JP5470922B2 - Lead-acid battery and method for manufacturing the same - Google Patents

Description

  The present invention relates to a lead storage battery in which the respective ears of a positive electrode plate and a negative electrode plate constituting an electrode plate group are connected by a strap cast by a cast-on method, and a method for manufacturing the same.

  When manufacturing a lead-acid battery, as shown in Patent Document 1, a positive electrode plate and a negative electrode plate are alternately stacked via a separator to form an electrode plate group. A process of casting a strap for connecting the ears by a cast-on method is performed.

  FIG. 9 shows an electrode plate group used in a conventional lead-acid battery. In the conventional lead-acid battery, the positive electrode plate 1 and the negative electrode plate 2 are respectively formed by filling the positive electrode grid body and the negative electrode grid body with the positive electrode active material and the negative electrode active material, respectively, and then the ear portions 1a of the positive electrode plate 1 and the negative electrode plate 2. , 2a are cut in the width direction so that the height dimension of the ear parts 1a, 2a is a predetermined dimension, and the shape of the tip part of the ear parts 1a, 2a is perpendicular to both end corners in the width direction. The electrode plate group 4 was configured by alternately laminating the positive electrode plates 1 and the negative electrode plates 2 with the separators 3 interposed therebetween. When casting a strap that connects the ear portions 1a of the positive electrode plates and the ear portions 2a of the negative electrode plate constituting the electrode plate group 4, as shown in FIG. 10, a mold hole 5A of the strap casting mold 5 is used. And 5B, after injecting a molten lead or lead alloy, the ear plate 1a of the series of negative electrode plates 1 and the ear portion 2a of the positive electrode plate 2 are connected to the strap casting mold 5 with the electrode plate group 4 turned upside down. The anode strap 6 and the cathode strap 7 are cast by inserting into the molten metal in the mold cavities 5A and 5B and waiting for the molten metal in the mold cavity to cool and solidify in this state.

  Further, in the lead storage battery disclosed in Patent Document 2, as shown in FIG. 12, the ear portion 1a 'of the electrode plate is cut obliquely from the tip end to the base end portion side of the ear portion 1a'. The strap 6 is cast by inserting the ear 1a 'into the molten metal in the mold hole until the tip 1a1' contacts the bottom surface of the mold hole 5A of the strap casting mold 5.

JP-A-6-196146 JP-A-5-109398

  When the strap is cast by the conventional method shown in FIGS. 9 and 10, the tips of the ear portions 1a and 2a of the positive electrode plate 1 and the negative electrode plate 2 are cut in the width direction before the electrode plate group is formed. Therefore, the portions other than the front end surfaces of the ear portions 1a and 2a were still in the state covered with the oxide film. Since the portion covered with the oxide film of the ear portion is difficult to melt when immersed in the molten metal in the mold, it can be reliably melted when the straps 6 and 7 are cast on the ear portions 1a and 2a by the conventional method. As shown by a thick line in FIG. 11A, only the tip surfaces of the ear portions 1a and 2a (parts where the oxide film was removed by cutting) could be made. Therefore, there is a problem that in the welded portion between the ear portions 1a and 2a and the straps 6 and 7, it is not possible to increase the number of portions that are reliably welded with sufficient penetration. The ratio of the amount of power that can be taken out from the outside to the amount of power generated by the electrode plate group) has been a bottleneck.

  When the electrode plate group 4 is turned upside down and the ears 1a of the negative electrode plate 1 and the ears 2a of the positive electrode plate 2 are inserted into the molten metal in the mold holes 5A and 5B of the strap casting mold 5, The ears 1a and 2a are preferably inserted in the center in the width direction of the mold cavities 5A and 5B. Actually, however, the insertion positions of the ears 1a and 2a are the end sides in the width direction of the mold cavities 5A and 5B. As shown in FIG. 11 (B), the strap may be cast in a state of being close to one side in the width direction of the strap of the ear portions 1a and 2a. When the straps 6 and 7 are cast in such a state, portions 6p and 7p having a small cross-sectional area and a large electric resistance are formed on one side in the width direction of the straps 6 and 7, and the portion 6p having a large electric resistance is formed. 7p is in contact with the entire height of the ears embedded in the strap, so that the current flow from the side surface of each ear to the strap is suppressed, and the current collection efficiency from the electrode plate group There was a problem that decreased.

  As shown in FIG. 12, if the ear portion 1a is cut obliquely from the distal end to the proximal end portion to form an inclined surface at the distal end of the ear portion, the surface from which the oxide film of the ear portion 1a is removed 11 can be an inclined surface that is inclined with respect to the width direction of the ear portion, as shown in FIG. 11, the ear portion is melted as compared with the case where the tip of the ear portion is cut only in the width direction. It is expected that the area of the area to be expanded can be expanded.

  However, in the vicinity of the bottom of the mold hole of the strap casting mold, the heat of the molten metal is deprived due to heat conduction from the molten metal to the mold, and the temperature rapidly decreases, so the tip of the ear contacts the bottom of the mold hole. If the ear part and the strap are welded in such a state, the ear part is insufficiently melted near the tip of the ear part, and there is a possibility that the welding between the ear part and the strap becomes incomplete.

  Also, in the mold cavity, the temperature of the molten metal decreases from the opening side toward the bottom side, so if the tip of the ear is cut diagonally over the whole, the tip of the ear will be Even when the bottom surface is not contacted, the temperature distribution of the inclined surface of the ear portion becomes uneven, and the entire inclined surface of the ear portion may not be uniformly welded to the strap. Therefore, it is necessary to avoid making the entire front end surface of the ear part an inclined surface.

