JP3410340B2 - Prismatic alkaline secondary battery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] BACKGROUND OF THE INVENTION 1. Field of the Invention
Regarding batteries, in particular, square alkaline secondary batteries with improved electrode groups
It relates to a pond. [0002] 2. Description of the Related Art As an alkaline secondary battery, nickel
Known are dome rechargeable batteries and nickel-metal hydride rechargeable batteries.
ing. The battery structure of this secondary battery includes a positive electrode and a negative electrode.
Formed by stacking
Known is a square structure in which the pole group is housed in a bottomed rectangular cylindrical container.
ing. In such an alkaline secondary battery,
Relatively easy to manufacture and low manufacturing cost
Therefore, paste electrodes are widely used for the positive and negative electrodes.
ing. For example, paste-type hydrogen storage alloy electrodes
Usually, hydrogen storage alloy powder, sodium polyacrylate
And thickening hydrophilic like carboxymethylcellulose
And a conductive material such as carbon black,
To prepare a paste by kneading with water as
After the strike is applied to the surface of the current collector, the
It is produced by cutting into pieces. However, said
For alkaline secondary batteries, the charge / discharge cycle progresses.
It is desired to suppress the accompanying increase in internal pressure. [0004] SUMMARY OF THE INVENTION It is an object of the present invention to provide a laminated
By improving the electrode group, as the charge / discharge cycle progresses,
To prevent the internal pressure from rising and use a long-life alkaline alkaline rechargeable battery.
It is something to offer. [0005] A square arc according to the present invention.
Rechargeable batteries are bottomed rectangular cylindrical containers that also serve as negative electrode terminals.
And a positive electrode and a negative electrode housed in the container,
With the intermediarySo that the outermost layer is the negative electrodeAlternately
The electrode group manufactured by the
Alkaline electrolyte and placed at the opening of the container
With a sealing memberPrismatic alkaline rechargeable battery,
In the negative electrode, a negative electrode layer containing a negative electrode active material is provided on both surfaces of a current collector.
Having a supported structure,Negative electrode located in the outermost layerso
Indicates that the negative electrode layer located inside is
1.1 to 1.5 times thickerNegative electrode other than the outermost negative electrode
Is the thickness of the inner negative electrode layer and the outer negative electrode layer.
Are equalIt is characterized by the following. [0006] BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a square alkali according to the present invention will be described.
The secondary battery will be described with reference to FIG. Also serves as negative electrode terminal
An electrode group 2 is housed in a bottomed rectangular cylindrical container 1.
You. The electrode group 2 includes, for example, three positive electrodes 3 and four negative electrodes.
The poles 4 are alternately stacked with the separator 5 interposed therebetween.
It is produced by doing. Outside the electrode group 2
The disposed negative electrode 4 is in electrical contact with the container 1.
You. The alkaline electrolyte is contained in the container 1.
You. A rectangular sealing plate 7 having a hole 6 in the center is
Is arranged in the upper opening. Has an opening at the bottom
The bottomed rectangular tubular insulating gasket 8 is
It is arranged between the peripheral edge and the inner surface of the upper opening of the container 1.
You. The sealing plate 7 has the upper opening of the container 1 facing inward.
The gasket is attached to the container 1 by caulking to reduce the diameter.
It is air-tightly mounted via a door 8. Positive electrode lead 9
Has one end connected to the positive electrode 3 and the other end below the sealing plate 7.
Connected to the surface. The cap-shaped positive electrode terminal 10 is
It is mounted on the sealing plate 7 so as to cover the hole 6.
You. The positive electrode terminal 10 has a plurality of gas passage holes (shown in the drawing).
Not open). The rubber safety valve 11 is
The hole is inserted into a space surrounded by the sealing plate 7 and the positive electrode terminal 10.
It is arranged so as to cover 16. Next, the positive electrode 3, the negative electrode 4, the separator 5
And the electrolyte will be described. 1) Positive electrode 3 This positive electrode 3 is made of a positive electrode material containing nickel hydroxide particles.
It is formed from one carried on an electric body. [0008] The positive electrode is, for example, nickel hydroxide particles.
Particles, cobalt-based particles as conductive aids, binders and water
Prepare a paste containing, and fill the paste into a current collector
After drying and pressing, it is cut to the desired size.
It is produced by doing. As the nickel hydroxide particles, for example, a single
Nickel hydroxide particles, or zinc and / or copper
The nickel hydroxide particles co-precipitated with metallic nickel
Can be used. Contains the latter nickel hydroxide particles
The positive electrode must further improve charging efficiency in high temperature conditions
Becomes possible. The charge / discharge efficiency of the alkaline storage battery is improved.
