JPS58220359A - Manufacture of plate for battery - Google Patents

Abstract

PURPOSE:To simplify the manufacturing process and shorten the manufacturing time of a plate for a battery, and realize a homogeneous high-density packing of an active material powder by introducing a base plate made of a foamy porous metallic body into a packing container which is packed with the active material powder, then giving vibrations to the base body so as to enable a sufficient amount of the active material powder to be packed into the holes of the base plate. CONSTITUTION:A base plate 1 is made of a foamy porous nickel body having a thickness of 1.8mm., a porosity of 96% and continuous holes with diameters of 100-500mu. The symbol 2 represents a packing container, which is packed with a mixture powder 3 consisting of 95 parts nickel hydroxide powder passed through a sieve of 200 mesh and 5 parts cobalt metal powder. A vibrator 4 installed at the bottom of the container 2 gives vibrations of 100Hz frequency and 1mm. amplitude for 30sec, to the base plate 1 which is positioned in the container 2. The volume of water 6 sprayed by a sprayer 6, should be 20vol% of the apparent volume of powder packed in the base plate 1. The particles of the packed powder are bound together by means of a polyethylene powder spreader 12 and a hot pressser 13.

Description

[Detailed description of the invention] ,Technical field The present invention relates to a method of manufacturing an electrode plate for a battery.

Background Art For example, nickel anode plates used in alkaline storage batteries are mainly produced by a sintering method. This method is known to have excellent mechanical strength, as well as excellent performance in terms of high rate discharge characteristics and cycle life, but the problem is that the manufacturing process is complicated and it takes a long time. There is.

As a manufacturing method that solves these manufacturing problems, there is a known method of applying and drying an active material paste to the core of an electrode plate such as a punched plate, but in terms of performance, sintered electrode plates are not suitable. However, in recent years, a manufacturing method has been proposed in which a foam-like porous metal body having three-dimensionally continuous pores is used as a substrate and an active material is held on this substrate. According to this report, it has been confirmed that the manufacturing process is simple, the manufacturing time is short, and the performance is equivalent to or in some cases superior to that of sintered electrode plates.

A specific example of this manufacturing method is explained using the case of a nickel anode plate as an example. A paste liquid is added to a mixed powder of nickel hydroxide powder and conductive agent powder to form a paste. By sliding it into the hole using a selective mechanical method, or introducing it by ultrasonic vibration or Machi degassing,
After drying, pressure is applied to form the completed electrode plate, or after pressurization, the substrate surface is impregnated with a suspension of polytetrafluoroethylene to prevent the active material from falling off, and then dried to form the completed electrode plate. . Although this manufacturing method is simpler than the conventional sintering method, it cannot be said to be a fully streamlined manufacturing method, and the process of filling the base-like active material into the pores of the substrate is difficult. However, it is difficult to pack evenly and densely.

DISCLOSURE OF THE INVENTION The present invention was invented in view of the above points, and is a method for manufacturing an electrode plate using a foam-like porous metal body having three-dimensionally continuous pores as a substrate. After filling the pores of a substrate made of a foam metal porous body with three-dimensionally continuous pores with active material powder while applying vibration, a liquid is added to prevent the active material powder from falling off. It is characterized by the following.

As a result of numerous experimental studies, the present inventor introduced a substrate made of a foam-like metal porous body into a filling tank filled with active material powder, and by applying vibration, It was confirmed that 11'1. can be filled into the holes of the substrate. Table 1 shows the results of investigating the effect of varying the vibration frequency, amplitude, and vibration time on the light filling during filling. 94%, and the filling amount is the light of nickel hydroxide powder (XP-average particle size 10μ or less) per 9-hole volume of the substrate:
! Jl lid shown. Moreover, the vibration time was all set to 1 minute.

Incidentally, when vibration is applied, the acceleration G that the substance receives is defined by the relationship between the half amplitude (u→a and the frequency (H2) f) as shown in the following equation.

G=41af! X 10-' Here, 4π2 is a constant, so the acceleration is proportional to the product of the amplitude and the square of the frequency.

As is clear from Table 1, the frequency is 100 Hz or more, the amplitude is 0.5 mm or more for 100 H2, 0°08 mIn or more for 200 Hz, and 0.0'hxm or more for 4DDH2, that is, the af2 value is 1600 or more. It can be seen that a high-quality Koei plate can be obtained.

Furthermore, all the values shown in Table 1 are for the case where vibration is applied only in the thickness direction, but even more efficient filling was achieved when vibration was added in the direction parallel to the substrate. However, in the case of vibration only in the parallel direction, the filling amount is 20% compared to the vibration only in the thickness direction.
It was around 60.

The substrate filled with the active material powder in this manner is taken out from the filling tank, and a liquid from which excess active material powder adhering to the substrate surface has been removed is added to the substrate surface to prevent the active material powder from falling off. The liquid may be added by spraying it in the form of a mist or by coating it. Furthermore, the type of liquid used is one that does not cause deterioration of the substrate and active material powder, such as water or alcohol. The amount of liquid added is 5-5% relative to the apparent volume of the active material powder filled in the substrate.
40 love, preferably Fi 8-60 excellent.

After that, the electrode plate is prepared by removing liquid by drying or pressing as necessary, compressing it under pressure, and then adding a binder to the surface of the substrate to complete the electrode plate. In this way, the manufacturing method according to the present invention Compared to conventional manufacturing methods, the manufacturing process can be simplified and the manufacturing time can be shortened, and the active material powder can be filled with high density and uniformity.