  Furthermore, in the conventional lead-acid battery, the cross-sectional shape of the strap is rectangular, but when the cross-sectional shape of the strap is rectangular, the corners at both ends in the width direction of the strap and the corners at both ends in the width direction of the ear portion The distance between the lead and the lead alloy becomes longer than necessary, and the amount of lead or lead alloy is excessive in this portion, which is not preferable for saving the amount of lead or lead alloy used for forming the strap. In particular, when an inclined surface is formed at the tip of the ear as shown in FIG. 12, if the cross section of the strap is rectangular, the cross-sectional area of the portion adjacent to the inclined surface of the strap becomes excessive, and lead forming the strap Or the amount of lead alloy is inevitable.

  In addition, in order to weld the strap to the ear part well, it is necessary to immerse the ear part in the molten metal in the mold hole before the molten metal injected into the mold hole begins to solidify. If it is larger, the mold hole for casting the strap becomes larger and the time required to fill the mold hole with the molten metal becomes longer.So, the molten metal solidifies near the bottom of the mold hole before inserting the ear part into the molten metal. May start, which is not preferable. In order to achieve good welding between the ear and the strap, it is preferable to make the cross-sectional area of the strap as small as possible.

  An object of the present invention is to provide a lead-acid battery that improves the current collection efficiency by increasing the number of portions where the ear and the strap are welded with sufficient penetration at the connection between the ear and the strap of the electrode plate, and It is providing the method of manufacturing this lead acid battery.

  Another object of the present invention is to increase the current collecting efficiency by increasing the number of portions where the ear and the strap are welded with sufficient penetration at the connection between the ear and the strap of the electrode plate. It is an object of the present invention to provide a lead-acid battery and a method for manufacturing the lead-acid battery, in which the temperature distribution at the tip part of the ear part is sometimes brought close to a uniform state so that the ear part and the strap can be favorably welded.

  Another object of the present invention is to increase the number of portions where the ear portion and the strap are securely welded with sufficient penetration at the connection portion between the ear portion of the electrode plate and the strap, and the ear portion of the negative electrode plate and the positive electrode plate. When the strap is cast in a state where the ear is shifted to one side in the width direction of the strap, the electrical resistance between the ear and the strap is suppressed from increasing at both ends in the width direction of the ear, An object of the present invention is to provide a lead-acid battery and a method for manufacturing the lead-acid battery that can prevent the current collection efficiency from decreasing.

  Still another object of the present invention is to increase the current welding efficiency by increasing the number of parts where the ear and the strap are sufficiently welded with sufficient penetration, and to reduce the cross-sectional area of the strap to form the strap. It is an object of the present invention to provide a lead-acid battery and a method for manufacturing the lead-acid battery that can save the amount of lead or lead alloy required.

  In the present invention, a positive electrode plate and a negative electrode plate are alternately laminated via a separator to form an electrode plate group, and then the electrode plate group is contained in a molten lead or lead alloy poured into a mold cavity of a strap casting mold. The lead-acid battery manufacturing method of inserting the ear | edge part of the same polarity electrode plate and casting the strap which connects the ear | edge parts of the same polarity electrode plate is made into object.

In the present invention, before forming the electrode plate group, the step of cutting the tip of the ear portion of each electrode plate in the width direction and the step of chamfering the corners in the width direction of the tip of the ear portion of each electrode plate. And forming a tip surface extending linearly along the width direction of each electrode plate at the center in the width direction of the tip end of each electrode plate, and both ends in the width direction of the tip of each electrode plate ear. An inclined surface that is inclined at an angle θ set with respect to the tip end surface is formed at the corner. Further, a flat surface is formed in the center of the bottom surface of the mold hole of the strap casting mold in the width direction so as to face the tip surface of the ear portion, and both ends of the flat surface in the width direction are formed at both ends of the bottom surface of the mold hole. Is formed when the strap is cast by inserting the ear part of each electrode plate into the molten metal poured into the mold hole. The height h1 from the surface facing the electrode plate group side of the strap to the end of the inclined surface of the ear portion on the electrode plate group side, and the pole of the inclined surface of the strap from the surface facing the electrode plate group side of the strap The relationship of h2> h1 is established between the height h2 up to the end on the plate group side. Then, the tip end surface of each electrode plate and the entire chamfered portion are inserted into the molten metal in the rear mold hole constituting the electrode plate group, and the tip surface and the inclined surface of each electrode plate ear in the molten metal. A strap that satisfies the relationship of h2> h1 is cast in a state where the surface is floated from the bottom surface of the mold cavity.

  In the present specification, the width direction of the electrode plate means a direction perpendicular to both the thickness direction and the height direction of the electrode plate, and the width direction of the ear portion of the electrode plate is along the width direction of the electrode plate. Direction (direction perpendicular to both the thickness direction and the height direction of the ear). Furthermore, the tip of the ear portion refers to the outermost end portion (the end portion on the opposite side of the lattice body) in the protruding direction from the lattice body of the ear portion.

  The width direction of the strap refers to the direction along the width direction of the electrode plate (the width direction of the ear portion) in a state where the strap is welded to the ear portion of the electrode plate, and is the direction of the bottom of the mold hole of the strap casting mold. The width direction means a direction along the width direction of the strap to be cast.

