Battery module

A battery module comprising:

• a plurality of cylindrical batteries each comprising:
• a shaft core;
• a set of wound electrodes comprising an electrode stack wound around the shaft core and comprising a positive electrode, a negative electrode, and an electrolyte provided between the positive and negative electrodes stacked;
• a first fastener provided at a first axial end of the shaft core;
• a second fastener provided at a second axial end of the shaft core;
• and an exterior member surrounding the set of wound electrodes,
• adjacent ones of the cylindrical batteries being fastened together with the first and second fasteners,
• wherein the cylindrical batteries each further comprise:
• a first cap disposed at the first axial end and electrically connected to one of the positive and negative electrodes;
• and a second cap disposed at the second axial end and electrically connected to another of the positive and negative electrodes,
• wherein the first and second caps each have a slope region that is substantially symmetrically inclined with respect to the shaft core,
• wherein the positive electrode includes a positive electrode current collector, and the negative electrode includes a negative electrode current collector,
• wherein the positive electrode current collector has an extension portion extending from a first axial end of the set of wound electrodes,
• wherein the negative electrode current collector has an extension portion extending from a second axial end of the set of wound electrodes,
• wherein the extension portion of one of the positive and negative electrode current collectors has parts gathered and electrically connected to the shaft core, and
• wherein the extension portion of another of the positive and negative electrode current collectors has parts gathered and electrically connected to the exterior member.