I always thought it was too dangerous for him to use it.
At the start of TPM Obi-Wan and Qui-Gon use it to escape. They are running away from danger. But if Obi-Wan had used it in the battle then he would have been heading straight into danger i.e Maul, at an incredible speed. It wouldn't have been hard for Maul to kill him.
Plus there was that great pit which he could have easily gone over. Then there was the energy gates which could have killed him if they shut at the wrong time.
And Jedi are only supposed to use the force for defence, not attack.
I think it's just a case of knowing when it's safe to use it. Neither Qui-Gon or Obi-Wan used it in the swamps when they were trying to escape the battle droids, probably because they didn't know where they were going.