JP2021103630A - Collector for storage battery and electrode plate - Google Patents

Abstract

SOLUTION: The present invention relates to a collector for storage battery comprising a frame body, an ear provided in the frame body, and an inner bone inside of the frame body. The frame body includes a first frame bone continued to the ear, a second frame bone opposed with the first frame bone, and a pair of side frame bones connecting the first frame bone and the second frame bone. The inner bone includes an oblique bone crossing both a first direction from the first frame bone to the second frame bone and a second direction from one side frame bone to the other side frame bone. A stripe pattern of fibrous tissues of a metal is observed on a cross section C of the oblique bone vertical to the second direction. An outer peripheral region of the cross section C is constituted of a first portion in which the fibrous tissues extend along a contour of the cross section C, and a second portion other than the first portion. When a percentage of a length of a portion corresponding to the second portion occupied in a full length of the contour of the cross section C is defined as r1% and a ratio Σs/S of an integrated value Σs of a projection area (s) of the oblique bone in the second direction with respect to a projection area S of the side frame bone in the second direction is defined as r2, a product R1 of r1 and r2 is equal to or less than 110%.SELECTED DRAWING: Figure 1

Description

The present invention relates to a current collector for a storage battery and an electrode plate.

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 positive electrode plates and negative electrode plates are alternately laminated via separators. The electrode plate is composed of a current collector and an electrode material held by the current collector.

Patent Document 1 describes a rectangular frame bone, an ear portion protruding from the first side of the four sides of the frame bone to the outside of the frame, and a second side facing the first side portion and the first side portion. A main bone connecting the portions, and a plurality of first sub-bones branching from at least the main bone, extending bilaterally with the main bone as an axis, and extending diagonally toward the second side. The present invention proposes a storage battery lattice in which at least a part of the plurality of first sub-bones is bent.

Japanese Unexamined Patent Publication No. 2014-235844

When the storage battery lattice of Patent Document 1 is used, it is possible to improve the mechanical strength of the lattice and reduce the electric resistance of the lattice to make the potential distribution in the storage battery lattice uniform. However, as the corrosion of the storage battery grid progresses, the elongation of the storage battery grid tends to be remarkable.

One aspect of the present invention includes a frame body, an ear provided on the frame body, and an inner bone inside the frame body, and the frame body has a first frame bone continuous with the ear. A second frame bone facing the first frame bone and a pair of side frame bones connecting the first frame bone and the second frame bone are provided, and the internal bone is the first frame bone. The oblique bone comprising an oblique bone that intersects with both the first direction from the frame bone to the second frame bone and the second direction from one said side frame bone to the other said side frame bone. In the cross section perpendicular to the second direction, a striped pattern of metal fibrous structure is seen, and the outer peripheral region of the cross section includes a first portion in which the fibrous structure extends along the contour of the cross section and the first portion. The percentage of the length of the portion corresponding to the second portion to the total length of the contour of the cross section, which is composed of the second portion other than the above, is r1%, and the side frame bone is in the second direction. When the ratio of the integrated value Σs of the projected area s of the diagonal bone in the second direction to the projected area S: Σs / S is r2, the product of r1 and r2: R1 is 110% or less. Regarding the current collector for storage batteries.

According to the present invention, elongation due to corrosion of the current collector for a storage battery is suppressed.

It is a top view which shows the appearance of the current collector for a lead storage battery which concerns on one Embodiment of this invention. It is a photograph of the cross section C perpendicular to the second direction of the oblique bone. It is a conceptual diagram of the cross section C. It is a conceptual diagram of the cross section C which shows the progress state of the corrosion of an oblique bone. It is a conceptual diagram of the cross section G1 perpendicular to the extending direction of a transverse bone. It is a conceptual diagram of the cross section G2 perpendicular to the extending direction of a vertical bone. It is a perspective view which shows the appearance of the lead storage battery which concerns on one Embodiment of this invention. It is a graph which shows the relationship between the width elongation and height elongation of a current collector, and R1.

The lead-acid battery current collector according to one aspect of the present invention has a frame body, ears provided on the frame body, and an inner bone inside the frame body. The frame body includes a first frame bone continuous with the ear, a second frame bone facing the first frame bone, and a pair of side frame bones connecting the first frame bone and the second frame bone. .. The internal bone comprises an oblique bone that intersects both the first direction from the first frame bone to the second frame bone and the second direction from one side frame bone to the other side frame bone. The current collector is also referred to as a lattice body.

The frame is usually generally rectangular and may be rectangular. The quadrangle is 90 at least one of the angles formed by the first frame bone and the pair of side frame bones and the angles formed by the second frame bone and the pair of side frame bones (total of four angles). It may be a quadrangle (for example, a trapezoid) other than °. At least one of the four corners of the quadrangle may be chamfered. The chamfer may be C chamfer or R chamfer. Usually, R chamfering with rounded corners is preferable.

When the frame is rectangular, the first direction is the direction parallel to the lateral frame bone, and the second direction is the direction parallel to the first frame bone and the second frame bone. In the case of a liquid-type lead-acid battery in which the frame is a quadrangle other than a rectangle, the first direction corresponds to the vertical direction and the second direction corresponds to the horizontal direction in the normal usage state of the lead-acid battery. In the case of a control valve type lead-acid battery in which the frame is a quadrangle other than a rectangle, the first direction corresponds to the vertical direction (or the horizontal direction) and the second direction is horizontal in the normal usage state of the lead-acid battery. Corresponds to the direction (or vertical direction).

