Steel plate tailored blank press-formed battery tray

Abstract

A device for housing a portion of a vehicle battery assembly includes a tray. The tray is configured to receive the portion of the vehicle battery assembly. The tray defines a floor, a front wall, a rear wall, and a pair of side walls extending from the front wall to the rear wall. The tray includes a first steel member and a second steel member. The first steel member is joined with the second steel member to form a single continuous part. The first steel member defines most of the floor. The second steel member is positioned at two or more corners of the tray.

Description

Background Art

[0001] This application claims priority to the disclosure of U.S. Provisional Application No. 63 / 468,332, filed May 23, 2023, entitled “Steel Tailored Blank Press Formed Battery Tray,” the disclosure of which is incorporated herein by reference in its entirety.

[0002] Some vehicles may be equipped with a specific vehicle battery system. For example, in a fully electric vehicle powered entirely by electricity, a vehicle battery system is provided to supply all the electrical power required to drive the propulsion force and the attached electrical system. Similarly, in certain hybrid vehicles driven by a combination of electricity and an internal combustion engine, a vehicle battery system may be provided to supply at least a portion of the electrical power required to drive the propulsion force and the attached electrical system.

[0003] In such vehicles, the vehicle battery system may be sensitive to damage caused by various environmental factors encountered during driving in various climates and terrains. Such environmental factors include the possibility of collisions with other vehicles, objects near the road, debris on the road, etc. encountered during driving. Other environmental factors include natural conditions such as humidity, rain, ice, snow, hail, etc. Therefore, in order to avoid damage to the sensitive vehicle battery system, the battery system can be arranged and / or housed within various battery storage structures to protect the system components from environmental factors.

[0004] Examples of battery storage structures are described in the following patents or published documents: U.S. Patent No. 10,886,513, “Vehicle Battery Tray with Tabbed Container Base Integration,” issued January 5, 2012; U.S. Patent No. 10,483,510, “Polarized Battery Tray for Vehicles” (issued November 19, 2019); and International Publication No. WO2022 / 197830, “Vehicle Battery Tray and Method of Manufacturing the Same” (published September 22, 2022). The disclosures of these are incorporated herein by reference in their entireties.

[0005] Although various battery storage structures have been manufactured and used, it is believed that no one manufactured or used the invention described herein prior to the inventor. [Brief explanation of the drawing]

[0006] The present invention can be better understood by referring to the following description of the embodiments and the accompanying drawings. In the drawings, the same reference numerals indicate the same components. [Figure 1] Figure 1 is a perspective view showing an example of a vehicle chassis including a battery storage structure. [Figure 2] Figure 2 shows an exploded perspective view of the battery storage structure shown in Figure 1. [Figure 3] Figure 3 shows a perspective view of the battery tray of the battery storage structure shown in Figure 1. [Figure 4] Figure 4 shows a plan view of the battery tray shown in Figure 3. [Figure 5] Figure 5 is a perspective view showing an example of an alternative battery tray that can be easily incorporated into the battery storage structure of Figure 1. [Figure 6] Figure 6 shows a plan view of the battery tray shown in Figure 5. [Figure 7] Figure 7 shows a plan view of the blank used to form the battery tray shown in Figure 5. [Figure 8] Figure 8 shows a plan view of another blank used to form the battery tray of Figure 5. [Figure 9] Figure 9 shows a perspective view of another exemplary battery tray used in the battery storage structure of Figure 1. [Figure 10] Figure 10 shows the detailed top surface heat distribution diagram of the battery tray after the digital model of Figure 9 has been stamped using computer simulation. [Figure 11] Figure 11 shows a perspective heatmap of the digital model of the battery tray from Figure 9 after it has been subjected to a ballistic impact simulated by a computer. [Figure 12] Figure 12 is a plot showing the relationship between force and displacement in a ballistic impact, as determined by the computer simulation in Figure 11. [Figure 13] Figure 13 shows a perspective view of another exemplary battery tray used in the battery storage structure of Figure 1. [Figure 14] Figure 14 shows the heat distribution diagram of the upper details after the digital model of the battery tray from Figure 13 has been subjected to a computer simulation of a press working operation. [Figure 15] Figure 15 shows a perspective heatmap of the digital model of the battery tray from Figure 13 after it has been subjected to a ballistic impact simulated by a computer. [Figure 16] Figure 16 is a plot showing the relationship between force and displacement in a ballistic impact, based on the computer simulation in Figure 13.

[0007] The drawings are not intended to be limiting in any sense, and it is assumed that various embodiments of the invention may be carried out in various other ways, including those not necessarily shown in the drawings. The accompanying drawings are incorporated into and form part of the specification, illustrating some aspects of the invention and, in conjunction with the description, illustrating the principles of the invention. However, it should be understood that the invention is not limited to the exact configurations shown. [Modes for carrying out the invention]

[0008] The following description relating to specific embodiments of the present invention should not be used to limit the scope of the invention. Other examples, features, aspects, embodiments, and advantages will be apparent to those skilled in the art from the following description. This description illustrates one of the best embodiments devised for carrying out the invention. As should be understood, the invention may have other different apparent aspects, none of which shall depart from the scope of the invention. Accordingly, the drawings and description should be considered illustrative and not limiting.

