Front vehicle-body structure for vehicle equipped with battery unit

Abstract

The invention provides a front vehicle body structure of a vehicle, which can properly ensure the function of a torque box and increase the capacity of a battery unit. A torque box (70) having a closed cross-sectional structure formed by attaching a box panel (71) to the lower surface of the front end portion of a floor panel (8) and connecting the rear end portions (5b) of the left and right front side frames (5) and the front end portions of the side members (6) in cooperation with the floor panel (8) is provided. The battery unit (30) has a rectangular appearance in plan view, and is disposed below the floor panel (8) so as to extend along the floor panel (8). The torque box (70) is housed in a step portion (68) provided at the tip portion of the battery cell (30), so that the tip portion of the battery cell (30) and the torque box (70) are disposed so as to overlap each other up and down.

Description

Technical Field

[0001] The present disclosure discloses a front body structure for an electric vehicle or similar vehicle, which is equipped with a battery unit for driving. Background Technology

[0002] Patent document 1 discloses this front body structure.

[0003] In the front body structure of Patent Document 1, a pair of left and right front side frames are connected to a crossbeam extending along the vehicle width direction. The left and right ends of the crossbeam are respectively connected to the pair of left and right side beams via external brackets.

[0004] Each outer bracket has an inclined surface on its inner side in the vehicle width direction, which slopes outwards as it moves further back in the vehicle width direction. Inclined surfaces are also provided at the left and right front corners of the battery casing. These inclined surfaces and the inclined surfaces of each outer bracket are configured to be opposite each other via gaps.

[0005] Prior art literature

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2019-18821

[0008] The technical problem that the invention aims to solve

[0009] Battery cells are heavy and have a large capacity. Therefore, battery cells are typically installed extending beneath a large floor panel.

[0010] However, the space beneath the floor panel is limited in height. Therefore, the battery cells must be larger horizontally. Conversely, there is a pair of front side rails at the front of the vehicle to prevent loads from acting from the front.

[0011] To transfer the load to a pair of rearward side beams, the vehicle body structure of Patent Document 1 includes a crossbeam and an outer bracket. Consequently, the left and right front corner portions of the battery cell in Patent Document 1 are cut off when viewed from above. In the vehicle body structure of Patent Document 1, this portion reduces the capacity of the battery cell, which is disadvantageous.

[0012] On the other hand, there are cases where the loads of each front side frame are transferred to each side beam via a torque box with a closed cross-section structure that has excellent strength and rigidity. In order to properly perform the load transfer function, the torque box needs to be constructed with an appropriate volume and a small deviation in the aspect ratio of the closed cross-section.

[0013] Therefore, if the battery cell is enlarged forward, it will interfere with the torque box. Thus, similar to the vehicle body structure in Patent Document 1, the battery cell must be positioned away from the torque box. This results in a reduction in the battery cell's capacity. Summary of the Invention

[0014] Therefore, this specification discloses a technique that can properly ensure the function of the torque box and can expand the battery cell forward to increase its capacity.

[0015] Technical means for solving technical problems

[0016] The technical design disclosed herein relates to the front body structure of a vehicle in which a battery unit is mounted.

[0017] The front body structure includes: a floor panel that forms the floor of the vehicle's cabin; a pair of side beams that extend in a longitudinal direction along the left and right side edges of the floor panel; a pair of front side brackets that extend forward separately from the front side of the floor panel; and a torque box having a closed cross-section structure formed by mounting a box panel on the lower surface of the front end portion of the floor panel, and the torque box cooperating with the floor panel to connect the rear ends of the left and right front side brackets to the front ends of the side beams.

[0018] The battery unit has a rectangular appearance when viewed from above and is arranged below the floor panel in a manner that extends along the floor panel. Furthermore, by providing a step portion at the front end of the battery unit that is lower than the upper surface of the battery unit, and housing the torque box in the step portion, the front end of the battery unit and the torque box are arranged in a manner that overlaps vertically.

[0019] That is, according to this front body structure, a torque box with a closed cross-section structure is formed by mounting a box panel on the lower surface of the front end portion of the floor panel. This torque box cooperates with the floor panel to connect the rear ends of the left and right front side frames to the front ends of the side beams.

