PACK-level explosion-proof valve (the one installed on the battery pack housing)

Where is the explosion-proof valve of new energy vehicles usually installed in the battery pack?
The mainstream arrangement is to open on the side of the box cover/side wall of the box, with the valve body in a vertical or inclined position. A vehicle is usually equipped with 6 to 12 such valves, distributed along the module, and it is required that the orientation of each cell explosion-proof valve aligns with the module pressure relief channel to ensure a smooth emission path.
Why the side, rather than the top cover or bottom plate:
location
Question
Upward (top cover)
Water accumulation, dust accumulation, and debris blocking the breathable membrane; more importantly, the heat-induced uncontrolled airflow erupts upward, directly towards the passenger cabin
Downward (base plate)
During pressure relief, high-temperature airflow directly hits the chassis, bounces off the ground, and impacts the valve body directly due to ground support, wading, and road salt spray
Side view
Facilitate directional emission – direct high-temperature exhaust gas to the side/bottom of the vehicle, avoiding the passenger compartment and high-pressure components; meanwhile, it is less prone to water and dust accumulation
In addition to this major principle, there are two positional constraints: it should be installed on the leeward side of the driving direction (to avoid long-term impact of high-speed airflow entraining dust on the breathable membrane), and a vent space of no less than 10 mm should be reserved on the outside of the valve body. There should be no wire harness pressing on the top, otherwise the valve core cannot be opened during bursting.
Battery cell-level explosion-proof valve (the one integrated into the individual battery cell)
This is another layer, and its position is determined by the shape of the battery cell:
Cylinder (18650/2170): on the positive side
Square (pole at the same end): At the output pole end, vertically upwards
Square shape (with poles distributed at both ends, like blades): arranged horizontally at one end
Soft pack: There is no clear explosion venting direction, which is the main reason why thermal runaway of soft pack is difficult to achieve