JP2021170429A - Positive electrode collector for lead storage battery and lead storage battery - Google Patents

Abstract

To provide a positive electrode collector for a lead storage battery and a lead storage battery, excellent in number of life cycle.SOLUTION: A positive electrode collector 21 for a lead storage battery includes a frame bone 22 and an inner bone 23 stretching inward of the frame bone 22. The positive electrode collector 21 has a Sn concentration of 1.1 wt.% or more. In the inner bone 23, the relationship of 0.4≤Y/X≤0.8 is satisfied, where Y represents a width in a first direction D1 that is a thickness direction of the positive electrode collector 21, and X represents a width in a second direction D2 that is perpendicular to the stretch direction of the inner bone 23 and the first direction D1, in a cross section perpendicular to the stretch direction.SELECTED DRAWING: Figure 4

Description

The present invention relates to a positive electrode current collector for a lead storage battery and a lead storage battery.

Lead-acid batteries are used for various purposes such as in-vehicle use and industrial use. The lead-acid battery includes a group of electrode plates in which a positive electrode plate and a negative electrode plate are alternately laminated via a separator. The positive electrode plate and the negative electrode plate are composed of a current collector and an electrode material held by the current collector.

For example, Patent Document 1 describes a positive electrode plate formed by filling a lattice portion of a current collector made of a Pb-Sb-based alloy, a Pb-Ca-based alloy, a Pb-Ca-Sn-based alloy, or the like with a paste-like active material. Is described. Further, Patent Document 1 describes a grid of a positive electrode current collector in which a corner portion of a cross section perpendicular to the stretching direction is deformed.

Japanese Unexamined Patent Publication No. 2017-139215

The inventors of the present application have conceived the present invention by paying attention to the fact that the positive electrode current collector corrodes and the positive electrode current collector is deformed when the lead storage battery is overcharged. That is, when the positive electrode current collector is corroded and deformed, a gap is generated between the positive electrode current collector and the positive electrode material. As a result, there is a problem that the positive electrode material falls off and the number of life cycles is reduced.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a positive electrode current collector for a lead storage battery and a lead storage battery having an excellent number of life cycles.

In order to solve the above problems, the positive electrode current collector for a lead storage battery according to the present invention is a positive electrode current collector for a lead storage battery including a frame bone portion and an inner bone portion extending inward of the frame bone portion. The positive electrode current collector has a Sn concentration of 1.1 mass% or more, and the inner bone portion is in the thickness direction of the positive electrode current collector in a cross section perpendicular to the extension direction of the inner bone portion. The width (Y) in the first direction and the width (X) in the stretching direction and the second direction perpendicular to the first direction satisfy the relationship of 0.4 ≦ Y / X ≦ 0.8.

According to the present invention, it is possible to provide a lead storage battery having an excellent number of life cycles.

It is a perspective view which shows the lead-acid battery 100 which concerns on embodiment of this invention. It is a figure which shows an example of the positive electrode current collector 21 which concerns on embodiment of this invention. FIG. 5 is a diagram schematically showing a cross section perpendicular to the stretching direction of the internal bone portion 23 in the positive electrode current collector 21 according to the embodiment of the present invention, and is a diagram showing a cross-sectional view taken along the line AA in FIG. It is a figure which shows the result of the light load life test which concerns on Example and comparative example of this invention.

[Embodiment]
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a perspective view showing a lead storage battery 100 according to an embodiment of the present invention. As shown in FIG. 1, the lead-acid battery 100 accommodates a plurality of electrode plate groups 11, an electrolytic solution (not shown), the electrode plate group 11, and an electrolytic solution, and has an electric tank 12 having an open upper portion and electricity. A lid 15 for sealing the opening of the tank 12 is provided.

The electric tank 12 is a substantially rectangular parallelepiped container having an opening 19 on the upper surface, and is formed of, for example, a synthetic resin. The battery case 12 has a partition wall 13. The inside of the electric tank 12 is partitioned by a partition wall 13 into a plurality of cell chambers 14 arranged in a predetermined direction.

