JP2007066786A - Expanded lattice body for lead-acid battery, lead-acid battery, and manufacturing method of expanded lattice body for lead-acid battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem where advances of local corrosion in expanded mesh intersection parts are seen when an expanded lattice body is used for the positive electrode side, and the corrosion advances in the intersection parts in the upper part of the lattice body as compared with those in the lower part, whereby a battery service life is reduced. <P>SOLUTION: This lattice body for a lead-acid battery has a part having a distance d (d>0) between a first virtual line passing an apex corresponding to the mesh intersection part of one-side rhombic lattice mesh relatively adjacent to a frame bone and parallel to the expanded mesh expansion direction and a second virtual line passing an apex corresponding to the mesh intersection part of the other-side rhombic lattice mesh and parallel to the expanded mesh expansion direction in rhombic lattice meshes adjacent to each other through a mesh intersection part and along the expanded mesh expansion direction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an expanded lattice body used for a lead storage battery, a method for producing the same, and a lead storage battery using the expanded lattice body.

  As a general method of manufacturing a lead-acid battery grid, there are a casting method and an expanding method, but at present, an expanding method with high productivity is mainly used. This expand method uses an expanded mold in which a plurality of reciprocating die blades are arranged, and simultaneously forms slits in a metal (lead or lead alloy) sheet in a zigzag pattern, while at the same time expanding the slitted portion on the cutting edge surface of the die blade. A method of forming an expanded mesh portion having an approximately rhombus shape is used.

  When forming an expanded mesh, stress tends to concentrate at the mesh intersection. As a result, there is a problem that cracks enter the intersections and the lattices corrode starting from such cracks.

  In particular, when the mesh intersection is broken due to the progress of corrosion, the current collection performance of the grid body is rapidly deteriorated. In particular, in applications that are used for rapid discharge, such as a lead-acid storage battery for starting, the discharge voltage is drastically reduced, resulting in a short life. Such a sudden decrease in the lifetime occurs suddenly without any sign of battery deterioration for the user, and is extremely inconvenient for the battery user.

In order to suppress a sudden decrease in battery life caused by such corrosion at the mesh intersections, for example, Patent Document 1 discloses that the cross-sectional area at the mesh intersections is successively reduced from the upper part to the lower part of the grid. It is shown. With such a configuration, the disconnection due to corrosion at the intersections proceeds from the lower part of the grid body that does not significantly affect the discharge voltage characteristics, so that the voltage characteristics can be gradually lowered. As a result, the user can be notified of battery deterioration.
JP-A-6-333572

  The configuration disclosed in Patent Document 1 suppresses rapid discharge voltage characteristic degradation by gradually causing lattice corrosion to proceed from the lower part, and does not suppress corrosion at the network intersection. Therefore, even if a sudden decrease in the lifetime could be avoided, the lifetime was not significantly improved.

  The present invention suppresses corrosion occurring at the mesh intersections of the expanded lattice, and has an excellent corrosion resistance, and an expanded lattice for lead-acid batteries and a method for producing the expanded lattice, and further uses the expanded lattice to provide excellent lifetime characteristics. The lead acid battery which it has is provided.

  In order to solve the above-mentioned problem, the invention according to claim 1 of the present invention is an expanded grid for a lead storage battery in which an expanded mesh portion is connected to a frame bone having a current collecting ear portion, and the mesh intersection portion In the rhomboid lattice adjacent to each other along the expanded mesh development direction, the first rhomboid mesh closer to the frame bone passes through the apex corresponding to this mesh intersection and is parallel to the expand mesh development direction. A distance d (d> 0) between one virtual line and a second virtual line passing through the vertex corresponding to the mesh intersection point of the other rhombus lattice and parallel to the expanded mesh development direction The expanded lattice body for lead acid batteries which has the part which has was shown.

  According to a second aspect of the present invention, in the expanded lattice body for a lead storage battery according to the first aspect, the distance d between the first imaginary line and the second imaginary line is d ≦ 0.7 mm. It is what.

