WO2014076883A1

WO2014076883A1 - Lead-acid cell

Info

Publication number: WO2014076883A1
Application number: PCT/JP2013/006224
Authority: WO
Inventors: 剛風間; 信典大木; 小島　優
Original assignee: パナソニック株式会社
Priority date: 2012-11-13
Filing date: 2013-10-21
Publication date: 2014-05-22
Also published as: JPWO2014076883A1

Abstract

The present invention provides a lead-acid cell capable of avoiding both the problems of dendrite short circuits and freeze damage in a configuration in which a mat separator is used and the amount of electrolyte is reduced. This lead-acid cell is provided with an electrode plate group (1), an electrolyte, and a cell case (2) for housing the electrode plate group (1) and the electrolyte. The electrode plate group (1) comprises a positive electrode plate (1a), a negative electrode plate (1b), and a mat separator (1c) flanked by the two electrode plates. The ratio (S/P) of the mass (S) of the sulfuric acid in the electrolyte relative to the mass (P) of the active material of the positive electrode plate (1a) is equal to or greater than 0.53. The thickness (T) of the side surface of the cell case (2) parallel to the positive electrode plate (1a) and the negative electrode plate (1b) is 3.5-5.5 mm.

Description

Lead acid battery

The present invention relates to a lead storage battery.

The configuration using a mat separator as a lead-acid battery separator allows a sufficient amount of electrolyte to permeate the mat separator, so the amount of electrolyte used can be reduced compared to a configuration using a plate separator made of polyethylene or the like. Can be reduced. Therefore, the mat separator is an important element in a lead storage battery having a structure that does not perform rehydration such as a sealed lead storage battery. Recently, a configuration using a mat separator has also been adopted in lead storage batteries installed in automobiles, such as for auxiliary equipment of hybrid vehicles installed in places where it is difficult to supplement water.

The above-described lead-acid battery for auxiliary machines plays a role of supplying electric power to various devices mounted on the vehicle even during a period when it is not charged for a long period of time (the vehicle is not driven), so that it easily falls into a relatively deep discharge. Inside the lead-acid battery that is deeply discharged, the discharge product (lead sulfate) and the active material (lead) of the negative electrode plate are easily dissolved in the electrolyte. When charging is started from this state, a dendritic crystal of lead called dendrite is generated on the surface of the negative electrode plate and penetrates the mat separator to reach the positive electrode plate, thereby causing an internal short circuit (hereinafter referred to as this defect). This is called a dendrite short).

In order to eliminate such problems, Patent Document 1 discloses that the ratio S / P of the sulfuric acid mass S of the electrolytic solution to the mass P of the active material of the positive electrode plate is 0.40 or more and 0.52 or less. Discloses a technique for containing an appropriate amount of sodium tetraborate. Patent Document 2 discloses a technique for making the inner dimension of the cell chamber larger than the thickness of the electrode plate group while setting the above-described ratio S / P to 0.48 or more.

JP 2007-035339 A JP 2008-186654 A

In recent years, as hybrid vehicles and the like have been used in cold regions, there has been a concern about the failure (hereinafter referred to as “freezing failure”) of the battery case of the lead-acid battery for vehicles using a mat separator. And it has been found that freezing breakage cannot be sufficiently avoided only by the techniques of

Patent Documents

1 and 2.

The present invention is for solving this problem, and an object thereof is to provide a lead-acid battery capable of avoiding both problems such as a dendrite short circuit and a freezing breakage in a configuration in which the electrolyte is reduced using a mat separator. .

In order to solve the above-described problems, a lead storage battery according to the present invention includes an electrode plate group, an electrolytic solution, and a battery case that accommodates them, and the electrode plate group includes a positive electrode plate, a negative electrode plate, And a ratio S / P of the sulfuric acid mass S to the active material mass P of the positive electrode plate is 0.53 or more, and the positive electrode plate and The thickness T of the side surface of the battery case parallel to the negative electrode plate is 3.5 mm or more and 5.5 mm or less.

According to the present invention, it is possible to provide a lead-acid battery capable of avoiding both a dendrite short-circuit and a freezing breakage in a configuration in which the electrolyte is reduced using a mat separator.

It is the figure which showed the structure of the lead acid battery in one Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram schematically showing a configuration of a lead storage battery according to an embodiment of the present invention.

The lead storage battery includes an electrode plate group 1, an electrolytic solution (not shown), and a battery case 2 for storing them. The electrode plate group 1 includes a positive electrode plate 1a, a negative electrode plate 1b, and a mat separator 1c sandwiched between the two electrode plates. The plurality of electrode plate groups 1 are respectively stored in the cell chambers 2b of the battery case 2 partitioned by the middle partition plate 2a. And it connects with the different polarity of the adjacent electrode group 1 via the connection component 3 (series connection). Further, the opening of the battery case 2 is closed with a lid 4 having a control valve 4a corresponding to each cell chamber 2b. Instead of the control valve 4a, a simple liquid plug may be used.

