Lower structure of an electric vehicle

Abstract

A lower structure of an electric vehicle that takes into account both an increase in battery capacity and protection of the battery during a side collision without causing an increase in weight or cost. The electric vehicle (1) comprises: a battery unit (4) arranged below a floor panel (61) and between a tunnel side frame (63) and a floor side frame (66); and a mounting bracket (8) connecting the battery unit to the tunnel side frame and the floor side frame. The mounting bracket comprises: a lower wall portion (80) supporting the bottom of the battery unit; an outer longitudinal wall portion (81) extending upward from the outer end of the lower wall portion and connected to the floor side frame; and an inner longitudinal wall portion (82) extending upward from the inner end of the lower wall portion and connected to the tunnel side frame. The connection position of the inner longitudinal wall portion to the tunnel side frame is located above the vehicle compared to the connection position of the outer longitudinal wall portion to the floor side frame.

Description

Technical Field

[0001] The technology disclosed herein relates to a lower structure of an electric vehicle. Background Art

[0002] For example, Patent Document 1 discloses a battery mounting structure for a vehicle. Specifically, Patent Document 1 discloses a vehicle comprising: a mounting bracket that supports a battery from below; tunnel-side frames disposed at the left and right ends of a floor tunnel (tunnel portion); and floor-side frames (floor frames) disposed below the floor panel and on the vehicle's outer sides relative to the tunnel-side frames.

[0003] Furthermore, the mounting bracket disclosed in Patent Document 1 is formed to span from the tunnel-side frame to the floor-side frame, and the battery can be disposed below the floor panel by connecting the battery to the tunnel-side frame and the floor-side frame.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2017-77840

[0007] Technical problem to be solved by the invention

[0008] When using the vehicle disclosed in Patent Document 1, the floor-side frame is positioned on the vehicle's outer side, closer to the rocker. This widens the gap between the tunnel-side frame and the floor-side frame. This widens the gap between the tunnel-side frame and the floor-side frame, contributing to a larger battery and, in turn, to increased battery capacity.

[0009] However, when the battery capacity is increased as described above, the side surfaces of the battery (particularly the side surfaces facing the vehicle outer side) also come close to the rocker. If the side surfaces of the battery are close to the rocker, it will be disadvantageous in side collision.

[0010] As a precaution against side collisions, hollow energy-absorbing members can be installed on the sides of the battery, for example. However, installing new energy-absorbing members is not suitable because it increases weight and costs. Summary of the Invention

[0011] The technology disclosed herein has been developed in view of this point, and its purpose is to achieve both improvement in battery capacity and protection of the battery during a side collision without causing an increase in weight or cost.

[0012] Technical means for solving technical problems

[0013] A first embodiment of the present invention relates to a lower structure of an electric vehicle. The electric vehicle comprises: a floor panel having a floor tunnel extending in the vehicle front-rear direction; tunnel side frames disposed below the floor panel and on both sides of the floor tunnel in the vehicle width direction; floor side frames disposed below the floor panel and outward in the vehicle width direction relative to the tunnel side frames; a battery unit disposed below the floor panel and between the tunnel side frames and the floor side frames in the vehicle width direction; and a mounting bracket formed to span from the tunnel side frames to the floor side frames in the vehicle width direction and connect the battery unit to the tunnel side frames and the floor side frames.

[0014] Moreover, according to the first embodiment, the mounting bracket includes: a lower wall portion that supports the bottom of the battery unit; an outer longitudinal wall portion that extends upward from an end portion of the lower wall portion on the vehicle outer side and is connected to the floor side frame; and an inner longitudinal wall portion that extends upward from an end portion of the lower wall portion on the vehicle inner side and is connected to the tunnel side frame, and a connection position of the inner longitudinal wall portion to the tunnel side frame is located above the vehicle compared to a connection position of the outer longitudinal wall portion to the floor side frame.

[0015] Here, the inner vertical wall portion and the tunnel side frame may be directly connected by fasteners such as bolts, or may be indirectly connected via a tunnel cross member, etc. The same applies to the outer vertical wall portion and the floor side frame.

[0016] Furthermore, the electric vehicle includes a floor cross member disposed on the floor panel and arranged to span both sides of the floor panel in the vehicle width direction, and a fragile portion is formed on the vehicle lower side of the floor cross member, the fragile portion being configured to promote bending of the floor cross member toward the vehicle upper side when a load is input from the vehicle side.

[0017] According to the first embodiment, the connection point between the outer longitudinal wall portion and the floor side frame is located below the vehicle, compared to the connection point between the inner longitudinal wall portion and the tunnel side frame. In this case, when a load is input from the side of the vehicle, the connection point between the outer longitudinal wall portion and the floor side frame can be set below the position where the load is input. Therefore, when a load is input from the side of the vehicle, the outer longitudinal wall portion involved in the first embodiment is more likely to bear a load toward the lower side of the vehicle than the inner longitudinal wall portion. By utilizing this load, the outer longitudinal wall portion is displaced toward the lower side of the vehicle, thereby allowing the mounting bracket to swing like a swing with the connection point between the inner longitudinal wall portion and the tunnel side frame as the fulcrum. By swinging the mounting bracket, the battery unit supported by the lower wall portion can also swing toward the lower side of the vehicle. This swinging causes the battery unit to retreat toward the lower side of the vehicle, thereby effectively protecting the battery unit.

[0018] Even when the floor side frame is arranged on the outside of the vehicle and close to the rocker, the battery unit can be well protected. In this regard, the first method can achieve both increased battery capacity and battery protection during side collisions without increasing weight or cost.

[0019] Furthermore, the floor cross member can be made to protrude upward when a load is applied from the side of the vehicle. By using the mounting bracket to swing the battery unit downward and protrude the floor cross member upward, interference between the floor cross member and the battery unit can be minimized, effectively protecting the battery unit.

[0020] According to the second aspect of the present invention, the width of the inner vertical wall portion in the vehicle front-rear direction may be shorter than the width of the outer vertical wall portion in the vehicle front-rear direction.

[0021] According to the second aspect, by shortening the width of the inner vertical wall, the mounting bracket can be more easily swung about the connection point between the inner vertical wall and the tunnel-side frame, which is useful for protecting the battery.

