JPS6271168A - Nickel positive plate of alkali storage battery and its manufacture - Google Patents

Abstract

PURPOSE:To improve discharge characteristics of an alkali storage battery by making an active material is 3-layer structure where a layer made mainly from cobalt hydroxide and the like is sandwiched between two layers which are made mainly from nickel hydroxide. CONSTITUTION:On a porous metal substrate, first layer made mainly from nickel hydroxide is formed on which second layer made mainly from cobalt hydroxide or made by chemically oxiding the cobalt hydroxide layer into a layer made mainly from cobalt oxide is formed. Third layer made mainly from nickel hydroxide is formed on the second layer to make a positive plate. Namely, a layer made mainly from cobalt hydroxide or cobalt oxide is sandwiched between two layers made mainly from nickel hydroxide. By this configuration, active material utilization rate and discharge voltage characteristics can be improved even when the active material is packed at high density.

Description

[Detailed description of the invention]

Industrial Application Field The present invention has a sandwich structure between two layers containing nickel hydroxide as the main component; A nickel positive electrode plate for alkaline storage batteries, or even a nickel positive electrode plate of the above structure.
The present invention relates to a nickel positive electrode plate for an alkaline storage battery in which a layer mainly composed of cobalt hydroxide or cobalt oxide is also formed on the surface of the E electrode active material. Problems to be Solved by Conventional Technologies and Inventions Conventionally, nickel positive electrode plates used in alkaline storage batteries are made by sintering carbonyl nickel wood in a porous sintered nickel substrate in a reducing atmosphere, with nickel salt as the main component. It was fabricated by the method of impregnating the nickel substrate with an acidic solution, concentrating 1 to 2 times, and immersing it in a hot alkaline solution to fill the pores of the nickel substrate with nickel hydroxide as the main component and 16 positive active material. Recently, devices using alkaline storage batteries have become smaller, and there is a growing demand for an increase in the packaging density per unit volume of π batteries, but the conventional nickel positive electrode plate In addition, the sintering type 14) Jili's 11!I r was not able to meet such market demands.
There is a foamed nickel positive electrode plate in which sponge-like nickel is physically filled with a positive electrode active material layer containing nickel hydroxide as the main component, but in this case, when the amount of active material powder is increased, the active material There is a problem that the i31+4 usage rate decreases, and the actual capacity density is 11I], so no increase is observed, and the potential characteristics during discharge deteriorate. There are two possible ways to increase the capacity of a nickel positive electrode plate: increasing the amount of positive electrode active material and increasing the active material utilization rate. In the conventional electrode plate, the dimension is close to the limit W, and if it is increased further, the capacity will increase slightly, but the potential characteristics during discharge will deteriorate, which is not appropriate. On the other hand, as a method to increase the active material utilization rate, a few percent of cobalt salt is generally added to the acidic nickel salt impregnation solution, and cobalt hydroxide is uniformly dispersed in the active material after the impregnation process. ing. According to this method, the utilization rate of the active material is not high, and although the high-temperature characteristics are improved, the effect of improving the utilization rate itself is not so large, and it is insufficient for increasing the volume and deterioration of the nickel positive electrode plate. Recently, as a way to improve the performance of nickel positive electrode plates,
Mainly, three known RL techniques have been proposed. Examples of known technology 1 include JP-A-51-121743 and JP-A-51-12174453.