One electrode plate group 11 is housed in each cell chamber 14 of the electric tank 12. Therefore, when the battery case 12 is partitioned into the six cell chambers 14, the lead-acid battery 100 includes six electrode plate groups. Further, each cell chamber 14 contains an electrolytic solution containing dilute sulfuric acid, and substantially the entire electrode plate group 11 is immersed in the electrolytic solution.

The opening 19 of the battery case 12 is sealed with a lid 15 having a shape corresponding to the opening 19. More specifically, the peripheral edge portion of the lower surface of the lid 15 and the peripheral edge portion of the opening 19 of the electric tank 12 are joined by, for example, heat welding. The lid 15 includes a negative electrode bushing 16 and a positive electrode bushing 17. Further, the lid 15 is provided with a liquid spout 18 at a position corresponding to each cell chamber 14. When refilling the lead-acid battery 100, the liquid spout 18 is removed and the refill liquid is replenished. The liquid spout 18 may have a function of discharging the gas generated in the cell chamber 14 to the outside of the lead storage battery 100.

The electrode plate group 11 is formed by laminating a plurality of negative electrode plates 2 and positive electrode plates 3 via a separator 4, respectively. Here, the bag-shaped separator 4 accommodating the negative electrode plate 2 is shown, but the form of the separator is not particularly limited. That is, the separator 4 does not have to be bag-shaped, and may accommodate the positive electrode plate 3.

The plurality of positive electrode plates 3 of the electrode plate group 11 are connected to a strap 6 formed of lead or a lead alloy. As a result, the plurality of positive electrode plates 3 are electrically connected in parallel via the strap 6. Similarly, the plurality of negative electrode plates 2 of the electrode plate group 11 are connected to a strap 6 formed of lead or a lead alloy. As a result, the plurality of negative electrode plates 2 are electrically connected in parallel via the strap 6. Further, the strap 6 is connected to each other by the adjacent cell chambers 14 through a through hole provided in the partition wall 13, whereby the electrode plate group 11 of the adjacent cell chambers 14 is directly connected to each other. There is.

In the cell chamber 14 located at the end of the battery case 12 on the positive electrode terminal side, the ears 26 (see FIG. 2) of the plurality of positive electrode plates 3 are connected to the substantially cylindrical positive electrode column 7 via the connecting member 5. ing. Similarly, in the cell chamber 14 located at the end of the battery case 12 on the negative electrode terminal side, the ears of the plurality of negative electrode plates 2 are connected to the negative electrode column 9 having a substantially cylindrical shape via the connecting member 5.

The positive electrode column 7 is inserted into the hole of the positive electrode bushing 17 of the lid 15 and is joined to the positive electrode bushing 17 by, for example, welding. The positive electrode column 7 and the positive electrode bushing 17 form a positive electrode terminal portion that functions as an external terminal. Further, the negative electrode column 9 is inserted into the hole of the negative electrode bushing 16 of the lid 15 and is joined to the negative electrode bushing 16 by, for example, welding. The negative electrode column 9 and the negative electrode bushing 16 form a negative electrode terminal portion that functions as an external terminal.

The negative electrode plate 2 has a negative electrode current collector and a negative electrode material supported by the negative electrode current collector. The negative electrode current collector is a conductive member having bones arranged in a substantially lattice pattern or a mesh pattern, and is formed of, for example, lead or a lead alloy. Further, the negative electrode current collector may be an expanded lattice, a cast lattice, or a punched lattice. Further, the negative electrode current collector has a negative electrode ear portion protruding upward near the upper end thereof. The negative electrode material contains lead (sponge-like lead). The negative electrode material may further contain other known additives (eg, carbon, graphite, lignin, barium sulfate, etc.).