[0020] Furthermore, the battery unit, which is positioned below the floor panel and extends along the floor panel, has a rectangular appearance when viewed from above. By providing a step at the front end of the battery unit that is lower than the upper surface of the battery unit, and housing the torque box in this step, the front end of the battery unit and the torque box are arranged to overlap vertically.

[0021] This allows the battery cell to be formed into a rectangle approximately the same size as the floor panel. It ensures the function of the torque box and allows the battery cell to be expanded forward to achieve a large-capacity battery cell.

[0022] Alternatively, the torque box may have a front wall facing forward, a rear wall facing backward, and a lower wall facing downward, with the stepped portion formed along the lower wall and the rear wall.

[0023] This ensures the proper closed cross-sectional shape of the torque box and maximizes the capacity at the front end of the battery cell.

[0024] Alternatively, the torque box may also have a sidewall facing to the side, and the torque box may engage with the front end of the side beam from multiple directions.

[0025] In this way, the load acting on the torque box can be reliably and properly transferred to the side beam.

[0026] Alternatively, both ends of the rear end of the front side frame can be engaged with the torque box via the front wall portion.

[0027] In this way, the torque box bears the load transmitted from the front side frame to the rear, thus reliably and properly transmitting the load acting on the front side frame to the torque box.

[0028] Alternatively, the battery cell may have a battery housing that houses a single battery cell. The battery housing may have a rectangular frame member, a bottom member, and a cover member, which are mounted on the frame member to cover the top and bottom of the single battery cell. The stepped portion is formed by the frame member opposite to the lower wall and the cover member opposite to the rear wall. The frame member is fixed to the lower wall.

[0029] In this way, the battery cell is supported by a frame component with excellent strength and rigidity on a torque box with equally excellent strength and rigidity, thus enabling stable support of the battery cell.

[0030] Alternatively, the lower surface of the floor panel containing the torque box may be opposite the upper surface of the battery housing containing the frame member and the cover member, separated by a predetermined gap.

[0031] The battery cell dissipates heat during use. If there is a gap between the floor panel or similar surface and the upper surface of the battery casing, a large surface area for heat dissipation can be ensured above the battery cell. This promotes heat dissipation from the battery cell.

[0032] The effects of the invention

[0033] According to the technology disclosed herein, the function of the torque box can be properly ensured, and the battery cell can be extended forward to increase its capacity. Attached Figure Description

[0034] Figure 1 This is a diagram showing the vehicle body structure using the technology disclosed herein, viewed from above.

[0035] Figure 2 It is from Figure 1 A 3D view viewed in the direction of arrow A.

[0036] Figure 3 yes Figure 1 The sectional view at the arrow BB line in the image.

[0037] Figure 4 yes Figure 3 The sectional view at the arrow DD line in the image.

[0038] Figure 5 It is from Figure 4 The diagram shows the direction of arrow E.

[0039] Figure 6 yes Figure 1 The sectional view at the CC line (arrow) in the diagram.

[0040] Figure 7A This is a diagram used to illustrate the structure of a battery cell.

[0041] Figure 7B This is a diagram used to illustrate the structure of a battery cell.

[0042] Figure 8 This is a diagram used to illustrate the structure of the box panel.

[0043] Figure 9 It is a 3D view showing the box panel installed on the vehicle body.

[0044] Symbol Explanation

[0045] 1. Body

[0046] 2. Bumper beam

[0047] 3. Upper beam of the protective cover

[0048] 4. Beams

[0049] 5. Front side frame

[0050] 5b Rear end

[0051] 6 side beams

[0052] 7. Dashboard

[0053] 8 Floor panels

[0054] 8a Tilting the face upwards

[0055] 8b Drum section

[0056] 11 Suspension shell

[0057] 12 Energy Absorbing Boxes

[0058] 30 battery cells

[0059] 30A battery cell

[0060] 30b Battery casing

[0061] 40 Battery Frame

[0062] 41 Frame Components

[0063] 41a First frame component

[0064] 41b Second frame component

[0065] 42 Support section

[0066] 45 Reinforced Components

[0067] 50 bottom components

[0068] 60 Cover components

[0069] 61 upper surface

[0070] 62 Side surface portion

[0071] 63 Flange face

[0072] 64. Platform-shaped section

[0073] 65. Tilting the face downwards

[0074] 68 Steps

[0075] 70 Torque Box

[0076] 71 box panels

[0077] 71a Anterior wall portion

[0078] 71b Rear wall portion

[0079] 71c Lower wall portion

[0080] 71d Sidewall

[0081] 72. Secure the base. Detailed Implementation

[0082] The technology disclosed herein is described below. However, this description is merely illustrative in nature. The front-back, left-right, and up-down directions used in the description are based on the vehicle. These directions are indicated by arrows in the figures. The left-right direction corresponds to the vehicle width direction.

[0083] <Body Structure>

[0084] Figures 1 to 6An example of a vehicle body structure in which the technology of this disclosure is applied is given. Figure 1 This is a top view (view from above) of the vehicle body 1. Figure 2 It is from Figure 1 A 3D view viewed in the direction of arrow A. Figure 3 yes Figure 1 The sectional view at the arrow BB line in the image. Figure 4 yes Figure 3 The sectional view at the arrow DD line in the image. Figure 5 It is from Figure 4 The diagram showing the direction of arrow E (bottom surface view). Figure 6 yes Figure 1 The sectional view at the CC line (arrow line) in the diagram. These... Figures 1 to 6 The body of the car body 1 is simplified.

[0085] The body 1 consists of bumper beam 2, upper guard beam 3, side beam 4, front side frame 5, side beam 6, instrument panel 7, floor panel 8, etc.

[0086] This vehicle is an electric vehicle. It is driven by an electric motor. Although not shown, the motor is mounted in the front side space 1a located at the front of the vehicle body 1. A passenger compartment 1b is formed in the middle part of the vehicle body 1. A floor panel 8, which is roughly rectangular when viewed from above, is laid in the middle part of the vehicle body 1 in both the front-to-back and left-to-right directions (horizontal direction). The floor panel 8 forms the bottom surface of the passenger compartment 1b.

[0087] The battery unit 30, installed in the vehicle, serves as the power source for the motor that drives the vehicle. The battery unit 30 is required to have high output. Therefore, the battery unit 30 is heavy and has a large capacity. However, the installation space in the vehicle is limited. Therefore, as... Figure 1 As shown by the dashed line, the battery unit 30 is arranged below the floor panel 8 in a manner that extends along the floor panel 8.

[0088] The battery unit 30 of this vehicle, by applying the technology disclosed herein, has a rectangular appearance in top view, which is substantially the same as that of the floor panel 8. In particular, it is noteworthy that its front end is located near the front edge of the floor panel 8. The left and right front corner portions of the battery unit 30 overlap vertically with the left and right front corner portions of the floor panel 8. The battery unit 30 will be described further later.

[0089] like Figure 2 As shown, the front space 1a and the cabin 1b are separated by a dashboard 7 that extends in both vertical and horizontal directions. Figure 3 As shown, the front end of the floor panel 8 is provided with an upwardly inclined surface 8a that slopes upwards as it moves forward.

[0090] The protruding end of the upwardly sloping face 8a is connected to the lower end of the instrument panel 7. The instrument panel 7 and the floor panel 8 are formed into one piece by joining multiple steel plates formed by stamping. The lower part of the instrument panel 7 is provided with a raised strip 7a that extends to the left and right in a forward-protruding state.

[0091] A reinforcing rib 7b forming a closed cross-section structure is provided on the rear side of the protruding rib portion 7a. A bulge portion 8b extending rearward in a strip shape is formed at the center of the front end portion of the floor panel 8 in the left-right direction. Torque boxes 70 (described in detail later) are installed on the left and right sides of the bulge portion 8b on the lower surface of the floor panel 8 via upwardly inclined surfaces 8a.

[0092] A pair of side beams 6, 6 with excellent strength and rigidity are provided on the left and right sides of the middle section of the vehicle body 1. Each side beam 6 is composed of column-shaped components, which extend parallel to each other in the front-rear direction along the left and right sides of the floor panel 8. A rear side frame 9 extending rearward is connected to the rear end of each side beam 6. A rear floor panel 9a connected to the floor panel 8 is laid between these rear side frames 9, 9.