The oblique bone intersects both the first and second directions. Since the inner bone has an oblique bone, the electrical resistance of the current collector can be reduced and the potential distribution in the current collector can be made uniform. However, the first direction and the direction less than 15 ° are regarded as the first direction. Further, the second direction and the direction less than 15 ° are regarded as the second direction. That is, the oblique bone means an internal bone that intersects at an angle of 15 ° or more in both the first direction and the second direction. The angle between the oblique bone and the first direction and the second direction is the angle between the extension direction of the oblique bone and the first direction and the second direction. The extension direction of the oblique bone is the extension direction of the line segment connecting both ends of the oblique bone.

The internal bone may have only an oblique bone, but may have a longitudinal bone extending in the first direction, or a transverse bone extending in the second direction. For example, the internal bone may be at least reticulated with vertical and diagonal bones. In this case, the internal bone may or may not have a lateral bone. Specifically, the internal bone may have a mesh shape having only vertical bones and diagonal bones, or may have a mesh shape having vertical bones, diagonal bones, and lateral bones.

In the cross section perpendicular to the second direction of the oblique bone (hereinafter, referred to as cross section C), a striped pattern of metal fibrous tissue can be seen. The outer peripheral region of the cross section C is composed of a first portion in which the fibrous structure (direction of stripes) extends along the contour of the cross section C and a second portion other than the first portion.

The contour of the cross section C means a line corresponding to the outer surface of the oblique bone. The outer peripheral region of the cross section C is a peripheral region along the contour of the cross section C, and is a peripheral region having a depth of at least 55 μm or more, preferably 100 μm or more from the line corresponding to the outer surface. In the second portion, the striped pattern may not be observed, and the striped pattern extending in the depth direction of the outer peripheral region may be observed.

In the second part, a cross section perpendicular to the fiber length of the fibrous structure can be exposed. The cross section of the fibrous structure perpendicular to the fiber length has many grain boundaries. In general, the corrosion of the current collector proceeds preferentially at the grain boundaries exposed on the outer surface. In the second part, the fibrous tissue extends in the depth direction of the internal bone, and the grain boundaries also extend in the depth direction of the internal bone. Therefore, in the second part, the corrosion of the oblique bone tends to proceed deeply in a wedge shape. The deep corrosive layer formed in the second portion easily applies stress to the internal bone and deforms the internal bone. The larger the proportion of the second portion, the greater the elongation of the current collector due to the corrosion of the oblique bone.

On the other hand, in the first portion, the fibrous tissue extends in the plane direction of the internal bone, and the grain boundaries also extend in the plane direction of the internal bone. Therefore, the corrosive layer formed in the first portion is formed along the surface direction of the internal bone, and is difficult to be formed to a deep position inside the internal bone. In the first part, the corrosion of the oblique bone tends to progress shallowly, and the elongation of the current collector due to the shallow corrosion is small.

In principle, the current collector can be stretched in the first direction (height stretch) and stretched in the second direction (width stretch). However, due to the structure of the lead-acid battery, both ends of the current collector in the first direction have a small degree of freedom, so that the height extension in the first direction is suppressed. Therefore, it is important to suppress the width elongation in the second direction.

In the cross section perpendicular to the stretching direction (that is, the second direction) of the lateral bone (hereinafter, referred to as cross section G1), almost no striped pattern of metal fibrous structure is observed, and generally, the fibrous structure is observed. A cross section perpendicular to the fiber length can be seen. The outer peripheral region of the cross section G1 is composed of a fibrous structure whose entire circumference extends in the second direction. Therefore, the corrosion of the lateral bone does not contribute much to the elongation of the current collector.

In the cross section (hereinafter referred to as cross section G2) perpendicular to the stretching direction (that is, the first direction) of the longitudinal bone, a striped pattern of metal fibrous structure is observed, and the outer peripheral region of the cross section G2 is a considerable proportion of the first. It has two parts. As the corrosion of the vertical bone progresses, the current collector tends to extend in the first direction, but the height extension in the first direction is suppressed due to the structure of the lead-acid battery.

On the other hand, the oblique bone has a first direction component (vertical vector) and a second direction component (horizontal vector). Corrosion caused by the first-direction component does not contribute to the suppressed height elongation in the first direction, but contributes to the elongation of the second-direction component. That is, the presence of diagonal bones tends to increase the width elongation in the second direction. It can be said that the width extension in the second direction is a problem peculiar to the current collector having an oblique bone.

Here, the percentage of the length of the portion corresponding to the second portion (that is, the ratio of the second portion) to the total length of the contour of the cross section C is set to r1%. Further, the ratio of the integrated value Σs of the projected area s of the oblique bone in the second direction to the projected area S of the lateral frame bone in the second direction: Σs / S is set to r2. At this time, by setting R1 defined by the product of r1 and r2 (r1 × r2) to 110% or less, elongation due to corrosion of the current collector is suppressed. When R1 exceeds 110%, the width elongation of the current collector suddenly becomes remarkable and the height elongation of the current collector also becomes apparent. When R1 exceeds 110% and the contribution of the oblique bone becomes so large that it becomes difficult to suppress height elongation due to structural restrictions, the stress accumulated in the current collector due to corrosion is extended by the current collector. The need for mitigation increases. Width elongation and height elongation contribute to stress relief. Structurally, the elongation in the second direction can proceed more easily than in the first direction, so that it is considered that the degree of width elongation increases. The integrated value Σs is an index of the magnitude of the integrated value of the first-direction components of all the oblique bones. R1 may be 110% or less, 40% or less, or 25% or less.

