Vehicle substructure

1. A vehicle substructure, comprising:

a pair of side members arranged apart in a vehicle width direction, and extending in a vehicle longitudinal direction;

a battery arranged between the pair of side members; and

a cross member that extends in the vehicle width direction and connects the pair of side members,

wherein the cross member includes a pair of cross member low-strength sections that are of weaker strength than a center portion, on both sides in the vehicle width direction,

wherein the pair of cross member low-strength sections are formed of low-strength members that are separate from the center portion of the cross member,

wherein each of the pair of cross member low-strength sections has a low-strength outer portion and a low-strength inner portion, the low-strength outer portion is fixed to a respective side member of the pair of side members,

wherein the low-strength inner portion is located between the low-strength outer portion and the center portion, and an inner end of the low-strength inner portion is fixed to the center portion of the cross member, and

wherein the pair of cross member low-strength sections as a whole, have a lower strength than the central portion.

2. The vehicle substructure of claim 1 , wherein:

the pair of cross member low-strength sections are positioned outside of the battery in the vehicle width direction.

3. The vehicle substructure of claim 1 , wherein:

the pair of cross member low-strength sections include outer sections connected to the pair of side members by bolts.

4. The vehicle substructure of claim 2 , wherein:

the pair of cross member low-strength sections include outer sections connected to the pair of side members by bolts.

5. The vehicle substructure of claim 1 , wherein:

the pair of cross member low-strength sections are constructed as separate members to the center portion of the cross member, and include inner sections fixed to both ends of the center section of the cross member.

6. The vehicle substructure of claim 5 , wherein:

the inner sections of the pair of cross member low-strength sections are fixed to the center portion of the cross member by welding.

7. The vehicle substructure of claim 1 , wherein:

the cross member is positioned below the battery, and both ends of the cross member are fixed to the pair of side members at positions outside of the battery in the vehicle width direction.

8. The vehicle structure of claim 1 , wherein the cross member includes a plurality of cross members each extending in the vehicle width direction, and

wherein the pair of cross member low-strength sections are formed at both ends of each cross member.