X-ray powder diffraction method for the nickel hydroxide particles
The peak half-value width of the (101) plane is 0.8 ° / 2θ
(Cu-Kα) or more is preferable. More preferred
X-ray powder diffraction of nickel hydroxide powder (10
1) The half width of the surface peak is 0.9 to 1.0 ° / 2θ.
(Cu-Kα). As the binder, for example, polytetrafluoroethylene
Fluoroethylene (PTFE), polyethylene, polyp
Propylene, rubber-based polymer (for example, styrene butadiene
Rubber (SBR) latex, acrylonitrile pig
Latex of diene rubber (NBR), ethylene propylene
Hydrophobic such as latex of diene monomer (EPDM)
Polymer; for example, carboxymethylcellulose (CM
C), methylcellulose (MC), hydroxypropyl
Methylcellulose (HPMC), polyacrylate (example)
For example, sodium polyacrylate (SPA)), polyvinyl alcohol
Alcohol (PVA), polyethylene oxide, CO
Monomer having at least one OX group and vinyl alcohol
(Where X is hydrogen, an alkali metal, an alcohol)
Hydrophilicity (consisting of elements selected from alkaline earth metals)
Polymer; and the like. As the binder
Is one or more selected from the aforementioned polymers
Can be used. Incidentally, the polyethylene, the
Polypropylene and said polytetrafluoroethylene
It can be used in the form of a dispersion. Cobaltization for forming the cobalt-based particles
As the compound, for example, dicobalt trioxide (Co_Two O
_Three ), Cobalt metal (Co), cobalt monoxide (Co)
O), cobalt hydroxide @ Co (OH)_Two を 挙 げ る etc.
Can be. The current collector may be, for example, nickel or nickel.
Metal such as stainless steel or resin plated with nickel
Sponge-like, fibrous, felt-like porous structure
Can be mentioned. 2) Negative electrode 4 The negative electrode 4 has a structure in which a negative electrode layer containing a negative electrode active material is formed on both surfaces of a current collector.
It is formed from those carried on. Such a negative electrode
That is, the negative electrode located in the outermost layer of the electrode group
The negative electrode layer on the group side is the negative electrode layer on the outside (the negative
Extreme layer) is 1.1 to 1.5 times thicker. In the negative electrode located in the outermost layer of the electrode group,
The thickness of the negative electrode layer on the side of 1.1 to 1.
The reason why the thickness is increased five times is as follows. Thick
When the height ratio is less than 1.1, the outer negative electrode layer is thinned.
And the effect of improving conduction between the container and the negative electrode
I can't. On the other hand, if the thickness ratio exceeds 1.5,
The anode between the outermost layer and the conduction between the electrode layer and the current collector deteriorates.
The oxygen gas absorption performance of
You. A more preferred thickness ratio is 1.1 to 1.4 times,
A more preferred thickness ratio is 1.1 to 1.3 times. The negative electrode layer containing the negative electrode active material is formed on both sides of the current collector.
The negative electrode carried on the surface is, for example, the negative electrode active material, conductive
The paste is prepared by kneading the material and binder together with water.
The above-mentioned paste is filled in the current collector, dried, and then molded.
It is manufactured by The thickness of the negative electrode layer on the front and back
However, for a negative electrode with a different
In press molding, the negative electrode layer on one side and the negative electrode layer on the other side
And pressurize so that the thickness ratio becomes 1.1 to 1.5.
Can be produced. As the negative electrode active material, for example, metal
Cadmium compounds such as cadmium and cadmium hydroxide, water
Element and the like. Hydrogen host matrix
Examples of the alloy include a hydrogen storage alloy.
You. [0018] In particular, the hydrogen storage alloy is the cadmium.
Capacity of rechargeable batteries is higher than when using
Is preferred. The hydrogen storage alloy is particularly restricted
Not electrochemically generated in the electrolyte
Hydrogen can be stored, and the stored hydrogen can be easily released during discharge.
Anything that can be issued is acceptable. For example, LaNi_Five , Mm
Ni_Five (Mm is misch metal), LmNi_Five (Lm is
At least one selected from rare earth elements containing La),
A part of Ni of these alloys is Al, Mn, Co, Ti, C
Plural element substituted by elements such as u, Zn, Zr, Cr, B
Element-based, or TiNi-based and TiFe-based
I can do it. In particular, the general formula LmNi_w Co_x Mn
_y Al_z (The total value of the atomic ratios w, x, y, and z is 5.00 ≦
w + x + y + z ≦ 5.50)
Element storage alloy suppresses pulverization as charge / discharge cycle progresses
To improve the charge / discharge cycle life.