  Furthermore, the invention according to claim 3 of the present invention is such that, in the expanded lattice body for a lead storage battery according to claim 1 or 2, the distance d described above is made smaller as the distance from the frame bone is increased.

  Moreover, the invention which concerns on Claim 4 of this invention shows the lead acid battery provided with the expanded lattice body for lead acid batteries of Claim 1, 2, and 3.

  In the invention according to claim 5 of the present invention, a strip-shaped metal sheet is intermittently fed into an expanding mold having a plurality of reciprocating die blades, and slits are formed in a staggered pattern on the metal sheet. It is a manufacturing method of an expanded lattice body for a lead storage battery that expands to form an expanded mesh, and the tip position of the tip of the die blade is set at a position separated from the longitudinal center line of the slit formed by the die blade. It is a feature.

  And the invention which concerns on Claim 6 of this invention is the manufacturing method of the expanded grid | lattice body for lead acid batteries of Claim 5, and makes the angle which this metal sheet | seat makes | forms the angle | corner surface of this metal sheet and the cutting edge surface by the side of the metal sheet of die | dye blade, When the angle formed between the cutting edge surface of the die blade on the metal sheet input side and the metal sheet is θin, θout ≠ θin.

  In the expanded grid for lead-acid batteries having the configuration according to claims 1 to 3, unlike the conventional expanded grid, the center of the mesh intersection and the tip of the die blade do not coincide with each other. Can prevent cracking and corrosion. In addition, since a distance is generated between the two vertices of the rhombic lattice that is continuous in the vertical direction, the cross-sectional area of the mesh intersection can be increased by this distance. This increase in cross-sectional area has the effect of suppressing Joule heat generation at the intersection where the current concentrates, and reducing the corrosion rate here.

  The lead storage battery of Claim 4 can obtain the lead storage battery excellent in the high temperature life by having the expanded lattice body for lead storage batteries of Claims 1-3.

  The method for producing an expanded lattice body for a lead storage battery according to claims 5 and 6 shows the method for producing an expanded lattice body according to claims 1 to 3, and in the expansion process, when forming the slit with a die blade, By adopting a configuration in which the central position of the length does not coincide with the tip of the die blade, an expanded lattice body for a lead storage battery having excellent corrosion resistance can be obtained.

  Embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a view showing an expanded lattice body for a lead storage battery according to an embodiment of the present invention, and FIG. 2 is a view showing an essential part thereof. The expanded lattice body 101 of the present invention is the same as the conventional expanded lattice body for a lead storage battery in that an expanded mesh portion 104 is provided on a frame bone 103 having current collecting ear portions 102.

  The expanded lattice body 101 of the present invention has two rhombus lattices 105a and 105b that are adjacent to each other along the expanding direction through a certain mesh intersection 106, and the rhombus lattice 105a closer to the frame bone 103. The first imaginary line L passing through the vertex 107a corresponding to the mesh intersection 106 and parallel to the expanding direction and the vertex 107b corresponding to the mesh intersection 106 of the other rhombus lattice 105b are expanded. A distance d (d> 0) is provided between the second virtual line M parallel to the direction.

  That is, in the rhombic lattices 105a and 105b adjacent to each other in the expanding direction, a distance d is provided between the vertex 107a and the vertex 107b corresponding to the mesh intersection point 106 shared with each other, and the vertex 107a and the vertex 107b do not coincide with each other. Position.

  Thereby, since the cross-sectional area S of the mesh intersection portion 106 shown in FIG. 3 can be further secured by the distance d between the vertices, the Joule heat generation at the mesh intersection portion 106 is suppressed, and corrosion at this portion is suppressed. be able to.

  Further, by not matching the vertices 107a and 107b, it is possible to suppress the concentration of stress at the mesh intersection point 106, thereby suppressing the occurrence of cracks and the corrosion of the mesh intersection point 106 starting from this crack. .

  The distance d is preferably within this range since the effects of the present invention have been confirmed within a range of 0.7 mm or less according to the examples described later.

