JP3298177B2 - Method for manufacturing electrode plate for lead-acid battery - Google Patents

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 an electrode plate for a lead storage battery.

[0002]

2. Description of the Related Art In general, an electrode plate for a lead storage battery is manufactured by filling a current collector with an active material paste obtained by kneading lead oxide with sulfuric acid and water, and then aging, drying, and forming the paste. The capacity and active material utilization of the lead storage battery can be increased by increasing the amount of electrolyte contained in the active material of the electrode plate. In particular, when the amount of the electrolytic solution contained in the anode active material is increased, the capacity of the battery at the time of high-rate discharge can be significantly increased. Therefore, it has been proposed to increase the thickness of the active material layer of the electrode plate or to form a porous active material layer using an active material paste having an increased sulfuric acid content.

[0003]

However, when the thickness of the active material layer of the electrode plate is increased by increasing the amount of the active material, there arises a problem that the weight of the battery increases. In addition, when an active material layer is formed using an active material paste having an increased content of sulfuric acid, the viscosity of the active material paste increases, so that it becomes difficult to fill the active material paste into the current collector and productivity decreases. ,
A problem arises that special equipment is required.

[0004] It is an object of the present invention to provide a method for producing a lead-acid battery electrode plate which can increase the porosity without increasing the amount of active material and which does not reduce the productivity.

[0005]

SUMMARY OF THE INVENTION The present invention is directed to a method of manufacturing an electrode plate for a lead-acid battery. In the invention of claim 1, fibers which decompose, burn or shrink during the manufacturing process of the electrode plate are added as an additive. The active material paste is used to form an active material layer.

According to the second aspect of the present invention, as the fiber in the first aspect of the present invention, a fiber which is soluble in an acid, a fiber which burns off when the electrode is dried, or a fiber which shrinks when the electrode is dried is used.

[0007] In the invention of claim 3, cellulose fibers are used as the fibers in the invention of claim 1.

[0008]

According to the present invention, the fibers added to the active material paste as an additive are decomposed, burned out or shrunk during the manufacturing process of the electrode plate, so that the additive material is contained in the active material layer of the completed electrode plate. Fine pores can be formed in portions where fibers are decomposed, burned out or shrunk. Further, since only the fibers are added, the viscosity of the active material paste does not substantially increase, the productivity does not decrease, and the production can be performed using existing equipment. For example, at the time of formation like cellulose fiber,
If fibers that oxidize, decompose, burn or shrink when the electrode plate is dried are used, relatively large pores can be easily formed in the active material layer. Further, according to the present invention, since relatively large pores can be formed in the active material layer, the electrolyte solution diffuses into the active material layer, and the charge and discharge can proceed almost uniformly over the entire electrode plate. The stress on the active material due to local reaction does not increase. Therefore, the active material can be prevented from falling off, and the life characteristics of the battery can be improved.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The manufacturing method of this embodiment will be described in detail below, taking as an example a method of manufacturing an anode plate for a lead storage battery. First, an active material paste was prepared by kneading lead dioxide, cellulose fiber of 0.5% by weight based on the lead dioxide, purified water and sulfuric acid. The amount of purified water was adjusted so that the active material paste had the same hardness or the same viscosity as the active material paste when no cellulose fiber was added. Next, this active material paste was filled in a current collector, and then the mixture was aged, dried and formed to complete an anode plate for a lead storage battery.

Next, in order to examine the characteristics of the anode plate manufactured by the method of this embodiment, two kinds of anode plates a and b were prepared and tested. The anode plate a is an anode plate manufactured by the method of the present embodiment, and the anode plate b is an anode plate manufactured by a conventional method without adding cellulose fibers to the active material paste. The anode plates a and b were manufactured in the same manner except that cellulose fibers were added. Then, each of the anode plates a and b is laminated with a known cathode plate which does not add cellulose fibers to the active material paste and a retainer impregnated with an electrolyte to form an electrode plate group. The lead storage batteries A and B were wrapped in a resin film. And 3 of each lead storage battery A, B
The battery capacity and the energy density per weight at 0 fraction were measured. Table 1 shows the measurement results.

[0011]

[Table 1] From this table, it can be seen that the use of the anode plate a manufactured by the method of this example can increase both the capacity and the energy density of the battery by 40% compared to the case of using the anode plate b manufactured by the conventional method.

Next, charging and discharging of the batteries A and B were repeated, and the cycle life characteristics of each battery were examined. FIG. 1 shows the measurement results. From this figure, it can be seen that the use of the anode plate a manufactured by the method of this embodiment can improve the battery life characteristics as compared with the case of using the anode plate b manufactured by the conventional method. This is because in the anode plate a, the electrolytic solution diffuses into the active material, and charging / discharging proceeds almost uniformly over the entire electrode plate.

In this embodiment, the present invention is applied to the case of manufacturing an anode plate, but it goes without saying that the present invention can be applied to a cathode plate.

In the above embodiment, cellulose fibers are used as fibers to be added.
Other fibers that burn or shrink may be used.

[0015]

According to the present invention, relatively large pores are formed in the active material because the fibers added to the active material paste as an additive are decomposed, burned out, or shrunk during the manufacturing process of the electrode plate. Can be. Therefore, the porosity of the electrode plate can be increased, and the capacity and active material utilization of the battery can be increased.

[Brief description of the drawings]

FIG. 1 is a diagram showing the life characteristics of a battery used in a test.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-59-23461 (JP, A) JP-A-5-343068 (JP, A) JP-A-5-109409 (JP, A) 54877 (JP, A) JP-A-4-368774 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01M 4/14-4/34 H01M 4/62

Claims (3)

(57) [Claims] 1. A method for manufacturing an electrode plate for a lead-acid battery, comprising forming an active material layer using an active material paste to which fibers which decompose, burn out, or shrink during an electrode plate manufacturing process are added. . 2. The electrode for a lead-acid battery according to claim 1, wherein the fiber is a fiber that is soluble in acid, a fiber that burns off when the electrode plate is dried, or a fiber that shrinks when the electrode plate is dried. Plate manufacturing method. 3. The method according to claim 1, wherein the fibers are cellulose fibers.