Battery pack housing assembly for electric and hybrid vehicles using a plastic composite material and method for producing the same

Abstract

Battery pack housing assembly for an electric vehicle, comprising: a housing body (200) for accommodating a battery pack (300); and a cover (100) detachably coupled to the housing body (200), wherein the housing body (200) is formed from a plastic composite material in which a long fiber or a mixture of a long fiber and a continuous fiber is used as a reinforcing fiber in a plastic matrix, a first separate reinforced element (212) connected to one or more side support parts (211) of the housing body (200), wherein the first separate reinforced element (212) is formed from a plastic composite material in which a long fiber, a continuous fiber, or a mixture of a long fiber and a continuous fiber is used as the reinforcing fiber in a plastic matrix, and a second separate reinforced element (220a, 220b) having a planar shape, which is arranged on an underside of the housing body (200), wherein the second separate reinforced element (220a, 220b) is formed from a plastic composite comprising a continuous fiber as a reinforcing fiber in a plastic matrix, wherein the housing body (200) is formed integrally with the second separate reinforced member (220a, 220b) by an extrusion press molding apparatus, and the bottom of the housing body (200) is formed in a single-layer structure.

Description

BACKGROUND(a) Technical field

[0001] The present invention relates to a battery pack housing assembly particularly suitable for electric and hybrid vehicles, and to a method for manufacturing a battery pack housing assembly. More particularly, it relates to a battery pack housing assembly for electric and hybrid vehicles formed at least partially from a plastic composite material, and to a method for manufacturing the same, which has reduced weight and improved structural rigidity, dimensional stability, and collision characteristics. (b) State of the art

[0002] Given rising oil prices and CO 2Regulations, recent studies have focused on the development of environmentally friendly vehicles that can replace typical internal combustion engine vehicles. Some vehicle manufacturers have already achieved success in marketing and introducing pure electric vehicles and hybrid vehicles into the market.

[0003] As in Fig. As shown in Figure 1, electric vehicles and hybrid vehicles include a battery 1 located in the lower portion of the vehicle body or in the trunk for supplying electric power to an electric motor. The high-voltage battery 1, used as the main power source in electric vehicles and hybrid vehicles, has a general arrangement in which a housing assembly houses a plurality of battery packs.

[0004] As in Fig. 2, a typical battery pack housing assembly includes a lower housing body 200 for housing a plurality of battery packs 300, a cover 100 that can be arranged to cover and couple the top of the lower housing 200, and various types of structural reinforcement members (e.g., cross members, side members, etc.). The battery pack housing assembly may further house additional associated parts, such as a battery management system (BMS) and a fan, in addition to the battery pack 300.

[0005] Since the distance to empty (DTE) of electric vehicles is inversely proportional to the vehicle's weight, weight reduction has become increasingly important in electric vehicle development. Consequently, active efforts are being made to use lightweight materials for various electric vehicle components.

[0006] For example, one attempt is being made to replace typical metallic materials commonly used to form battery pack casings with a plastic composite material. Since the top cover largely does not support the battery load, the top cover can be manufactured using a typical plastic composite molding process. However, since the bottom casing and structural reinforcement elements of the casing must be able to adequately support the battery load, these structures have been manufactured by separately press-molding steel parts or incorporating a steel-reinforced material into a plastic composite.

[0007] However, the steel materials used for the lower housing and structural reinforcement members of the battery pack housing assembly must be of sufficient thickness to ensure rigidity and durability, and parts such as brackets must be assembled separately. As a result, the overall weight of the battery pack housing assembly increases.

[0008] Mounting arrangements in the lower vehicle body floor for a battery pack housing assembly are described in EP 1950070 A1, EP 1939028 A1, EP 1939027 A1, EP 1939025 A1, US 2009 / 0236162 A1, US 7610978 B2 and JP 2009-137408 A. To increase rigidity, these either use a plastic composite material in which a steel frame is inserted or employ a structure in which a separate cross member formed from a steel material is coupled, followed by installation into a vehicle body cross member and a side member.

[0009] However, such battery pack housing assemblies formed with a steel material increase the weight of the vehicle body, particularly due to the use of numerous steel parts. As such, the overall weight increases, which reduces the DTE.

[0010] Furthermore, large thermoplastic parts such as the lower housing of the battery pack assembly are susceptible to shrinkage and / or deformation due to forming conditions, and subsequent stresses may also be caused by residual stresses due to repeated shrinkage and expansion with temperature fluctuations during use.

[0011] Thus, a method for improving the dimensional accuracy of parts while reducing weight using a plastic composite material is urgently needed.

[0012] From US 2011 / 0 294 000 A1, a battery pack housing assembly for an electric vehicle is known, comprising: a housing body for accommodating a battery pack; and a cover detachably coupled to the housing body, wherein the housing body is formed from a plastic composite material in which a long fiber or a mixture of a long fiber and a continuous fiber is used as a reinforcing fiber in a plastic matrix, and a separate reinforced element connected to one or more side support parts of the housing body, wherein the separate reinforced element is formed from a plastic composite material in which a long fiber, a continuous fiber or a mixture of a long fiber and a continuous fiber is used as the reinforcing fiber in a plastic matrix.

[0013] DE 10 2010 013 131 A1 discloses a method for producing continuous fiber-reinforced molded parts made of thermoplastics from a three-dimensional preform, as well as a molded automotive part. By preforming unidirectional fiber-reinforced mats into a three-dimensional preform, the molded part essentially does not need to undergo any forming or flow processes in the subsequent consolidation step.

[0014] JP H09 - 207 233 A describes the provision of a vehicle step, a roof rack leg, and a battery tray which have excellent weather resistance in terms of color, strength, etc., and other various properties, and are suitable for outdoor use for a long period of time. At least the main parts of a step, a roof rack leg, and a battery tray are formed from a long glass fiber reinforced polyolefin composition comprising (A) a long glass fiber reinforced polyolefin resin pellet having 15-75 wt.Glass fiber content, wherein a glass fiber bundle is impregnated with a resin, while a resin-reinforcing continuous glass fiber is drawn out in a polyolefin resin, cut to obtain a pellet having a length of 2-100 mm in the fiber direction, and the glass fiber aligns in parallel with the actual same length as that of the pellet, (B) a polyolefin resin, (C) an antioxidant, (D) a light stabilizer, and (E) an ultraviolet absorber.