  Also, in order to balance the current collection efficiency and mass of the expanded mesh, when forming slits 402 in a zigzag pattern in a lead or lead alloy sheet 401 as shown in FIG. It has been conventionally performed to decrease the distance from the position close to the plain portion 403 forming the frame bone.

  In such a case, as the cut width x becomes larger, the frequency of occurrence of cracks at the mesh intersection 106 increases, so that the distance d is larger at the portion where the cut width x is larger and the portion where the cut width x is smaller. Thus, by setting the distance d to be smaller, it is possible to obtain an expanded lattice body that is lighter and has excellent current collection efficiency and corrosion resistance.

In FIG. 2, such a configuration corresponds to d ₀ ≦ d ≦ d ₁ ≦ d ₂ (where d ₀ <d ₂ ) as the distance d is separated from the frame bone 103.

  By using the expanded grid for a lead storage battery of the present invention as described above, a long-life lead storage battery can be obtained by improving the corrosion resistance of the grid. In particular, in lead acid batteries for start-up that are overcharged at high temperature and lead acid batteries for backup, corrosion due to oxidation becomes a problem. Therefore, the expanded grid for lead acid batteries of the present invention is used for the positive electrode of these lead acid batteries. It is valid.

  Next, the manufacturing method of the expanded lattice body for lead acid batteries of this invention is demonstrated using drawing. In the present invention, as shown in FIG. 5, a strip-shaped metal (made of lead or lead alloy) is formed on an expanding mold 502 having a plurality of die blades 501a, 501b, 501c, 501d, 501e, 501f, and 501g that reciprocate. The sheet 401 is intermittently fed, slits are formed in a staggered pattern on the sheet 401, and the expanded mesh portion 104 is formed by expanding the slit forming portion, so that there is no replacement for the conventional expanded lattice.

  In the present invention, the cutting edge tip position (corresponding to the first imaginary line L in FIGS. 2, 3, and 6) of the die blade (the die blade 501f in the example of FIG. 6) is the slit formed by the die blade 501f. It is set at a position separated from the longitudinal center line N. That is, as shown in FIG. 6, when the slit length is z, the slit length direction center line N is located at a position (z / 2) from both ends of the slit, and the line N and the cutting edge of the die blade 501f When the distance from the tip position (first imaginary line L) is y, a value of y> 0 is set. And by changing this distance y, it becomes possible to set the distance d shown in FIG. 2, and the expanded lattice body for lead acid batteries of this invention can be obtained.

  As a method for setting the distance y, an angle formed between the sheet 401 of the die 401 501f on the sheet 401 and the sheet 401 and the sheet 401 is θout, and the blade 401 on the sheet 401 input side of the die 501f. When the angle between the sheet 602 and the sheet 401 is θin, θout ≠ θin may be satisfied. In the example of FIG. 6, an example in which θout> θin is shown. Although the shape of the die blade 501f has been described with reference to FIG. 6, the die blade 501f is applied to the die blade except the die blade 501a having a trapezoidal shape, which is located at the end of the input side having a trapezoidal shape and forms the bottom of the expanded lattice. can do.

  Depending on the location of the mesh intersection point 106, there is a part where the crack occurrence frequency is negligibly low. Therefore, it is not necessary to secure the distance d in such a part, and the distance d is high in the part where the crack occurrence frequency is high. Should be secured.

  As the sheet 401, a Pb alloy containing an alloy component such as Ca, Sn, Ba, Bi, and Al, which has been conventionally used for a lead storage battery expanded lattice, can be used.

  The expanded mesh portion 104 was formed using the sheet 401 using the expanding mold 502 shown in FIG. As in the conventional art, each of the blade surfaces of the die blades 501a, 501b, 501c, 501d, 501e, 501f, and 501g is provided with a stepped step (not shown), and seven die blades are 80 mm in height. It is assumed that Note that this step corresponds to the cutting width at the time of expanding, that is, the lattice bone width, and can be changed as necessary.

