Abstract: A battery case is made by cutting from a blank case of a bottomed cylindrical battery case having an unwanted portion at an opening portion the unwanted portion from the case wall in the circumferential direction by a blade. The cutting of the case wall is performed so as to render a cutting-end portion higher than a cutting-start portion. Thus, re-cutting of the cutting-start portion by the blade after it has already completed one rotation can be avoided. As a result, the generation of thread-like chips from re-cutting of the cut surface can be avoided.

Abstract: A battery case is made by cutting from a blank case of a bottomed cylindrical battery case having an unwanted portion at an opening portion the unwanted portion from the case wall in the circumferential direction by a blade. The cutting of the case wall is performed so as to render a cutting-end portion higher than a cutting-start portion. Thus, re-cutting of the cutting-start portion by the blade after it has already completed one rotation can be avoided. As a result, the generation of thread-like chips from re-cutting of the cut surface can be avoided.

Abstract: To provide a battery can into which an electrode assembly can be housed smoothly without causing damage to the electrode assembly while ensuring the strength of the opening portion. In the battery can including a cylindrical side portion, a bottom, and an opening portion, the cylindrical side portion includes a first side portion formed at the bottom side, and a second side portion formed at the opening portion side. The thickness T1 of the first side portion and the thickness T2 of the second side portion are adjusted to satisfy a relational expression: T1<T2, and the inner diameter of the cylindrical side portion is constant from the opening portion side to the bottom side.

Abstract: A battery case (1) has a cutting groove (10) formed on its elongated side surface (1a). Between a groove bottom surface of the cutting groove (10) and an inner surface of the battery case (1) is provided a thin-walled easily-rupturable portion (12) designed to rupture at an instant when an internal pressure of the battery case (1) reaches a predetermined value. Thereby, a safety mechanism for use with a prismatic battery is realized. The manufacture of the safety mechanism is as follows. A cutting blade (37) rotated at a high speed by a high-speed rotary body (30) is brought into cutting engagement with the elongated side surface (1a) of the battery case (1) of the prismatic battery in finished form until it reaches a predetermined depth and is fixed, and subsequently the high-speed rotary body (30) or the prismatic battery is brought into rectilinear relative movement.

Abstract: A prismatic battery case with high dimensional precision is manufactured, while pursuing an improvement in productivity, with a manufacturing method of a prismatic battery case that includes a first step for molding an intermediate cup body (8) by impact molding a pellet (7) of prescribed shape, and a second step for molding a prismatic battery case (9) with a cross section of substantially rectangular shape by DI processing the intermediate cup body (8). The DI processing conducts drawing and ironing continuously, in one action.

Abstract: Battery case for containing electrode assembly and electrolyte of electroltic battery has a grid on at least a portion of an inner surface of the case, formed by intersecting pluralities of first and second ridges. The grid enables construction of a battery case of minimal thickness while having high strength and rigidity, and resistance to deformation caused by generation of higher internal battery pressure during use.

Abstract: A battery case (1) has a cutting groove (10) formed on its elongated side surface (1a). Between a groove bottom surface of the cutting groove (10) and an inner surface of the battery case (1) is provided a thin-walled easily-rupturable portion (12) designed to rupture at an instant when an internal pressure of the battery case (1) reaches a predetermined value. Thereby, a safety mechanism for use with a prismatic battery is realized. The manufacture of the safety mechanism is as follows. A cutting blade (37) rotated at a high speed by a high-speed rotary body (30) is brought into cutting engagement with the elongated side surface (1a) of the battery case (1) of the prismatic battery in finished form until it reaches a predetermined depth and is fixed, and subsequently the high-speed rotary body (30) or the prismatic battery is brought into rectilinear relative movement.

Abstract: A prismatic battery case with high dimensional precision is manufactured, while pursuing an improvement in productivity, with a manufacturing method of a prismatic battery case that includes a first step for molding an intermediate cup body (8) by impact molding a pellet (7) of prescribed shape, and a second step for molding a prismatic battery case (9) with a cross section of substantially rectangular shape by DI processing the intermediate cup body (8). The DI processing conducts drawing and ironing continuously, in one action.

Abstract: A battery having a stable internal resistance with a small deviation of internal resistance, and capable of suppressing a change or elevation of internal resistance due to external impact is provided. The battery comprises a battery can having a conductivity, serving also as a negative terminal, and including an opening, a spiral electrode group disposed in the battery can, a positive plate and a negative plate wound around a separator, an electrolyte member disposed in the battery can, and a sealing member serving also as a positive terminal, disposed in the opening of the battery can through an electric insulating member. In the inner wall of the battery can, contacting with the negative electrode positioned on the outermost circumference of the plate group, plural linear bumps vertical to the bottom of the battery can are formed. The height of each linear bump of the plural linear bumps ranges from 0.05 mm to 0.25 mm, and the pitch of the linear bumps ranges from 0.5 mm to 10 mm.

Abstract: This invention relates to a method to manufacture cell-cans by DI can method, by manufacturing a bottomed cylindrical cup-shaped intermediate product from a sheet material of which both surfaces are nickel plated and annealed in an atmosphere of inert gas making the metal nickel layer thickness and the hardness at predetermined values, then ironing the intermediate product at a predetermined ironing rate, securing a thickness of the metal nickel layer of more than 1.0 .mu.m and a Vickers hardness of more than HV 200 on the side wall of finished cell-cans. By this, conventional defect problems due to the cracks generated on the intermediate product can be solved completely and the problem of hair-lines formed on the surface of finished cell-can can be eliminated.