JP2003208898A - Lead-acid battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lead-acid battery having the excellent charge recovering ability after a deep discharge as a failure of a pure lead grid, while maintaining the excellent trickle service life performance of the pure lead grid. <P>SOLUTION: A grid formed by punching or expanding a sheet formed with lead-tin group alloy plate layer in at least one surface of a pure lead (99.9% or more) plate is used for a positive electrode plate, and when thickness ratio of the lead-tin alloy layer in relation to the sheet thickness is X(%) and a tin content ratio in relation to the weight of the lead-tin alloy layer is Y (mass %), X and Y are set to satisfy 0.5≤X≤40, desirably, 0.5≤X≤30 and 0.5≤Y≤-0.625X+50. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a lead storage battery.

[0002]

2. Description of the Related Art Applications of lead-acid batteries are generally divided into so-called trickle applications (float applications) in which charging is performed at a constant voltage and discharging when necessary, and so-called cycle applications in which discharging and charging are repeated. The former cause of deterioration of lead-acid batteries in trickle applications is corrosion of the positive electrode grid. This is because the alloy used for the lattice material is formed at grain boundaries and the grain boundaries are selectively corroded during charging. As a countermeasure, U. S. P. It has been proposed to use a grid body obtained by processing a pure lead sheet for 3862861.

Unlike lead alloys, the grain boundaries of pure lead are not clear, so the above problems do not occur, and an excellent trickle life can be obtained. However, when pure lead is used for the grid, it has a drawback that the capacity does not recover even if it is charged in cycle applications, especially when deep discharge is performed. As a measure against this, a method of using a grid obtained by punching or expanding a sheet of lead-tin alloy by rolling, instead of pure lead, is disclosed in U.S. Pat. S. P. 5120620. This method improves the charge acceptance property after deep discharge, but since it is a lead-tin alloy, it has grain boundaries, and the corrosion of the positive electrode lattice progresses during trickle life, which is shorter than that of pure lead lattice. There's a problem.

[0004]

SUMMARY OF THE INVENTION The problem to be solved by the present invention is to maintain the excellent trickle life performance of the pure lead grid as described above, while recovering the charge after deep discharge which is a drawback of the pure lead grid. It is to provide a lead acid battery having excellent properties.

[0005]

As means for solving the problems, according to claim 1, a sheet having a lead-tin alloy layer formed on at least one of the surfaces of a pure lead (99.9% or more) plate is provided. The positive electrode plate is characterized by using a lattice body formed by punching or expanding.

The grid body formed by punching or expanding a pure lead sheet shows excellent performance under continuous charging conditions, but has a drawback of poor charge recovery characteristics in the case of deep discharge. On the other hand, the inventor of the present application has found that the charge recovery property does not decrease even if deep discharge is performed by forming a lead-tin alloy layer on at least one surface of the sheet.

According to claim 2, when the ratio of the lead-tin alloy layer to the total thickness of the sheet is X (%) and the tin content of the lead-tin alloy layer is Y (mass%), X, Y
Is the following equation, 0.5 ≦ X ≦ 40 and 0.5 ≦ Y ≦ −0.62
It is characterized by satisfying 5X + 50.

The inventor of the present application has found that the charge recovery characteristic after deep discharge is improved by forming a lead-tin alloy layer on at least one surface of a pure lead sheet. On the other hand, the thickness ratio of the integrated lead-tin-based alloy layer and the sample in which the tin content was changed with respect to the lead-tin-based alloy were prepared, and the results were tested. As a result, the ratio of the lead-tin-based alloy layer to the sheet thickness X (%), the lead-
When the tin content of the tin-based alloy layer is Y (mass%), 0.5 ≦ X ≦ 40 and 0.5 ≦ Y ≦ −0.625X
It has been found that when +50 is satisfied, excellent charge recovery characteristics for deep discharge can be more remarkably obtained while having the effect of pure lead of the present invention.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below based on Examples.

In this embodiment, a cylindrical control valve type lead storage battery will be described in which positive and negative electrode plates and a separator are spirally wound and inserted into a cylindrical battery case by utilizing the soft characteristics of a pure lead sheet. [Battery A] (product of the present invention) A pure lead (99.99%) plate having a thickness of 10 mm and a thickness of 0.4
mm lead-10 mass% tin alloy plates were overlaid and rolled to form an integrated sheet having a thickness of 0.6 mm. By punching this sheet, a lattice having 5 mm × 7 mm grids was manufactured.

In the above lattice, t-PbO, Pb ₃ O ₄ ,
A positive electrode plate was manufactured by applying a mixed powder of metal Pb to which paste was added by adding dilute sulfuric acid.

