Lower vehicle body structure of vehicle

Abstract

The invention provides a lower vehicle body structure of a vehicle, which can ensure safety when a collision load is input and can ensure a high degree of freedom of a design related to the arrangement of a seat in a cabin. A vehicle is provided with a floor panel, a vehicle seat, a battery disposed below the floor panel, and a battery outer cross member (8) extending in the vehicle width direction between the floor panel and a battery case. A battery case (71) in a battery has internal beams (725-727) extending in the front-rear direction below a lid (73) and connecting outer peripheral walls facing each other in a case main body (72). The battery outer cross beam (8) is fixed to the inner beams (725-727) in a state of sandwiching the cover body (73), and is fixed to the seat rail in a state of sandwiching the floor panel.

Description

Technical Field

[0001] The present invention relates to a vehicle lower body structure, and more particularly to a vehicle lower body structure in which a battery is disposed below a floor panel. Background Art

[0002] In recent years, battery electric vehicles (BEVs) and hybrid electric vehicles (HEVs) have rapidly gained popularity. In these electric vehicles, large batteries are mounted beneath the floor panel. Patent Document 1 discloses a vehicle in which a seat frame is fixed to a battery housing mounted beneath the floor panel.

[0003] The vehicle disclosed in Patent Document 1 includes a body-side cross member connecting the side sills and the center tunnel in the vehicle width direction on the floor panel, and a battery-side cross member extending in the vehicle width direction, provided below the battery case cover. An inner seat frame, located on the vehicle width inner side of the seat frame, is fixed to the center tunnel and fastened to the body-side cross member using bolts. An outer seat frame, located on the vehicle width outer side, is fixed to the side sills and fastened to the body-side cross member using bolts.

[0004] The battery-side cross member is fastened to the inner and outer seat frames using bolts.

[0005]

Prior art literature

[0006] [Technical problem to be solved by the invention] The vehicle disclosed in Patent Document 1 above struggles to achieve both safety during collision loads and design freedom regarding the seat configuration within the cabin. Specifically, in the vehicle disclosed in Patent Document 1, the top panels of the seat frames on both the inner and outer sides of the vehicle are positioned to overlie the vehicle body's side transverse frames at the intersections with the vehicle body's side cross members. The inner seat frames are fixed to the center tunnel, while the outer seat frames are fixed to the side members. Therefore, if the height of the vehicle body's side cross members is to be maintained to a certain degree to ensure safety during collision loads, the seat frames must be positioned higher. Thus, in the vehicle disclosed in Patent Document 1 above, it is difficult to maintain the required height of the vehicle body's side cross members for safety while also lowering the seat frames.

[0007] Furthermore, the position of the seat frames in the vehicle width direction has limited design flexibility due to their relationship to the center tunnel and side sills. Specifically, if the seat frames are to be positioned away from the center tunnel and side sills, the spacing between the seat frames in the vehicle width direction must be increased, which poses a problem in terms of the stability of the seats mounted to these seat frames.

[0008] The present invention is directed to solving the above-mentioned problems, and its object is to provide a vehicle lower body structure that can ensure safety when a collision load is input and can ensure a high degree of freedom in the design related to the seat configuration in the cabin.

[0009]

Technical means to solve technical problems

[0010] In the lower body structure of the vehicle involved in the above-mentioned form, the battery case includes: a case body portion, which is a box having an outer peripheral wall and an upper opening; a cover portion, which blocks the opening of the case body portion; an internal frame portion, which extends in the case body portion in a second direction intersecting both the up and down direction of the vehicle and the first direction and connects the mutually opposing parts of the outer peripheral wall; the external frame portion is fixed to the internal frame portion in a state of clamping the cover portion, and is fixed to the seat rail in a state of clamping the floor panel.

[0011] In the vehicle underbody structure of the above-described embodiment, the external frame is disposed between the floor panel and the battery case, i.e., below the floor panel. Therefore, even when the cross-sectional height of the external frame is specified to ensure vehicle body rigidity, the height position of the seat rails (the height position of the vehicle seat) relative to the floor panel is not affected.

