defining an opening. The flange deflects to receive a tab within the opening when the assembly is installed inside.In another example of any of the above housings, the tray, lid, or both are made of thermoplastic.In another example of any of the above housings, the lid is welded to the tub.In another example of any of the above housings, a connecting wall extends from the tray, lid, or both into the interior. The connecting wall separates a serviceable area of the interior from a non-serviceable area.In another example of any of the above housings, the tray includes corrugations that deflect when the assembly is positioned inside.A method according to yet another exemplary aspect of the present disclosure includes, among other things, securing an assembly within an electric vehicle housing by compressing the assembly between a lid and a tray. The lid, the tray, or both are deflected during attachment. The housing includes a plurality of retention features to secure a battery assembly received within the interior. The retention features include a flange defining an opening. The flange deflects to receive a tab within the opening when the battery assembly is installed inside.In another example of the above method, the assembly is a battery assembly. The lid, the tray or both are made of thermoplastic.In another example of any of the above methods, the method includes securing the assembly to the lid and the tray using molded fasteners.In another example of any of the above methods, the method includes supporting the electric vehicle housing with a strap attached to the electric vehicle.The embodiments, examples and alternatives of the preceding paragraphs, the claims, or the following description and drawings, including any of their various aspects or respective individual features, may be taken independently or in any combination. Features described in connection with an embodiment may be applied to all embodiments, provided such features are not incompatible.The various features and advantages of the disclosed examples will become apparent to those skilled in the art from the detailed description. The figures accompanying the detailed description may be briefly described as follows: FIG. 1 illustrates a highly schematic view of an electric vehicle having an example housing that houses a battery assembly. FIG. 2 is a partially cut-away perspective view of another example housing that houses an electric vehicle battery assembly. FIG. 3 shows a trough of the housing of FIG. 2. FIG. 4 is an enlarged perspective view of an interface between a lid and a tray of the housing. FIG. 5 is a sectional view taken along line 5- 5 in FIG. 3. FIG. 6 is an enlarged perspective view of a retention feature of the housing in an engaged position with a battery assembly. FIG. 7A shows an enlarged sectional view of the retention feature taken along line 7- 7 in FIG. 2. FIG. 7B shows an enlarged cross-sectional view of the retention feature taken at line 7- 7 in FIG. 2 when the retention feature is in a bent position. FIG. 8 shows an enlarged view of a cold plate of a battery assembly mounted to the tray of FIG. 3. FIG. 9 is a side sectional view taken on line 7--7 of FIG. 2 with the battery assemblies removed from the housing. FIG. 10 is a side view taken along line 7- 7 in FIG. 2 with battery assemblies received within the housing. FIG. 11 is a partial cross-sectional view of another exemplary retention feature. FIG. 12 is a partial cross-sectional view of another exemplary retention feature. FIG. 13 is a partial cross-sectional view of the retention feature of FIG. 12 in an installed position. FIG. 14 shows a perspective view of example straps to support the housing of FIGS. 2-10. FIG. 15 is a perspective view of the belts coupled to the housing of FIGS. 2-10.Referring to FIG. 1, an example electric vehicle 10 includes a powertrain 14 having at least a battery assembly 18 and an electric machine 22. the example electric vehicle 10 is a hybrid electric vehicle (HEV), however, it should be understood that the concepts described herein are not limited to HEVs and could be extended to other electrified vehicles, including but not limited to plug-in hybrid electric vehicles (PHEVs) and battery vehicles (BEVs).The example electric machine 22 includes an electric motor and a separate generator. Other examples may include a combined motor / generator.In one embodiment, the powertrain is a power split powertrain system that uses a first drive system and a second drive system. The first drive system includes a combination of an internal combustion engine (not shown) and the electric machine 22. The second drive system includes at least the electric machine 22 and the battery assembly 18. The first and second drive systems generate torque for driving one or more sets of vehicle drive wheels.The battery assembly 18 is an example type of electric vehicle battery assemblies. The battery assembly 18 may take the form of a high voltage battery that may output electrical power to operate the electric machine 22. Other types of energy storage devices, output devices, or both may be used with the electric vehicle 10. During some operating modes, the electric machine 22 charges the battery assembly 18. Generally, the battery assembly 18 includes sidewalls, end plates, a cold plate, spacers, battery cells, and related components.In this example, the battery assembly 18 is housed within an interior of a battery assembly housing 30. The battery assembly 18 and the housing 30 are located outside the electric vehicle 10. The housing 30 holds and protects the battery assembly 18 and other related components.Straps 36 