The smaller the percentage (percentage of the second part) r1, the more desirable it is. For example, it may be 40% or less, 20% or less, or 10% or less. However, when the current collector is a punched lattice obtained by punching an alloy sheet, it is usually difficult to make it smaller than 5%. When r1 is 5% or more, grain boundaries of a metal structure that can affect the elongation of the current collector are exposed on the outer surface of the oblique bone.

It is considered that the larger r2 (Σs / S), the greater the effect of reducing the electric resistance of the current collector and the effect of making the potential distribution uniform. In order to obtain a significant effect, it is desired that at least r2 is 1.6 or more, and further 2.0 or more (for example, 2.1 or more). However, if r2 is too large, the elongation due to corrosion of the current collector becomes large, so that r2 is preferably 2.6 or less. On the other hand, when R1 is 110% or less (for example, 102% or less) or 40% or less (for example, 39% or less), the elongation due to corrosion of the current collector is effectively enjoyed while enjoying the merits of the oblique bone. It can be suppressed and the dropout of the electrode material can be remarkably reduced.

The smaller R1 is, the more the elongation due to corrosion of the current collector is suppressed, but the contribution of the oblique bone is reduced by that amount, and it is difficult to obtain the effect of reducing the electrical resistance of the current collector and the effect of equalizing the potential distribution. Become. In order to secure a sufficient contribution of the oblique bone, R1 is preferably 20% or more, for example.

Further, the ratio of the oblique bone to the internal bone other than the vertical bone (that is, the ratio of the total length of the oblique bone to the total length of the oblique bone and the lateral bone) is preferably 50% or more, and 70% or more. More preferably, it may be 100%.

When calculating the total length of each internal bone, the parts other than the intersection (node) where different bones intersect are integrated.

R1 can be controlled by selecting r1 and r2. r1 and r2 can be controlled, for example, by deforming the internal bone by press working. The change in r1 can also be controlled by, for example, the speed of the press, the press pressure, the shape of the die, and the like. Deformation of the internal bone by press working is not enough to change r1. It is necessary to appropriately control the pressing conditions.

The ratio R2 of the thickness of the internal bone to the thickness of the lateral frame bone may be 78 to 95%, 78 to 90%, or 78 to 85%. By changing R2, r1 and r2 also change. Therefore, R1 can be controlled by R2. The thickness of the frame bones constituting the frame body is usually constant, and the thickness of the internal bones is also constant. If the thickness of each bone varies, the average thickness may be used. The average thickness may be obtained by a common sense or a general method, but may be calculated as, for example, the average value of the thicknesses at any 10 points.

More specifically, the thickness of the internal bone may be, for example, 0.7 mm to 3 mm. The bone width of the internal bone may be, for example, 0.7 mm to 3 mm. Bone width refers to the bone width perpendicular to the extension direction of the internal bone.

The lead-acid battery current collector according to one aspect of the present invention can be produced by a method including pressing an intermediate bone which is a precursor of an internal bone. Such a manufacturing method is, for example, an intermediate lattice body having a plurality of intermediate bones formed in a grid pattern by (i) a step of preparing a rolled plate and (ii) a punching process on the rolled plate. (Iii) includes a step of forming at least a part of the inner bone by pressing the intermediate lattice body from the thickness direction of the intermediate lattice body. Here, in the press working, at least a part of the plurality of intermediate bones is deformed so that at least one end in the bone width direction is thinner than the central portion in the bone width direction intersecting the extending direction of the intermediate bones. You may.

(How to find r1)
First, any five points of the diagonal bone of the current collector are cut perpendicularly to the second direction of the diagonal bone to form ten cross sections C. Of the outer peripheral region of the cross section C, the portion where the fringes of the fibrous structure has an angle of less than 45 ° with the contour of the cross section C is the first portion. Specifically, at an arbitrary point P on the contour of each cross section C, a tangent line S1 of the point P is drawn, and a perpendicular line L of the tangent line S1 is drawn so as to pass through the point P. Next, a tangent line S2 of a stripe existing at a depth of 55 μm from the point P on the perpendicular line L and intersecting the perpendicular line L is drawn at the intersection. When the angle θ between the tangent line S2 and the tangent line S1 is less than 45 °, the point P constitutes the contour portion corresponding to the first portion. Such observation is appropriately performed on the contour of the cross section C, the length of the contour portion corresponding to the first portion is specified, and the length is subtracted from the total length of the contour to obtain the length of the contour portion corresponding to the second portion. Ask. Then, the ratio of the contour portion corresponding to the second portion to the total length is calculated as r1. When the angle θ is 45 ° or more, the point P constitutes the contour portion corresponding to the second portion. Even when it is not possible to determine whether or not the point P corresponds to the first portion due to reasons such as the fibrous structure not being observable, the point P shall constitute the second portion. In each of the 10 cross sections C, r1 is obtained and the average value is calculated.

When forming the cross section C, a current collector before filling the electrode material may be used. Alternatively, a current collector taken out from a fully charged lead-acid battery may be used. That is, the fully charged lead-acid battery is disassembled, the electrode plate is taken out, washed with water to remove the electrolytic solution, and dried. After embedding in a thermosetting resin so as to cover the entire prepared current collector and curing the resin, the current collector may be cut together with the cured resin. The state of the metal structure in the cross section C may be observed by etching the cross section of the current collector and then photographing it with a microscope.