[0012] Furthermore, in the vehicle lower body structure of the above-described embodiment, the seat rails are secured to the battery housing via an external frame. The battery housing has high rigidity, protecting the battery cells housed therein from impact loads and other factors. Therefore, in the vehicle lower body structure of the above-described embodiment, securing the seat rails to the highly rigid battery housing prevents unwanted vibrations in the vehicle seat. Consequently, superior vehicle seat comfort can be achieved.

[0013] In the vehicle lower body structure according to the above embodiment, the external frame portion may be formed integrally with the battery case lid or separately therefrom. Furthermore, in the vehicle lower body structure according to the above embodiment, the internal frame portion may be formed integrally with the case body or separately therefrom.

[0014] In the vehicle lower body structure according to the above-described aspect, when the external frame portion is the first external frame portion, the structure may further include a second external frame portion, the second external frame portion being an external frame portion different from the first external frame portion and disposed between the floor panel and the battery case, the second external frame portion extending in the first direction and spaced apart from the first external frame portion in the second direction; and when the internal frame portion is the first internal frame portion, the battery case may further include a second internal frame portion disposed within the case body portion, extending in the second direction, spaced apart from the first internal frame portion in the first direction, and connected between the opposing portions of the outer peripheral wall of the case body portion; the second internal frame portion being fixed to the first and second external frame portions, respectively, while sandwiching the cover portion; the second external frame portion being fixed to the first internal frame portion while sandwiching the cover portion, and being fixed to the seat rails while sandwiching the floor panel.

[0015] In the lower body structure of the vehicle involved in the above-mentioned form, a second external skeleton portion is also provided, and the battery case also has a second internal skeleton member. The first internal skeleton portion and the second internal skeleton portion are fixed to the first external skeleton portion and the second external skeleton portion, respectively. There is a gap between the first external skeleton portion and the second external skeleton portion in the second direction, and there is a gap between the first internal skeleton portion and the second internal skeleton portion in the first direction. Thus, in the lower body structure of the vehicle involved in the above-mentioned form, in a plan view viewed from one direction in the up and down directions, the first external skeleton portion and the second external skeleton portion and the first internal skeleton portion and the second internal skeleton portion of the battery case form a rectangular lattice structure portion. Therefore, high rigidity can be ensured under the floor panel, and high safety can be ensured during a vehicle collision (frontal collision, side collision).

[0016] Furthermore, since the seat rails are fixed to the first and second outer frame portions, they are also fixed to the highly rigid rectangular lattice structure. This prevents unwanted vibrations from occurring in the vehicle seat within the vehicle's lower body structure, thereby achieving superior riding comfort.

[0017] In the vehicle lower body structure according to the above aspect, the external frame portion may be formed separately from the cover portion of the battery case and may be directly placed on the cover portion.

[0018] In the vehicle lower body structure according to the above aspect, the external frame portion is directly mounted on the cover portion of the battery case. Therefore, the external frame portion is directly mounted on the cover portion, which extends in a direction intersecting the vertical direction. Therefore, during a vehicle collision, for example, the load input to the external frame portion is also dispersed toward the cover portion. Consequently, the above vehicle lower body structure is advantageously able to ensure higher vehicle body rigidity.

[0019] Furthermore, in the vehicle lower body structure according to the above embodiment, the external frame portion and the cover portion are formed separately, so the position of the external frame portion relative to the cover portion can be determined according to the vehicle layout. Consequently, the cover portion and external frame portion can be made common across multiple vehicle models, thereby reducing manufacturing costs.

[0020] In the vehicle lower body structure according to the above aspect, the seat rails may be directly placed on the floor panel.

[0021] In the vehicle lower body structure according to the above embodiment, the seat rails are directly mounted on the floor panel, so the floor panel is directly sandwiched between the seat rails and the outer frame. Therefore, the floor panel is fixed to the mutually fixed outer frame and inner frame, which can prevent membrane vibration of the floor panel.

[0022] In the vehicle lower body structure according to the above aspect, the first direction may be the vehicle width direction, and the second direction may be the front-rear direction.

[0023] In the vehicle underbody structure according to the above embodiment, the vehicle width direction is defined as the first direction, and the fore-and-aft direction is defined as the second direction. Therefore, in a side collision, the collision load input to the external frame portion can be resisted by cooperating with the internal frame portion. In a frontal collision, the collision load input to the internal frame portion can be resisted by cooperating with the external frame portion. Therefore, the vehicle underbody structure according to the above embodiment can ensure high safety in both frontal and side collisions.