[0009] Figure 1 shows an example of a vehicle chassis (10) commonly configured for use as a chassis for an electric vehicle or a hybrid vehicle. The vehicle chassis (10) supports a number of wheels (12) and includes one or more rails (14) and one or more cross members (16). The rails (14) and cross members (16) are typically connected to each other to support the wheels (12) and other vehicle-related structures (not shown) and to provide structural rigidity to the vehicle chassis (10). Thus, the rails (14) and cross members (16) include various rigid structural components, such as tubular alloy structures, to provide such structural rigidity to the vehicle chassis (10).

[0010] The combination of the rail (14) and the cross member (16) further defines the battery housing area (18). As will be described later, the battery housing area (18) is typically configured to receive a battery storage structure (100) that houses one or more components of the vehicle battery assembly (200), such as one or more battery cells (210). It is sometimes desirable for the vehicle chassis (10) to define the battery receiving area (18). This is because integrating the vehicle battery assembly (200) into the chassis (10) can lower the center of gravity and protect the components of the vehicle battery assembly (200), such as the battery cells (210). Note that in other examples, the battery housing area (18) can be omitted, and the battery storage structure (100) can be located or integrated into other structures of the vehicle. Therefore, the battery housing area (18) is optional and may be omitted in some embodiments.

[0011] As will be described later, a vehicle battery assembly (200) can be configured in a variety of ways. Suitable configurations include a variety of shapes and sizes. Such configurations may depend on a variety of factors, such as the specific power configuration used (e.g., all-electric vs. hybrid) and other electrical requirements of the vehicle. As an example, a vehicle battery assembly (200) includes a variety of combinations of one or more battery cells (210), suitable electronics and / or other related components (not shown). The battery cells (210) can include a variety of configurations. Examples of suitable configurations for battery cells (210) include lithium ions, lithium polymers, lithium metals, lead acids, nickel cadmium, nickel metal hydrides, and / or other suitable configurations that can be understood by those skilled in the art in light of the teachings herein.

[0012] While this specification describes the use of the battery housing structure (100) in the specific context of a vehicle battery assembly (200), it should be understood that the battery housing structure (100) can be used in combination with various alternative vehicle battery assemblies. These alternative vehicle battery assemblies may include different battery cell configurations, battery wiring configurations, electronic configurations, battery cell locations, battery cell sizes, battery cell shapes, and / or other variations.

[0013] Figures 2 and 3 show the battery housing structure (100) in more detail. The battery housing structure (100) is generally configured to house and structurally protect one or more components of the vehicle battery assembly (200), as will be described later. The battery housing structure (100) includes a battery cover (110) and a battery tray (120). The battery cover (110) and the battery tray (120) are configured to connect to each other in order to house one or more components of the vehicle battery assembly (200) (e.g., battery cells (210)) between the battery cover (110) and the battery tray (120). In some examples, as described above, the combination of the battery cover (110) and the battery tray (120) may be housed within a battery housing area (18) of the vehicle chassis (10).

[0014] The battery cover (110) defines a shape substantially corresponding to the shape of the battery tray (120) and is typically configured to fit with the battery tray (120). As will be described later, the battery tray (120) in this embodiment is typically rectangular. Therefore, the battery cover (110) in this embodiment is similarly rectangular. Furthermore, the battery cover (110) has at least some depth or hollow internal space for housing a portion of the vehicle battery assembly (200). The battery cover (110) in this embodiment includes a single piece of mild steel. In other embodiments, the battery cover (110) may include one or more of the features described later with respect to the battery tray (120). For example, the battery cover (110) may be configured to form a single piece by welding different materials together. Optionally, the battery cover (110) may include one or more geometric features configured to provide structural rigidity to the battery cover (110). In other examples, the battery cover (110) may be formed from a single piece of steel, such as mild steel. In yet another example, the battery cover (110) is entirely optional and may be completely omitted.

[0015] The battery tray (120) is positioned beneath a portion of the vehicle battery assembly (200) and the battery cover (110). The battery tray (120) is typically configured to receive and house a portion of the vehicle battery assembly (200), such as battery cells (210). The battery tray (120) is also typically configured to provide at least some degree of protection to the portion of the vehicle battery assembly (200). For example, the battery tray (120) is configured to provide rigidity and hardness to protect the portion of the vehicle battery assembly (200) from frontal and lateral impacts. The battery tray (120) is also configured to protect the portion of the vehicle battery assembly (200) from ballistic impacts. In addition, the battery tray (120) is configured to protect the portion of the vehicle battery assembly (200) from liquid inflow or outflow by providing a barrier between the portion of the vehicle battery assembly (200) and the outside of the battery tray (120). The various features that contribute to protecting a portion of the vehicle battery assembly (200) in this way are described in more detail below.