The positive electrode plate 3 has a positive electrode current collector (positive electrode current collector for lead storage battery) 21 (see FIG. 2) and a positive electrode material supported by the positive electrode current collector. The positive electrode current collector 21 is a conductive member and is made of a lead alloy. The positive electrode material contains lead dioxide. The positive electrode material may further contain known additives.

FIG. 2 is a diagram showing an example of the positive electrode current collector 21 according to the present embodiment, and is a plan view of the positive electrode current collector 21 as viewed from the thickness direction. As shown in FIG. 2, the positive electrode current collector 21 is provided near the frame bone portion 22, the internal bone portion 23 extending inward of the frame bone portion 22, and the upper end of the frame bone portion 22, and projects upward. It has an ear portion 26 to be formed. The upper "upper" is the direction in which the selvage portion 26 protrudes from the frame bone portion 22 in the positive electrode current collector 21, and the lower "lower" is the opposite direction. That is, the vertical direction is the connection direction between the strap 6 and the ear portion 26 in the lead-acid battery 100. The horizontal direction is a direction perpendicular to the vertical direction.

The positive electrode current collector 21 has a frame bone portion 22 which is a frame-shaped member provided so as to surround the outer periphery of the region where the internal bone portion 23 is arranged. In the present embodiment, the frame bone portion 22 has a substantially rectangular shape. That is, the positive electrode current collector 21 includes frame bone portions 22 on four sides. The frame bone portion 22 includes an upper frame portion 22a, a lower frame portion 22b, a first vertical frame portion 22c, and a second vertical frame portion 22d.

The upper frame portion 22a is connected to the ear portion 26. Further, the upper frame portion 22a is provided so that when the lead storage battery 100 is mounted on an automobile or the like, the extension direction of the upper frame portion 22a is the horizontal direction. The lower frame portion 22b is provided so that the stretching direction is substantially parallel to the upper frame portion 22a.

The first vertical frame portion 22c is provided so as to connect the upper frame portion 22a and the lower frame portion 22b at one end of the upper frame portion 22a and the lower frame portion 22b in the extending direction. The second vertical frame portion 22d is provided so as to connect the upper frame portion 22a and the lower frame portion 22b at the other end of the upper frame portion 22a and the lower frame portion 22b.

The internal bone portion 23 is provided so as to extend inward of the positive electrode current collector 21 with respect to the frame bone portion 22, and includes a vertical bone portion 24 and a lateral bone portion 25. The vertical bone portion 24 extends so as to connect the upper frame portion 22a and the lower frame portion 22b, and extends substantially parallel to the first vertical frame portion 22c and the second vertical frame portion 22d. The configuration of the vertical bone portion 24 is not limited to this, and the vertical bone portion 24 may extend diagonally with respect to the first vertical frame portion 22c and the second vertical frame portion 22d. The vertical bone portion 24 may extend radially from a portion of the upper frame portion 22a connected to the ear portion 26 as a base point. When the vertical bone portion 24 extends diagonally or radially, the vertical bone portion 24 has the upper frame portion 22a or the lower frame portion 22b and the first vertical frame portion 22c or the second vertical frame portion 22d. It may extend to connect.

In the example shown in FIG. 2, the lateral bone portion 25 includes an oblique bone extending obliquely with respect to the upper frame portion 22a and the lower frame portion 22b, and a lateral bone extending substantially parallel to the upper frame portion 22a and the lower frame portion 22b. I have. However, the shape of the lateral bone portion 25 is not limited to this, and may include only diagonal bones or only lateral bones.

FIG. 3 shows a cross-sectional view taken along the line AA in FIG. 2, and schematically shows a cross section of the positive electrode current collector 21 according to the present embodiment, which is perpendicular to the extending direction of the internal bone portion 23. It is a figure. Here, the thickness direction of the positive electrode current collector 21 is defined as the first direction D1, and the extending direction of the internal bone portion 23 and the direction perpendicular to the first direction D1 are defined as the second direction D2. Further, the width of the internal bone portion 23 in the first direction D1 is defined as the first width Y, and the width of the internal bone portion 23 in the second direction D2 is defined as the second width X. The extension direction of the internal bone portion 23 is the extension direction of the internal bone portion 23 between the nodes which are the portions where the internal bone portions 23 intersect with each other. That is, in the example shown in FIG. 2, the extension direction of the vertical bone portion 24 is the vertical direction.