  As described above, before forming the electrode plate group, the step of cutting the tips of the ears of each electrode plate in the width direction and the step of chamfering both end corners in the width direction of the tips of the ears of each electrode plate And forming a tip surface extending linearly along the width direction of each electrode plate at the center in the width direction of the tip end of each electrode plate, and both ends in the width direction of the tip of each electrode plate ear. If the corners are chamfered, the chamfered portions at both ends in the width direction can be used as the new surface from which the oxide film has been removed, as well as the tip surfaces of the ears of each electrode plate. Not only the surface but also the obliquely chamfered portions at both ends in the width direction of the front end portion of the ear portion can be sufficiently melted so that the strap and the ear portion can be well welded.

  In addition, as described above, when the strap is cast in the molten metal with the tip and inclined surfaces of the ears of each electrode plate floating from the bottom of the mold cavity, heat escapes from the ears through the bottom of the mold cavity. Since it can prevent, heat can be sufficiently supplied to the ear | edge part and the cut | disconnected part of the front-end | tip of an ear | edge part can fully be fuse | melted.

Further, as described above, when the both end corners in the width direction of the tip portion of the ear portion are chamfered, as shown in FIG. 12, the tip of the ear portion is cut as the entire tip portion of the ear portion is cut obliquely. for the temperature distribution does not become non-uniform, substantially uniformly melt the entire tip portion of the ear portion including a chamfered portion, it is possible to satisfactorily perform the welding of the ears and the strap collector Electric efficiency can be improved.

  In addition, as described above, if the corners at both ends in the width direction of the ear portion are chamfered, the strap is cast in a state where the ear portion of the negative electrode plate and the ear portion of the positive electrode plate are shifted to one side in the width direction of the strap. In this case, since the portion having a large electrical resistance formed on one side in the width direction of the strap can be reduced, it is possible to prevent the current collection efficiency from being lowered.

  In addition, as described above, if the inclined surfaces inclined toward the opening side of the mold hole are formed at both ends in the width direction of the bottom surface of the mold hole of the strap casting mold, the side opposite to the electrode plate group of the cast strap Since the corners at both ends in the width direction of the end portion facing the chamfer are chamfered, the corners at both ends (inclined surfaces) in the width direction of the strap and the corners at both ends (inclined surfaces) in the width direction of the ears By reducing the distance between them, the cross-sectional area of the strap can be reduced, and the amount of lead or lead alloy forming the strap can be saved.

  In addition, as described above, when the inclined surfaces inclined to the opening side of the mold hole are formed at both ends in the width direction of the bottom surface of the mold hole of the strap casting mold, the mold hole of the mold hole is compared with the case where the inclined surface is not formed. Since the volume can be reduced, it is possible to reduce the time required to fill the mold cavity with molten lead or lead alloy prior to inserting the ear into the mold cavity. Therefore, it is possible to prevent the molten metal from solidifying in the vicinity of the bottom of the mold cavity before inserting the ear portion into the molten metal, and to favorably weld the ear portion and the strap.

  The present invention is also configured such that, among the electrode plates constituting the electrode plate group, the ears protruding from the upper part of the series of electrode plates of the same polarity are integrated with the ears of the series of electrode plates. Intended for lead-acid batteries connected by cast straps.

In the present invention, the tips of the ears of each electrode plate constituting the electrode plate group are cut in the width direction, and both end corners in the width direction of the tip of each electrode plate are chamfered, and each electrode plate A flat tip surface is formed at the center in the width direction of the tip of each ear portion, and inclined surfaces that are inclined with respect to the tip surface are formed at both ends in the width direction of the tip of each electrode plate. The strap is cast with the tip and slopes of the ears of a series of electrode plates embedded inside, and the center in the width direction of the end of the strap facing away from the electrode plate group is flat. A tip end surface of an ear portion formed such that corners at both ends in the width direction of the end portion are chamfered, and a flat portion of the strap and a portion of the chamfered shape are embedded therein, and It is made to oppose an inclined surface. In the present invention, the height h1 from the surface of the strap facing the electrode plate group side to the end of the sloping surface of the ear portion on the electrode plate group side, and the surface of the strap facing the electrode plate group side of the strap The strap is cast so that a relationship of h2> h1 is established between the inclined surface and the height h2 to the end on the electrode plate group side.

  As described above, the tips of the ears of each electrode plate constituting the electrode plate group are cut in the width direction, and the corners in the width direction of the tips of the ears of each electrode plate are chamfered, and each electrode plate A flat tip surface is formed at the center in the width direction of the tip of each ear portion, and inclined surfaces inclined with respect to the tip surface are formed at both ends in the width direction of the tip portion of each electrode plate, When each strap is cast so that the tip end surface and the inclined surface of the ear portion of the electrode plate are embedded in the strap, not only the tip end surface of the ear portion but also the chamfered portion is sufficiently melted and the strap is melted. Therefore, in the welded part between the ear part and the strap, it is possible to increase the number of parts that are securely welded with sufficient penetration, and to reduce the electrical resistance of the connection part between the ear part and the strap. The current collection efficiency from the plate group can be improved.

  In addition, as described above, if the corners at both ends in the width direction of the ear portion are chamfered, the strap is cast in a state where the ear portion of the negative electrode plate and the ear portion of the positive electrode plate are shifted to one side in the width direction of the strap. In this case, a portion having a large electrical resistance formed on one side in the width direction of the strap can be reduced, so that it is possible to prevent the current collection efficiency from the electrode plate group from being lowered.