[0016] As most clearly shown in Figure 3, the battery tray (120) defines a base (122) and several wall sections (124, 128, 130, 132) extending upward from the base (122). The base (122) and the wall sections (124, 128, 130, 132) are formed from a single continuous material and define a rectangular box shape configured to receive a portion of the vehicle battery assembly (200) (e.g., battery cells (210)). Optionally, the upper parts of the wall sections (124, 128, 130, 132) define an upper edge (140) extending around the battery tray (120) and configured to connect a battery cover (110) to the battery tray (120).

[0017] The interfaces between the respective wall portions (124, 128, 130, 132), as well as the interface between the wall portions (124, 128, 130, 132) and the floor surface (122), typically have a curved, rounded, or radiused shape. As will be described later, the battery tray (120) is designed assuming forming by pressing. Therefore, in order to facilitate the ease of pressing, curved, rounded, or radiused joining surfaces or edges may be desirable.

[0018] The wall portions (124, 128, 130, 132) include a front wall portion (124), a rear wall portion (132), and a pair of side wall portions (128, 130) extending between the front wall portion (124) and the rear wall portion (132). Optionally, one or more of the wall portions (124, 128, 130, 132) define one or more openings (126) therein. The openings (126) may be desirable to allow one or more components (e.g., wires, cables, and / or others) of the vehicle battery assembly (200) to pass through the battery tray (120). In this embodiment, two openings are defined by the front wall portion (124). In other embodiments, various alternative configurations of the openings (126) may be used.

[0019] As best shown in FIG. 4, the battery tray (120) is formed of a multi-material construction. Specifically, the battery tray (120) includes a high-strength material (150) and a high formability material (160). The high-strength material (150) and the high formability material (160) are joined to form a single continuous part. The high-strength material (150) is typically configured to provide rigidity and strength to the battery tray (120), resist impacts from the sides and front, and provide ballistic protection. On the other hand, the high formability material (160) is typically configured to provide formability to a specific portion of the battery tray (120) and enable the battery tray (120) to be pressed from a flat blank.

[0020] The high-strength material (150) and the highly formable material (160) are positioned at specific locations on the battery tray (120) to provide an appropriate combination of rigidity, strength, and formability. For example, the high-strength material (150) forms the majority of the base surface (122) and extends to the front wall (124) and side walls (128, 130) to provide high strength and rigidity in areas of the battery tray (120) that are susceptible to frontal impacts (e.g., the front wall (124)), lateral impacts (e.g., the side walls (128, 130)), and ballistic impacts (e.g., the base surface (122)). On the other hand, the highly formable material (160) is positioned in areas of the battery tray (120) where bending stress may concentrate during press working. Therefore, in this embodiment, the highly moldable material (160) is positioned at the corners defined by the front wall (124), side walls (128, 130), and floor (122). Furthermore, the highly moldable material (160) defines the entire rear wall (132) and a portion of the floor (122) adjacent to the rear wall (132). In this embodiment, the high-strength material (150) and the highly moldable material (160) are positioned in specific locations, but it should be understood that in other embodiments, the arrangement of both materials may be altered by various factors. Such factors include the specific shape or structural configuration of the battery tray (120), or the specific vehicle application of the battery tray (120). For example, in some vehicle applications, rear-end collisions may also be considered. Therefore, in such applications, the rear wall (132) may have a material arrangement similar to that of the front wall (124) described above.

[0021] The high-strength material (150) and the highly formable material (160) are positioned at specific locations on the battery tray (120) to provide an appropriate combination of rigidity, strength, and formability. For example, the high-strength material (150) forms the majority of the floor surface (122) and extends to the front wall (124) and side walls (128, 130) to provide high strength and rigidity in areas of the battery tray (120) that are susceptible to frontal impacts (e.g., the front wall (124)), lateral impacts (e.g., the side walls (128, 130)), and ballistic impacts (e.g., the floor surface (122)). On the other hand, the highly formable material (160) is positioned in areas of the battery tray (120) where bending stress may concentrate during press working. Thus, in this embodiment, the highly formable material (160) is positioned at the corners defined by the front wall (124), side walls (128, 130), and floor surface (122). Furthermore, the highly moldable material (160) defines the entire rear wall (132) and a portion of the floor surface (122) adjacent to the rear wall (132). In this embodiment, the high-strength material (150) and the highly moldable material (160) are positioned in specific locations, but it should be understood that in other embodiments, the arrangement of both materials may be changed due to various factors. Such factors include the specific shape or structural configuration of the battery tray (120), or the specific vehicle application of the battery tray (120). For example, in some vehicle applications, rear-end collisions may also be considered. In such applications, the rear wall (132) may have a material arrangement similar to that of the front wall (124) described above.