[0024] In the vehicle lower body structure according to the above aspect, in the first direction, the outer peripheral wall of the case body may be arranged so as to abut against or be close to side members arranged on both sides in the vehicle width direction.

[0025] In the vehicle lower body structure according to the above embodiment, the outer peripheral wall of the battery housing main body portion is arranged to abut or approach the side sill. Therefore, during a side collision, the impact load input to the side sill is dispersed through the outer peripheral wall of the battery housing to the inner and outer frame portions. Therefore, the vehicle lower body structure according to the above embodiment is advantageously able to ensure high safety during side collisions.

[0026] In the vehicle lower body structure according to the above aspect, the outer peripheral wall may include an outwardly facing protrusion that abuts against or comes close to a lower side surface of the side member.

[0027] In the vehicle lower body structure according to the above-described aspect, the outer peripheral wall of the battery housing main body portion includes an outwardly facing protrusion. This outwardly facing protrusion is positioned to abut or approach the lower side of the side sill, thereby preventing the battery from moving vertically during vehicle travel. Consequently, in the vehicle lower body structure according to the above-described aspect, by preventing the battery from moving vertically during vehicle travel, membrane vibration of the floor panel secured to the battery housing via the external frame portion can be prevented. Consequently, in the vehicle according to the above-described aspect, vibration within the cabin can be prevented, ensuring high passenger comfort.

[0028] In the vehicle lower body structure according to the above aspect, the internal frame portion may be formed separately from the case main body portion of the battery case and fixed to the outer peripheral wall of the case main body portion.

[0029] In the vehicle lower body structure according to the above aspect, the external frame portion may be a cross member provided on the vehicle body, and the internal frame portion may be an internal beam provided inside the battery.

[0030] In the vehicle lower body structure according to the above aspect, the internal frame portion is fixed to the outer peripheral wall of the case main body portion in the battery case, and therefore, high rigidity of the case main body portion can be ensured.

[0031] Furthermore, by fixing the internal frame portion to the outer peripheral wall of the case body portion, it is possible to prevent damage to the battery cells housed inside the battery case during a vehicle collision.

[0032] Furthermore, in the vehicle lower body structure according to the above-described embodiment, the internal frame portion is formed separately from the casing body portion. Therefore, the position of the internal frame portion relative to the casing body portion can be determined according to the arrangement of the battery cells in the battery, the shape of the casing body portion, etc. Therefore, by attaching a common internal frame portion to batteries of various shapes, manufacturing costs can be reduced.

[0033] Effects of the invention In the vehicle lower body structure according to each of the above-described aspects, safety can be ensured when a collision load is input, and a high degree of freedom in designing the seat arrangement in the cabin can be ensured. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a plan view of a portion of a vehicle to which a lower vehicle body structure according to an embodiment of the present invention is applied; Figure 2 This is an expanded oblique view of the battery and the battery outer beam; Figure 3 A plan view of the structure of the housing body of the battery housing; Figure 4 A plan view of the fixing structure of the internal beam of the shell body and the external cross beam of the battery; Figure 5 A cross-sectional view of the fixing structure of the right beam and the side beam of the shell body; Figure 6 A plan view of the fixing structure for the battery outer crossbeam and seat rails; Figure 7 A cross-sectional view of the fixing structure of the battery outer crossbeam and seat rails. DETAILED DESCRIPTION

[0035] The embodiments of the present invention will be described below with reference to the accompanying drawings. The embodiments described below are merely examples of the present invention, and the present invention is not limited to the embodiments described below except for its essential structure.

[0036] In the drawings used in the following description, “FR” indicates the front of the vehicle, “RR” indicates the rear of the vehicle, “LH” indicates the left side of the vehicle, “RH” indicates the right side of the vehicle, “UP” indicates the upper side of the vehicle, and “LO” indicates the lower side of the vehicle.

[0037] 1. Structure of vehicle 1 use Figure 1 The structure of a vehicle 1 to which the lower vehicle body structure according to the present embodiment is applied will be described. Figure 1 1 shows only a part of the structure of the vehicle 1 , and the illustration of the powertrain and the like is omitted.