  Further, as described above, if the corners at both ends in the width direction of the strap are chamfered, both end corners (inclined surfaces) in the width direction of the straps and both end corners in the width direction of the ears (inclined surfaces) ) To reduce the amount of lead or lead alloy that forms the strap, and each ear of the electrode plate is chamfered This saves the amount of lead or lead alloy constituting the electrode plate, thereby reducing the cost of the battery.

  The chamfering of the corners at both ends in the width direction and the chamfering at both ends in the width direction of the strap are preferably C chamfering.

  If the chamfering at both ends in the width direction of the tip of each electrode plate is a C chamfer (chamfering along a direction inclined 45 degrees with respect to the width direction of the ear), the effect of reducing the amount of lead in each electrode plate Can be increased.

  According to the method for manufacturing a lead-acid battery according to the present invention, the step of cutting the tips of the ears of each electrode plate in the width direction before constituting the electrode plate group, and both ends in the width direction of the tips of the ears of each electrode plate And chamfering the corners to form a flat tip surface at the center in the width direction of the tips of the ears of each electrode plate, and to form inclined surfaces at the corners in the width direction of the tip of each electrode plate. Since it is formed, not only the front end surface of the ear portion of each electrode plate but also the inclined surfaces at both ends in the width direction can be formed as new surfaces from which the oxide film has been removed. Therefore, not only the front end surface of the ear portion but also the inclined surfaces at both ends in the width direction of the front end portion of the ear portion can be sufficiently melted so that the strap and the ear portion can be well welded.

In the present invention, the strap is cast in the molten metal in a state where the tip end surface and the inclined surface of the ear portion of each electrode plate are floated from the bottom surface of the mold cavity, so that heat escapes from the ear portion through the bottom of the mold cavity. It is possible to prevent this, and sufficient heat can be supplied to the ear portion to sufficiently melt the cut portion of the tip of the ear portion. Also, if the corners in the width direction of the tip part of the ear part are chamfered, the temperature distribution at the tip of the ear part will not be uneven as if the entire tip part of the ear part is cut obliquely, The entire tip of the ear portion including the chamfered portion is melted almost uniformly, so that the ear portion and the strap can be favorably welded, and the current collection efficiency can be improved.

  Further, according to the present invention, since the corners at both ends in the width direction of the ear portion are chamfered, the strap is cast in a state where the ear portion of the negative electrode plate and the ear portion of the positive electrode plate are shifted to one side in the width direction of the strap. In this case, it is possible to reduce the portion of the strap that has a large electrical resistance formed on one side in the width direction and prevent the current collection efficiency from decreasing.

  Further, according to the present invention, the inclined surfaces inclined toward the opening side of the mold hole are formed at both ends in the width direction of the bottom surface of the mold hole of the casting mold for strap casting. As the shape of the corner is chamfered, it is possible to reduce the distance between both end corners (inclined surfaces) in the width direction of the strap and both end corners (inclined surfaces) in the width direction of the ears, The strap cross-sectional area can be reduced to save the amount of lead or lead alloy forming the strap.

  Further, according to the present invention, the volume of the mold cavity can be reduced by forming the inclined surfaces inclined toward the opening side of the mold cavity at both ends in the width direction of the bottom surface of the mold cavity of the strap casting mold. Prior to inserting the ear portion into the mold cavity, the time required to fill the mold cavity with molten lead or lead alloy can be shortened. Therefore, it is possible to prevent the molten metal from solidifying in the vicinity of the bottom of the mold cavity before inserting the ear portion into the molten metal, and to favorably weld the ear portion and the strap.

  In the lead-acid battery according to the present invention, the corners at both ends in the width direction of the tips of the ears are chamfered so that the tip surfaces and the chamfered portions of the ears of each electrode plate are completely embedded in the strap. Since each strap is cast, not only the front end surface cut linearly in the width direction of the front end of the ear, but also the diagonally chamfered portion must be melted sufficiently and securely welded to the strap Can do. Therefore, in the welded portion between the ear portion and the strap, the portion that is securely welded with sufficient penetration can be increased, and the electrical resistance of the connection portion between the ear portion and the strap can be reduced. The current collection efficiency can be improved.

  In the present invention, since the corners at both ends in the width direction of the ear portion are chamfered, the strap is cast in a state where the ear portion of the negative electrode plate and the ear portion of the positive electrode plate are shifted to one side in the width direction of the strap. In this case, it is possible to prevent the current collection efficiency from the electrode plate group from being reduced by reducing the portion of the strap that has a large electrical resistance formed on one side in the width direction.

  Furthermore, according to the present invention, the corners at both ends in the width direction of the strap are chamfered so that the distance between the corners at both ends in the width direction of the strap and the corners at both ends in the width direction of the ears is increased. The cross-sectional area of the strap can be reduced to reduce the amount of lead or lead alloy that forms the strap, and the lead that comprises the electrode plate by chamfering each ear of the electrode plate Alternatively, coupled with the ability to save the amount of lead alloy, the cost of the battery can be reduced.

