JP2004311283A - Positive electrode lattice of lead-acid battery, and lead-acid battery using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrode plate lattice excellent in corrosion resistance and to provide a lead-acid battery having an excellent life characteristic by solving problems of lattice deformation generated in corrosion of a positive electrode and life degradation due to active material dropout. <P>SOLUTION: This positive electrode lattice body 100 for this lead acid battery is manufactured by an expansion method. A tilting part decreasing height (h) as it approaches an end of an expansion mesh from a current collecting ear part is formed from the current collecting ear part 102 of an upper frame bone 101 to the end of the expansion mesh 103 in an electrode plate width center line direction; and when it is assumed that an angle formed by the extension line of the upper end of the tilting part and the extension line of the lower end of the upper frame bone, and an angle formed by a lattice bone tilting upward from an arbitrary intersecting point of the lattice bones and a lattice bone tilting downward therefrom in a unit block are θ<SB>1</SB>and θ<SB>2</SB>, respectively, θ<SB>2</SB>is set to 60°-70°, and θ<SB>1</SB>is set below 2°. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００３１】
これらの電池を４０℃雰囲気中で１４．８Ｖの定電圧で４週間連続充電し、充電終了後に電池を分解して、図３に示したように、正極格子３００の上枠骨３０１の上方向への枠骨変形量（ｄ）を測定した。そしてそれぞれの電池について求めた枠骨変形量（ｄ）の比較例の電池３の枠骨変形量（ｄ３）に対する百分率を骨変形量比（ｄ´）として表１に示した。
【００３２】
表１に示した結果から、θ１が２°〜７°、θ２が６０°〜７５°の範囲内で枠骨変形量比および極板湾曲量比変形量比を同時に極めて低く抑制できることがわかる。
【００３３】
▲２▼実施例２
次に実施例１の表１に示した電池８および電池１８に関して鉛合金シート中のＳｎ濃度と、袋状セパレータに収納する極板の極性を変化させた電池を作成した。これらの電池を表２に示す。
【００３４】
【表２】

【００３５】
これら表２に示した電池について充電と放電とを繰返して行う寿命サイクル試験を行った。試験条件は充電を４０℃雰囲気中で１４．８Ｖの定電圧充電を１週間、放電を２５℃雰囲気中で３００Ａで５秒間の定電流放電とした。これらの充電と放電を繰返して行い、放電５秒目の電圧が７．２Ｖまで低下した時点を寿命サイクル数とした。これらの寿命試験の結果を図４に示す。
【００３６】
図４に示した結果から、正極格子に用いたＰｂ−Ｃａ−Ｓｎ合金中のＳｎ濃度が１．２０質量％以上の領域では比較例の電池は急激に寿命低下している。一方、本発明例の電池ではＳｎが１．２０質量％以上であっても良好な寿命特性を示す。中でも負極板を袋状セパレータに収納した本発明例の電池では極めて優れた寿命特性を示した。
【００３７】
比較例の電池でＳｎ濃度を１．２０質量％以上としたものは正極格子の上枠骨の変形が一箇所に集中し、その点で上枠骨が折り曲がった状態となっていた。一方、本発明例ではこのようなＳｎ濃度であっても上枠骨の変形は一箇所に集中せず、変形が分散していた。また、Ｓｎ濃度を１．２０質量％未満に低下させていくにしたがい、上枠骨が一箇所で集中的に折れ曲がる変形から上枠骨全体が変形する状態に変化した。また、Ｓｎ濃度低下にしたがい、寿命サイクル数自体も低下した。したがって、本発明のよればＳｎ濃度が１．２０質量％以上の領域においても極めて良好な寿命特性を得ることができる。
【００３８】
また、特に本発明では正極格子の変形抑制により、脱落活物質量も抑制できるので、従来のような正極板を袋状セパレータに収納する必要がない。したがって、正極板を袋状セパレータに収納した時の問題点、すなわち、袋状セパレータの底部の破損による正極−負極間の短絡という問題を回避できる。
【００３９】
【発明の効果】
以上、説明してきたように本発明の構成によれば、腐食時に発生する格子変形と活物質脱落による電池寿命の低下という課題を解決し、長寿命な鉛蓄電池を提供できることから、工業上、極めて有用である。
【図面の簡単な説明】
【図１】本発明による正極格子体を示す図
【図２】エキスパンド網目を示す図
【図３】上枠骨の変形量測定位置を示す図
【図４】寿命試験結果を示す図
【図５】従来のエキスパンド格子体を示す図
【符号の説明】
１００ 正極格子体
１０１ 上枠骨
１０２ 集電耳部
１０３ エキスパンド網目
１０４ 下枠骨
１０５ 傾斜部
１０６ 格子骨
１０６ａ 上方に傾斜した格子骨
１０６ｂ 下方に傾斜した格子骨
１０７ 交点部
２０１ エキスパンド網目
２０２ 切断線
３００ 正極格子
３０１ 上枠骨
５００ エキスパンド格子体
５０１ 上枠骨
５０２ エキスパンド網目
５０３ 下枠骨
５０４ 上枠骨
５０５ 集電耳部
５０６ 格子骨
Ｌ （エキスパンド網目１０３の）中心線
Ｍ （傾斜部１０５の上端の）延長線
Ｎ （上枠骨１０１の下端の）延長線[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a lead storage battery, particularly to a positive electrode grid.