attached to the floor panel 34 support the housing 30 of the battery assembly 18.The example battery housing 30 includes a tray 40 and a lid 44. Some examples of thermoplastic materials that could be used include high density polyethylene or polypropylene. Plastics could be used which are relatively soft and deformable.In another example, the tray 40 or cover 44 is a rigid material and the other of the tray 40 or cover 44 is compliant.Alternatively, a compliant non-polymeric material such as spring steel could be used for the housing (allowing spring loaded compression of the battery assembly 18 against the vehicle body).In this example, the lid 44 has a contour for engaging a contour of the floor panel 34, whereby the lid 44 and the housing 30 can closely conform to the floor panel 34. The contours may also help align the housing 30 with the floor panel 34 during assembly.The tray 40 and lid 44 are attached to each other at an interface 48 via vibration welding, ultrasonic welding, laser welding, mirror welding, or any other method of joining primary polymeric structures. These joining techniques fuse the tray 40 to the lid 44 to prevent contaminants from entering the housing 30.Notably, the example tray 40 is secured to the interface 48 on the lid 44 without mechanical fasteners such as bolts, screws, etc. The attachment method also does not require an attachment flange that extends laterally from the tray 40 or the lid 44 to provide a region for engaging the mechanical attachments. Eliminating a fastener flange saves packaging space.The tray 40 includes a plurality of corrugations 54. the housing 30 is oversized relative to the battery assembly 18 such that the corrugations 54 flex or deflect when the battery assembly 18 is installed inside the housing 30. The flexing corrugations 54 may help absorb shocks when the electric vehicle 10 is driven. The corrugations 54 flex to absorb these shocks. The corrugations 54 also provide good thermal contact to a floor of the battery assembly 18, The corrugations 54 may similarly flex and absorb loads transferred from stones thrown up by the vehicle wheels, or loads from road surfaces (tempo bumps) or road break-up (any foreign object).In another example, the housing 30 compresses the battery assembly 18 when mounted to a vehicle. In such an example, portions of the housing 30 press against the battery assembly 18 due to attachment to the vehicle structure.In this example, a height of the interior of the housing 30 without the battery assembly 18 is less than a height of the interior with the battery assembly 18 housed in the housing 30, and thus, when the battery assembly 18 is housed within the housing 30, the battery assembly 18 presses against the tray 40 and the lid 44, causing portions of the housing 30 to flex. These portions may be the corrugations 54 and may additionally or alternatively be the top of the lid 44 or side walls developed by the cover and tray. This results in the housing exerting a compressive force on the battery assembly 18 and helps to secure the battery assembly 18 within the housing 30.The example housing 30 will be described in connection with an electric vehicle 10. In other examples, the housing could be used to house relatively heavy batteries in other applications such as an aircraft. Other elements could be housed in the housing instead of or in addition to the batteries. Other possible elements include power supplies, electrical control modules, and so forth.Referring now to FIGS. 2-8, with continued reference to FIG. 1, another example housing 130 includes a plurality of serviceable portions 72 and a non-serviceable portion 74. The wall 76 may be formed in whole or in part with a trough 140 or a cover 144. The wall 76, the tray 140, and the lid 144 are a thermoplastic material in this example.The tray 140 and lid 144 are secured together at an interface 148. The tray 140 and lid 144 may have complementary vertically extending flanges 150 and 152 near the interface 148. During attachment of the tub 140 to the lid 144, the flanges 150 and 152 may aid in positioning, for example.A thermosetting or any other engineering resin or combination of two or more polymeric materials or other resilient, flexible materials such as spring steel could also be used to form the wall 76, the tray 140, the lid 144, or any combination thereof in whole or in part.A battery electric control module (BECM) and a bused electrical center (BEC) may be housed within the serviceable portion 72. The battery assemblies 18 are housed in the non-serviceable portion 74. Transverse wall connections 84 may be molded into wall 76 or other areas to electrically and thermally connect serviceable portions 72 and non-serviceable portions 74 to one another and to areas outside of housing 130.The exemplary transverse wall 84 includes a flanged passage 88 that receives a hose 90. The flanged bushing is plastically overmolded and secured to the wall 76 via plastic welds 92 (FIG. 5 ). A flange 94 of the flanged passage 88 is located in the non-serviceable portion 74.The housing 130 may include one or more lids, such as pull-off lids, to allow a technician to access the serviceable portions 72 of the housing 130 when the tray 140 is attached to the lid 144. The wall 76 prevents the technician from obtaining access to the non-serviceable portion 74, and more specifically the battery assemblies 18, when the technician waits for components housed within the serviceable portions 72.The housing 130 is configured to compress the battery assemblies 18 within the non-serviceable portion 74. The housing 130 includes additional features for securing