The　shape　of　cathode　electrode　affects　severely　the　potential　curves　of　charge/discharge　process　of　lithium　ion　cells.　In　this　paper,　we　take　LiFePO(4)　for　an　example.　The　square　model　is　presented　to　predict　the　concentration　of　lithium　on　the　cathode　electrode　under　some　simplified　conditions.　With　the　square　model　as　a　tool,　effects　of　shape　and　position　are　determined　and　analyzed.　Meanwhile,　the　lithium　transportation,　Gibbs　free　energy,　and　battery　potential　are　proved　to　be　different　from　that　of　sphere　models.　It　shows　that　asymmetry　of　electrode　materials　makes　a　great　impact　on　the　performance　of　charge　or　discharge　process.