[0015] DE 10 2006 048 291 A1 provides a support tray, in particular for receiving and holding a battery for a motor vehicle, in particular a truck, which is designed as a fiber-reinforced plastic part and comprises fastening points for attachment to the motor vehicle, wherein the support tray is made of a pre-impregnated fiber-matrix semi-finished product, in particular a thermoplastic semi-finished product, which is reinforced at least locally with at least one insert.

[0016] Finally, DE 39 16 342 A1 also shows a protective device for a vehicle battery with a reinforcing layer arranged between the vehicle body and the battery, wherein the reinforcing layer is a plastic mat whose structure has fibers whose dimensions and strength are designed such that the fibers wrap around the drill bit of a drill penetrating the plastic mat when drilling into the plastic mat.

[0017] The above information disclosed in this Background section is intended only to enhance the understanding of the background of the invention and may therefore contain information that does not constitute prior art already known to a person skilled in the art in this country. SUMMARY OF REVELATION

[0018] It is therefore the object of the present invention to provide a battery pack housing assembly for a vehicle, in particular an electric or hybrid vehicle, which is formed at least partially from a plastic composite material, and a method for manufacturing the same. The present invention is intended to provide a reduction in weight while simultaneously improving structural rigidity, collision characteristics, and dimensional stability by using a lightweight plastic composite material for the housing.

[0019] The object is achieved by a battery pack housing arrangement having the features of claim 1 and a method having the features of claim 15. Advantageous further developments can be found in the subclaims.

[0020] In one aspect, the present invention provides a battery pack housing assembly for an electric vehicle, comprising: a housing body for receiving a battery pack; and a cover detachably coupled to the housing body, wherein the housing body is formed from a plastic composite material in which a reinforcing fiber is provided in a plastic matrix, and a first separate reinforced member connected to one or more side support parts of the housing body and formed from a plastic composite material in which a reinforcing fiber is provided in the plastic matrix.According to various embodiments, the reinforcing fiber used in the housing body is a long fiber or a mixture of a long fiber and a continuous fiber, and the reinforcing fiber used in the first separate reinforced member is a long fiber, a continuous fiber, or a mixture of a long fiber and a continuous fiber. Furthermore, a second separate reinforced member having a planar shape is provided, which is arranged on a bottom surface of the housing body. The second separate reinforced member is formed from a plastic composite comprising a continuous fiber as a reinforcing fiber in a plastic matrix. The housing body is integrally molded with the second separate reinforced member by an extrusion-compression molding device, and the bottom surface of the housing body is formed in a single-layer structure.

[0021] The long fibers that can be used in the housing element and the first separate reinforced element can be the same or different, the continuous fibers that can be used in the housing element and the first separate reinforced element can be the same or different, and the mixture of the long fiber and the continuous fiber that can be used in the housing element and the first separate reinforced element can be the same or different. Furthermore, the reinforcing element used in forming the housing body can be the same as the reinforcing element used in forming the first separate reinforced element (e.g.the reinforcing element for the housing body may be a long fiber, while the reinforcing element of the first separate reinforced element may be a continuous fiber; the reinforcing element for the housing body may be a first type of long fiber, while the reinforcing element of the first separate reinforced element may be a second type of long fiber, etc.). Alternatively, the reinforcing element used in forming the housing body may be different from the reinforcing element used in forming the first separate reinforced element.

[0022] In one embodiment, the long fibers of the housing body and the reinforced element have an aspect ratio of approximately 1000.

[0023] In another embodiment, the first separate reinforced element may be a bow-shaped reinforced element with a reinforcing rib. The first separate reinforced element may further include a structural region with a closed cross-section for absorbing collision energy when the side support part and the bow-shaped first separate reinforced element are coupled together.

[0024] In yet another embodiment, the first separate reinforced member may be formed in a sheet-like type (i.e., having a sheet-like structure) to be coupled to the two side brackets of the housing body.

[0025] In yet another embodiment, the continuous fiber of the second separate reinforced member disposed at the bottom of the housing may be arranged in a direction of the plastic matrix or may be secured in a form of woven fibers in which the continuous fibers cross in longitudinal and transverse directions.

[0026] In another embodiment, the continuous fiber is arranged in a direction that is longitudinal in a right and left width direction. The longitudinal direction of the continuous fiber may be orthogonal to a forward and backward longitudinal direction of the housing.

[0027] In a further aspect, the present invention provides a method of manufacturing a battery pack housing assembly for an electric or hybrid vehicle, comprising a housing body for receiving a battery pack and a cover removably coupled to the housing body, the method comprising: forming the housing body using a plastic composite material in which a reinforcing fiber is provided in a plastic matrix, wherein forming the housing body comprises: forming a first separate reinforced member using a plastic composite material in which a reinforcing fiber is provided in the plastic matrix, wherein the first separate reinforced member is connected to one or more side supports of the housing body;Forming a second separate reinforced element having a planar shape disposed on a bottom side of the housing body, the second separate reinforced element being formed from a plastic composite comprising a continuous fiber as a reinforcing fiber in a plastic matrix;and connecting the reinforced member to both side support parts of the housing body for coupling to a vehicle body, wherein the housing body is integrally molded with the second separate reinforced member by an extrusion press molding device, and the bottom of the housing body is formed into a single-layer structure. The reinforcing fiber of the housing body may be a long fiber or a mixture of a long fiber and a continuous fiber, and the reinforcing fiber of the separate reinforced member may be a long fiber, a continuous fiber, or a mixture of a long fiber and a continuous fiber. As described above, any type of long fiber, continuous fiber, and mixtures thereof may be provided in the housing body and the separate reinforced member.