[0002]
[Prior art]
The electrode plate of the lead storage battery has a configuration in which a grid of lead or a lead alloy is filled with an active material. As the lattice body, an expanded lattice body in which slits are formed in a zigzag pattern on a cast lattice body or a rolled lead alloy sheet obtained by solidifying molten lead in a mold and the slits are developed. Expanded lattices are widely used because they can reduce the thickness of the lattice and are excellent in productivity.
[0003]
As shown in FIG. 5, the expanded lattice body 500 has a lower frame bone 503 and an upper frame bone 504 formed integrally with the expanded mesh 502, and the upper frame bone 504 is provided with a current collecting ear 505. Unlike the cast grid, such an expanded grid 501 does not have frame bones on both left and right sides, and further has a low degree of freedom in the shape of a bone in the grid. However, the voltage drop due to the grid body is larger, which is one of the causes of lowering the discharge voltage of the battery.
[0004]
Further, when the expanded lattice body 500 is used as a positive electrode, the expanded lattice body 500 is subjected to oxidative corrosion and extends in the extending direction of two sides having no frame bone, that is, in the direction of arrow A in FIG. Then, there is a problem that the expanded expanded grid body 500 is short-circuited to the negative electrode, and the capacity of the battery is rapidly reduced.
[0005]
It is conventionally known that it is effective to make the current collecting part of the upper frame bone, particularly the upper frame bone thicker or larger, in order to suppress the voltage drop due to these lattice bodies and suppress the elongation due to corrosion. (For example, see Patent Document 1).
[0006]
In addition, there is a method in which a reinforcing portion is provided on a current collecting ear and a bending point position of an upper frame bone generated when the lattice body is extended is defined (for example, see Patent Document 2). In Patent Document 2, when the lattice body is elongated, the deformation of the upper frame bone is preferentially generated at the bending point, and the position of the bending point is provided below the negative electrode shelf, so that even if the upper frame bone is deformed, the negative The structure does not cause a contact short circuit with an extreme.
[0007]
On the other hand, various shapes of the expanded mesh have been studied.
Increasing the developed dimension among them increases the height T after the expansion as the angle θ between the lattice bones 506 increases, so that the weight of the positive electrode lattice body 500 can be relatively reduced. However, it has been found that when the angle θ increases and exceeds 60 °, the amount of elongation d when the positive electrode grid body 500 is corroded rapidly increases.
When the angle θ is reduced, the amount of elongation d can be suppressed small, but the height dimension T is shortened, and as a result, the weight of the positive electrode grid body 500 is increased, which is an obstacle to reducing the weight of the battery.
[0008]
[Patent Document 1]
JP-A-60-30057 [Patent Document 2]
JP-A-8-203533
[Problems to be solved by the invention]
The present invention relates to an expanded grid used for the positive electrode of a lead-acid battery as described above, in which the grid increases rapidly when the angle θ formed by the grid bone in FIG. 1 exceeds 60 ° in order to reduce the weight of the grid. The purpose of the present invention is to provide a lead-acid battery having excellent life characteristics by using the positive electrode grid to suppress deformation and active material falling off during corrosion.