You. As the binder, the above-described positive electrode will be described.
One or two selected from the same polymers as
The above can be used. Examples of the conductive material include
Examples thereof include carbon black and graphite. As the current collector, for example, a punched metal
Metal, expanded metal, perforated hard plate, nickel net
Two-dimensional substrates such as
And three-dimensional substrates such as porous metal
You. 3) Separator 5 The separator 5 is made of, for example, polyamide fiber
Non-woven fabric, Polyole such as polyethylene or polypropylene
Finned fiber nonwoven fabrics with hydrophilic functional groups
I can do it. 4) Alkaline electrolyte Examples of the alkaline electrolyte include sodium hydroxide
(NaOH) aqueous solution, lithium hydroxide (LiOH)
Aqueous solution, potassium hydroxide (KOH) aqueous solution, NaO
H and LiOH mixed solution, KOH and LiOH mixed solution, K
It is possible to use a mixture of OH, LiOH and NaOH, etc.
Wear. The prismatic alkali metal according to the present invention described in detail above
According to the secondary battery, the negative electrode located at the outermost layer of the stacked electrode group
The inner negative electrode layer in contact with the separator is
1.1 to 1.5 times thicker than the outer negative electrode layer in contact with the surface
The outermost layer and the container also serving as the negative electrode terminal
The distance to the current collector of the negative electrode located can be shortened,
Improve conduction between the container and the negative electrode located in the outermost layer
Can be As a result, the entire negative electrode in the electrode group
The conductivity is improved, and the oxygen gas absorption performance of the negative electrode is improved.
Internal pressure as the charge / discharge cycle progresses
Ascent can be suppressed. For this reason, the charge / discharge cycle
Of the discharge capacity due to the progress of
An alkaline secondary battery can be realized. [0024] DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings.
Will be described. (Example 1) <Preparation of positive electrode> 90% by weight of nickel hydroxide powder and
Consisting of 10% by weight of cobalt monoxide powder as an electric assistant
0.3% by weight of carboxymethylcellulose in the mixed powder
And 0.5% by weight of polytetrafluoroethylene
Then, the mixture was kneaded in the presence of water to prepare a paste. This page
The paste is filled into a sintered fiber substrate as a current collector and dried.
After that, roll press and roll forming
Positive electrode with structure in which positive electrode material containing nickel is supported on current collector
Were produced. Each positive electrode has a thickness of the positive electrode material of 20
μm, overall thickness 0.6mm, capacity per unit area
Was 650 mAh / cc. <Preparation of negative electrode> Commercial lanthanum-enriched misch metal
Lm, Ni, Co, Mn and Al
What is LmNi_4.0 Co_0.4 Mn_0.3 Al_0.3 Composition of
A hydrogen storage alloy was prepared. Using the hydrogen storage alloy
This was mechanically ground and passed through a 200-mesh sieve. Profit
100 parts by weight of the alloy powder
0.5 parts by weight and carboxymethyl cellulose 0.12
5 parts by weight, polytetrafluoroethylene dispurge
(Specific gravity 1.5, solid content 60% by weight)
2.5 parts by weight and carbon powder 1.0 as a conductive material
Parts by weight and mixing with 50 parts by weight of water.
Thus, a paste was prepared. This paste is used as a current collector.
0.7mm thickness on one side of punched metal
Then, it was applied to the other surface to a thickness of 0.8 mm and dried.
Then, the thickness ratio of the paste layer is set to 1: 1.1.
Hydrogen absorption is achieved by pressure molding using a roller press.
The negative electrode layer containing the storage alloy is supported on both sides of the current collector.
Having a negative electrode layer thickness ratio of 1: 1.1 for the outermost layer.
Four poles were made. On the other hand, the paste is used for both punched metal
After applying 0.7mm thickness on the surface and drying,
Press-molding the hydrogen storage alloy
Having a structure in which a negative electrode layer containing
Six negative electrodes having a pole layer thickness ratio of 1: 1 were produced. Each of the obtained positive electrodes is mainly composed of polyolefin.
With a bag-shaped separator made of non-woven fabric
Negative electrode is placed on the outermost layer by alternately overlapping each negative electrode
The inner negative electrode layer of the negative electrode becomes the outer negative electrode layer.