[0022] In addition, according to a third embodiment of the present invention, the inner longitudinal wall portion may include: a first inner longitudinal wall portion, which is connected to the tunnel side frame; and a second inner longitudinal wall portion, which is arranged to be aligned with the first inner longitudinal wall portion in the vehicle front-rear direction and is connected to the tunnel side frame, and the total width of the first inner longitudinal wall portion in the vehicle front-rear direction and the width of the second inner longitudinal wall portion in the vehicle front-rear direction is shorter than the width of the outer longitudinal wall portion in the vehicle front-rear direction.

[0023] According to the third aspect, the inner longitudinal wall portion is formed of the first inner longitudinal wall portion and the second inner longitudinal wall portion. This allows the mounting bracket to be connected to the tunnel-side frame at at least two locations spaced apart in the front-to-rear direction. This stabilizes the connection between the inner longitudinal wall portion and the tunnel-side frame. Furthermore, according to the third aspect, a gap is provided between the first inner longitudinal wall portion and the second inner longitudinal wall portion. This facilitates shortening the overall width of the inner longitudinal wall portion, which also facilitates the swinging motion of the mounting bracket.

[0024] In addition, according to a fourth aspect of the present invention, the tunnel side frame may include: a first longitudinal wall portion that faces the vehicle inner side of the floor tunnel and is inclined toward the vehicle inner side as it moves toward the vehicle upper side; and a second longitudinal wall portion that faces the vehicle outer side of the floor tunnel and is inclined toward the vehicle outer side as it moves toward the vehicle upper side, the second longitudinal wall portion being provided in a manner opposing to a corner portion on the vehicle inner side of an upper end portion of the battery unit in the vehicle width direction and being formed to be more steeply inclined with respect to the vehicle up-down direction than the first longitudinal wall portion.

[0025] As the mounting bracket swings, the corners of the battery cells on the vehicle's inner side may come into contact with the second vertical wall. Therefore, by making the second vertical wall relatively steeply inclined as in the fourth embodiment, the corners that come into contact with the second vertical wall can be smoothly guided downward in the vehicle, compared to, for example, a configuration in which the second vertical wall extends parallel to the vehicle's vertical direction. This advantageously protects the battery cells.

[0026] In addition, according to the sixth embodiment of the present invention, the fragile portion may be arranged on the outside of the vehicle compared to the tunnel side frame in the vehicle width direction, and the corner on the outside of the vehicle in the upper end portion of the battery unit is cut off, thereby forming a vacant space between the upper end portion of the battery unit and the lower surface of the floor panel, and piping components extending in the front-rear direction of the vehicle are arranged on the outside of the vehicle in the vacant space.

[0027] According to the sixth aspect, by swinging the battery unit toward the bottom of the vehicle and protruding the floor cross member toward the top of the vehicle, the provision of the aforementioned free space effectively reduces interference between piping components and the top surface of the battery unit, as well as interference between the piping components and the floor cross member. Furthermore, by cutting out the corners of the battery unit to provide the free space, piping components can be easily guided toward the top of the vehicle when the top surface around the corners contacts the piping components.

[0028] Effects of the Invention

[0029] As described above, according to the present invention, it is possible to achieve both an increase in battery capacity and protection of the battery during a side collision without causing an increase in weight or cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a bottom view illustrating the lower structure of the electric vehicle.

[0031] Figure 2 It is a bottom view illustrating the lower structure around the battery cell.

[0032] Figure 3 It is a perspective view illustrating the lower structure around the battery cell.

[0033] Figure 4 yes Figure 2 AA cross-sectional view.

[0034] Figure 5 yes Figure 2 BB cross-sectional view.

[0035] Figure 6 This is a perspective view illustrating a battery unit and a mounting bracket as viewed from the inside of a vehicle.

[0036] Figure 7 This is a perspective view illustrating a battery unit and a mounting bracket as viewed from the outside of a vehicle.

[0037] Figure 8 This is a diagram illustrating the structure around a floor beam.

[0038] Figure 9 This is a diagram illustrating the transition of the swing of the battery unit during a side collision of an electric vehicle.

[0039] Figure 10 It is a diagram for explaining the width of the mounting bracket.

[0040] Figure 11 It is a diagram showing a modified example of the mounting bracket.

[0041] Explanation of symbols

[0042] 1 Electric Vehicles

[0043] 61 Floor panels

[0044] 62 floor passage

[0045] 63 channel side frame

[0046] 63a first vertical wall portion

[0047] 63b Second vertical wall portion

[0048] 66 floor side frame

[0049] 67 floor beams

[0050] 673 First Fragile Section (Fragile Section)

[0051] 674 Second fragile part (fragile part)

[0052] 4 battery cells

[0053] 8Mounting bracket

[0054] 80 lower wall

[0055] 81 outer longitudinal wall

[0056] 82 inner longitudinal wall

[0057] 82a first inner vertical wall portion

[0058] 82b second inner vertical wall portion

[0059] 86 Free Space

[0060] 91 Piping components

[0061] Wo outer width

[0062] Wi inner width DETAILED DESCRIPTION

[0063] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0064] Figure 1 It is a bottom view illustrating the lower structure of the electric vehicle 1 according to the present invention. Figure 2 4 is a bottom view illustrating the lower structure around the battery unit 4. Figure 3 4 is a perspective view illustrating the lower structure around the battery unit 4. Figure 2 It is an enlarged representation Figure 1 FIG. 4 is a diagram showing the arrangement position of the battery unit 4, Figure 3 This is a perspective view of the lower structure of the electric vehicle 1 when viewed from the rear and obliquely above with the floor panel 61 removed. Figure 4 yes Figure 2 AA cross-sectional view, Figure 5 yes Figure 2 BB cross-sectional view. In detail, Figure 4 is a cross section passing through the first outer fastener 831 and the first inner fastener 841 described later, Figure 5 This is a cross section passing through a second outer fastening member 832 and a second inner fastening member 842 to be described later.

[0065] In the following description, the terms "front," "rear," "up," and "down" are defined with reference to the electric vehicle 1. Specifically, in the following description, "front" refers to the front in the vehicle's longitudinal direction, which is the longitudinal direction of the electric vehicle 1, and "rear" refers to the rear in the vehicle's longitudinal direction. Similarly, "up" refers to the vehicle's height, which is the height of the electric vehicle 1, and "down" refers to the vehicle's height. In the following description, the vehicle's longitudinal direction may be referred to simply as the "front-rear direction," and the "vehicle's height direction" may be referred to as the "up-down direction."