In the positive electrode current collector 21 according to the present embodiment, the first width Y and the second width X satisfy the relationship of the following formula (1).
0.4 ≤ Y / X ≤ 0.8 ... (1)

The first width Y and the second width X of the lead-acid battery 100 are measured as follows. First, the positive electrode current collector 21 is embedded in a thermosetting resin so that the entire prepared positive electrode current collector 21 is covered, and the resin is cured. Next, the positive electrode current collector 21 embedded in the resin is cut in a cross section perpendicular to the stretching direction of the internal bone portion 23. The cross section of the inner bone portion 23 of the cut positive electrode current collector 21 is photographed with a microscope or the like, and the first width Y and the second width X are calculated based on the photographed images. At this time, the first width Y and the second width X use the maximum values in the captured predetermined image. In other words, using the captured image, consider a rectangle circumscribing the internal bone portion 23, each side parallel to the first direction D1 or the second direction D2. The length of the side of the first direction D1 in the rectangle is defined as the first width Y, and the length of the side of the second direction D2 is defined as the second width X.

The shape of the cross section of the inner bone portion 23 of the positive electrode current collector 21 is not particularly limited as long as Y / X satisfies the above formula (1). That is, in FIG. 3, an example in which the cross-sectional shape is an octagonal shape is shown, but the cross-sectional shape may be another polygonal shape such as a quadrangle. Further, when the positive electrode current collector 21 is, for example, a cast lattice produced by casting or a punched lattice produced by punching a rolled sheet made of a lead alloy, the positive electrode current collector 21 is a positive electrode current collector. By adjusting the relationship between the thickness of 21 and the thickness of the crosspiece of the inner bone portion 23, Y / X can be set to a desired value. Further, the positive electrode current collector 21 which is a cast lattice or a punched lattice may be subjected to secondary processing such as press processing to change the shape of the cross section, so that Y / X may be set to a desired value.

In the present embodiment, the positive electrode current collector 21 is made of a lead alloy containing tin (Sn). The tin content of the positive electrode current collector 21 is preferably 1.1 mass% or more, preferably 1.1 mass% or more and 1.8 mass% or less. The tin amount of the positive electrode current collector 21 can be measured by using a known method, and can be analyzed by, for example, ICP (Inductively Coupled Plasma) emission spectroscopy. Further, the positive electrode current collector 21 may further contain elements other than lead and tin. For example, it may be a Pb-Ca-Sn-based alloy. In the case of the Pb-Ca-Sn system, Ca is preferably in the range of 0.06 mass% to 0.08 mass%. Further, the positive electrode current collector 21 may contain one or more elements selected from the group consisting of Ca, Ba, Ag, Al, Bi, As, Se and Cu.

The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and the embodiments obtained by appropriately combining the technical means disclosed in the different embodiments. Is also included in the technical scope of the present invention.

〔summary〕
(1) The positive electrode current collector for a lead storage battery according to one aspect of the present invention is a positive electrode current collector for a lead storage battery including a frame bone portion and an inner bone portion extending inward of the frame bone portion. The positive electrode current collector has a Sn concentration of 1.1 mass% or more, and the inner bone portion is in the first direction which is the thickness direction of the positive electrode current collector in the cross section perpendicular to the extending direction of the inner bone portion. The width (Y) of the above and the width (X) in the second direction perpendicular to the stretching direction and the first direction satisfy the relationship of 0.4 ≦ Y / X ≦ 0.8.

