Battery box for vehicle

Abstract

A vehicle battery box (10) is provided with: a lower panel (11) on which a battery can be placed; a pair of rocker structural members (12) which are joined to both side ends of the lower panel (11) in the vehicle width direction and which are capable of absorbing energy of an impact acting from the vehicle width direction; and a battery cross member (15) provided on the upper side of the lower panel (11), both ends of the battery cross member (15) in the vehicle width direction being joined to the pair of rocker structural members (12), respectively, and the front-side ends of the pair of rocker structural members (12) being removably joined to a vehicle body front structure constituting the front of the vehicle body. The rear end of the rear side is detachably joined to a vehicle body rear structure constituting the rear part of the vehicle body.

Description

Technical Field

[0001] The present invention relates to a battery box for a vehicle. Background Art

[0002] Patent Documents 1 and 2 disclose a vehicle lower structure including a battery box for a vehicle. The vehicle lower structure disclosed in Patent Document 1 includes: a battery box that is disposed below a floor panel of a vehicle body and houses a battery; and a battery box mounting frame that connects a side sill provided on a lateral side in the vehicle width direction of the battery box to the battery box and supports the battery box. The battery box mounting frame has: an upper frame that engages with the battery box to support the battery box; and a lower frame that is formed below the upper frame and engages with the side sill. The upper frame constitutes a side frame of the battery box. The lower frame functions as an energy absorption member that absorbs energy of a load applied in the vehicle width direction.

[0003] In addition, the vehicle lower structure disclosed in Patent Document 2 includes: a pair of side sills that are respectively disposed on both outer sides of a floor panel of a vehicle body in the vehicle width direction; and a battery storage assembly that is disposed on a lower side of the floor panel. The pair of side sills are each formed in a tubular shape with a closed cross-sectional shape, and an energy absorption member is disposed inside. The battery storage assembly has a drive battery (battery pack) and a vehicle battery box that houses the drive battery. In addition, the vehicle battery box has: a bottom panel on which the drive battery is placed; and side frames that are respectively joined to both end portions in the vehicle width direction of the bottom panel and extend in the vehicle front-rear direction. Moreover, the side sills are disposed on the outer sides in the vehicle width direction of the side frames. That is, the side frames of the vehicle battery and the side sills are arranged side by side in the vehicle width direction.

[0004] In addition, when a load (e.g., an impact load generated by a side collision) acts on a vehicle having the vehicle lower structure described in Patent Document 2 from the side, the load is absorbed by the energy absorption portion within the side sill, thereby suppressing deformation of the battery box. Here, generally, an energy absorption member is configured to deform from the side where the load acts, i.e., from the outer side in the vehicle width direction, when the load acts on the energy absorption member from the outer side in the vehicle width direction. That is to say, the energy absorption member is configured such that the portion constituting the outer side in the vehicle width direction in the energy absorption portion is more easily deformed than the portion constituting the inner side in the vehicle width direction. However, in this case, the portion constituting the outer side in the vehicle width direction deforms around the portion of the energy absorption member on which the load is applied, and thus the load is concentrated only on the deformed portion. That is, only the deformed portion of the energy absorption member effectively contributes to energy absorption, and the other portions do not contribute to energy absorption. Therefore, the load dispersion effect is weakened, and it may not be possible to efficiently absorb the energy of the load. Accordingly, further improvement for more effectively absorbing the energy of the load is desired.

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2022-124191

[0008] Patent Document 2: Japanese Unexamined Patent Application Publication No. 2018-188124 Summary of the Invention

[0009] In view of the above actual situation, one object of the present invention is to provide a vehicle battery box for housing a driving battery, which can further increase the cruising range of a vehicle that travels using electric power supplied from the driving battery. Another object of the present invention is to provide a vehicle battery box for housing a driving battery, which can more effectively absorb the energy of a load.

[0010] (Technical Solution for Solving Technical Problems)

[0011] The vehicle battery box according to the present invention houses a driving battery that supplies power to a driving source of a vehicle. The vehicle battery box includes: a plate-shaped bottom panel that is disposed substantially horizontally below a floor panel of a vehicle body, and on which the driving battery is placed on an upper surface thereof; a pair of lower side beam structural members that are configured as cylindrical members that are respectively joined to both side ends in a vehicle width direction of the bottom panel and extend along a vehicle front-rear direction, and an energy absorption portion configured to be able to absorb energy of a load acting in the vehicle width direction is provided in the pair of lower side beam structural members; and a battery cross member that is provided on the upper surface of the bottom panel, extends in the vehicle width direction, and both ends in the vehicle width direction are respectively joined to inner surfaces in the vehicle width direction of the pair of lower side beam structural members. Further, the energy absorption portion includes: a first load transfer portion that is provided at a position that overlaps a floor cross member provided on the floor panel and extending in the vehicle width direction when viewed from the vehicle width direction; and a second load transfer portion that is provided at a position that overlaps the battery cross member when viewed from the vehicle width direction.

[0012] According to the present invention, by providing the lower side beam structural member having the above-described structure in the vehicle battery box, even if the side frame of the vehicle battery box is removed, deformation of the battery housing space due to a load from the outside in the vehicle width direction can be prevented or suppressed, and the space for housing the battery can be expanded in the vehicle width direction by removing the side frame of the vehicle battery box. Further, in the present invention, it can be said that "the pair of lower side beam structural members also serve as the side frame of the vehicle battery box".

[0013] Specifically, the lower side beam structural member includes an energy absorption portion, and the energy absorption portion includes a first load transfer portion and a second load transfer portion. Therefore, when a load (for example, an impact load generated due to a side collision) is applied to the vehicle equipped with the vehicle battery box according to the present invention from the outside in the vehicle width direction, the load is absorbed by the energy absorption portion of the lower side beam structural member of the vehicle battery box. Further, the first load transfer portion and the second load transfer portion are arranged to overlap the floor cross member and the battery cross member respectively when viewed from the vehicle width direction. Therefore, the load that is not completely absorbed by the energy absorption portion is dispersed to a path from the first load transfer portion to the floor cross member and a path from the second load transfer portion to the battery cross member. Therefore, compared with the case where the load transfer path is one, the load transferred to the floor cross member and the battery cross member can be increased within a range where deformation of the vehicle battery box can be suppressed. Therefore, deformation of the battery housing space due to a load from the outside in the vehicle width direction can be prevented or suppressed.

[0014] In addition, for a structure with two load transfer paths, compared with a structure with one path, even if the energy absorption amount of the energy absorption part of the lower side beam structural component is reduced, deformation of the vehicle battery box can be suppressed. That is, the energy absorption part can be compactly formed. By compactly forming the energy absorption part, the widthwise dimension of the lower side beam structural component can be reduced. In addition, in the vehicle battery box according to the present invention, since the energy absorption part is provided in the lower side beam structural component, there is no need to ensure a space for arranging the energy absorption part outside the lower side beam structural component, and the accommodation space for the drive battery on the lower panel can be further expanded by this space amount. Thereby, the loading amount of the drive battery can be increased.

[0015] Moreover, according to the present invention, a pair of cylindrical lower side beam structural components provided at both lateral ends in the vehicle width direction of the lower panel also serve as side frames of the vehicle battery box. In other words, the side frames of the vehicle battery box are formed by the lower side beams. Therefore, compared with a structure in which the lower side beam and the side frame are arranged side by side in the vehicle width direction, there is no need to ensure a space for arranging the side frame, so that the accommodation space for the drive battery on the lower panel can be expanded in the vehicle width direction. Thereby, the loading amount of the drive battery can be increased. As a result, the cruising range of a vehicle powered by electric power supplied from the drive battery can be further improved. As a result, the accommodation space for the drive battery on the lower panel in the vehicle width direction can be further expanded, and by loading more drive batteries in the expanded accommodation space, the cruising range of the vehicle can be further improved.

[0016] The vehicle battery box according to the present invention houses a drive battery that supplies electric power to a drive source of a vehicle, and the vehicle battery box includes: a plate-shaped lower panel that is disposed substantially horizontally below a floor panel of a vehicle body, and on which a drive battery is placed on an upper surface thereof; and a pair of lower side beam structural components that are respectively disposed at both lateral ends in the vehicle width direction of the lower panel, and an energy absorption part configured to be able to absorb energy of a load acting in the vehicle width direction is provided in the pair of lower side beam structural components. In addition, the energy absorption part includes: an in-vehicle energy absorption part; and an out-of-vehicle energy absorption part that is joined to the in-vehicle energy absorption part and is formed on the outer side in the vehicle width direction compared with the in-vehicle energy absorption part. Moreover, the out-of-vehicle energy absorption part is configured to be more difficult to deform than the in-vehicle energy absorption part.

[0017] According to the present invention, the vehicle outer energy absorption part that constitutes the vehicle width direction outer side in the energy absorption part provided in the lower side beam structural part is configured to be more difficult to deform than the vehicle inner energy absorption part that constitutes the vehicle width direction inner side. Therefore, when a load (for example, an impact load generated due to a side collision) is applied to the vehicle battery box from the vehicle width direction outer side, the vehicle inner energy absorption part compresses and deforms in the vehicle width direction earlier than the vehicle outer energy absorption part. Here, when the vehicle inner energy absorption part starts to deform, the vehicle outer energy absorption part is in a state of being undeformed or having little deformation. Therefore, the load acting on the vehicle outer energy absorption part in the undeformed state or the state of having little deformation is dispersed over the entire range where the vehicle outer energy absorption part is disposed, and due to the large-range compression deformation of the vehicle inner energy absorption part, the energy generated by the load is absorbed. In this way, the load is also transmitted to the vehicle inner energy absorption part over a large range, so a larger range of the vehicle inner energy absorption part can be used to efficiently absorb the load.

[0018] The energy that cannot be absorbed by the compression deformation of the vehicle inner energy absorption part is absorbed by the compression deformation of the vehicle outer energy absorption part and the deformation such as the lower side beam structural part entering the vehicle width direction inner side. However, according to the present invention, since the amount of energy absorbed by the vehicle inner energy absorption part can be increased, the effect of preventing or suppressing the deformation of the lower side beam structural part in the manner of entering the vehicle width direction inner side can be improved. Therefore, the effect of preventing or suppressing the situation of contacting the battery due to the lower side beam structural part entering the space where the battery is placed (in other words, the effect of protecting the battery) can be improved.

[0019] The vehicle battery box according to the present invention houses a drive battery that supplies power to a drive source of the vehicle. The vehicle battery box includes: a plate-shaped lower panel that is disposed substantially horizontally below the floor panel of the vehicle body, and the drive battery is placed on the upper surface of the lower panel; a pair of lower side beam structural parts that are configured as cylindrical parts that are respectively joined to both ends in the vehicle width direction of the lower panel and extend along the vehicle front-rear direction. The pair of lower side beam structural parts are joined to a vehicle body front part structure that constitutes the front part of the vehicle body at the front end side, and are joined to a vehicle body rear part structure that constitutes the rear part of the vehicle body at the rear end side at the rear side. An energy absorption part that is configured to be able to absorb a load acting from the vehicle width direction is provided inside the pair of lower side beam structural parts; and a battery cross member that is disposed on the upper surface of the lower panel and extends in the vehicle width direction, and both ends in the vehicle width direction of the battery cross member are respectively joined to the inner surfaces in the vehicle width direction of the pair of lower side beam structural parts.

[0020] According to the present invention, a pair of cylindrical lower side beam structural components provided at both side ends in the vehicle width direction of the lower panel are configured as the lower side beam of the vehicle body by being joined to the front body structure and the rear body structure, and also serve as the side frames of the vehicle battery box. In other words, the lower side beam, which is a strength component of the vehicle body, is constituted by components (strength components of the vehicle battery box) that make up the vehicle battery box. Therefore, compared with a structure in which the lower side beam and the side frame are arranged side by side in the vehicle width direction, the accommodation space for the drive battery in the vehicle battery box in the vehicle width direction is enlarged. As a result, the loading capacity of the drive battery can be increased, and thus the cruising range of a vehicle that obtains driving force from a drive source driven by electric power supplied from the drive battery can be further improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is an exploded perspective view showing the structure of the battery box and the bottom of the vehicle body.

[0022] Figure 2 is an exploded perspective view showing the structure of the battery box and the bottom of the vehicle body.

[0023] Figure 3 is a perspective view showing the structure of the battery box and the bottom of the vehicle body.

[0024] Figure 4A is a perspective view showing the structure of the front protruding end portion.

[0025] Figure 4B is a perspective view showing the structure of the front protruding end portion.

[0026] Figure 5A is a perspective view showing the structure of the mounting portion.

[0027] Figure 5B is a perspective view showing the structure of the mounting portion.

[0028] Figure 6 is a cross-sectional view showing the structure of the lower side beam structural component of the battery box.

[0029] Figure 7 is a cross-sectional view showing the structure of the lower side beam structural component of the battery box. DETAILED DESCRIPTION OF THE INVENTION

[0030] Hereinafter, embodiments of the present invention will be described. In the following description, the vehicle battery box may sometimes be abbreviated as the "battery box". The battery box according to this embodiment is applied to vehicles such as electric vehicles and hybrid vehicles that have an electric motor as a driving source for driving, and is configured to be able to accommodate a driving battery (hereinafter sometimes abbreviated as "battery") that supplies power to the electric motor serving as the driving source for driving. Moreover, the battery box according to this embodiment is configured to be detachable from and attachable to the vehicle body bottom. That is, the lower structure of the vehicle includes the battery box according to this embodiment and the vehicle body bottom.

[0031] In the following description, the directions of the battery box and its structural components are based on the directions of the vehicle. In each figure, the front side of the vehicle is indicated by an arrow Fr, the rear side by an arrow Rr, the right side in the vehicle width direction (left-right direction) by an arrow R, the left side in the vehicle width direction by an arrow L, the upper side by an arrow Up, and the lower side by an arrow Dw. Additionally, the outer side in the vehicle width direction may sometimes be indicated by an arrow Out (hereinafter sometimes referred to as the "vehicle outer side"), and the inner side in the vehicle width direction by an arrow In (hereinafter sometimes referred to as the "vehicle inner side").

[0032] (Structure of the battery box)

[0033] Figures 1 to 3 is a perspective view showing the structure of the battery box 10 and the vehicle body bottom 20 to which the battery box 10 is assembled. In addition, Figure 1 is an exploded perspective view observed from obliquely above, Figure 2 is an exploded perspective view observed from obliquely below, Figure 3 is a perspective view showing the state in which the battery box 10 is assembled to the vehicle body bottom 20 and observed from obliquely below.