[0028] In one embodiment, in forming the case body and the first separate reinforced member, an aspect ratio of a remaining long fiber may be equal to or greater than about 1000. What is meant by a "remaining" long fiber is the state of the reinforcing fiber itself in the case body as a result of (i.e., after) press molding, and thus may also be referred to as residual long fiber. Generally, many fibers are broken during injection molding, and the maximum length of residual glass fibers after such injection molding is 2~5 mm. However, according to the present invention, the maximum length of residual glass fibers is about 20 mm or more because most of the fibers remain intact without being broken after the molding process.

[0029] In a further embodiment, the forming of the first separate reinforced element may be performed such that the reinforced element has a bow-shaped configuration with at least one reinforcing rib. The first separate reinforced element may include a structural region with a closed cross-section for absorbing collision energy when the side support part of the housing body and the bow-shaped reinforced element are coupled together.

[0030] In yet another embodiment, the first separate reinforced member may be formed in a sheet-like type (i.e., having a sheet-like structure) to be coupled to both side support portions of the housing body.

[0031] In yet another embodiment, the method may further comprise: forming a second separate sheet-like reinforced member using a plastic composite material, wherein the plastic composite material comprises a continuous fiber as a reinforcing fiber in a plastic matrix; and disposing the sheet-like second separate reinforced member on a bottom side of the housing body.

[0032] In yet another embodiment, a unidirectional tape or a woven fiber woven with the continuous fibers may be used in forming the second separate sheet-like reinforced member.

[0033] In another embodiment, the unidirectional ribbon is used, and the continuous fiber can be arranged lengthwise in a right and left width direction orthogonal to a forward and backward longitudinal direction of the case body.

[0034] Further embodiments and embodiments of the invention are explained below. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The above and other features of the present invention will now be described in detail with reference to specific exemplary embodiments thereof shown in the accompanying drawings, which are given below by way of illustration only and thus are not limitative of the present invention, in which: Fig. 1 is a view showing a battery mounted in a vehicle; Fig. 2 is a view showing the structure of a battery for an electric vehicle in which a plurality of battery packs are accommodated by a battery pack case assembly; Fig. 3 to 5 are views illustrating a battery pack housing assembly according to an embodiment of the present invention, in which Fig. 3 is a perspective view showing a top side of a lower housing, Fig. 4 shows a perspective view illustrating a bottom side of the lower housing, and Fig. 5 shows a cross-sectional view taken along the line AA of Fig. 3 is taken; Fig. 6 is a perspective view showing a continuous fiber reinforced member used on a side support part of the lower housing according to an embodiment of the Fig. 3 to 5; Fig. 7 shows a cross-sectional view illustrating a continuous fiber reinforced member coupled to a side bracket of the lower housing according to an embodiment of the Fig. 3 to 5; Fig. 8 is a view showing a sheet-like continuous fiber reinforced member disposed on the underside of a lower casing according to another embodiment of the present invention; Fig. 9 is a view showing a sheet-like continuous fiber reinforced member having a large area disposed on the bottom surface of a lower case according to another embodiment of the present invention; Fig. 10 is a view illustrating a sheet-like continuous fiber reinforced member coupled to both side support members according to another embodiment of the present invention; and Fig. 11 is a view showing a sheet-like continuous fiber reinforced member coupled in plurality to both side support parts and the bottom of a lower case according to another embodiment of the present invention.

[0036] The reference numerals shown in the drawings include a reference to the following elements, as explained below: 100 top cover 200 lower housing (housing body) 211 Side bracket part 212 stirrup-like continuous fiber-reinforced or long fiber-reinforced element 213 Reinforcing rib 215a, 215b reinforcing rib 220a, 220b, 220c continuous fiber reinforced or long fiber reinforced element 300 battery pack

[0037] It should be understood that the accompanying drawings are not necessarily to scale and present a somewhat simplified representation of various preferred features intended to illustrate the principles of the invention. The specific constructional features of the present invention as disclosed herein, including, for example, specific dimensions, orientations, locations, and shapes, will be determined in part by the dedicated application and the operating environment.

[0038] In the figures, reference numerals refer to the same or equivalent parts of the present invention throughout the individual figures of the drawings. DETAILED DESCRIPTION

[0039] Reference will now be made in detail to the various embodiments of the present invention, examples of which are illustrated in the accompanying drawings and described below. While the invention will be described in connection with exemplary embodiments, it is to be understood that the present description is not intended to limit the invention to those exemplary embodiments. On the contrary, the invention is intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents, and other embodiments which may be included within the spirit and scope of the invention as defined by the appended claims.

[0040] It is to be understood that the term "vehicle" or "vehicular" or other synonymous terms as used herein include motor vehicles in general such as passenger cars including sports utility vehicles (SUVs), buses, trucks, various utility vehicles, watercraft including a variety of boats and ships, aircraft, and the like, and includes hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles, hydrogen-powered vehicles, and other alternative fuel vehicles (e.g., fuel derived from sources other than petroleum). As referred to herein, a hybrid vehicle represents a vehicle that has two or more sources of power, such as both gasoline-powered and electric-powered vehicles.

[0041] The above and other features of the invention are explained below.

[0042] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0043] The present invention relates to a battery pack housing assembly for a vehicle, particularly an electric or hybrid vehicle, in which a lightweight plastic composite material is used as a housing material. More particularly, it relates to a housing body in which battery packs are arranged among the various other components of a battery pack housing assembly, i.e., a lower housing requiring high load-bearing and rigidity characteristics.

[0044] In the present invention, a housing can be manufactured by an extrusion molding method using a fiber-reinforced plastic composite to reduce weight. Specifically, a long fiber with an aspect ratio (i.e., length by diameter (L / D)) of approximately 1000 or more or a continuous fiber (i.e., a fiber without a break therein) can be used to improve the structural rigidity, collision characteristics, and dimensional stability of the housing.

