JPH08339820A - Negative electrode absorption system seal type lead-acid battery - Google Patents

Abstract

PURPOSE: To lessen elongation and corrosion of a positive electrode grid by touching and pressing a retainer mat to the surface of a paste type positive electrode plate which is composed of an architrave portion and a group of plural thick crosspieces and between the adjoining thick crosspieces of which active material is filled. CONSTITUTION: An upper portion architrave 1, a group of thick crosspieces 2, 2', and a grid lug 3 of a positive electrode plate of a lead-acid battery are formed of lead-calcium alloy. The architraves 4 forming the three edges of a grid are a plastic frame body. Positive electrode active material 6 is continuously filled between adjoining two thick crosspieces 2, 2'. A thin paper-like body 7 made of wood pulp fibers is partly buried in the active material so as to integrate. A separator-cum-electrolyte retaining body such as a retainer mat is touched and pressed to the surface of this paste type positive electrode plate. The group of thick crosspieces 2 are fixed using a plastic frame body 5 having a function as a crosspiece. It is desirable that the pitch of a group of thin crosspieces crossing the group of thick crosspieces 2 is set to be five or more times the pitch of the group of thick crosspieces 2, or the cross section area of the thin crosspiece is set to be one sixth or less times the cross section area of the thick crosspiece 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a negative electrode absorption type sealed lead acid battery using a paste type positive electrode plate.

[0002]

2. Description of the Related Art Negative electrode absorption type sealed lead-acid batteries have been rapidly used for charging / discharging applications such as electric vehicles and for floating charging applications such as stationary applications, because they are maintenance free and do not require water replenishment. However, in both applications, the battery has a shorter life than the conventional battery, that is, a battery using a lead-antimony alloy and a large amount of flowing electrolyte. The main causes are corrosion and elongation of the positive electrode grid except for the dry-up caused by the decrease of water in the electrolytic solution.

As is well known, the function of the lattice is to retain the active material and to collect charge / discharge current, that is, to conduct electricity. The former can be replaced by other means such as a plastic frame or a clad tube. However, the latter function of collecting electricity can be performed only with the lead alloy material because dilute sulfuric acid is used as the electrolytic solution.

On the other hand, in the sealed lead-acid battery, it is essential to use a lead-calcium alloy in the grid in order to suppress the generation of hydrogen gas due to self-discharge as much as possible.
In this alloy, the molten metal solidifies in a narrow temperature range of 327 ± 1 ° C. Therefore, during casting of the lattice, the molten lead alloy is cooled from the surface of the mold and solidification begins, and the portion having a large heat capacity, that is, the intersection of the vertical and horizontal ridges of the lattice is finally solidified. Since the volume of the lead alloy shrinks by 3-5% when it solidifies,
In the lead-calcium alloy, voids are formed at the intersections of the vertical and horizontal ridges of the finally solidified lattice, and casting defects are concentrated. For lead-antimony alloys, 327 ° C to 252 ° C.
In a wide temperature range of ℃, lead-rich primary crystals solidify in a dendritic manner to determine the shape and size of the lattice, and at 252 ℃, the alloy with the eutectic composition solidifies between the dendritic primary crystals. Due to this, the vacancies are uniformly distributed among the primary crystals, and the vacancies themselves are fine, which has little adverse effect on corrosion and elongation of the lattice.

Further, the elongation of the lattice is the elongation due to the corrosive product of lead having a large molecular volume which is generated and adheres to the surface of the cauldron and the expansion due to the corrosion product between the alloy grains. The former is proportional to the length of the perimeter of the coffin and inversely proportional to the cross-sectional area, so the thicker the coffin, the lesser the growth. (Elongation = K (Stretching force /
(Tensile strength) = 2πrk ′ / πr ² = 2k ′ / r, r is a radius when the cylinder is assumed to be a cylinder, and K and K ′ are constants). The latter is larger in the holes existing in the lattice, that is, in the lattice having more defects.

