In general, a side impact is a very bad scenario for the party being hit. There's not much room for crumple zones at all, and cars are often not rigid enough,

In general, a side impact is a very bad scenario for the party being hit. There's not much room for crumple zones at all, and cars are often not rigid enough, leading to an intrusion by the other vehicle. But this is true for larger vehicles as well, e.g. older Ford F150s were famous for basically folding in half from the slightest side hit (say, a telephone pole at low speeds after losing control). In this situation, a rigid battery pack might actually make the car a lot safer. But yes, I wouldn't want to be in a tiny car getting hit from the side by a larger one.