JPS59191263A - Manufacture of cell plate - Google Patents

Abstract

PURPOSE:In a method for filling a porous metal sponge with active substance powder, to eliminate fluctuation of plate performance by limiting the grain size of active substance powder and apparent density under dry state thereby increasing the filling amount of active substance and preventing deterioration of initial plate capacity. CONSTITUTION:When employing porous metal having frame structure continuous in three-dimension such as porous nickel sponge as the basic body then impregnating with liquid and immersing the active substance powder thereafter placing porous metal in an active substance powder bed and applying vibration to perform filling, the apparent density of active substance under dry state is made 0.9g/cm<3>, preferably higher than 1.0g/cm<3>, while the grain size of active substance is made below 1/40-1/50 of basic member hole diameter to achieve high filling efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial Application Field The present invention is directed to a battery which uses a porous metal material having a three-dimensionally continuous skeleton structure as a substrate and fills the substrate with active material in powder form. The present invention relates to a method of manufacturing an electrode plate.

(b) Prior art electrode plates for batteries, especially electrode plates for Al-h IJ storage batteries,
Traditionally, sintered electrode plates have been mainly used.For example, in the case of nickel anode plates, the porous structure is obtained by applying a slurry containing Ni-Nkel powder to the electrode plate core and then sintering it. It is manufactured by impregnating a substrate with a di-norm salt solution and then substituting the hydroxide with an alkali. This left-making method has the advantage of long-lasting electrode plates that have excellent mechanical strength, high-rate discharge characteristics, and cycle life, but on the other hand, the manufacturing process is complicated and takes a long time to manufacture. There is a problem that the manufacturing cost is high (1/).

As a manufacturing method that solves these manufacturing problems, a method is known in which a molten paste is applied to the core of an electrode plate such as a punched plate and then dried, but in terms of electrode plate performance, sintered electrode plates are (Compared to this, C is several steps inferior.

In recent years, porous metal bodies (hereinafter referred to as sponge-like porous metal bodies) having a three-dimensional fence-like skeleton structure have been used as substrates.
A manufacturing method has been proposed in which this is filled with an active material. This sponge-like metal porous material has a porosity of approximately 95%, which is approximately 80% higher than that of the sintered substrate, so the amount of active material filled increases compared to the sintered substrate, resulting in high capacity. It is possible to manufacture electrode plates, and since the pore diameter is 300 to 700μ, which is about 100 times larger than that of sintered substrates, it is possible to manufacture electrode plates without dissolving the active material.
This can be filled directly. Furthermore, since the conductive matrix of this substrate is fixed, there is an advantage that there is no need to add various conductive agents as in the case of a paste type.

As described above, an electrode plate using a sponge-like porous metal material as a substrate has excellent characteristics, and the manufacturing method is to add a glue liquid to a mixed powder of active material powder and conductive agent powder to form a paste. A method of sliding active material powder into a sponge-like porous metal body, or a method of filling a sponge-like porous metal body with active material powder by vibration and blowing has been proposed. However, although the former manufacturing method is simplified compared to the sintering method, it cannot be said to be a fully rationalized manufacturing method, and the paste-like active material is uniformly and densely packed within the pores of the substrate. In order to solve this problem, a method is disclosed in Japanese Patent Publication No. 55-39109 and Japanese Patent Publication No. 55-39109, in which a sponge-like metal porous material is impregnated with a liquid and a paste-like active material is rubbed into the pores of the substrate. Although disclosed in Publication No. 56-'r7664, in this method as well, since the paste mixes with the liquid in the pores, the degree of active material and the fluidity of the paste change over time, and the filling amount Since it is difficult to adjust the amount of paste and the liquid content of the paste increases, there is a problem that the amount of filling is small.