Two electrode groups having a structure 1.1 times thicker than those of the electrode group were produced. Such an electrode group is formed as a bottomed electrode which also serves as a negative electrode terminal.
After being housed in a rectangular cylindrical container, 7N KOH
And an alkaline electrolyte comprising 1N LiOH,
The F5 size having the structure shown in FIG.
665 mAh) square nickel-metal hydride secondary battery
Assembled. (Example 2) <Preparation of negative electrode> A paste similar to that of Example 1 was prepared, and
Apply the paste to one side of the punched metal current collector
Apply 0.7mm thickness and 0.9mm thickness on the other side
It was then applied and dried. Then, the thickness ratio of the paste layer
1: Press molding by roller press to 1.3
By doing so, the negative electrode layer containing the hydrogen storage alloy
It has a structure supported on both sides, and the thickness ratio of the negative electrode layer is 1:
Four 1.3 negative electrodes for the outermost layer were prepared. Further, a negative electrode layer was formed in the same manner as in Example 1.
Six negative electrodes having a thickness ratio of 1: 1 were produced. Example 1
Each of the positive electrodes obtained in the same manner as in
Foreskin with a separator, and alternately overlap this with each negative electrode.
And the negative electrode is arranged in the outermost layer.
The negative electrode layer on the side is 1.3 times thicker than the outer negative electrode layer.
Two electrode groups were produced. As in Embodiment 1 using such an electrode group
Assemble 2-cell nickel-metal hydride rechargeable batteries
I was (Example 3) <Preparation of negative electrode> A paste similar to that of Example 1 was prepared, and
Apply the paste to one side of the punched metal current collector
Apply to a thickness of 0.7mm and apply a 1.0mm thickness on the other side
It was then applied and dried. Then, the thickness ratio of the paste layer
1: Press molding by roller press to 1.4
By doing so, the negative electrode layer containing the hydrogen storage alloy
It has a structure supported on both sides, and the thickness ratio of the negative electrode layer is 1:
Four negative electrodes for the outermost layer of 1.4 were produced. The negative electrode layer was formed in the same manner as in Example 1.
Six negative electrodes having a thickness ratio of 1: 1 were produced. Example 1
Each of the positive electrodes obtained in the same manner as in
Foreskin with a separator, and alternately overlap this with each negative electrode.
And the negative electrode is arranged in the outermost layer.
Side negative electrode layer is 1.4 times thicker than the outer negative electrode layer.
Two electrode groups were produced. As in Embodiment 1 using such an electrode group
Assemble 2-cell nickel-metal hydride rechargeable batteries
I was (Example 4) <Preparation of negative electrode> A paste similar to that of Example 1 was prepared, and
Apply the paste to one side of the punched metal current collector
Apply to 0.7mm thickness, 1.1mm thickness on the other side
It was then applied and dried. Then, the thickness ratio of the paste layer
1: Press forming by roller press to 1.5
By doing so, the negative electrode layer containing the hydrogen storage alloy
It has a structure supported on both sides, and the thickness ratio of the negative electrode layer is 1:
Four negative electrodes for the outermost layer of 1.5 were produced. The negative electrode layer was formed in the same manner as in Example 1.
Six negative electrodes having a thickness ratio of 1: 1 were produced. Example 1
Each of the positive electrodes obtained in the same manner as in
Foreskin with a separator, and alternately overlap this with each negative electrode.
And the negative electrode is arranged in the outermost layer.
Side negative electrode layer is 1.5 times thicker than the outer negative electrode layer.
Two electrode groups were produced. As in the first embodiment using such an electrode group
Assemble 2-cell nickel-metal hydride rechargeable batteries
I was (Comparative Example) Thickness ratio of negative electrode layer in the same manner as in Example 1.
10 negative electrodes having a ratio of 1: 1 were produced. Each positive electrode obtained in the same manner as in Example 1 was used.
The foreskin was wrapped with the same bag-shaped separator as in Example 1, and
The negative electrode is placed on the outermost layer by alternately overlapping the electrodes.
The thickness of the inner and outer negative electrode layers of this negative electrode
Two electrode groups having the same structure were produced. As in Embodiment 1 using such an electrode group
Assemble 2-cell nickel-metal hydride rechargeable batteries
I was (Reference example) <Preparation of negative electrode> A paste similar to that of Example 1 was prepared, and
Apply the paste to one side of the punched metal current collector
Apply 0.7mm thickness and 1.2mm thickness on the other side
It was then applied and dried. Then, the thickness ratio of the paste layer
1: Press forming by roller press to 1.6
By doing so, the negative electrode layer containing the hydrogen storage alloy
It has a structure supported on both sides, and the thickness ratio of the negative electrode layer is 1:
Four negative electrodes for the outermost layer of 1.6 were produced. The negative electrode layer was formed in the same manner as in Example 1.