[0034] The battery box 10 includes a lower panel 11, a pair of left and right lower side beam structural members 12, a front frame 13, a rear frame 14, a plurality of battery cross members 15, and an upper panel 16 (see Figure 6 ). And the battery box 10 is configured to be able to accommodate the battery inside. Specifically, when viewed in the up-down direction, the battery box 10 has a substantially quadrilateral shape (however, the front ends and the rear ends of the pair of left and right lower side beam structural members 12 protrude in the front-rear direction. Details will be described later), and has a box-shaped structure with a hollow interior. And the lower panel 11 corresponds to the "bottom of the box", the upper panel 16 corresponds to the "lid of the box", and the pair of left and right lower side beam structural members 12, the front frame 13, and the rear frame 14 correspond to the "side walls of the box".

[0035] The lower panel 11 is a plate-shaped component and is disposed substantially horizontally (in a direction extending in the vehicle width direction and the front-rear direction). In addition, in the present embodiment, the lower panel 11 has a substantially quadrilateral (rectangular) shape when viewed in the vertical direction. The lower panel 11 is formed of, for example, a plate material of aluminum or an aluminum alloy. A placement surface 111, which is a surface on which a battery can be placed, is provided on the upper surface of the lower panel 11. In addition, a temperature control fluid path 112 (see Figure 6 ) is provided inside the lower panel 11, and the temperature control fluid path 112 is configured to allow a temperature control fluid for adjusting the temperature of the battery placed on the placement surface 111 to flow therethrough. For example, the lower panel 11 includes two plate-shaped components that are overlapped and joined in the vertical direction, and the temperature control fluid path 112 is provided between these two plate-shaped components.

[0036] The pair of left and right lower side beam structural components 12 each have a cylindrical structure with a substantially quadrilateral cross section cut by a plane perpendicular to the length direction. For example, an extrusion material made of aluminum or an aluminum alloy is applied to the pair of left and right lower side beam structural components 12. The pair of left and right lower side beam structural components 12 are disposed separately from each other in the left-right direction (vehicle width direction) with their length directions substantially parallel to the front-rear direction of the vehicle. And, the pair of left and right lower side beam structural components 12 are respectively joined to both side ends in the vehicle width direction of the lower panel 11. More specifically, the lower surfaces of the pair of left and right lower side beam structural components 12 are joined to the upper surfaces of both side ends in the vehicle width direction of the lower panel 11 respectively. The pair of left and right lower side beam structural components 12 include energy absorption portions 401, 402 (details will be described later) configured to be able to absorb energy of an impact applied from the outside of the vehicle.

[0037] Both the front frame 13 and the rear frame 14 have a cylindrical structure with a space formed inside. For example, an extrusion material made of aluminum or an aluminum alloy is applied to the front frame 13 and the rear frame 14. The front frame 13 and the rear frame 14 are disposed separately from each other in the front-rear direction with their length directions substantially parallel to the vehicle width direction. And, the front frame 13 is joined to the front end portion of the lower panel 11, and the rear frame 14 is joined to the rear end portion of the lower panel 11. More specifically, the lower surfaces of the front frame 13 and the rear frame 14 are joined to the upper surfaces of the front end portion and the rear end portion of the lower panel 11 respectively.

[0038] A plurality of battery cross members 15 are formed in a long strip shape and are members having a substantially hat-shaped cross-sectional shape perpendicular to the longitudinal direction (sometimes referred to as "hat-section members"). For the plurality of battery cross members 15, an extrusion material or a stamping material made of, for example, aluminum or an aluminum alloy is applied. The plurality of battery cross members 15 are arranged on the upper side of the lower panel 11 so as to be separated from each other in the front-rear direction (in other words, arranged in the front-rear direction) with their longitudinal directions substantially parallel to the vehicle width direction. Further, the lower surfaces of the plurality of battery cross members 15 (that is, the portions corresponding to the flanges of the hat shape) are joined (for example, welded) to the upper surface of the lower panel 11. In addition, the end portions in the longitudinal direction of the plurality of battery cross members 15 are joined to the inner side surfaces of the left and right pair of lower side beam structural members 12 via mounting fittings 17. Further, the upper surfaces of the plurality of battery cross members 15 are located below the upper surfaces of the left and right pair of lower side beam structural members 12 (see Figure 6 ). In addition, the structure of the mounting fittings 17 is not particularly limited. However, the mounting fittings 17 join the battery cross members 15 to the left and right pair of lower side beam structural members 12 firmly (in other words, in such a manner as not to allow relative movement between the battery cross members 15 and the left and right pair of lower side beam structural members 12) so that the load in the vehicle width direction applied to the left and right pair of lower side beam structural members 12 can be transmitted to the battery cross members 15.

[0039] The plurality of battery cross members 15 have a function of improving the rigidity (difficulty of deformation) in the vehicle width direction of the battery box 10. That is, when a side collision or the like occurs to the vehicle, an impact load (force) pressing inward of the vehicle is applied to the left and right pair of lower side beam structural members 12. The plurality of battery cross members 15 prevent or suppress a situation in which the left and right pair of lower side beam structural members 12 are deformed in a manner of entering the vehicle interior and contacting the battery due to receiving such a load.

[0040] The upper panel 16 (omitted in Figure 1 ; see Figure 6 ) is a plate-shaped member having a substantially quadrilateral shape when viewed in the up-down direction and is arranged substantially horizontally. The upper panel 16 is formed of, for example, a plate material of aluminum or an aluminum alloy. The upper panel 16 is arranged so as to cover between the left and right pair of lower side beam structural members 12 and above the lower panel 11, the front frame 13, the rear frame 14, and the plurality of battery cross members 15. Further, the upper panel 16 is arranged below the upper surfaces of the left and right pair of lower side beam structural members 12. That is, the upper surface of the upper panel 16 is located below the upper surfaces of the left and right pair of lower side beam structural members 12. In addition, the upper panel 16 is detachably mounted on the left and right pair of lower side beam structural members 12, the front frame 13, and the rear frame 14.

[0041] A pair of left and right lower side beam structural components 12, a front frame 13, a rear frame 14, and a plurality of battery cross beams 15 form the skeleton of the battery box 10. In addition, when the battery box 10 is installed on the vehicle body bottom 20 of the vehicle, the pair of left and right lower side beam structural components 12 also function as lower side beams, which are strength components of the vehicle. That is, the pair of left and right lower side beam structural components 12 of the battery box 10 constitute a part of the vehicle's skeleton. In addition, the lower side beam of the vehicle refers to a component that constitutes a part of the vehicle's skeleton (more specifically, a part of the vehicle body bottom 20), has a tubular structure (in other words, has a closed cross-sectional shape), and is arranged on the vehicle outer side of the vehicle's center floor panel 22 with its longitudinal direction substantially parallel to the front-rear direction.

[0042] Moreover, an internal space is formed in the battery box 10 and is surrounded by the bottom panel 11, the pair of left and right lower side beam structural components 12, the front frame 13, the rear frame 14, and the top panel 16. The upper surface of the bottom panel 11 in this internal space is formed into a plurality of partitions by the plurality of battery cross beams 15 (specifically, the partitions between adjacent battery cross beams 15 and the partition between the rearmost battery cross beam 15 and the rear frame 14). And each partition can carry batteries (specifically, battery modules formed by connecting a plurality of battery cells) (that is, can be accommodated in the internal space of the battery box 10).

[0043] In addition, the front end portions of the pair of left and right lower side beam structural components 12 protrude forward compared with the front end portion of the bottom panel 11 and the front end portion (front surface) of the front frame 13. Sometimes these parts are denoted as front protruding end portions 121. Similarly, the rear end portions of the pair of left and right lower side beam structural components 12 protrude rearward compared with the rear end portion of the bottom panel 11 and the rear end portion (rear surface) of the rear frame 14. Sometimes these parts are denoted as rear protruding end portions 122. The front protruding end portions 121 are configured to be detachable from the pair of left and right torsion boxes 25 of the vehicle body bottom 20 described later respectively, and the rear protruding end portions 122 are configured to be detachable from the pair of left and right rear longitudinal beams 28 of the vehicle body bottom 20 described later respectively.

[0044] (Structure of the vehicle body bottom)

[0045] Next, the vehicle body bottom 20 of the vehicle will be described. The vehicle body bottom 20 includes a pair of left and right lower side beam skin components 21, a center floor panel 22, a plurality of floor cross beams 23, a pair of left and right torsion boxes 25, a pair of left and right front longitudinal beams 26, a front bumper reinforcement 27, a pair of left and right rear longitudinal beams 28, a rear bumper reinforcement (not shown), and a rear floor panel 29.

[0046] A pair of left and right lower side member skin components 21 are elongated components. The pair of left and right lower side member skin components 21 are disposed substantially parallel to each other in a state where they are located at the lower part of the vehicle and at the outer ends in the vehicle width direction, with their longitudinal directions being substantially parallel to the longitudinal direction of the vehicle. The front end portions of the pair of left and right lower side member skin components 21 are respectively joined to a pair of left and right torque boxes 25. The rear end portions of the pair of left and right lower side member skin components 21 are respectively joined to a pair of left and right rear longitudinal members 28. Moreover, a plurality of floor cross members 23 are joined to the pair of left and right lower side member skin components 21. In addition, the lower end portions of a front pillar, a middle pillar, and a rear pillar (not shown) may be respectively joined to the pair of left and right lower side member skin components 21.

[0047] The pair of left and right lower side member skin components 21 are each configured to be able to cover the left and right lower side member skin components of the battery box 10 mounted on the vehicle body bottom 20 of the vehicle from above. Specifically, the pair of left and right lower side member skin components 21 include an outer vehicle side covering portion 211, an upper covering portion 212, and an inner vehicle side covering portion 213. The outer vehicle side covering portion 211 is the portion of the lower side member skin component 21 that is closest to the outer side of the vehicle, and is a portion having a plate-like structure that extends in the vertical direction and the longitudinal direction and is relatively long in the longitudinal direction. The upper covering portion 212 is the portion located above the lower side member skin component 21. The upper covering portion 212 is a portion that extends from the upper end (upper side) of the outer vehicle side covering portion 211 toward the inner side of the vehicle, and has a flat plate-like structure that extends in the longitudinal direction and the vehicle width direction and is relatively long in the longitudinal direction. The inner vehicle side covering portion 213 is the portion located at the upper part of the inner side of the lower side member skin component 21. The inner vehicle side covering portion 213 is a portion having a rib-like structure that extends downward from the inner side end (inner side edge) of the upper covering portion 212. Therefore, the pair of left and right lower side member skin components 21 have a shape with a substantially "inverted J" cross-section.

[0048] Moreover, in a state where the battery box 10 is mounted on the vehicle body bottom 20 of the vehicle, the outer vehicle side covering portion 211 of the lower side member skin component 21 is located on the outer side of each of the pair of left and right lower side member structural components 12 (covering the outer side), the upper covering portion 212 is located above each of the pair of left and right lower side member structural components 12 (covering the upper side), and the inner vehicle side covering portion 213 is located near the upper end portion of the inner side of each of the pair of left and right lower side member structural components 12 (covering near the upper end portion of the inner side). In this way, the vehicle body bottom 20 of the vehicle is configured to be able to accommodate the battery box 10 between the outer vehicle side covering portions 211 of the pair of left and right lower side member skin components 21. And the vehicle body bottom 20 of the vehicle is configured to cover the pair of left and right lower side member structural components 12 of the battery box 10 in a state where the battery box 10 is mounted.

[0049] The central floor panel 22 is an example of the floor panel of the present invention. The central floor panel 22 is a component that constitutes the floor of the passenger compartment and has a plate-like structure extending in a substantially horizontal direction. In addition, the central floor panel 22 is substantially quadrilateral when viewed in the vertical direction. The left and right end portions (left and right sides) of the central floor panel 22 are respectively joined to a pair of left and right lower side member skin parts 21. And, the upper surface of the central floor panel 22 is located at a position lower than the upper surfaces of the pair of left and right lower side member skin parts 21. For example, the central floor panel 22 is joined to the lower end portion (lower side) or the vicinity thereof of the vehicle interior covering portion 213 of the pair of left and right lower side member skin parts 21.

[0050] The plurality of floor cross members 23 are long bar-shaped members having a substantially hat-shaped cross section and are arranged above the central floor panel 22 in a direction substantially parallel to the vehicle width direction in the longitudinal direction. In the present embodiment, the plurality of floor cross members 23 are components for mounting vehicle seats. In addition, the components among the plurality of floor cross members 23 on which vehicle seats are mounted are sometimes referred to as "seat cross members". And, the lower end portion (lower surface) of the floor cross member 23 is joined (fixed) to the central floor panel 22, and the end portions on the vehicle outer side in the longitudinal direction of the floor cross member 23 are joined (fixed) to the left and right lower side member skin parts 21. In addition, the lower surface of the floor cross member 23 is located below the upper covering portion 212 of the pair of left and right lower side member skin parts 21, and the upper surface of the floor cross member 23 is located above the upper covering portion 212 of the lower side member skin part 21. In addition, the upper surface of the floor cross member 23 may be set at the same height as the upper covering portion 212 of the lower side member skin part 21, or at a position lower than the upper covering portion 212.

[0051] In addition, in Figure 1 it is shown that the vehicle body bottom 20 has a structure in which a center frame 24 is located substantially at the center in the vehicle width direction and extends in the front-rear direction. In this case, the inner ends in the vehicle width direction of the plurality of floor cross members 23 are joined to the center frame 24. However, the vehicle body bottom 20 of the vehicle is not limited to such a structure, and the vehicle body bottom 20 of the vehicle may not have a center frame 24. In this case, the two end portions in the longitudinal direction of the plurality of floor cross members 23 are respectively joined to the pair of left and right lower side member skin parts 21. In other words, in this case, the plurality of floor cross members 23 are arranged in such a manner as to connect the pair of left and right lower side member skin parts 21.

[0052] A pair of left and right torsion boxes 25 are components that connect a pair of left and right lower side beam structural components 12 of a battery box 10 installed at the bottom 20 of a vehicle body to a pair of left and right front longitudinal beams 26 respectively. The pair of left and right torsion boxes 25 are arranged on the front side of a pair of left and right lower side beam skin components 21 and are respectively joined to the pair of left and right lower side beam skin components 21. In the present embodiment, the pair of left and right torsion boxes 25 are made of aluminum or an aluminum alloy and are manufactured by die casting. The pair of left and right torsion boxes 25 each include a mounting portion 60 configured to removably join (fix) the front protruding ends 121 of the pair of left and right lower side beam structural components 12 of the battery box 10. In addition, the mounting portion 60 will be described later.

[0053] A pair of left and right front longitudinal beams 26 are long cylindrical components. The pair of left and right front longitudinal beams 26 are arranged separately from each other in the left-right direction with their longitudinal directions substantially parallel to the front-rear direction. And the rear end portions of the pair of left and right front longitudinal beams 26 are respectively joined to the pair of left and right torsion boxes 25. The front end portions of the pair of left and right front longitudinal beams 26 are joined to a front bumper reinforcement 27. In addition, a pair of left and right suspension towers (not shown) are respectively joined to the pair of left and right front longitudinal beams 26. The pair of left and right suspension towers are configured to accommodate the suspensions of the left and right front wheels (a mechanism including a shock absorber and a coil spring).

[0054] The front bumper reinforcement 27 is arranged at the rear side of a front bumper (not shown), is configured to withstand the load applied to the front bumper (a force toward the rear of the vehicle), and transfer the withstood load to the pair of left and right front longitudinal beams 26. The front bumper reinforcement 27 is a rod-shaped component and is arranged with its longitudinal direction substantially parallel to the vehicle width direction.

[0055] A pair of left and right rear longitudinal beams 28 are components that connect a pair of left and right lower side beam structural components 12 of the battery box 10 to a rear bumper reinforcement (not shown) respectively. The pair of left and right rear longitudinal beams 28 are arranged on the rear side of the pair of left and right lower side beam skin components 21 and are joined to the front end portions of the pair of left and right lower side beam skin components 21 respectively. The rear end portions of the pair of left and right rear longitudinal beams 28 are joined to the rear bumper reinforcement. The rear bumper reinforcement is a long rod-shaped component and is arranged at the front side of a rear bumper (not shown) with its longitudinal direction substantially parallel to the vehicle width direction. And the rear bumper reinforcement is configured to withstand the load in the front-rear direction applied to the rear bumper and transfer the withstood load to the pair of left and right rear longitudinal beams 28.

[0056] Thus, at the front part of the vehicle body bottom 20, a front bumper reinforcement 27, a pair of left and right front side members 26, and a pair of left and right torsion boxes 25 are arranged. These components are strength components (components that form the framework of the vehicle body) that bear the load applied to the front bumper. In addition, at the rear part of the vehicle body bottom 20, a rear bumper reinforcement and a pair of left and right rear side members 28 are arranged. These components are strength components that bear the load applied to the rear bumper. Therefore, it can be said that "the vehicle body bottom 20 of the vehicle has a front body structure, and this front body structure has a front bumper reinforcement 27, a pair of left and right front side members 26, and a pair of left and right torsion boxes 25". In addition, it can be said that "the vehicle body bottom 20 of the vehicle has a rear body structure, and this rear body structure has a rear bumper reinforcement and a pair of left and right rear side members 28".

[0057] The rear floor panel 29 is a component that forms the floor of the trunk room and has a plate-like structure extending in a substantially horizontal direction. Both side ends in the vehicle width direction of the rear floor panel 29 are respectively joined to a pair of left and right rear side members 28. In addition, the front end portion of the rear floor panel 29 is joined to the rear end portion of the center floor panel 22.

[0058] The vehicle body bottom 20 of the vehicle according to the present embodiment does not have the conventional pair of left and right lower side members integrally joined to other strength components, but instead has a pair of left and right lower side member skin components 21 in place of the conventional pair of left and right lower side members. In addition, the structures of the torsion box 25, the front side member 26, the front bumper reinforcement 27, the rear side member 28, the rear bumper reinforcement, and the rear floor panel 29 are not limited, and conventional well-known structures can be applied.

[0059] Thus, the vehicle body bottom 20 is configured to be able to house the battery box 10 between the lower side of the upper covering portion 212 of the center floor panel 22 and the left and right lower side member skin components 21 and between the outer vehicle side covering portions 211 of the left and right lower side member skin components 21.

[0060] (Assembly structure of the battery box to the vehicle body bottom of the vehicle)

[0061] Next, the assembly structure of the battery box 10 to the vehicle body bottom 20 of the vehicle will be described. Figure 4A and Figure 4B are perspective views showing the structure of the front protruding end portion 121 of the side member structural component 12. In addition, Figure 4A is a view observed obliquely from the lower side of the vehicle outer side, Figure 4B is a view observed obliquely from the upper side of the vehicle inner side. Figure 5A and Figure 5B are perspective views showing the structure of the mounting portion 60 provided on the torsion box 25. In addition, Figure 5A is a view observed obliquely from the lower side of the vehicle outer side, Figure 5BIt is a view observed obliquely from the lower inner side of the vehicle.

[0062] As Figure 4A and Figure 4B shown, the lower side beam structural member 12 has an inner vehicle side wall portion 51 and an outer vehicle side wall portion 52 located on the outer side of the vehicle thereof. Both the inner vehicle side wall portion 51 and the outer vehicle side wall portion 52 are plate-shaped portions extending in the front-rear direction and the up-down direction (substantially vertically erected), separated in the vehicle width direction and arranged substantially parallel to each other. And, threaded holes 123 into which threaded members can be screwed and whose axes are substantially parallel to the vehicle width direction are provided in the outer vehicle side wall portion 52 and the inner vehicle side wall portion 51 in the front protruding end portion 121. Thus, a plurality of threaded holes 123 are provided on the inner side surface and the outer side surface of the front protruding end portion 121 of the vehicle (an example in which five threaded holes 123 are provided is shown in the figure).

[0063] As Figure 5A and Figure 5B shown, mounting portions 60 are provided on the pair of left and right torsion boxes 25. The mounting portions 60 are configured to be able to house the front protruding end portions 121 of the pair of left and right lower side beam structural members 12 respectively and be fixed in the housed state. Specifically, the mounting portion 60 has an inner vehicle side mounting wall portion 601 and an outer vehicle side mounting wall portion 602 located on the outer side of the vehicle thereof. The inner vehicle side mounting wall portion 601 and the outer vehicle side mounting wall portion 602 are plate-shaped portions erected substantially vertically, arranged substantially parallel to each other with a prescribed distance therebetween in the vehicle width direction. Moreover, in order to ensure strength, the mounting portion 60 has an upper side mounting wall portion 603 provided in a manner of connecting the upper end portions (upper sides) of the inner vehicle side mounting wall portion 601 and the outer vehicle side mounting wall portion 602 to each other. In addition, the lower side and the rear side of the mounting portion 60 are open so that the front protruding end portion 121 can be housed from the lower side. Therefore, the mounting portion 60 has a substantially "inverted U" shape that is open at the lower side when observed in the front-rear direction. And, the front protruding end portion 121 of the lower side beam structural member 12 can be housed between the inner vehicle side mounting wall portion 601 and the outer vehicle side mounting wall portion 602.

[0064] The vehicle outer side mounting wall portion 602 and the vehicle inner side mounting wall portion 601 are provided with threaded member insertion holes 604 through which threaded members for fixing the front protruding end portion 121 of the lower side beam structural member 12 can be inserted. Further, the front protruding end portion 121 of the lower side beam structural member 12 is inserted into the interior of the mounting portion 60 from below (is housed between the vehicle outer side mounting wall portion 602 and the vehicle inner side mounting wall portion 601 of the mounting portion 60), and in this state, screw fastening is performed from both the vehicle outer side of the vehicle outer side mounting wall portion 602 and the vehicle inner side of the vehicle inner side mounting wall portion 601. That is, the vehicle inner side wall portion 51 of the front protruding end portion 121 of the pair of left and right lower side beam structural members 12 is screw-fastened to the vehicle inner side mounting wall portion 601 of the mounting portion 60, and the vehicle outer side wall portion 52 of the front protruding end portion 121 is screw-fastened to the vehicle outer side mounting wall portion 602 of the mounting portion 60. Thereby, the front protruding end portion 121 is joined to the mounting portion 60. That is, the lower side beam structural member 12 is joined to the torque box 25. In this way, the front protruding end portion 121 is detachably joined to the mounting portion 60 of the torque box 25 by a threaded member that passes through the vehicle inner side mounting wall portion 601 from the vehicle width direction inner side of the vehicle inner side mounting wall portion 601 and engages with the vehicle inner side wall portion 51 (the portion of the vehicle inner side surface where the front protruding end portion 121 is provided) and a threaded member that passes through the vehicle outer side mounting wall portion 602 from the vehicle width direction outer side of the vehicle outer side mounting wall portion 602 and engages with the vehicle outer side wall portion 52 (the portion of the vehicle outer side surface where the front protruding end portion 121 is provided).

[0065] Each of the mounting portions 281 of the pair of left and right rear side members 28 is configured to be able to respectively accommodate the rear protruding ends 122 of the pair of left and right lower side member structural components 12, and to be fixed in the accommodated state. In addition, the rear protruding ends 122 of the pair of left and right lower side member structural components 12 have a structure that is substantially symmetric in the front-rear direction with the front protruding ends 121. Further, the mounting portions 281 respectively provided on the pair of left and right rear side members 28 have a structure that is substantially symmetric in the front-rear direction with the mounting portions 60 provided on the pair of left and right torsion boxes 25. Therefore, the description of the structures of the rear protruding ends 122 of the lower side member structural components 12 and the mounting portions 281 of the pair of left and right rear side members 28 is omitted. And, the rear protruding ends 122 of the lower side member structural components 12 are inserted into the inside of the mounting portions 281 from the lower side, and in this state, they are screwed from both the vehicle outer side of the vehicle outer mounting wall portion 602 and the vehicle inner side of the vehicle inner mounting wall portion 601. Thus, the rear protruding ends 122 are joined to the mounting portions 281. That is, the lower side member structural components 12 are joined to the rear side members 28. In this way, the rear protruding ends 122 are detachably joined to the mounting portions 281 of the rear side members 28 by screws that pass through the vehicle inner mounting wall portion 601 from the vehicle width direction inside of the vehicle inner mounting wall portion 601 and are screwed to the vehicle inner wall portion 51 (the portion of the vehicle inner side surface where the front protruding ends 121 are provided) and screws that pass through the vehicle outer mounting wall portion 602 from the vehicle width direction outside of the vehicle outer mounting wall portion 602 and are screwed to the vehicle outer wall portion 52 (the portion of the vehicle outer side surface where the front protruding ends 121 are provided).

[0066] In this way, the battery box 10 according to the present embodiment includes a cylindrical lower side member structural component 12, the front protruding end 121 (that is, the front end portion of the lower side member structural component 12) of the lower side member structural component 12 is joined to the torsion box 25, and the rear protruding end 122 (that is, the rear end portion of the lower side member structural component 12) of the lower side member structural component 12 is joined to the rear side member 28. The torsion box 25 is a component included in the front body structure and is a strength component that bears the load acting from the front. In addition, the rear side member 28 is a component included in the rear body structure and is a strength component that bears the load acting from the rear.

[0067] According to such a structure, a pair of left and right lower side beam structural members 12 of the battery box 10 function as lower side beams of the vehicle body bottom 20. That is, when an object collides with the front side of the vehicle, the load generated by the collision is transmitted to a pair of left and right torsion boxes 25 through the front bumper, the front bumper reinforcement 27, and a pair of left and right front side members 26. And since the front end portions of the pair of left and right lower side beam structural members 12 are fastened to the torsion boxes 25, the load applied to the torsion boxes 25 is borne by the pair of left and right lower side beam structural members 12. Thus, the load acting from the front of the vehicle is transmitted to the pair of left and right lower side beam structural members 12 via the front body structure. According to such a structure, the load acting from the front of the vehicle is transmitted to the pair of lower side beam structural members 12 via the front body structure.

[0068] On the other hand, when an object collides with the rear side of the vehicle, the load generated by the collision is transmitted to the rear side member 28 via the rear bumper and the rear bumper reinforcement. And since the rear end portions of the pair of left and right lower side beam structural members 12 are joined to the rear side member 28, the load applied to the rear side member 28 is borne by the pair of left and right lower side beam structural members 12. Thus, the load acting from the rear of the vehicle is transmitted to the pair of left and right lower side beam structural members 12 via the rear body structure. And the load transmitted to the rear side member 28 is borne by the pair of left and right lower side beam structural members 12. Thus, the load from the rear is also transmitted to the pair of left and right lower side beam structural members 12.

[0069] Then, the pair of left and right lower side beam structural members 12 bear the load in the front-rear direction (compressive load) (without deformation when loaded), thereby preventing or suppressing the compression deformation of the passenger compartment (cab) above the lower side beam structural members 12 in the front-rear direction. According to such a structure, a pair of cylindrical lower side beam structural members 12 provided at both side ends in the vehicle width direction of the lower panel 11 are configured as the lower side beams of the vehicle body by being joined to the front body structure (left and right torsion boxes 25) and the rear body structure (left and right rear side members 28), and also serve as the side frames of the battery box 10. In other words, the side frames of the battery box 10 are constituted by the lower side beams. Thereby, the battery placed on the placement surface 111 of the lower panel 11 between the pair of left and right lower side beam structural members 12 can be protected from the loads from the front and rear. In addition, according to the present embodiment, since the pair of left and right lower side beam structural members 12 function as the lower side beams of the vehicle body, the vehicle body bottom 20 of the vehicle may not have the conventional lower side beam integrated with other strength members.

[0070] Therefore, compared with the structure in which the side sills at the bottom of the vehicle body and the side frames of the battery box are arranged horizontally in the vehicle width direction in the past, there is no need to ensure a space for arranging the side frames. Therefore, the internal space (the mounting surface 111 of the lower panel 11) of the battery box 10 can be expanded in the vehicle width direction. As a result, the battery loading capacity can be increased, and as a result, the cruising range of a vehicle powered by electric power supplied from the battery can be further improved.

[0071] Moreover, in the present embodiment, the front protruding ends 121 and the rear protruding ends 122 of the pair of left and right side sill structural members 12 are respectively fixed to the torque box 25 and the rear longitudinal member 28 by threaded members on both sides in the vehicle width direction. That is, the surfaces (the surfaces on opposite sides, that is, the outer vehicle side surface facing the outside in the vehicle width direction and the inner vehicle side surface facing the inside in the vehicle width direction) of the front protruding end 121 and the rear protruding end 122 that are separately provided in the vehicle width direction are respectively joined to the front body structure and the rear body structure. With such a structure, the joint strength between the side sill structural member 12 and the torque box 25 and the rear longitudinal member 28 can be improved compared with a structure in which only one side in the vehicle width direction is fixed by a threaded member. Therefore, the rigidity of the vehicle body bottom 20 (for example, the rigidity against torsion centered on the vehicle front-rear direction) can be improved. Moreover, if it is a structure fastened by threaded members, the battery box 10 can be removed from the vehicle body bottom 20, and maintenance (replacement, repair, etc.) of the battery and the battery box 10 can be easily performed.

[0072] In addition, according to the present embodiment, the pair of side sill structural members 12 are respectively covered from above by the side sill skin member 21 provided in a manner of connecting (connecting) the front body structure and the rear body structure. Therefore, the side sill skin member 21 and the side sill structural member 12 can be made of different metals. Therefore, for example, the side sill skin member 21 can be made of a steel plate, and the side sill structural member 12 can be made of aluminum or an aluminum alloy. And by configuring in this way, for example, body parts such as pillars can be welded to the side sill skin member 21, and in addition, the side sill structural member 12 can be made of aluminum or the like to achieve weight reduction of the battery box 10.

[0073] In addition, by joining body parts such as struts (parts joined to the vehicle body bottom 20 or parts constituting the vehicle body bottom 20) to the side sill skin member 21, these body parts can be prevented from being directly joined to the pair of left and right side sill structural members 12 respectively. In other words, other body parts can be indirectly joined to the pair of left and right side sill structural members 12 via the side sill skin member 21. With such a structure, when the battery box 10 is installed on the vehicle body bottom 20, there is no need to perform the operation of joining the side sill structural members 12 of the battery box 10 to these body parts. In addition, with such a structure, the battery box 10 can be separated from these body parts.

[0074] (Structure of side sill structural member)

[0075] Next, the structure of the side sill structural member 12 will be described. The side sill structural member 12 is configured to transfer the load generated by a side collision or the like (when a load is applied from the outside of the vehicle toward the inside of the vehicle) to the battery cross member 15 and the floor cross member 23, and is configured to absorb the energy generated by a side collision or the like by being compressed and deformed in the vehicle width direction.

[0076] Figure 6 FIG. is a cross-sectional view showing the structure of the side sill structural member 12. As Figure 6 shown, the side sill structural member 12 includes: an outer frame portion 50 having a tubular structure with a substantially quadrilateral cross section and extending in the front-rear direction; and a plate-like intermediate longitudinal plate portion 55 formed inside the outer frame portion 50 and extending in the front-rear direction and the up-down direction (substantially vertically erected). The outer frame portion 50 includes: an inner vehicle side wall portion 51 located on the inner side of the vehicle; an outer vehicle side wall portion 52 located on the outer side of the vehicle with respect to the inner vehicle side wall portion 51; an upper wall portion 53 connecting the upper end portions (upper sides) of the inner vehicle side wall portion 51 and the outer vehicle side wall portion 52 to each other; and a lower wall portion 54 connecting the lower end portions (lower sides) of the inner vehicle side wall portion 51 and the outer vehicle side wall portion 52 to each other.

[0077] The inner vehicle side wall portion 51 and the outer vehicle side wall portion 52 are portions having a plate-like structure erected substantially vertically, and the upper wall portion 53 and the lower wall portion 54 are portions having a plate-like structure extending in the vehicle width direction and the front-rear direction (i.e., extending in a substantially horizontal direction). Further, the upper end portion (upper side) of the intermediate longitudinal plate portion 55 is joined to the upper wall portion 53, and the lower end portion (lower side) of the intermediate longitudinal plate portion 55 is joined to the lower wall portion 54. In addition, a temperature control fluid path housing portion 543 is provided in the lower wall portion 54. The temperature control fluid path housing portion 543 is a portion configured to be able to house a path member 18 (e.g., a tubular member) for supplying a temperature control fluid to the temperature control fluid path 112 provided in the lower panel 11, and has a groove-like structure extending in the front-rear direction and opening downward. With such a structure, the path member 18 can be disposed so as not to protrude from the lower surface of the lower wall portion 54, and thus the vertical dimension of the battery box 10 is not increased.

[0078] The upper wall portion 53 includes: an inner vehicle upper wall portion 531 that forms a portion closer to the inner side of the vehicle than the joining position with the intermediate longitudinal plate portion 55; and an outer vehicle upper wall portion 532 that forms a portion closer to the outer side of the vehicle than the joining position with the intermediate longitudinal plate portion 55. Similarly, the lower wall portion 54 includes: an inner vehicle lower wall portion 541 that forms a portion closer to the inner side of the vehicle than the joining position with the intermediate longitudinal plate portion 55; and an outer vehicle lower wall portion 542 that forms a portion closer to the outer side of the vehicle than the joining position with the intermediate longitudinal plate portion 55. Therefore, it can be said that the internal space of the outer frame portion 50 is divided by the intermediate longitudinal plate portion 55 into an inner vehicle space 501 located closer to the inner side of the vehicle than the intermediate longitudinal plate portion 55 and an outer vehicle space 502 located closer to the outer side of the vehicle than the intermediate longitudinal plate portion 55.

[0079] A plurality of inner vehicle transverse plate portions 56 that connect the intermediate longitudinal plate portion 55 and the inner vehicle side wall portion 51 are provided inside the inner vehicle space 501. Specifically, the plurality of inner vehicle transverse plate portions 56 include a first inner vehicle transverse plate portion 561 and a second inner vehicle transverse plate portion 562 located below it. Both the first inner vehicle transverse plate portion 561 and the second inner vehicle transverse plate portion 562 are plate-like portions extending in a substantially horizontal direction. Further, the outer ends of the first inner vehicle transverse plate portion 561 and the second inner vehicle transverse plate portion 562 are joined to the intermediate longitudinal plate portion 55, and the inner ends are joined to the inner vehicle side wall portion 51.

[0080] The upper wall portion 53 and the first inner vehicle transverse plate portion 561 are disposed at positions overlapping the floor cross member 23 when viewed in the vehicle width direction in a state where the battery box 10 is mounted on the vehicle body bottom 20. In other words, the upper wall portion 53 and the first inner vehicle transverse plate portion 561 are positioned in the vertical direction lower than the upper surface of the floor cross member 23 and higher than the lower surface of the floor cross member 23 in a state where the battery box 10 is mounted on the vehicle body bottom 20. More specifically, the vertical position of the upper surface of the upper wall portion 53 may be substantially the same as the vertical position of the upper surface of the floor cross member 23. In addition, the vertical position of the lower surface of the upper wall portion 53 may be substantially the same as the vertical position of the lower surface of the floor cross member 23. In addition, the vertical position of the upper surface of the first inner vehicle transverse plate portion 561 may be substantially the same as the vertical position of the upper surface of the floor cross member 23. In addition, the vertical position of the lower surface of the first inner vehicle transverse plate portion 561 may be substantially the same as the vertical position of the lower surface of the floor cross member 23. Further, the upper wall portion 53 may be disposed at a vertical position substantially the same as the upper surface of the floor cross member 23 when viewed in the vehicle width direction or the longitudinal direction, and the first inner vehicle transverse plate portion 561 may be disposed at a vertical position substantially the same as the lower surface of the floor cross member 23 when viewed in the vehicle width direction.

[0081] The lower wall portion 54 and the second inner vehicle side transverse plate portion 562 are disposed at positions overlapping the battery cross member 15 when viewed in the vehicle width direction in a state where the battery box 10 is mounted on the vehicle body bottom portion 20 of the vehicle. In other words, the lower wall portion 54 and the second inner vehicle side transverse plate portion 562 are positioned below the upper surface of the battery cross member 15 and above the lower surface of the battery cross member 15 in the vertical direction in a state where the battery box 10 is mounted on the vehicle body bottom portion 20 of the vehicle. Specifically, the vertical position of the upper surface of the second inner vehicle side transverse plate portion 562 may be substantially the same as the vertical position of the upper surface of the battery cross member 15. In addition, the vertical position of the lower surface of the second inner vehicle side transverse plate portion 562 may be substantially the same as the vertical position of the lower surface of the battery cross member 15. In addition, the vertical position of the upper surface of the lower wall portion 54 may be substantially the same as the vertical position of the upper surface of the portion (cap-shaped flange portion) of the battery cross member 15 that is joined to the upper surface of the lower panel 11. In addition, the vertical position of the lower surface of the lower wall portion 54 may be substantially the same as the vertical position of the lower surface of the battery cross member 15. Further, in the present embodiment, since the upper surface of the battery cross member 15 is positioned below the lower surface of the floor cross member 23, the second inner vehicle side transverse plate portion 562 is disposed below the first inner vehicle side transverse plate portion 561 (in other words, between the first inner vehicle side transverse plate portion 561 and the lower wall portion 54 in the vertical direction). Further, the lower wall portion 54 may be disposed such that its lower surface is positioned at substantially the same vertical position as the lower surface of the battery cross member 15 when viewed in the vehicle width direction or the front-rear direction, and the second inner vehicle side transverse plate portion 562 may be disposed such that its upper surface is at substantially the same vertical position as the upper surface of the battery cross member 15 when viewed in the vehicle width direction or the front-rear direction.

[0082] Inside the outer vehicle space 502, a plurality of outer vehicle side transverse plate portions 57 that connect the intermediate longitudinal plate portion 55 and the outer vehicle side wall portion 52 are provided. The plurality of outer vehicle side transverse plate portions 57 include a first outer vehicle side transverse plate portion 571, a second outer vehicle side transverse plate portion 572, a third outer vehicle side transverse plate portion 573, a fourth outer vehicle side transverse plate portion 574, and a fifth outer vehicle side transverse plate portion 575. The first outer vehicle side transverse plate portion 571 is a plate-shaped portion that extends substantially horizontally. The second outer vehicle side transverse plate portion 572, the third outer vehicle side transverse plate portion 573, the fourth outer vehicle side transverse plate portion 574, and the fifth outer vehicle side transverse plate portion 575 are each plate-shaped portions that extend in a direction inclined in the vertical direction and the vehicle width direction when viewed in the front-rear direction.

[0083] The part where the inner ends of the outer side horizontal plate part 571 of the first vehicle and the outer side horizontal plate part 572 of the second vehicle are joined to the middle vertical plate part 55 is joined to the part where the inner side horizontal plate part 561 of the first vehicle is located (the part where the middle vertical plate part 55 intersects with the inner side horizontal plate part 561 of the first vehicle). Since both the outer side horizontal plate part 571 of the first vehicle and the inner side horizontal plate part 561 of the first vehicle are plate-like members extending substantially horizontally, the outer side horizontal plate part 571 of the first vehicle and the inner side horizontal plate part 561 of the first vehicle are disposed at the same vertical position. The part where the inner ends of the outer side horizontal plate part 573 of the third vehicle and the outer side horizontal plate part 574 of the fourth vehicle are joined to the middle vertical plate part 55 is joined to the part where the inner side horizontal plate part 562 of the second vehicle is located. The part where the inner end of the outer side horizontal plate part 575 of the fifth vehicle is joined to the middle vertical plate part 55 is joined to the part where the lower wall part 54 is located. The outer end of the outer side horizontal plate part 571 of the first vehicle is joined to the outer side wall part 52. In this way, the inner ends of the plurality of outer side horizontal plate parts 57 are joined to either the inner side lower wall part 541 or the outer ends of the plurality of inner side horizontal plate parts 56.

[0084] The outer ends of the outer side horizontal plate part 572 of the second vehicle and the outer side horizontal plate part 573 of the third vehicle are joined to substantially the same part of the outer side wall part 52. In other words, the outer end of the outer side horizontal plate part 572 of the second vehicle is joined to the outer end of the outer side horizontal plate part 573 of the third vehicle. The vertical position of the part where the outer end of the outer side horizontal plate part 572 of the second vehicle is joined to the outer side wall part 52 is lower than the vertical position of the part where the inner end of the outer side horizontal plate part 572 of the second vehicle is joined to the middle vertical plate part 55. Therefore, the outer side horizontal plate part 572 of the second vehicle is inclined in such a way that the vertical position becomes higher as it goes from the outer side of the vehicle toward the inner side of the vehicle. On the other hand, the vertical position of the part where the outer end of the outer side horizontal plate part 573 of the third vehicle is joined to the outer side wall part 52 is higher than the vertical position of the part where the inner end of the outer side horizontal plate part 573 of the third vehicle is joined to the middle vertical plate part 55. Therefore, the outer side horizontal plate part 573 of the third vehicle is inclined in such a way that the vertical position becomes lower as it goes from the outer side of the vehicle toward the inner side of the vehicle.

[0085] The outer end portions of the outer lateral plate portion 574 of the fourth vehicle and the outer lateral plate portion 575 of the fifth vehicle on the vehicle outer side are joined to substantially the same position of the vehicle outer side wall portion 52. In other words, the outer end portion of the outer lateral plate portion 574 of the fourth vehicle on the vehicle outer side is joined to the outer end portion of the outer lateral plate portion 575 of the fifth vehicle on the vehicle outer side. Further, the vertical position of the portion where the outer end portion of the outer lateral plate portion 574 of the fourth vehicle on the vehicle outer side is joined to the vehicle outer side wall portion 52 is lower than the vertical position of the portion where the inner end portion of the outer lateral plate portion 574 of the fourth vehicle on the vehicle inner side is joined to the intermediate longitudinal plate portion 55. Therefore, the outer lateral plate portion 574 of the fourth vehicle is inclined such that the vertical position becomes higher as it goes from the vehicle outer side toward the vehicle inner side. On the other hand, the vertical position of the portion where the outer end portion of the outer lateral plate portion 575 of the fifth vehicle on the vehicle outer side is joined to the vehicle outer side wall portion 52 is higher than the vertical position of the portion where the inner end portion of the outer lateral plate portion 575 of the fifth vehicle on the vehicle inner side is joined to the intermediate longitudinal plate portion 55. Therefore, the outer lateral plate portion 575 of the fifth vehicle is inclined such that the vertical position becomes lower as it goes from the vehicle outer side toward the vehicle inner side.

[0086] In addition, it can be said that "the second outer lateral plate portion 572, the third outer lateral plate portion 573, and the intermediate longitudinal plate portion 55 (more precisely, the portion between the first inner lateral plate portion 561 and the second inner lateral plate portion 562 in the intermediate longitudinal plate portion 55) are arranged to form a substantially triangular shape when viewed in the front-rear direction". In this case, the intermediate longitudinal plate portion 55 corresponds to the base of the triangle, and the joining portion of the second outer lateral plate portion 572 and the third outer lateral plate portion 573 corresponds to the apex of the triangle. And the apex of the triangle is joined to the vehicle outer side wall portion 52. Similarly, it can be said that "the fourth outer lateral plate portion 574, the fifth outer lateral plate portion 575, and the intermediate longitudinal plate portion 55 (more precisely, the portion between the first inner lateral plate portion 561 and the second inner lateral plate portion 562 in the intermediate longitudinal plate portion 55) are arranged to form a substantially triangular shape when viewed in the front-rear direction". In this case, the intermediate longitudinal plate portion 55 corresponds to the base of the triangle, and the joining portion of the fourth outer lateral plate portion 574 and the fifth outer lateral plate portion 575 corresponds to the apex of the triangle. And the apex of the triangle is joined to the vehicle outer side wall portion 52. Thus, the vehicle outer side wall portion 52, the intermediate longitudinal plate portion 55, and the plurality of outer lateral plate portions 57 constitute a truss structure when viewed in the front-rear direction.

[0087] Further, the upper inner wall portion 531, the lower inner wall portion 541, and the plurality of inner lateral plate portions 56 (the first inner lateral plate portion 561 and the second inner lateral plate portion 562) of the vehicle form an inner vehicle energy absorption portion 401. In addition, the upper outer wall portion 532, the lower outer wall portion 542, and the plurality of outer lateral plate portions 57 (the first outer lateral plate portion 571, the second outer lateral plate portion 572, the third outer lateral plate portion 573, the fourth outer lateral plate portion 574, and the fifth outer lateral plate portion 575) of the vehicle form an outer vehicle energy absorption portion 402. Thus, in the present embodiment, the portion of the lower side member structural component 12 that is closer to the outer side of the vehicle than the intermediate longitudinal plate portion 55 forms the outer vehicle energy absorption portion 402, and the portion closer to the inner side of the vehicle than the intermediate longitudinal plate portion 55 forms the inner vehicle energy absorption portion 401. In other words, the lower side member structural component 12 includes two energy absorption portions 401 and 402 arranged in the vehicle width direction.

[0088] The outer vehicle energy absorption portion 402 and the inner vehicle energy absorption portion 401 are configured to absorb the energy of the impact load generated by the side collision or the like by compressing and deforming in the vehicle width direction when the vehicle undergoes a side collision or the like. In the present embodiment, the outer vehicle energy absorption portion 402 is configured to be more difficult to compress and deform in the vehicle width direction than the inner vehicle energy absorption portion 401 (higher rigidity against compression deformation in the vehicle width direction). Specifically, the number of the plurality of outer lateral plate portions 57 included in the outer vehicle energy absorption portion 402 is larger than the number of the plurality of inner lateral plate portions 56 included in the inner vehicle energy absorption portion 401. According to such a structure, the outer vehicle energy absorption portion 402 is more difficult to compress and deform in the vehicle width direction than the inner vehicle energy absorption portion 401. In addition, it can also be said that "the density of the material forming the outer vehicle energy absorption portion 402 is higher than the density of the material forming the inner vehicle energy absorption portion 401".

[0089] Thus, the lower side member structural component 12 includes the outer vehicle energy absorption portion 402 and the inner vehicle energy absorption portion 401 configured to absorb energy by compression deformation. According to such a structure, when a load is applied to the vehicle equipped with the battery box 10 from the outer side of the vehicle toward the inner side, the load is absorbed by the outer vehicle energy absorption portion 402 and the inner vehicle energy absorption portion 401 of the lower side member structural component 12 of the battery box 10.

[0090] Further, the outer vehicle body side energy absorption portion 402 (in other words, the portion of the lower side beam structural member 12 that is closer to the outer side of the vehicle than the intermediate longitudinal plate portion 55) is configured to be less deformable than the inner vehicle body side energy absorption portion 401 (the portion of the lower side beam structural member 12 that is closer to the inner side of the vehicle than the intermediate longitudinal plate portion 55). With such a structure, compared with a structure in which the outer side portion of the lower side beam structural member 12 is more deformable than the inner side portion, the amount of energy that can be absorbed can be increased. That is, in a structure in which the outer vehicle body side energy absorption portion 402 of the lower side beam structural member 12 is more deformable than the inner vehicle body side energy absorption portion 401, when an object collides with the outer side surface of the lower side beam structural member 12 of the vehicle, only the portion of the outer vehicle body side energy absorption portion 402 that is hit by the object deforms. In contrast, according to the present embodiment, when an object collides with the outer side surface of the lower side beam structural member 12 of the vehicle, first, the inner vehicle body side energy absorption portion 401 is pressed inward by the outer vehicle body side energy absorption portion 402 without being compressed and deformed, so that the inner vehicle body side energy absorption portion 401 is compressed and deformed before the outer vehicle body side energy absorption portion 402.

[0091] Moreover, when the inner vehicle body side energy absorption portion 401 starts to deform, the outer vehicle body side energy absorption portion 402 is not deformed. Therefore, the load acting on the non-deformed outer vehicle body side energy absorption portion 402 is dispersed over the entire inner vehicle body side energy absorption portion 401 (substantially the entire length in the front-rear direction). Accordingly, the load is also transmitted to the inner vehicle body side energy absorption portion 401 over a wide range, and a wide range of the inner vehicle body side energy absorption portion 401 deforms. The greater the amount of deformation of the lower side beam structural member 12, the greater the amount of energy absorbed by the lower side beam structural member 12. Therefore, if the range of deformation of the inner vehicle body side energy absorption portion 401 becomes larger (expands in the front-rear direction), the amount of energy absorption increases. That is, the battery box 10 can efficiently absorb the load using a larger range of the inner vehicle body side energy absorption portion 401.

[0092] In addition, the ratio of the vehicle width direction dimension of the outer vehicle body side energy absorption portion 402 to that of the inner vehicle body side energy absorption portion 401 is not particularly limited, but it is more preferable that the vehicle width direction dimension of the inner vehicle body side energy absorption portion 401 is larger. The reason is that the larger the amount of compressive deformation of the inner vehicle body side energy absorption portion 401, the greater the amount of energy that can be absorbed.

[0093] In addition, the inner ends of the outer lateral plate portions 571 of the first vehicle and the outer lateral plate portions 572 of the second vehicle are joined to the joint portion of the intermediate longitudinal plate portion 55 that is joined to the inner lateral plate portion 561 of the first vehicle. The inner ends of the outer lateral plate portions 573 of the third vehicle and the outer lateral plate portions 574 of the fourth vehicle are joined to the joint portion of the intermediate longitudinal plate portion 55 that is joined to the inner lateral plate portion 562 of the second vehicle. The inner ends of the outer lateral plate portion 575 of the fifth vehicle and the inner lower wall portion 541 are joined to the lower end portion of the intermediate longitudinal plate portion 55 and near the joint portion of the intermediate longitudinal plate portion 55 that is joined to the inner lower wall portion 541. With such a structure, the load applied to the outer vehicle wall portion 52 is transmitted to the inner upper wall portion 531 through the outer upper wall portion 532 of the vehicle, transmitted to the inner lateral plate portion 561 of the first vehicle through the outer lateral plate portion 571 of the first vehicle and the outer lateral plate portion 572 of the second vehicle, transmitted to the inner lateral plate portion 562 of the second vehicle through the outer lateral plate portion 573 of the third vehicle and the outer lateral plate portion 574 of the fourth vehicle, and transmitted to the inner lower wall portion 541 through the outer lateral plate portion 575 of the fifth vehicle and the outer lower wall portion 542. Thus, the loads applied to the plurality of outer lateral plate portions 57 can be reliably transmitted to either the inner lower wall portion 541 or any of the plurality of inner lateral plate portions 56.

[0094] Moreover, the inner upper wall portion 531 of the vehicle and the inner lateral plate portion 561 of the first vehicle are disposed at positions overlapping the floor cross member 23 when viewed in the vehicle width direction, and the inner lateral plate portion 562 of the second vehicle and the inner lower wall portion 541 are disposed at positions overlapping the battery cross member 15 when viewed in the vehicle width direction. Therefore, the loads applied to the inner upper wall portion 531 of the vehicle and the inner lateral plate portion 561 of the first vehicle are directly transmitted to the floor cross member 23. In addition, the loads applied to the inner lateral plate portion 562 of the second vehicle and the inner lower wall portion 541 are directly transmitted to the battery cross member 15. In other words, the loads applied to the side sill structure member 12 are borne by the floor cross member 23 and the battery cross member 15. Furthermore, such a structure can also be said to be "loads not completely absorbed by the outer vehicle energy absorption portion 402 and the inner vehicle energy absorption portion 401 are dispersed in the path transmitted in the floor cross member 23 and the path transmitted in the battery cross member 15".

[0095] In this way, the inner vehicle energy absorption portion 401 includes a first load transmission portion that transmits the load applied from the outside of the vehicle to the floor cross member 23 and a second load transmission portion that transmits the load applied from the outside of the vehicle to the battery cross member 15. Specifically, the inner vehicle energy absorption portion 401 includes the inner upper wall portion 531 and the inner lateral plate portion 561 disposed at positions overlapping the floor cross member 23 when viewed in the vehicle width direction as the first load transmission portion, and the inner vehicle energy absorption portion 401 includes the inner lateral plate portion 562 and the inner lower wall portion 541 disposed at positions overlapping the battery cross member 15 when viewed in the vehicle width direction as the second load transmission portion.

[0096] Moreover, since the floor crossmember 23 and the battery crossmember 15 bear loads, the "deformation like entering the vehicle interior" of the lower side beam structural member 12 is prevented or suppressed. Therefore, in the case of a side collision or the like, the effect of preventing damage to the battery housed in the battery box 10 (specifically, damage to the battery caused by contact between the deformed lower side beam structural member 12 and the battery) can be improved. Therefore, compared with the case where the load transfer path is one, for example, the case where the transfer path is only the path transferred in the floor crossmember 23, the load transferred to the floor crossmember 23 and the battery crossmember 15 can be increased within the range where the deformation of the battery box 10 can be suppressed.

[0097] Therefore, even if the energy absorption amount of the lower side beam structural member 12 is reduced, the deformation of the battery box 10 can be suppressed. That is, the lower side beam structural member 12 can be formed compactly. Therefore, the widthwise dimension of the lower side beam structural member 12 can be reduced. As a result, the internal space of the battery box 10 (in other words, the placement surface 111 of the lower panel 11) can be expanded in the vehicle width direction. And by mounting more batteries in the expanded internal space, the cruising range of the vehicle can be further improved.

[0098] In addition, if the structure is such that the battery box 10 functions as a lower side beam as in the present embodiment, the vehicle body bottom 20 of the vehicle does not require a lower side beam or a strength member having the function of a lower side beam (a strength member different from the lower side beam). Therefore, the space for mounting batteries can be increased by the amount of the lower side beam and the strength member different from the lower side beam. Therefore, while ensuring the rigidity of the vehicle body bottom 20 of the vehicle (without reducing the strength of the vehicle body bottom 20 of the vehicle), the batteries that can be mounted can be increased.

[0099] In addition, according to the battery box 10 according to the present embodiment, since the lower side beam structural member 12 is provided with the energy absorption portions 401 and 402, there is no need to secure a space for disposing the energy absorption portions 401 and 402 outside the lower side beam structural member 12, and the internal space of the battery box 10 (the placement surface 111 of the lower panel 11) can be further expanded by this space amount.

[0100] In addition, in the above embodiment, an example is shown in which the upper surface of the floor crossmember 23 is located above the upper surfaces of the upper wall portions 53 of the pair of left and right lower side beam structural members 12, but the structure is not limited to this. Figure 7 It is a cross-sectional view showing the structure of the vehicle body bottom 20 and the lower side beam structural member 12 according to the modified example. As Figure 7 shown, the vertical position of the upper surface of the floor crossmember 23 may be substantially the same as the vertical position of the upper surfaces of the upper wall portions 53 of the pair of left and right lower side beam structural members 12.

[0101] In addition, in the above-described embodiment, a structure is shown in which the end portions in the longitudinal direction of the plurality of battery cross members 15 are joined to the inner side surfaces of the left and right pair of lower side beam structural members 12 via mounting metal fittings 17, but the structure is not limited to this. In short, the end portions in the longitudinal direction of the plurality of battery cross members 15 may be joined in such a manner as to be able to withstand the vehicle width direction loads transmitted from the left and right pair of lower side beam structural members 12, respectively. For example, as Figure 7 shown, the end portions in the longitudinal direction of the plurality of battery cross members 15 may also be joined to the inner side surfaces of the left and right pair of lower side beam structural members 12 in a directly contacting manner. In this case, joining of the battery cross members 15 and the left and right pair of lower side beam structural members 12 can employ, for example, welding.

[0102] In addition, in the above-described embodiment, the floor cross member 23 is a component for mounting a seat, but the floor cross member 23 is not limited to such a component. The floor cross member 23 only needs to be a component having a long strip shape extending in the vehicle width direction, joined to the upper surface of the center floor panel 22, and configured to be able to withstand the vehicle width direction forces applied to the vehicle body bottom 20.

[0103] (Summary of the Embodiment)

[0104] The vehicle battery box 10 according to the present embodiment houses a drive battery that supplies power to a drive source of the vehicle. The vehicle battery box 10 includes: a plate-shaped lower panel 11 that is disposed substantially horizontally below the floor panel (center floor panel 22) of the vehicle body, and on which the drive battery is placed on the upper surface; a pair of lower side beam structural members 12 that are configured to be joined to both side ends in the vehicle width direction of the lower panel 11 and extend along the vehicle front-rear direction in a tubular shape, and are provided with energy absorption portions 401, 402 configured to be able to absorb the energy of the loads acting in the vehicle width direction; and battery cross members 15 that are disposed on the upper surface of the lower panel 11, extend in the vehicle width direction, and the both ends in the vehicle width direction are respectively joined to the inner side surfaces in the vehicle width direction of the pair of lower side beam structural members 12. And the energy absorption portions 401, 402 include: a first load transfer portion (inner side upper wall portion 531 and first inner side horizontal plate portion 561) that is disposed at a position overlapping with a floor cross member 23 provided on the floor panel (center floor panel 22) and extending in the vehicle width direction when viewed from the vehicle width direction; a second load transfer portion (second inner side horizontal plate portion 562 and inner side lower wall portion 541) that is disposed at a position overlapping with the battery cross member 15 when viewed from the vehicle width direction.

[0105] According to the present embodiment, by providing the lower side beam structural member 12 having the above-described structure in the vehicle battery box 10, even if the side frames of the vehicle battery box 10 are removed, deformation of the battery accommodation space caused by loads from the outside in the vehicle width direction can be prevented or suppressed, and the space for accommodating the battery can be expanded in the vehicle width direction by removing the side frames of the vehicle battery box 10. Further, in the present embodiment, it can be said that "the pair of lower side beam structural members 12 also serve as the side frames of the vehicle battery box 10".

[0106] Specifically, the lower side beam structural member 12 includes energy absorption portions 401 and 402. The energy absorption portion 401 includes a first load transfer portion (the vehicle inner upper wall portion 531 and the first vehicle inner horizontal plate portion 561) and a second load transfer portion (the second vehicle inner horizontal plate portion 562 and the vehicle inner lower wall portion 541). Thus, when a load (for example, an impact load generated due to a side collision) is applied to the vehicle on which the vehicle battery box 10 according to the present embodiment is mounted from the outside in the vehicle width direction, the load is absorbed by the energy absorption portions 401 and 402 of the lower side beam structural member 12 of the vehicle battery box 10.