[0045] In the present invention, when manufacturing a large plastic composite housing that can accommodate multiple battery packs, a continuous fiber can be used locally at a portion where relatively high rigidity is required. The use of the continuous fiber can allow one or more various parts, such as typical structural reinforcement cross members, side members, and brackets, to be omitted at the same time, thereby reducing weight and cost.

[0046] Hereinafter, an embodiment in which a continuous fiber (or long fiber with an aspect ratio of approximately 1000 or more) is used in the lower case (i.e., the case body requiring high load-bearing and high rigidity characteristics) will be described with reference to the accompanying drawings. However, the continuous fiber (or long fiber with an aspect ratio of approximately 1000 or more) can also be used in an upper cover (i.e., an upper cover arranged and coupled to cover the lower case).

[0047] Fig. 2 is a view illustrating the structure of a battery for an electric vehicle in which a plurality of battery packs are housed by a battery pack housing assembly according to an embodiment of the present invention. The battery pack housing assembly may include a lower housing (also referred to as a housing body) 200 for housing a battery pack 300 and a cover (also referred to as an upper cover) 100 coupled to the lower housing 200.

[0048] Fig. 3 to 5 are views illustrating a battery pack housing assembly according to an embodiment of the present invention, in which Fig. 3 shows a perspective view illustrating a top side of a lower housing 200, Fig. 4 shows a perspective view illustrating a bottom side of the lower housing 200, and Fig. 5 shows a cross-sectional view taken along the line AA of Fig. 3 is taken.

[0049] With reference to Fig. 3, the lower housing 200 can be manufactured using long fiber reinforced thermoplastics (LFRT), in which a long fiber is reinforced in a plastic matrix.

[0050] In this case, the plastic matrix of the fiber-reinforced composite may comprise one or more thermoplastic resin materials, including, but not limited to, polypropylene (PP), polyamide (PA), polyetheretherketone (PEEK), polycarbonate (PC), polyphenylenesulfone (PPS), polyphenylene ether (PPE), and thermoplastic polyurethane (TPU).

[0051] The long fiber used as a reinforcing fiber can be selected from glass fibers, carbon fibers, aramid fibers, volcanic ash fibers, natural fibers and combinations thereof.

[0052] When the lower casing 200 is compression molded using the fiber-reinforced thermoplastic composite material containing the reinforcing fiber, the lower casing 200 may be formed such that the length of remaining or residual reinforcing fibers is sized to provide the fiber having an aspect ratio of about 1000 or more.

[0053] In particular, if the aspect ratio of the remaining or residual reinforcing fiber is less than about 1000, a sufficient stiffness reinforcement effect cannot be achieved. According to preferred embodiments, the aspect ratio of the remaining reinforcing fiber may range from about 1000 to about 10,000.

[0054] In general, the dimensional accuracy of parts can be directly influenced by the shape of the parts, but can be improved by the proper selection of materials and forming processes. Thus, according to various embodiments, the fiber-reinforced plastic composite housing can be manufactured by an extrusion-compression molding process, which can minimize residual stresses caused by shear force during compression molding of the product.

[0055] According to various embodiments, when manufacturing the lower housing 200, the long fiber may comprise approximately 30 wt.% to approximately 70 wt.% of the total weight of the plastic composite used in forming the lower housing. If the weight of the long fiber is less than approximately 30 wt.%, the desired mechanical properties may not be achieved. On the other hand, if the weight of the long fiber is greater than approximately 70 wt.%, the flowability during molding may be reduced, causing a reduction in moldability and deterioration in external quality.

[0056] When manufacturing the fiber-reinforced plastic composite lower casing 200, the long fiber and the continuous fiber may be blended and used as a reinforcing fiber. Specifically, a continuous fiber-type reinforcing fiber may be blended with the long fiber. The continuous fiber may be applied to the entire area of ​​the lower casing 200 (i.e., throughout the entire lower casing 200), and in some preferred embodiments, the continuous fiber may be used locally only in one or more portions where high rigidity is desired.

[0057] For example, the continuous fiber may be used only partially in portions of the lower housing 200 where typical reinforcement members such as cross members, side members, and brackets are located, or in portions of the lower housing 200 that are coupled to the vehicle body by bolting and the like. When the continuous fiber is used locally, typical structural reinforcement members may be formed integrally with the housing installation location of the continuous fiber. Accordingly, these separate parts (e.g., cross members, side members, brackets, etc.) may be omitted.

[0058] In the prior art, a lower housing can be manufactured using a fiber-reinforced plastic composite, and a double-overlapped plate structure with a closed-section structural portion can be formed instead of a simple planar shape to absorb collision energy. Thus, component rigidity and component collision characteristics can be achieved.

[0059] On the other hand, in the present invention, the lower casing 200 can be manufactured in a single-layer structure instead of a double-overlapped plate, and the long fiber and the continuous fiber with excellent mechanical properties and excellent dimensional stability can be used entirely or locally together. Thus, structural reinforcement elements (i.e., peripheral parts such as cross members, side members, brackets) can be omitted to achieve weight reduction, simplification of the manufacturing process, improvement in productivity (mass production), and cost savings.

[0060] Separate from the lower housing 200, a separate reinforced member (hereinafter referred to as a continuous fiber reinforced member) 212 may be formed from a plastic composite material in which a continuous fiber is used as a reinforcing fiber in a plastic matrix. The continuous fiber reinforced member 212 may be locally coupled to portions of the lower housing 200 where stresses are concentrated during molding of the lower housing 200.

[0061] In addition to the continuous fiber used as the reinforcing fiber of the lower housing 200, the continuous fiber reinforced member 212 may be additionally used. The advantages of using the continuous fiber in the reinforced member 212 may be similar to those of using the continuous fibers in the lower housing 200, as described above.

[0062] The continuous fibers used in the lower housing 200 and the separate continuous fiber reinforced member 212 may be selected from glass fibers, carbon fibers, aramid fibers, volcanic ash fibers, natural fibers, and combinations thereof.