In general, it is known that when a lead-acid battery is overcharged, the positive electrode current collector of the lead-acid battery is corroded and the positive electrode current collector is deformed. When the positive electrode current collector is corroded and deformed, a gap is created between the positive electrode current collector and the positive electrode material, and the positive electrode material supported by the positive electrode current collector is separated from the positive electrode current collector. However, it may drop out. As described above, there is a problem that the number of life cycles of the lead storage battery is reduced due to the removal of the positive electrode material.

According to the above configuration, the positive electrode current collector for a lead storage battery according to one aspect of the present invention is a positive electrode current collector whose inner bone portion satisfies the relationship of 0.4 ≦ Y / X ≦ 0.8. , Sn concentration is 1.1 mass% or more. As described above, by setting the Sn concentration in the positive electrode current collector to 1.1 mass% or more, the effect of improving the corrosion resistance by Sn is produced, and when the lead storage battery includes the positive electrode current collector, the positive electrode current collector is provided. Corrosion during overcharging can be suppressed. This effect is particularly remarkable when the shape of the cross section perpendicular to the stretching direction of the inner bone portion of the positive electrode current collector is shaped so as to satisfy the relationship of 0.4 ≦ Y / X ≦ 0.8. In other words, by controlling the shape of the cross section of the internal bone portion 23 so as to satisfy 0.4 ≦ Y / X ≦ 0.8, the effect of suppressing corrosion of the positive electrode current collector by Sn is remarkable. Can be. In this way, by suppressing the corrosion of the positive electrode current collector during overcharging, it is possible to suppress the removal of the positive electrode material during overcharging when used in a lead-acid battery, and the number of life cycles is increased. An excellent lead-acid battery can be provided.

In the positive electrode current collector according to one aspect of the present invention, it is not necessary to satisfy the relationship of 0.4 ≦ Y / X ≦ 0.8 at all places of the internal bone portion. That is, it is sufficient that the relationship of 0.4 ≦ Y / X ≦ 0.8 is satisfied at least in a part of the internal bone portion. More specifically, it is included in the present invention as long as the relationship of 0.4 ≦ Y / X ≦ 0.8 is satisfied in at least 10 different inner bones among the inner bones.

Further, the positive electrode current collector used for calculating Y / X may be one before the positive electrode material is filled, or may be one taken out by disassembling the lead storage battery. In the latter case, first, the lead-acid battery is disassembled and the positive electrode plate taken out is washed with water to remove the electrolytic solution containing sulfuric acid. Next, the positive electrode plate is dried and the positive electrode material is removed from the positive electrode plate. Next, the positive electrode current collector from which the positive electrode material has been removed is immersed in an alkaline mannit solution for a predetermined time and then washed with water to cause the positive electrode material and corrosion products adhering to the surface of the positive electrode current collector. Is further removed. Then, Y / X is calculated by boiling the positive electrode current collector from which the positive electrode material and the corrosion product have been removed.

In the positive electrode current collector according to one aspect of the present invention, the "frame bone portion" is limited to a rectangular shape provided so as to form the outer circumference of the positive electrode current collector as shown in FIG. It's not a thing. That is, the "frame bone portion" of the present invention also includes an upper frame portion connected to the ear and a lower frame portion provided so as to face the upper frame portion, such as an expanding lattice. In other words, the frame bone portion of the positive electrode current collector may not include the lower frame portion, the first vertical frame portion, and / or the second vertical frame portion. Further, each of the upper frame portion, the lower frame portion, the first vertical frame portion, and the second vertical frame portion does not necessarily have to be continuously provided with a uniform thickness. That is, the upper frame portion, the lower frame portion, the first vertical frame portion, and the second vertical frame portion may be partially provided with a notch, or the width may be partially changed.

(2) The lead-acid battery current collector according to one aspect of the present invention may be provided so that the frame bone portion surrounds the outer periphery of the region where the inner bone portion is arranged.