[0093] like Figure 1 , Figure 2 , Figure 3 As shown, a pair of front side frames 5, 5 extend forward from the left and right sides of the front of the floor panel 8. Each front side frame 5 is composed of a columnar member with a rectangular cross-section and has a main body 5a extending horizontally and a rear end 5b extending downward from the rear end of the main body 5a and being shorter.

[0094] Each front side frame 5 engages with the upwardly inclined surface 8a of the floor panel 8 and the torque box 70 via the rear end 5b. For example... Figure 1 , Figure 2 As shown, in the left-right direction, the joint of these rear ends 5b is located between the center of the vehicle body 1 and the middle of each of the left and right side ends. Furthermore, when viewed from the top and bottom, the pair of front side frames 5, 5 are arranged at a slight angle, becoming more separated as they move forward.

[0095] Suspension housings 11 are provided on the front sides of the left and right ends of the instrument panel 7. The lower end of each suspension housing 11 is connected to the front side frame 5. A side beam 4 is connected to the upper end of each suspension housing 11.

[0096] Each side beam 4 extends forward from the outside of each suspension housing 11. Each side beam 4 bends inward toward the vehicle width as it moves forward. The tops of a pair of side beams 4 are connected by an upper beam 3 of a shroud extending in the left-right direction.

[0097] Below and in front of the upper beam 3 of the guard, there is a bumper beam 2 extending in the left-right direction. The front ends of each front side frame 5 are connected to both ends of the bumper beam 2 via energy-absorbing boxes 12.

[0098] <Battery Unit>

[0099] Figure 7A , Figure 7B The structure of the battery cell 30 is illustrated. The battery cell 30 has a plurality of battery cells 30a and a battery casing 30b that houses these battery cells 30a.

[0100] Each battery cell 30a is constructed by connecting multiple lithium-ion batteries. All battery cells 30a are electrically connected to enable the output of a specified high voltage. Each battery cell 30a is formed into a rectangular block (cubic parallelepiped) shape to consider the loading efficiency into the battery casing 30b. In this battery unit 30, 12 battery cells 30a are arranged in a horizontally close manner, with four in the left-right direction and three in the front-back direction, inside the battery casing 30b.

[0101] The battery casing 30b includes a battery frame 40, a bottom component 50, a cover component 60, etc. The battery frame 40 has a rectangular frame component 41 and a plurality of reinforcing components 45. The frame component 41 and the reinforcing components 45 are made of square tubes with a specified cross-sectional shape. They are formed by extruding aluminum.

[0102] The frame component 41 has a pair of first frame components 41a, 41a facing each other left and right, and a pair of second frame components 41b, 41b facing each other front and back. Each second frame component 41b has a rectangular cross-section that is internally divided. At two predetermined locations symmetrically positioned on the front second frame component 41b (also referred to as the front second frame component 41b), there are front fastening portions 31 for fastening to the torque box 70 (details will be described later).

[0103] On the other hand, each first frame member 41a has an inverted L-shaped cross-section internally divided, and a support portion 42 extending outwards is provided on its upper part. Side fastening portions 32 for fastening to the side beam 6 are provided at multiple spaced intervals along the long side direction of the support portion 42. Additionally, as... Figure 7B As shown in the enlarged view, the frame component 41 has threaded fixing parts 33 for threaded fixing of the cover component 60 at multiple locations.

[0104] The reinforcing member 45 also has a rectangular cross-section internally divided. In the case of this battery cell 30, there are three reinforcing members 45. Each reinforcing member 45 extends parallel to a pair of first frame members 41a, 41a. Each reinforcing member 45 is mounted between the front and rear second frame members 41b, 41b in a manner that passes between the battery cells 30a.

[0105] The bottom component 50 and the cover component 60 are formed by stamping aluminum sheets. The bottom component 50 is joined (welded) to the lower surface of the frame component 41 in such a way that it covers the lower side of the battery cell 30a. The cover component 60, which covers the upper side of the battery cell 30a, is fastened to the upper surface of the frame component 41.

[0106] The cover component 60 has a tray-like appearance with an opening facing downwards. Specifically, when viewed from above, it has: a rectangular upper surface portion 61, a frame-like side surface portion 62 whose upper edge is connected to the periphery of the upper surface portion 61, and a flange portion 63 extending from the lower edge of the side surface portion 62 to its periphery.

