Shock Test

The shock test is to represent the sudden decceleration of an object such as when it is dropped and hits the floor or it is involved in a crash. It can also be invoked in normal transport such as when a plan experiences turbulence or a vehicle is driven over a speed bump.

table for UN38.3 T4 shock test

In the process of updating UN38.3 transport testing requirements the sub-committee of experts [1] explain the physics behind the equations used in UN38.3 T4

COHSTA presentation showing deformation of larger battery packs on impact

COSHTA [2] explain this in their presentation:

  • So we have established two things:
    • Larger battery assemblies experience lower accelerations than smaller batteries during shock events in transportation due to the deformations in the system under load.
      • Therefore the constant acceleration test exposes larger batteries to disproportionally larger forces than they would experience in reality.
    • Battery Assemblies of higher mass experience forces in transportation that are not proportionally higher than batteries of smaller mass.
      • Therefore reduction in force from the constant acceleration line of T4 is warranted.
  • And the corollary of this is that the surface that an item is attached to for transport can only impart a maximum force on that item before it deforms under load.
    • An airplane floor, for instance, will deform significantly under the force that is necessary to accelerate a large battery assembly, thereby reducing the acceleration and the magnitude of the force.


  1. Report on the third meeting of the informal working group on testing large lithium batteries, Sub-Committee of Experts on the Transport of Dangerous Goods, UN/SCETDG/46/INF.11, October 2014
  2. Considerations About UN38.3 T4 Test, and its Applicability to Large Lithium Batteries, COSHTA