[0022] The high-strength material (150) and the highly formable material (160) typically have a uniform thickness. For example, in this embodiment, both the high-strength material (150) and the highly formable material (160) have a thickness of approximately 2 mm. In other embodiments, the thickness can be varied depending on the specific materials used for the high-strength material (150) and the highly formable material (160). For example, if the high-strength material (150) has a higher (or lower) strength than M1700 grade steel, similar performance can be achieved by using thicknesses of less than 2 mm or more than 2 mm, respectively. Furthermore, or alternatively, the thickness of the highly formable material (160) can also be similarly varied depending on the formability characteristics of the specific material used. In yet another embodiment, the high-strength material (150) may specify a particular thickness, and the highly formable material (160) may specify a different thickness. As described above, by using such different thicknesses, it is possible to achieve equivalent performance while changing the specific materials used for the high-strength material (150) and / or the highly formable material (160).

[0023] High-strength material (150) and high-formability material (160) are typically joined by one or more welding processes. Such a joining provides a continuously sealed interface, making it possible to protect a portion of the vehicle battery assembly (200) from the ingress or egress of fluids. Various welding processes are available. For example, in one embodiment, high-strength material (150) and high-formability material (160) are joined by one or more melting welding processes, such as laser welding or arc welding. In another embodiment, high-strength material (150) and high-formability material (160) are joined by one or more forging processes, such as flash butt welding or friction stirring welding. In yet another embodiment, high-strength material (150) and high-formability material (160) are joined by a combination process of welding and forging.

[0024] Figure 5 shows an exemplary alternative battery tray (420) that can be incorporated into the battery storage structure (100) in place of the battery tray (120) described above. Similar to the battery tray (120) described above, the battery tray (420) of this embodiment defines a floor surface (422) and a number of wall sections (424, 428, 430, 432) extending upward from the floor surface (422). The floor surface (422) and the wall sections (424, 428, 430, 432) form a single continuous member, defining a rectangular box shape configured to receive a portion of the vehicle battery assembly (200) (e.g., battery cells (210)). Optionally, the upper parts of the wall sections (424, 428, 430, 432) are configured to define an upper edge (440) that extends around the battery tray (420) and to connect the battery cover (110) to the battery tray (420).

[0025] The joints between each wall section (424, 428, 430, 432), as well as the joints between the wall sections (424, 428, 430, 432) and the floor surface (422), generally have a curved, rounded, or radial shape. Similar to the battery tray (120) described above, the battery tray (420) of this embodiment is designed to be formed by press working. Therefore, to enhance the ease of press working, curved, rounded, or radially shaped joint surfaces and edges are desirable in some cases.

[0026] The wall sections (424, 428, 430, 432) include a front wall section (424), a rear wall section (432), and a pair of side wall sections (428, 430) extending between the front wall section (424) and the rear wall section (432). Optionally, one or more of the wall sections (424, 428, 430, 432) define one or more openings (426) within them. The openings (426) may be desirable to allow one or more components of the vehicle battery assembly (200) (e.g., wires, cables, and / or others) to pass through the battery tray (420). In this embodiment, the front wall section (424) defines two openings. In other embodiments, various alternative configurations of the openings (426) may be used.

[0027] As best illustrated in Figure 6, the battery tray (420) is formed from a multi-material construction. Specifically, the battery tray (420) comprises a high-strength material (450) and a highly formable material (460). The high-strength material (450) and the highly formable material (460) are joined together to form a single continuous part. The high-strength material (450) is generally configured to provide rigidity and strength to the battery tray (420), resisting impacts to the sides and front and providing ballistic protection. The highly formable material (460), on the other hand, is generally configured to provide formability to specific parts of the battery tray (420), allowing the battery tray (420) to be press-formed from a flat blank.

[0028] Similar to the battery tray (120) described above, the high-strength material (450) and the highly moldable material (460) are positioned at specific locations on the battery tray (420) to provide an appropriate combination of rigidity, strength, and moldability. However, unlike the battery tray (120) described above, the high-strength material (450) and the highly moldable material (460) are separated and positioned in different areas of the battery tray (420), providing different performance characteristics to the battery tray (120). For example, the high-strength material (450) defines most of the floor surface (422) and terminates before intersecting the walls (424, 428, 430, 432) or the curved interfaces associated with the walls (424, 428, 430, 432). In other words, in this embodiment, the high-strength material (450) is generally limited to the floor surface (422). In this embodiment, the high-strength material (450) forms most of the floor surface (422). In some embodiments, the high-strength material (450) covers more than 60% of the floor surface (422) area. In other embodiments, the high-strength material (450) covers more than 80% of the floor surface (422) area. In yet another embodiment, the high-strength material (450) covers more than 90% of the floor surface (422) area. In yet another embodiment, the high-strength material (450) covers the entire portion of the floor surface (422) that is not subjected to bending forces during press working. In such embodiments, the high-strength material (430) defines a substantially flat or planar portion of the floor surface (422), and the highly formable material (460) defines a non-flat or non-planar portion of the floor surface (422).