[0038] like Figure 1 As shown, vehicle 1 includes a powertrain mounting portion 1a at the front, where the powertrain is mounted, and a passenger compartment 1b located rearward of powertrain mounting portion 1a, where passengers sit. A floor panel 3 is provided at the bottom of passenger compartment 1b. Vehicle seats 4 and 5 are provided on floor panel 3. Of these seats 4 and 5, the front seat 4 includes seat rails 6 provided on floor panel 3. The front seat 4 is slidable in the fore-and-aft direction within the range provided by the seat rails 6.

[0039] Both side portions of the floor panel 3 in the vehicle width direction are fixed to the side members 2 . Figure 1 Although not particularly shown in the figure, a center tunnel may be provided in the portion between the left and right vehicle seats 4 on the front side.

[0040] A battery 7 for supplying power to the powertrain is disposed below the floor panel 3. The vehicle 1 according to this embodiment is a battery electric vehicle (BEV) having a powertrain comprising only a driving motor, or a hybrid electric vehicle (HEV) having a powertrain comprising both a driving motor and an engine.

[0041] 2. Battery 7 and its surrounding structures use Figure 2 and Figure 3 The battery 7 disposed under the floor panel 3 and its surrounding structure will be described.

[0042] like Figure 2 As shown, the battery 7 includes a plurality of battery cells 70 and a flat rectangular parallelepiped battery case 71 that accommodates the plurality of battery cells 70. The plurality of battery cells 70 are each composed of a lithium-ion battery, a nickel-metal hydride battery, or the like. Figure 2 In the embodiment shown in the figure, each battery cell 70 has a square outer package, but the outer shape of the battery cell 70 is not limited thereto. For example, a battery cell having a cylindrical or laminate outer package (pouch-shaped outer package) may also be used.

[0043] The battery case 71 includes a case body 72 which is a box with an upper opening, and a cover 73 which closes the opening of the case body 72. Figure 3 As shown, the housing body 72 includes: beams 721 to 724 as the outer peripheral wall forming the lattice-shaped frame, a plurality of (three in this embodiment as an example) internal beams (internal frame portion) 725 to 727 connecting the front beam 721 and the rear beam 722, and a bottom plate 720 forming the bottom. Figure 2 As shown, a plurality of battery cells 70 are housed in a space defined by beams 721 to 724 and internal beams 725 to 727 .

[0044] The inner beams 725 to 727 extend in the front-rear direction (the second direction) along the beams 723 and 724, respectively, and are arranged with spaces therebetween in the vehicle width direction (the first direction). Figure 2 As shown, the upper sides of the internal beams 725 to 727 are arranged at a lower position than the upper sides of the beams 721 to 724 constituting the frame. Therefore, when the opening of the housing body 72 is closed by the cover 73, the upper sides of the internal beams 725 to 727 do not directly contact the lower side of the cover 73.

[0045] The cover 73 is fixed to the beams 721 to 724 and the internal beams 725 to 727 in a state where it is arranged to close the opening of the case body 72 .

[0046] Two battery outer cross members (external frame members) 8 are placed on the lid 73. The two battery outer cross members 8 extend in the vehicle width direction (first direction) and are spaced apart from each other in the front-to-rear direction (second direction). In this embodiment, the battery outer cross members 8 are formed separately from the lid 73 and placed directly on the lid 73. Specifically, the battery outer cross members 8 are positioned between the lid 73 and the floor panel 3.

[0047] In this embodiment, the battery outer cross beam 8 is formed separately from the cover portion 73, but the battery outer cross beam 8 may be formed integrally with the cover portion 73. Furthermore, the front beam 721 and the rear beam 722 of the internal beams 725-727 and the beams 721-724 constituting the frame body may be fixed by welding or by bolt fastening. Furthermore, the internal beams 725-727 and the beams 721-724 may be formed integrally.

[0048] 3. Fixing the battery outer crossbeam 8 and inner beams 725-727 use Figure 4 The fixing method of the battery outer cross beam 8 and the internal beams 725-727 is described. Figure 4 It is a plan view of the battery outer beam 8 and the inner beams 725 to 727 fixed with the cover portion 73 interposed therebetween.