[0066] Furthermore, the upper side (upper side) in the vehicle height direction is sometimes referred to as the "upper side of the vehicle (upper side of the vehicle)" or simply as the "upper side (upper side)", the lower side (lower side) in the vehicle height direction is sometimes referred to as the "lower side of the vehicle (lower side of the vehicle)" or simply as the "lower side (lower side)", the front side (front side) in the vehicle front-to-rear direction is sometimes referred to as the "vehicle front (vehicle front side)" or simply as the "front (front side)", and the rear side (rear side) in the vehicle front-to-rear direction is sometimes referred to as the "vehicle rear (vehicle rear side)" or simply as the "rear (rear side)".

[0067] In the following description, the terms "left" and "right" are also defined with reference to the electric vehicle 1. Specifically, in the following description, "left" refers to the left side in the vehicle width direction when viewing the electric vehicle 1 from the rear toward the front, and "right" refers to the right side when viewing the vehicle from the rear toward the front. The vehicle width direction is sometimes referred to as the "left-right direction."

[0068] Furthermore, in some cases, a direction along the vehicle width direction away from the center of the electric vehicle 1 (specifically, the center of the floor tunnel 62 in the vehicle width direction) is referred to as the "vehicle outside (vehicle outer side)" or simply as the "outer side (outer side)", and a direction approaching the center of the electric vehicle 1 (the center of the floor tunnel 62 in the vehicle width direction) is referred to as the "vehicle inside (vehicle inside)" or simply as the "inner side (inner side)".

[0069] (Overall structure)

[0070] Figure 1 The electric vehicle 1 illustrated in FIG includes elements related to the body of the electric vehicle 1 such as a floor panel 61 and a floor tunnel 62 , and elements related to the power of the electric vehicle 1 such as an electric drive system 3 and a battery unit 4 .

[0071] <Elements related to the vehicle body>

[0072] First, the electric vehicle 1 includes, as vehicle body-related elements, a floor panel 61 , a floor tunnel 62 , tunnel side frames 63 , rocker sills 64 , tunnel cross-members 651 and 652 , floor side frames 66 , and a floor cross-member 67 .

[0073] A floor panel 61 is provided at the bottom of the electric vehicle 1. The floor panel 61 forms the floor of the vehicle interior of the electric vehicle 1. The floor panel 61 extends in the front-rear direction and the vehicle width direction, connecting two rocker sills 64 provided on both sides of the electric vehicle 1 in the vehicle width direction.

[0074] A floor tunnel 62 extending in the vehicle front-rear direction is provided on the floor panel 61. The floor tunnel 62 is provided in a central portion of the floor panel 61 in the vehicle width direction.

[0075] Specifically, the floor tunnel 62 of this embodiment constitutes a space for accommodating the exhaust pipe 12 and the propeller shaft 52. Figure 4 or Figure 5 As shown, it rises upwards toward the floor panel 61 and Figure 1 Extends in the front-to-rear direction as shown.

[0076] A pair of left and right tunnel side frames 63 are arranged on both sides of the floor tunnel 62 in the vehicle width direction. The tunnel side frames 63 are arranged below the floor panel 61. The tunnel side frames 63 are highly rigid frames that extend in the front-rear direction along the floor tunnel 62. Figure 4 or Figure 5 As shown, the tunnel side frames 63 are formed in a substantially hat-shaped cross section with their openings facing upward, and are joined to the lower surfaces of both side portions of the floor tunnel 62 in the vehicle width direction.

[0077] In detail, Figure 4 As shown, the tunnel side frame 63 according to this embodiment includes a first vertical wall portion 63a and a second vertical wall portion 63b. As described below, a first tunnel cross member 651 and a mounting bracket 8 can be connected to the lower wall portion of the tunnel side frame 63 that connects the first vertical wall portion 63a and the second vertical wall portion 63b.

[0078] The first vertical wall portion 63a faces the vehicle interior of the floor tunnel 62. The first vertical wall portion 63a is inclined toward the vehicle interior as it approaches the vehicle upper side. Meanwhile, the second vertical wall portion 63b faces the vehicle exterior of the floor tunnel 62. The second vertical wall portion 63b is inclined toward the vehicle exterior as it approaches the vehicle upper side.

[0079] Here, the second vertical wall portion 63b is formed to be more steeply inclined relative to the vehicle vertical direction than the first vertical wall portion 63a. Specifically, let the first inclination angle θ1 be the more acute angle of the inclination formed between the vehicle height direction and the inclination direction of the first vertical wall portion 63a, and let the second inclination angle θ2 be the more acute angle of the inclination formed between the vehicle height direction and the inclination direction of the second vertical wall portion 63b. The second inclination angle θ2 is set to be greater than the first inclination angle θ1 (θ2 > θ1). In other words, the substantially hat-shaped cross-section of the tunnel side frame 63 is bilaterally asymmetrical.

[0080] Tunnel cross members 651 and 652 are installed at predetermined locations in the floor tunnel 62, more specifically, at two locations in the rear portion of the floor tunnel 62. The first tunnel cross member 651 on the front side of the two tunnel cross members 651 and 652 is connected to the tunnel side frames 63, and connects the two tunnel side frames 63 to each other (at Figure 4 The first tunnel cross member 651 is located rearward of the transmission support member 21 described later.

[0081] The rear second tunnel cross member 652 of the two tunnel cross members 651 and 652 also extends in the vehicle width direction to connect the two tunnel side frames 63. The width of the first tunnel cross member 651 in the front-rear direction is wider than that of the second tunnel cross member 652 in the front-rear direction.

[0082] The floor side frames 66 are positioned below the floor panel 61 in the vehicle, outboard of the tunnel side frames 63 in the vehicle width direction. They are also positioned inboard of the rocker 64 in the vehicle width direction. Therefore, the floor side frames 66 are positioned between the rocker 64 and the tunnel side frames 63.

[0083] The floor side frame 66 is a high rigidity frame. Figure 4 or Figure 5 As shown, the floor side frames 66 are formed in a substantially hat-shaped cross section with their openings facing upward, and are joined to the lower surfaces of both side portions of the floor panel 61 in the vehicle width direction.