A fully charged lead-acid battery is a fully charged lead-acid battery. The lead-acid battery may be fully charged after the chemical conversion, immediately after the chemical conversion, or after a lapse of time from the chemical conversion. For example, the lead-acid battery in use (preferably in the initial stage of use) may be fully charged after chemical conversion. An initial use battery is a battery that has not been used for a long time and has hardly deteriorated.

In the present specification, the fully charged state of the lead-acid battery means that in the case of a liquid battery, the current (A) is 0.2 times the value described as the rated capacity (Ah) in a water tank at 25 ° C. ± 2 ° C. After constant current charging until reaching 2.5 V / cell, constant current charging was performed for 2 hours at a current (A) 0.2 times the value described as the rated capacity (Ah). .. Further, in the case of a control valve type battery, the fully charged state is a current (A) 0.2 times the value described as the rated capacity (Ah) in an air tank at 25 ° C. ± 2 ° C. It is in a state of being charged at a constant current and constant voltage of 23 V / cell, and when the charging current (A) at the time of constant voltage charging becomes 0.005 times the value described as the rated capacity (Ah), the charging is completed. The numerical value described as the rated capacity is a numerical value in which the unit is Ah. The unit of current set based on the numerical value described as the rated capacity is A.

The thickness of the first portion may be 55 μm or more. Further, even if the outer peripheral region looks like the first portion at first glance, if the thickness of the region where the striped pattern of the fibrous structure is observed is less than 55 μm, it is regarded as the second portion instead of the first portion. The first portion having a thickness of 55 μm or more has a sufficient effect of suppressing the intrusion of corrosion into the inside. The thickness of the first portion is preferably 100 μm or more from the viewpoint of further improving the suppression of the vertical bone corrosion from entering the inside.

The thickness of the first portion in the cross section C may be measured as follows. First, a tangent line S1 is drawn at an arbitrary point P1 on the contour portion corresponding to the first portion, and a perpendicular line L of the tangent line S1 is drawn so as to pass through the point P1. Next, at the point Px that moves on the perpendicular line L from the point P1 to a depth of X μm, the tangent line S2 of the stripe that intersects the perpendicular line L is continuously drawn. At this time, when the angle between the tangent line S1 and the tangent line S2 is continuously 45 ° or less, it can be said that the thickness of the first portion immediately below the point P1 is X μm or more.

(How to find r2)
First, the projected area S of the side frame bone of the current collector in the second direction is obtained. The projected area S usually corresponds to the product of the thickness of the lateral frame bone and the length of the lateral frame bone in the first direction. If the thickness of the lateral frame bone changes, the average thickness may be used. The average thickness may be obtained by a common sense or a general method, but may be calculated as, for example, the average value of the thicknesses at any 10 points. The length of the lateral frame bone in the first direction is the length obtained by subtracting the length of the first frame bone and the second frame bone in the first direction from the length (height) of the current collector in the first direction. That's right. Here, the ears are not included in the height of the current collector in the first direction.

Next, the projected area s of all the oblique bones in the second direction is obtained. At this time, the projected area of the portion other than the intersection (node) where different bones intersect is integrated. Specifically, the oblique bone has two sides that intersect both the first and second directions. One side of the oblique bone faces one side of the lateral frame bone, and the other side of the oblique bone faces the other side of the lateral frame bone. The two sides correspond to the cut surfaces formed by the punching process when the current collector is a punched grid. The areas of the two sides (cut surfaces) can be considered the same. One of the side surfaces is selected, and the projected area on the side frame bone facing the side surface is obtained as the projected area s of the diagonal bone. Then, the sum of the projected areas of all the oblique bones is calculated as Σs, and the ratio of Σs to S is calculated as r2.

Hereinafter, embodiments of the present invention will be further described with reference to the drawings.
FIG. 1 is a plan view showing the appearance of the current collector 100 according to the embodiment of the present invention. Each of the current collectors 100 has a frame body 110 and a mesh-like inner bone 120 inside the frame body 110. The frame body 110 is a pair of sides connecting the first frame bone 111 continuous with the ear 130, the second frame bone 112 facing the first frame bone 111, and the first frame bone 111 and the second frame bone 112. It includes part frame bones 113 and 114.

The internal bone 120 is an oblique bone that intersects both the first direction from the first frame bone 111 to the second frame bone 112 and the second direction from one side frame bone 113 to the other side frame bone 114. 123 is provided. The diagonal bone 123 is a diagonal bone 123A that approaches the second frame bone 112 toward one side frame bone 113 side and an oblique bone 111 that approaches the first frame bone 111 toward the other side frame bone 114 side. It can be classified as 123B. Further, the inner bone 120 of the illustrated example further includes a vertical bone 121 extending in the first direction and a lateral bone 122 extending in the second direction.

The current collector 100 is, for example, a punched lattice body of a lead or lead alloy stretched sheet, and the stretching direction is the direction indicated by the arrow MD in FIG. The stretching direction MD is a direction perpendicular to the first direction and a direction parallel to the second direction. The cross section C perpendicular to the second direction of the oblique bone is, for example, a cross section taken along line II-II in FIG. The metal structure of the stretched sheet tends to form a layered or fibrous structure extending in the stretching direction. Therefore, a striped pattern of metal fibrous structure can be seen in the cross section C.

FIG. 2 is a photograph of a cross section C perpendicular to the second direction of the oblique bone. In FIG. 2, the cross section C has a substantially octagonal shape, and a striped pattern of metal fibrous structure can be seen. The outer peripheral region of the cross section C is composed of a first portion 210 in which the fibrous structure extends along the contour of the cross section C, and a second portion 220 other than the first portion 210. The second portion 220 is included in the region X surrounded by the white line in FIG. The percentage of the length of the portion corresponding to the second portion in the total length of the contour of the cross section C is r1%. In the outermost surface layer of the second portion 220 of FIG. 2, there is a region where a striped pattern of fibrous tissue having a thickness of less than about 55 μm is observed, and such a thin portion constitutes the first portion 210. do not.