The negative electrode plate is made of pure lead (lead: 99.99% by mass).
A grid body made of a sheet was used, and a paste-like powder prepared by adding dilute sulfuric acid to a mixed powder of t-PbO and metal Pb was applied to this.

The electrode plate thickness is 0.9 mm for both positive and negative electrode plates.
And

A combination of these positive and negative electrode plates and a glass separator is spirally wound by applying a high compression force (about 100 kPa) to form an element (a component in which the positive and negative electrode plates and the separator are superposed is referred to as an element). This element was stored in a cylindrical container having a diameter of 49 mm and a height of 100 mm, and the discharge capacity (rated capacity) at a rate of 5 hours was 1
A 0 Ah cylindrical valve regulated lead-acid battery was manufactured.

The separator has an average diameter of about 1 μm.
Of glass fiber of 20% by mass, silica having a thickness of about 0.9 mm and porosity of about 91% is used.
The thickness was 0.8 mm when compressed under a load of 20 kPa.

As an electrolytic solution, a specific gravity of 1.24 (at 20 ° C.) in which 25 g / l of sodium sulfate is dissolved in dilute sulfuric acid.
After injecting about 115g into the storage battery container,
The battery case was formed. Here, the battery case formation refers to a process of forming an unformed element in a battery case and injecting an electrolytic solution.

A storage battery manufactured by the above configuration and method is designated as A.

In order to show the excellent characteristics of the storage battery A of one example according to the present invention, a comparative test with a conventional product was conducted. The storage battery used for comparison and comparison at that time is specifically shown. [Battery B] (Comparative Example) A pure lead (Pb: 99.99 mass%) plate was rolled to form a 0.6 mm-thick sheet, and a grid body manufactured by the same method as described above was used for the positive electrode plate. A storage battery B was made in the same configuration as the storage battery A. [Rechargeable Battery C] (Comparative Example) A grid body manufactured by a method similar to the above from a sheet having a thickness of 0.6 mm obtained by rolling a 99.0 mass% lead-1.0 mass% tin alloy plate was used as a positive electrode plate. A storage battery C was manufactured in the same manner as the storage battery A except for the above.

For the above three types of storage batteries, comparative tests of charge acceptance characteristics and trickle life after deep discharge were conducted. The results are shown below. [Charge acceptance characteristics after deep discharge] (Test conditions) The above storage battery was cut off at a final voltage of 1.A at a current of 2A.
After discharging to 7 V, a resistance of 100Ω was further connected for 14 days to put the storage battery in a deep discharge state. After that, the storage battery from which the resistance has been removed is allowed to stand for 16 hours in an environment of 0 ° C., and then a constant voltage charge of 2.4 V (limit current 50 A) is applied for 10
It was performed for a minute, and the change of the charging current at this time was observed. (Test Results) The test results are shown in FIG.

In the storage battery B using pure lead, the charging current changes to 0 A during charging for 10 minutes and is hardly charged,
The charge acceptance characteristics were poor. On the other hand, in the storage battery A of the present invention and the storage battery C using only the lead-tin alloy, the charging current flowed and the charge acceptance characteristics were good.

From these test results, it is found that the presence of tin in the positive electrode grid is effective for improving the charging characteristics after deep discharge. In particular, the positive electrode grid of the storage battery A of the present invention has a smaller tin content than the storage battery C, but the presence of tin is more effective because the tin is concentrated in the portion in contact with the positive electrode active material. It can be said that it worked. [Trickle (float) life test] (Test conditions) The above storage battery is constantly charged at a trickle charge voltage of 2.275 V in a gas phase at an environmental temperature of 60 ° C.
It is taken out every month and the discharge current is 10 A (the final voltage is 1.0
The capacity test was performed in V). (Test Results) The test results are shown in FIG.

In the storage battery C using only the lead-tin alloy,
Although the capacity at the 5th month fell below 50% of the initial capacity, the storage battery A and the storage battery B using pure lead maintained 50% or more of the initial capacity at the 10th month.

After the test, the storage battery was disassembled and the positive electrode plate was examined. As a result, the intergranular corrosion, which is a feature of the alloy lattice in the storage battery C, progressed considerably, but the grain boundaries of the lattice in the storage batteries A and B were significantly increased. Almost no corrosion was observed.