  As described above, the die blade 501a of the first blade on the input material side is the outermost part of the expanded mesh portion, and usually has a trapezoidal shape to correspond to the bottom portion of the lattice body. Moreover, all the sheets used the 0.9-mm-thick rolled lead alloy sheet | seat which has the alloy composition of Pb-0.06 mass% Ca-1.6 mass% Sn.

  In the present embodiment, by changing the distance y shown in FIG. 6 variously in the cutting edge shapes of the die blades 501b, 501c, 501d, 501e, 501f, and 501g after the second blade from the input material side, An expanded grid for a lead storage battery of a comparative example was prepared.

(1) Expanded lattice body 1 according to the present invention
In the expanded lattice body 1 according to the present invention, the distance y shown in FIG. 6 is all 0.5 mm excluding the die blade of the first blade from the input material side. The cutting width was the same as 1.0 mm for all the die blades. As a result, when the distances d ₀ , d, d ₁ , d ₂ , and d ₃ shown in FIG. 1 were measured in the expanded lattice 1, these values were all 0.5 mm.

(2) Expanded lattice body 2 according to the present invention
In the expanded lattice body 1 according to the present invention, the distance y shown in FIG. 6 is all 0.5 mm excluding the die blade of the first blade from the input material side. However, the cutting width is 1.3 mm from the 7th blade (first blade from the unloading side) from the input side, and the die blades are sequentially reduced by 0.1 from the unloading side to the input side. It is. As a result, when the distances d ₀ , d, d ₁ , d ₂ , and d ₃ shown in FIG. 1 were measured in the expanded lattice 2, these values were all 0.5 mm.

(3) Expanded lattice 3 according to the present invention
In the expanded lattice body 3 according to the present invention, the distance y shown in FIG. 6 is 0.2 mm except for the die blade of the first blade from the input material side. All the cutting widths were the same at 1.0 mm. As a result, when the distances d ₀ , d, d ₁ , d ₂ , and d ₃ shown in FIG. 1 were measured in the expanded lattice 3, these values were all 0.2 mm.

(4) Expanded lattice 4 according to the present invention
In the expanded lattice body 4 according to the present invention, the distance y shown in FIG. 6 is 0.7 mm except for the die blade of the first blade from the input material side. All the cutting widths were the same at 1.0 mm. As a result, when the distances d ₀ , d, d ₁ , d ₂ , and d ₃ shown in FIG. 1 were measured in the expanded lattice 4, all of these values were 0.7 mm.

(5) Expanded lattice body 5 according to the invention example
In the expanded lattice body 5 according to the present invention, the distance y shown in FIG. 6 is 0.7 mm except for the die blade of the first blade from the input side. However, the cutting width is 1.3 mm from the 7th blade (first blade from the unloading side) from the input side, and the die blades are sequentially reduced by 0.1 from the unloading side to the input side. It is. When the distances d ₀ , d, d ₁ , d ₂ , and d ₃ shown in FIG. 1 were measured in the expanded lattice 5, all of these values were 0.7 mm.

(6) Expanded lattice body 6 according to a comparative example
The expanded lattice 6 according to the comparative example has all the distances y shown in FIG. The cutting width was the same as 1.0 mm for all the die blades. As a result, when the distances d ₀ , d, d ₁ , d ₂ , and d ₃ shown in FIG. 1 were measured in the expanded lattice body 6, these values were all 0 mm.

(7) Expanded lattice 7 according to a comparative example
The expanded lattice body 7 according to the comparative example has the distance y shown in FIG. However, the cutting width is 1.3 mm from the 7th blade (first blade from the unloading side) from the input side, and the die blades are sequentially reduced by 0.1 from the unloading side to the input side. It is. As a result, when the distances d ₀ , d, d ₁ , d ₂ , and d ₃ shown in FIG. 1 were measured in the expanded lattice 7, these values were all 0 mm. Note that the distance y and the distance d coincided with each other in the present invention example and the comparative example.