It is the front view which showed the electrode group used with the lead acid battery concerning one Embodiment of this invention, and the strap cast by the ear | edge part of this electrode group. It is a right view of FIG. It is the front view which expanded and showed the ear | edge part of the electrode plate used with the lead acid battery concerning one Embodiment of this invention, and the strap cast by this ear | edge part. (A) and (B) are enlarged views of the ears of the electrode plate used in the lead-acid battery according to the present embodiment and the straps cast on the ears. (A) is the IVA of (B). -IVA A cross-sectional view, (B) is a side view. In this embodiment, it is sectional drawing which showed the state cast in the state which the strap biased to the one side of the width direction of an ear | edge part. FIG. 4 is a cross-sectional view showing an example in which a strap having a rectangular cross section is cast on an ear portion whose both ends in the width direction are chamfered. It is the perspective view which showed the electrode group which comprises the lead acid battery of this embodiment. (A) is a cross-sectional view showing a state in which the ear portion of the electrode plate is inserted in the mold hole of the strap casting mold in this embodiment, (B) is a mold hole of the strap casting mold, It is an expanded sectional view of the principal part which showed the ear | edge part inserted in the mold cavity. It is the perspective view which showed the electrode group used by the conventional lead acid battery. FIG. 6 is a cross-sectional view showing a state in which an ear portion of an electrode plate is inserted while obtaining molten metal in a mold hole of a strap casting mold in the process of manufacturing a conventional lead-acid battery. (A) is sectional drawing which showed the state in which the strap was correctly cast by the ear | edge part of the electrode plate in the conventional lead acid battery. (B) is sectional drawing which showed the state cast in the state in which the strap was biased to the one side of the width direction of the ear | edge part of an electrode plate in the conventional lead acid battery. FIG. 10 is a cross-sectional view showing a state in which an ear portion of an electrode plate is inserted into a mold hole of a strap casting mold in the process of manufacturing another conventional lead-acid battery.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 7 schematically shows the structure of the electrode plate group used in this embodiment. In FIG. 7, 11 is a negative electrode plate, 12 is a positive electrode plate, and 13 is between the negative electrode plate 11 and the positive electrode plate 12. It is an arranged separator. A predetermined number of the negative electrode plates 11 and the positive electrode plates 12 are provided, and the negative electrode plates 11 and the positive electrode plates 12 are alternately stacked via the separators 13 to constitute the electrode plate group 14.

  The negative electrode plate 11 is a lattice body made of a lead alloy and filled with a negative electrode active material, and an ear portion 11a projects from the upper portion of the lattice body. In the present invention, after the grid body is filled with the negative electrode active material and before the electrode plate group is formed, the tip of the rectangular ear portion 11a projecting from the upper end of the grid body of each negative electrode plate is arranged in the width direction. Perform a step of cutting linearly and a step of chamfering both end corners in the width direction of the tip of each ear, and in the width direction of each electrode plate in the center of the width direction of the tip of each ear. A flat front end surface 11a1 that extends linearly along the end is formed, and an angle θ set with respect to the front end surface 11a1 (relative to the width direction) at both end corners in the width direction of the front end of each electrode plate (see FIG. 3). Inclined surfaces 11a2 and 11a2 which are inclined only by reference) are formed. For this reason, the tip portion of each ear portion 11a has a tip surface 11a1 extending linearly along the width direction of the electrode plate at the center in the width direction of the tip, and inclined surfaces (chamfered portions) 11a2 and 11a2 at the tip. It exhibits a trapezoidal shape at both ends in the width direction. The front end surface 11a1 of the ear portion 11a and the inclined surfaces 11a2 and 11a2 at both ends in the width direction are formed by cutting the ear portions of the lattice body, and thus are new surfaces from which the oxide film has been removed. In the present embodiment, the chamfering at both ends in the width direction of the tip of the ear portion 11a is a C chamfering (chamfering with θ = 45 °).

  The step of cutting the tip of the ear portion 11a in the width direction can be performed using a rotary cutter or a shearing cutter. Usually, when shifting from the step of filling the electrode plate with the active material to the step of cutting the ears, a series of electrode plates are linearly conveyed along the respective width directions by the conveyor. In this case, if a rotary cutter is used as a cutter that cuts the tip of the ear portion 11a in the width direction, the step of cutting the tip of the ear portion of the electrode plate in the width direction can be performed without stopping the conveyance of the electrode plate, Mass productivity can be increased.

  The step of obliquely cutting and chamfering both end corners in the width direction at the tip of each ear 11a can also be performed using a rotary cutter or a shearing cutter. When performing the process of obliquely cutting and chamfering both end corners in the width direction at the tip of each ear portion 11a using a rotary cutter, the cutting of both end corners in the width direction of the ear portion is performed using the rotary cutter. It is possible to incline with respect to the width direction, and without inclining the rotary cutter, rotate the electrode plate side and incline it so that the width direction of the ear is inclined with respect to the rotary cutter. May be.

  The positive electrode plate 12 is a lattice body made of a lead alloy and filled with a positive electrode active material, and has an ear portion 12a protruding above the lattice body. Similarly to the ear portion 11a of the negative electrode plate shown in FIG. 2, the tip end of the positive electrode plate 12 is formed after the grid body is filled with the positive electrode active material and before the electrode plate group is formed. Perform a step of cutting in the width direction and a step of chamfering both end corners in the width direction of the tip, and straight line along the width direction of each plate at the center in the width direction of the tip of the ear portion of each plate And the inclined surfaces 12a2 and 12a2 which are inclined at an angle θ set (relative to the width direction) with respect to the front end surface 12a1 at both end corners in the width direction of the front end of each electrode plate. Is formed. Accordingly, the tip of the ear 12a of the positive electrode plate also has a tip 12a1 extending linearly along the width of the electrode at the center of the tip in the width direction, and inclined surfaces 12a2, 12a2 in the width of the tip. It exhibits a trapezoidal shape at both ends.