From the above, in order to reduce the elongation of the lead-calcium alloy lattice, the vertical shaft is made thick and the horizontal shaft is made thin and small so that the intersections of the two are reduced, ideally at all. It is necessary. This lattice shape is the same as the structure of the core metal group of the clad electrode plate, but in the clad type electrode plate, not only the flat retainer mat cannot be used as the electrolyte holding body and separator, but also the paste type electrode plate. It is more expensive than the plate because it is inferior in productivity, and if the core bar breaks in the middle, the lower part is not used for charging and discharging and the performance deteriorates, so it is practically used as a sealed lead acid battery. It has not been.

[0007]

Means for Solving the Problems The present invention comprises a frame portion made of a lead alloy and a group of a plurality of talcum flakes that extend in a substantially constant direction, and an active material is provided between two adjacent balconies. Is contacted and pressed with a separator / electrolyte holder such as a retainer mat on the surface of a paste-type positive electrode plate using a lead-calcium alloy grid that is continuously filled, and the Taiki group,
Fixing with a plastic frame that intersects with it, and further crossing and fixing with the Taiki, the pitch of the lead alloy fine cauldron is 5 times or more the pitch of the Taoki cauldron, or the cross-sectional area of one of the casket By 1/6 or less of the cross-sectional area of one of the Tatsuki, the expansion and corrosion of the positive electrode grid made of lead-calcium alloy was reduced, and the life of the sealed lead-acid battery was extended. It is a thing.

[0008]

The present invention will be described with reference to the drawings. FIG. 1 is a partially cutaway sectional view of a positive electrode plate used in the lead acid battery of the present invention,
In FIG. 1, reference numeral 1 is an upper frame of the lattice, 2 and 2 ′ are talons cast integrally with the frame 1, and 2 and 2 ′ are arranged in parallel and extend downward. Reference numeral 3 denotes a lattice ear, and the upper frame 1, the Taiki group 2 and 2 ', and the lattice ear 3 are all lead-calcium alloys. 4, 4 ′ and 4 ″ are plastic frames, which are picture frames that form the three perimeters of the lattice. 5 and 5 ′ are plastic frames, which are arranged in the lateral direction of the lattice, and the Taiki group 2 and 2 'Is held by holding it and is also integrated with the plastic side frame 4 and 4', which is an arrangement equivalent to a normal horizontal board. 6 is a positive electrode active material, and two adjacent 7 is thinly filled with wood pulp fibers, for example, a thickness of 1
It is a paper-like body having a size of 0 to 30 μm and is partially embedded in the active material 6 to be integrated.

In the above-mentioned embodiments, the frame made of lead alloy is shown only in the upper part, but the frame may be composed of two sides such as the upper part and the lower part or the upper part and one side part, or the four edges may be entirely made of the lead alloy. . Further, the Taiki group may be arranged not only in the vertical direction but also in the horizontal direction or only in the diagonal direction. Further, the cross-sectional shape is not limited to the circular shape shown in the figure, but is preferably an oval shape, a square shape, a rhombus shape, or the like shape from the center point, but may be a triangular shape. The plastic frames 5 and 5'having the function of the horizontal board function to facilitate the filling of the paste by fixing the group of the horizontal boards, but this is not always necessary.

Further, the plastic frames 5 and 5'may be replaced by a lead-calcium alloy rod group.
However, in this case, in order to reduce the number of intersections between the Taiki and the Hozo, the pitch of the Hozo groups should be 5 times or more the pitch of the Taiki groups, or the heat capacity of the intersections should not be increased. For this reason, the cross-sectional area of one piece of thin cotton is made negligibly smaller than the cross-sectional area of one piece of large cotton. 1/6 for a specific example
The following is desirable. Experimental data will be shown later.

The positive electrode active material 6 is provided between two adjacent Taiki boards,
It needs to be filled continuously. This is because the lattice of the present invention is basically composed only of the groups of Taiki that are arranged in parallel. Therefore, if a porous material or the like is placed in the active material between the Tatsuki, the electron conduction This is because when the Tatsuki is corroded at the middle part and cut, the lower part of the cut part cannot participate in charging and discharging. If the active material is continuous between Taiki, even in the above case, the lower part of the cut portion can be charged and discharged by conducting the active material.

In the grid shown in the figure, since the horizontal axis is extremely small, it is possible to prevent the paste from falling off by applying a paper-like body made of various materials immediately after filling the paste.
Workability is improved.