[0063] The plastic matrix of the continuous fiber reinforced member 212 may comprise at least one thermoplastic resin material such as polypropylene (PP), polyamide (PA), polyetheretherketone (PEEK), polycarbonate (PC), polyphenylenesulfone (PPS), polyphenylene ether (PPE), and thermoplastic polyurethane (TPU), and combinations thereof.

[0064] The plastic matrices of the lower housing 200 and the continuous fiber-reinforced member 212 may be identical or different. Using an identical plastic matrix can further improve the interfacial bond strength between different types of parts.

[0065] As in Fig. 3 to 5, the continuous fiber reinforced member 212 can be used in side support parts 211 projecting from both the right and left sides of the lower case 200, respectively. Fig. 6 is a perspective view showing a continuous fiber reinforced member 212 used on a side support part 211 of the lower case. Fig. 7 shows a cross-sectional view illustrating a continuous fiber reinforced member 212 coupled to a side support part 211 of the lower housing 200.

[0066] With reference to Fig. 3 to 5 and 7, the side support members 211 may protrude from both the right and left sides of the lower housing (housing body) 200 for bolt coupling (or other suitable coupling) to the vehicle body. The continuous fiber reinforced member 212 may be coupled to the bottom surface / underside of the side support member 211.

[0067] Thus, the continuous fiber reinforced member 212 and the side support parts 211 integrally formed on both sides of the lower case 200 can form a side support for coupling with the vehicle body.

[0068] As in Fig. 5 and Fig. 7, the continuous fiber reinforced member 212 forming the side support may have a bracket shape that can form a closed-section structural portion when the continuous fiber reinforced member 212 is coupled to the side support part 211 of the lower case 200.

[0069] With reference to Fig. 6, a plurality of reinforcing ribs 213 may be arranged on the bottom surface of the continuous fiber reinforced member 212. The plurality of reinforcing ribs 213 may be arranged at a predetermined pitch, for example, a uniform or uneven pitch.

[0070] The continuous fiber reinforced member 212 may be joined to the lower housing 200 by any suitable means, such as an adhesive or one of vibration welding, ultrasonic welding, infrared (ID) welding, hot plate welding, laser welding, and thermal welding.

[0071] According to embodiments of the present invention, instead of the continuous fiber, a long fiber may be used as a reinforcing fiber for the reinforced member 212 constituting the side support of the lower case 200. In this case, the aspect ratio of remaining long fibers may be equal to or greater than approximately 1000 during press-forming of the reinforced member 212 to achieve a sufficient rigidity-enhancing effect.

[0072] In particular, the long-fiber reinforced member 212 may have a bow shape and may be reinforced with a long fiber having an aspect ratio of about 1000 or more. According to various embodiments, the aspect ratio of the long fiber may range from about 1000 to about 10,000 during compression molding.

[0073] The long fiber may account for approximately 30 wt.% to approximately 70 wt.% of the total weight of the plastic composite used as a material for molding the long fiber reinforced member 212. If the weight of the long fiber is less than approximately 30 wt.%, the desired mechanical properties may not be achieved. On the other hand, if the weight of the long fiber is greater than approximately 70 wt.%, the flowability during molding may be reduced, causing a reduction in moldability and deterioration in external quality.

[0074] According to further embodiments, the long fiber and the continuous fiber may be blended and the blend may be used as a reinforcing fiber for the reinforced member 212.

[0075] In order to increase the structural rigidity and collision energy absorption performance of the lower casing 200, a sheet type (ie, planar structure) of continuous fiber reinforced members 220a and 220b may be locally arranged on the bottom surface of the lower casing (casing body) 200.

[0076] In particular, a plurality of continuous fiber-reinforced members 220a and 220b may be integrally formed during molding of the lower housing 200. Also, the continuous fiber-reinforced members 220a and 220b may be cut into appropriate sizes as desired and then arranged on the underside of the lower housing 200, each in a single layer or in multiple layers.

[0077] The continuous fiber reinforced elements 220a and 220b may be embedded in the bottom of the lower housing 200 or may be attached to the surface of the bottom of the lower housing 200.

[0078] In particular, the continuous fiber reinforced elements 220a and 220b can be arranged on the top (inner side), the bottom surface, or both the top and bottom surfaces of the lower housing 200 in a particular arrangement and within a particular area as desired.

[0079] Fig. 8 is a view illustrating a plurality of sheet-like continuous fiber reinforced members 220a arranged on the bottom of a lower case 200 according to another embodiment of the present invention.

[0080] Fig. 9 is a view showing a sheet-like continuous fiber reinforced member 220b having a large area disposed on the bottom surface of a lower case 200 according to another embodiment of the present invention.

[0081] Thus, in the present invention, since the sheet-like continuous fiber reinforced members 220a and 220b can be locally mounted in the lower case 220, the structural rigidity and collision energy absorption performance of the lower case 200 can be improved.

[0082] To attach the continuous fiber-reinforced members 220a and 220b, the continuous fiber-reinforced members 220a and 220b may be cut into appropriate sizes and then stacked into a single layer or multiple layers and preheated. Thereafter, the continuous fiber-reinforced members 220a and 220b may be arranged or attached to desired locations within a mold of the lower casing 200, and then the lower casing may be formed by an extrusion molding apparatus or the like.

[0083] When a fiber-reinforced high-temperature composite material supplied as a material of the lower casing 200 is placed in the mold for extrusion molding, the lower casing 200 can be formed integrally with the continuous fiber-reinforced members 220a and 220b without a separate subsequent process.

[0084] Fig. 10 is a view illustrating a sheet-like continuous fiber-reinforced member 220c coupled to both side support portions 211 of a lower housing according to another embodiment of the present invention. As shown, the continuous fiber-reinforced member is disposed at two locations. Of course, any number of locations could be used as appropriate, and thus the invention is not limited to only the illustrated number and positions of the continuous fiber-reinforced members 220c.

[0085] In this embodiment, a sheet-like continuous fiber-reinforced member 220c may be arranged instead of the above-described bow-type continuous fiber-reinforced member 212. The continuous fiber-reinforced member 212 may be formed from the same materials as the bow-type continuous fiber-reinforced member 212.