FIG. 3 is a conceptual diagram of a cross section C. In the first portion 210, the fringes of the fibrous structure (tangent line S2) have an angle θ1 less than 45 ° with the contour of the cross section C (line S1). On the other hand, in the second portion 220, the fringes of the fibrous structure cannot be confirmed, or the fringes (tangent line S2) have an angle θ2 that exceeds 45 ° with the contour (line S1) of the cross section C.

The ratio (Σs / S) of the integrated value Σs of the projected area s of the oblique bone 123 in the second direction to the projected area S of the side frame bone 113 or 114 in the second direction is r2. R1 defined by the product of r1 and r2 is set to 110% or less. It should be noted that FIG. 1 shows on the projection planes corresponding to the projected areas S of the side frame bones 113 and 114 in the second direction and the projected areas sa and sb of the representative oblique bones 123A and 123B in the second direction, respectively. Indicates a line segment. The projected area S of the side frame bones 113 and 114 in the second direction does not include the overlapping portion of the projected areas of the first frame bone 111 and the second frame bone 112 in the second direction.

FIG. 4 is a conceptual diagram of a cross section C showing the progress of corrosion of the oblique bone. The portion where the shallow corrosive layer is formed is the first portion 210 in which the fibrous structure extends along the contour of the cross section C, and it is difficult for the corrosive layer to be formed deeply even if the corrosion progresses. On the other hand, peeling tends to occur near the interface between the current collector and the electrode material. Therefore, it is considered that the stress that the current collector tries to deform is easily relaxed. On the other hand, the portion where the wedge-shaped deep corrosive layer is formed is the second portion 220. When a deep corrosive layer is formed, non-uniform deformation of the current collector is likely to occur, the current collector is stretched, and the electrode material is likely to fall off.

A conceptual diagram of a cross section G1 perpendicular to the extension direction of the lateral bone (that is, the second direction) is shown in FIG. In the cross section G1, almost no striped pattern of the metallic fibrous structure is seen, and a cross section perpendicular to the fiber length of the fibrous structure is seen. The outer peripheral region of the cross section G1 is composed of a fibrous structure whose entire circumference extends in the second direction.

Further, FIG. 6 shows a conceptual diagram of a cross section G2 perpendicular to the extension direction (that is, the first direction) of the vertical bone. A striped pattern of metallic fibrous structure is seen in the cross section G2, and the outer peripheral region of the cross section G2 has a considerable proportion of the second portion.

Next, the electrode plate according to one aspect of the present invention includes the lead-acid battery current collector and an electrode material. The electrode material is held in the current collector. The electrode material is a part other than the current collector, but when a mat mainly composed of a non-woven fabric is attached to the electrode plate, the mat is not included in the electrode material. However, the thickness of the electrode plate shall be the thickness including the mat. This is because the mat is used integrally with the electrode plate. However, when a mat is attached to the separator, the thickness of the mat is included in the thickness of the separator.

In the electrode plate, the maximum thickness T of the electrode material and the thickness t of the inner bone of the current collector preferably satisfy T−t ≦ 1 mm. As already mentioned, the thickness of the internal bone is usually constant, but if the thickness changes, the average thickness may be used. The maximum thickness of the electrode material may be calculated by measuring the thickness of only the electrode material portion without the current collector at 10 arbitrary points and averaging the thickness.

Here, (Tt) / 2 corresponds to the thickness of the overpaste. Since the current collector has excellent corrosion resistance and the current collector does not easily stretch due to corrosion, it is necessary to cover the current collector with a thick electrode material in order to suppress corrosion (or suppress contact with the electrolyte). There is no. Therefore, for example, even in a situation where the current collector is exposed from the electrode material and the current collector is about to come into direct contact with the electrolytic solution, deterioration of the current collector due to corrosion is unlikely to proceed. Therefore, even an electrode plate that satisfies Tt ≦ 1 mm can be used for a long period of time. Tt ≧ 0 mm may be used.

The current collector according to the present invention may be applied to either a positive electrode plate or a negative electrode plate. That is, the electrode plate according to the present invention can be either a positive electrode plate or a negative electrode plate. However, the current collector according to the present invention is particularly suitable as a current collector for a positive electrode plate from the viewpoint of suppressing elongation due to corrosion of the current collector.

(Negative electrode plate)
The negative electrode plate of a lead storage battery is composed of a negative electrode current collector and a negative electrode material.
As the lead or lead alloy used in the current collector, Pb-Ca-based alloys, Pb-Ca-Sn-based alloys, lead having a purity equal to or higher than three nines, and the like are preferably used. These leads or lead alloys may further contain Ba, Ag, Al, Bi, As, Se, Cu and the like as additive elements. The negative electrode current collector may have a plurality of lead alloy layers having different compositions.

The negative electrode material contains a negative electrode active material (lead or lead sulfate) whose capacity is developed by a redox reaction as an essential component, and may contain additives such as an organic shrinkage proofing agent, a carbonaceous material, and barium sulfate. The negative electrode active material in the charged state is spongy lead, but the unchemicald negative electrode plate is usually produced using lead powder.