The lead storage battery of this embodiment has two features. The first characteristic is that the ratio S / P of the sulfuric acid mass S to the active material mass P of the positive electrode plate 1a is 0.53 or more. The second feature is that the thickness T of the side surface (hereinafter referred to as the short side surface 2c) of the battery case 2 parallel to the positive electrode plate 1a and the negative electrode plate 1b is 3.5 mm or more and 5.5 mm or less.

Patent Document 1 states that when the ratio S / P exceeds 0.52, the gas absorption efficiency in the negative electrode plate 1b is lowered, gas generation becomes remarkable, and the reduction of the electrolyte becomes remarkable. However, as a result of intensive studies by the present inventors, it has been found that if the thickness of the short side surface 2c is 3.5 mm or more, the decrease in the electrolyte can be prevented. The inventors of the present invention have the reason that the sufficiently thick short side surface 2c presses the electrode plate group 1 so that the gap in the mat separator 1c, which serves as a passage for the generated gas, is narrowed, and the passing speed of the generated gas is reduced. It is presumed that the gas absorption efficiency has recovered due to the decrease (the generated gas slowly passes through the surface of the negative electrode plate 1b).

However, if the thickness of the short side surface 2c becomes excessively large and exceeds 5.5 mm, the gap in the separator 1c becomes too small (the mat separator 1c is compressed too much), and the positive electrode plate 1a and the negative electrode plate 1b. Too close, dendrite shorts are likely to occur.

On the other hand, when the ratio S / P is less than 5.3, the amount of sulfuric acid in the electrolyte solution becomes too low (too close to the additive-free water), so the freezing point of the electrolyte solution becomes high and used in cold regions. In this case, the electrolyte is more likely to freeze. The electrolytic solution whose volume is increased by freezing compresses the battery case 2 and causes the battery case 2 to freeze and break.

As the active material of the positive electrode plate 1a, lead powder appropriately containing red lead or the like can be used. The active material of the negative electrode plate 1b can appropriately contain barium sulfate, a lignin compound, and the like in addition to the lead powder described above. Glass fiber or polyester fiber can be used as the main raw material for the mat separator 1c.

The ratio S / P in the present invention is calculated from the active material mass P of the positive electrode plate 1a and the sulfuric acid mass S of the electrolyte solution for one electrode plate group 1, but for the entire lead acid battery, the positive electrode plate Even if it is calculated from the mass P of the active material 1a and the mass S of the sulfuric acid in the electrolyte, there is basically no significant difference.

Hereinafter, the effect of the present invention will be described with reference to examples.

(Battery A)
An active material paste is prepared by kneading lead oxide powder with sulfuric acid and purified water, and the active material paste is filled into a continuum of lattice obtained by expanding a lead alloy sheet, and cut into a predetermined size. A positive electrode plate 1a (active material mass P was 80 g per sheet) was produced. On the other hand, an active material paste is prepared by kneading a mixture of lead oxide powder with organic additives, barium sulfate, carbon, etc., using sulfuric acid and purified water, and then expanding the lead alloy sheet. The grid was filled with this active material paste to prepare a negative electrode plate 1b.

An electrode plate group 1 was prepared by disposing a mat separator 1c mainly composed of glass fiber or polyester fiber between 5 positive electrode plates 1a and 6 negative electrode plates 1b.

A plurality of electrode plate groups 1 were respectively stored in cell chambers 2b of a battery case 2 (thickness of the short side surface 2c is 4.5 mm), and different polarities of adjacent electrode plate groups 1 were connected by connecting parts 3. The positive electrode plate 1a of the cell chambers at both ends was connected to a positive terminal, and the negative electrode plate 1b was connected to a negative terminal. The opening of the battery case 2 is sealed with a lid 4, and dilute sulfuric acid that is an electrolytic solution (200 g of sulfuric acid, specific gravity is 1.33 g / ml) is injected from the liquid port. Sealed to produce a 12V28Ah lead acid battery (Battery A, ratio S / P is 0.5).

(Batteries B, C, D, E, F)
By increasing the volume of dilute sulfuric acid compared to battery A (increasing the mass S of sulfuric acid), the ratio S / P was made larger than that of battery A as shown in (Table 1). Batteries B, C, D, E, and F were made.

(Batteries I, J, K, L, M, N)
As shown in (Table 1), except that the short side surface 2c of the battery case 2 is thinner (batteries I, J, K) than the battery D (batteries L, M, N), and the battery D Batteries I, J, K, L, M and N were made in the same manner.

These batteries were evaluated as follows. The results are also shown in (Table 1).

(Dendrite short)
10 batteries under each condition were discharged to 10.5 V at 5.6 A in a 40 ° C. environment (so-called complete discharge), and then overdischarged for 14 days with a load of 10 W. Next, it was left in an open circuit state for 14 days in a 40 ° C. environment. Finally, 15.0 V constant voltage charging (maximum current 25 A, 4 hours) was performed in a 25 ° C. environment, and then the battery under each condition was disassembled. If even one black spot (dendrite) is observed on the side of the mat separator 1c that contacts the positive electrode plate 1a, it is considered that a short circuit (dendrite short) has occurred.