EXAMPLE 9 An example of the present invention will be described based on the manufacturing process diagram shown in FIG. 1, taking the case of a nickel anode plate for an alkaline storage battery as an example. (1) is a substrate, which is made of a foam-like porous nickel material having continuous pores with a pore diameter of 100 μm and a thickness of 1.8 μm and a porosity of 96%. (2) is a filling tank;
A mixed powder (3) consisting of 95 parts of nickel hydroxide powder and 5 parts of metallic cobalt powder passed through a 200 mesh sieve is filled. (4) is a vibrator placed at the bottom of the filling tank (2), and the substrate (1) located in the filling tank (2).
To this, vibration with a frequency of 100 Hz and a width of 1 mm is applied for 30 seconds. (5) is a sprayer that sprays water (6) in the form of a mist, and the spray amount is 20% by volume of the apparent volume of the powder filled in the substrate (1). (7) Port α Port O is a pressure roller that presses and compresses the substrate (1).

(1111ull is a resin sheet winding roller.a
21 is a polyethylene powder scatterer, and 131 is a hot press, which binds the particles of the filling powder together. The circle is the plate winding roller. The packing density of the active material in the completed electrode plate wound around this roller circle is 2.1 to 2,294.
It is p.

In order to compare this completed electrode plate with the conventional sintered type,
Cut into a rectangle of 50 x 30 mi, use the same cadmium electrode as the counter electrode, and discharge in a caustic potash solution with a discharge current of '/ioo%.
: Pond capacity was measured. Figure 2 shows its discharge characteristics, and the battery characteristics (A) according to the present invention are those of the sintered type battery (BI
The capacity is approximately 10q6 larger than K. Also, in terms of volumetric energy density, the sintered battery has a volumetric energy density of 420mAH7°. For a 7' stone, the battery to which the present invention is applied has a capacity of 46 mAIH/.

. , and the daytime energy density is obtained.

Next, the inventor studied the position of the substrate (1) in the filling tank (2) and found that it is better to place the substrate (1) at a position sufficiently far from the bottom of the filling tank (2) to increase the amount of powder to be filled. Table 2 shows the experimental results of the distance Ω- from the bottom of the cypress tree and the filling it (f;'/cc), which was found to increase ○light*. Only nickel hydroxide powder (200 mesh passes) was used as the filling powder, and the vibration conditions were a frequency of 100 Hz,
The vibration width was 1 angle, the vibration time was 6 o seconds, and the distance between the substrate surface and the top surface of the active material powder in the filling tank was 20 m or more.

Table 2: As the distance increases, the amount of filling increases.
Above wtn, the filling amount is almost the same.

In addition, when a polyethylene sheet was attached to the bottom surface of the substrate and buried in a filling tank, and vibration was applied under the same vibration conditions as above at a position several tirms or more away from the bottom surface, the filling amount was 0.2 to 0.3 y. /cc, which was extremely small.

From this, it is considered that if there is something in close contact with the lower surface of the substrate (1), the flow of the active material powder due to imaging, that is, the flow from dense to sparse, is obstructed and the filling l does not increase. Therefore, in order to increase/stop the filling efficiency, it is necessary to maintain a distance between the substrate and the bottom of the filling tank to the extent that it does not interfere with the flow of the active material powder toward the substrate. 485 parts, cobalt hydroxide powder 5 parts, ninkel powder 1
Using 0 part, hole 61i: about '500μ, hole 96 thickness 2. A case where a substrate made of Owtrr foam-like porous nickel material is used, and the distance between the substrate and the bottom of the filling tank is 10 degrees (Case 1) and 1 distance (Case 2).
Table 6 shows the experimental results of the filling time, filling amount, and variation in the filling amount in the case where the mixed powder is made into a paste and is rubbed onto the substrate (Case 6). In case 6, the above-mentioned mixed powder was used, and a 2% aqueous solution of carboxymethylcellulose was added to it at 60% by weight to make it into a paste.
The substrate is filled by being rubbed with a spatula-like rubbing tool.

In addition, Table 6 *There is variation lj'''C in the warehouse, so the number of samples was 100.

It is appropriate for the active material filling of the completed electrode plate to be 1.8 to 2.5 y/co, and if the thickness is adjusted by pressing after filling to 1/2 to 1/6 of the initial substrate, the filling The filling amount after if should be 0.8y/ac or more. As is clear from Table 3, Case 1 satisfies this filling amount,
1) There is little variation in the filling amount, and the filling time is less than 1/6 of the paste type (relative to the paste type 6).
;JEK has been shrunk.

Application 4 Da 1 In the embodiment described above, if the liquid added to the substrate that has passed through the optical fiber can easily penetrate into the pores of the substrate, a binder solution can be used. (For example, a polytetrafluoroethylene dispersion (8% solution) is used in an amount of 30% by volume based on the apparent volume of the filling powder).

1. The manufacturing method according to the present invention is not limited to the nickel anode plate shown in the example, but can also be applied to a cadmium cathode plate, and can also be applied to a substrate made of a foam-like metal porous body as a current collector and an active material support. When used as a body, it can also be applied to electrode plates of other types of batteries.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an example of the manufacturing process using the manufacturing method according to the present invention, and FIG. 2 is a diagram showing the discharge characteristics of the battery. (1)...Substrate, (2)...Filling tank, (3)...
Mixed powder, (4)...vibrator, (5)...liquid sprayer. Figure 2: Electric time (Hr)

Claims (1)

[Claims] (1) After filling the pores of a substrate made of a foam metal porous body with three-dimensionally continuous pores with active material powder while applying vibration, a liquid is added to prevent the active material powder from falling off. A method for manufacturing a battery electrode plate, characterized in that: