As we can see below, to implement s_corrected and v_corrected, we need to use t (function argument). But i believe we need to use for loop variable l. Can someone help me differentiate l and t in this context and also in exponentially weighted average context? Any help appreciated.

t is the iteration number on the overall loop, whereas l is (as you say) the layer number of the network. It requires that you understand the meaning of the math formula there. Notice that t is used as the exponent for \beta_1 and \beta_2. The point is that the EWA is happening individually at each layer w.r.t. the “timestep” or iteration count t.

So it is because we use EWA for mini-batches and we need to count mini-batches to calculate v_corrected and s_corrected. If we use batch gradient descent then it is ok to use just l. Right?
Thank you for the previous answer.

No, the l and the t are completely different quantities. The t value changes every "step"or “iteration”, right? This function is being called multiple times for multiple steps one for each iteration. For each step, you process all the layers.