  The ears 11a, 11a, ... of the series of negative electrodes 11, 11, ... and the ears 12a, 12a, ... of the series of positive plates 12, 12, ... Are arranged so as to be aligned in a line in the laminating direction of the electrode plates at one end side and the other end side in the width direction.

  In the lead-acid battery manufacturing method according to the present invention, after the electrode plate group 14 is formed, the negative electrode strap 16 and the positive electrode strap 17 that connect the negative electrode tabs 11a and the positive electrode tabs 12a to each other are cast. I do. In the step of casting the negative strap and the positive strap, as shown in FIGS. 8A and 8B, a strap casting mold 5 having mold holes 5A and 5B for casting the negative strap 16 and the positive strap 17, respectively. Is used. In the strap casting mold 5 used in the manufacturing method of the present invention, a flat surface 5A1 facing the tip surface 11a1 of the ear 11 is formed at the center in the width direction of the bottom surface of the mold hole 5A for casting the negative strap 16. Slopes 5A2 and 5A2 extending at an angle θ from both ends of the flat surface 5A1 in the width direction to the opening side of the mold hole 5A are formed at both ends in the width direction of the bottom surface of the mold cavity. Further, a flat surface 5B1 opposite to the tip surface 12a1 of the ear portion 12 is formed at the center in the width direction of the bottom surface of the mold hole 5B for casting the positive strap 17, and the flat surfaces 5B1 are formed at both ends of the bottom surface of the mold hole in the width direction. Slopes 5B2 and 5B2 extending at an angle of θ from both ends in the width direction of the mold cavity 5B are formed in advance.

  When casting the straps 16 and 17, the mold holes 5A and 5B of the strap casting mold 5 are filled with molten lead or lead alloy, and then the electrode plate group 14 is pressed in the stacking direction with a predetermined pressure. In this state, the ears 11a and 12a are inserted downward into the molten metal in the mold cavities 5A and 5B. At this time, the tip surfaces 11a1, 12a1 and the inclined surfaces (chamfered portions) 11a2, 12a2 of the ear portions 11a, 12a of the electrode plates 11, 12 are completely buried in the molten metal, and the tip surfaces 11a1 of the ear portions 11a, 12a. , 12a1 are kept floating in the molten metal by a predetermined distance d from the bottom surfaces of the mold cavities 5A, 5B.

  In this state, waiting for the molten metal in the mold cavities 5A and 5B to be cooled and solidified, as shown in FIGS. 1 and 2, the negative straps 16 and the plurality of negative straps 16 that connect the ears 11a of the negative plates 11 are connected. The positive electrode strap 17 that connects the ears 12a of the positive electrode plate 12 is cast.

  In FIGS. 1 and 2, 16b and 17b are flag portions formed at the end portions of the negative strap 16 and the positive strap 17, respectively, and these flag portions accommodate the electrode plate group in the cell chamber of the battery case. Later, it is connected to a flag portion provided in a predetermined strap of an adjacent cell by an inter-cell connecting portion.

  As described above, the step of cutting the tips of the ear portions 11a, 12a of the electrode plates 11, 12 in the width direction before the electrode plate group 14 is configured, and the width of the tips of the ear portions 11a, 12a of the electrode plates 11, 12 When the both end corners of the direction are cut obliquely, not only the front end surfaces of the ear portions of the electrode plates 11 and 12 but also the chamfered inclined surfaces are surfaces from which the oxide film has been removed. When the ear portions 11a and 12a are inserted into the melt in the mold cavities 5A and 5B, not only the front end surfaces 11a1 and 12a1 of the ear portions 11a and 12a but also diagonally at both ends in the width direction of the front end portions of the ear portions. The chamfered portions 11a2 and 12a2 can be sufficiently melted and reliably welded to the strap.

  Further, as described above, when the strap 16 is cast in a state where the tip surfaces of the ear portion 11a of the negative electrode plate 11 and the ear portion 12a of the positive electrode plate 12 are floated from the bottom surfaces of the mold cavities 5A and 5B, respectively, the ear portion 11a And 12a do not contact the bottom of the mold cavities 5A and 5B, so that heat can be prevented from escaping from the ears 11a and 12a through the bottom of the mold cavities 5A and 5B, and sufficient heat is supplied to the ears. The tip surfaces and chamfered portions of the ear portions 11a and 12a can be sufficiently melted.

As described above, when the both end corners in the width direction of the tip of the ear portion 11a are chamfered and the shape of the tip portion of the ear portion is trapezoidal, the temperature of the tip of the ear portion increases as the entire ear portion is cut obliquely. Since the distribution does not become non-uniform, the entire end surfaces of the end portions of the ear portions 11a and 12a including the tip surface linearly cut in the width direction and the chamfered portion are melted almost uniformly, and It is possible to favorably weld the portion and the strap.

  Further, as described above, chamfering the corners in the width direction at the tips of the ears 11a and 12a can reduce the amount of lead or lead alloy constituting each electrode plate, so that lead used in lead-acid batteries is used. Alternatively, the cost can be reduced by reducing the amount of the lead alloy.

  Further, as described above, when the corners at both ends in the width direction of the ear portions 11a and 12a are chamfered, as shown in FIG. 5, the ear portion 11a of the negative electrode plate and the ear portion 12a of the positive electrode plate are connected to the strap 16 and When the strap is cast in a state shifted to one side in the width direction of 17, the portions 16 p and 17 p having high electrical resistance formed on one side in the width direction of the strap are reduced, and the current collection efficiency from the electrode plate group is reduced. It can be prevented from lowering.