As the organic shrinkage proofing agent, at least one selected from the group consisting of lignins and synthetic organic shrinkage proofing agents may be used. Examples of lignins include lignin and lignin derivatives. Examples of the lignin derivative include lignin sulfonic acid or a salt thereof (such as an alkali metal salt such as a sodium salt). The synthetic organic shrinkage proofing agent is an organic polymer containing a sulfur element, and generally contains a plurality of aromatic rings in the molecule and also contains a sulfur element as a sulfur-containing group. Among the sulfur-containing groups, a sulfonic acid group or a sulfonyl group in a stable form is preferable. The sulfonic acid group may be present in the acid form or in the salt form such as the Na salt.

As a specific example of the organic shrink-proofing agent, a condensate made of an aldehyde compound (aldehyde or a condensate thereof, for example, formaldehyde) of a compound having a sulfur-containing group and an aromatic ring is preferable. Examples of the aromatic ring include a benzene ring and a naphthalene ring. When the compound having an aromatic ring has a plurality of aromatic rings, the plurality of aromatic rings may be directly bonded or linked by a linking group (for example, an alkylene group, a sulfone group, etc.). Examples of such a structure include biphenyl, bisphenyl alkane, bisphenyl sulfone and the like. Examples of the compound having an aromatic ring include the above-mentioned compound having an aromatic ring and a hydroxy group and / or an amino group. The hydroxy group or amino group may be directly bonded to the aromatic ring, or may be bonded as an alkyl chain having a hydroxy group or amino group. As the compound having an aromatic ring, a bisphenol compound, a hydroxybiphenyl compound, a hydroxynaphthalene compound, a phenol compound and the like are preferable. The compound having an aromatic ring may further have a substituent. The organic shrinkage proofing agent may contain one type of residues of these compounds, or may contain a plurality of types. As the bisphenol compound, bisphenol A, bisphenol S, bisphenol F and the like are preferable.

The sulfur-containing group may be directly bonded to the aromatic ring contained in the compound, or may be bonded to the aromatic ring as an alkyl chain having a sulfur-containing group, for example.

Further, for example, a condensate of the above compound having an aromatic ring and a monocyclic aromatic compound (aminobenzenesulfonic acid, alkylaminobenzenesulfonic acid, phenolsulfonic acid or a substitute thereof, etc.) with an aldehyde compound can be obtained. , May be used as an organic shrinkage proofing agent.

The content of the organic shrink-proofing agent contained in the negative electrode electrode material is, for example, preferably 0.01% by mass or more, more preferably 0.02% by mass or more, still more preferably 0.05% by mass or more. On the other hand, 1.0% by mass or less is preferable, 0.8% by mass or less is more preferable, and 0.5% by mass or less is further preferable. These lower limit values and upper limit values can be arbitrarily combined.

As the carbonaceous material contained in the negative electrode material, carbon black, graphite, hard carbon, soft carbon and the like can be used. Examples of carbon black include acetylene black, furnace black, and lamp black. Furness Black also includes Ketjen Black (trade name). The graphite may be any carbon material containing a graphite-type crystal structure, and may be either artificial graphite or natural graphite.

The content of the carbonaceous material in the negative electrode material is, for example, preferably 0.05% by mass or more, and more preferably 0.2% by mass or more. On the other hand, 4.0% by mass or less is preferable, 3% by mass or less is more preferable, and 2% by mass or less is further preferable. These lower limit values and upper limit values can be arbitrarily combined.

The content of barium sulfate in the negative electrode electrode material is, for example, preferably 0.5% by mass or more, more preferably 1% by mass or more, and further preferably 1.3% by mass or more. On the other hand, 3.0% by mass or less is preferable, 2.5% by mass or less is more preferable, and 2% by mass or less is further preferable. These lower limit values and upper limit values can be arbitrarily combined.

The negative electrode plate can be formed by filling a negative electrode current collector with a negative electrode paste, aging and drying to produce an unchemicald negative electrode plate, and then forming an unchemicald negative electrode plate. The negative electrode paste is prepared by adding water and sulfuric acid to lead powder and various additives and kneading them. In the aging step, it is preferable to ripen the unchemicald negative electrode plate at room temperature or at a higher temperature and high humidity.

The chemical conversion can be carried out by charging the electrode plate group in a state where the electrode plate group including the unchemical negative electrode plate is immersed in the electrolytic solution containing sulfuric acid in the electric tank of the lead storage battery. However, chemical conversion may be performed before assembling the lead-acid battery or the electrode plate group. The chemical formation produces spongy lead.

(Positive plate)
The positive electrode plate of the lead storage battery includes a positive electrode current collector and a positive electrode material.
The positive electrode current collector can be formed by press punching a lead or lead alloy sheet. The sheet is preferably a stretched sheet (also referred to as a rolled plate) that has been stretched. The stretched sheet may be a uniaxially stretched sheet or a biaxially stretched sheet.

As the lead or lead alloy used in the positive electrode current collector, a Pb-Ca-based alloy or a Pb-Ca-Sn-based alloy is preferable from the viewpoint of corrosion resistance and mechanical strength, and lead having a purity higher than that of three nines may be used. The positive electrode current collector may have lead alloy layers having different compositions, and may have a plurality of alloy layers.

The positive electrode material contains a positive electrode active material (lead dioxide or lead sulfate) whose capacity is developed by a redox reaction. The positive electrode material may contain additives, if necessary.

The unchemical positive electrode plate is obtained by filling a positive electrode current collector with a positive electrode paste, aging and drying. After that, an unchemical positive electrode plate is formed. The positive electrode paste is prepared by kneading lead powder, additives, water, sulfuric acid and the like.