[0010]
[Means for Solving the Problems]
In order to solve the above-described problem, the invention according to claim 1 of the present invention includes an expanded mesh formed by expanding a lead alloy sheet into a net shape, and a current collector is provided on an upper frame bone provided in contact with the expanded mesh. And a grid body of a lead storage battery in which the current collector is provided eccentrically from the center line of the expanded mesh, wherein the end of the expanded mesh is arranged in the direction of the center line from the current collecting ear of the upper frame bone. And an inclined portion having a reduced height dimension (h) as it approaches the end of the expanded mesh from the collecting ear portion to the portion, and an extension line of the upper end of the inclined portion and an extension of a lower end portion of the upper frame bone. The angle between the line and the line is θ ₁ , and the angle between the lattice bone inclined upward and the lattice bone inclined downward from an arbitrary intersection of the lattice bone and the lattice bone in a unit cell constituting the expanded mesh is θ _2. And the above θ With _two of the 60 ° to 75 °, shows a positive electrode grid of a lead-acid battery, characterized in that the theta ₁ and 2 ° or more.
[0011]
According to a second aspect of the present invention, in the positive electrode grid of the lead storage battery according to the first aspect, the Sn concentration in the lead alloy sheet is 1.2% by mass or more and 2.0% by mass or less. It is a feature.
[0012]
The invention according to claim 3 of the present invention is directed to a lead-acid battery using a positive electrode plate having the structure according to claim 1 or 2 and having a positive electrode plate filled with an active material.
[0013]
According to a fourth aspect of the present invention, there is provided the lead-acid battery according to the third aspect, further comprising an electrode group in which a bag-like separator accommodating the negative electrode plate and a positive electrode plate are stacked.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
A positive electrode grid of a lead storage battery according to an embodiment of the present invention will be described with reference to the drawings.
[0015]
As shown in FIG. 1, the positive electrode grid body 100 of the lead-acid battery according to the present invention has an upper frame bone 101 integrally provided with a current collecting ear 102. The upper frame bone 101 is provided integrally with an expanded mesh 103 for filling an active material (not shown), and the expanded mesh 103 has a lower frame bone 104 corresponding to the bottom of the electrode plate.
[0016]
The expanded mesh 103 is formed by forming a zigzag slit in a lead alloy sheet such as a Pb-Ca-Sn alloy and expanding the slit. The collecting ear 102 is provided eccentrically from the center line L in the width direction of the expanded mesh 103.
[0017]
The height from the collecting ear 102 to the end of the expanded mesh 103 in the portion from the collecting ear 102 to the end of the expanded mesh 103 in the center line L direction is closer to the height from the collecting ear 102 to the end of the expanded mesh 103 (h). Is provided. The angle between the extended line N of the lower end of the upper end of the extension line M and the upper frame bone 101 of the inclined portion 105 to the theta ₁ and 2 ° or more. Further, as shown in FIG. 2, the angle θ ₂ between the lattice bone 106a inclined upward and the lattice bone 106b inclined downward with respect to an arbitrary intersection 107 of the expanded mesh 103 is set to 60 ° or more. As this angle theta ₂ is large, the grating height T increases, if it is possible to reduce the weight of the grid was increased beyond 75 °, since the crack at the intersection portion 107 is generated, 75 ° It is preferable to set the following.
[0018]
In addition, the angle θ ₁ is such that the lattice deformation hardly changes in the range of 6 ° to 7 °. Increasing this angle increases the weight of the lattice and shortens the distance from the negative electrode strap to 7 ° or less. Is preferred.
[0019]
Thereafter, the positive electrode grid 100 is filled with an active material (not shown), aged and dried to form a positive electrode plate, and the lead-acid battery of the present invention can be obtained by using this positive electrode plate.
[0020]
By using the configuration of the present invention described above, even if the positive electrode grid 100 is corroded, it is possible to suppress the deformation of the upper frame bone, the short circuit between the positive electrode and the negative electrode, and the reduction in the life due to the fall of the positive electrode active material.
[0021]
Further, in the configuration of the present invention, since the falling off of the positive electrode active material can be suppressed, the negative electrode plate is replaced with the bag-shaped separator instead of the conventional configuration in which the positive electrode plate is stored in the bag-shaped separator to hold the dropped active material. The stored configuration can be adopted. Thus, in the configuration in which the positive electrode plate is housed in the bag-shaped separator, the problem of damage to the bottom of the bag-shaped separator caused by oxidation by the positive electrode plate can be avoided.
