Non-aqueous electrolyte secondary battery and battery module

A battery module comprising:

• (a) a stack in which at least two non-aqueous electrolyte secondary batteries are stacked in at least a thickness direction thereof;
• (b) end plates placed at both ends of said stack, said both ends being the ends in the thickness direction of each of said batteries;
• and
• (c) at least two bridges for connecting one of said end plates with the other of said end plates to bind said batteries, wherein
• each of said batteries comprises an electrode assembly, a non-aqueous electrolyte, and a substantially rectangular battery case for housing said electrode assembly and said non-aqueous electrolyte,
• said battery case having a thickness α, a width β, and a height γ satisfying a relation α<β≦γ:
• wherein said electrode assembly includes a positive electrode, a negative electrode, and a porous heat-resistant layer disposed between said positive electrode and said negative electrode;
• said positive electrode includes a positive electrode active material layer and said negative electrode includes a negative electrode active material layer;
• a ratio of a pore volume in a predetermined area of said porous heat-resistant layer to a theoretical capacity of each of said batteries is 0.18 to 1.117 ml/Ah, said predetermined area having a same area as said positive electrode active material layer;
• a porosity of said porous heat-resistant layer is 35 to 85%,
• said porous heat-resistant layer includes a porous sheet comprising a heat-resistant resin;
• a thickness of said porous heat-resistant layer is 2 to 20 μm;
• and
• a ratio of a thickness Y of said end plate to a thickness α of the battery case, Y/α, is 0.4 to 2.