(Electrolytic solution)
The electrolytic solution is an aqueous solution containing sulfuric acid, and may be gelled if necessary. The specific gravity of the electrolytic solution at 20 ° C. in the ready-made and fully charged lead-acid battery is, for example, 1.20 to 1.35, preferably 1.25 to 1.32.

(Separator)
A separator is usually arranged between the negative electrode plate and the positive electrode plate. A non-woven fabric, a microporous membrane, or the like is used as the separator. Nonwoven fabric is a mat that is entwined without weaving fibers, and is mainly composed of fibers. For example, 60% by mass or more of the non-woven fabric is made of fibers. As the fiber, glass fiber, polymer fiber, pulp fiber and the like can be used. The non-woven fabric may contain components other than fibers, for example, an acid-resistant inorganic powder, a polymer as a binder, and the like. The microporous membrane is a porous sheet mainly composed of components other than fiber components. For example, a composition containing a pore-forming agent (polymer powder, oil, etc.) is extruded into a sheet and then the pore-forming agent is removed. It is obtained by forming pores. The microporous membrane is preferably composed mainly of a polymer component. As the polymer component, polyolefins such as polyethylene and polypropylene are preferable.

FIG. 7 shows the appearance of an example of the lead storage battery according to the embodiment of the present invention.
The lead-acid battery 1 includes an electric tank 12 that houses the electrode plate group 11 and an electrolytic solution (not shown). The inside of the electric tank 12 is partitioned into a plurality of cell chambers 14 by a partition wall 13. In each cell chamber 14, one electrode plate group 11 is stored. The opening of the battery case 12 is closed by a lid 15 including a negative electrode terminal 16 and a positive electrode terminal 17. The lid 15 is provided with a liquid spout 18 for each cell chamber. At the time of refilling water, the liquid spout 18 is removed and the refilling 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 battery.

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. In the cell chamber 14 located at one end of the battery case 12, the negative electrode shelf portion 6 for connecting the ears 2a of the plurality of negative electrode plates 2 in parallel is connected to the penetrating connection body 8, and the ears 3a of the plurality of positive electrode plates 3 are connected. The positive electrode shelf 5 connected in parallel is connected to the positive electrode column 7. The positive electrode column 7 is connected to the positive electrode terminal 17 outside the lid 15. In the cell chamber 14 located at the other end of the battery case 12, the negative electrode column 9 is connected to the negative electrode shelf 6, and the through connector 8 is connected to the positive electrode shelf 5. The negative electrode column 9 is connected to the negative electrode terminal 16 outside the lid 15. Each through-connecting body 8 passes through a through-hole provided in the partition wall 13 and connects the electrode plates 11 of the adjacent cell chambers 14 in series.

Although FIG. 7 shows an example of a liquid battery (vent type battery), the lead storage battery may be a control valve type battery (VRLA type).

Next, the performance evaluation of the current collector and the lead storage battery will be described.
[Evaluation of test battery]
Perform a veneer overcharge test. Using a predetermined test battery, an overcharge test with a constant current of 1.7 A (current density: 0.0054 A / cm ² ) was performed for 5 days in a water tank at 75 ° C., and then the operation (1 week) of resting for 2 days was performed for 3 days. Repeat for a week. The area of the positive electrode plate when calculating the current density is twice the product of the height and width of the outer method of the frame of the positive electrode current collector.

After the overcharge test for 3 weeks, the test battery was disassembled, and the dimensions of the most bulging part in the first direction (height direction) and the second direction (width direction) of the frame of the positive electrode current collector were measured. , Find the width elongation and height elongation compared to the initial dimensions.

The lead-acid batteries according to the present invention are summarized below.
(1) A current collector for a storage battery, which has a frame body, an ear provided on the frame body, and an inner bone inside the frame body, and the frame body is continuous with the ear. The internal bone comprises a first frame bone, a second frame bone facing the first frame bone, and a pair of side frame bones connecting the first frame bone and the second frame bone. Provided an oblique bone that intersects both the first direction from the first frame bone to the second frame bone and the second direction from one side frame bone to the other side frame bone. In the cross section perpendicular to the second direction of the diagonal bone, a striped pattern of metal fibrous tissue is seen, and the outer peripheral region of the cross section is the first portion where the fibrous tissue extends along the contour of the cross section. The percentage of the length of the portion corresponding to the second portion to the total length of the contour of the cross section, which is composed of the second portion other than the first portion, is r1%, and the side frame bone is said to have the same proportion. The ratio of the integrated value Σs of the projected area s of the diagonal bone in the second direction to the projected area S in the second direction: When Σs / S is r2, the product of r1 and r2: R1 is 110. % Or less.

(2) In the above (1), the current collector for a storage battery in which the ratio r1 is 40% or less.

(3) In the above (1) or (2), the current collector for a storage battery in which the ratio R1 is 40% or less.

(4) In any one of the above (1) to (3), the current collector for a storage battery in which the ratio R2 of the thickness of the inner bone to the thickness of the side frame bone is 78 to 95%.

(5) The lead storage battery current collector according to any one of (1) to (4) above and the electrode material held by the lead storage battery current collector are provided, and the maximum thickness T of the electrode material is provided. And the electrode plate in which the thickness t of the inner bone is Tt ≦ 1 mm.

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

(1) Preparation of Lattice Body A1 A rolled sheet of Pb-Ca-Sn alloy is punched out, and the inner bone is pressed to obtain a lattice body A1 as a current collector.