6.0 cobalt sulfate or pl]4,0-G,8
When the cobalt acetate solution is eroded and the cobalt salt is converted to cobalt hydroxide, the temporary volume h1 increases by 14. Known technology 2, for example, L'1 period 16375/1986
There are three wings, and this technology combines a plate holding nilyl hydroxide with cobalt nitrate. J: It has operations and effects similar to those of the known technique 1 of infiltrating into an aqueous solution and then subjecting it to alkali treatment to form a layer of cobalt hydroxide compound of 0.5 to 5 wt% active material. It is something. In these technologies, the structure of the active material is macroscopically a two-layer structure, and a layer of cobalt hydroxide is formed on the outside of nickel hydroxide. As a known technique 3, for example, there is Japanese Patent Publication No. 57-5018, and this technique uses cobalt as the main component and a filter impregnating liquid at least once to produce a positive electrode plate, thereby producing unformed cadmium that has not been precharged. When a battery is assembled using the negative electrode plate as the other electrode, although most of the cobalt in the positive electrode can be charged, only about 20 to 25% of it can be discharged, so the capacity of the cobalt that cannot be discharged is larger than the negative electrode. It has the same effect as charging. However, the content is cobalt 1
When using an impregnating liquid with n as the main component, l! ! 1 and the optimum amount of cobalt compound to be impregnated is not specified. In other words, an impregnating solution containing cobalt salt as the main component can be used either first or last, and there are many problems with impregnation and extraction of balt compounds that reduce the active material utilization rate. Even if the range < 19 i), it would be good. The positive electrode plates according to conventional known techniques 1, 2 and 3 as described above are more likely to have fillers than conventional positive electrode plates in which cobalt hydroxide is uniformly dispersed in the active material. 1 Utilization rate will improve. However, this effect is significant when the active material filling density in the porous metal U plate is not so high and the discharge rate is not so high, but when the active material filling density is high, this effect is I
There was a drawback in that the effect of L reduction was hardly recognized, especially at high rate discharge. The present invention is based on the proposals of the above-mentioned known techniques 1, 2 and 3, but is it at all? Ii This fact was discovered through experiments and overcame the shortcomings of the above-mentioned technology. Packed with 71 living things in 1! I'm in a bad mood in the morning

[, Shi51ka? ! This invention provides a positive (Φ) treatment in which the electric potential characteristics of J3 and Ir1 are significantly improved.In other words, the present invention is based on a detailed study of the formation state of cobalt hydroxide. The i!12-layer structure is such that a layer containing nickel hydroxide as the main component is formed on the outside of the nickel hydroxide as in the known technique 1.2. In between, a layer containing cobalt hydroxide as the main component, and its hydroxylation= ] Cobalt oxidation forms a layer of Cobal 1 ~ Phosphate ↑ Formation of three or more layers of sand German knee structure. By doing so, we can improve the electrical properties of active materials and the dependence of each electrical energy in a highly dense state of active material filling, which could not be achieved with conventional manufacturing methods. JT was created based on the discovery that it was possible to create a nickel positive electrode plate with good CJ properties.Roughly speaking, in the present invention (the structure of the four active materials, and the state of the porous rot plate used) As a result of our investigation, we found that by forming a passive film on the surface of the Ll plate, the active material utilization rate, the discharge potential 1h property, and the discharge sea 1-dependence of each of them were further improved in a state where the active material packing density was high. We have also found that there is C. To solve the problem, the present invention first forms a layer mainly composed of nickel hydroxide on a porous metal plate as a first layer. , and then a second layer on top of the groove, which is a layer mainly composed of cobalt hydroxide.
Alternatively, cobalt hydroxide [.] is chemically or electrified to form an FM containing cobalt oxide as the main component, and then As the third layer, a layer containing nickel hydroxide as the main component is formed.In other words, between the two layers containing nickel hydroxide as the main component, there is cobalt hydroxide or cobalt oxide 1111'c. By forming a layer with + component, it was impossible to achieve 1'7 in the past.
Even in a state where the active material packing density is high, the filling chamber 71, the discharge potential characteristics, and the dependence n'r'I on each discharge wire 1 are made to be satisfactory by using 1 il of nickel positive electrode plate. Furthermore, by forming a layer mainly composed of cobalt hydroxide as a fourth layer on the surface of the above-mentioned positive electrode plate having the Lindidge structure, it is possible to further increase the active material utilization rate by several percentage points. . In this case, the mucus utilization rate at a discharge current of 1CΔ is I:L
Almost 100% 1" becomes 1.Also used porous price r
By forming a passive film of metal oxide on the surface of the tA substrate, the utilization rate of active material 't1 and the discharge potential characteristics of tI can be improved.