[0049] like Figure 4 As shown, the two battery outer cross members 8 are spaced apart from each other in the front-rear direction. In contrast, the plurality of inner beams 725-727 are spaced apart from each other in the vehicle width direction. Furthermore, the battery outer cross member 8 and the inner beams 725-727 are arranged substantially orthogonally in a plan view.

[0050] The battery outer cross beam 8 and the inner beams 725-727 are fixed at the intersection of each other. Figure 4 As shown in the cross-section of the figure, a collar 728 is fixed to the upper portions of the inner beams 725-727 (only the inner beam 727 is shown in the cross-section). A female screw is formed downward from the upper end surface of the collar 728. Bolts 729, inserted through opening 8a in the upper portion of the battery outer cross-beam 8, are then fastened to the female screw of the collar 728. This secures the battery outer cross-beam 8 and the inner beams 725-727 at their intersection (fixing point JP1).

[0051] As described above, the battery outer cross beam 8 and the inner beams 725 to 727 are fixed at the fixing portion JP1 , thereby forming a rectangular lattice structure portion (rectangular lattice structure portion) HR1 in a plan view.

[0052] like Figure 4 As shown in the cross-section of FIG, in this embodiment, a gap G is provided between the upper side of the collar 728 and the lower side of the cover 73. This ensures that, even if manufacturing errors occur between the internal beams 725-727 and the collar 728, a fastening force is applied between the battery outer cross member 8 and the internal beams 725-727, ensuring a secure connection between them. This also prevents the collar 728 and the cover 73 from contacting or separating due to vibrations during driving, which could cause unusual noises.

[0053] 4. Positioning of the battery housing 71 relative to the side member 2 use Figure 5 The arrangement of the battery case 71 with respect to the side member 2 will be described. Figure 5 7 , the side member 2 on the right side of the vehicle body and the right side portion of the battery case 71 are selected and illustrated, and the side member 2 on the left side of the vehicle body and the left side portion of the battery case 71 are arranged in the same structure.

[0054] like Figure 5 As shown, the vehicle widthwise end of the floor panel 3 is fixed to the upper side of the side sill 2 while being placed thereon. The side sill 2 is constructed by fixing a pair of hat-shaped components 21 and 22 to each other. The floor panel 3 is fixed to the component 22 on the inner side of the side sill 2 in the vehicle widthwise direction.

[0055] The battery outer cross member 8 is positioned vertically sandwiched between the floor panel 3 and the battery case 71. The ends of the battery outer cross member 8 in the vehicle width direction are positioned to abut or approach the inner side surfaces of the components 22 of the side sills 2. When the ends of the battery outer cross member 8 in the vehicle width direction abut or approach the inner side surfaces of the components 22 of the side sills 2, the battery outer cross member 8 extends in the vehicle width direction on the cover portion 73 to connect the left and right side sills 2, supporting the floor panel 3 and forming part of the vehicle body's frame structure as a cross member. In other words, the battery outer cross member 8 can be a vehicle body frame member such as a floor frame.

[0056] The housing body 72 of the battery housing 71 is also arranged to abut or be close to the component 22 of the side member 2. The left and right beams 723, 724 (see Figure 3 ) has an outward convex portion 723a, which protrudes outward in the vehicle width direction and abuts or comes close to the lower side surface of the component 22 in the side member 2.

[0057] 5. Fixing the seat rail 6 and the battery outer crossbeam 8 between the floor panel 3 use Figure 6 and Figure 7 The method of fixing the seat rails 6 and the battery outer cross member 8 sandwiching the floor panel 3 will be described.

[0058] like Figure 6 As shown, the two battery outer cross members 8 are spaced apart from each other in the front-rear direction. In contrast, the four seat rails 6 are spaced apart from each other in the vehicle width direction. Furthermore, the battery outer cross members 8 and the seat rails 6 are arranged substantially orthogonally in a plan view.

[0059] The battery outer cross beam 8 and the seat rail 6 are fixed at the intersection of each other. Figure 7 As shown, the seat rail 6 has a downwardly projecting protrusion 6a. It is secured to the battery outer cross member 8 by bolts 61 that extend from the inside of this protrusion 6a through the floor panel 3 and into the battery outer cross member 8. Bolts 61 are inserted through openings 6b provided in the upper portion of the seat rail 6 and screwed into nuts 81 inserted through openings 8b provided in the lower portion of the battery outer cross member 8. This secures the battery outer cross member 8 and the seat rail 6 at their intersection (fixing point JP2).