The specifications of the lattice body A1 are as follows.
<Frame body>
Frame height H: 115mm
Length of lateral frame bone in first direction: 110.5 mm
Frame width W: 137 mm
Frame thickness: 0.95 mm (average value of any 10 locations)
Projected area of the lateral frame bone in the second direction S: 105 mm ²

<Inner bone>
Internal bone thickness: 0.90 mm (average value of any 10 points)
Integrated value of projected area s of diagonal bone in the second direction Σs: 267.0 mm ²
Ratio of the second part r1: 40%
Percentage of diagonal bones in total internal bone length: 35.9%
Ratio of diagonal bone to the total length of diagonal bone and lateral bone: 79.1%

<Others>
Ratio of internal bone thickness to lateral frame bone thickness R2: 94.7%
r2 (Σs / S): 2.54
R1 (r1 (%) x r2): 102%

(2) Preparation of Positive Electrode Plate A positive electrode paste containing lead powder is prepared, the lattice body A1 is filled with the positive electrode paste, and aged and dried to prepare an unchemicald positive electrode plate. The density of the positive electrode material after chemical conversion is adjusted to ^{3.6 g / cm 3.} The maximum thickness T of the positive electrode material and the thickness t of the internal bone satisfy the relationship of Tt ≦ 1 m.

(3) Preparation of negative electrode plate Lead powder, water, dilute sulfuric acid, barium sulfate, carbon black and an organic shrink-proofing agent are mixed to prepare a negative electrode paste. The lattice body A1 is filled with a negative electrode paste and aged and dried to obtain an unchemicald negative electrode plate.

(4) Preparation of test battery (2V, rated 5 hour rate capacity 6Ah) A test battery is composed of one unchemical positive electrode plate and two unchemical negative electrode plates sandwiching the positive electrode plate, and the test battery is formed in an electrolytic solution. The battery A1 is manufactured. The negative electrode plate is housed in a bag-shaped separator. After the chemical conversion, the specific gravity of the electrolytic solution (sulfuric acid aqueous solution) at 20 ° C. is adjusted to 1.28 in each fully charged test battery.

<< Example 2 >>
R1 = 39 in the same manner as in Example 1 except that R1 was changed to 84.2% and r1 = 17.4% and r2 = 2.26 (Σs: 237.4 mm ^2). % Lattice body A2 is produced, and a battery A2 is produced.

<< Example 3 >>
A lattice body A3 having R1 = 21% was produced in the same manner as in Example 1 except that R2 was changed to 79% and r1 = 10.1% and r2 = 2.12. A3 is produced.

<< Comparative Example 1 >>
R1 = in the same manner as in Example 1 except that R2 was changed to 97.9% and r1 = 43.8%, r2 = 2.63 (Σs: 275.9 mm ^2)). A 115% lattice body B1 is produced, and a battery B1 is produced.

[Evaluation results]
The results of the single plate overcharge test are shown in Table 1 and FIG.

From Table 1 and FIG. 8, it can be understood that when R1 exceeds 110%, the width elongation becomes remarkable.

The lead-acid battery lattice body according to the present invention is applicable to control valve type and liquid type lead-acid batteries, and is used for starting power sources for automobiles, motorcycles, etc., and industrial power storage devices for electric vehicles (forklifts, etc.). It can be suitably used as a power source.

1: Lead-acid battery, 2: Negative electrode plate, 3: Positive electrode plate, 4: Separator, 5: Positive electrode shelf, 6: Negative electrode shelf, 7: Positive electrode column, 8: Through connector, 9: Negative electrode column, 11: Pole Plate group, 12: battery case, 13: partition wall, 14: cell chamber, 15: lid, 16: negative electrode terminal, 17: positive electrode terminal, 18: liquid port plug, 100: current collector, 110: frame, 111: 1st frame bone, 112: 2nd frame bone, 113, 114: lateral frame bone, 120: internal bone, 121: vertical bone, 122: lateral bone, 123: diagonal bone, 130: ear, 210: 1st part , 220: Part 2

Claims (5)

It has a frame, ears provided on the frame, and an inner bone inside the frame.
The frame body is a pair of side frames connecting the first frame bone continuous with the ear, the second frame bone facing the first frame bone, and the first frame bone and the second frame bone. Equipped with bones,
The internal bone is an oblique bone that intersects with both the first direction from the first frame bone to the second frame bone and the second direction from one side frame bone to the other side frame bone. Equipped with
In the cross section perpendicular to the second direction of the oblique bone, a striped pattern of metal fibrous tissue is seen, and the outer peripheral region of the cross section is the first portion where the fibrous tissue extends along the contour of the cross section. , A second part other than the first part,
The percentage of the length of the portion corresponding to the second portion in the total length of the contour of the cross section is r1%.
When the ratio of the integrated value Σs of the projected area s of the diagonal bone in the second direction to the projected area S of the side frame bone in the second direction: Σs / S is r2.
Product of r1 and r2: A current collector for a storage battery in which R1 is 110% or less. The current collector for a storage battery according to claim 1, wherein the ratio r1 is 40% or less. The current collector for a storage battery according to claim 1 or 2, wherein the ratio R1 is 40% or less. The current collector for a storage battery according to any one of claims 1 to 3, wherein the ratio R2 of the thickness of the inner bone to the thickness of the side frame bone is 78 to 95%. The lead-acid battery current collector according to any one of claims 1 to 4 and an electrode material held by the lead-acid battery current collector are provided.
An electrode plate in which the maximum thickness T of the electrode material and the thickness t of the internal bone are Tt ≦ 1 mm.

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