According to the above configuration, when the positive electrode current collector includes a frame bone portion provided so as to surround the outer periphery of the inner bone portion, when the positive electrode current collector is corroded, the positive electrode current collector is collected. The body is liable to be deformed so as to be curved in the thickness direction of the positive electrode current collector. This is because the frame bone is provided in all directions of the outer circumference when the positive current collector corrodes and the internal bone is deformed, so that the internal bone is the frame bone. It is considered that this is because the deformation that curves in the thickness direction is more likely to occur than the deformation that extends in the outer peripheral direction.

On the other hand, when the positive electrode current collector is an expanded lattice manufactured by a known rotary method, the positive electrode current collector includes only an upper frame portion and a lower frame portion, and includes a vertical frame portion. No. As described above, when the positive electrode current collector does not include the frame bone portion 22 provided so as to surround the outer periphery of the inner bone portion, even if the positive electrode current collector is corroded, the positive electrode current collector can be used. The positive electrode current collector can be deformed in a plane perpendicular to the thickness direction of the positive electrode current collector, and the positive electrode current collector is less likely to be curved in the thickness direction. In this way, when the positive electrode current collector is deformed in a plane perpendicular to the thickness direction of the positive electrode current collector, the positive electrode electrode is compared with the case where the positive electrode current collector is deformed in the thickness direction. Material is less likely to fall off.

Therefore, when the positive electrode current collector is provided with a frame bone portion provided so as to surround the outer periphery of the inner bone portion that is likely to be deformed so as to be curved in the thickness direction of the positive electrode current collector, the positive electrode current collector is provided. When the body satisfies the relationship of 0.4 ≦ Y / X ≦ 0.8 and the Sn concentration is 1.1 mass% or more, deformation such as bending in the thickness direction of the positive electrode current collector is unlikely to occur. Compared with the case where the frame bone portion provided so as to surround the outer periphery of the inner bone portion is not provided, the effect of suppressing the falling off of the positive electrode electrode material can be further increased.

(3) The positive electrode current collector for a lead storage battery according to one aspect of the present invention may be a punched lattice.

According to the above configuration, when the positive electrode current collector for a lead storage battery is a punched lattice, the effect of suppressing the falling off of the positive electrode material is greater than that of a cast lattice or an expanded lattice. That is, in the production of the punched lattice, first, a slab made of cast lead or a lead alloy is rolled to produce a rolled sheet. Next, a punching lattice is produced by punching the produced rolled sheet. Therefore, the surface roughness of the surface (rolled surface) perpendicular to the thickness direction of the positive electrode current collector that comes into contact with the rolling roll becomes small. Here, the positive electrode material mainly comes into contact with a surface perpendicular to the thickness direction of the positive electrode current collector. Therefore, since the surface roughness of the surface of the current collector that mainly contacts the positive electrode material is small, the adhesion between the positive electrode current collector and the positive electrode material is not good in the punched lattice.

Further, in the rolled sheet, crystal grains are stretched in the rolling direction (the transport direction of the rolled sheet during rolling) during rolling, and a layered structure in which metal structures are laminated in the thickness direction of the rolled sheet is formed. Then, on the rolled surface, since the crystal grain boundaries extend in the direction parallel to the rolled surface rather than the depth direction, the corrosion on the rolled surface proceeds in layers from the surface layer. Here, the corroded layer formed by the corrosion of the positive electrode current collector has good adhesion to the positive electrode material, and has a function of bringing the positive electrode current collector and the positive electrode material into close contact with each other. In the punched lattice, the corrosive layer is selectively formed on the surface layer of the positive electrode current collector. Therefore, when the positive electrode current collector is deformed by corrosion, the corroded layer formed on the surface layer of the positive electrode current collector is the positive electrode. By peeling from the current collector in layers, the adhesion between the positive electrode current collector and the positive electrode material is lost. Therefore, in the punched lattice in which the corrosive layer is selectively formed on the surface layer of the positive electrode current collector, the positive electrode current collector and the positive electrode are compared with the case where the corrosive layer is formed in the thickness direction of the positive electrode current collector. A gap is likely to occur between the electrode material and the electrode material. As described above, in the punched lattice, the adhesion between the positive electrode current collector and the positive electrode material is not good, and when the positive electrode current collector is deformed, the positive electrode material tends to fall off.

