JPH0521055A - Manufacture of battery plate - Google Patents

Abstract

PURPOSE:To enhance the productivity in a group winding process by rolling a plate such that a positive electrode mixture, made of a battery active substance, a conductive agent, and a binder, being impregnated in a collecting body to a plate with no thickness distribution. CONSTITUTION:A sheet-like plate, such that a positive electrode mixture 1 being charged in a collecting body 2, is rolled, first, as a first process, with rolling mills No.1 through No.4 having roll diameters of 500 to 2000 times the plate thickness so as to increase the charge density. Next, as a second process, it is precisely rolled to a predetermined thickness by a rolling mill No.5 having a roll diameter of 100 to 300 times the plate thickness. By means of this manufacture, the variation of the charge density of the plate as well as of its thickness are decreased, so that productivity in a group winding process is increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a battery electrode plate in which a current collector is filled with a positive electrode mixture and pressed to form a paste electrode plate having a constant thickness.

[0002]

2. Description of the Related Art Conventionally, in a method of manufacturing a battery electrode plate of this type, a sheet-shaped electrode plate is passed between two rolling rolls as shown in FIG. 2 to perform rolling. The sheet-shaped electrode plate formed by filling the current collector 1 with the positive electrode mixture 2 including the battery active material, the conductive agent and the binder is pressed by the rolling rollers A and B to increase the packing density and roll the sheet. I was going. By repeating this rolling several times with several machines, the packing density and thickness were adjusted to a certain level.

As a battery electrode plate, the battery characteristics, particularly the discharge characteristics, are determined by filling a larger amount of the positive electrode mixture per unit volume. Therefore, the packing density of the positive electrode mixture has been increased by using a large-diameter rolling roll. As described above, the rolling roll having a large diameter is suitable for increasing the packing density, but is unsuitable for processing with a small thickness.

[0004]

In such a conventional structure, the packing density can be increased because rolling is performed by several rolling mills having a large diameter, but the current collector 1 and the positive electrode mixture 2 In the process of filling the
The weight varies. Therefore, it was very difficult to adjust the rolled electrode plate to a predetermined thickness. Further, in the process of spirally processing the positive electrode plate cut into a predetermined width via the negative electrode plate and the separator, the electrode plate having a large thickness distribution is one of the causes of process defects.

The present invention solves such a problem and manufactures a battery electrode plate which can be adjusted to a predetermined thickness in a rolling process and can supply a positive electrode plate of stable quality to the next step. It is intended to provide the law.

[0006]

In order to solve this problem, according to the present invention, a sheet-like electrode plate in which a current collector is filled with a positive electrode mixture is first prepared by using several large-diameter rolling rolls in the first step. After gradually increasing the packing density, the second step is a two-step step in which the thickness can be adjusted to a predetermined value with a small-diameter rolling roll.

[0007]

With this configuration, the positive electrode mixture filled in the current collector can have a sufficiently high packing density and can be accurately adjusted to a predetermined thickness.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to the drawings.
Explain. FIG. 1 shows the configuration of the rolling apparatus used in this example.
Show. Processed into lath metal or punching metal
The active material for the battery, the conductive agent and the binder
First, a sheet-like electrode plate filled with the positive electrode mixture 2 made of
φ400mm rolling roll A₁~ A_Four, B₁~ B_FourHaving pressure
Increase the packing density with four lathes (No1 to No4), then φ5
0 mm rolling roll A ₆, B₆And an auxiliary law thicker than that
Le A_Five, B_FiveWith one rolling machine (No. 5) having
Adjust to 0.4mm. In addition, each rolling
The initial setting of the machine roller gap is 0.1mm
Set it.

In the above state, 30 lots of electrode plates each having a length of 300 m and a width of 25 mm were rolled, and variations in electrode plate thickness were measured. Also, manganese dioxide lithium battery CR-
2/3 A (Height 35 mm, Diameter 17.5 mm, Electric capacity 130
In the so-called group winding process, in which the electrode plate for 0 mAh) was cut into a predetermined size and processed into a spiral shape through the negative electrode plate and the separator, the occurrence ratio of process defects due to thickness variation of the electrode plate was examined.

Table 1 shows the variation in thickness of the electrode plate and the process defect rate due to the electrode plate in the group winding process in comparison with the product of the present invention and the conventional example. In this case, the number of samples is 100 each.
It compared with 0 pieces.

In the present embodiment, the large diameter rolling roll diameter was set to 1000 times the electrode plate thickness of 400 mm, and the small diameter rolling roll diameter was set to 125 times the electrode plate thickness of 50 mm. As a result of further detailed examination, The diameter of the large diameter rolling roll is 500
~ 2000 times, the diameter of the small diameter rolling roll is 100 of the electrode plate thickness
Similar results were obtained in the range of up to 300 times.

[0012]

[Table 1]

As described above, according to the manufacturing method of this embodiment, an electrode plate having no variation in lots and lot-to-lot variations can be obtained, and even in the group winding process, the thickness is made uniform, and a great improvement in process defects is recognized. Was given.

[0014]

As is apparent from the above description of the embodiments, according to the present invention, it is possible to adjust an electrode plate having a large thickness variation within / between lots to a plate having a uniform thickness. It is possible to supply a battery electrode plate with stable quality.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a rolling process according to an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a conventional rolling process.

[Explanation of symbols]

1 Current collector 2 Positive electrode mixture A ₁ , A ₂ , A ₃ , A ₄ Upper rolling roller B ₁ , B ₂ , B ₃ , B ₄ Lower rolling roller A ₅ Upper auxiliary roller A ₆ Upper thickness adjusting roller B ₅ Lower mill No5 rolling mill having a small diameter rolling roll having an auxiliary roller B ₆ under thickness control roller No1~No4 large径圧rolling rolls

Claims (2)

[Claims] 1. A positive electrode plate is prepared by filling a positive electrode mixture mainly composed of a battery active material, a conductive agent and a binder into a conductive current collector processed into a lath metal shape or a punching metal shape to prepare an electrode plate. In the first step using a large-diameter rolling roll to increase the packing density, and in the second step using a small-diameter rolling roll to form a predetermined thickness for a battery electrode plate. 2. The battery according to claim 1, wherein rolling is performed with a large diameter rolling roll having a roll diameter of 500 to 2000 times the electrode plate thickness and a small diameter rolling roll having a roll diameter of 100 to 300 times the electrode plate thickness. Manufacturing method of electrode plate.