JPS60151966A - Non-sintered cadmium negative electrode - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to improvements in cadmium negative electrodes for use in alkaline city ponds, particularly for sealed nickel-cadmium city ponds.

Conventional configurations and their problems Currently, secondary batteries are used in many portable aircraft routes, mobile power sources, etc. From the practical situation, the older brother is the lead-acid battery and the nickel-cadmium E1, which have historically been popular.
%1111 l Yu accounts for the majority.

Among these, nickel-cadmium storage batteries come in pocket type and sintered type, as well as open type and sealed type. +9 is currently popular because it is a sealed sintered nickel-cadmium storage battery, which has excellent high-rate discharge and low-temperature discharge, as well as long service life and high performance stability.

The manufacturing methods for cadmium negative electrodes are broadly divided into sintered electrodes and non-sintered (baasted) electrodes. The former sintered electrode uses an aqueous solution of cadmium salt, fills the nickel sintered body with cadmium salt, dries it, and then immerses it in an alkaline solution. , decompose, convert to cadmium hydroxide, wash with water, and dry. This process is repeated several times to obtain an electrode plate. The main non-sintered type of the latter is a paste-type electrode, in which cadmium oxide powder or cadmium hydroxide powder is mixed with nickel powder and aborium powder to improve electrocardioactivity.
The mixture is kneaded with a solution containing B-adhesive resin to form a paste, which is then applied to a power-dissipating porous material.1.Then is dried to obtain an electrode plate.

Compared to the former, the latter does not require a nickel sintered body and the process of filling the active material is simpler.

Therefore, the manufacturing cost of electrodes can be significantly reduced, and the proportion of paste-type electrodes is increasing.

The strip-shaped electrically conductive porous material used as the three types of paste-type electrodes is mainly made of metal, such as punched metal made of nickel-plated iron, solid metal, and expanded metal. It's here. Among these, punched metal has become widely used because it has low manufacturing costs and is difficult to deform or break even when passed through a high-viscosity base.However, punched metal, net, and expanded band No matter which metal is used, the electron conductivity in the thickness direction is lower than that of a sintered 2' electrode in which the nickel sintered body is filled with 4'% of active material.

As a way to compensate for this, nickel powder is added into the paste.
It is conceivable to mix carbon powder or the like, but if it is added in multiple layers, the proportion of cadmium, which is an active material, will decrease. Furthermore, by reducing the porosity of the paste-type electrode plate by applying pressure, electronic conductivity and packing density can be improved. However, when the porosity is low, the utilization rate of the cadmium electrode decreases, and the absorption reaction of oxygen gas generated from the nickel positive electrode during overcharging also decreases.

As a result, not only does rapid charging become difficult, but even during slow charging, the internal pressure of the battery rises abnormally, and the generated gas escapes to the outside of the battery. Therefore, there is a limit to the addition of conductive powder to improve the electronic conductivity of the electrode plate or to lower the porosity of the entire electrode plate.

Purpose of the Invention The present invention aims to improve the usability and discharge potential of such a non-sintered cadmium negative electrode.
The purpose is to provide excellent release performance and also to improve gas absorption characteristics when used in a closed type.

Structure of the Invention The present invention uses the addition of nickel flakes having a scale structure to a mixture mainly composed of cadmium oxide or cadmium hydroxide powder, which has been conventionally used. By replacing all or part of the graphite or nickel powder with nickel flakes, the utilization rate of non-sintered cadmium negative electrodes can be improved, and this can also reduce the amount of oxygen in a sealed type, since it can also cause porosity. Gas absorption capacity can also be improved.

Nickel flakes are structurally different from regular powder,
It has a plate-like structure with a thickness of less than 1 micron and an average diameter of more than 20 microns, and during discharge, it is capable of acting as an excellent cardiogravity body compared to cadmium hydroxide, which has poor electrocardiographic properties. . Scaly black 3) has a similar structure and effect, but Ni-Nokel flake has excellent electrolyte resistance,
Since it is also excellent in terms of electrocardioactivity, it produces excellent results with respect to the potential of the cadmium negative electrode and the longevity of the a11. Of course, mixed use with nickel powder or graphite is also cost-effective.However, in the case of cadmium negative electrodes, the main reason is that conductive cadmium is formed during charging.
Additive 11-1 of barrel electric agent should be less than 20%.
Column description Iron plated with nickel, thickness o, 1mm, hole diameter 2m〃
l. A belt-shaped punched metal with a center-to-center pitch of 2.5n and a width of 280tn is used as the core and material, while the oxidizing power is 1 Beum 4, and the scale-like structure has a thickness of 0.8 microns and an average diameter of 25 microns. 30g/l ethylene glycol (fJl&; and his~4111) from Tiquin International Corporation with
Vinyl chloride-acrylonitrile copolymer fiber 2Tf cut into M size was sufficiently mixed to form a paste.

