Prismatic battery having electrolyte injection-hole capable of excellent sealing-disposition

A method for forming a prismatic battery, the method comprising:

• mounting an electrode assembly in a prismatic battery case having a base plate;
• forming an electrolyte injection hole having an inside upper end configured to have a downwardly tapering incline structure in the base plate;
• providing a metal sphere having an initial radius in contact with the inside upper end of the electrolyte injection hole;
• sealing the electrolyte injection hole by plastically deforming the metal sphere therewithin;
• and
• covering the forcibly inserted metal ball and electrolyte periphery with epoxy resin,
• wherein the downward taper incline structure has a width corresponding to 5% to 30% of the initial radius of the metal sphere and a depth corresponding to 10% to 25% of the initial radius of the metal sphere, and the downward taper structure is inclined downward at an angle of 20 to 70 degrees from a surface defining the upper end of the base plate.

A system for sealing a prismatic battery comprising:

• a prismatic battery case;
• an electrode assembly disposed within the prismatic battery case;
• a base plate disposed on the prismatic battery case;
• an electrolyte injection hole disposed in the base plate, the electrolyte injection hole having an inside upper end with a downwardly tapering incline structure;
• and
• a metal sphere having an initial radius disposed on the inside upper end of the electrolyte injection hole;
• and
• an epoxy resin is disposed on the plastically deformed metal ball and the forcibly inserted region,
• wherein the metal sphere is configured to be plastically deformed within the electrolyte injection hole and the downward taper incline structure has a width corresponding to 5% to 30% of the initial radius of the metal sphere and a depth corresponding to 10% to 25% of the initial radius of the metal sphere, and the downward taper incline structure is inclined downward at an angle of 20 to 70 degrees from a surface defining the upper end of the base plate.