[0084] At the front end of the floor panel 61, the floor side frame 66 is located near the middle of the rocker 64 and the tunnel side frame 63 in the vehicle width direction. The floor side frame 66 tilts outward in the vehicle width direction as it moves toward the rear of the electric vehicle 1, and contacts the inner side of the rocker 64 near the center of the floor panel 61 in the front-to-back direction. The floor side frame 66, which contacts the inner side of the rocker 64, extends straight toward the rear of the electric vehicle 1 along the inner side of the rocker 64. Figure 4 and Figure 5As illustrated, the floor side frames 66 , which are in contact with the inner sides of the rocker 64 , are closer to the rocker 64 than to the tunnel side frames 63 in the vehicle width direction.

[0085] In addition, Figure 4 In the figures, only the floor side frame 66 on the left side of the floor tunnel 62 is shown, but a floor side frame 66 is also provided on the right side of the floor tunnel 62. The two floor side frames 66 are provided so as to be bilaterally symmetrical.

[0086] The floor cross member 67 is disposed on the floor panel 61. The floor cross member 67 is also disposed so as to span both sides of the floor panel 61 in the vehicle width direction with the floor tunnel 62 interposed therebetween.

[0087] Specifically, the floor cross member 67 of this embodiment extends in the vehicle width direction, connecting the rocker 64 provided on the left side of the electric vehicle 1 and the rocker 64 provided on the right side of the electric vehicle 1, with the floor tunnel 62 interposed therebetween. The floor cross member 67 forms a closed cross section extending in the vehicle width direction and is capable of supporting the left and right seats arranged on the front side of the vehicle cabin.

[0088] Here, if Figure 8 As shown, the floor cross member 67 includes a hollow first member 671 extending in the vehicle width direction and second members 672 provided at the left and right ends (the left end in the example) of the first member 671. The second member 672 is arranged directly above the floor side frame 66 along the vehicle height direction.

[0089] Furthermore, two fragile portions 673 and 674 are formed on the vehicle's lower side of the floor cross member 67. These fragile portions 673 and 674 are configured to promote bending of the floor cross member 67 toward the vehicle's upper side when a load is input from the side of the electric vehicle 1 (outside the electric vehicle 1). Both fragile portions 673 and 674 are located closer to the floor side frames 66 than to the tunnel side frames 63 in the vehicle width direction.

[0090] In detail, Figure 8 As illustrated, of the two fragile portions 673 and 674, the first fragile portion 673 formed in the first member 671 is located near the corner 4b on the floor side frame 66 side (the corner on the vehicle outer side) of the battery unit 4. Of the two fragile portions 673 and 674, the second fragile portion 674 formed in the second member 672 is located near the floor side frame 66, which is located on the vehicle outer side relative to the battery unit 4.

[0091] Both the first fragile portion 673 and the second fragile portion 674 are formed to promote deformation of the lower vehicle side of the floor cross member 67 more than the upper vehicle side. With this fragile portion formation, when a load is applied from the side of the electric vehicle 1, the lower vehicle side of the floor cross member 67 (particularly the portion where the first fragile portion 673 and the second fragile portion 674 are provided) deforms so that they approach each other in the vehicle width direction. This deformation is equivalent to causing the first fragile portion 673 and the second fragile portion 674 to collapse in the vehicle width direction. By inducing this deformation, not only does a bend originating from the first fragile portion 673 or the second fragile portion 674 occur, but this bend can also be caused to protrude toward the upper vehicle side.

[0092] Specifically, the first fragile portion 673 is formed by a notch provided in the lower half of the first component 671 of the floor cross member 67. The notch facilitates deformation that causes the lower half of the first component 671 to collapse. Meanwhile, the second fragile portion 674 is formed by a weld bead provided in the lower half of the second component 672 of the floor cross member 67. The weld bead facilitates deformation that causes the lower half of the second component 672 to collapse.

[0093] <Power-related factors>

[0094] Next, as power-related elements, electric vehicle 1 includes an engine (not shown), a transmission 2, and an electric drive system 3 as elements related to the power transmission system. Electric vehicle 1 is a four-wheel drive vehicle based on a front-engine, rear-wheel drive vehicle. Electric vehicle 1 also includes a transfer case 51 and a propeller shaft 52 as elements related to the power transmission system.

[0095] The engine is a gasoline engine supplied with fuel containing at least gasoline, or a diesel engine supplied with diesel fuel. The engine is either a spark-ignition type or a compression-ignition type. The engine type is not particularly limited. The engine is installed in a so-called longitudinal arrangement within an engine compartment located at the front of electric vehicle 1. A fuel tank 11 is provided at the rear of electric vehicle 1. Fuel tank 11 stores fuel for the engine.

[0096] An exhaust pipe 12 for discharging exhaust gas is connected to the engine. Exhaust pipe 12 is located on the underside of floor panel 61, which forms the floor of the interior of electric vehicle 1. Exhaust pipe 12 extends from the engine compartment toward the rear of electric vehicle 1. More specifically, on the right side of floor tunnel 62, exhaust pipe 12 extends from the engine compartment toward the rear of electric vehicle 1, then bends toward the center in the vehicle width direction, extending further toward the rear of electric vehicle 1 along floor tunnel 62. A catalytic converter 13 is also located midway along exhaust pipe 12.

[0097] The electric drive system 3 includes an electric motor 30, an inverter (not shown), and a battery unit 4. The electric motor 30 is mounted on the engine's output shaft and is interposed between the engine and the transmission 2. During power operation, the electric motor 30 outputs driving torque for vehicle propulsion and also regenerates braking force for the vehicle.

[0098] The transmission 2 is, for example, an automatic transmission including at least one planetary gear mechanism. However, the transmission 2 is not limited to an automatic transmission. The transmission 2 is coupled to the output shafts of the engine and the motor 30. The transmission 2 changes the speed of the torque of the engine and / or the motor 30 and outputs the torque.

[0099] The transmission 2 is arranged on the rear side of the motor 30. Figure 1 and Figure 2 As shown, the electric motor 30 and the transmission 2 are disposed inside the floor tunnel 62. The housing of the transmission 2 extends in the front-rear direction along the floor tunnel 62 at the front portion of the floor tunnel 62.

[0100] The transfer case 51 is connected to the output shaft of the transmission 2. The transfer case 51 is disposed within the floor tunnel 62. The housing of the transfer case 51 is integrated with the housing of the transmission 2. Hereinafter, the integrated housing of the transfer case 51 and the housing of the transmission 2 are collectively referred to as the "housing of the transmission 2."

[0101] The rear end portion of the transmission 2 housing, more precisely, the housing of the transfer case 51, is supported by the transmission support 21. The transmission support 21 extends in the vehicle width direction so as to be spanned between the two tunnel side frames 63.