  As described above, if the inclined surfaces 5A2 and 5B2 that are inclined toward the opening side of the mold hole are formed at both ends in the width direction of the bottom surfaces of the mold holes 5A and 5B of the strap casting mold 5, the cast straps are formed. The corners at both ends in the width direction 16 and 17 are chamfered. Accordingly, the straps 16 and 17 are formed in a shape having flat tip surfaces 16a1 and 17a1 at the center in the width direction of the tips and inclined surfaces 16a2 and 17a2 at both ends in the width direction of the tips. The front end surfaces 16a1 and 17a1 of the straps 16 and 17 are opposed to the front end surfaces 11a1 and 12a1 of the electrode plates 11 and 12, and the inclined surfaces (the chamfered portions) 16a2 and 17a2 of the straps 16 and 17 are electrode plates, respectively. The inclined surfaces 11 and 12 are chamfered 11a2 and 12a2.

  In the conventional lead-acid battery, as shown in FIG. 6, straps 16 'and 17' having a rectangular cross-sectional profile are used. When chamfering both ends in the width direction at the tips of the ears 11a and 11b, if the straps 16 'and 17' having a rectangular cross section are used, the corners and the ears in the width direction at the tips of the straps 16 'and 17' are used. Since the distance L ′ between the inclined surfaces 11a2 and 12a2 at both ends in the width direction of the portions 11a and 12a becomes longer, the cross-sectional area of the strap is larger than necessary compared to the size of the portion embedded in the strap of the ear portion. Become bigger. If the strap has a large cross-sectional area, the volume of the mold cavity of the mold for casting the strap increases, so it takes a long time to fill the mold cavity with the molten metal, and the ear of the electrode plate is placed in the molten metal in the mold cavity. There is a risk that the solidification of the molten metal starts near the bottom of the mold cavity until the insertion.

  On the other hand, if inclined surfaces 16a2 and 17a2 are formed at both ends in the width direction of the tips of the straps 16 and 17 as in the present invention, the width direction of the tips of the straps 16 and 17 is formed as shown in FIG. The distance L between the both end corners and the inclined surfaces 11a2 and 12a2 at both ends in the width direction of the ears 11a and 12a can be shortened to reduce the cross-sectional area of the strap. The ability to reduce the cross-sectional area of the strap not only saves the amount of lead or lead alloy that forms the strap, but also reduces the volume of the mold cavity casting the strap, so The time required to fill the mold with the molten metal can be shortened to eliminate the possibility of the solidification of the molten metal starting near the bottom of the mold cavity before inserting the ears of the electrode plate into the molten metal in the mold cavity. It is possible to improve the current collection efficiency from the electrode plate group by favorably performing casting of the strap and welding of the strap and the ear portion of the electrode plate.

  In the lead-acid battery according to the present invention, the strap has an inclination angle of the inclined surfaces at both ends in the width direction equal to an inclination angle of the inclined surfaces at both ends in the width direction of the ear portion embedded therein, and the flat surface of the strap is It is preferable that the thickness of the formed portion is not excessive. Therefore, for example, in the ear 12a and the strap 17 of the positive electrode plate, as shown in FIG. 4, when the width dimension of the flat surface 17a1 at the tip of the strap 17 is A and the width dimension of the tip face of the ear is B, It is preferable to cast the strap so that the relationship of A> B is established. The relationship between the width dimension A of the flat surface 17a1 at the tip of the strap 17 and the width dimension C (> B) of the ear portion 12a may be A ≧ C or A <C.

In addition, when the position of the ear part is shifted to one side in the width direction of the strap to the limit, if the inclined surface on one side in the width direction of the ear part is in contact with the inclined surface of the strap, This is not preferable because the area of is reduced. Therefore, it is preferable to prevent the inclined surface of the ear portion from coming into contact with the inclined surface of the strap even when the position of the ear portion is shifted to one side in the width direction of the strap. For this purpose, in FIG. 4, the height from the surface of the strap facing the electrode plate group side to the lower end of the inclined surface 12a2 of the ear 12a ( the end of the inclined surface 12a2 on the electrode plate group side) is h1, When the height from the surface facing the electrode plate group to the lower end of the inclined surface 17a2 of the strap ( the end of the inclined surface 17a2 on the electrode plate group side) is h2, the relationship of h2> h1 is established. The strap 17 is preferably cast. If the strap 17 is cast so that such a relationship is established, when the ear portion 12a is inserted into the mold cavity 5B, the insertion position of the ear section is extremely shifted in the width direction of the mold cavity. Even if the portion closer to the lower side (closer to the electrode plate) than the lower end of the inclined surface 12a2 of the ear portion 12a is in contact with the inner surface of the outermost end portion in the width direction of the mold cavity 5B, the inclined surface of the ear portion 12a. Since 12a2 does not contact the inclined surface 17a2 of the strap 17, the reduction amount of the portion welded to the strap of the ear portion 12a can be minimized.

  The relationship between the dimensions A, B, and C and the relationship between h1 and h2 are the same for the ear portion 11a of the negative electrode plate and the strap 16 when connected to the ear portion.