[0086] Fig. 11 is a view illustrating sheet-like continuous fiber-reinforced members 220a and 220c coupled in plurality to both side support portions 211 and the bottom surface of the lower case 200 according to another embodiment of the present invention. Specifically, according to this embodiment, the continuous fiber-reinforced members 220a and 220c are arranged at five locations. Of course, any number of locations could be suitably used, and thus the invention is not limited to only the illustrated number and positions of the continuous fiber-reinforced members 220a and 220c.

[0087] Here, the continuous fiber reinforced member 220a can be formed on the underside of the lower case 200 by a method and structure similar to those of Fig. 8 and Fig. 9 (the continuous fiber reinforced element can also be arranged on the lower surface of the lower housing 200).

[0088] According to various embodiments, the reinforced elements 220a, 220b, and 220c, which are separately manufactured and arranged on the lower housing 200, may comprise a long fiber having an aspect ratio of approximately 1000 or more as a reinforcing fiber instead of the continuous fiber.

[0089] The long fiber reinforced members 220a, 220b, and 220c reinforced with the long fiber having an aspect ratio of about 1000 or more may be arranged, and in this case, the long fiber may account for about 30 wt% to about 70 wt% of the total weight of the plastic composite constituting the long fiber reinforced members 220a, 220b, and 220c.

[0090] If the weight of the long fiber is less than about 30 wt%, the desired mechanical properties cannot be achieved, and if the weight of the long fiber is greater than 70 wt%, the fluidity may be reduced during molding, causing a reduction in moldability and deterioration in external quality.

[0091] According to various embodiments, the long fiber and the continuous fiber may be blended and the blend may be used as a reinforcing fiber for the long fiber reinforced members 220a, 220b and 220c, which are manufactured separately.

[0092] When the bow-like continuous fiber reinforced element 212 forming the side support of the lower housing 200 ( Fig. 3 to 7), and the continuous fiber reinforced elements 220a, 220b and 220c, which are arranged separately in the lower housing 200 ( Fig. 8 to 11), the continuous fiber may account for approximately 30 wt.% to approximately 70 wt.% of the total weight of the plastic composite forming the reinforcing members. If the weight of the continuous fiber is less than approximately 30 wt.%, the desired mechanical properties may not be achieved, and if the weight of the continuous fiber is greater than approximately 70 wt.%, the flowability during molding may be reduced, causing a reduction in moldability and deterioration in external quality.

[0093] As described above, in the present invention, the lower casing 200 is reinforced with the thermoplastic composite material using a reinforcing fiber, particularly a continuous fiber type reinforcing fiber. The continuous fiber used in the present invention can be significantly different from the long fiber with respect to a specific length because the continuous fiber has a fiber structure without breakage in one or intersecting directions. Thus, the present invention can provide an additional advantage according to the use of the continuous fiber.

[0094] When the continuous fiber is used in a plastic matrix to form the lower case and a plastic matrix of a continuous fiber reinforced member is further provided, a unidirectional tape or fabric woven with a continuous fiber may be used.

[0095] Here, the unidirectional belt may have an arrangement in which many strands of long fibers extend longitudinally in the same direction (strand arrangement), and the continuous fiber fabric may have a woven structure in which the continuous fibers cross each other in the longitudinal and transverse directions.

[0096] In short, the continuous fiber can be of a unidirectional (DU) or woven type. Some examples of the woven type may include solid, plain, and satin types woven at 0° / 90°, and a type woven at 0° / 90° / -45° / 45°.

[0097] In the present invention, the lower casing and the continuous fiber-reinforced member can be manufactured using the unidirectional belt or the continuous fiber woven fabric described above. Accordingly, the lower casing and the continuous fiber-reinforced member can be manufactured such that the continuous fiber can be arranged in one direction in the plastic matrix or fixed in a woven fiber form.

[0098] In the embodiments of Fig. 8, Fig. 9 and Fig. 11, when the continuous fiber reinforced member in which the continuous fiber is arranged in one direction is used (for example, the unidirectional tape is used as a fiber reinforced material), the continuous fibers in the continuous fiber reinforced member may be arranged in a "crossing direction" with respect to the front and rear longitudinal direction of the lower case (that is, the continuous fibers in the continuous fiber reinforced member may be arranged in the right and left width directions with respect to the front and rear longitudinal direction of the lower case).

[0099] Reference numerals 215a and 215b denote reinforcing ribs arranged on the underside of the lower housing 200. According to various embodiments, a plurality of reinforcing ribs may be partially or entirely arranged to improve the rigidity of the lower housing 200.

[0100] The reinforcing ribs 215a and 215b may be formed on the bottom surface to occupy a large area of ​​the lower case 200, and these reinforcing ribs 215a and 215b may be formed in various shapes including, but not limited to, an L-shape, lattice, net, cross, and honeycomb shape.

[0101] For example, as in Fig. 4, a lattice-like reinforcing rib 215a may be arranged on the lower surface of the lower case 200, and the separate reinforcing rib 215b may be additionally arranged on the inside of the lattice-like reinforcing rib 215a to diagonally cross the lattice-like reinforcing rib 215a.

[0102] The reinforcing ribs 215a and 215b may further comprise a combination of structures of different shapes as described above.

[0103] Thus, when the fiber-reinforced plastic composite is used in the present invention, the continuous fiber can be used in the side brackets or portions where high rigidity is required, thereby providing capacity for mass production and effectively overcoming limitations of dimensional deviation and deformation after molding. Also, the present invention is capable of improving both the rigidity and collision characteristics of parts.

[0104] Furthermore, since the housing is locally reinforced with the continuous fibers in addition to the plastic composite material, the weight can be significantly reduced compared to the use of typical steel parts and reinforcement elements. Furthermore, various parts such as cross members and side members can be eliminated. Consequently, the present invention can greatly contribute to reducing the overall weight of the lower housing and assembly, as well as reducing manufacturing costs.