In the latter case, the active material can be easily and uniformly filled into the sponge-like porous metal material without using a thickener, and a high utilization rate and volumetric efficiency can be obtained. but,
As we proceeded with the actual M study, we found that due to the difference in the particle size of the active material, there would be variations in the amount of active material being filled, leading to problems such as insufficient filling amount and low initial capacity of the electrode plate. It was found that this occurs.

(c) Purpose of the Invention In view of the above, the present invention provides a filling method in which a sponge-like porous metal body is directly filled with a powdered active material. The purpose of this is to increase the filling amount of active material, prevent a decrease in the initial capacity of the electrode plate, and eliminate variations in the performance of the electrode plate.

B) Structure of the Invention The present invention provides a filling method in which a porous metal body having a three-dimensionally continuous skeleton structure is used as a base, and the porous body is impregnated with a liquid, and then active material powder is precipitated in the liquid; and a method of filling the metal porous body by placing the metal porous body in an active material powder bed and applying vibration. In the method of manufacturing storm pole plates for ponds,
The particle diameter of the active material is set to 1/4 of the average pore diameter of the porous body (
14, and the apparent density in the dry state at the time of filling is 0.9.
y/ce9J.

(e) Examples Experiments and examples related to the present invention are shown and explained below.

〔experiment〕

As an electrode substrate, the average pore diameter is about 300μ and about 500μ (
The base manufacturers are 7 Q Ce1l/1nch and 45 respectively.
Using two types of sponge-like porous nickel materials, each having a thickness of 2 mm, the pulverization degree of the active material was changed to make the particle size uniform. A C substrate was filled with an active material using nickel hydroxide, and the particle size of the active material, the amount filled into the sponge-like porous nickel body, and the apparent dry state and density of the active material were measured. The powder particle size of the active material is measured using a Finscher subsieve sizer (hereinafter this measured value is referred to as the Fischer size), and the filling method is to completely fill the pores by immersing a sponge-like porous nickel material in water. After displacing the water with water, the porous body was taken out of the water and left to stand horizontally, and nickel hydroxide powder was dropped little by little from above °C to fill the sponge-like nickel with nickel hydroxide. A method was used in which the filling operation was stopped when the holes were completely filled with nickel hydroxide. The results are shown in Table 1.

As can be seen from Table 1, when a sponge-like porous nickel material with an average pore diameter of approximately 300μ is used, the Fisher size is 6.0μ.
When filled with active material powder of tata 1μ or less, or when sponge-like nickel with an average pore diameter of about 500μ is filled, the size is Y-size 3. Fill the active material powder with an OP wicking capacity of 8.3μ or less to obtain the maximum filling amount at one time. In both cases, the particle size of the active material is about 1/40 to 1,760 or less of the average pore size of the sponge-like porous nickel material, and a crystal-filled filtrate is obtained on the Fisher size or 2.2μ of the trading company active material. By the way, they have C in common. The reason for this is thought to be as follows. The sponge-like nickel porous material used had pores with average pore diameters of 300P and 500μ, respectively.When this substrate was closely observed, it was found that pores with a diameter of 1/6 or less of the average pore diameter were used. It turns out that it exists. Furthermore, when the active material powder used in the experiment is further passed through a 325-mesh sieve, 0.5 to 20% of the active material remains on the crystal depending on the degree of pulverization, and the active material powder contains large particles (a
It was found that particles of 10 IL) exist. Therefore, the ratio between the minimum pore size of the substrate and the maximum particle size of the active material is actually 2.
:1-3:1, Fisher size 10.6-6
．． For an active material with a relatively large particle size of 1μ, the ratio of the minimum pore size of the substrate to the maximum particle size of the active material becomes small, and accordingly, the proportion of large particles becomes large (as a result, they block the pores of the substrate). In addition, the powder has a large proportion of large particles even though the size ratio between the minimum pore size of the substrate and the maximum particle size of the active material is 2:1 to 3:1. The reason for the poor filling properties of the body is presumed to be as follows.In the method of turning powder into a paste and press-fitting it into sponge-like nickel using a jig such as a rubbing tool, particles are formed in the circular part of the base. Even if the particle hits the network skeleton of the substrate and is blocked, there is a glue around the particle that helps it slide, and an external force is applied to it, allowing it to move further into the substrate.In contrast, in the experiment described above, When a filling method that utilizes the particle's own weight is adopted, if the movement of the particle is blocked by the network skeleton inside the substrate, the particle will come to a complete standstill. If so, it will reduce the opening area of the pores in the substrate and stop the movement of particles that enter later, and powders with a high proportion of large-sized particles will have a small filling amount.Next, the Fischer size The reason why the filling amount decreased when using active material powder with a particle diameter of less than 2.2μ is that as the Fischer size decreases,
It is thought that the appearance of active VJ quality is due to a decrease in density2, and it is assumed that this is due to the unevenness and shape of the particle surface of the active material.

