Vehicle body side section structure

1. A vehicle body side section structure comprising:

a rocker that is installed at a vehicle width direction outer side of a floor panel of a vehicle and that extends along a vehicle front-rear direction, the rocker includes an outer section positioned at the vehicle width direction outer side and an inner section positioned at a vehicle width direction inner side of the outer section and that forms a closed cross-section together with the outer section;

a floor cross member that is installed along a vehicle width direction above the floor panel so as so to form a gap between the floor cross member and the rocker, and that has a length direction along the vehicle width direction;

a battery pack that is installed at a vehicle lower side of the floor panel so as to be further toward an inner side than two length direction ends of the floor cross member in plan view; and

a floor cross extension that connects the rocker and the floor cross member together in the vehicle width direction, and that is set so as to undergo plastic deformation prior to the floor cross member in a side collision of the vehicle,

wherein an upper energy absorbing section is provided inside a rocker upper section configuring an upper section of the rocker so as to span in the vehicle width direction between the outer section and the inner section at a position overlapping with the floor cross member in the vehicle side view, and

wherein a yielding portion that is bent toward a vehicle vertical direction is formed at the floor cross extension at a rocker side within the gap.

2. The vehicle body side section structure of claim 1 , wherein a reinforcement that reinforces the battery pack is provided at the vehicle width direction outer side of the battery pack at a position overlapping with the rocker in a vehicle side view.

3. The vehicle body side section structure of claim 1 , wherein:

the floor cross member includes an upper face portion that configures an upper portion of the floor cross member and that is formed with a planar shape along a horizontal direction; and

the floor cross extension includes a join portion that configures one vehicle width direction end portion of the floor cross extension, that is formed with a planar shape along the horizontal direction, and that is joined to the upper face portion of the floor cross member.

4. The vehicle body side section structure of claim 1 , wherein the rocker includes:

a lower energy absorbing section that spans in the vehicle width direction between the outer section and the inner section inside the closed cross-section,

wherein a reinforcing portion that configures part of a reinforcement to reinforce the battery pack is provided between the battery pack and the rocker at a position overlapping with the lower energy absorbing section in a vehicle side view.

5. The vehicle body side section structure of claim 1 , wherein a rocker lower section configuring a lower section of the rocker is set so as to have a greater width dimension along the vehicle width direction than the rocker upper section configuring the upper section of the rocker.

6. The vehicle body side section structure of claim 1 , wherein the rocker includes:

a lower energy absorbing section that spans in the vehicle width direction between the outer section and the inner section inside the closed cross-section, wherein:

a reinforcing portion that configures part of a reinforcement to reinforce the battery pack is provided between the battery pack and the rocker at a position overlapping with the lower energy absorbing section in a vehicle side view, and

the lower energy absorbing section includes a first upper wall portion that extends substantially along a horizontal direction, a first lower wall portion that faces the first upper wall portion and that extends substantially along the horizontal direction, and a plurality of first coupling walls that span in a vehicle vertical direction between the first upper wall portion and the first lower wall portion and that are arranged along the vehicle width direction.

7. The vehicle body side section structure of claim 6 , wherein:

the upper energy absorbing section includes a second upper wall portion that extends substantially along the horizontal direction, a second lower wall portion that faces the second upper wall portion and that extends substantially along the horizontal direction, and a plurality of second coupling walls that span in the vehicle vertical direction between the second upper wall portion and the second lower wall portion and that are arranged along the vehicle width direction.

8. The vehicle body side section structure of claim 7 , wherein a plate thickness of each of the plurality of second coupling walls of the upper energy absorbing section is thicker than a plate thickness of each of the plurality of first coupling walls of the lower energy absorbing section.

9. The vehicle body side section structure of claim 1 , wherein:

the battery pack includes a battery case formed in a box shape having a length direction along the vehicle front-rear direction and being flattened in a vehicle vertical direction, a plurality of battery modules housed in an inner section of the battery case, and a tray that supports the battery case from the vehicle lower side; and

the tray includes a linking flange that juts out toward the rocker and that is linked to the rocker.

10. The vehicle body side section structure of claim 9 , wherein:

a reinforcement that reinforces the battery pack is provided at the vehicle width direction outer side of the battery pack at a position overlapping with the rocker in a vehicle side view; and

the reinforcement includes a joining tab that extends from a lower end of the reinforcement toward a lower side and that is joined to the tray.

11. A vehicle body side section structure comprising:

a rocker that is installed at a vehicle width direction outer side of a floor panel of a vehicle and that extends along a vehicle front-rear direction, wherein the rocker includes:

an outer section that is positioned at the vehicle width direction outer side;

an inner section that is positioned at a vehicle width direction inner side of the outer section and that forms a closed cross-section together with the outer section; and

a first energy absorbing section that spans in the vehicle width direction between the outer section and the inner section inside the closed cross-section, the first energy absorbing section includes a first upper wall portion that extends substantially along a horizontal direction, a first lower wall portion that faces the first upper wall portion and that extends substantially along the horizontal direction, and a plurality of first coupling walls that span in a vehicle vertical direction between the first upper wall portion and the first lower wall portion and that are arranged along the vehicle width direction,

a floor cross member that is installed along a vehicle width direction above the floor panel so as so to form a gap between the floor cross member and the rocker, and that has a length direction along the vehicle width direction;

a battery pack that is installed at a vehicle lower side of the floor panel so as to be further toward an inner side than two length direction ends of the floor cross member in plan view;

a floor cross extension that connects the rocker and the floor cross member together in the vehicle width direction, and that is set so as to undergo plastic deformation prior to the floor cross member in a side collision of the vehicle;

a reinforcing portion that configures part of a reinforcement to reinforce the battery pack provided between the battery pack and the rocker at a position overlapping with the first energy absorbing section in a vehicle side view,

wherein a second energy absorbing section is disposed inside a rocker upper section configuring an upper section of the rocker so as to span in the vehicle width direction between the outer section and the inner section at a position overlapping with the floor cross member in the vehicle side view, the second energy absorbing section includes a second upper wall portion that extends substantially along the horizontal direction, a second lower wall portion that faces the second upper wall portion and that extends substantially along the horizontal direction, and a plurality of second coupling walls that span in the vehicle vertical direction between the second upper wall portion and the second lower wall portion and that are arranged along the vehicle width direction,

wherein a plate thickness of each of the plurality of second coupling walls of the second energy absorbing section is thicker than a plate thickness of each of the plurality of first coupling walls of the first energy absorbing section.

12. The vehicle body side section structure of claim 11 , wherein a yielding portion that is bent toward a vehicle vertical direction is formed at the floor cross extension at a rocker side within the gap.

13. The vehicle body side section structure of claim 11 , wherein:

the floor cross member includes an upper face portion that configures an upper portion of the floor cross member and that is formed with a planar shape along a horizontal direction; and

the floor cross extension includes a join portion that configures one vehicle width direction end portion of the floor cross extension, that is formed with a planar shape along the horizontal direction, and that is joined to the upper face portion of the floor cross member.

14. The vehicle body side section structure of claim 11 , wherein a rocker lower section configuring a lower section of the rocker is set so as to have a greater width dimension along the vehicle width direction than the rocker upper section configuring the upper section of the rocker.