[0107] A platform-shaped portion 64 is formed on the rear side of the cover member 60. This platform-shaped portion 64 extends along the rear edge of the cover member 60 and is formed by rising a section from the upper surface portion 61. Although not shown, this platform-shaped portion 64 houses electrical components such as a control device for controlling the battery unit 30 and a power input / output device. The left and right side surface portions 62 are formed in a manner that hangs down from the upper surface portion 61. On the other hand, the front-facing side surface portion 62 is formed in a manner that slopes downward towards the front (also referred to as a downwardly sloped surface portion 65).

[0108] At multiple locations on the flange face 63, threaded fastening holes 66 are formed corresponding to the arrangement of the threaded fixing portions 33 of the frame member 41. By fastening the threaded members 67 inserted into each fastening hole 66 to the threaded fixing portions 33, the cover member 60 can be detachably mounted to the frame member 41.

[0109] By mounting the cover member 60 to the frame member 41, a step portion 68 is formed at the front end of the battery unit 30, which is lower in height than the upper surface 61 of the battery unit 30. In detail, the step-shaped portion, which is lower in height than the upper surface 61, is formed by the upper surface of the front second frame member 41b and the outer surface of the downwardly inclined portion 65, extending to the left and right along the front edge of the battery unit 30.

[0110] In the vehicle's body structure, the torque box 70 is housed at the step 68, allowing the front end of the battery unit 30 and the torque box 70 to be arranged in a vertically overlapping manner. This allows the battery unit 30 to be formed into a rectangle approximately the same size as the rectangular floor panel 8 when viewed from above. This ensures the functionality of the torque box 70 and allows the battery unit 30 to be expanded forward, enabling a large-capacity battery unit 30.

[0111] <Torque chamber and main body structure components associated with the torque chamber>

[0112] When a load is applied to the vehicle from the front due to a collision or other reasons, the bumper beam 2 bears the load. Most of the load borne by the bumper beam 2 is transmitted to the rear via the left and right energy-absorbing boxes 12, 12 and a pair of front side brackets 5, 5.

[0113] The torque box 70 connects the rear ends 5b of the left and right front side frames 5, 5 to the front ends of the side beams 6. Thus, the torque box 70 transmits the loads acting on the pair of front side frames 5, 5 to the pair of side beams 6, 6.

[0114] The torque box 70 needs to meet specified strength and rigidity requirements in order to properly transmit loads. In this vehicle body 1, a torque box 70 with a closed cross-section structure and excellent strength and rigidity is formed by mounting a box panel 71 of a specific shape on the lower surface of the front end portion of the floor panel 8. Furthermore, the torque box 70 cooperates with the floor panel 8 to connect the rear end 5b of each of the left and right front side frames 5 to the front end of the side beam 6.

[0115] There are two box panels 71 on the vehicle body 1. They are formed in a left-right symmetrical shape. The left and right box panels 71 are respectively engaged with the left and right lower surfaces of the front end portion of the floor panel 8.

[0116] Figure 8 The example is shown in box panel 71 on the left. Figure 9 This is a perspective view showing the box panel 71 installed on the vehicle body 1. Figure 9 With the floor panel 8 removed, the box panel 71 is viewed from a right-rear angle. In the figure, multiple crosses indicate joint areas. Furthermore, the joints are generally made by spot welding, but the crosses do not indicate their location or number.

[0117] The box panel 71 is made of stamped steel sheet. The box panel 71 has: a front wall portion 71a facing forward, a rear wall portion 71b facing rearward, a lower wall portion 71c facing downward, and a pair of side wall portions 71d, 71d facing to the side (the side wall portion facing the outer side in the vehicle width direction is called the outer side wall portion 71d, and the side wall portion facing the inner side in the vehicle width direction is called the inner side wall portion 71d).

[0118] The rear wall portion 71b has a first flange portion 71e extending along its upper edge. The outer wall portion 71d has: a second flange portion 71f extending along its rear edge, a third flange portion 71g extending from its lower end along the lower wall portion 71c and the rear wall portion 71b, and a fourth flange portion 71h extending from the lower end of the second flange portion 71f along the third flange portion 71g.