Therefore, even if the active material powder efficiently fills the pores in the substrate, the amount of active material packed is considered to have substantially decreased.Also, the apparent density decreases as the Fischer size decreases. However, the reason why the filling amount of active material powder above Fischer size 3 μu is high is that the filling rate of the pores in the substrate is the same due to the smaller diameter of the active material particles, but the apparent density of the active material powder is reduced. Therefore, considering the workability when filling the active material and the performance when it is made into a completed electrode plate, the apparent dry state of the active material during filling is due to the density. It can be seen that high filling efficiency can be obtained when the particle size of the active material is 1/40 to 11501a below the substrate pore diameter.

Next, Teflon dispersion was added to the substrate filled with the active material according to the above experiment and dried to fix the active material within the substrate, and further pressurized at a pressure of 300 Ky/cd to obtain a completed electrode plate. This electrode plate was combined with a cadmium electrode plate in a caustic alkaline electrolyte and charged and discharged, and the utilization rate of the active material and high rate discharge characteristics were measured. In addition, the discharge is 4C only during high rate discharge.
The discharge was carried out at 0.10 in the other cases, and the high rate discharge characteristic is the ratio when the 0.1C discharge capacity at the 10th cycle is taken as 100%. The results are shown in Table 2.

As is clear from Table 2, Fisher size is 6゜1μa.
The initial utilization rate of the electrode plate filled with the above active material is low. However, by repeating charging and discharging, the utilization rate reaches the III+ level regardless of the Fischer size of the active material.
The difference in utilization rate will be eliminated. Also, the average pore size of the substrate's sponge-like nickel is approximately 100%. As the temperature increases, Shoji discharge performance decreases.

In the experiment, C showed tests on two types of substrates with different pore sizes, but if a substrate with a small average pore size was used, it was necessary to use a substrate with a small average particle size. If a substrate with an average pore diameter that requires an active material with an apparent density of less than 0.9 y/arl is used, a sufficient amount of active material cannot be obtained.

It may also be possible to try to homogenize the pore size of the substrate, or the current manufacturing method of sponge-like metal porous bodies made of polyurethane foam. In addition, with respect to a substrate using a mat-like porous material of fibers as a starting material, similar results were obtained with C, and it was difficult to homogenize the pore diameter of the substrate.

Next, examples will be shown and explained below.

[Example 1] A sponge-like porous nickel material (thickness: 1.5 mm) with an average pore diameter of about 300 μm was used as a substrate, immersed in a 4% Teflon dispersion solution, and taken out while retaining the solution on the substrate. Stand it horizontally and add nickel hydroxide 85i1%, nickel) Lt powder (INC) with a Fischer size of 4.4μ.
Made by Company O, +255) 10ffilt%, 5% by weight of cobalt hydroxide with a Fischer size of 3μ is mixed and filled into the substrate by dropping it little by little from above, and after filling is completed, it is dried and the pressure is set to 6001. Pressure was applied to form a completed electrode plate.