[0107] Moreover, the first load transfer portion (the vehicle inner upper wall portion 531 and the first vehicle inner horizontal plate portion 561) and the second load transfer portion (the second vehicle inner horizontal plate portion 562 and the vehicle inner lower wall portion 541) are arranged so as to overlap with the floor cross member 23 and the battery cross member 15, respectively, when viewed from the vehicle width direction. Thus, the load not completely absorbed by the energy absorption portions 401 and 402 is dispersed to the path from the first load transfer portion (the vehicle inner upper wall portion 531 and the first vehicle inner horizontal plate portion 561) to the floor cross member 23 and the path from the second load transfer portion (the second vehicle inner horizontal plate portion 562 and the vehicle inner lower wall portion 541) to the battery cross member 15. Therefore, compared with the case where the load transfer path is one, the load transferred to the floor cross member 23 and the battery cross member 15 can be increased within a range where deformation of the vehicle battery box 10 can be suppressed. Accordingly, deformation of the battery accommodation space caused by loads from the outside in the vehicle width direction can be prevented or suppressed.

[0108] In addition, in the case of a structure in which there are two paths for transmitting loads, compared with a structure in which there is one path, even if the energy absorption amounts of the energy absorption portions 401 and 402 of the lower side beam structural member 12 are reduced, deformation of the vehicle battery box 10 can be suppressed. That is, the energy absorption portions 401 and 402 can be formed compactly. By forming the energy absorption portions 401 and 402 compactly, the dimension of the lower side beam structural member 12 in the vehicle width direction can be reduced. In addition, according to the vehicle battery box 10 according to the present embodiment, since the energy absorption portions 401 and 402 are provided in the lower side beam structural member 12, there is no need to secure a space for disposing the energy absorption portions 401 and 402 outside the lower side beam structural member 12, and the accommodation space for the drive battery on the lower panel 11 can be further enlarged by this space amount. As a result, the mounting amount of the drive battery can be increased.

[0109] Moreover, according to the present embodiment, a pair of cylindrical lower side beam structural members 12 provided at both side ends in the vehicle width direction of the lower panel 11 also serve as side frames of the vehicle battery box 10. In other words, the side frames of the vehicle battery box 10 are constituted by the lower side beams. Therefore, compared with a structure in which the lower side beams and the side frames are arranged side by side in the vehicle width direction, there is no need to secure a space for disposing the side frames, and thus the accommodation space for the drive battery on the lower panel 11 can be enlarged in the vehicle width direction. As a result, the mounting amount of the drive battery can be increased. As a result, the cruising range of a vehicle powered by electric power supplied from the drive battery can be further improved. As a result, the accommodation space for the drive battery on the lower panel 11 in the vehicle width direction can be further enlarged, and by mounting more drive batteries in the enlarged accommodation space, the cruising range of the vehicle can be further improved.

[0110] In addition, it can also be configured as follows: The pair of lower side beam structural members 12 include an outer frame portion 50, the outer frame portion 50 includes an inner vehicle side wall portion 51 located on the inner side in the vehicle width direction and an outer vehicle side wall portion 52 located on the outer side in the vehicle width direction with respect to the inner vehicle side wall portion 51, and the outer frame portion 50 extends in a cylindrical shape in the vehicle front-rear direction. The first load transmission portion (the inner vehicle upper wall portion 531 and the first inner vehicle transverse plate portion 561) and the second load transmission portion (the second inner vehicle transverse plate portion 562 and the inner vehicle lower wall portion 541) have plate-shaped portions extending in the vehicle front-rear direction and the vehicle width direction, and the inner ends in the vehicle width direction of the plate-shaped portions of the first load transmission portion (the inner vehicle upper wall portion 531 and the first inner vehicle transverse plate portion 561) and the second load transmission portion (the second inner vehicle transverse plate portion 562 and the inner vehicle lower wall portion 541) are joined to the inner vehicle side wall portion 51.

[0111] Thus, when a load is applied to the outer surface in the vehicle width direction of the lower side beam structural member 12 (in other words, the vehicle outer side wall portion 52) toward the inner side in the vehicle width direction, the load can be transmitted to the floor cross member 23 via the first load transmission portion (the vehicle inner upper wall portion 531 and the first vehicle inner horizontal plate portion 561) and the inner surface in the vehicle width direction of the lower side beam structural member 12 (in other words, the vehicle inner side wall portion 51), and the load can be transmitted to the battery cross member 15 via the second load transmission portion (the second vehicle inner horizontal plate portion 562 and the vehicle inner lower wall portion 541) and the inner surface in the vehicle width direction of the lower side beam structural member 12.

[0112] It can also be configured such that the vertical position of the upper surface of the first load transmission portion (the vehicle inner upper wall portion 531 and the first vehicle inner horizontal plate portion 561) is substantially the same as the vertical position of the upper surface of the floor cross member 23. In addition, it can also be configured such that the vertical position of the lower surface of the first load transmission portion (the vehicle inner upper wall portion 531 and the first vehicle inner horizontal plate portion 561) is substantially the same as the vertical position of the lower surface of the floor cross member 23. In addition, it can also be configured such that the vertical position of the upper surface of the second load transmission portion (the second vehicle inner horizontal plate portion 562 and the vehicle inner lower wall portion 541) is substantially the same as the vertical position of the upper surface of the battery cross member 15. In addition, it can also be configured such that the vertical position of the lower surface of the second load transmission portion (the second vehicle inner horizontal plate portion 562 and the vehicle inner lower wall portion 541) is substantially the same as the vertical position of the lower surface of the battery cross member 15.

[0113] Thus, the load can be reliably transmitted from the first load transmission portion (the vehicle inner upper wall portion 531 and the first vehicle inner horizontal plate portion 561) to the floor cross member 23. Similarly, the load can be reliably transmitted from the second load transmission portion (the second vehicle inner horizontal plate portion 562 and the vehicle inner lower wall portion 541) to the battery cross member 15.

[0114] In addition, it can also be configured as follows: the pair of lower side beam structural members 12 has a plate-shaped intermediate longitudinal plate portion 55, which is formed inside the outer frame portion 50 between the vehicle inner side wall portion 51 and the vehicle outer side wall portion 52, and extends in the vehicle front-rear direction and the vertical direction, and the outer ends in the vehicle width direction of the plate-shaped portions of the first load transmission portion (the vehicle inner upper wall portion 531 and the first vehicle inner horizontal plate portion 561) and the second load transmission portion (the second vehicle inner horizontal plate portion 562 and the vehicle inner lower wall portion 541) are joined to the intermediate longitudinal plate portion 55.

[0115] In this case, it is also possible to configure such that a plurality of vehicle outer side cross plates 57 are provided between the intermediate longitudinal plate portion 55 and the vehicle outer side wall portion 52. The outer ends in the vehicle width direction of the plurality of vehicle outer side cross plates 57 are joined to the vehicle outer side wall portion 52, and the inner ends in the vehicle width direction are joined to the joining portion of the intermediate longitudinal plate portion 55 and the first load transfer portion (the vehicle inner upper wall portion 531 and the first vehicle inner side cross plate portion 561) or the joining portion of the intermediate longitudinal plate portion 55 and the second load transfer portion (the second vehicle inner side cross plate portion 562 and the vehicle inner lower wall portion 541).

[0116] Moreover, in this case, it is also possible to configure such that the plurality of vehicle outer side cross plates 57 are configured as plate-like members that extend in the vehicle longitudinal direction and also extend in a direction inclined with respect to the vertical direction and the vehicle width direction.

[0117] Accordingly, when a load acting inward in the vehicle width direction is applied to the outer surface in the vehicle width direction of the lower side member structural component 12 (in other words, the vehicle outer side wall portion 52), the load can be transmitted to the first load transfer portion (the vehicle inner upper wall portion 531 and the first vehicle inner side cross plate portion 561) and the second load transfer portion (the second vehicle inner side cross plate portion 562 and the vehicle inner lower wall portion 541) via the plurality of vehicle outer side cross plates 57 respectively.

[0118] It is also possible to configure such that a pair of lower side member structural components 12 are joined to the vehicle body front structure (a pair of left and right torsion boxes 25, a pair of left and right front side members 26, and a front bumper reinforcement 27) that forms the front portion of the vehicle body at the front end portions, and a pair of lower side member structural components 12 are joined to the vehicle body rear structure (a pair of left and right rear side members 28 and a rear floor panel 29) that forms the rear portion of the vehicle body at the rear end portions.

[0119] Thereby, the pair of lower side member structural components 12 function as the lower side members of the vehicle.

[0120] In this case, it is also possible to configure such that the front end portions of the pair of lower side member structural components 12 are respectively joined to the strength components (a pair of left and right torsion boxes 25) that bear the impact load acting from the front among the vehicle body front structure (a pair of left and right torsion boxes 25, a pair of left and right front side members 26, and a front bumper reinforcement 27), and the rear end portions of the pair of lower side member structural components 12 are respectively joined to the strength components (a pair of left and right rear side members 28) that bear the impact load acting from the rear among the vehicle body rear structure (a pair of left and right rear side members 28 and a rear floor panel 29).

[0121] Accordingly, the impact load acting from the front of the vehicle is transmitted to the pair of lower side member structural components 12 via the front body structure (a pair of left and right torsion boxes 25, a pair of left and right front side members 26, and a front bumper reinforcement 27), and the impact load acting from the rear of the vehicle is transmitted to the pair of lower side member structural components 12 via the rear body structure (a pair of left and right rear side members 28 and a rear floor panel 29). By transmitting the impact loads from the front and rear to the pair of lower side member structural components 12 in this way, it is possible to protect the battery on the lower panel 11 provided between the pair of lower side member structural components 12 from the impact loads from the front and rear.

[0122] It can be said that the front body structure (a pair of left and right torsion boxes 25, a pair of left and right front side members 26, and a front bumper reinforcement 27) and the rear body structure (a pair of left and right rear side members 28 and a rear floor panel 29) are connected by the lower side member skin member 21, and the lower side member skin member 21 is configured to be able to cover the pair of lower side member structural components 12 from above respectively.

[0123] Accordingly, by covering the pair of lower side member structural components 12 from above respectively with the lower side member skin member 21 that connects the front body structure (a pair of left and right torsion boxes 25, a pair of left and right front side members 26, and a front bumper reinforcement 27) and the rear body structure (a pair of left and right rear side members 28 and a rear floor panel 29), it is possible to form the lower side member skin member 21 and the lower side member structural components 12 from different metals. Therefore, for example, the lower side member skin member 21 can be formed of a steel plate, and the lower side member structural components 12 can be formed of aluminum or an aluminum alloy. By configuring in this way, for example, body parts such as pillars can be welded to the lower side member skin member 21, and in addition, the lower side member structural components 12 can be formed of aluminum or the like to achieve weight reduction of the vehicle battery box 10.

[0124] The vehicle battery box 10 according to the present embodiment houses a drive battery that supplies power to the drive source of the vehicle. The vehicle battery box 10 includes: a plate-shaped lower panel 11 that is disposed substantially horizontally below the floor panel (central floor panel 22) of the vehicle body, and a drive battery is placed on the upper surface of the lower panel 11; and a pair of lower side member structural components 12 that are respectively disposed at both ends in the vehicle width direction of the lower panel 11, and energy absorption portions 401 and 402 are provided that are configured to be able to absorb the load acting in the vehicle width direction. In addition, the energy absorption portions 401 and 402 include: an in-vehicle energy absorption portion 401; and an out-of-vehicle energy absorption portion 402, and the out-of-vehicle energy absorption portion 402 is joined to the in-vehicle energy absorption portion 401 and is formed on the outer side in the vehicle width direction compared to the in-vehicle energy absorption portion 401. Moreover, the out-of-vehicle energy absorption portion 402 is configured to be more difficult to deform than the above-mentioned in-vehicle energy absorption portion 401.

[0125] According to the present embodiment, among the energy absorption portions 401 and 402 provided in the lower side beam structural member, the vehicle outer side energy absorption portion 402 constituting the outer side in the vehicle width direction is configured to be less deformable than the vehicle inner side energy absorption portion 401 constituting the inner side in the vehicle width direction. Therefore, when a load (for example, an impact load generated by a side collision) is applied to the vehicle battery box 10 from the outer side in the vehicle width direction, the vehicle inner side energy absorption portion 401 is compressed and deformed in the vehicle width direction earlier than the vehicle outer side energy absorption portion 402. Here, when the vehicle inner side energy absorption portion 401 starts to deform, the vehicle outer side energy absorption portion 402 is in an undeformed or slightly deformed state. Therefore, the load acting on the vehicle outer side energy absorption portion 402 in the undeformed or slightly deformed state is dispersed over the entire range where the vehicle outer side energy absorption portion 402 is disposed. Since a relatively large range of the vehicle inner side energy absorption portion is compressed and deformed, the energy generated by the load is absorbed. In this way, the load is also transmitted to the vehicle inner side energy absorption portion 401 over a relatively large range, so that a larger range of the vehicle inner side energy absorption portion 401 can be used to efficiently absorb the load.

[0126] The energy that cannot be absorbed by the compression deformation of the vehicle inner side energy absorption portion 401 is absorbed by the compression deformation of the vehicle outer side energy absorption portion 402 and the deformation of the lower side beam structural member 12 entering the inner side in the vehicle width direction. However, according to the present embodiment, since the amount of energy absorbed by the vehicle inner side energy absorption portion 401 can be increased, the effect of preventing or suppressing the deformation of the lower side beam structural member 12 in the manner of entering the inner side in the vehicle width direction can be improved. Therefore, the effect of preventing or suppressing the situation where the lower side beam structural member 12 enters the space where the battery is placed and contacts the battery (in other words, the effect of protecting the battery) can be improved.

[0127] It can also be configured that the lower side beam structural member 12 includes: an outer frame portion 50 that extends in a cylindrical shape in the vehicle front-rear direction; and a plate-shaped intermediate longitudinal plate portion 55 that is formed inside the outer frame portion 50 and extends in the vehicle front-rear direction and the up-down direction. The outer frame portion 50 includes a vehicle inner side wall portion 51 located on the inner side in the vehicle width direction, a vehicle outer side wall portion 52 located on the outer side in the vehicle width direction with respect to the vehicle inner side wall portion 51, an upper wall portion 53 that joins the upper ends of the vehicle inner side wall portion 51 and the vehicle outer side wall portion 52, and a lower wall portion 54 that joins the lower ends of the vehicle inner side wall portion 51 and the vehicle outer side wall portion 52. The upper end of the intermediate longitudinal plate portion 55 is joined to the upper wall portion 53, and the lower end of the intermediate longitudinal plate portion 55 is joined to the lower wall portion 54. The space inside the outer frame portion 50 is divided by the intermediate longitudinal plate portion 55 into a vehicle inner side space 501 closer to the inner side in the vehicle width direction than the intermediate longitudinal plate portion 55 and a vehicle outer side space 502 closer to the outer side in the vehicle width direction than the intermediate longitudinal plate portion 55.