Apply this paste to both sides of the core and core L, 0.6pr
The paste was passed through slits spaced apart by y to remove excess paste, and heated at about 130'C. The thickness after drying was approximately 0.76ffll+, which was thicker than the slit width. This was pressurized using a spacer with a thickness of 0.6#Il#, and the thickness was made to be approximately 0.63ml.The thus obtained cadmium negative electrode was cut into a size of 36 gM in width and 280 MtN in thickness. Then, the lead plate was attached by welding through the slots. After that, the electrode 1 was placed in a caustic potassium aqueous solution with a specific gravity of 1.20.
Partial charging was performed so that 25mAh was charged per C77.

After that, it was washed with water, dried and used as a cadmium negative electrode.

Using this cadmium negative electrode, a comparison was made with a sealed type 2-cell-cadmium storage oil AA battery. The battery configuration conditions were as follows.

Nickel positive electrode: A known sintered nickel electrode with plate dimensions of 2
05 x 38 am, thickness 0, 6M separator; polyamide non-woven fabric with dimensions 650° x 4
271M1 Thickness 0.2 mm Solution: 6.6 noills of lithium hydroxide dissolved in a 30 mm aqueous solution of caustic potash is used per cell. 111j (with the addition of 320 $ of carbonyl nickel powder as an additive) using base 4f and a negative electrode constructed in the same manner as in (A). B), paste 'a' which also added 450g of carbonyl nickel
: The negative A umbrella used is ・1゛, and the output is (G).

Before testing the battery, the utilization rate of each of these cadmium anodes should be determined using the same electrolyte as electrolyte, and as a counter electrode, phosphorus having a sufficient i, (approximately 1oAh).
Using two formed nickel electrodes, each cadmium electrode was sandwiched between them, and the utilization rate at 0.20 was investigated. the result,'
Whereas the cadmium negative electrode of battery A was 86%,
66% for cadmium negative electrode for battery B, 72% for battery C
Met. Person's filling/y capacity was 4.5Ah, so the actual weight was 3.825Ah, and B's filling weight was 4.4
Since it was Ah, it was 2.904Ah, and the charge for C was 4, and because it was QAh, it was 2.88Ah.

In other words, adding more conductive agent naturally increases the utilization rate, but
The actual discharge capacity will be smaller. In contrast, in the present invention, a large utilization rate can be obtained with a small amount of addition [1 amount].

Next, as an example of battery A, B, C and discharge, 6
C discharge was performed. As a result, the average voltage is A 1, 1
2) In contrast to ■2, iJ: 1.09V in B, 1.1 in G
oV, and A was slightly better.

As an example of charging conditions, when we performed rapid charging at 1C, we found that the maximum internal battery pressure at O'C was 3.
Ky/ci was 7' in B? '
At 10 fr, C, it was 9 Ky/cA, indicating that A well absorbed oxygen from the nickel positive electrode generated during charging. This is because in humans, a 1.1 utilization rate can be obtained by simply adding a small amount of electrocardial agent, so the number of filling containers is increased, and therefore, more gold, N4, and cadmium, which absorbs oxygen gas and reacts, per charge. This is because hydrogen can be made to exist, and because it also has a large amount of uncharged cadmium hydroxide, hydrogen is generated per 1iJ 1lr. Therefore, hydrogen generation is also A
is the least common and is hardly recognized, whereas B,
Occurrence was observed in C.

When I repeated one cycle of charging and discharging under the conditions of 0.15G charging and 0.5G discharging, 'EL pond A and Q,↓
There is no abnormality even if 100 discharges are e f at the 900 cycle llj point/(However, Q at C is SOO cycle 11.
When 100 points were centered at 5 points, there was a potential low-toe caused by the cadmium negative electrode, and in case of B, a JJl phenomenon similar to that of C was observed at 850 cycles. This is because, as mentioned above, humans have a large amount of cadmium available for use.

In addition, although the case where only nickel flakes were used was described in the example, it is preferable to mix and add nickel flakes with nickel powder from the point of view of price, and the mixing ratio is 60% of nickel flakes.
It is preferable to set it to J weight % or more.

In addition, it is preferable to use 6 to 20% by weight of the active material in the body.Effects of the Invention According to the present invention, the utilization rate of the non-sintered cadmium negative electrode is improved, and the rapid charging characteristics are improved. 'It can also improve your life.

Claims (1)

[Claims] Active materials containing mainly cadmium oxide or cadmium hydroxide 9
q that nickel flakes were added to the matsumaman! Non-sintered cadmium negative electrode with f-characteristic.