Presented are anti-buckling cables for battery assembly shear plates, methods for making/using such anti-buckling cables, and electric-drive vehicles equipped with traction battery packs having impact-attenuating shear plates joined by anti-buckling cables. A battery assembly includes multiple battery cells, such as lithium-class prismatic, pouch, or can-type cells arranged in rows and columns, that are housed inside a protective battery container, such as an electrically insulated battery pack housing. A pair of rigid, impact-attenuating (top and bottom) shear plates is attached to opposing (top and bottom) sides of the battery container, sandwiching therebetween the battery cells. An engineered pattern of tether cables extends through the battery container with cable each rigidly secured at opposing ends thereof to the two shear plates. The tether cables are electrically non-conductive and structurally join together the vertically spaced, mutually parallel shear plates. Each of the tether cables may be continuously tensioned between the shear plates.