[0128] In this case, it is also possible to configure that the upper wall portion 53 includes an inner vehicle upper wall portion 531 and an outer vehicle upper wall portion 532. The inner vehicle upper wall portion 531 constitutes a portion closer to the inner side in the vehicle width direction than the joint position of the upper wall portion 53 and the intermediate longitudinal plate portion 55. The outer vehicle upper wall portion 532 constitutes a portion closer to the outer side in the vehicle width direction than the joint position of the upper wall portion 53 and the intermediate longitudinal plate portion 55. The lower wall portion 54 includes an inner vehicle lower wall portion 541 and an outer vehicle lower wall portion 542. The inner vehicle lower wall portion 541 constitutes a portion closer to the inner side in the vehicle width direction than the joint position of the lower wall portion 54 and the intermediate longitudinal plate portion 55. The outer vehicle lower wall portion 542 constitutes a portion closer to the outer side in the vehicle width direction than the joint position of the lower wall portion 54 and the intermediate longitudinal plate portion 55. In the inner vehicle space 501, a plurality of inner vehicle transverse plate portions 56 that join the intermediate longitudinal plate portion 55 and the inner vehicle wall portion 51 are formed. In the outer vehicle space 502, a plurality of outer vehicle transverse plate portions 57 that join the intermediate longitudinal plate portion 55 and the outer vehicle wall portion 52 are formed. The inner vehicle energy absorption portion 401 is constituted by the inner vehicle upper wall portion 531, the inner vehicle lower wall portion 541, and the plurality of inner vehicle transverse plate portions 56.

[0129] Moreover, in this case, it is also possible to configure that any one of the inner ends in the vehicle width direction of the plurality of outer vehicle transverse plate portions 57 is joined to any one of the outer ends in the vehicle width direction of the plurality of inner vehicle transverse plate portions 56.

[0130] Thereby, the load applied to each of the outer vehicle transverse plate portions 57 can be reliably transmitted to any one of the inner vehicle transverse plate portions 56.

[0131] It is also possible to configure that the inner vehicle energy absorption portion 401 is constituted by the inner vehicle upper wall portion 531, the inner vehicle lower wall portion 541, and the plurality of inner vehicle transverse plate portions 56, and the outer vehicle energy absorption portion 402 is constituted by the outer vehicle upper wall portion 532, the outer vehicle lower wall portion 542, and the plurality of outer vehicle transverse plate portions 57.

[0132] Accordingly, the inner vehicle energy absorption portion 401 can absorb energy by deforming the inner vehicle upper wall portion 531, the inner vehicle lower wall portion 541, and the plurality of inner vehicle transverse plate portions 56. In addition, the outer vehicle energy absorption portion 402 can absorb energy by deforming the outer vehicle upper wall portion 532, the outer vehicle lower wall portion 542, and the plurality of outer vehicle transverse plate portions 57.

[0133] It is also possible to configure that the vehicle width direction dimension of the inner vehicle energy absorption portion 401 is larger than the vehicle width direction dimension of the outer vehicle energy absorption portion 402.

[0134] Thereby, the amount of energy that can be absorbed by the compression deformation of the energy absorption portions 401 and 402 in the vehicle width direction can be increased.

[0135] It is also possible to configure such that the number of the plurality of vehicle outer side plate portions 57 is larger than the number of the plurality of vehicle inner side plate portions 56.

[0136] Accordingly, by making the number of the vehicle outer side plate portions 57 larger than the number of the vehicle inner side plate portions 56, the vehicle outer side energy absorption portion 402 can be configured to be less deformable than the vehicle inner side energy absorption portion 401.

[0137] The vehicle battery box 10 can also be configured to include a battery cross member 15. The battery cross member 15 is provided on the upper surface of the lower panel 11, extends in the vehicle width direction, and both ends in the vehicle width direction are respectively joined to a pair of the above-mentioned lower side beam structural members 12. At least a part (the second vehicle inner side plate portion 562) of the plurality of vehicle inner side plate portions 56 is provided at a position overlapping with the battery cross member 15 when viewed in the vehicle width direction.

[0138] Thereby, a load applied to the lower side beam structural member 12 from the outside in the vehicle width direction is received by the battery cross member 15 through the vehicle inner side plate portion 56 (the second vehicle inner side plate portion 562) overlapping with the battery cross member 15. Therefore, it is possible to prevent or suppress a situation where the lower side beam structural member 12 deforms in a manner of entering the vehicle inner side.

[0139] It is also possible to configure such that a pair of the lower side beam structural members 12 are joined to a vehicle front portion structure (a pair of left and right anti-torsion boxes 25, a pair of left and right front side members 26, and a front bumper reinforcement 27) constituting the front portion of the vehicle body at the front end, and a pair of the lower side beam structural members 12 are joined to a vehicle rear portion structure (a pair of left and right rear side members 28 and a rear floor panel 29) constituting the rear portion of the vehicle body at the rear end.

[0140] Accordingly, the lower side beam structural member 12 of the vehicle battery box 10 functions as the lower side beam of the vehicle body. That is, instead of the lower side beam integrally provided on the vehicle body in the past, the lower side beam structural member 12 functions as the lower side beam. In addition, since a pair of the lower side beam structural members 12 also serve as the side frames of the vehicle battery box 10, it is possible to remove the side frames of the vehicle battery box 10 (in other words, it is also possible not to provide side frames other than the lower side beam structural members 12). Therefore, it is possible to expand the accommodation space for the drive battery in the vehicle width direction while ensuring the strength of the vehicle body.

[0141] The vehicle battery box 10 according to this embodiment houses a driving battery that supplies power to a driving source of the vehicle. The vehicle battery box 10 includes: a plate-shaped bottom panel 11 that is disposed substantially horizontally below the floor panel (central floor panel 22) of the vehicle body, and on the upper surface of the bottom panel 11, the driving battery is placed; a pair of lower side beam structural members 12 that are configured to be tubular and extend along the vehicle front-rear direction by being respectively joined to both side ends in the vehicle width direction of the bottom panel 11, and at the front end sides of the pair of lower side beam structural members 12, they are joined to the vehicle body front structure (a pair of left and right torsion boxes 25, a pair of left and right front side members 26, and a front bumper reinforcement 27) that constitutes the front part of the vehicle body, and at the rear end sides of the pair of lower side beam structural members 12, they are joined to the vehicle body rear structure (a pair of left and right rear side members 28 and a rear floor panel 29) that constitutes the rear part of the vehicle body, and energy absorption parts 401, 402 that are configured to be able to absorb energy of a load acting in the vehicle width direction are provided inside the pair of lower side beam structural members 12; and a battery cross beam 15 that is disposed on the upper surface of the bottom panel 11, extends in the vehicle width direction, and both ends in the vehicle width direction are respectively joined to the inner surfaces in the vehicle width direction of the pair of lower side beam structural members 12.

[0142] According to this embodiment, a pair of tubular lower side beam structural members 12 provided at both side ends in the vehicle width direction of the bottom panel 11 are configured as the lower side beams of the vehicle body by being joined to the vehicle body front structure (a pair of left and right torsion boxes 25, a pair of left and right front side members 26, and a front bumper reinforcement 27) and the vehicle body rear structure (a pair of left and right rear side members 28 and a rear floor panel 29), and also serve as the side frames of the vehicle battery box 10. In other words, the lower side beams that are strength members of the vehicle body are constituted by the members (strength members of the vehicle battery box 10) that constitute the vehicle battery box 10. Therefore, compared with the structure in which the lower side beams and the side frames are arranged horizontally side by side in the vehicle width direction, the accommodation space for the driving battery inside the vehicle battery box 10 in the vehicle width direction is enlarged. As a result, the mounting amount of the driving battery can be increased, and as a result, the cruising range of the vehicle that obtains driving force from the driving source driven by the power supplied from the driving battery can be further improved.

[0143] The vehicle battery box 10 of the present embodiment can also be configured to include: a front frame 13 provided along the front end of the vehicle of the lower panel 11 and erected from the front end of the vehicle; and a rear frame 14 provided along the rear end of the vehicle of the lower panel 11 and erected from the rear end of the vehicle. The pair of lower side beam structural members 12 have a front protruding end portion 121 protruding forward compared to the front frame 13 and a rear protruding end portion 122 protruding rearward compared to the rear frame 14. The front protruding end portion 121 is joined to the front body structure (a pair of left and right torsion boxes 25, a pair of left and right front longitudinal beams 26, and a front bumper reinforcement 27), and the rear protruding end portion 122 is joined to the rear body structure (a pair of left and right rear longitudinal beams 28 and a rear floor panel 29).

[0144] Accordingly, by providing the front protruding end portion 121 and the rear protruding end portion 122 on the lower side beam structural member 12, the joint portions of the front body structure (a pair of left and right torsion boxes 25, a pair of left and right front longitudinal beams 26, and a front bumper reinforcement 27) and the rear body structure (a pair of left and right rear longitudinal beams 28 and a rear floor panel 29) with respect to the lower side beam structural member 12 can be increased compared to the structure without such provisions. Therefore, the mounting rigidity can be improved.

[0145] It can also be configured such that the front protruding end portion 121 and the rear protruding end portion 122 each have an outer side surface facing the outside in the vehicle width direction and an inner side surface facing the inside in the vehicle width direction, which are separately provided in the vehicle width direction. The front body structure (a pair of left and right torsion boxes 25, a pair of left and right front longitudinal beams 26, and a front bumper reinforcement 27) is joined to the outer side surface and the inner side surface of the front protruding end portion 121 of the pair of lower side beam structural members 12, and the rear body structure (a pair of left and right rear longitudinal beams 28 and a rear floor panel 29) is joined to the outer side surface and the inner side surface of the rear protruding end portion 122 of the pair of lower side beam structural members 12.

[0146] Accordingly, the front protruding end portion 121 and the rear protruding end portion 122 of the lower side beam structural member 12 can be joined to the vehicle body from the outside and the inside in the vehicle width direction, respectively. Therefore, compared to the structure in which the lower side beam structural member 12 is joined to the vehicle body from one side in the vehicle width direction (for example, only the outside), the mounting rigidity can be improved, and since the lower side beam structural member 12 is fixed from both sides in the vehicle width direction, the torsional rigidity of the lower side beam structural member 12 can also be improved.

[0147] It is also possible to configure such that the front protruding ends 121 of a pair of lower side beam structural members 12 are detachably joined to the front body structure (a pair of left and right torsion boxes 25, a pair of left and right front side members 26, and a front bumper reinforcement 27), and the rear protruding ends 122 of the pair of lower side beam structural members 12 are detachably joined to the rear body structure (a pair of left and right rear side members 28 and a rear floor panel 29).

[0148] In this case, it is also possible to adopt the following structure: The above-mentioned front body structure (a pair of left and right torsion boxes 25, a pair of left and right front side members 26, and a front bumper reinforcement 27) has an inner vehicle mounting wall portion 601 located on the inner side in the vehicle width direction of the above-mentioned front protruding end 121 and an outer vehicle mounting wall portion 602 located on the outer side in the vehicle width direction of the above-mentioned front protruding end 121. Moreover, the above-mentioned front protruding end 121 is detachably joined to the above-mentioned front body structure (a pair of left and right torsion boxes 25, a pair of left and right front side members 26, and a front bumper reinforcement 27) by a threaded member that penetrates the inner vehicle mounting wall portion 601 from the inner side in the vehicle width direction of the inner vehicle mounting wall portion 601 and is screwed to the inner side surface of the vehicle and a threaded member that penetrates the outer vehicle mounting wall portion 602 from the outer side in the vehicle width direction of the outer vehicle mounting wall portion 602 and is screwed to the outer side surface of the vehicle. In addition, the above-mentioned rear body structure (a pair of left and right rear side members 28 and a rear floor panel 29) has an inner vehicle mounting wall portion 601 located on the inner side in the vehicle width direction of the above-mentioned rear protruding end 122 and an outer vehicle mounting wall portion 602 located on the outer side in the vehicle width direction of the above-mentioned rear protruding end 122. Moreover, the above-mentioned rear protruding end 122 is detachably joined to the above-mentioned rear body structure (a pair of left and right rear side members 28 and a rear floor panel 29) by a threaded member that penetrates the inner vehicle mounting wall portion 601 from the inner side in the vehicle width direction of the inner vehicle mounting wall portion 601 and is screwed to the inner side surface of the vehicle and a threaded member that penetrates the outer vehicle mounting wall portion 602 from the outer side in the vehicle width direction of the outer vehicle mounting wall portion 602 and is screwed to the outer side surface of the vehicle.

[0149] Accordingly, the vehicle battery box 10 can be removed from the vehicle body, and the battery can be simply replaced, or the vehicle battery box 10 can be simply repaired.

[0150] The vehicle battery box 10 is detachably joined to the front body structure (a pair of left and right torsion boxes 25, a pair of left and right front side members 26, and a front bumper reinforcement 27). In addition, it is also possible to adopt the following structure: The above-mentioned rear body structure (a pair of left and right rear side members 28 and a rear floor panel 29) and the rear body structure (a pair of left and right rear side members 28 and a rear floor panel 29) are connected by a lower side beam skin member 21, and the lower side beam skin member 21 is configured to be able to cover a pair of lower side beam structural members 12 from above respectively.

[0151] Accordingly, the vehicle battery box 10 is detachably joined to the front body structure (a pair of left and right torsion boxes 25, a pair of left and right front side members 26, and a front bumper reinforcement 27). Further, by covering the pair of side sill structural members 12 from above with the side sill skin member 21 that connects the rear body structure (a pair of left and right rear side members 28 and a rear floor panel 29) to the rear body structure (a pair of left and right rear side members 28 and a rear floor panel 29), the side sill skin member 21 and the side sill structural members 12 can be made of different metals. Thus, for example, the side sill skin member 21 can be made of a steel plate, and the side sill structural members 12 can be made of aluminum or an aluminum alloy. By configuring in this way, for example, body parts such as pillars can be welded and joined to the side sill skin member 21, and the side sill structural members 12 can be made of aluminum or the like to achieve weight reduction of the vehicle battery box 10.

[0152] It is also possible to adopt the following structure: the front body structure (a pair of left and right torsion boxes 25, a pair of left and right front side members 26, and a front bumper reinforcement 27) includes a pair of left and right torsion boxes 25 as strength members that bear the load applied from the front of the vehicle, the rear body structure (a pair of left and right rear side members 28 and a rear floor panel 29) includes a pair of left and right rear side members 28 as strength members that bear the load applied from the rear of the vehicle, and the pair of side sill structural members 12 are respectively joined to the pair of left and right torsion boxes 25 at the front end portions and to the pair of left and right rear side members 28 at the rear end portions.

