Abstract: In a stack type battery containing a stacked electrode assembly in which a positive electrode plate having a positive electrode current collector tab extending therefrom and a negative electrode plate having a negative electrode current collector tab extending therefrom are alternately stacked interposing a separator therebetween, a through portion for positioning that passes through in the thickness direction is formed in at least one of the positive and negative electrode current collector tab, and the width at the through portion-unformed position of the positive or negative electrode collector tab is 50 mm or more, and the width of the through portion for positioning is 10% or less of the width at the through portion-unformed position of the positive or negative electrode current collector tab.

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 tensile stress is applied to solidified resin. The tensile stress is so small that the solidified resin formed in the sprue by solidification of molding material does not break and is so large that the solidified resin formed in the sprue is separated from the inner surface of the sprue due to a reduction in the diameter of the cross sectional area thereof. For the application of such a tensile stress, the runner stripper plate holding the solidified resin is moved away from the nozzle and sprue bushing. This state is maintained for a predetermined time to separate the solidified resin from the inner surface of the sprue.

Abstract: A top sealing plate used for a battery includes a filter, a cap, and a valve body. The filter has a valve hole and upper opening; the cap has a convex portion and a flange portion disposed around the convex portion; the opening end of the upper opening of the filter has a bend portion; and the outer periphery end of the flange portion of the cap and the bend portion are caulked and joined to each other. The caulked portion includes both states of contact, that is, a strong contact portion and a weak contact portion, between the surface of the outer periphery end of the flange portion and the bend portion. By this configuration, the electric contact resistance between the cap and the filter will be greatly reduced. In addition, the contact resistance is stabilized at a low level. Further, the internal resistance of the battery is lowered, thereby improving the battery performance.

Abstract: A tensile stress is applied to solidified resin. The tensile stress is so small that the solidified resin formed in the sprue by solidification of molding material does not break and is so large that the solidified resin formed in the sprue is separated from the inner surface of the sprue due to a reduction in the diameter of the cross sectional area thereof. For the application of such a tensile stress, the runner stripper plate holding the solidified resin is moved away from the nozzle and sprue bushing. This state is maintained for a predetermined time to separate the solidified resin from the inner surface of the sprue.

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 metal can blank having a shape surrounded by n external tangents, n partial arcs or partial lines, and 2n linear or arc-shaped connect lines is used to produce a metal can. Each external tangent is a line shorter than one side of a regular n-gon circumscribed about a circle, with the midpoint being a point of contact between each of the n sides of the regular n-gon and the circle. Each partial arc is a part of the circle positioned between the adjacent external tangents in the circumferential direction of the circle. Each partial line is a line connecting both ends of the partial arc. Each connect line is a line connecting one end of the external tangent with the most adjacent end of the partial arc or partial line. The material yields, productivity, etc. of such metal cans are significantly improved, and high quality metal cans can be obtained.

Abstract: A bottomed cylindrical battery can of the present invention includes a bottom wall and a side wall each having a predetermined thickness and being uniform in thickness. Alternatively, the bottomed cylindrical battery can of the present invention includes a side wall having a predetermined thickness and being uniform in thickness therethroughout and a bottom wall having a bottom wall thickness increasing from the periphery to the center thereof. By thus configuring, it is possible to reduce the weight of the battery can without sacrificing the rigidity of the battery can, while achieving a reduction in the amount of material used.

Abstract: The battery electrode plate includes a core member (1) which is densely coated with a mixture paste chiefly including an active material (2). The core member (1) is made of a metal sheet (3), which is formed with rows (8) of first and second bowed portions (4, 7) arranged along one direction (X) of the metal sheet so as to protrude alternately on the front and back sides of the metal sheet, the rows (8) of bowed portions arranged along the direction (Y) orthogonal to the direction (X) with flat parts (9) of a predetermined width interposed between each two rows. The battery electrode plate is produced by any of a reciprocating type continuous press method, a rotary type molding method, and an electrolytic deposition method.

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: In a first process, an electrically conductive thin metal plate 7 is subjected to a press molding process employing a plurality of punches 3 in a primary molding block 1 and a plurality of dies 4 in a secondary molding block 2, so as to form therein a plurality of hollow projections 9 that project from one side of the metal plate 7, and bulges 14 that bulge out in a direction opposite to that of the projections 9, positioned between the projections 9. In a second process, the metal plate 7 on which have been formed the plurality of projections 9 and bulges 14 is subjected to either chemical etching or electrolytic etching, so as to form through holes 17 by corrosively removing thin-walled portions 11 from the tips of the projections 9, and, at the same time, to corrosively form innumerable fine irregularities 18 over the entire surface of the metal plate 7.

Abstract: The battery electrode plate includes a core member (1) which is densely coated with a mixture paste chiefly including an active material (2). The core member (1) is made of a metal sheet (3), which is formed with rows (8) of first and second bowed portions (4, 7) arranged along one direction (X) of the metal sheet so as to protrude alternately on the front and back sides of the metal sheet, the rows (8) of bowed portions arranged along the direction (Y) orthogonal to the direction (X) with flat parts (9) of a predetermined width interposed between each two rows. The battery electrode plate is produced by any of a reciprocating type continuous press method, a rotary type molding method, and an electrolytic deposition method.

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: An apparatus and method for producing expanded mesh sheets provides for forming fine slits in a metal sheet at a slit section by plate cutters, but excluding portions in a center and both sides in a widthwise direction of the metal sheet. The areas where the slits have been formed are drawn out at an expanding section thereby opening the slits and obtaining a mesh sheet which has solid portions in the central portion and on both sides. The mesh sheet is flattened at a rolling device to obtain the expanded mesh sheet. An electrode sheet is prepared by applying an active material onto mesh portions of the expanded mesh sheet, and collectors for a battery are cut out from the electrode sheet such that lead connecting portions thereof are located at the solid portion of the mesh sheet where there are no openings.

Abstract: A method for manufacturing an expanded mesh sheet, includes the steps of: forming a plurality of slits on a strip at predetermined pitches to simultaneously form a plurality of strip-shaped lift portions and connecting portions for connecting the strip-shaped lift portions to each other in a lattice pattern, the slits each being intermittently formed in a longitudinal direction of the strip and the adjacent slits in a widthwise direction of the strip being shifted to each other in the longitudinal direction of the strip; and expanding the strip in the widthwise direction thereof. An apparatus for manufacturing the sheet, includes: a pair of rolls engaged to each other, each roll having a plurality of disk-shaped cutters; and a driving device for driving the rolls for rotation.

Abstract: A method for manufacturing an expanded mesh sheet, includes the steps of: forming a plurality of slits on a strip at predetermined pitches to simultaneously form a plurality of strip-shaped lift portions and connecting portions connecting the strip-shaped lift portions to each other in a lattice pattern, the slits each being intermittently formed in a longitudinal direction of the strip and the intermittent pattern of adjacent slits in a widthwise direction of the strip being offset from each other in the longitudinal direction of the strip; and expanding the strip in the widthwise direction thereof. An apparatus for manufacturing the sheet, includes: a pair of rolls in coacting meshing engagement with each other, each roll having a plurality of disk-shaped cutters; and a driving device for rotating the rolls. Each cutter has cutting edge portions and reliefs on a periphery thereof at predetermined pitches.