[0102] The transmission shaft 52 is connected to the transfer case 51. The transfer case 51 distributes the torque of the engine and / or the electric motor 30 to the front wheels and the rear wheels.

[0103] The propeller shaft 52 extends from the transfer case 51 toward the rear of the vehicle inside the floor tunnel 62. The propeller shaft 52 is connected to a rear drive shaft via a rear differential gear (not shown), and the rear drive shaft is connected to the left and right rear wheels.

[0104] The battery unit 4 is electrically connected to the electric motor 30 via an inverter. The battery unit 4 supplies driving power to the electric motor 30 and is charged during regeneration of the electric motor 30. The inverter supplies power from the battery unit 4 to the electric motor 30 during power operation and transmits power generated by the electric motor 30 to the battery unit 4 during regeneration.

[0105] like Figure 1 or Figure 2 As shown in the example, the battery unit 4 has a substantially rectangular shape when viewed from below. The battery unit 4 includes a battery assembly 41 and a junction box 42. Figure 6 or Figure 7 As shown, the junction box 42 is disposed at the front end of the battery unit 4 , and the battery assembly 41 is disposed at the rear side of the junction box 42 .

[0106] The battery unit 4 is arranged below the vehicle floor panel 61. The battery unit 4 is also arranged between the tunnel side frame 63 and the floor side frame 66 in the vehicle width direction.

[0107] In detail, the battery unit 4 involved in this embodiment is arranged on the left side of the floor tunnel 62 on the lower side of the floor panel 61. More specifically, the battery unit 4 is arranged between the tunnel side frame 63 and the floor side frame 66 behind the transmission 2 and in front of the fuel tank 11. The battery unit 4 is arranged on the opposite side of the engine exhaust pipe 12 and the catalytic converter 13 across the floor tunnel 62. This arrangement structure can keep the electric drive system 3 away from heat sources. In addition, Figure 1 or Figure 2 Reference numeral 32 denotes a DC / DC converter 32 constituting a part of the electric drive system 3. The DC / DC converter 32 is disposed on the left side of the floor tunnel 62, on the left side of the transmission 2 and in front of the battery unit 4.

[0108] As described above, the floor side frames 66 are arranged to abut against the rocker 64 from the center to the rear of the floor panel 61 in the front-rear direction. Therefore, the distance between the tunnel side frames 63 and the floor side frames 66 in the vehicle width direction is wide at the rear of the floor panel 61. This wide space allows for the installation of the large battery unit 4. Consequently, the battery unit 4 has a relatively large capacity.

[0109] Furthermore, the electric vehicle 1 includes a mounting bracket 8 for connecting the battery unit 4 to the vehicle body. The battery unit 4 is mounted on the floor panel 61 via the mounting bracket 8 .

[0110] Hereinafter, the structure of the mounting bracket 8 will be described in detail with reference to the battery unit 4 .

[0111] (Structure of mounting bracket)

[0112] Figure 6 1 is a perspective view illustrating the battery unit 4 and the mounting bracket 8 as viewed from the inside of the vehicle. Figure 7 1 is a perspective view showing the battery unit 4 and the mounting bracket 8 as viewed from the outside of the vehicle. Figure 8 This is a diagram illustrating the structure of the floor cross member 67 . Figure 10 It is a diagram for explaining the width of the mounting bracket 8 .

[0113] like Figure 4 and Figure 5As shown, the mounting bracket 8 is formed to span from the tunnel-side frame 63 to the floor-side frame 66 in the vehicle width direction. The mounting bracket 8 can connect the battery unit 4 to the tunnel-side frame 63 and the floor-side frame 66. The battery unit 4 is mounted to the floor panel 61 via the tunnel-side frame 63 and the floor-side frame 66.

[0114] Specifically, the mounting bracket 8 according to this embodiment has a hat-shaped cross section with its opening facing upward. Figure 6 and Figure 7 As shown, the mounting bracket 8 includes a lower wall portion 80 , an outer vertical wall portion 81 , an inner vertical wall portion 82 , outer fasteners 831 , 832 , and inner fasteners 841 , 842 .

[0115] like Figure 6 or Figure 7 As shown, the lower wall portion 80 supports the bottom of the battery unit 4. Specifically, the lower wall portion 80 is formed into a rectangular plate extending in the vehicle longitudinal direction and the vehicle width direction. When viewed in a cross section along the vehicle width direction (a cross section perpendicular to the vehicle longitudinal direction), the lower wall portion 80 extends from near the tunnel-side frame 63 to near the floor-side frame 66. The lower wall portion 80 is located below the battery unit 4 and extends to cover the bottom surface of the battery unit 4. The lower wall portion 80 supports the battery unit 4 from the bottom.

[0116] Furthermore, a rectangular opening 85 is provided in the center of the lower wall 80. The opening 85 contributes to reducing the weight of the lower wall 80 and, in turn, the mounting bracket 8.

[0117] The outer longitudinal wall portion 81 extends upward from the vehicle outer end (the left end in the illustration) of the lower wall portion 80 and is connected to the floor side frame 66. Specifically, the outer longitudinal wall portion 81 is located outward (i.e., on the left) relative to the lower wall portion 80 in the vehicle width direction and is continuous with the left edge of the lower wall portion 80. On the left side of the battery unit 4, the outer longitudinal wall portion 81 expands in the front-to-rear direction and extends in the vertical direction.

[0118] The upper end of the outer longitudinal wall portion 81 is bent into a flange-like shape that protrudes outward in the vehicle width direction. A first outer fastener 831 is inserted into the front portion of this upper end, while a second outer fastener 832 is inserted into the rear portion of this upper end. The first outer fastener 831 and the second outer fastener 832 are inserted from below into the upper end of the outer longitudinal wall portion 81 and fastened to the floor side frame 66. This fastening connects the outer longitudinal wall portion 81 to the floor side frame 66.

[0119] The inner longitudinal wall portion 82 extends upward from the end portion of the lower wall portion 80 on the vehicle inner side (the right end portion in the figure) and is connected to the tunnel side frame 63. Specifically, the inner longitudinal wall portion 82 is located inward (i.e., on the right side) relative to the lower wall portion 80 in the vehicle width direction and is continuous with the right side edge of the lower wall portion 80. On the right side of the battery unit 4, the inner longitudinal wall portion 82 expands in the front-to-back direction and extends in the up-down direction. Figure 10 As illustrated, the width Wi of the inner vertical wall portion 82 in the vehicle longitudinal direction (hereinafter referred to as “inner width”) is shorter than the width Wo of the outer vertical wall portion 81 in the vehicle longitudinal direction (hereinafter referred to as “outer width”).