[0153] Accordingly, the load applied from the front of the vehicle is transmitted to the pair of side sill structural members 12 via the pair of left and right torsion boxes 25, and the load applied from the rear of the vehicle is transmitted to the pair of side sill structural members 12 via the pair of left and right rear side members 28. Moreover, the pair of side sill structural members 12 bear the load transmitted via the pair of left and right torsion boxes 25 and the load transmitted via the pair of left and right rear side members 28. In this way, the pair of side sill structural members 12 constitute the side sills of the vehicle.

[0154] The embodiments of the present invention have been described above, but the present invention is not limited to the above embodiments.

[0155] For example, the battery box 10 may further include a panel member (sometimes such a panel member is referred to as a shared panel) provided below the bottom panel 11. That is, the battery box 10 may have a double bottom structure.

[0156] In addition, the number of the inner vehicle side horizontal plate portion 56 and the outer vehicle side horizontal plate portion 57 of the lower side beam structural member 12 is not limited. Further, although a structure in which the temperature control fluid path accommodating portion 543 is provided in the lower side beam structural member 12 is shown, a structure in which the temperature control fluid path accommodating portion 543 is not provided may also be used. Further, in the above-described embodiment, in order to configure the outer vehicle side energy absorption portion 402 to be more difficult to compress and deform in the vehicle width direction than the inner vehicle side energy absorption portion 401, the number of the plurality of outer vehicle side horizontal plate portions 57 is made larger than the number of the plurality of inner vehicle side horizontal plate portions 56. Instead of or in addition to this, the thickness of the plurality of outer vehicle side horizontal plate portions 57 may be made thicker than the thickness of the plurality of inner vehicle side horizontal plate portions 56.

Claims

1. A battery box for a vehicle, which houses a driving battery that supplies power to a driving source of the vehicle. Among them, It includes: A plate-shaped bottom panel, which is disposed substantially horizontally below the floor panel of the vehicle body, and the driving battery is placed on the upper surface of the bottom panel; A pair of lower side beam structural members, which are configured as cylindrical shapes that are respectively joined to both ends in the vehicle width direction of the bottom panel and extend along the vehicle front-rear direction. An energy absorption portion configured to be able to absorb energy of a load acting in the vehicle width direction is provided on the pair of lower side beam structural members; and A battery cross beam, which is disposed on the upper surface of the bottom panel, extends in the vehicle width direction, and both ends in the vehicle width direction are respectively joined to the inner surfaces in the vehicle width direction of the pair of lower side beam structural members. The energy absorption portion includes: a first load transfer portion, which is disposed at a position that overlaps with a floor cross beam provided on the floor panel and extending in the vehicle width direction when viewed from the vehicle width direction; and a second load transfer portion, which is disposed at a position that overlaps with the battery cross beam when viewed from the vehicle width direction.

2. The battery box for a vehicle according to claim 1, Among them, The pair of lower side beam structural members include an outer frame portion, which includes an inner vehicle side wall portion located on the inner side in the vehicle width direction and an outer vehicle side wall portion located on the outer side in the vehicle width direction with respect to the inner vehicle side wall portion, and the outer frame portion extends in a cylindrical shape in the vehicle front-rear direction. The first load transfer portion and the second load transfer portion have plate-shaped portions that extend in the vehicle front-rear direction and the vehicle width direction. The inner ends in the vehicle width direction of the plate-shaped portions of the first load transfer portion and the second load transfer portion are joined to the inner vehicle side wall portion.

3. The battery box for a vehicle according to claim 2, Among them, The vertical position in the vertical direction of the upper surface of the first load transfer portion is substantially the same as the vertical position in the vertical direction of the upper surface of the floor cross beam.

4. The battery box for a vehicle according to claim 2, Among them, The vertical position in the vertical direction of the lower surface of the first load transfer portion is substantially the same as the vertical position in the vertical direction of the lower surface of the floor cross beam.

5. The battery box for a vehicle according to claim 2, Among them, The vertical position in the vertical direction of the upper surface of the second load transfer portion is substantially the same as the vertical position in the vertical direction of the upper surface of the battery cross beam.

6. The battery box for a vehicle according to claim 2, Among them, The vertical position in the vertical direction of the lower surface of the second load transfer portion is substantially the same as the vertical position in the vertical direction of the lower surface of the battery cross beam.

7. The battery box for a vehicle according to claim 2, Among them, The pair of lower side beam structural members have a plate-shaped intermediate longitudinal plate portion, which is formed inside the outer frame portion and between the inner vehicle side wall portion and the outer vehicle side wall portion, and extends in the vehicle front-rear direction and the vertical direction. The outer ends in the vehicle width direction of the plate-shaped portions of the first load transfer portion and the second load transfer portion are joined to the intermediate longitudinal plate portion.

8. The battery box for a vehicle according to claim 7, Among them, Between the intermediate longitudinal plate portion and the vehicle outer side wall portion, a plurality of vehicle outer side cross plate portions are provided. The outer ends in the vehicle width direction of the plurality of vehicle outer side cross plate portions are joined to the vehicle outer side wall portion, and the inner ends in the vehicle width direction of the plurality of vehicle outer side cross plate portions are joined to the joint portion of the intermediate longitudinal plate portion and the first load transfer portion or the joint portion of the intermediate longitudinal plate portion and the second load transfer portion.

9. The vehicle battery box according to claim 8, wherein, The plurality of vehicle outer side cross plate portions are configured as plate-like members that extend in the vehicle front-rear direction and in a direction inclined with respect to the vertical direction and the vehicle width direction.

10. The vehicle battery box according to claim 1, wherein, The pair of lower side beam structural members are joined to the vehicle body front portion structure constituting the front portion of the vehicle body at the front end portions, and are joined to the vehicle body rear portion structure constituting the rear portion of the vehicle body at the rear end portions.

11. The vehicle battery box according to claim 10, wherein, The front end portions of the pair of lower side beam structural members are respectively joined to the strength members in the vehicle body front portion structure that receive impact loads acting from the front, The rear end portions of the pair of lower side beam structural members are respectively joined to the strength members in the vehicle body rear portion structure that receive impact loads acting from the rear.

12. The vehicle battery box according to claim 10 or 11, wherein, The vehicle body front portion structure and the vehicle body rear portion structure are connected by a lower side beam skin member, The lower side beam skin member is configured to be able to cover the pair of lower side beam structural members from above respectively.

13. A vehicle battery box that houses a driving battery for supplying power to a driving source of a vehicle, wherein, It includes: A plate-like lower panel that is disposed substantially horizontally below the floor panel of the vehicle body, and the driving battery is placed on the upper surface of the lower panel; and A pair of lower side beam structural members that are respectively disposed at both side ends in the vehicle width direction of the lower panel, and an energy absorption portion configured to be able to absorb the load acting in the vehicle width direction is provided on the pair of lower side beam structural members, The energy absorption portion includes: an in-vehicle energy absorption portion; and an out-of-vehicle energy absorption portion, and the out-of-vehicle energy absorption portion is joined to the in-vehicle energy absorption portion and is formed on the outer side in the vehicle width direction compared to the in-vehicle energy absorption portion, The out-of-vehicle energy absorption portion is configured to be more difficult to deform than the in-vehicle energy absorption portion.

14. The vehicle battery box according to claim 13, wherein, The pair of lower side beam structural members include: An outer frame portion that extends in a cylindrical shape in the vehicle front-rear direction; and A plate-like intermediate longitudinal plate portion that is formed inside the outer frame portion and extends in the vehicle front-rear direction and the vertical direction, The outer frame portion includes: an inner vehicle side wall portion located on the inner side in the vehicle width direction; an outer vehicle side wall portion located on the outer side in the vehicle width direction with respect to the inner vehicle side wall portion; an upper wall portion that joins the upper ends of the inner vehicle side wall portion and the outer vehicle side wall portion; and a lower wall portion that joins the lower ends of the inner vehicle side wall portion and the outer vehicle side wall portion. The upper end of the intermediate longitudinal plate portion is joined to the upper wall portion, and the lower end of the intermediate longitudinal plate portion is joined to the lower wall portion. The space within the outer frame portion is divided by the intermediate longitudinal plate portion into an inner vehicle space on the inner side in the vehicle width direction compared to the intermediate longitudinal plate portion and an outer vehicle space on the outer side in the vehicle width direction compared to the intermediate longitudinal plate portion.

15. The vehicle battery box according to claim 14, wherein, The upper wall portion includes: an inner vehicle upper wall portion that constitutes a portion on the inner side in the vehicle width direction compared to the joining position of the upper wall portion and the intermediate longitudinal plate portion; and an outer vehicle upper wall portion that constitutes a portion on the outer side in the vehicle width direction compared to the joining position. The lower wall portion includes: an inner vehicle lower wall portion that constitutes a portion on the inner side in the vehicle width direction compared to the joining position of the lower wall portion and the intermediate longitudinal plate portion; and an outer vehicle lower wall portion that constitutes a portion on the outer side in the vehicle width direction compared to the joining position. A plurality of inner vehicle transverse plate portions that join the intermediate longitudinal plate portion and the inner vehicle side wall portion are formed within the inner vehicle space. A plurality of outer vehicle transverse plate portions that join the intermediate longitudinal plate portion and the outer vehicle side wall portion are formed within the outer vehicle space.

16. The vehicle battery box according to claim 15, wherein, The inner ends in the vehicle width direction of the plurality of outer vehicle transverse plate portions are joined to any one of the outer ends in the vehicle width direction of the plurality of inner vehicle transverse plate portions.

17. The vehicle battery box according to claim 15, wherein, The inner vehicle energy absorption portion is constituted by the inner vehicle upper wall portion, the inner vehicle lower wall portion, and the plurality of inner vehicle transverse plate portions. The outer vehicle energy absorption portion is constituted by the outer vehicle upper wall portion, the outer vehicle lower wall portion, and the plurality of outer vehicle transverse plate portions.

18. The vehicle battery box according to claim 17, wherein, The vehicle width direction dimension of the inner vehicle energy absorption portion is larger than the vehicle width direction dimension of the outer vehicle energy absorption portion.

19. The vehicle battery box according to any one of claims 15 to 18, wherein, The number of the plurality of outer vehicle transverse plate portions is larger than the number of the plurality of inner vehicle transverse plate portions.

20. The vehicle battery box according to any one of claims 15 to 18, wherein, A battery cross member is provided on the upper surface of the lower panel, extends in the vehicle width direction, and both ends in the vehicle width direction of the battery cross member are respectively joined to a pair of the lower side beam structural members. At least a part of the plurality of inner vehicle transverse plate portions is provided at a position overlapping with the battery cross member when viewed in the vehicle width direction.

21. The vehicle battery box according to claim 13, wherein, A pair of the lower side beam structural components are joined to a front body structure forming the front portion of the vehicle body at the front end, and the pair of the lower side beam structural components are joined to a rear body structure forming the rear portion of the vehicle body at the rear end.

22. A vehicle battery box that houses a driving battery for supplying power to a driving source of a vehicle, wherein, it includes: a plate-shaped lower panel that is disposed substantially horizontally below a floor panel of the vehicle body, and on which the driving battery is placed on an upper surface thereof; a pair of lower side beam structural components that are configured to be joined to both side ends in the vehicle width direction of the lower panel and extend along the vehicle longitudinal direction, and are formed in a cylindrical shape. The pair of lower side beam structural components are joined to a front body structure forming the front portion of the vehicle body at a front end portion on the front side, and are joined to a rear body structure forming the rear portion of the vehicle body at a rear end on the rear side. An energy absorption portion configured to be able to absorb energy of a load acting in the vehicle width direction is provided inside the pair of lower side beam structural components; and a battery cross member that is disposed on the upper surface of the lower panel, extends in the vehicle width direction, and both ends in the vehicle width direction of the battery cross member are joined to inner surfaces in the vehicle width direction of the pair of lower side beam structural components, respectively.

23. The vehicle battery box according to claim 22, wherein, it includes: a front frame that is provided along a front end of the lower panel and erected from the front end; and a rear frame that is provided along a rear end of the lower panel and erected from the rear end, the pair of the lower side beam structural components have: a front protruding end portion that protrudes forward with respect to the front frame; and a rear protruding end portion that protrudes rearward with respect to the rear frame, the front protruding end portion is joined to the front body structure, and the rear protruding end portion is joined to the rear body structure.

24. The vehicle battery box according to claim 23, wherein, the front protruding end portion and the rear protruding end portion each have an outer vehicle side surface facing the outside in the vehicle width direction and an inner vehicle side surface facing the inside in the vehicle width direction that are separately provided in the vehicle width direction, the front body structure is joined to the outer vehicle side surface and the inner vehicle side surface of the front protruding end portion of the pair of the lower side beam structural components, respectively, the rear body structure is joined to the outer vehicle side surface and the inner vehicle side surface of the rear protruding end portion of the pair of the lower side beam structural components, respectively.

25. The vehicle battery box according to claim 24, wherein, the front protruding end portion of the pair of the lower side beam structural components is detachably joined to the rear body structure, the rear protruding end portion of the pair of the lower side beam structural components is detachably joined to the rear body structure.

26. The vehicle battery box according to claim 25, wherein, the front body structure includes a vehicle inner mounting wall portion located inside the vehicle width direction of the front protruding end portion and a vehicle outer mounting wall portion located outside the vehicle width direction of the front protruding end portion, The front protruding end portion is detachably joined to the front body structure by a threaded member that penetrates the vehicle inner mounting wall portion from the vehicle width direction inner side of the vehicle inner mounting wall portion and engages with the vehicle inner side surface, and a threaded member that penetrates the vehicle outer mounting wall portion from the vehicle width direction outer side of the vehicle outer mounting wall portion and engages with the vehicle outer side surface. The rear body structure includes a vehicle inner mounting wall portion located on the vehicle width direction inner side of the rear protruding end portion and a vehicle outer mounting wall portion located on the vehicle width direction outer side of the rear protruding end portion. The rear protruding end portion is detachably joined to the rear body structure by a threaded member that penetrates the vehicle inner mounting wall portion from the vehicle width direction inner side of the vehicle inner mounting wall portion and engages with the vehicle inner side surface, and a threaded member that penetrates the vehicle outer mounting wall portion from the vehicle width direction outer side of the vehicle outer mounting wall portion and engages with the vehicle outer side surface.

27. The vehicle battery box according to claim 22, wherein the front body structure and the rear body structure are connected by a side sill skin member, the side sill skin member is configured to be able to cover a pair of the side sill structure members from above, respectively.

28. The vehicle battery box according to claim 22, wherein the front body structure includes a pair of left and right torque boxes as strength members for receiving loads applied from the front of the vehicle, the rear body structure includes a pair of left and right rear side members as strength members for receiving loads applied from the rear of the vehicle, a pair of the side sill structure members are respectively joined to the pair of left and right torque boxes at the front side ends and to the pair of left and right rear side members at the rear side ends.

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