[0105] The present invention will now be described in more detail by the following examples. However, it will be understood by those skilled in the art that these examples are provided merely to illustrate the present invention and are not intended to limit the scope of the present invention. EXAMPLES

[0106] The following examples illustrate the invention and are not intended to limit it. Example 1:

[0107] The lower housing 200 and the bow-like reinforced member 212 were manufactured by an extrusion-compression molding process using a PA6 composite material (Material-A) reinforced with approximately 30 wt% carbon fiber with an average aspect ratio of approximately 1000 (see Fig. 3 to 7).

[0108] Here, the tensile strength and tensile modulus of the PA6 composite in the longitudinal direction of the fiber were approximately 250 MPa and approximately 20 GPa, respectively. The connection between the lower housing 200 and the stirrup-like reinforced member 212 was performed by a vibration welding process. During vibration welding, a weld bead structure was added to an overlapping area of ​​approximately 1.5 mm (see Fig. 7).

[0109] The top cover 100 was manufactured by the same process using the PA6 plastic composite material (Material-A), and the housing assembly was completed using the lower housing to which the reinforced members 212 are connected and the top cover 100.

[0110] A typical housing assembly using steel parts was manufactured by welding more than 30 parts, and the total weight of the housing assembly was 35 kg. However, in the housing assembly according to the example, the weight of the housing assembly was reduced to approximately 11 kg by using four parts of the lower housing 200 including the plastic composite material, the bracket-like reinforced member 212 on the right and left sides, and the upper cover 100.

[0111] The vibration endurance test and sled collision test were also conducted using the current 300 battery pack, and it was confirmed that certain requirements were met. After molding, the concentration rate of the bottom case was approximately 1.5 / 1000 (0.15%). Example 2:

[0112] A sheet-like continuous fiber-reinforced member 220a was manufactured using a plastic composite material (Material-B) in which approximately 57 wt% of carbon fiber of a continuous fiber and woven fiber types were used, and PA66 was used as a matrix. After preheating, the continuous fiber-reinforced member 220a was mounted in the mold of the lower case, and then the Material-A of the first example obtained from the extrusion apparatus was overmolded to produce the final lower case 200 assembled with the continuous fiber-reinforced member 220a.

[0113] In this case, a bracket-like reinforced member 212 was attached to the side support part 211 of the lower case 200, similar to that of the first example.

[0114] The tensile strength and tensile modulus of material-B in the longitudinal direction of the fiber were approximately 785 MPa and 53 GPa, respectively. Due to the addition of a reinforced carbon fiber fabric element, the weight reduction effect was equivalent to that of the first example, but the concentration rate after molding was reduced to approximately 1 / 1000 (0.1%), indicating that the dimensional stability was improved.

[0115] Thus, according to a battery pack case assembly for an electric vehicle and a method of manufacturing the battery pack case assembly according to an embodiment of the present invention, since a lightweight plastic composite material is used as a case material and a continuous fiber is used locally at a portion where stresses are concentrated, it is possible to reduce the weight while improving the structural rigidity, collision characteristics, and dimensional stability.

[0116] In particular, since a long fiber and a continuous fiber with excellent mechanical properties and dimensional stability are used, typical structural reinforcement elements (i.e., peripheral parts such as cross members, side members, and brackets) can be omitted. Consequently, various advantages such as weight reduction, simplification of the manufacturing process, improved productivity (mass producibility), and cost savings can be achieved.