[Example 2] In Example 1, an electrode plate was prepared using a sponge-like porous nickel material with an average pore diameter of about 500 μm as the substrate, and under the same conditions as above.

[Comparative Example 1] In Example 1, an electrode plate was prepared using hydrated nickel having a Fisher size of io and 6 μm, and other conditions were the same.

[Comparative Example 2] An electrode plate was prepared under the same conditions as in Example 1 except that C1 nickel hydroxide having a Fischer size of 1.7 μm was used.

The amount of filling per unit volume of pores in the electrode plates prepared in the Examples and Comparative Examples was measured, and then the electrode plates of the Examples and Comparative Examples were used to construct a nickel-cadmium battery, and the performance of the battery was evaluated. It was measured. These results were compared to batteries A, B, and B using the electrode plates of Example 1, Example 2, Comparative Example 1, and Comparative Example 2, respectively.
Shown as C and D in Table 3 and Ward. In addition, the high rate discharge characteristics in Figure 6 are 40 when 0.10 discharge 8M is taken as 100%.
This is the discharge valley amount, and the figure is a cycle characteristic diagram of the battery.

Table 3 From Table 3, the filling amount of active material is shown in Examples for batteries A and B.
It can be seen that the number of electrode plates has increased significantly compared to Batteries C and D, which are comparative examples, and Batteries A and B also have better utilization rates at the cut-off stage and at the third cycle of 0.1C discharge. It shows the value. Although this usage rate shows a value that is worse than the battery life,
Since the filling amount of active material is small, the capacity is smaller than that of batteries A and B. In addition, regarding high rate discharge characteristics, as mentioned above, battery B, which has a large pore diameter in the substrate, is slightly inferior to other batteries. Next, from the drawing, the cycle characteristics show that batteries A and B show a stable utilization rate at the beginning of charging and discharging and even after 300 cycles, whereas battery C has a low utilization rate at the beginning of the cycle (battery C shows a stable utilization rate after 200 cycles). When the value exceeded 1, the reduction in the utilization rate became large.Furthermore, the filling state of the active material in the electrode plates of batteries A and B was uneven (uniform).

Furthermore, by placing a sponge-like porous nickel material in a container containing dried active material powder and applying vibration, a similar experiment was attempted using a filling method in which the active material was filled into the sponge-like porous nickel material. Almost similar results were obtained. The present invention can be widely applied to electrode plates manufactured by C manufacturing using a filling method in which a porous metal body having a three-dimensional structure is directly filled with a powdered active material.

(f) Effects of the Invention The present invention produces a sponge-like mF porous material in powder form! In the filling method of directly filling the active material of S, the particle size of the active material is regulated to 1/4 degree or less of the average pore diameter of the sponge-like metal, and the apparent dry state of the active material is 0.9y/cyA
By regulating as described above, a high filling capacity can be obtained, a decrease in the initial volume j of the electrode plate becomes less than fA, and variations in the electrode plate performance are almost eliminated.

[Brief explanation of the drawing]

The figure is a Wj-cycle characteristic diagram of pond 7I.

Claims (1)

[Claims] (11) A porous metal body having a three-dimensionally continuous skeleton structure is used as a substrate, and the substrate is directly filled with a powdered active material or a powdered mixture mainly composed of the active material. In the method for manufacturing an electrode plate for a battery, the particle size of the active material is 1/40a or less of the average pore size of the metal porous body, and the apparent density of the dry state at the time of filling is 0.9ylcrRLJ or more. A method for manufacturing an electrode plate for a battery, characterized in that: +21 The filling method for the active material described in R is a filling method in which the porous metal body is impregnated with a liquid, and then the active material powder is precipitated in the liquid. A method for manufacturing an electrode plate for a battery according to claim 1. (3) The method for filling the active material includes filling the porous metal body by placing the porous metal body in an active material powder bed and applying vibration. A method for manufacturing a battery electrode plate according to claim 1, which is a method.