one or more of the battery assemblies 18 within an interior provided between a tray 140 and a lid 144. For example, the tray 140 of the housing 130 includes a plurality of retention features 58.The example retention features 58 are loop-and-tab mating-type features that include a flange 62 that extends upwardly from the tray 140. The flange 62 defines an opening 66. the tray 140 includes corrugations 54 for positioning under battery assemblies 18. the flange 62 is laterally between two different groups of the corrugations 54. in other examples where two different battery arrays are not used, the flange 62 is laterally outside of the corrugations 54.When the battery assembly 18 is installed within the housing 130, a tab 70 of the battery assembly 18 extends through the opening 66 of the flange 62. the flange 62 may flex laterally outward in a direction F (FIG. 7B ) to allow movement of the tab 70 downward to a position aligned with the opening 66.The example flange 62 is formed with the tub 140. The flange 62 that is formed can flex better to receive the battery assembly 18 during installation than, for example, a steel flange.In this example, flange 62 is a loop of plastic and tab 70 is metallic. In another example, the design could use a locking tab or metal or plastic that receives a reciprocal locking tab or loop of metal or plastic, or the plastic could also be a reciprocal locking tab rather than a loop.The tray 140 also includes lips 64 formed with the tray 140. The lips 64 prevent the battery assemblies 18 from laterally displacing within the housing 130. In this example, the lips 64 alternate with the flanges 62 along the length of the battery assemblies 18.The lid 144 may also include features for securing the battery assembly 18. For example, the lid 144 includes a plurality of molded recesses 78. the recesses 78 extend downwardly to contact an upwardly facing surface of the battery assembly 18 in an installed position.In this example, at least one of the recesses 78 bextends between two laterally adjacent battery assemblies 18 to block lateral movement of the battery assembly 18 within the housing 130. There are also depressions 78a along the top, front and rear edges of the cover along the array which block lateral movement of the front and rear battery assemblies in the forward and rearward directions, respectively.The example housing 130 includes an interior that is oversized relative to the battery assemblies 18. Thus, when the battery assembly 18 is installed, the corrugations 54 under the battery assemblies 18 may flex and deflect. Also, some of the depressions 78 in the lid 144 may flex and deflect due to the under-sized interior.The corrugations 54 may reinforce the tub 140. Additionally, corrugations 54 could be used to support cooling tubes 156 that communicate coolant for cooling battery assembly 18. The cooling tubes 156 may be in direct contact with cold plates 160 (FIG. 8 ) of the battery assembly 18 to facilitate thermal communication. Extensions of the tray may be received in an opening in the cold plate 160 or vice versa to stabilize the cold plate 160.FIG. 9 shows an interior of the example housing 130 prior to installation of the battery assemblies 18.FIG. 10 shows the battery assembly case 130 with two battery assemblies 18 installed inside, The battery assemblies 18 effectively increase a height of the inside to a distance H 2, which is greater than the distance H 1. The battery assembly 18 is thus compressed between the tray 140 and the lid 144. The compression facilitates stabilizing the battery assemblies 18 relative to the housing 130. The compression is effectively a spring force applied by the housing 130 to the battery assemblies 18.Retaining features other than the plug-type retaining features 58 may be used. Referring to FIG. 11, another example battery assembly 18' may include an extension 80 that is received within a pocket 82 formed in a tray 140'. The extension includes an enlarged end 86 that is captured within the tapered walls defining the pocket 82. When the extension 80 is inserted into the pocket 82, the walls flex outwardly to receive the enlarged ends 86.Another extension (not shown) may extend upwardly from the battery assembly for receipt within a pocket of a lid.Referring now to FIGS. 12 and 13, another exemplary battery assembly 18" is retained within a tray 240 and a lid 244 of a housing 230 with a retaining wedge 99. In this example, a wall 101 of the lid 244 includes an inwardly facing edge with teeth 103. The retention wedge 99 includes teeth 105.During assembly, wedge 99 is moved in a direction D to wedge firmly between battery assembly 18" and wall 101. The movement biases the wall 101 outward. In this position (FIG. 12 ), the wedge 99 prevents lateral movement of the battery assembly 18" relative to the housing 230. The teeth 103 contact the teeth 105 to prevent withdrawal of the tool 99 in a direction opposite to the direction D.The wedge 99 includes a first end having a receptacle 107 for receiving a swaging tool used to force the wedge 99 into the installed position of FIG. 12. The first end is tapered towards a second end 111. The taper facilitates movement of the wedge 99 to the installed position. The taper also provides a biasing pressure between the wall 101 and the battery assembly 18''.Other retention features may include male hooks, ears, Bowden cable fasteners, and so forth.The example housing 130 is secured to a floor panel with one or more straps. The tray 140 in this example includes an integrally molded trough 96 that receives the strap and helps stabilize the positioning of the strap relative to the housing. The belts could be woven sheet material or solid steel, for example. Web belts may be coated or overmolded with a thermoplastic resin to prevent cut wound and exposure to the environment.Referring to FIGS. 14 and 15, a plurality of straps 136 are used in conjunction with the housing 130. The belts 136 may have ends looped back upon themselves. The strap 136 includes a collar 98 positioned along a portion of the strap 136. Collar 98 may be made of a polymer that provides a non-abrasive, non-sharp surface to housing 130. The collar 98 may include a flange 100 that provides a fastener engaging surface for securing the strap 136 to the housing 130. The flange 100 may couple directly to walls of the well 96. The collar 98 may be over-molded using high density polyethylene or protected with a non-steel sleeve, for example. The strap 136 may further be at least partially molded into the tray 140 or another portion of the battery housing 130.The strap 136 is configured to exert a compressive force against the housing 130 when installed. The strap 136 may be made short to cause an interference fit between the housing 130 and a floor panel of the vehicle when the strap 136 is fastened. The interference fit may improve retention and reduce a perceived design gap between the housing and the floor panel.Features of the disclosed examples include protecting a battery assembly or other type of assembly with a housing with a reduced number of components and fasteners as prior art designs. The package has reduced manufacturing process cycle time, increased mikroability for a relatively complex design, and reduced weight compared to other designs.In some examples, the housing absorbs impact energy to increase collision capability and creates effective resistance to stonechip, ground contact, water ingress, and other environmental noise.The example housing may have a narrower package bottom surface and increased energy density with respect to designs that require flanges for mechanical fasteners, separate gaskets, etc. The example package may further have a relatively improved package-body contact, which provides improved packaging density without adversely impacting performance and NVH targets.

Claims

A battery assembly housing comprising: a tray; a lid secured to the tray to provide an interior therebetween; and a plurality of molded retention features to secure a battery assembly received within the interior, the retention features comprising a flange defining an opening, the flange deflected to receive a tab within the opening when the battery assembly is installed within the interior.The housing of claim 1, wherein the retention features are formed together with the lid or the tray.The housing of claim 1, wherein the tray, the lid, or both are made of thermoplastic.The housing of claim 3, wherein the lid is welded to the tray.The housing of claim 1, comprising a connecting wall extending from the tray, the lid, or both into the interior, the connecting wall separating a serviceable area of the interior from a non-serviceable area.The housing of claim 1, wherein the tray includes corrugations that deflect when the battery assembly is positioned internally.The housing of claim 1, wherein the interior is oversized relative to the battery assembly when the battery assembly is outside the interior such that the tray and lid compress the battery assembly when the battery assembly is inside.An assembly comprising the battery assembly housing of claim 1, further comprising a battery assembly within the interior, wherein the battery assembly is secured relative to the tray and the lid using molded fasteners only.A housing comprising: a tray; and a lid secured to the tray to provide an interior therebetween for receiving an assembly, the interior being configured to be oversized relative to the assembly such that the tray and the lid compress the assembly housed inside; and a plurality of retention features formed together with the lid or the tray, the plurality of retention features securing the assembly housed inside, the retention features comprising a flange defining an opening, the flange deflected to receive a tab within the opening when the assembly is installed inside.The enclosure of claim 9, wherein the assembly is a battery assembly of an electric vehicle.The housing of claim 9, wherein the tray, the lid, or both are made of thermoplastic.The housing of claim 9, wherein the lid is welded to the tray.The housing of claim 9, comprising a connecting wall extending from the tray, the lid, or both into the interior, the connecting wall separating a serviceable area of the interior from a non-serviceable area.The housing of claim 9, wherein the tray includes corrugations that deflect when the assembly is positioned internally.A method comprising: securing a battery assembly within an electric vehicle housing by compressing the battery assembly between a lid and a tray, wherein the lid, the tray, or both are deflected during the securing, wherein the housing comprises a plurality of molded retention features to secure an internally received battery assembly, wherein the retention features comprise a flange defining an opening, wherein the flange is deflected to receive a tab within the opening when the battery assembly is installed internally.The method of claim 15, wherein the lid, the tray, or both are of thermoplastic.The method of claim 15, further comprising securing the battery assembly to the lid and the tray using molded fasteners.The method of claim 15, further comprising supporting the electric vehicle housing with a strap attached to the electric vehicle.

Images