FIG. 2 shows a typical conventional grating,
4.4 "and 4'are the four edges of the lattice frame, 3 are the lattice ears, 2
And 2'is a thick vertical group, and 5 and 5'is a thin horizontal group. The pitch of the horizontal row group is generally smaller than the pitch of the vertical row group, but in the case of a vertically long grid or the like, the pitch of the horizontal row group is three times or less than the pitch of the vertical row group. See also 1
The cross-sectional area of a book is smaller than the cross-sectional area of a vertical one, 2/3 to 1
Those within the range of / 4 are used.

Next, a prototype grid and the results of a high temperature float charge life test of a sealed lead-acid battery using the grid as a positive electrode plate are shown.

Prototype grid A As shown in FIG. 1, the grid thickness is 4.8 mm, and the vertical cauldron made of a lead-calcium alloy is a rod shape having a diameter of 3 mm.
Frames on both sides and the lower part, and two horizontal boards are polypropylene frame bodies, and the Taiki group and the plastic frames are fitted and fixed as shown in FIG.

Prototype grid B has four circumferences and a frame of lead-calcium alloy. The vertical sword bar has a rod shape with a diameter of 3 mm, the pitch is 9 mm, and the horizontal sword bar has a rod shape with a diameter of 1.2 mm. The vertical and horizontal groups and the horizontal narrow channels are made by casting together with the frame.

The conventional lattice is shown in FIG. 2, in which the pitch of the fine cauldron is 3/5 of the pitch of the large casket, the cross-sectional area of one fine cauldron is 1/3 of the cross-sectional area of one large casket. Is. A battery was prototyped using the above three types of grids. Four positive electrode plates and five negative electrode plates each having a thickness of 4.0 mm were used, and a retainer mat having a thickness of 2.5 mm was used as a separator. The 20-hour rate discharge capacity of this battery was 28 Ah. Float condition is 50
A constant voltage charge of 2.35 V / cell was performed in a water tank at ℃. The table shows the transition of the 20-hour rate capacity every three months.

[0018]

[Table 1] After the float test was completed, the battery was disassembled and the state of the positive electrode plate was examined. As a result, the elongation of the positive electrode plates A and B according to the present invention was 2 to 3% in both the longitudinal and lateral directions. In the conventional type electrode plate, although the testing facility was 12 months and was shorter than 18 months of the electrode plate according to the present invention, the deformation due to elongation was large at 8% in the transverse direction and 5% in the longitudinal direction. Further, in the conventional battery, the active material of the positive electrode plate was easily removed, but that of the electrode plate of the present invention had good adhesion to the Taiki group. In the positive electrode grid B, the horizontal shaft was corroded and activated.

[0019]

INDUSTRIAL APPLICABILITY The lead-acid battery of the present invention can reduce the elongation and corrosion of the positive electrode grid made of a lead-calcium alloy to prolong the service life of the sealed lead-acid battery, which is of great industrial value.

[Brief description of drawings]

FIG. 1 is a partially cutaway sectional view of a positive electrode plate used in a lead acid battery of the present invention.

FIG. 2 is a diagram showing a conventional lead-acid battery grid.

[Explanation of symbols]

 1 Upper frame of the lattice 2 Tatsuki 3 Lattice ear 4 Plastic frame 5 Plastic horizontal 6 Positive active material 7 Paper

Claims (3)

[Claims] 1. A frame portion made of a lead alloy and a plurality of Taiki casks extending side by side in a substantially constant direction, wherein an active material is continuously filled between two adjacent Taoki casks. A separator / electrolyte holder such as a retainer mat abuts on the surface of the paste type positive electrode plate using the lead-calcium alloy grid.
A negative lead absorption type sealed lead-acid battery characterized by being pressed. 2. The negative electrode absorption type sealed lead acid battery according to claim 1, wherein the Taiki group is fixed by a plastic frame body intersecting with the Tatsuki group. 3. The pitch of the fine-groove group made of a lead alloy that crosses and is fixed to the large-groove group is 5 times or more the pitch of the large-groove group, or one cross-sectional area of the fine-groove group is larger than that of the large-groove group. 1 / of one cross-sectional area
The negative electrode absorption type sealed lead acid battery according to claim 1 or 2, which has 6 or less.