[0119] The inner wall portion 71d is formed in a manner that coincides with the side surface shape of the bulge portion 8b of the floor panel 8. For example... Figure 4 , Figure 6As shown, the inner wall portion 71d and the side surface of the bulge portion 8b are joined together in an overlapping state.

[0120] The lower wall portion 71c is formed as a strip opposite to the upper surface of the front side second frame member 41b of the battery cell 30. For example... Figure 3 , Figure 6 As shown, the lower wall portion 71c is configured to extend outward in the vehicle width direction from the forming portion of the bulge 8b in the front end portion of the floor panel 8 in a generally horizontal state. A fastening base 72 for bolt fastening is provided in the lower wall portion 71c.

[0121] The front wall portion 71a and the rear wall portion 71b slope upwards from the long side portion of the lower wall portion 71c. The slope of the front wall portion 71a is formed in coordination with the slope of the upwardly sloped surface 8a in the front end portion of the floor panel 8. Figure 3 , Figure 4 As shown, the front wall portion 71a and the upwardly inclined surface portion 8a are joined in an overlapping state.

[0122] The inclination of the rear wall portion 71b is formed in conjunction with the inclination of the downwardly inclined portion 65 in the front end portion of the battery cell 30. For example... Figure 3 As shown, the first flange portion 71e of the rear wall portion 71b is engaged with the lower surface of the floor panel 8 in an overlapping state.

[0123] The outer wall portion 71d is formed into a triangular shape that slopes upward from the inclined outer edge of the front wall portion 71a. For example... Figure 4 , Figure 5 , Figure 9 As shown, the outer end of the torque box 70 in the vehicle width direction is joined to the front end of the side beam 6 from multiple directions via the edge of the outer side wall portion 71d and the second flange portion 71f to the fourth flange portion 71h.

[0124] In detail, such as Figure 9 As shown, the edge of the outer wall portion 71d and the third flange portion 71g are joined to the inner surface 6a of the side beam 6. Figure 5 As shown, the second flange 71f engages with the front end face 6b of the side beam 6. The fourth flange 71h engages with the lower surface 6c of the side beam 6. Thus, the torque box 70 is securely connected to the front end of the side beam 6.

[0125] Each torque box 70 extends relatively long in the left-right direction at the front end of the floor panel 8 and has a closed cross-section structure with a roughly triangular cross-section that has a small deviation in aspect ratio when viewed from the left-right direction. Therefore, these torque boxes 70 have excellent strength and rigidity.

[0126] As described above, each front side frame 5 engages with the upwardly inclined surface 8a of the floor panel 8 and the torque box 70 via its rear end 5b. Specifically, as... Figure 3 , Figure 4 , Figure 5 As shown, the rear end 5b of each front side frame 5 has a frame engagement portion formed in accordance with the shape of the upwardly inclined face 8a and the front wall portion 71a of the torque box 70.

[0127] Furthermore, the frame joint is provided with a joint flange 5d that contacts the upwardly inclined surface 8a and the front wall portion 71a. By engaging the joint flange 5d with the front surfaces of the upwardly inclined surface 8a and the front wall portion 71a, each front side frame 5 is connected to the floor panel 8 and the torque box 70.

[0128] That is, each torque box 70, with its closed cross-section structure possessing excellent strength and rigidity, works in conjunction with the floor panel 8 to connect the rear end 5b of each of the left and right front side frames 5 to the front end of the side beam 6. Therefore, when a load acts on each front side frame 5 from the front, the load can be effectively transferred to each torque box 70. Furthermore, the load acting on each torque box 70 can be effectively transferred to each side beam 6, thus fully utilizing the function of the torque box 70.

[0129] like Figure 7B As shown, a stepped portion 68 is provided at the front end of the battery cell 30. Furthermore, as... Figure 3 As shown, the stepped portion 68 is formed along the lower wall portion 71c and the rear wall portion 71b of each torque box 70. Thus, the front end portion of the battery unit 30 and each torque box 70 are arranged vertically overlapping with a very small gap C. Consequently, the battery unit 30, when viewed from above, is a rectangle approximately the same size as the floor panel 8. As a result, the battery unit 30 is supported by a pair of torque boxes 70, 70 with excellent strength and rigidity, and a pair of side beams 6, 6.