It is possible to further reduce the dependence on electric current. Examples Experiments and examples related to the present invention are shown below. Experiment 1 Using nickel as the main component and 16 impregnating liquid, the chemical infiltration method was repeated several times, and the 1st F+'i 1.1 hydroxy acid (mainly Hnickel) was added to the sintered nickel base. A layer was formed as a component.Next, the 1st and 2nd layer was performed once using solutions of cobalt nitrate at various concentrations.
A layer of cobalt hydroxide was formed, and the water was electrolytically oxidized to form a cobalmy oxide layer of cobalt hydroxide M. Furthermore, a third layer containing nickel hydroxide as a main component was formed thereon in the same manner as the first layer. The active material utilization F of the nickel 11-1 layer (electrode plate iY△) produced in this way was measured at a temperature of 1.250 (20°C> in a KO11 solution. Regarding the cobalt nitrate impregnating solution, after forming the second layer of cobalt hydroxide alone, this cobalt hydroxide is electrochemically oxidized. Electrode plates (referred to as electrode plates 8Y and 8B) on which a layer containing the active material was formed were prepared, and the usage rate of the nickel hydroxide filled as an active material was measured in the same manner. The ratio of the 2v40th cobalt compound to the amount and the ill ratio of the active material utilization rate are shown.・Calculated as mine.For the nickel sintered substrate, mix carbonyl nickel T't) powder with water and glue to make a nickel slurry, and apply the nickel slurry to a metal plate made of iron with 1 nickel metal. After that, nickel was sintered at 900°C in a reducing atmosphere. In FIG. 1, in the case of the electrode plate group Δ in which cobalt hydroxide 8 is electrochemically oxidized at the second inlet, the active material is Usage rate is high. Which reversible electric potential of cobalt oxide and cobalt oxide of A palm hydroxide and balt hydroxide is higher than that of nickel? , and from the charging/discharging potential 14, li
f, charging ■, 1 is nickel hydroxide J, hydroxide = ] Balt is charged to cobalt 1 such as cobalt hydroxide, and acid 1 arsenic is charged, and when discharging, A x It is said that the discharge of nickel hydroxide precedes the discharge of nickel hydroxide, and that the cobalt oxide of 41 hydroxide: 1 balt cap has good conductivity.
) + 15, it is thought that the second layer of cobalt alone has an effect as a current collector, increasing the frequency of the active material f・1. It is unclear why the active material utilization rate decreases when the number of particles increases.On the other hand, the horizontal plate RY8 in which the cobalt hydroxide alone in the second layer was not electrochemically oxidized In the case of , the usage rate of active material 11J is hardly increased,
Is the result equivalent to 5 for the previous electrode group A? It has become. The reason for this is that in forming the third layer, which is mainly composed of nickel hydroxide, impregnation with a solution of nickel nitrate [
1. 'i, the second layer of hydroxide] is dissolved, and in the subsequent neutralization process, cobalt hydroxide is fractionated in nickel hydroxide, reducing its current collector effect. result,
It seems that the active material utilization rate did not increase. From this, when forming a layer consisting of a cobalt compound alone, the layer containing nickel hydroxide as the main component before and after it will
j Since it is considered necessary to prevent mixing, when producing a positive electrode plate by a chemical impregnation method, it is necessary to
Im included? It is necessary to convert it into a cobaltic acid monomer which is difficult to dissolve in 2xh. But 1 school included? When filling the active material with 2 people 1 space outside the room, for example, physically fill the active material into the foamed electrode plate J, 1
In the case of J, this is the limit [not Yu, but cobal hydroxide [without oxidizing ~]) a living substance? When the filling density of 1 is high, make sure that the filling t and j are high. In this experiment, oxidation of hydroxyl (Tl)- was performed electrochemically, but other methods include hydrogen peroxide, hypochlorite, wood acid, and peroxide. Similar results were obtained when using an oxidizing agent such as potassium chloride or heat treatment in an air atmosphere to avoid oxidation. '7. Experiment 2 Among the samples of the electrode plate CYΔ prepared in Experiment 1, in which an improvement in the active material utilization rate was observed, the sample with O, 61% and the sample with the highest amount of cobalt compounds in the second layer, respectively, had the lowest amount of cobalt compound in the second layer.