  In each of the above expanded lattices, the cross-sectional area S of the mesh intersection 106 was measured. Note that the cross-sectional area at the mesh intersection 106 closest to the frame bone 103 is Sa, excluding the intersection with the frame bone 103, and thereafter, at each mesh intersection 106 as the distance from the frame 103 increases, The areas were Sb, Sc, Sd, and Se. Table 1 shows the measurement results of these cross-sectional areas. In addition, each cross-sectional area was shown by the percentage with respect to cross-sectional area Sa in the expanded lattice body 6 of a comparative example.

  From the results shown in Table 1, the expanded lattice body according to the example of the present invention can secure a larger cross-sectional area at the mesh intersection by having the distance d. In the expanded grid 7 according to the comparative example, the cross-sectional area at the mesh intersection near the frame bone can be increased by increasing the cut width, but there is a limitation on the sheet width. Since the width must be reduced, the cross-sectional area in this part must be reduced. If the sheet width is increased, it is not necessary to reduce the cutting width at the portion separated from the frame bone. However, in this case, the lattice mass increases, which is not preferable in terms of battery weight reduction.

  In the present invention, the setting of the distance d can be controlled by the distance y which is the amount of eccentricity of the tip of the die blade. In the expanded lattice body 3 according to the present invention in which the distance d is 0.7 mm or 0.5 mm to 0.2 mm, the cross-sectional area of the mesh intersection portion decreases, but the effect of increasing the cross-section area of the mesh intersection portion can be obtained. it can. By increasing the distance d, the cross-sectional area of the mesh intersection can be increased. However, it is difficult to secure the expanded width of the expanded mesh, so it should be at least 1.0 mm at the maximum.

  Next, a positive electrode active material paste for a lead storage battery is applied to each of the expanded grids, and a positive electrode plate obtained by aging and drying, and a negative electrode active material paste for a lead storage battery is applied to the expanded grid 6. The negative electrode plate obtained by aging and drying was stored in a bag-like microporous polyethylene separator, and these were combined to produce a 12V28Ah lead acid battery.

  Table 2 shows combinations of positive and negative electrode grids in these batteries.

  Each battery shown in Table 2 was subjected to a low-temperature high-rate discharge characteristic and a light load life test under the following conditions.

(1) Low-temperature high-rate discharge voltage characteristics Test temperature: -15 ° C (gas phase)
Discharge current: 150A
Discharge time: 5 seconds The final discharge voltage V ₅ in the above discharge is measured.

(2) Light load life test Test temperature: 75 ° C (gas phase)
Charging / discharging cycle: 25A x 4 minutes after discharge, 10 minutes at 14.8V constant voltage (maximum current 25A)
Inter-charging performance confirmation: 30 second voltage with 332A discharge every 480 charge / discharge cycles above
Measure. Life test ends when the voltage at 30 seconds drops below 7.2V
By extrapolating from the relationship between the voltage at 30 seconds and the number of cycles,
The number of cycles for which the voltage at the 30th second is 7.2 V is obtained and this is calculated as the number of life cycles
And

  Table 3 shows the low temperature high rate discharge voltage characteristics and the life cycle number in the light load life test. However, the life cycle number is shown as a percentage of the life cycle number of the battery 6.

  From the results shown in Table 6, it can be seen that the batteries 1 to 5 according to the present invention are superior in both low temperature and high rate discharge voltage characteristics and life characteristics as compared with the batteries 6 and 7 of the comparative example.

  As a result of disassembling and investigating the end-of-life test of each battery, in the battery 6 of the comparative example, disconnection due to corrosion occurred at the upper mesh intersection near the frame of the positive grid. Although the battery 7 of the comparative example had a longer life than the battery 6 of the comparative example, as with the battery 5 of the comparative example, corrosion proceeded at the mesh intersections above the lattice.

  On the other hand, the batteries 1 to 5 of the present invention were found to have a significantly longer life than the batteries of the comparative examples by securing the distance d. In particular, as the distance d is increased, the lifetime is further extended. However, the battery 1 with d of 0.5 mm and the battery 2 with d of 0.7 mm do not have a significant difference in life, and are preferably set to 0.7 mm or less.