As is clear from these test results, the positive electrode grid of the storage battery A is obtained by stacking a lead-10% by mass tin alloy plate on a pure lead (Pb: 99.99% by mass) plate and rolling it. Since it is made of a single sheet, the tin is partially concentrated on the surface part in contact with the active material, unlike the case where only the lead-tin alloy is rolled, and there is much pure lead in other parts. Therefore, it is considered that the effect of pure lead on the trickle life was effectively obtained. [Rechargeable batteries D-1 to K-5] Next, in the configuration of the rechargeable battery A, the test results were obtained regarding the thickness of the lead-tin alloy layer to be superimposed on the pure lead sheet and the appropriate range of the tin content with respect to the lead-tin alloy. It will be explained based on. [Effects of lead-tin alloy layer thickness and tin content on battery performance] (Test conditions) Lead relative to total thickness of integrated sheet-
In order to investigate the influence of the thickness ratio of the tin alloy layer and the tin content per weight of the lead-tin alloy, the tin content relative to the lead-tin alloy was 0.3% by mass, 0.5% by mass, and 1% by mass. A lead-tin alloy plate containing 10% by mass, 20% by mass, 25% by mass, 30% by mass, 40% by mass, 45% by mass, and 50% by mass was rolled to a thickness of 0.03 mm, 0.
05mm, 0.11mm, 0.42mm, 2.5mm,
Sheet materials of 4.3 mm, 6.7 mm and 8.2 mm were produced. And this lead-tin alloy sheet material and thickness 1
By stacking 0 mm pure lead (Pb: 99.99 mass%) plates and rolling them to a thickness of 0.6 mm, the thickness ratio of the lead-tin alloy layer to the sheet thickness and the lead-tin alloy layer were measured. A sheet in which a pure lead plate having a different tin content and a lead-tin alloy plate were integrated was manufactured.

Next, these sheets are punched out and 5 mm
A positive electrode grid having squares of 7 mm was manufactured, and using them as a positive electrode plate, 29 types of storage batteries (storage battery D-1 to storage battery K-5) were manufactured. In these storage batteries, the configuration other than the positive electrode grid was the same as that of the storage battery A.

The thickness ratio X (%) of the lead-tin alloy layer to the total sheet thickness of the positive electrode grid used in the storage batteries D-1 to K-5 and the Sn content Y (of the lead-tin alloy layer Mass%) is shown in Table 1 and Table 2.

[0027]

[Table 1]

[Table 2]

With respect to these 29 types of storage batteries, a charge acceptance characteristic test after deep discharge and a trickle life test were conducted. Both tests are under the same conditions as when the above-mentioned comparative test of the storage batteries A, B and C was performed.

The test results are shown below.

[0030]

[Table 3]

[Table 4]

In Tables 3 and 4, the results of the charge acceptance characteristic test after deep discharge and the trickle life test were evaluated according to the following criteria. That is, the case where the charging current flows (that is, the charging can be accepted) between the start of the test and the end of the test is determined as “good”. (Result of charge acceptance characteristic test after deep discharge) ○: Good charge acceptance characteristic ×: Poor charge acceptance characteristic (trickle life test result) ○: 10-month discharge capacity in trickle life test 50% or more of initial capacity x: discharge capacity at 10 months in trickle life test is less than 50% of initial capacity Next, the value of X is taken on the horizontal axis and the value of Y is taken on the vertical axis. Figure 3
In Table 1, the good ones in both the charge acceptance characteristic test after deep discharge and the trickle life test are shown by ◯, and the bad ones in either test are shown by x.

In FIG. 3, the lead-acid battery located in the region of 0.5 ≦ X ≦ 40 and 0.5 ≦ Y ≦ −0.625X + 50 has an excellent trickle life performance and, after a good deep discharge, is obtained. It became clear that it exhibits charge acceptance characteristics.

Further, the results of the above trickle life test were re-evaluated according to the following criteria.

◯: The discharge capacity at 10 months in the trickle life test is 70% or more of the initial capacity. ×: The discharge capacity at 10 months in the trickle life test is less than 70% of the initial capacity. The results are shown in Table 5. And shown in Table 6.

[0035]

[Table 5]

[Table 6]

Based on the results of this re-evaluation, those that were good in both the acceptance characteristic test and the trickle life test are marked with a circle, and those that were defective in either one of the tests are marked with a cross. And shown in FIG.

In FIG. 4, the lead-acid battery located in the region of 0.5 ≦ X ≦ 30 and 0.5 ≦ Y ≦ −0.625X + 50 has an excellent trickle life performance and, after a good deep discharge, a good result. It became clear that it exhibits charge acceptance characteristics.

In FIG. 3, X <0.5 and Y <0.
In the region of No. 5, the charge acceptance characteristics after deep discharge are poor. This means that in these areas lead-
Since the thickness of the tin-based alloy layer is thin or the tin content in the lead-tin-based alloy layer is low, the disadvantage of the pure lead positive electrode grid, which is the inferior charge acceptance property after deep discharge, is sufficiently solved. It is thought that it was because I did not get.

Also, X> 50 and Y> -0.625X
In the +50 region, the trickle charge life characteristic is poor. This is because, in these regions, the thickness of the lead-tin alloy layer and the tin content are excessive, and as a result of the progress of intergranular corrosion, the conductivity remaining in the positive electrode grid that affects the trickle charge life. It is considered that the route (non-corrosion part) became narrower.

Therefore, the lead-based on the total thickness of the sheet
Regarding the thickness ratio X of the tin-based alloy layer, in order to improve both the trickle life performance and the charge acceptance property after deep discharge, 0.5 ≦ X ≦ 40, more preferably 0.5 ≦ X ≦ 40. It is preferable that X ≦ 30. From the same viewpoint, regarding the tin content Y per mass of the lead-tin alloy layer, 0.5 ≦ Y ≦ −0.625X + 50 is preferable. Furthermore, the above X and Y are set to 0.5 ≦ X ≦ 4.
0 (more preferably 0.5 ≦ X ≦ 30) and 0.5 ≦ Y ≦
It can be said that the most appropriate value is a value within the area divided by -0.625X + 50.

As described above, the positive lead plate is a grid body made of an integrated sheet obtained by stacking a lead-tin alloy plate on a pure lead (99.99 mass% or more) plate and rolling it. Thus, it was found that it is possible to obtain a valve-regulated lead-acid battery that has excellent trickle life performance and that does not cause a problem in charge acceptance characteristics after deep discharge.

In the above embodiment, a lead-tin alloy containing tin in an amount of 0.5 to 50 mass% was used as the lead-tin alloy, but the presence of tin improves the charge acceptance characteristics after deep discharge. Since it contributes, a lead alloy containing tin and another metal component such as a lead-tin-calcium alloy may be used. The tin content Y (mass%) at this time also needs to satisfy the relationship of 0.5 ≦ Y ≦ −0.625X + 50.

In the above embodiment, the effectiveness of the present invention has been described for the cylindrical control valve type lead storage battery, but the effect is not obtained only in the control valve type lead storage battery.
Since the effect is caused by the positive electrode plate, it goes without saying that the same effect can be obtained by using a similar positive electrode plate even in a so-called open-type lead acid battery in which a fluid is present.

Further, in the above embodiment, the lead-tin alloy layer is integrated with the layer made of the pure lead plate by rolling. However, as a method of providing the lead-tin alloy layer on the surface of the pure lead plate, For example, a chemical vapor deposition method, a physical vapor deposition method, a diffusion permeation method, an electrochemical plating method, or the like can be used.
However, of these methods, the rolling method is the simplest, the cost is low, and the mass productivity is excellent.

[0045]

As described above, pure lead (99.99) is used.
%) By using a grid formed by punching or expanding a sheet with a lead-tin alloy plate layer on at least one of the plate surfaces for the positive electrode plate, excellent trickle life performance and charging after deep discharge are achieved. It is possible to obtain a lead storage battery having no problem in acceptability, and in particular, the thickness ratio of the lead-tin alloy layer to the sheet thickness is X (%), and the tin content in the lead-tin alloy layer is Y (mass%). When I did
By satisfying 0.5 ≦ X ≦ 40, preferably 0.5 ≦ X ≦ 30 and 0.5 ≦ Y ≦ −0.625X + 50, the above effect can be obtained more remarkably, and its industrial value is extremely large. .

[Brief description of drawings]

[Figure 1] Charge acceptance characteristic test after deep discharge

[Fig. 2] Trickle (float) life test

FIG. 3 is a relationship between the thickness ratio of the lead-tin alloy layer to the total thickness of the integrated sheet and the tin content (mass%) of the lead-tin alloy layer, and the storage battery performance.

FIG. 4 is a view showing a result of re-evaluating the test result of FIG. 3 by increasing an evaluation criterion for a good trickle life of a storage battery.

Claims (2)

[Claims] 1. A positive electrode plate comprising a grid body formed by punching or expanding a sheet having a lead-tin alloy layer formed on at least one surface of a pure lead (99.9% or more) plate. And lead acid battery. 2. When the ratio of the lead-tin alloy layer to the total thickness of the sheet is X (%) and the tin content of the lead-tin alloy layer is Y (mass%), X and Y are as follows: Expression, 0.5 ≦
The lead storage battery according to claim 1, wherein X ≦ 40 and 0.5 ≦ Y ≦ −0.625X + 50 are satisfied.