, 0 mol % of the sample, a chemical impregnation method was performed once to produce a positive electrode plate (referred to as electrode plate groups C1 and C2) in which a layer of cobalt hydroxide alone was formed as the fourth layer, Experiment 1: What about living things? 1 usage rate was measured. Figure 2 shows 1I for the amount of nickel hydroxide filled as an active material.
We received the relationship between the ratio of cobalt hydroxide in ffl and the active material utilization rate. As can be seen from Figure 2, in the case of electrode plate group C1 in which the amount of cobalt compound in the second layer is 0.6 sil%, the amount of cobalt hydroxide in the fourth layer is 0.8 to 7.0. Live substance r in the range of mol%
1 utilization rate has increased to almost 100%. on the other hand,
The hanging of the cobalt compound in the second layer is 10. In the case of Otru% plate group C2, the utilization rate is close to 100% (
Y, the cobalt hydroxide fabric in the fourth layer is in the range of 0.4 to 6.0 mol%. When determining the optimal value for the cobalt content M from the results of Experiment 1 and this Experiment 20, the content of the cobalt compound in the second layer is O, G~10, Ot-le%,
When the content of the cobalt compound in the fourth layer is in the range of 0.4 to 7.0 mol%, a positive electrode plate with a high active material utilization rate can be obtained. The effect of active material 1 on the active material utilization rate of the inventive product and the conventional product shown by the known technology
1. The influence of packing density was investigated. In the positive electrode plate according to the present invention, among the electrode plate group A (3 layers I^i) prepared in Experiment 1, the amount of the cobalt compound in the second layer is equal to the amount of niraglu hydroxide filled as the living substance 71. On the other hand, the positive (anti) (r1Δ') which is 3Ti 96,
It has a four-layer structure similar to Samples C1 and C2 prepared in Experiment 2, and 1- of the -f baltic compound in the second layer is 3 [Le + 36
(Sample C') in which the cobalt hydroxide content in the fourth layer was also 2 mol % was used. Nickel oxide i!
After forming the 11111 layer, a positive (4k (reverse) sample r'l D) was formed in which cobalt hydroxide was formed on the large surface of A.
was used. The hanging of a large surface of cobalt hydroxide was adjusted to 3T nyl% for the nickel hydroxide spray. In addition, the packing density of the packing material on the horizontal axis is calculated assuming that impregnated nickel hydroxide and cobalt hydroxide each follow a 1-electrof reaction. It is clear from Figure 3 that in the sample prepared by applying the known technique, a decrease in active material utilization (lI7) is observed as the active material density increases, whereas Samples A and C'c have almost no decrease in active material utilization, and have lower IEt~temporary Q'gm than conventional products.
It can be seen that it is suitable for This is considered to be because the conductivity of the active material in the product of the present invention is better and more uniform than that in the conventional product. Experiment 4 In Experiments 1 to 3, an aQ solution of cobalt nitrate was used to form the second and fourth cobalt compound layers, but in this experiment, this impregnating solution was VIrI. In the case of a mixture of cobalt acid and nickel nitrate, the active material utilization rate of one reprint is set as 8 + 11 for the structure similar to the above (see details Δ), and the minimum The content of the necessary cobalt compound was determined.As a sample electrode plate, the a of the cobalt compound in the second layer was set to 4 mol% with respect to the amount of niracle hydroxide filled as an active material, and the electrode plate (electrode plate group [and ) was prepared using a chemical impregnation method. The relationship between the active material composition of the second layer and the active material utilization rate is explained in the fourth section.
As shown in the figure. '; As can be seen from Figure 54, the active material utilization rate is affected by the active material t1 composition. As the content of cobalt compounds (i) decreases, the living material 71 ratio also decreases.
'1 composition is around 70 mol% of cobalt compounds, active material 11
The publication rate decreases significantly, and if the content is lower than that, there is almost no effect of forming the second layer containing the cobalt compound as the L component. From this, it is desirable that the active material composition contains at least 70 mol% or more of a cobalt compound, preferably 100 mol%.