On the other hand, considering the case where the positive electrode current collector is a cast lattice, a mold release material is applied to the cast lattice so that the current collector can be easily released from the mold in the manufacturing process. Therefore, due to the influence of the mold release material, the surface roughness of the surface of the cast lattice (the surface perpendicular to the thickness direction of the positive electrode current collector) in contact with the positive electrode material is larger than that of the punched lattice. Further, in the cast lattice, the crystal grains are larger than those of the rolled sheet. Therefore, when the positive electrode current collector is corroded, intergranular corrosion occurs and the corrosion progresses to the inside of the positive electrode current collector. When the corroded layer is formed to the inside, even if the positive electrode current collector is deformed due to corrosion, the corroded layer formed to the inside becomes a wedge, ensuring the adhesion between the positive electrode current collector and the positive electrode material. do. Therefore, in the cast lattice, a gap is unlikely to occur between the positive electrode current collector and the positive electrode material. As described above, the cast lattice has a larger surface roughness than the punched lattice and a corrosive layer is formed to the inside, so that the cast lattice has better adhesion to the positive electrode material than the punched lattice.

Further, although the expanded lattice uses a rolled sheet like the punched lattice, the inner bone of the lattice is twisted in the manufacturing process. Therefore, in the expanding lattice, the surface perpendicular to the rolling direction is exposed to the surface perpendicular to the thickness direction of the lattice. Therefore, in the expanding lattice, the positive electrode material comes into contact with both the rolled surface and the surface perpendicular to the rolling direction. The surface perpendicular to the rolling direction has grain boundaries extending deeper in the depth direction than the rolled surface. Here, since the surface perpendicular to the rolling direction has grain boundaries extending deeply from the rolled surface in the depth direction and intergranular corrosion occurs, a corrosive layer is formed in the depth direction as in the case of the casting lattice. NS. Therefore, the surface perpendicular to the rolling direction has better adhesion to the positive electrode material than the rolled surface. That is, in the expanding lattice, the surface perpendicular to the rolling direction, which has good adhesion to the positive electrode material, is exposed to the surface perpendicular to the thickness direction of the positive electrode current collector, which is required to have adhesion to the positive electrode material. .. For the above reasons, the expanded lattice also has better adhesion to the positive electrode material than the punched lattice.

From the above, in the punched lattice where the adhesion to the positive electrode material is not as good as that of the cast lattice or the expanded lattice, the positive electrode current collector satisfies the relationship of 0.4 ≦ Y / X ≦ 0.8 and the Sn concentration is high. When it is 1.1 mass% or more, the effect of suppressing the dropout of the positive electrode material can be further increased as compared with the cast lattice and the expanded lattice.

(4) The positive electrode current collector for a lead storage battery according to one aspect of the present invention may have a Sn concentration of 1.8 mass% or less.

(5) A lead-acid battery including a current collector for a lead-acid battery according to one aspect of the present invention is also included in the present invention.

[Examples and Comparative Examples]
Hereinafter, embodiments of the present invention will be described in more detail based on Examples and Comparative Examples. However, the present invention is not limited to the following examples.

(Manufacturing of positive electrode plate)
First, the first width Y / second by punching a rolled sheet of a Pb-0.07 mass% Ca-Sn based alloy having Sn concentrations of 0.5 mass%, 1.1 mass%, and 1.8 mass%. A positive electrode current collector of a punched lattice having a width X in the range of 0.2 to 0.9 is produced. Next, the positive electrode paste containing lead powder is prepared and filled in the positive electrode current collector. Then, it is aged and dried to obtain an unchemical positive electrode plate.