[0130] Specifically, such as Figure 3 , Figure 6 As shown, a bolt support tube 31a is installed on the front fastening part 31, extending vertically through the front second frame member 41b. The upper end of the bolt support tube 31a protrudes from the upper surface of the front second frame member 41b. Bolts 31b inserted into the bolt support tube 31a are fastened to the fastening base 72 of the lower wall portion 71c of each torque box 70.

[0131] Although not shown, the fastening portions 32 on each side of the support portion 42 provided on the first frame member 41a are also constructed in the same manner as the front fastening portion 31. That is, the bolts of the bolt support tubes inserted into the fastening portions 32 on each side are fastened and fixed to the side beams 6. As a result, the lower surface of the floor panel 8 containing the torque box 70 is opposite to the upper surface of the battery housing 30b containing the frame member 41 and the cover member 60 with a predetermined gap (gap C).

[0132] The stepped portion 68 of the battery cell 30 is formed along the lower wall portion 71c and the rear wall portion 71b of the torque box 70. Therefore, the capacity of the battery casing 30b can be maximized. The battery casing 30b is made of aluminum, while the floor panel 8 and the torque box 70 are made of steel. Due to the difference in thermal expansion coefficients of the materials, if the battery casing 30b is brought into close contact with the floor panel 8, etc., they may become skewed or deformed.

[0133] To address this, a predetermined gap C is provided between them to prevent such defects. Furthermore, the battery cell 30 generates heat during use. The battery cell 30 can also become very hot. By providing a gap C between the floor panel 8 and the battery casing 30b, a large surface area for heat dissipation can be ensured above the battery cell 30.

[0134] Thus, the front body structure of a vehicle using the technology disclosed herein can ensure the function of the torque box and can expand the battery cells forward to increase their capacity.

[0135] Furthermore, the technology disclosed herein is not limited to the embodiments described above, but also includes various other structures. For example, in this embodiment, an electric vehicle is exemplified as a vehicle, but the vehicle could also be a hybrid vehicle. The shape of the body structure including the box panel 71 and the detailed portions of the battery cell 30 can be appropriately modified according to specifications, as long as it does not affect the application of the technology disclosed herein.

Claims

1. A front body structure of a vehicle, equipped with a battery unit, characterized in that, have: Floor panel, which forms the floor of the vehicle's cabin; A pair of side beams that extend along the left and right sides of the floor panel in the front-back direction; A pair of front side frames, which extend forward separately from the left and right sides of the front side of the floor panel; as well as A torque box having a closed cross-section structure formed by mounting a box panel on the lower surface of the front end portion of the floor panel, and the torque box cooperating with the floor panel to connect the rear ends of the left and right front side frames to the front ends of the side beams. The battery cell has a rectangular appearance when viewed from above and is arranged below the floor panel in a manner that extends along the floor panel. By providing a step portion at the front end of the battery cell that is lower than the upper surface of the battery cell, and housing the torque box in the step portion, the front end of the battery cell and the torque box are configured to overlap vertically.

2. The front body structure of the vehicle according to claim 1, characterized in that, The torque box has: a front wall facing forward, a rear wall facing backward, and a lower wall facing downward. The stepped portion is formed along the lower wall portion and the rear wall portion.

3. The front body structure of the vehicle according to claim 2, characterized in that, The torque box also has a side wall portion facing to the side. The torque box engages with the front end of the side beam from multiple directions.

4. The front body structure of the vehicle according to claim 2 or 3, characterized in that, Both sides of the rear end portion of the front side frame are engaged with the torque box via the front wall portion.

5. The front body structure of the vehicle according to claim 2, characterized in that, The battery unit has a battery casing that houses individual battery cells. The battery casing has: a rectangular frame member; and a bottom member and a cover member, which are mounted on the frame member and cover the top and bottom of the battery cell. The stepped portion is formed by the frame member opposite to the lower wall portion and the cover member opposite to the rear wall portion. The frame component is fixed to the lower wall portion.

6. The front body structure of the vehicle according to claim 5, characterized in that, The lower surface of the floor panel containing the torque box is opposite the upper surface of the battery housing containing the frame member and the cover member, separated by a predetermined gap.

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