Nijii. Experiment 5 In this experiment, nickel-baked Fl! In order to examine the influence of using i-form as an active material, two types of nickel sintered substrates were prepared, and the performance of the electrode plates filled with the active material using the same impregnating solution and the same method was investigated. The same nickel slurry used in Experiments 1 to 4 was applied to a metallic current collector.
One was sintered at 900°C in a reducing atmosphere (substrate 1), and the other was sintered at 200°C in an air atmosphere while adding water vapor at q o o'c in a reducing atmosphere.
And the heat flood 1! 1! A product in which a passive film of nickel oxide is formed on the surface of a nickel sintered body (substrate 2)
It is. Using these two Niracle sintered substrates, the pole tf2 of Experiment 1 was
f! In the same manner as ¥△ (3-layer collapse), a positive electrode plate was prepared in which the suspension of the =1pal1-compound in the second layer was 4%, and i
71 Discharge rate dependence of Igawa ratio and discharge intermediate potential (I
Figures 5 and 6 show the results of the gender investigation, respectively. Na J5
, a passive film of nickel oxide is formed on the surface of the nickel sintered body.
Set it to 2. In the comparison of active material utilization rates in Figure 5, A1 and A2
There is no difference between J3 and lυ for a low-temperature discharge of 0.2CA, but the difference increases as the discharge rate increases to 3CA and 10C△.This is due to the discharge in Figure 6. The intermediate potential had a similar tendency, and a non-Kh-state film of nickel oxidation was formed on the surface of the nickel sintered body! ~ Plate A2 was compared to A1, which did not have this type of film. The oil that prevents the decline in electrode plate strength due to active material has low discharge rate dependence, ;':'active material M'l in BL rate discharge
A special effect of ♀7i was found that there was little decrease in the discharge potential characteristics. This is because in the case of sample Δ1, which does not form a full ru: film on the surface of the nickel sintered body, the acidic impregnation solution corrodes the nickel chains, resulting in a decrease in conductivity, and the area covered by the nickel sintered body. 1) The contact area between the active material and the active material decreases.
This is thought to be due to the fact that the performance deterioration in high-rate discharge appears to be more pronounced. This conversion of nickel sintered bodies into active materials is known to occur not only during the chemical process (but also at a critical potential during charging of the positive electrode plate), and it is known that nickel sintering in J3 in actual use of batteries occurs. By turning the aggregate into an active material, Ij
! It is expected that the temporary performance will change and the battery performance will gradually deteriorate. In contrast, trial 1△ in which a passive film was formed
Tit in 2, the corrosion of the nickel sintered body by the acidic impregnating liquid and the charging of the positive electrode plate in the nh book caused the 8 to 1 force of the 2-9 ru firing f1'4 body? 7 does not occur, the original good performance of the electrode plate is maintained (11).In other words, in order to stably (! Forming an indestructible film of nickel acid on the surface of the sintered body is effective in preventing activation of the nickel sintered body during the active material impregnation process and charging of the positive electrode plate. The results of the above five experiments were compared between the positive electrode plate and the conventional product based on 191). !Temporarily used in Experiment 4, Yake', Hayakari 1
and 3 scales of 2-2 tumors (85% porosity) and 4-film-like nickel porous material (95% porosity).
did. Example 1 (Product of the present invention) A calcined wood board 1 was impregnated with a 5.0'E/2' solution of lr1 acid ninonoric acid and neutralized with hot alkali at °C. Filling the pores of the nickel sintered body with nickel hydroxide) The process of the usual chemical impregnation method is performed three times, and the first
A layer of nickel hydroxide is formed in the second layer, and then one step of the chemical impregnation method is performed using a cobalt nitrate aqueous solution of 1.4 [Lua] (7,000,000 ml of hydroxyl). Forms the Baltic and German tonks/:t!2, specific gravity 1,250
(20°C) In K011 water ('8 solution), 1 u of hydroxide-balt was dissolved. After washing and drying, the same process as in the formation of the first layer [] was carried out. te, fL'
;'°Impregnation method] - Repeat steps 5 times to form a third layer of nickel hydroxide, and repeat (~1 repeat).