  In particular, the battery 2 and the battery 5 in which the configuration in which the cutting width close to the frame bone is increased and the cutting width is sequentially decreased as the distance from the frame bone is applied to the present invention are the comparisons having the same cutting width. Compared to the battery 7 of the example, it has extremely excellent life characteristics.

  This is thought to be because cracks during the expanding process that are likely to occur when the cutting width is increased set the distance d to be suppressed by stress concentration relaxation, and the decrease in the current collection rate is suppressed. Moreover, coupled with the fact that a large cross-sectional area at the mesh intersection is secured and cracking is suppressed, the amount of Joule heat generation at the mesh intersection is suppressed, and corrosion at this portion is significantly suppressed. It is done.

  As described above, according to the configuration of the present invention, it is possible to provide a lead-acid battery expanded grid having excellent discharge voltage characteristics and life characteristics, a lead-acid battery, and a method for manufacturing the grid. it can. In this example, the example in which the expanded lattice body of the present invention was applied to the positive electrode side was described. However, even when applied to the negative electrode side, excellent discharge voltage characteristics can be obtained, and the mesh during the high-temperature life test can be obtained. Since it becomes possible to suppress heat generation at the intersection, it is possible to suppress a decrease in life at high temperatures.

  Since the present invention has a remarkable effect in improving discharge voltage characteristics and high temperature life characteristics, it is extremely suitable for lead storage batteries for various uses such as start-up lead storage batteries and backup lead storage batteries.

The figure which shows the expanded lattice body for lead acid batteries of this invention The figure which shows the principal part of an expanded lattice body The figure which shows the mesh | network intersection part of an expanded lattice body Diagram showing cutting width x Diagram showing the expansion process Enlarged view showing the expanding process

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Expanded grid body 102 Current collection ear part 103 Frame bone 104 Expanded mesh part 105a, 105b Diamond mesh 106 Mesh intersection part 107a, 107b Vertex 401 Sheet 402 Slit 403 Uncoated part 501a, 501b, 501c, 501d, 501f, 501g Die blade 502 Expanded type 601 (Drawing material side) Cutting edge surface 602 (Input material side) Cutting edge surface L First virtual line M Second virtual line N Center line in the longitudinal direction of the slit

Claims (6)

An expanded grid for a lead-acid battery in which an expanded mesh is connected to a frame bone having a current collecting ear,
In the rhomboid lattice that is adjacent through the mesh intersection and along the expanded mesh development direction,
A first imaginary line that passes through the apex corresponding to the mesh intersection portion of one of the rhombic lattices closer to the frame bone and is parallel to the expanded mesh development direction;
A portion having a distance d (d> 0) between the second virtual line passing through the vertex corresponding to the mesh intersection of the other rhombus lattice and parallel to the expanded mesh development direction Expanded grid for lead-acid batteries. 2. The expanded grid for lead-acid batteries according to claim 1, wherein the distance d is d ≦ 0.7 mm. The expanded lattice body for a lead storage battery according to claim 1 or 2, wherein the distance d is decreased as the distance d is separated from the frame bone. The lead acid battery provided with the expanded lattice body for lead acid batteries of Claim 1, 2, and 3. A lead-acid battery in which a strip-shaped metal sheet is intermittently fed into an expanded mold having a plurality of reciprocating die blades, and slits are formed in a staggered pattern in the metal sheet, and the slit forming portion is expanded to form an expanded network. A method for producing an expanded lattice for
A manufacturing method of an expanded lattice body for a lead storage battery, wherein a tip end position of the die blade is set at a position separated from a longitudinal center line of a slit formed by the die blade. When the angle formed between the cutting edge surface of the die blade on the metal sheet feeding side and the metal sheet is θout, and the angle formed between the cutting edge surface of the die blade on the metal sheet input side and the metal sheet is θin Furthermore, it is set as (theta) out ≠ (theta) in, The manufacturing method of the expanded lattice body for lead acid batteries of Claim 5 characterized by the above-mentioned.

Images