  When manufacturing a lead storage battery, after casting a strap to the electrode plate group as described above, the electrode plate group is inserted into each cell chamber in the battery case, and a predetermined plate group in the adjacent cell chamber is inserted. The inter-cell connecting portions are formed by welding the flag portions of the straps through through holes provided in advance in the partition walls between the cells. Thereafter, the battery case lid is attached and the upper end opening of each cell chamber is closed. Thereafter, an electrolytic solution is injected into each cell chamber from a liquid injection port provided on the lid of the battery case.

  In the present invention, both end corners in the width direction of the tips of the ears of each electrode plate are chamfered. However, if the chamfering amount of the ears is excessively increased, the temperature distribution becomes uneven on the inclined surface of the chamfered portion. In some cases, insufficient melting may occur and current collection efficiency may be reduced. Therefore, the amount of chamfering at both corners in the width direction of the tip of each electrode plate is set to a size within a range where the current collection efficiency can be improved as compared with the case where chamfering is not performed. The appropriate value of the chamfering amount at the corners in the width direction at the tip of each electrode plate can be easily obtained by performing an experiment for performing a high rate discharge test with various chamfering amounts.

  The amount of chamfering at the corners in the width direction at the tip of each electrode plate is as high as possible in reducing the amount of lead as long as the current collection efficiency can be improved compared to when chamfering is not performed. It is preferable to set as follows. In order to increase the effect of saving the amount of lead or lead alloy, each chamfer is preferably a C chamfer.

  In said embodiment, after performing the process of cutting the front-end | tip of the ear | edge part of an electrode plate in the width direction, and the process of cutting and chamfering the both-ends corner | angular part of the width direction of the front-end | tip of the electrode plate diagonally Although the electrode plate group is configured, a process of brushing the cut surface may be further performed before the electrode plate group is configured.

5 Cast Casting Mold 5A Mold Hole 5A1 Flat Surface 5A2 Slope 5B Mold Hole 5B1 Flat Surface 5B2 Slope 11 Negative Electrode 11a Negative Plate Ear 11a1 Ear Tip 11a2 Ear End Slope 12 Positive Plate 12a Ear portion 12a1 Ear portion 12a2 Inclined surface at both ends of ear portion 13 Separator 14 Electrode group 16 Negative strap 16a1 Flat surface 16a2 Inclined surface 17 Positive strap 17a1 Flat surface 17a2 Inclined surface

Claims (3)

After the positive electrode plate and the negative electrode plate are alternately laminated via the separator to form the electrode plate group, the same polarity of the electrode plate group is introduced into the molten lead or lead alloy injected into the mold hole of the strap casting mold. In the method of manufacturing a lead-acid battery, the step of casting the strap for connecting the ears of the electrode plates of the same polarity to each other is inserted,
Before constituting the electrode plate group, the step of cutting the tip of the ear portion of each electrode plate in the width direction and the step of chamfering both end corners in the width direction of the tip of the ear portion of each electrode plate, A tip end surface extending linearly along the width direction of each electrode plate is formed in the center in the width direction of the tip end of each electrode plate, and at the corners in the width direction of the tip end of each electrode plate An inclined surface that is inclined by an angle θ set with respect to the tip surface is formed,
A flat surface is formed at the center in the width direction of the bottom surface of the mold hole of the casting mold for strap casting so that the front end surface of the ear portion is opposed to the width direction of the bottom surface of the mold hole. When casting a strap by forming an inclined surface extending at an angle θ from both ends toward the opening of the mold cavity and inserting the ears of each electrode plate into the molten metal poured into the mold cavity The height h1 from the surface of the cast strap facing the electrode plate group side to the end of the inclined surface of the ear portion on the electrode plate group side, and the slope surface of the strap from the surface facing the electrode plate group side of the strap The relationship of h2> h1 is established with the height h2 to the end of the electrode plate group side of
After the electrode plate group is configured, the tip end surface of each electrode plate and the entire chamfered portion are inserted into the molten metal in the mold cavity, and the tip surface of each electrode plate ear is inserted in the melt. Casting a strap satisfying the relationship of h2> h1 with each inclined surface floating above the bottom surface of the mold cavity;
A method for producing a lead-acid battery. Among the electrode plates constituting the electrode plate group, straps cast so that the ears protruding from the top of a series of electrode plates of the same polarity are integrated with the ears of the series of electrode plates In connected lead-acid batteries,
The tips of the ears of each electrode plate constituting the electrode plate group are cut in the width direction, and the corners in the width direction of the tip of each electrode plate are chamfered, and the ears of each electrode plate are chamfered. A flat tip surface is formed at the center in the width direction of the tip and an inclined surface inclined with respect to the tip surface is formed at both ends in the width direction of the tip of each electrode plate,
The strap is cast in a state where a tip end surface and an inclined surface of an ear portion of the series of electrode plates are embedded therein, and a center in a width direction of an end portion of the strap facing the electrode plate group on the opposite side. Is formed so as to exhibit a shape in which corners at both ends in the width direction of the end portion are chamfered,
The flat portion of the strap and the portion having a chamfered shape are respectively opposed to the tip surface and the inclined surface of the ear portion embedded therein ,
The height h1 from the surface facing the electrode plate group side of the strap to the end of the inclined surface of the ear portion on the electrode plate group side, and the pole of the inclined surface of the strap from the surface facing the electrode plate group side of the strap The relationship of h2> h1 is established between the height h2 up to the end on the plate group side,
Lead acid battery characterized by.   The lead acid battery according to claim 2, wherein the chamfering of the corners at both ends in the width direction of the ear part and the chamfering of the corners at both ends in the width direction of the strap are C chamfering.

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