[0022]
Therefore, in the present invention, the configuration in which the negative electrode plate is housed in the bag-shaped separator is the most preferable because both the suppression of the falling of the positive electrode active material and the suppression of the damage to the bottom of the bag-shaped separator can be achieved.
[0023]
Furthermore, it is preferable to use a Pb-Ca-Sn alloy having a Sn concentration of 1.20% by mass or more as a composition of the lead alloy constituting the positive electrode grid 100 of the present invention. In the present invention, the Ca concentration is not specified, but the Ca concentration is set in the range of 0.04% by mass to 0.10% by mass in consideration of the processability during the expanding process.
[0024]
Further, in the present invention, the upper limit of the Sn concentration is not specified, but as in the case of Ca, an increase in the Sn concentration causes cracks or breaks in the expanded network, so that the upper limit of the Sn concentration is set to 2.0% by mass or less. Is preferred.
[0025]
By setting the Sn concentration in the Pb-Ca-Sn alloy used for the positive electrode grid 100 to 1.20 mass% or more, the corrosion resistance of the Pb-Ca-Sn alloy is improved, and the progress of corrosion of the positive electrode grid can be suppressed. This is advantageous in that the life of the lead storage battery can be extended. However, since the tensile strength of the Pb-Ca-Sn alloy is also improved, the stress on the positive electrode grid increases when the positive electrode grid is corroded. When the bending point of the deformation is set at a certain point as in Patent Document 2 described above, stress concentrates at this bending point. In a Pb-Ca-Sn alloy having a Sn concentration of 1.20% by mass or more, the concentrated stress value increases sharply as compared with a Pb-Ca-Sn alloy having a Sn concentration of less than 1.2% by mass. As a result, the deformation of the positive electrode grid body progresses rapidly, the capacity suddenly decreases, and the battery becomes unusable.
[0026]
In the configuration of the present invention, even when the Pb-Ca-Sn alloy having the Sn concentration as described above is used, the rapid deformation of the upper frame bone can be suppressed by dispersing the stress applied to the upper frame bone.
[0027]
【Example】
Next, examples of the present invention will be described.
[0028]
(1) Example 1
Using a rolled sheet of Pb-0.05% by mass Ca-1.8% by mass Sn alloy, an expanded network was formed by a rotary expanding method. Next, the expanded mesh was filled with an active material and punched to form a single electrode plate, which was then aged and dried to obtain an unformed positive electrode plate.
[0029]
In the present example, the positive electrode lattice of the present invention and the positive electrode lattice of the comparative example were produced by changing θ ₁ and θ ₂ of the positive electrode lattice of the above-described embodiment of the present invention. Using these positive plates, a lead-acid storage battery of type 80D26 (JIS D5301) shown in Table 1 was prepared. In this example, the negative electrode plate was housed in a bag-shaped separator made of a microporous polyethylene sheet, and was combined with the positive electrode plate to form an electrode plate group.
[0030]
[Table 1]

[0031]
These batteries were continuously charged at a constant voltage of 14.8 V for 4 weeks in a 40 ° C. atmosphere, and after the charging was completed, the batteries were disassembled and, as shown in FIG. The amount of frame bone deformation (d) was measured. Table 1 shows the percentage of the frame bone deformation (d) obtained for each battery with respect to the frame bone deformation (d3) of the battery 3 of the comparative example as a bone deformation ratio (d ').
[0032]
From the results shown in Table 1, it can be seen that the frame bone deformation amount ratio and the electrode plate bending amount ratio deformation amount ratio can be extremely low at the same time when θ1 is in the range of 2 ° to 7 ° and θ2 is in the range of 60 ° to 75 °.
[0033]
(2) Example 2
Next, regarding the batteries 8 and 18 shown in Table 1 of Example 1, batteries in which the Sn concentration in the lead alloy sheet and the polarity of the electrode plate housed in the bag-shaped separator were changed. Table 2 shows these batteries.
[0034]
[Table 2]

[0035]
For the batteries shown in Table 2, a life cycle test in which charging and discharging were repeated was performed. The test conditions were a 14.8 V constant voltage charge in a 40 ° C. atmosphere for one week, and a constant current discharge at 300 A for 5 seconds in a 25 ° C. atmosphere. These charging and discharging were repeatedly performed, and the point in time when the voltage at the 5th second of discharging decreased to 7.2 V was defined as the number of life cycles. FIG. 4 shows the results of these life tests.