[0029] The highly formable material (460) is placed in areas of the battery tray (420) where bending stress may concentrate during stamping. Therefore, in this embodiment, the highly formable material (460) is placed at the corners defined by the front wall (124), side walls (128, 130), and floor surface (122), as well as at the interfaces between the floor surface (422) and the walls (424, 428, 430, 432). Furthermore, the highly formable material (460) defines the entirety of the front wall (424), the rear wall (432), and at least a portion of the floor surface (422) adjacent to each wall (424, 428, 430, 432). The configuration of the high-strength material (450) and the highly formable material (460) in this embodiment is generally desirable, particularly for controlling the distortion of the battery tray (420) during and after press working. By limiting the use of high-strength material (450) to the floor surface (422), the material properties in areas subjected to bending forces are kept more uniform, and areas potentially subjected to impact are reinforced using high-strength material (450).

[0030] High-strength materials (450) and highly formable materials (460) generally include different grades of steel. For example, in this embodiment, high-strength materials (450) include M1500 or M1700 grade steel. In other embodiments, high-strength materials (450) include Advanced High-Strength Steel (AHSS) grade or Ultra High-Strength Steel (UHSS) grade. Similarly, in this embodiment, highly formable materials (460) include soft steel grades such as CR5 grade steel. In other embodiments, highly formable materials (460) include other soft steel grades. Alternatively, in some embodiments, high-strength materials (450) and / or highly formable materials (460) may include one or more press-hardened steels (PHS) of various grades. For example, in one embodiment, high-strength materials (450) include PHS material grades of 1500 MPa or higher, and highly formable materials (460) include PHS material grades of less than 1500 MPa. In such embodiments, the high-strength material (450) and the highly moldable material (460) are arranged as described herein to provide a desired change in material properties. In yet another embodiment, the battery tray (420) may be a monolithic structure of the PHS material.

[0031] Both the high-strength material (450) and the highly formable material (460) typically have a uniform thickness. For example, in this embodiment, both the high-strength material (450) and the highly formable material (460) have a thickness of approximately 2 mm. In other embodiments, the thickness can be varied depending on the specific materials used for the high-strength material (450) and the highly formable material (460). For example, if the high-strength material (450) is stronger or weaker than M1500 or M1700 grade steel, a thickness thinner or thicker than 2 mm, respectively, can be used, and similar performance can still be achieved. Furthermore, or alternatively, the thickness of the highly formable material (460) can also be similarly varied depending on the formability characteristics of the specific material used. In yet another example, the high-strength material (450) may specify one thickness, and the highly formable material (460) may specify another. Similarly, as previously mentioned, it is possible to change the specific materials used for the high-strength material (450) and / or the highly formable material (460) while achieving equivalent performance using such different thicknesses.

[0032] High-strength material (450) and high-formability material (460) are typically joined by one or more welding processes. Such a joining provides a continuously sealed interface, making it possible to protect a portion of the vehicle battery assembly (200) from the ingress or egress of fluids. Various welding processes are available. For example, in one embodiment, the high-strength material (450) and high-formability material (460) are joined by one or more fusion welding processes, such as laser welding or arc welding. In another embodiment, the high-strength material (450) and high-formability material (460) are joined by one or more forging processes, such as flash butt welding or friction stirring welding. In yet another embodiment, the high-strength material (450) and high-formability material (460) are joined by a combination process of welding and forging.

[0033] The joining of high-strength material (450) and highly formable material (460) can be carried out in various patterns using a variety of welding paths. For example, Figure 7 shows a blank (510) that can be used to form a battery tray (420). The blank (510) includes an example of a joining configuration. In this configuration, the blank (510) is formed by two relatively long, continuous horizontal welds (520) and two relatively short, continuous vertical welds (522). Furthermore, the vertical welds (522) intersect and terminate at their respective corresponding horizontal welds (520). For ease of manufacturing, the highly formable material (460) can be divided into four or more segments, including two relatively long upper and lower segments (512, 516) and two relatively short side segments (514). In this configuration, the side segments (514) are positioned between the upper segment (512) and the lower segment (516). All segments (512, 514, 516) are roughly rectangular with slightly rounded corners. These segments (512, 514, 516) can be directly welded to a single, roughly rectangular central segment (518) containing high-strength material (450).

[0034] Figure 8 shows another blank (530) that can be used to form a battery tray (420). The blank (530) includes an alternative joining configuration as an example only. In this configuration, the blank (530) is formed by two relatively long, continuous horizontal welds (540) and two relatively long, continuous vertical welds (542). Furthermore, the horizontal welds (540) intersect and terminate at each of the vertical welds (542). To enhance manufacturability, the highly formable material (460) can be divided into four or more segments, including an upper segment (532), a lower segment (536), and two side segments (534). In this configuration, the upper segment (532) and the lower segment (536) are positioned between the side segments (534). All segments (532, 534, 536) are roughly rectangular with slightly rounded corners. These segments can be directly welded to a single, roughly rectangular intermediate segment (538) containing high-strength material (450).

