JPS5945183B2 - Manufacturing method for paste electrodes for lead-acid batteries - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION There are two types of electrode plates that have been widely put into practical use as plates for lead and drip ponds: base, base, and clad types.

The lathe-paste type electrode plate of Nikira's electrode plate is made by adding dilute sulfuric acid to a lead compound and making it into a paste, and applying it in one line to a support such as a lattice, a perforated plate, an expanded plate, or a barrel. Since it is manufactured using a drying method, the process is simple and the discharge characteristics are not bad, but when relatively deep charging and discharging are repeated, the active material softens and falls off, which limits the charge-discharge cycle life. That is the problem. On the other hand, clad-type electrode plates are manufactured by filling a cylindrical container made of acid-resistant resin or glass fiber with an active material together with a current collector, and although the manufacturing process is somewhat complicated, Due to its robust structure, it has a longer lifespan than paste-type electrode plates. The present invention improves a paste-type electrode plate to provide a method for manufacturing a lead-acid battery electrode plate that has an improved Q-cycle life after repeated charging and discharging without causing deterioration in discharge characteristics.

1 Conventional methods for extending the cycle life of lead-acid batteries that use paste-type plates include, for example, holding the plate group in a battery case under a certain pressure, or Methods such as wrapping the anode plate in a porous separator have been adopted, but this is still not sufficient.

In addition, thermoplastic resin powder is applied to the surface of the paste/end mouth Q.
By heating the resin to a temperature above the melting point of the resin, a microporous layer of the resin is directly formed in the kneading layer.
□Bees, how to suppress the shedding of active materials, nutrition,
After forming a porous layer, the inside of the electrode plate is further coated to form a disk barge containing thermoplastic resin!冫゛、←く■
The thermoplastic resin contained in the air is impregnated with 1 kg drying agent, and the thermoplastic resin contained in the air ion is heated to an almost numbing temperature. The present inventors have already proposed a method for improving this.

The present invention aims to improve these methods, and the main points thereof are as follows.

First of all, it can be in any state: unformed electrode plate, I chemically formed electrode plate, or mercy electrode plate, but Dispurge which contains acid-resistant resin in the paste type electrode plate! When the surface of the electrode plate is wetted with the dispersion, a thermoplastic resin powder is applied to the surface of the electrode plate. Next, the electrode plate
is heated to a temperature at which the thermoplastic resin powder attached to its surface melts. Here, the acid-resistant resin contained in the dispersion or emulsion may be a thermoplastic resin such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, or a derivative thereof, or may be a thermoplastic resin such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, or a derivative thereof. It is also possible to use a non-thermoplastic resin such as ethylene chloride, but it is necessary to use fine particles, for example, about 20 μm or less, that can become a dispersoid in a dispersion or emulsion.

In addition, the thermoplastic resin to be attached to the surface of the electrode plate is a resin that has a melting point lower than the temperature at which the lead alloy or lead compound that forms the electrode plate changes, and is highly acid resistant and oxidation resistant, such as polyethylene, polypropylene, Polystyrene, polyvinyl chloride, etc. can be used alone or in combination, and the particle size of the resin powder varies depending on the condition of the electrode plate surface, but is approximately 1.
Approximately 5 to 200μ is good. Note that the resin contained in the dispersion or emulsion will naturally penetrate into the pores inside the electrode plate if the dispersion or emulsion is impregnated into the electrode plate. The resin powder attached to the surface of the electrode plate in a damp state hardly penetrates into the pores inside the electrode plate, and is concentrated near the apparent surface of the electrode plate.

Therefore, according to the present invention, the inside and surface of the electrode can be reinforced after the paste has been applied or after the electrode has been chemically formed. Examples of the present invention will be described below.

An unformed paste-type positive electrode having a width of 48 wrfL and a height of 74'' and a thickness of 1.5 tfr1n is impregnated with an emulsion (resin content: 3% by weight) containing 5 polyethylene powder as a dispersoid with a particle size of about 5μ and a melting point of 110°C.

Next, in a subdued state with the surface of the electrode plate moistened with water, which is the dispersion medium of the emulsion, polyethylene powder with a particle size of about 100 μm and a melting point of about 120°C was added to 4 mg/D per apparent unit surface area.
5 and heat at 140-150°C for 20 minutes.
The electrode thus obtained is designated as A. Further, as a comparative example, the electrode shown below was obtained.

First, impregnation with emulsion or dispersion,
4. Those without any treatment such as adhesion of resin powder are designated as B.

Also, in A, only water is used instead of emulsion,
C is a plate in which polyethylene powder is attached to the surface of the plate and heat treated. D is obtained by impregnating the emulsion used in A and then heating at 140 to 150°C for 20 minutes. The three positive electrodes mentioned above and the four paste-type negative electrodes have a thickness of approximately 0.8m between them! Glass fiber mats and pulp separators with a thickness of about 0.6Tvn are alternately stacked on top of each other with the latter separator in contact with the negative electrode to form a single cell, and six single cells are made into a module for 10 hours. A block battery with a discharge capacity of about 4.5 Ah was constructed.

Batteries using positive electrodes A to D are designated as ad, respectively. These batteries were discharged at 30°C for 1.5 hours at a current of 1.8A and charged for 4.5 hours at a current of 0.72A using sulfuric acid as an electrolyte with a specific gravity of 1.28 at the end of charging. The figure shows the change in terminal voltage at the end of discharge when charging and discharging are repeated.

As is clear from the figure, C and D exhibit improved cycle characteristics compared to B, which does not undergo any treatment on the electrode plate, but A has better cycle characteristics than any of these comparative examples B-D. It can be seen that this shows that

Among these, A? :． D is based on the process of impregnating the electrode plate with emulsion and then adhering resin powder to the electrode plate surface, or the process of forming a porous layer of resin on the electrode plate surface and then impregnating it with emulsion. The only difference is that However, in the former case, compared to the latter case, the emulsion penetrates evenly into the pores inside the electrode plate, so a three-dimensional network structure of the resin is formed inside the electrode plate, and it is also formed on the surface of the electrode plate. It is considered that the synergistic effect of the porous layer made of the resin effectively suppresses the softening and falling off of the positive electrode plate active material that occurs as the cycle progresses, resulting in good cycle characteristics. In addition, although the example of application to a positive electrode plate was shown in the embodiment, if the present invention is applied to a negative electrode plate, the effect of extending the life of the negative electrode plate can be obtained.

[Brief explanation of drawings]

The drawings show changes in terminal voltage during charging and discharging of lead-acid batteries using various positive electrodes.

Claims (1)

[Claims] 1 After impregnating a paste-type electrode with a dispersion or emulsion containing an acid-resistant resin, an acid-resistant thermoplastic resin powder is attached to the surface of the electrode that has been moistened by the above treatment, and the thermoplastic resin is A method for manufacturing a paste-type electrode for lead-acid batteries, which is characterized by heating to a melting temperature.