[0036]
From the results shown in FIG. 4, in the region where the Sn concentration in the Pb-Ca-Sn alloy used for the positive electrode grid is 1.20% by mass or more, the life of the battery of the comparative example is rapidly reduced. On the other hand, the battery of the present invention example shows good life characteristics even when Sn is 1.20% by mass or more. Among them, the battery of the present invention in which the negative electrode plate was housed in the bag-like separator exhibited extremely excellent life characteristics.
[0037]
In the battery of the comparative example in which the Sn concentration was 1.20% by mass or more, the deformation of the upper frame bone of the positive electrode grid was concentrated at one point, and the upper frame bone was bent at that point. On the other hand, in the example of the present invention, even with such Sn concentration, the deformation of the upper frame bone was not concentrated at one place, and the deformation was dispersed. Further, as the Sn concentration was reduced to less than 1.20% by mass, the state where the upper frame bone was intensively bent at one location changed to a state where the entire upper frame bone was deformed. Further, as the Sn concentration decreased, the number of life cycles itself decreased. Therefore, according to the present invention, extremely good life characteristics can be obtained even in a region where the Sn concentration is 1.20% by mass or more.
[0038]
In particular, in the present invention, since the amount of the falling-off active material can be suppressed by suppressing the deformation of the positive electrode grid, it is not necessary to store the positive electrode plate in the bag-like separator as in the conventional case. Therefore, it is possible to avoid a problem when the positive electrode plate is stored in the bag-shaped separator, that is, a problem of a short circuit between the positive electrode and the negative electrode due to breakage of the bottom of the bag-shaped separator.
[0039]
【The invention's effect】
As described above, according to the configuration of the present invention, it is possible to provide a long-life lead-acid battery by solving the problem of battery life reduction due to lattice deformation and active material falling off at the time of corrosion. Useful.
[Brief description of the drawings]
1 is a view showing a positive electrode grid body according to the present invention; FIG. 2 is a view showing an expanded mesh; FIG. 3 is a view showing a measurement position of an amount of deformation of an upper frame bone; FIG. 4 is a view showing a life test result; FIG. 1 shows a conventional expanded lattice body.
REFERENCE SIGNS LIST 100 Positive grid member 101 Upper frame bone 102 Current collecting ear 103 Expanded mesh 104 Lower frame bone 105 Inclined section 106 Grid bone 106a Grid bone 106b inclined upward Grid lattice 107 inclined downward 107 Intersection 201 Expanded mesh 202 Cutting line 300 Positive lattice 301 Upper frame bone 500 Expanded lattice body 501 Upper frame bone 502 Expanded mesh 503 Lower frame bone 504 Upper frame bone 505 Current collecting ear 506 Grid bone L Center line M (of expanded mesh 103) Upper end of inclined portion 105 ) Extension line N Extension line (at the lower end of upper frame bone 101)

Claims (4)

An expanded mesh formed by expanding a lead alloy sheet into a mesh is provided, and a current collector is provided on an upper frame bone provided in contact with the expanded mesh, and the current collecting ear is eccentric from a center line of the expanded mesh. A grid body of a lead-acid storage battery provided in a manner extending from the current collecting ear of the upper frame bone to the expanded mesh end in the center line direction, as approaching from the current collecting ear to the expanded mesh end. An inclined portion having a reduced height dimension (h) is provided, and the angle formed by the extension of the upper end of the inclined portion and the extension of the lower end of the upper frame bone is θ ₁ , and in a unit cell constituting the expanded mesh, the angle formed between the lattice bone which is inclined to the lattice bone and lower inclined upwardly from any intersection of the lattice bone when the theta _2, the theta ₂ with a 60 ° to 75 °, the theta ₁ 2 ° or more Positive grid for lead-acid battery. The positive electrode grid body according to claim 1, wherein the Sn concentration in the lead alloy sheet is 1.2% by mass or more and 2.0% by mass or less. A lead-acid battery using a positive electrode plate in which the positive electrode grid according to claim 1 or 2 is filled with an active material. The lead-acid battery according to claim 3, further comprising an electrode group in which a bag-like separator accommodating the negative electrode plate and a positive electrode plate are stacked.

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