[0120] In more detail, the inner longitudinal wall portion 82 has a first inner longitudinal wall portion 82a and a second inner longitudinal wall portion 82b, wherein the first inner longitudinal wall portion 82a is connected to the channel side frame 63, and the second inner longitudinal wall portion 82b is arranged in the vehicle front-rear direction relative to the first inner longitudinal wall portion 82a and is connected to the channel side frame 63.

[0121] Here, if Figure 6 As shown in the example, the first inner longitudinal wall portion 82a and the second inner longitudinal wall portion 82b are formed as separate components and are arranged in the vehicle front-rear direction with a gap therebetween. Furthermore, the inner width Wi described above corresponds to the total width of the first inner longitudinal wall portion 82a in the vehicle front-rear direction (hereinafter referred to as the "first inner width") Wi1 and the second inner longitudinal wall portion 82b in the vehicle front-rear direction (hereinafter referred to as the "second inner width") Wi2 (i.e., Wi = Wi1 + Wi2).

[0122] Specifically, the first inner longitudinal wall portion 82a is positioned further forward of the vehicle than the second inner longitudinal wall portion 82b. The first inner longitudinal wall portion 82a is positioned inward (i.e., to the right) of the lower wall portion 80 in the vehicle width direction and is continuous with the front portion of the right edge of the lower wall portion 80. To the right of the battery unit 4, the first inner longitudinal wall portion 82a expands in the front-to-back direction and extends in the vertical direction.

[0123] In addition, the upper end portion of the first inner longitudinal wall portion 82a is bent into a flange shape protruding outward in the vehicle width direction, and a pair of front and rear first inner fasteners 841 are inserted into the upper end portion. Figure 4 As shown, the first inner fastener 841 fastens the upper end of the first inner longitudinal wall portion 82a to the first channel cross member 651 (see also FIG. Figure 3 As described above, the first tunnel cross member 651 is connected to the tunnel side frame 63. Therefore, through this joint fastening, the first inner side fastener 841 is connected to the tunnel side frame 63 via the first tunnel cross member 651.

[0124] Specifically, the upper end of the first inner longitudinal wall portion 82a is located closer to the center of the vehicle width than the tunnel-side frame 63. Consequently, the first inner longitudinal wall portion 82a is located at approximately the same position as the tunnel-side frame 63 in the vehicle width. Because the first inner longitudinal wall portion 82a is located closer to the center of the vehicle width, the right side of the battery unit 4 can be located closer to the center of the vehicle width, adjacent to the left side of the floor tunnel 62. This increases the size of the battery unit 4, and accordingly, its capacity.

[0125] In addition, if Figure 10 As shown, the mounting bracket 8 according to the present embodiment is configured such that a straight line L1 connecting the first outer fastener 831 and the first inner fastener 841 does not intersect with the opening 85 provided in the lower wall 80 .

[0126] On the other hand, the second inner longitudinal wall portion 82b is positioned further rearward of the vehicle than the first inner longitudinal wall portion 82a. The second inner longitudinal wall portion 82b is located inward (i.e., to the right) of the lower wall portion 80 in the vehicle width direction and is continuous with the rear portion of the right edge of the lower wall portion 80. To the right of the battery unit 4, the second inner longitudinal wall portion 82b expands in the front-to-back direction and extends in the vertical direction. The vehicle-height dimension of the second inner longitudinal wall portion 82b is slightly shorter than the vehicle-height dimension of the first inner longitudinal wall portion 82a.

[0127] In addition, the upper end portion of the second inner vertical wall portion 82b is bent into a flange shape protruding outward in the vehicle width direction, and the second inner fastener 842 is inserted into the upper end portion. Figure 5 As shown, the second inner fastener 842 fastens the upper end portion of the second inner vertical wall portion 82b and the tunnel-side frame 63 together. The second inner fastener 842 is connected to the tunnel-side frame 63 by this joint fastening.

[0128] In addition, if Figure 10 As shown, the mounting bracket 8 according to this embodiment is configured such that the straight line L2 connecting the second outer fastener 832 and the second inner fastener 842 does not intersect the opening 85 provided in the lower wall portion 80. Figure 10 As shown, the connection position between the second inner fastener 842 and the upper end of the second inner vertical wall portion 82b is arranged on the vehicle outer side relative to the connection position between the first inner fastener 841 and the upper end of the first inner vertical wall portion 82a.

[0129] Furthermore, in the present embodiment, the connection position between the inner vertical wall portion 82 and the tunnel side frame 63 is located above the vehicle relative to the connection position between the outer vertical wall portion 81 and the floor side frame 66 .

[0130] In other words, in this embodiment, the heights of the connection positions of the inner longitudinal wall portion 82 and the tunnel side frame 63 (hereinafter also referred to as "inner heights") Hi1, Hi2 are located above the vehicle compared to the height of the connection position of the outer longitudinal wall portion 81 and the floor side frame 66 (hereinafter also referred to as "outer height") Ho.

[0131] Specifically, in Figure 4 or Figure 5 In the illustrated example, heights based on the lower wall portion 80 (heights with the lower wall portion 80 as an origin) are exemplified as the outer height Ho and the inner heights Hi1 and Hi2 .

[0132] Among them, such as Figure 4 or Figure 5 As shown, the outside height Ho may be the height observed from a cross section through the first outside fastener 831 or a cross section through the second outside fastener 832. The outside heights Ho observed from the two cross sections are substantially the same, and therefore, are not distinguished from each other in the following description.

[0133] On the other hand, the inner heights Hi1 and Hi2 can be as follows Figure 4 The inside height Hi1 as viewed from a cross section through the first inside fastener 841 as shown, or as Figure 5 As shown in FIG. 1 , the inner height Hi2 observed from the cross section through the second inner fastening member 842 is slightly higher than the inner height Hi2 observed from the cross section through the second inner fastening member 842 and the second outer fastening member 832 (i.e., Hi1>Hi2).

[0134] Furthermore, both inner heights Hi1 and Hi2 are configured to be higher than the outer height Ho (i.e., Hi1>Ho and Hi2>Ho). That is, when viewed from a cross section passing through the first inner fastener 841 and the first outer fastener 831, as shown in FIG. Figure 4 As shown, the inner height Hi1 is higher than the outer height Ho. Similarly, when viewed from a cross section through the second inner fastener 842 and the second outer fastener 832, as shown in FIG. Figure 5 As shown, the inner height Hi2 is greater than the outer height Ho. As a result of this configuration, in this embodiment, the length of the inner vertical wall portion 82 in the vehicle height direction is greater than the length of the outer vertical wall portion 81 in the vehicle height direction. Specifically, both the first inner vertical wall portion 82a and the second inner vertical wall portion 82b extend further upward in the vehicle than the outer vertical wall portion 81.

[0135] The battery unit 4 according to the present embodiment is housed in a housing space defined by the mounting bracket 8 configured as described above, the second vertical wall portion 63 b of the tunnel-side frame 63 , the floor-side frame 66 , and the floor panel 61 .

[0136] At this time, if Figure 5 As shown, the second vertical wall portion 63b is disposed so as to oppose the vehicle-inside corner portion 4a of the upper end portion of the battery unit 4 in the vehicle width direction. The vehicle-inside corner portion 4a is positioned higher than the connection point between the second inner vertical wall portion 82b and the tunnel-side frame 63, which is the connection point between the inner vertical wall portion 82 and the tunnel-side frame 63. Furthermore, the vehicle-inside corner portion 4a is positioned slightly lower than the upper end portion of the second vertical wall portion 63b.

[0137] On the other hand, the floor side frame 66 is provided so as to oppose, along the vehicle width direction, the corner portion 4b on the vehicle outer side of the upper end portion of the battery unit 4. The height position of the corner portion 4b on the vehicle outer side is higher than the connection position between the outer side vertical wall portion 81 and the floor side frame 66. Furthermore, the height position of the corner portion 4b on the vehicle outer side is slightly lower than the upper end portion of the floor side frame 66.

[0138] Here, if Figure 5 As shown by the dotted line, the corner 4b on the outside of the vehicle is cut out, thereby forming a vacant space 86 between the upper end of the battery unit 4 and the lower surface of the floor panel 61. Figure 8 As shown, the empty space 86 is disposed below the second fragile portion 674 .

[0139] Furthermore, piping components 91 extending in the vehicle front-rear direction are arranged on the vehicle outer side (left side in the illustration) of the vacant space 86. These piping components 91 are attached to the floor side frame 66 via brackets 92. By cutting out the corner portion 4b, the upper surface near the corner portion 4b is positioned on the vehicle lower side relative to the piping components 91. The piping components 91 can, for example, allow fuel to flow.

[0140] The piping components 91 are positioned in the vehicle height direction between the lower surface of the floor panel 61 and the flange portion 41a of the battery unit 4 that protrudes toward the vehicle outer side. In the vehicle width direction, the piping components 91 are positioned between the vacant space 86 and the floor side frame 66. The piping components 91 are also positioned below the first fragile portion 673.

[0141] (Regarding side impact performance)

[0142] As described above, by arranging the floor side frames 66 on the vehicle outer side and close to the rocker 64, the distance between the tunnel side frames 63 and the floor side frames 66 can be increased. When the distance between the tunnel side frames 63 and the floor side frames 66 is increased, the size of the battery unit 4 can be increased, thereby contributing to an increase in battery capacity.

[0143] However, when the battery capacity is increased as described above, the side surface of the battery unit 4 (particularly, the left side surface facing the vehicle outer side) also comes close to the rocker 64. If the side surface of the battery unit 4 comes close to the rocker 64, it is disadvantageous in side collision.

[0144] As a preparation for a side collision, it is also conceivable to provide a hollow energy absorbing member on the side of the battery unit 4. However, providing a new energy absorbing member is not suitable because it increases weight and costs.

[0145] Therefore, in the electric vehicle 1 according to this embodiment, by refining the shape of the mounting bracket 8, it is possible to achieve both an increase in the battery capacity of the battery unit 4 and protection of the battery unit 4 during a side collision without increasing weight or cost. Specifically, in this embodiment, the connection position between the inner vertical wall portion 82 and the tunnel side frame 63 is located higher in the vehicle than the connection position between the outer vertical wall portion 81 and the floor side frame 66.

[0146] Figure 9 This is a diagram illustrating the transition of the swing of the battery unit 4 during a side collision of the electric vehicle 1. Step S1 shows a state in which the mounting bracket 8 starts to swing due to a side collision.

[0147] As described above, the connection point between the outer vertical wall portion 81 and the floor-side frame 66 is located lower in the vehicle than the connection point between the inner vertical wall portion 82 and the tunnel-side frame 63. Therefore, when a load is applied from the side of the electric vehicle 1 (particularly, when a load is applied from the side relative to a position above the floor panel 61 on the vehicle, as indicated by arrow F), the outer vertical wall portion 81 is more likely to receive a load directed downward from the vehicle than the inner vertical wall portion 82. This load causes the outer vertical wall portion 81 to displace downward from the vehicle, allowing the mounting bracket 8 to swing like a swing with the connection point P between the inner vertical wall portion 82 and the tunnel-side frame 63 serving as the fulcrum.

[0148] Step S2 shows the state where the mounting bracket 8 is swung. By swinging the mounting bracket 8, the battery unit 4, supported by the lower wall 80 of the mounting bracket 8, can also swing toward the lower side of the vehicle. This swinging tilts the battery unit 4 so that the portion outside the vehicle is displaced downward.

[0149] Furthermore, when a load is applied from the side of the electric vehicle 1, the floor cross member 67 is subjected to a load that causes it to bend. By providing the fragile portions 673 and 674 configured as described above, the floor cross member 67 can be bent so as to protrude upward from the vehicle. By swinging the battery cells 4 downward from the vehicle and causing the floor cross member 67 to protrude upward from the vehicle, as shown in step S2, interference between the floor cross member 67 and the battery cells 4 can be suppressed. This contributes to the effective protection of the battery cells 4.

[0150] Although not shown, in step S2, the piping components 91 are displaced toward the vehicle interior. However, as described above, by swinging the battery unit 4 downward and protruding the floor cross member 67 upward, and by providing the aforementioned vacant space 86, interference between the piping components 91 and the upper surface of the battery unit 4 and between the piping components 91 and the floor cross member 67 can be effectively suppressed. Furthermore, by cutting away the corner portion 4b of the battery unit 4 to provide the vacant space 86, the piping components 91 are easily guided upward in the vehicle when the upper surface around the corner portion 4b contacts the piping components 91.

[0151] Step S3 shows the state where the mounting bracket 8 is further swung. As the mounting bracket 8 further sways, the battery unit 4 also further sways, allowing the battery unit 4 to retreat toward the lower side of the vehicle. By retreating the battery unit 4 toward the lower side of the vehicle, interference with vehicle components J, such as the rocker 64, which are crushed inward, can be avoided, effectively protecting the battery unit 4.

[0152] Thus, even when the floor side frame 66 is arranged on the vehicle outer side and close to the rocker 64, the battery unit 4 can be well protected. In this regard, the electric vehicle 1 can achieve both increased battery capacity and battery protection during a side collision without increasing weight or cost.

[0153] Furthermore, if mounting bracket 8 further swings, the corner portion 4a of battery unit 4 on the vehicle's inner side may come into contact with second vertical wall portion 63b. However, by steeply inclining second vertical wall portion 63b as described above, corner portion 4a that comes into contact with second vertical wall portion 63b can be smoothly guided downward in the vehicle, compared to, for example, a configuration in which second vertical wall portion 63b extends parallel to the vehicle's vertical direction. This advantageously protects battery unit 4.

[0154] In addition, by configuring the inner width Wi, which is the width of the inner longitudinal wall portion 82 in the vehicle front-rear direction, to be shorter than the outer width Wo, which is the width of the outer longitudinal wall portion 81 in the vehicle front-rear direction, the swinging of the mounting bracket 8 with the connection position between the inner longitudinal wall portion 82 and the tunnel side frame 63 as the fulcrum P can be promoted.

[0155] In addition, if you use Figure 10 As described above, by configuring the straight lines L1 and L2 so that they do not intersect the opening 85, deformation of the mounting bracket 8 due to loads input along the straight lines L1 and L2 can be suppressed. This achieves a balance between promoting swing due to the lightweighting of the mounting bracket 8 and ensuring the rigidity of the mounting bracket 8.

[0156] In addition, in the above embodiment, the inner longitudinal wall portion 82 is composed of the first inner longitudinal wall portion 82a and the second inner longitudinal wall portion 82b, but the present invention is not limited to such a structure. Figure 11 As shown in the mounting bracket 8', the inner longitudinal wall portion 82' is formed by a single inner longitudinal wall portion. In this case, the inner width Wi' corresponds to the width of the single inner longitudinal wall portion in the vehicle front-rear direction. By setting this inner width Wi' shorter than the outer width Wo', similar to the above-described embodiment, the swinging of the mounting bracket 8' is facilitated, while also effectively protecting the battery unit supported by its lower wall portion 80'.

[0157] In addition, Figure 11 In the example shown, the outer vertical wall portion 81 ′ is formed of one plate-like body as in the above embodiment, but may be formed of two or more plate-like bodies as in the case of the inner vertical wall portion 82 according to the above embodiment.

[0158] In addition, the technology disclosed herein is not limited to application to four-wheel drive vehicles, and can also be applied to front-engine rear-drive vehicles.

Claims

1. A lower structure of an electric vehicle, characterized in that: have: a floor panel provided with a floor tunnel extending in the front-rear direction of the vehicle; tunnel side frames, the tunnel side frames being arranged below the floor panel in the vehicle and at both sides of the floor tunnel in the vehicle width direction; a floor side frame disposed below the floor panel in the vehicle and disposed outward in the vehicle width direction relative to the tunnel side frame; a battery unit disposed below the floor panel in the vehicle and between the tunnel side frame and the floor side frame in the vehicle width direction; as well as A mounting bracket is formed so as to span from the tunnel side frame to the floor side frame in the vehicle width direction and connects the battery unit to the tunnel side frame and the floor side frame. The mounting bracket has: a lower wall portion supporting a bottom portion of the battery cell; an outer longitudinal wall portion extending upward from an end portion of the lower wall portion on the vehicle outer side and connected to the floor side frame; and an inner longitudinal wall portion extending upward from an end portion of the lower wall portion on the inner side of the vehicle and connected to the tunnel side frame; The connection position between the inner vertical wall portion and the tunnel side frame is located above the vehicle as compared to the connection position between the outer vertical wall portion and the floor side frame. The lower structure of the electric vehicle includes floor cross members, which are arranged on the floor panel and are arranged to span both sides of the floor panel in the vehicle width direction. A fragile portion is formed on the vehicle lower side of the floor cross member. The fragile portion is configured to promote bending of the floor cross member toward the vehicle upper side when a load is input from the vehicle side.

2. The lower structure of the electric vehicle according to claim 1, characterized in that: The width of the inner vertical wall portion in the vehicle front-rear direction is shorter than the width of the outer vertical wall portion in the vehicle front-rear direction.

3. The lower structure of the electric vehicle according to claim 2, characterized in that: The inner longitudinal wall portion has: a first inner longitudinal wall portion connected to the tunnel side frame; and a second inner longitudinal wall portion, the second inner longitudinal wall portion being arranged to be aligned with the first inner longitudinal wall portion in the vehicle front-rear direction and connected to the tunnel side frame; A total width of the first inner vertical wall portion and the second inner vertical wall portion in the vehicle front-rear direction is shorter than a width of the outer vertical wall portion in the vehicle front-rear direction.

4. The lower structure of an electric vehicle according to any one of claims 1 to 3, characterized in that: The channel side frame has: a first vertical wall portion that faces the vehicle inner side of the floor tunnel and is inclined toward the vehicle inner side as it goes toward the vehicle upper side; and a second vertical wall portion facing the vehicle outer side of the floor tunnel and inclined toward the vehicle outer side as it goes toward the vehicle upper side; The second vertical wall portion is provided to face a vehicle inner corner portion of an upper end portion of the battery unit in the vehicle width direction and is formed to be more steeply inclined than the first vertical wall portion with respect to the vehicle up-down direction.

5. The lower structure of the electric vehicle according to claim 1, characterized in that: The fragile portion is arranged on the vehicle outer side relative to the tunnel side frame in the vehicle width direction. A corner portion of the upper end portion of the battery unit on the vehicle outer side is cut away, thereby forming a vacant space between the upper end portion of the battery unit and the lower surface of the floor panel. Pipe components extending in the vehicle front-rear direction are arranged on the vehicle outer side of the empty space.

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