Heat transfer experiments and correlations for vent gases emerging from a Li-ion battery and impinging on a flat surface

•Impingement heat transfer for venting of Li-ion cells was considered.•Infrared thermography provides spatially resolved heat transfer distribution.•Peak heat transfer occurs near stagnation point for each jet emerging from the vent.•Asymmetric heat transfer distribution was caused by complex safety vent geometry.•Local and area-averaged heat transfer correlations were developed.