(JP9231950-A)      The battery comprises a prismatic battery case with an opening and an electrode and electrolyte contained in the battery case. A cover closes the battery case opening by sealing. The case has several flat plane sections, a corner section situated between each flat plane section, and a junction section situated between the corner section and each flat plane section. The corner section has a curvature at least on the inner surface and the junction section has a thickness that is smaller than that of the flat plane section and also that of the corner section.    A position of the thinnest section of the junction section coincides with a position where a radius of a circular arc forming an inner surface of the corner section crosses perpendicularly an inner surface of the flat plane section.    ADVANTAGE -   Increased volume for accommodating electrode group thereby allowing higher volumetric density. Improved heat dissipation efficiency. Enhanced charge and discharge efficiency. Longer life.    (US5827621-A)      The battery comprises a prismatic battery case with an opening and an electrode and electrolyte contained in the battery case. A cover closes the battery case opening by sealing. The case has several flat plane sections, a corner section situated between each flat plane section, and a junction section situated between the corner section and each flat plane section. The corner section has a curvature at least on the inner surface and the junction section has a thickness that is smaller than that of the flat plane section and also that of the corner section.    A position of the thinnest section of the junction section coincides with a position where a radius of a circular arc forming an inner surface of the corner section crosses perpendicularly an inner surface of the flat plane section.    ADVANTAGE -   Increased volume for accommodating electrode group thereby allowing higher volumetric density. Improved heat dissipation efficiency. Enhanced charge and discharge efficiency. Longer life.    (EP791970-B1)      The battery comprises a prismatic battery case with an opening and an electrode and electrolyte contained in the battery case. A cover closes the battery case opening by sealing. The case has several flat plane sections, a corner section situated between each flat plane section, and a junction section situated between the corner section and each flat plane section. The corner section has a curvature at least on the inner surface and the junction section has a thickness that is smaller than that of the flat plane section and also that of the corner section.    A position of the thinnest section of the junction section coincides with a position where a radius of a circular arc forming an inner surface of the corner section crosses perpendicularly an inner surface of the flat plane section.    ADVANTAGE -   Increased volume for accommodating electrode group thereby allowing higher volumetric density. Improved heat dissipation efficiency. Enhanced charge and discharge efficiency. Longer life.