JPH08287942A - Manufacture of electrode for retainer sealed lead-acid battery - Google Patents

Abstract

PURPOSE: To provide a manufacturing method of a electrode for a retainer sealed lead acid battery by which service life performance of a battery, particularly, high rate discharging performance can be improved. CONSTITUTION: A electrode press after paste is filled is performed at least two or more times by a press machine, and a difference in a recess-projection on a press machine surface on and after second time is made samller than that of first time. A difference in a recess-projection of the press machine surface on and after second time is set not more than 0.1mm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved method for manufacturing a retainer-type sealed lead-acid battery electrode plate.

[0002]

2. Description of the Related Art Most of the sealed lead-acid batteries currently produced have a mat-shaped separator (glass separator) made of fine glass fibers inserted between a positive electrode plate and a negative electrode plate. A battery of the type that retains the sulfuric acid electrolyte necessary for charging and discharging (hereinafter referred to as the retainer type),
Taking advantage of its features such as no maintenance, no leakage, and position-free, this battery is used as a backup power source for portable devices, cordless devices, computers, large stationary batteries, and for starting the engine of automobiles. It's coming.

Further, the retainer-type sealed lead-acid battery has been applied to applications such as electric vehicles, and high-rate discharge performance has come to be emphasized.

In the retainer type, the electrolytic solution is held only by the electrode plate and the separator, and in order to improve the battery performance, it is necessary to improve the contact state between the electrode plate and the separator. For that purpose, it is necessary to strongly press the electrode plate surface. However, even if the battery is assembled with a sufficiently high degree of compression, the electrode plate cannot be pressed uniformly unless the thickness of the electrode plate is uniform. Further, even if the thickness of the electrode plate is uniform, if the surface of the electrode plate is not smooth, it is impossible to realize uniform pressing and good contact between the separator and the electrode plate. That is, if there is a portion where the separator and the electrode plate are not in good contact with each other or a portion where the degree of compression is low, the deterioration of the active material in that portion and the accumulation of lead sulfate will progress with the cycle, and the battery performance will deteriorate.

[0005]

According to the present invention, an electrode plate press after paste filling is performed at least twice with a pressing machine, and after the first press is finished, the unevenness is smaller than that of the first press roller, Optimum unevenness is 0.1 m
It is intended to improve the life performance by using a smooth electrode plate manufactured by pressing the second and subsequent times using a press roller of m or less. The following examples show some of the results.

[0006]

EXAMPLE A grid was filled with a predetermined amount of paste according to a usual manufacturing method, and in the subsequent electrode plate pressing process, the press shown in Table 1 was performed once, twice or three times, and then aged. Then, an unformed electrode plate was manufactured.

[0007]

[Table 1]

These electrode plates (10 positive electrode plates, 11 negative electrode plates)
Sheet) and a fine glass separator, about 63 Ah
(3hR) -12V retainer type sealed lead acid battery (A ~
I) was manufactured according to the usual manufacturing method. During the production of the battery, a spacer was used so that the force required to insert the element into the battery case was 20 kg.
The specific gravity of the electrolyte is generally 1.300 for EV.
Since sulfuric acid having a specific gravity of (20 ° C.) to 1.340 (20 ° C.) is used, the average value thereof is 1.320 (20
(° C.) was used.

After measuring the 3CA discharge capacity of these batteries,
The discharge depth was set to 80%, and the pattern was subjected to a life test of a pattern in which 110% of the discharge amount was charged at a constant current. 3C during life test
The transition of the A discharge capacity is shown in FIG. The life was judged when the 3CA discharge capacity reached 80% of the initial value.

A battery using the conventional electrode plate pressing method A is
It reached the end of its life in about 200 cycles. It is considered that this is because the electrode plate was not evenly applied with a uniform pressing force because the electrode plate thickness was not uniform, and because the electrode plate surface was not smooth, there was a portion where the contact with the separator was bad.

The batteries using the electrode plate pressing methods B and C had a life of about 500 cycles. This is because the electrode plate thickness was made uniform by performing the electrode plate pressing twice or more, but the contact with the separator was poor because the electrode plate surface was not smooth,
It is considered that since the electrode plate was not uniformly pressed, the softening of the active material in the part where the pressure was small occurred as the cycle proceeded.

Batteries using the electrode plate pressing methods D, E and F exhibited good life performance (700 cycles or more).
This is because the electrode plate is pressed twice or more, and the unevenness of the press roller surface after the second time is smaller than that of the first time.
It is also considered that the contact with the separator was improved.
Especially, the unevenness of the surface of the press roller after the second time is 0 m.
Those with m showed the most favorable capacity transition.

A battery using the electrode plate pressing method G has about 30
It reached the end of life at 0 cycle. Since the electrode plate was pressed twice, the electrode plate thickness was uniform, but the electrode plate surface was not smooth, so the contact with the separator was poor, and the active material in the part with poor contact deteriorated. it is conceivable that.

The battery using the electrode plate pressing methods H and I had a life of about 400 cycles. This is because when the unevenness of the surface of the first press roller is reduced, the electrode plate surface becomes smooth, but the air bleeding during pressing deteriorates and the filled paste is taken by the roller. It is considered that the active material could not be pressed firmly because the pressure could not be increased, and the active material was softened as a whole.

As a result of disassembling all the batteries after the life test, all the active materials of the positive electrode plates subjected to the electrode plate pressing other than D, E and F had a large degree of softening. Even when the second and subsequent electrode plates are pressed with a flat plate press,
It exhibited a good life performance equivalent to that of electrode plate pressing method F.

[0016]

As described above, the method of manufacturing the retainer type sealed lead acid battery electrode plate of the present invention is
In particular, it improves high-rate discharge performance, and its industrial value is great.

[Brief description of drawings]

FIG. 1 is a diagram showing changes in 3CA discharge capacity.

Claims (5)

[Claims] 1. A method of manufacturing a retainer-type sealed lead-acid battery electrode plate, which comprises pressing the electrode plate after filling the paste with a pressing machine at least twice or more. 2. The method of manufacturing a retainer-type sealed lead-acid battery electrode plate according to claim 1, wherein the electrode plate is pressed by a roll-shaped press. 3. The method for producing a retainer-type sealed lead-acid battery electrode plate according to claim 1, wherein the second and subsequent electrode plate presses are performed by a flat plate-shaped press. 4. The unevenness of the surface of the press machine after the second time is
The method for producing a retainer-type sealed lead-acid battery electrode plate according to claim 1, 2 or 3, wherein the electrode plate is smaller than that for the first time. 5. The unevenness of the surface of the press machine after the second time is
It is 0.1 mm or less, The manufacturing method of the electrode plate for retainer type sealed lead acid batteries of Claim 1 or Claim 2 or Claim 3 characterized by the above-mentioned.