[0035] Example 1 Figure 9 shows a first test battery tray (320) prepared in substantially the same manner as the battery tray (120) described above. Similar to the battery tray (120), the first test battery tray (320) was prepared to include a base (322) and a front wall (324), side walls (328, 330), and a rear wall (332) extending upward from the base (322). The first test battery tray (320) was prepared with a multi-material composition including a high-strength material (350) of M1700 grade steel and a highly formable material (360) of CR5 grade steel. The high-strength material (350) and the highly formable material (360) were placed in the same positions as the high-strength material (150) and the highly formable material (160) described above. The thickness of both the high-strength material (350) and the highly formable material (360) was approximately 2 mm.

[0036] A computer-generated model of the first test battery tray (320) was generated using ATUOFORM software, which simulates press working. Subsequently, the press working of the computer-generated model of the first test battery tray (320) was simulated using the ATUOFORM software. A heatmap of the forces generated during the simulated press working operation was generated using the software and is reproduced in Figure 10. A successful press working operation was observed.

[0037] Example 2 Next, a digital simulation of ballistic impact on the floor surface (322) was performed using the computer-generated model of the first test battery tray (320). A heatmap of the forces generated during the simulated ballistic impact was generated and reproduced in Figure 11. Furthermore, a force-to-displacement curve for the computer-generated model of the first test battery tray (320) was generated and reproduced in Figure 12. One of the ballistic impact criteria is to avoid contact with the vehicle battery assembly (200) before the load from a 20mm bullet-shaped rigid impact body reaches 35kN. Based on the heatmap reproduced in Figure 11 and the force-to-displacement curve reproduced in Figure 12, it was confirmed that this criterion was met.

[0038] Example 3 Figure 13 shows a second test battery tray (620) prepared in substantially the same manner as the battery tray (420) described above. Similar to the battery tray (420), the second test battery tray (620) was prepared to include a base (622) and a front wall (624), side walls (628, 630), and a rear wall (632) extending upward from the base (622). The second test battery tray (620) was also prepared with a composite material configuration including M1500 grade steel as the high-strength material (650) and mild steel as the highly formable material (660). The high-strength material (650) and the highly formable material (660) were placed in the positions described above for the high-strength material (450) and the highly formable material (460). The thickness of both the high-strength material (650) and the highly formable material (660) was approximately 2 mm.

[0039] A computer-generated model of the second test battery tray (620) was generated using ATUOFORM software, which is software for digitally simulating press working. Next, the press working of the computer-generated model of the second test battery tray (620) was simulated using the ATUOFORM software. A heat map of the forces generated during the simulated press working operation was generated using the software and reproduced in Figure 14. The success of the press working operation was confirmed.

[0040] Example 4 Next, using a computer-generated model of the second test battery tray (620), a digital simulation of ballistic impact on the floor surface (622) was performed using software called HyperMesh & LS-DYNA. A heatmap of the forces generated during the simulated ballistic impact was generated and reproduced in Figure 15. Furthermore, a force-to-displacement curve was generated for the computer-generated model of the second test battery tray (620) and reproduced in Figure 16. One of the ballistic impact criteria is to avoid contact with the vehicle battery assembly (200) before the load reaches 35kN when a rigid impact body with a diameter of 20mm is applied. Based on the heatmap reproduced in Figure 15 and the force-to-displacement curve reproduced in Figure 16, it was confirmed that this criterion was met.

[0041] Example 5 A physical sample of the second test battery tray (620) was prepared, and its flatness was evaluated. Specifically, the variation in flatness was measured for a flange structure similar to that of the upper edge (440) mentioned above. The variation in flatness was measured using a coordinate measuring machine. It was confirmed that the flatness was within ±1.5 mm over the entire length of 2,100 mm.

[0042] Example 6 Next, a leak test was performed on the physical sample of Example 5. In the leak test, the physical sample was placed in a tank with the open side facing downwards. The flange structure of the physical sample was in contact with a gasket placed on a plate simulating a structure such as a battery cover (110). The inside of the actual sample was pressurized to 0.5 psi. The tank was filled with water. No leaks were observed after more than 15 minutes, meaning the leak rate was 0 standard cubic centimeters per minute (SCCM) (the permissible limit is a maximum of 15 SCCM).

[0043] Example 7 A device for housing a portion of a vehicle battery assembly, the device having a tray configured to receive the portion of the vehicle battery assembly, the tray defining a floor, a front wall, a rear wall, and a pair of side walls extending from the front wall to the rear wall, the tray comprising a first steel member and a second steel member, the first steel member joined with the second steel member to form a single continuous part, the first steel member defining most of the floor, and the second steel member positioned at two or more corners of the tray.

[0044] Example 8 In the apparatus of Embodiment 7, the tray defines one or more openings, and each of the one or more openings is configured to receive a part of the vehicle battery assembly.

[0045] Example 9 The apparatus of Example 7 or 8 further comprises a cover, wherein the tray is configured to receive the cover.

[0046] Example 10 In the apparatus of Embodiment 9, the tray defines edges extending from the front wall, the rear wall, and the pair of side walls, and the edges are configured to fit with the cover.

[0047] Example 11 In any of the apparatuses of Examples 7 to 10, the first steel material and the second steel material are joined by welding.

[0048] Example 12 In the apparatus of Example 7, the welding is either welding or forge welding.

[0049] Example 13 An apparatus according to any of Examples 7 to 12, wherein the second steel material is positioned at each corner defined by the interface with the floor surface, the front wall portion, and the pair of side wall portions.

[0050] Example 14 In any of the devices in Examples 7 to 13, the second steel material defines the entire back wall portion.

[0051] Example 15 In any of the apparatuses in Examples 7 to 13, the second steel material defines the back surface of the floor.

[0052] Example 16 The apparatus according to any of Examples 7 to 15, wherein the first steel material includes a first steel grade, the second steel material includes a second steel grade, and the first steel grade is different from the second steel grade.

[0053] Example 17 An apparatus according to any of Examples 7 to 15, wherein the first steel material includes the first steel grade, the second steel material includes the second steel grade, the first steel grade is an ultra-high-strength steel grade or an advanced high-strength steel grade, and the second steel grade is a mild steel grade.

[0054] Example 18 The apparatus is according to any of Examples 7 to 15, wherein the first steel material includes the first steel grade, the second steel material includes the second steel grade, and the first steel grade is M1700 grade steel or M1500 grade steel.

[0055] Example 19 The apparatus of Example 18 is such that the second steel grade is CR5 grade steel.

[0056] Example 20 In any of the apparatuses of Examples 7 to 19, the first steel material defines a substantially flat portion of the floor surface.

[0057] Example 21 The apparatus according to any of Examples 7 to 19, wherein the first steel member defines the flat portion of the floor, and the second steel member defines the non-planar portion of the floor surface.

[0058] Example 22 The apparatus of Example 21 is such that the first steel material is insulated from the floor surface.

[0059] Example 23 A method for housing a portion of a vehicle battery assembly in a tray, the method comprising the steps of: welding a first steel material to a second steel material to form a single continuous steel plate; press-forming the single continuous steel plate to form a tray; and inserting the portion of the vehicle battery assembly into the hollow interior of the formed tray, wherein the formed tray has a hollow interior.

[0060] Example 24 The method of Example 23 further includes a step of positioning the first steel material and the second steel material relative to each other before welding, wherein the second steel material is positioned at one or more corners of the first steel material.

[0061] Example 25 In the method of Example 24, the step of positioning the first steel material and the second steel material relative to each other includes the step of positioning the first portion of the second steel material to the first corner of the first steel material, and positioning the second portion of the second steel material to the second corner of the first steel material.

[0062] Example 26 In the method of Example 25, the step of positioning the first steel material and the second steel material relative to each other includes the step of positioning the third portion of the second steel material to the end of the first steel material opposite to the first corner and the second corner.

[0063] Example 27 In any of the methods in Examples 23 to 26, the welding step includes the step of forming one or more continuous welds between the first steel material and the second steel material.

[0064] Example 28 In any of the methods in Examples 23 to 27, the welding step includes welding the first steel material to the second steel material using a fusion welding process.

[0065] Example 29 In the method of Example 28, the fusion welding process includes laser welding or arc welding.

[0066] Example 30 In any of the methods in Examples 23 to 27, the welding step includes welding the first steel material to the second steel material using a forging welding process.

[0067] Example 31 In the method of Example 30, the forging process includes friction stirring welding or flash butt welding.

[0068] Example 32 A device for housing a portion of a vehicle battery assembly, the device comprising a battery cover and a battery tray, the battery tray comprising a front wall, a rear wall, a pair of side walls, and a floor, the front wall, the rear wall, and the pair of side walls extending upward from the floor, defining an interface between the front wall, the rear wall, the pair of side walls, and the floor, the front wall, the rear wall, and the pair of side walls collectively defining an upper edge, the upper edge configured to receive a battery cover and form a cavity for housing a portion of a vehicle battery assembly, the battery tray being constructed by joining a high-strength material and a highly moldable material to form a single tray, the high-strength material defining a portion of the floor, and the highly moldable material defining the front wall, the rear wall, the pair of side walls, and the interface.

[0069] Having shown and described various embodiments of the present invention, further adaptations of the methods and systems described herein can be achieved without departing from the scope of the invention by appropriate modifications by those skilled in the art. Some of such potential modifications have already been mentioned, and others will be obvious to those skilled in the art. For example, the examples, embodiments, geometry, materials, dimensions, proportions, processes, etc., discussed above are illustrative and not essential. Therefore, the scope of the invention should be considered based on any claims that may be presented and is understood to be not limited to the details of the structure and operation shown and described in the specification and drawings.

Claims

1. A device for housing a portion of a vehicle battery assembly, A tray configured to receive the portion of the vehicle battery assembly, the tray comprising a floor, a front wall, a rear wall, and a pair of side walls extending from the front wall to the rear wall, A tray comprising a first steel member and a second steel member, wherein the first steel member is joined with the second steel member to form a single continuous part, the first steel member defines most of the floor surface, and the second steel member is positioned at two or more corners of the tray. A device having.

2. The apparatus according to claim 1, wherein the tray defines one or more openings, and each of the one or more openings is configured to receive a part of the vehicle battery assembly.

3. In the apparatus according to claim 1 or 2, further, The cover and, The tray and A device having the following features.

4. The apparatus according to claim 3, wherein the tray defines edges extending from the front wall, the rear wall, and the pair of side walls, and the edges are configured to fit with the cover.

5. The apparatus according to any one of claims 1 to 4, wherein the first steel material and the second steel material are joined by welding.

6. The apparatus according to claim 1, wherein the welding is melting or forging welding.

7. The apparatus according to any one of claims 1 to 6, wherein the second steel material is arranged at each corner defined by the interface between the floor surface, the front wall portion, and the pair of side wall portions.

8. The apparatus according to any one of claims 1 to 7, wherein the second steel material defines the entire rear wall portion.

9. The apparatus according to any one of claims 1 to 7, wherein the second steel material defines the rear portion of the floor surface.

10. An apparatus according to any one of claims 1 to 7, wherein the first steel material includes a first type of steel, the second steel material includes a second type of steel, and the first type of steel is different from the second type of steel.

11. An apparatus according to any one of claims 1 to 9, wherein the first steel material comprises a first steel grade, the second steel material comprises a second steel grade, the first steel grade is an ultra-high-strength steel grade or an advanced high-strength steel grade, and the second steel grade is a mild steel grade.

12. An apparatus according to any one of claims 1 to 9, wherein the first steel material includes a first steel grade, the second steel material includes a second steel grade, and the first steel grade is M1700 grade steel.

13. In the apparatus according to any one of claims 1 to 9, the first steel material includes a first steel grade, the second steel material includes a second steel grade, and the first steel grade is M1700 grade steel or M1500 grade steel.

14. In the apparatus according to claim 13, the second steel grade is CR5 grade steel.

15. The apparatus according to any one of claims 1 to 14, wherein the first steel material defines a substantially flat portion of the floor surface.

16. An apparatus according to any one of claims 1 to 14, wherein the first steel material defines the planar portion of the floor surface, and the second steel material defines the non-planar portion of the floor surface.

17. The apparatus according to claim 16, wherein the first steel material is isolated from the floor surface.

18. A method for housing a portion of a vehicle battery assembly in a tray, A process of welding a first steel material to a second steel material in order to form a single continuous steel plate, A step of forming the tray by press working the single continuous steel plate, wherein the formed tray has a hollow interior, and the forming step, A step of inserting a part of the vehicle battery assembly into the hollow interior of the formed tray. A method having

19. In the method according to claim 18, further, A method comprising the step of positioning the second steel material at one or more corners of the first steel material before welding, and positioning the first steel material and the second steel material relative to each other.

20. A method according to claim 19, wherein the step of positioning the first steel material and the second steel material relative to each other includes the steps of positioning a first portion of the second steel material at a first corner of the first steel material and positioning a second portion of the second steel material at a second corner of the first steel material.

21. A method according to claim 20, wherein the step of positioning the first steel material and the second steel material relative to each other includes the step of positioning the third portion of the second steel material on the edge of the first steel material opposite to the first corner and the second corner.

22. A method according to any one of claims 18 to 21, wherein the welding step includes the step of forming one or more continuous welds between the first steel material and the second steel material.

23. A method according to any one of claims 18 to 22, wherein the welding step includes welding the first steel material to the second steel material using a melting welding process.

24. A method according to claim 23, wherein the melting welding process includes laser welding or arc welding.

25. A method according to any one of claims 18 to 22, wherein the welding step includes welding the first steel material to the second steel material using a forging welding process.

26. A method according to claim 25, wherein the forging welding process includes friction stirring welding or flash butt welding.

27. A device for housing a portion of a vehicle battery assembly, (a) Battery cover and, (b) A battery tray comprising a front wall, a rear wall, a pair of side walls, and a floor, wherein the front wall, the rear wall, and the pair of side walls extend upward from the floor, defining an interface between the front wall, the rear wall, the pair of side walls, and the floor, and the front wall, the rear wall, and the pair of side walls together define an upper edge, the upper edge being configured to receive the battery cover and form a cavity for receiving a portion of the vehicle battery assembly, and It has, The battery tray is formed by joining a high-strength material and a highly moldable material to create a single tray, the high-strength material defining at least a portion of the floor surface, and the highly moldable material defining the front wall, the rear wall, the pair of side walls, and the interface. Device.

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