[0060] In this embodiment, each seat rail 6 is positioned between the beams 721-724 and the inner beams 725-727 of the housing body 72 in the vehicle width direction. However, the placement of the seat rail 6 is determined by the arrangement of the vehicle seats 4 in the cabin portion 1b. Therefore, each seat rail 6 is not limited to being positioned between the beams 721-724 and the inner beams 725-727 in the vehicle width direction.

[0061] As described above, by fixing the battery outer cross member 8 and the seat rail 6 at the fixing portion JP2 , the battery outer cross member 8 and the seat rail 6 form a rectangular lattice structure portion (rectangular lattice structure portion) HR2 in a plan view.

[0062] 6. Effect In vehicle 1 employing the lower vehicle body structure according to this embodiment, battery outer cross member (external frame portion) 8 is disposed between floor panel 3 and battery case 71, i.e., below floor panel 3. Therefore, even when the cross-sectional height of battery outer cross member 8 is specified to ensure vehicle body rigidity, the height position of seat rail 6 (the height position of vehicle seat 4) relative to floor panel 3 is not affected.

[0063] Furthermore, in vehicle 1, seat rails 6 are secured to inner beams 725-727 of battery case 71 via battery outer cross member 8. Therefore, in vehicle 1, securing seat rails 6 to inner beams 725-727 of battery case 71 prevents unwanted vibrations from occurring in vehicle seat 4. Consequently, superior riding comfort in vehicle seat 4 can be achieved.

[0064] In this embodiment, the battery outer crossbeam 8 and the cover portion 73 of the battery case 71 are formed as separate components, but the battery outer crossbeam 8 can also be formed integrally with the cover portion 73. Furthermore, in this embodiment, the internal beams (internal frame portion) 725-727 are formed separately from the case body portion 72 and fixed to each other, but the internal beams 725-727 can also be formed integrally with the case body portion 72.

[0065] Furthermore, in the vehicle 1 to which the lower vehicle body structure according to the present embodiment is applied, two battery outer cross beams (a first outer cross beam and a second outer cross beam) 8 are provided as an external frame portion. Furthermore, three internal beams (including a first internal cross beam and a second internal cross beam) 725 to 727 are fixed to the two battery outer cross beams 8, respectively. The two battery outer cross beams 8 are arranged with spaces therebetween in the front-rear direction (the second direction), and the three internal beams 725 to 727 are arranged with spaces therebetween in the vehicle width direction (the first direction). Thus, in the vehicle 1, in a plan view viewed from one direction in the vertical direction, the two battery outer cross beams 8 and the three internal beams 725 to 727 of the battery case 71 form a rectangular lattice structure portion HR1 (see FIG. 1 ). Figure 4 ). Therefore, high rigidity can be ensured under the floor panel 3, and high safety can be ensured during a vehicle collision (frontal collision or side collision).

[0066] Furthermore, since the seat rails 6 are fixed to the two battery outer cross members 8, they are also fixed to the highly rigid rectangular lattice structure HR1. Consequently, in the vehicle 1, undesirable vibrations of the vehicle seat 4 can be prevented, thereby ensuring superior riding comfort in the vehicle seat 4.

[0067] In the vehicle 1 employing the lower vehicle body structure according to this embodiment, the two battery outer cross members 8 are mounted directly on the cover portion 73 of the battery case 71. Therefore, during a vehicle collision or the like, the load input to the battery outer cross members 8 is dispersed toward the cover portion 73, which spreads in a direction intersecting the vehicle vertical direction. This contributes to ensuring higher vehicle body rigidity in the vehicle 1.

[0068] Furthermore, in vehicle 1, the battery outer cross member 8 and the cover portion 73 are provided separately. Therefore, the position of the battery outer cross member 8 relative to the cover portion 73 can be determined according to the layout of vehicle 1. Consequently, the cover portion 73 and the battery outer cross member 8 can be common to multiple vehicle models, thereby reducing manufacturing costs.