(Freezing damage)
The battery under each condition was charged at a constant voltage of 15.0 V (maximum current 25 A, 4 hours) in a 25 ° C. environment and discharged at 5.6 A for 4 hours. Thereafter, the reaction was allowed to stand for 24 hours in a −40 ° C. environment, and further for 24 hours in a 5 ° C. environment, and was repeated 10 times. After that, the battery case 2 that was visually damaged was considered to have been frozen.

(Reduction of electrolyte)
The battery under each condition was charged with a constant voltage of 14.4 V for 28 days in a 40 ° C. environment. The difference between the initial weight of the battery and the weight after the test was regarded as a decrease amount of the electrolytic solution, and this value was divided by the initial weight of the battery to obtain the decreasing rate of the electrolytic solution.

Contrast batteries A to G. When the ratio S / P is less than 0.53, freezing damage is observed. This is because if the amount of sulfuric acid in the electrolytic solution becomes too low (too close to the additive-free water), the freezing point of the electrolytic solution becomes high, and the electrolytic solution whose volume is increased due to freezing of the electrolytic solution is This is probably because the battery case 2 was pressed and the battery case 2 was frozen. Therefore, it can be seen that the ratio S / P must be 0.53 or more.

If the ratio S / P is increased by increasing the volume of dilute sulfuric acid (increasing the mass S of sulfuric acid), the electrolytic solution may overflow from the battery case 2. Therefore, in order to obtain the same ratio S / P without causing overflow of the electrolytic solution, the specific gravity of the electrolytic solution may be increased. However, if the specific gravity of the electrolytic solution is too large, the viscosity of the electrolytic solution becomes too high, which may reduce the high rate discharge characteristics of the battery, which is not preferable.

Compare battery D and batteries I-N. When the thickness of the short side surface 2c of the battery case 2 is 3.5 mm or more, the decrease in the electrolytic solution is remarkably reduced. This is because when the sufficiently thick short side surface 2c presses the electrode plate group 1, the gap in the mat separator 1c, which serves as a passage for the generated gas, is narrowed, and the passing speed of the generated gas is reduced (the generated gas is a negative electrode). It is considered that the gas absorption efficiency has been recovered by slowly passing through the surface of the plate 1b.

On the other hand, when the thickness of the short side surface 2c exceeds 5.5 mm, the short-circuit occurrence rate increases. This is because when the thickness of the short side surface 2c becomes excessively large, the gap in the separator 1c becomes too small (the mat separator 1c is compressed too much), and the positive electrode plate 1a and the negative electrode plate 1b approach too much. This is probably because dendrite shorts are more likely to occur. Therefore, it can be seen that the thickness of the short side surface 2c must be not less than 3.5 mm and not more than 5.5 mm.

In Embodiment 1 and Examples, a plurality of electrode plate groups 1 are provided and adjacent electrode plate groups 1 are connected in series. However, even when a plurality of electrode plate groups 1 are connected in parallel, the electrode plates Even when only one group 1 is used, the same effect can be obtained.

In addition, the lead storage battery that can obtain the above-described effect usually has an electrolyte solution in which at least a part of the electrode plate group 1 is usually immersed, although depending on the pore volume of the mat separator 1c and the like.

The lead storage battery of the present invention can improve both the balance including other characteristics while avoiding both problems such as dendrite short-circuit and freezing breakage in a configuration in which the electrolyte is reduced by using a mat separator. Therefore, it is extremely useful industrially, such as development of hybrid vehicles for auxiliary machines.

DESCRIPTION OF SYMBOLS 1 Electrode plate group 1a Positive electrode plate 1b Negative electrode plate 1c Mat separator 2 Battery case 2a Middle partition plate 2b Cell chamber 2c Short side surface 3 Connection component 4 Lid 4a Control valve

Claims

An electrode plate group, an electrolytic solution, and a battery case for storing them,
The electrode plate group includes a positive electrode plate, a negative electrode plate, and a mat separator sandwiched between the two electrode plates,
A ratio S / P of a mass S of sulfuric acid in the electrolytic solution to a mass P of the active material of the positive electrode plate is 0.53 or more,
A lead acid battery in which a thickness T of a side surface of the battery case parallel to the positive electrode plate and the negative electrode plate is 3.5 mm or more and 5.5 mm or less.
2. The lead acid battery according to claim 1, wherein a ratio S / P of a mass S of sulfuric acid of the electrolytic solution to a mass P of the active material of the positive electrode plate is 0.67 or less.
The lead acid battery according to claim 1, wherein a plurality of the electrode plate groups are provided, and the adjacent electrode plate groups are connected in series.
The lead acid battery according to claim 1, wherein the electrolytic solution immerses at least a part of the electrode plate group.