1F and 1F). Example 2 (product of the present invention) Sintered J, 1 (except that 2 was used) (Example 1) A positive electrode plate was made in the same manner as in Example (i) 1, and this was used as a test tl G. 1゜Example 3 (Product of the present invention) In Example 1, ff'FJ L t: Test 1'' 1F as base, roughly 2.2 ru/no l, rl l!f Kobal 1~
Repeat the chemical impregnation process once using water Fil H to form a layer of hydroxide T] Balt 11 for the 1st layer and make a positive (assembled plate 3, which is referred to as sample rF11). Example 4 (product of the present invention) 'J produced in Example 2, material 0zen04■, implementation 1311
A fourth layer of cobal hydroxide 1 to grade A 1 was formed in the same manner as in 3 to form a positive (assembled board). This was designated as trial t!l I. Example 5 (conventional product) The chemical impregnation process was carried out on the bonded substrate 1 8 times using a nickel nitrate aqueous solution of 5.0 silua/2 (1, nickel sinter filling (filling the substrate with nickel hydroxide, then 2.6'f) Using an aqueous solution of cobalt nitrate with a concentration of 100% and 100%, a layer of hydroxide-1 and 1-111 was formed on the surface using the pore impregnation process once. This was used as a positive electrode plate. Try it as J. Example O (conventional product) Sintering process
ClIIrI acid cohal 1~) 7/chemical process step 8 times using an aqueous solution of nickel sintering;
A positive electrode plate was prepared by filling the ash with a mixture of nickel hydroxide and cobalt hydroxide. Let's call this test nK. Implementation 1? j 7 (Product of the present invention) 86 parts of nickel hydroxide, carbonyl nickel:
1 less than 10 parts, metal cobalt f5) last 4 parts] day 2
At the end of ilN Qn of 00 mesh pass, there is water and water [
Add 1-su to active material base 1~
σ5 +, 1/. 5Q9(,
After 1 hour of physical filling, a layer 4 containing nickel hydroxide as a main component (1) 14th layer was formed. Next, using an aqueous solution of L4 [Lua's acid] Pal 1 (chemical impregnation)
The remaining active material paste was treated in the same manner as in the formation of the first layer "1" to form the second layer of hydroxylation. The third layer is formed by forming a layer containing one layer of sluice-forming Nitsunonol as the main component.In addition, as a step, impregnating it with ±3 sparge II. 1 murder, 9 beggar press (
j 1 piece 1 ~ (I folded it. Take a sample of it. 18 (conventional product)
! , +1 was filled with the same active material base 1-filament as used in Example 1-17. Add this to Sample M.Example 9 (Conventional Product) Sample M49 prepared in Example 8 was further converted into C using a cobalt nitrate aqueous solution containing C morph. Perform the impregnation process once and apply the hydroxide surface to one cuff per person] Pal 1~
! A P-layer was formed and the IF polar root was formed. Try this 21
Let it be N. Table 1 shows the theoretical intervals of the test t1 r-N using the above J, and Table 2 shows the active material composition. The theoretical value was calculated assuming that nickel hydroxide and cobalt hydroxide follow one electrician reaction. Next, 6 samples 71 were cut into dimensions of 40 x 40 (mn+), and the excess ratio n 1.250 (20°C) KO! 1
In an aqueous solution, we investigated the discharge rate dependence of sintered cadmium negative (using two sheets of the same size as opposed to each other, charging and discharging at t'+, active material usage 12 and discharge potential 1) and L = o. Jj
, the chemical charging for the first recycle is carried out to 100% of the theoretical capacity at 11 currents of 0.1C△, and after the 2nd recycle, it is carried out to 120% at a current of 0.2CΔ, and the discharge is carried out at a current of 0.1C△ and 120% of the theoretical capacity. Up to. The seventh [4] shows the dependence of the active material utilization on the discharge rate in the 2:5 impregnation method using a sintered substrate. , use; from high r [:= If > G > Fn-J
> K, and a layer of oxidized cobalt hydroxide is formed between two layers of nickel hydroxide to form a sandwich structure, product 1.11. G, I” conventional product J
, the usage rate is clearly improved compared to 1. Also 3
CΔ, 10C△? In 3-rate discharge, the difference between the product of the present invention and the conventional product is further expanded. This direction is similar to bIi''il in Fig. 8, which shows the discharge potential characteristics investigated. Also, sample 1 in which the active vAYff has a 41Fl structure.
