Particle size distribution in Li battery single particle model

Hello, I want to add a particle size distribution to a negative electrode in Li battery single particle model. In fact, the goal is to define a multi particle model instead of a single particle model. For that, a Weibull distribution should be defined within a PSD range. How could I do that? The Weibull distribution is defined by: number fraction density=(k/λ)(R/λ)^(k-1)exp(-(R/λ)^k) Thanks for your help in advance.