[0069] In vehicle 1 employing the lower vehicle body structure according to this embodiment, the seat rails 6 are placed directly on the floor panel 3. Therefore, the floor panel 3 is directly sandwiched between the seat rails 6 and the battery outer cross member 8. Therefore, the floor panel 3 is fixed to the mutually fixed battery outer cross member 8 and inner beams 725 to 727, thereby preventing membrane vibration of the floor panel 3.

[0070] In vehicle 1 employing the lower vehicle body structure according to this embodiment, battery outer cross member 8 extends in the vehicle width direction, while inner cross members 725-727 extend in the front-rear direction. Therefore, in a side collision, the battery outer cross member 8 can cooperate with the inner cross members 725-727 to resist the collision load applied to battery outer cross member 8. In a frontal collision, the battery outer cross member 8 can also cooperate with the inner cross members 725-727 to resist the collision load applied to battery outer cross member 8. Consequently, vehicle 1 can ensure high safety in both frontal and side collisions.

[0071] In vehicle 1 employing the lower vehicle body structure according to this embodiment, the left and right beams (outer peripheral walls) 723 and 724 of the battery case main body 72 are arranged in contact with or close to the side members 2. Therefore, during a side collision, the collision load input to the side members 2 is distributed via the beams 721 to 724 forming the outer peripheral walls of the battery case 71 to the inner beams 725 to 727 and the battery outer cross member 8. This contributes to ensuring high safety in vehicle 1 during a side collision.

[0072] In vehicle 1 employing the lower vehicle body structure according to this embodiment, the left and right beams (outer peripheral walls) 723 and 724 of the case body 72 of the battery case 71 have outwardly projecting portions 723a. These outwardly projecting portions 723a are positioned to abut or approach the lower surfaces of the side beams 2, thereby preventing vertical movement of the battery 7 during vehicle travel. Consequently, in vehicle 1, by preventing vertical movement of the battery 7 during vehicle travel, membrane vibration of the floor panel 3, which is secured to the battery case 71 via the battery outer cross beam 8, can be prevented. Consequently, in vehicle 1, vibration within the cabin portion 1b can be suppressed, ensuring high passenger comfort.

[0073] In the vehicle 1 to which the lower vehicle body structure according to this embodiment is applied, the inner beams 725 to 727 are fixed to the front and rear beams (outer peripheral walls) 721 and 722 of the case body 72 in the battery case 71 , thereby ensuring high rigidity of the case body 72 .

[0074] Furthermore, by fixing the internal beams 725 to 727 to the front and rear beams 721 and 722 of the case body 72 , it is possible to prevent the battery cells 70 housed inside the battery case 71 from being damaged during a vehicle collision.

[0075] Furthermore, in vehicle 1, since the internal beams 725-727 are formed separately from the case body 72, the positions of the internal beams 725-727 relative to the case body 72 can be determined according to the arrangement of the battery cells 70 in the battery 7, the shape of the case body 72, and the like. Therefore, by attaching the common internal beams 725-727 to batteries 7 of various shapes, manufacturing costs can be reduced.

[0076] As described above, in the vehicle 1 to which the lower vehicle body structure according to this embodiment is applied, safety can be ensured when a collision load is input, and a high degree of freedom in design regarding the arrangement of the vehicle seats 4 in the cabin portion 1 b can be ensured.

[0077] [Variation] In the above embodiment, the battery outer cross beam 8 and the cover portion 73 of the battery case 71 are provided separately. However, the present invention can also form the outer frame portion and the cover portion of the battery case integrally.

[0078] Furthermore, in the above embodiment, the internal beams 725-727 are fixed to the front and rear beams 721, 722 of the housing body 72. However, in the present invention, it is not necessary to fix the internal frame to the outer peripheral wall of the housing body. As long as load transmission is possible, the internal frame may also abut or be close to the outer peripheral wall of the housing body.

[0079] Furthermore, in the above embodiment, the front vehicle seat 4 of the front and rear vehicle seats 4 and 5 includes seat rails 6 and is capable of sliding forward and backward. However, the present invention can also include seat rails for the rear vehicle seat and be capable of sliding forward and backward. In this case, the seat rails included in the rear vehicle seat are also fixed to the external frame portion, thereby achieving the same effects as described above.

