Square battery

Abstract

A battery case (1, 8), substantially square in cross section, has four lateral walls (5, 6) each of which is gradually arc-shaped to expand outwardly with a radius of curvature R1. The cross section is adapted to satisfy equation R1 / r=4 to 20, where r is the distance between a midpoint (C2) of each lateral wall (5, 6) and the center point (C1) in the cross section of the battery case (1, 8) and R1 is the radius of curvature. In addition, the battery case (8) is rounded at each corner with a radius of curvature of R2, and has a cross section that satisfies equation R2 / r=0.3 to 0.8, where r is the distance between the midpoint (C2) of each lateral wall (6) and the center point (C1) in the cross section of the battery case (8) and R2 is the radius of curvature of each corner.

Description

technical field [0001] The present invention relates to a closed rectangular battery formed by enclosing an electric energy generating element in a battery case with a substantially rectangular cross section. technical background [0002] In recent years, with the development of various portable electric appliances, the development of batteries, which serve as their driving power sources, has also received attention as an important key device. In particular, small secondary batteries such as rechargeable nickel-metal hydride batteries and lithium secondary batteries are used in mobile phones, notebook computers, and video cameras, and in recent years as driving power sources for hybrid electric vehicles. development, and its demand is expanding. [0003] In recent years, there has been a strong demand for miniaturization and thinning of electrical equipment such as mobile phones, and there has also been an increasing demand for miniaturization and thinning of batteries, whi...

AI Technical Summary

Problems solved by technology

[0006] However, although the method of providing a thick wall part in a part of the battery case can prevent the deformation of the battery case against the increase in the internal pressure of the battery, it has the disadvantage that the outer shape of the battery case becomes larger and it cannot be miniaturized.

On the other hand, the method of increasing the wall thickness of the corner of the rectangular battery case can prevent the deformation of the battery case from the increase of the internal pressure of the battery while preventing the external shape of the battery case from becoming larger, but the disadvantages are: The volume of the battery case decreases, the filling amount of each active material of the positive electrode and the negative electrode in the electrode group decreases, and the energy density per unit volume decreases

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