(Manufacturing of negative electrode plate)
The negative electrode paste is prepared by mixing lead powder, water, dilute sulfuric acid, barium sulfate, carbon black, graphite, and an organic shrink proofing agent (sodium lignin sulfonate). As a negative electrode current collector, an expanding lattice made of a Pb—Ca—Sn alloy is filled with a negative electrode paste. Then, it is filled and dried to obtain an unchemical negative electrode plate.

(Making lead-acid batteries)
Each unchemical negative electrode plate is housed in a polyethylene bag-shaped separator. Next, seven unchemicald negative electrode plates and seven unchemicald positive electrode plates are alternately stacked per cell to prepare a group of electrode plates. Then, the prepared six electrode plates are inserted into each cell chamber of the polypropylene electric tank, and the electrolytic solution is injected. Next, chemical conversion is performed in the battery case to assemble a liquid lead-acid battery. An aqueous sulfuric acid solution is used as the electrolytic solution.

(Light load life test)
A high-temperature overcharge test is performed on the produced lead-acid battery according to the following procedure.
In order to make the overcharge condition more than the normal 4-minute-10-minute test specified by JIS D5301, a 1-minute discharge-10-minute charge test (1-10-minute test) was performed in a 75 ° C atmosphere. CCA performance is determined every 610 cycles. The method for determining CCA performance conforms to the provisions of JIS D5301. The discharge conditions and charge conditions are as follows.
Discharge: 25A, 1 minute Charge: 14.8V, 25A, 10 minutes When the CCA performance is judged, the life is judged when the discharge voltage drops to 7.2V or less. Further, when the charging current is abnormally increased during charging in the cycle test, it is determined that the product has reached the end of its life. The number of cycles determined to have reached the end of its life is defined as the number of life cycles.

FIG. 4 is a diagram showing the results of a high temperature overcharge test according to Examples and Comparative Examples, and is a diagram showing the relationship between the first width Y / second width X and the number of life cycles. In FIG. 4, the result is shown with the life cycle of a lead storage battery using a positive electrode current collector having a first width Y / second width X of 0.2 and Sn of 0.5 mass% as 100%. ..

As can be seen from FIG. 4, a lead-acid battery having a positive electrode current collector having a Sn of 1.1 mass% or more has a higher temperature overcharge test than a lead-acid battery having a positive electrode current collector having a Sn of less than 1.1 mass%. It can be seen that the number of life cycles is excellent. This tendency is particularly remarkable in the range where Y / X is 0.4 or more and 0.8 or less.

21: Positive electrode current collector (positive electrode current collector for lead storage battery) 22: Frame bone part 23: Inner bone part 100: Lead storage battery D1: 1st direction D2: 2nd direction Y: 1st width X: 2nd width

Claims (5)

A positive electrode current collector for a lead storage battery including a frame bone portion and an inner bone portion extending inward of the frame bone portion.
The positive electrode current collector has a Sn concentration of 1.1 mass% or more.
The inner bone portion is perpendicular to the width (Y) in the first direction, which is the thickness direction of the positive electrode current collector, and the stretching direction and the first direction in a cross section perpendicular to the extending direction of the inner bone portion. A positive electrode current collector for a lead storage battery, wherein the width (X) in the second direction satisfies the relationship of 0.4 ≦ Y / X ≦ 0.8. The positive electrode current collector for a lead storage battery according to claim 1, wherein the frame bone portion is provided so as to surround the outer periphery of the region where the inner bone portion is arranged. The positive electrode current collector for a lead storage battery according to claim 1 or 2, wherein the positive electrode current collector is a punched lattice. The positive electrode current collector for a lead storage battery according to any one of claims 1 to 3, wherein the positive electrode current collector has a Sn concentration of 1.8 mass% or less. A lead-acid battery comprising the positive electrode current collector according to any one of claims 1 to 4.

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