Claims

[1] A battery pack housing assembly for an electric vehicle, comprising: a housing body (200) for accommodating a battery pack (300); and a cover (100) detachably coupled to the housing body (200), wherein the housing body (200) is formed from a plastic composite material in which a long fiber or a mixture of a long fiber and a continuous fiber is used as a reinforcing fiber in a plastic matrix, a first separate reinforced element (212) connected to one or more side support parts (211) of the housing body (200), wherein the first separate reinforced element (212) is formed from a plastic composite material in which a long fiber, a continuous fiber or a mixture of a long fiber and a continuous fiber is used as the reinforcing fiber in a plastic matrix, and a second separate reinforced element (220a, 220b) having a planar shape, which is arranged on an underside of the housing body (200), wherein the second separate reinforced element (220a, 220b) is formed from a plastic composite material comprising a continuous fiber as a reinforcing fiber in a plastic matrix, wherein the housing body (200) is formed integrally with the second separate reinforced member (220a, 220b) by an extrusion press molding device and the bottom of the housing body (200) is formed in a single-layer structure. [2] The battery pack housing assembly of claim 1, wherein the long fiber of the housing body (200) and the long fiber of the first separate reinforced member (212) both have an aspect ratio of approximately 1000. [3] The battery pack housing assembly of claim 1, wherein the long fiber of the housing body (200) and the long fiber of the first separate reinforced member (212) both have an aspect ratio of about 1000 to about 10000. [4] The battery pack housing assembly of claim 1, wherein the plastic matrix of the first separate reinforced member (212) is selected from the group consisting of: polypropylene (PP), polyamide (PA), polyetheretherketone (PEEK), polycarbonate (PC), polyphenylenesulfone (PPS), polyphenylene ether (PPE), thermoplastic polyurethane (TPU), and combinations thereof. [5] The battery pack housing assembly of claim 1, wherein the plastic matrix of the housing body (200) is selected from the group consisting of polypropylene (PP), polyamide (PA), polyetheretherketone (PEEK), polycarbonate (PC), polyphenylenesulfone (PPS), polyphenylene ether (PPE), thermoplastic polyurethane (TPU), and combinations thereof. [6] The battery pack housing assembly of claim 1, wherein the long fiber or continuous fiber of the housing body (200) and the long fiber or continuous fiber of the first separate reinforced member (212) are selected from the group consisting of: glass fibers, carbon fibers, aramid fibers, volcanic ash fibers, natural fibers, and combinations thereof. [7] The battery pack casing assembly according to claim 1, wherein the first separate reinforced member (212) has a bow-like shape with one or more reinforcing ribs (213), and wherein, when the side bracket (211) of the casing body (200) and the first separate reinforced member (212) are coupled together, a structural portion having a closed cross-section for absorbing collision energy is formed. [8] The battery pack housing assembly of claim 1, wherein the first separate reinforced member (212) has a planar shape and is coupled to the opposite side supports (211) of the housing body (200). [9] The battery pack housing assembly according to claim 1, wherein the second separate reinforced member (220a, 220b) is disposed on the underside of the housing body (200) and is connected to a surface of the underside of the housing body (200) or is disposed within the underside of the housing body (200). [10] The battery pack housing assembly of claim 1, wherein the second separate reinforced member (220a, 220b) is connected to a surface of the bottom surface of the housing body (200), the surface being an upper surface, a lower surface, or both a lower and an upper surface of the bottom surface. [11] The battery pack casing assembly according to claim 1, wherein the continuous fiber of the second separate reinforced member (220a, 220b) disposed on the underside of the casing body (200) is arranged in one direction in the plastic matrix, or is fixed in a form of woven fiber in which the continuous fibers cross each other in longitudinal and transverse directions. [12] The battery pack case assembly according to claim 11, wherein the continuous fiber is arranged lengthwise in a direction in a right and left width direction orthogonal to a front and rear longitudinal direction of the case body (200). [13] The battery pack housing assembly of claim 9, wherein the plastic matrix of the second separate reinforced member (220a, 220b) disposed on the underside of the housing body (200) is selected from the group consisting of: polypropylene (PP), polyamide (PA), polyetheretherketone (PEEK), polycarbonate (PC), polyphenylenesulfone (PPS), polyphenylene ether (PPE), thermoplastic polyurethane (TPU), and combinations thereof. [14] The battery pack housing assembly of claim 1, wherein the continuous fiber of the second separate reinforced member (220a, 220b) disposed on the underside of the housing body (200) is selected from the group consisting of: glass fibers, carbon fibers, aramid fibers, volcanic ash fibers, natural fibers, and combinations thereof. [15] A method of manufacturing a battery pack housing assembly for an electric or hybrid vehicle, comprising a housing body (200) for receiving a battery pack (300), and a cover (100) removably coupled to the housing body (200), the method comprising: Forming the housing body (200) using a plastic composite material in which a long fiber or a mixture of a long fiber and a continuous fiber is used as a reinforcing fiber in a plastic matrix; Forming a first separate reinforced element (212) using a plastic composite material in which a long fiber, a continuous fiber or a mixture of a long fiber and a continuous fiber is used as the reinforcing fiber in a plastic matrix, wherein the first separate reinforced element (212) is connected to one or more side supports (211) of the housing body (200); Forming a second separate reinforced element (220a, 220b) having a planar shape, which is arranged on an underside of the housing body (200), wherein the second separate reinforced element (220a, 220b) is formed from a plastic composite comprising a continuous fiber as a reinforcing fiber in a plastic matrix; and Connecting the first separate reinforced element (212) to both brackets (211) of the housing body (200) for coupling to a vehicle body, wherein the housing body (200) is formed integrally with the second separate reinforced member (220a, 220b) by an extrusion press molding device and the bottom of the housing body (200) is formed in a single-layer structure. [16] The method of claim 15, wherein in the step of forming the housing body (200) and the first separate reinforced member (212), an aspect ratio of a remaining long fiber in the housing body (200) and in the reinforced member is equal to or greater than about 1000. [17] The method of claim 15, wherein the plastic matrix of the first separate reinforced element (212) is selected from the group consisting of: polypropylene (PP), polyamide (PA), polyetheretherketone (PEEK), polycarbonate (PC), polyphenylenesulfone (PPS), polyphenylene ether (PPE), thermoplastic polyurethane (TPU), and combinations thereof. [18] The method of claim 15, wherein the long fiber or continuous fiber of the housing body (200) and the long fiber or continuous fiber of the first separate reinforced element (212) are selected from the group consisting of: glass fibers, carbon fibers, aramid fibers, volcanic ash fibers, natural fibers, and combinations thereof. [19] The method of claim 15, wherein the step of forming the first separate reinforced member (212) comprises forming the reinforced member (212) in a bow-like shape with one or more reinforcing ribs (213), wherein, when the side support part (211) of the housing body (200) and the first separate reinforced element (212) having the bracket-like shape are connected to each other, a structural region with a closed cross section for absorbing collision energy is formed. [20] The method of claim 15, wherein the step of forming the first separate reinforced member (212) comprises forming the reinforced member (212) in a sheet-like shape for coupling to both side support parts (211) of the housing body (200). [21] The method of claim 15, further comprising: Forming a second separate reinforced element (220a, 220b) having a sheet-like shape using a plastic composite material comprising a continuous fiber as a reinforcing fiber in a plastic matrix; and Attaching the second separate reinforced element (220a, 220b) having a planar shape to the underside of the housing body (200). [22] The method according to claim 21, wherein in the step of forming the second separate reinforced member (220a, 220b) having a sheet-like shape, a unidirectional tape or a woven fiber woven with the continuous fiber is used. [23] The method according to claim 22, wherein a unidirectional ribbon is used and the continuous fiber is arranged lengthwise in a right and left width direction orthogonal to a forward and backward longitudinal direction of the case body (200). [24] The method of claim 15, wherein the plastic matrix of the second separate reinforced element (220a, 220b) attached to the underside of the housing body (200) is selected from the group consisting of: polypropylene (PP), polyamide (PA), polyetheretherketone (PEEK), polycarbonate (PC), polyphenylenesulfone (PPS), polyphenylene ether (PPE), thermoplastic polyurethane (TPU), and combinations thereof. [25] The method of claim 15, wherein the continuous fiber of the second separate reinforced member (220a, 220b) attached to the bottom of the housing body (200) is selected from the group consisting of: glass fibers, carbon fibers, aramid fibers, volcanic ash fibers, natural fibers, and combinations thereof.

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