It has a three-layer structure, Sample 1[, and Sample 1.G has an improved active material utilization rate compared to Sample 1, which has a nickel sintered body and has a passive film of nickel oxide formed on the surface of the nickel sintered body. G is a sample that does not
, ) 1, an improvement in the discharge charge retention characteristics was mainly observed. In addition, in Figure 8, Jj and the electric power 1η of test FI K are 0.2.
The low T-discharge of C△ is considered to be due to the fact that the content of carbon hydroxide [Pal I] dispersed in the active material is greater than that in other chambers (1). In addition, Figures 9 and 10 show the performance of samples L to N in which the foam-like nickel porous body was immediately filled with filler 71. 7 and 8, a sample of the product according to the present invention (L) is a sample of the conventional product (T). It can be seen that the active material utilization rate and discharge potential characteristics during high rate discharge are r4 better than those of 1M and N. (on top of this) is filled with active material by a method other than chemical impregnation.
If you do, t,! , good performance in a state where the active material packing density is high without oxidizing Nibalt hydroxide in the second layer):f
The discharge characteristics were 17%. As mentioned above, the product of the present invention clearly has better discharge characteristics at -°C than the conventional product. The effects of light III'l as shown in the above examples, and the present invention,
A third active material 711M in which cobal hydroxide 1 to cobal hydroxide 1 or toco 1 mainly composed of cobal l-oxide was formed between two layers containing nickel hydroxide as the main component by dipping in 1:11 in Linder-Buch. By adding 11 to the construction, 1 from 1m! ++
J, 1q of nickel positive electrode plates for alkaline storage batteries with an excellent discharge rate of ↑1 can be obtained. , said 33 layers! 14
By forming a layer mainly composed of cobalt hydroxide as a fourth layer on top of the pickle, it is possible to further improve the utilization of the filler material by several percentage points. In order to stably achieve the effects of the present invention, it is effective to form a passive film of a metal-resistant compound on the surface of the porous metal substrate. Discharge characteristics are 1
! ′? It will be done.

[Brief explanation of drawings]

Figure 1 shows the relationship between the cobalt content of the second layer [ ] and active material utilization r with respect to the increase in impregnation. n Hanging and story substance use 1・-
Figure 3 shows the relationship between the active material packing density of the nickel square plate of the present invention and the conventional product, i\j +lI
Figure 1 is a diagram showing the relationship between the active material composition of the second and fourth layers and the active material (11), Figure 5 is a diagram showing the relationship between the active material composition of the second and fourth layers, and Figure 5 is a diagram showing the relationship between the active material composition of the second and fourth layers. Fig. 6 shows the influence of the cutting board surface on the discharge rate of the 7t2 lightning level 1) (nickel sintered on the discharge rate of the room).
Figures 7 and 9 showing the influence of nickel sintered grass roots surface
The figure shows a comparison of the IJ electromagnetic rate 1Δη of the active material of Niracle 1t-4li of the present invention and a conventional product,
? Figure 4''S8 and Figure 10 are diagrams showing a comparison of the 1h discharge potential of the nickel positive electrode plate of the present invention and the conventional product. t(~Jri)) Prisoner's message Fuporoki (invitation θn sai 5 Σ 瑑 and one = electric (ζ cutji [Otsu Higobun r 8 beg w Go (CA) λ 7 prisoner 2 sentence *! 71 (CA noo 8 figure λ 9 times ceremony) f t* 'jAJ way lo prisoner tUt, Δ cane (7'A)

Claims (11)

[Claims] (1) In a nickel positive electrode plate in which a positive electrode active material layer containing nickel hydroxide as a main component is formed on a porous metal substrate,
The positive electrode active material layer has the following structure, that is, the first layer on the porous metal substrate is a layer mainly composed of nickel hydroxide, and the second layer is cobalt hydroxide or cobalt oxide. It is a layer whose main component is
The layer is a layer mainly composed of nickel hydroxide, that is, a layer mainly composed of cobalt hydroxide or cobalt oxide is formed in a sandwich structure between two layers mainly composed of nickel hydroxide. A nickel positive electrode plate for alkaline storage batteries characterized by: (2) The amount of cobalt compound contained in the second layer containing cobalt hydroxide or cobalt oxide as a main component is 0.6 to 10.0 mol% relative to the amount of nickel hydroxide.