[0080] In addition, in the above embodiment, two battery outer cross beams 8 and three internal beams 725 to 727 are provided, but the present invention only needs to include at least one external frame portion and at least one internal frame portion.

[0081] In the above embodiment, the rectangular lattice structure portion HR1 and the rectangular lattice structure portion HR2 are respectively rectangular or square in plan view. However, in the present invention, the rectangular lattice structure portion may be a rhombus, parallelogram, or trapezoidal in plan view.

[0082] In addition, in the above embodiment, a structure is adopted in which the battery outer cross beam 8 extends in the vehicle width direction and the internal beams 725~727 extend in the front-to-back direction, but in the present invention, a structure can also be adopted in which the external skeleton part extends in the front-to-back direction and the internal skeleton part extends in the vehicle width direction.

[0083] Furthermore, in the above embodiment, the left and right beams 723 and 724 of the housing body 72 have the outward convex portions 723 a . However, in the present invention, the housing body does not necessarily need to have the outward convex portions.

[0084] In the above embodiment, the materials constituting the battery outer cross member 8 and the inner beams 725 to 727 are not specifically mentioned; however, any material that can be used as a vehicle frame member can be used. For example, metal materials such as steel and aluminum alloys, or resin materials such as carbon fiber reinforced resin, can be used.

[0085]

Number Description

Claims

1. A vehicle lower body structure comprising: a floor panel constituting a cabin floor in the vehicle; a vehicle seat comprising seat rails disposed on the floor panel; an outer frame portion extending in a first direction, which is one of the front-rear direction and the vehicle width direction of the vehicle, and arranged below the floor panel; A battery having a battery core and a battery housing for housing the battery core, and disposed below the outer frame portion; wherein, The battery case comprises: a case body portion which is a box having an outer peripheral wall and an upper opening; a cover portion that blocks the opening of the housing body; an internal frame portion that extends within the housing body in a second direction that intersects both the up-down direction of the vehicle and the first direction and is connected between mutually opposing portions of the outer peripheral wall; The outer frame portion is fixed to the inner frame portion with the cover portion interposed therebetween, and is also fixed to the seat rail with the floor panel interposed therebetween.

2. The vehicle lower body structure according to claim 1, wherein: When the external frame portion is a first external frame portion, a second external frame portion is further provided, the second external frame portion being an external frame portion different from the first external frame portion and being arranged between the floor panel and the battery case, the second external frame portion extending in the first direction and being spaced apart from the first external frame portion in the second direction; When the internal skeleton portion is the first internal skeleton portion, the battery case further comprises a second internal skeleton portion, the second internal skeleton portion being arranged within the case body portion, extending in the second direction and spaced apart from the first internal skeleton portion in the first direction, and connected between the opposing portions of the outer peripheral wall of the case body portion; The second inner frame portion is fixed to the first outer frame portion and the second outer frame portion respectively while sandwiching the cover portion. The second outer frame portion is fixed to the first inner frame portion with the cover portion interposed therebetween, and is fixed to the seat rail with the floor panel interposed therebetween.

3. The vehicle lower body structure according to claim 1, wherein: The external frame portion is formed separately from the cover portion of the battery case and is directly placed on the cover portion.

4. The vehicle lower body structure according to claim 1, wherein: The seat rails are directly placed on the floor panel.

5. The vehicle lower body structure according to any one of claims 1 to 4, characterized in that: The first direction is the vehicle width direction, The second direction is the front-rear direction.

6. The vehicle lower body structure according to claim 5, wherein: In the first direction, the outer peripheral wall of the housing body is arranged so as to abut against or be close to side members arranged on both sides in the vehicle width direction.

7. The vehicle lower body structure according to claim 6, wherein: The outer peripheral wall has an outward convex portion that abuts against or is close to the lower side surface of the side member.

8. The vehicle lower body structure according to any one of claims 1 to 4, characterized in that: The internal skeleton portion is formed separately from the case main body portion of the battery case and is fixed to the outer peripheral wall of the case main body portion.

9. The vehicle lower body structure according to any one of claims 1 to 4, characterized in that: The external frame portion is a cross member provided on the vehicle body, and the internal frame portion is an internal beam provided inside the battery.

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