A nickel positive electrode plate for an alkaline storage battery according to claim (1). (3) The content of the cobalt compound in the second layer mainly composed of cobalt hydroxide or cobalt oxide is 7.
The nickel positive electrode plate for an alkaline storage battery according to claim (1), wherein the nickel content is 0 mol% or more. (4) A nickel positive electrode plate for an alkaline storage battery according to claim (1), characterized in that a passive film of metal oxide is formed on the surface of a porous metal substrate. (5) After the porous metal substrate is impregnated with an acidic solution containing nickel salt as its main component, the usual chemical impregnation process of concentration and alkali treatment is performed several times to form the first layer on the porous metal substrate. A layer containing nickel hydroxide as the main component is formed, and then a chemical impregnation process is performed at least once using an acidic solution containing cobalt salt as the main component to form a second layer containing cobalt hydroxide as the main component. After forming a layer, the layer containing cobalt hydroxide as a main component is electrochemically or chemically oxidized to change the layer containing cobalt hydroxide as a main component into a layer containing cobalt oxide as a main component, and then forming a first layer. A method for producing a nickel positive electrode plate for an alkaline storage battery, characterized in that a chemical impregnation process is performed several times in the same manner to form a third layer containing nickel hydroxide as a main component. (6) In a nickel positive electrode plate in which a positive electrode active material layer containing nickel hydroxide as a main component is formed on a porous metal substrate,
The positive electrode active material layer has the following structure, that is, the first layer on the porous metal substrate is a layer mainly composed of nickel hydroxide, and the second layer is cobalt hydroxide or cobalt oxide. The third layer is a layer mainly composed of nickel hydroxide, and the fourth layer above it is a layer mainly composed of cobalt hydroxide, that is, water. A nickel positive electrode plate for an alkaline storage battery, characterized in that layers mainly composed of nickel oxide and layers mainly composed of a cobalt compound are laminated alternately. (7) The amount of cobalt compound contained in the second layer containing cobalt hydroxide or cobalt oxide as a main component is 0.6 to 10.0 mol% with respect to the amount of nickel hydroxide.
A nickel positive electrode plate for an alkaline storage battery according to claim (6). (8) The amount of cobalt hydroxide contained in the fourth layer mainly composed of cobalt hydroxide is 0.4 to 7.0 mol% with respect to the amount of nickel hydroxide. A nickel positive electrode plate for an alkaline storage battery as described in scope item (6). (9) Claim No. 6, wherein the content of the cobalt compound in the second layer and the fourth layer whose main component is cobalt hydroxide or cobalt oxide is 70 mol% or more.
Nickel positive electrode plate for alkaline storage batteries as described in . (10) Claim (6) characterized in that a passive film of metal oxide is formed on the surface of the porous metal substrate.
Nickel positive electrode plate for alkaline storage batteries as described in . (11) After impregnating a porous metal substrate with an acidic solution containing nickel salt as its main component, the usual chemical impregnation process of concentrating and alkali treatment is performed several times to form the first layer on the porous metal substrate. A layer containing nickel hydroxide as the main component is formed, and then a chemical impregnation process is performed at least once using an acidic solution containing cobalt salt as the main component to form a second layer containing cobalt hydroxide as the main component. After forming a layer, the layer containing cobalt hydroxide as a main component is electrochemically or chemically oxidized to change the layer containing cobalt hydroxide as a main component into a layer containing cobalt oxide as a main component, and then forming a first layer. After performing the chemical impregnation process several times in the same manner to form a third layer consisting mainly of nickel hydroxide, the chemical impregnation process is performed at least once in the same manner as in the formation of the second layer. A method for producing a nickel positive electrode plate for an alkaline storage battery, which comprises performing the above steps to form a layer containing cobalt hydroxide as a main component as a fourth layer.