Six negative electrodes having a thickness ratio of 1: 1 were produced. Example 1
Each of the positive electrodes obtained in the same manner as in
Foreskin with a separator, and alternately overlap this with each negative electrode.
And the negative electrode is arranged in the outermost layer.
Side negative electrode layer is 1.6 times thicker than the outer negative electrode layer.
Two electrode groups were produced. As in Embodiment 1 using such an electrode group
Assemble 2-cell nickel-metal hydride rechargeable batteries
I was Secondary of the obtained Examples 1 to 4, Comparative Example and Reference Example
The battery was charged and discharged for the first time, and then charged at 150 mA at 1 CmA.
% Charge, the battery voltage reaches 1.0 V at 1 CmA
The battery was subjected to a charge / discharge cycle in which the battery was discharged until the power was discharged. Every cycle
At 1CmA until the battery voltage reaches 1.0V
Calculate the discharge capacity between the first cycle and the 200th cycle
Table 1 shows the discharge capacities of the circles. In addition, the charge / discharge cycle
At the first and 200th cycle
Circuit voltage at the middle of the discharge time until the pressure reaches 1.0V
Pressure (CV) measurement, 1st cycle and 200th cycle
After the battery voltage of the battery reaches 1.0 V, the AC (1 kHz)
Measure the resistance between liquids, the first cycle and 200 cycles
Table 1 also shows the eye closing voltage and liquid junction resistance. Further, in Examples 1-4, Comparative Examples and Reference Examples
The internal pressure of the secondary battery was measured. Measurement of battery internal pressure
Each battery is stored in the container of the pressure measuring device shown in Fig. 2.
I went. That is, each battery internal pressure measuring device is made of acrylic
Battery comprising a resin case body 21 and a cap 22
Provide a case. At the center of the case body 21, A
Has the same inner diameter and height as the metal container for A-size batteries
A space 23 is formed. Inside the space 23
Houses the secondary battery 24. The secondary battery
24 has a sealing plate attached to the upper end of the bottomed cylindrical container.
It is open without being. On the case body 21,
The cap 22 is inserted through the packing 25 and the O-ring 26
And airtightly fixed by bolts 27 and nuts 28
ing. A pressure detector 29 is mounted on the cap 22.
It is attached. From the negative electrode lead 30 from the negative electrode and the positive electrode
The positive lead 31 of the packing 25 and the O-ring
26. An embodiment using such a battery internal pressure measuring device will be described.
1 to 4, 1 CmA for the secondary batteries of Comparative Example and Reference Example
After 150% charge at 1 CmA, the battery voltage is 1.0
V in each cycle in a charge / discharge cycle
The internal pressure of the battery during charging for each vehicle was measured.
The results of the 00th cycle are shown in Table 1 below. In addition, one size
Measure the start time of battery pressure increase at the 200th cycle and the 200th cycle.
And the results are shown in Table 1 below. [0041] [Table 1] As is clear from Table 1, the outermost layer of the electrode group
The inner negative electrode layer of the negative electrode located at
The secondary batteries of Examples 1 to 4 which are 1.1 to 1.5 times thicker than the secondary batteries
Are the secondary battery and the inner side of the comparative example in which the thickness ratio of the negative electrode layer is equal.
Of the reference example in which the negative electrode layer is 1.6 times thicker than the outer negative electrode layer.
Suppresses internal pressure rise associated with charge / discharge cycles compared to secondary batteries
Liquid resistance is low even after 200 cycles,
High capacity retention rate and closed circuit voltage retention rate after 200 cycles
I understand that [0043] As described in detail above, according to the present invention,
Long life with reduced internal pressure rise due to progress of discharge cycle
A square alkaline secondary battery can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view showing a prismatic alkaline secondary battery according to the present invention. FIG. 2 is a sectional view showing a battery internal pressure measuring device for measuring the internal pressure of the prismatic nickel-metal hydride secondary batteries of Examples 1 to 4 of the present invention. [Description of Signs] 1 ... Container, 2 ... Electrode group, 3 ... Positive electrode, 4 ... Negative electrode, 5 ... Separator, 7 ... Sealing plate.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01M 10/28 H01M 4/24

Claims (1)

(57) [Claims] 1. A bottomed rectangular tube-shaped container also serving as a negative electrode terminal.
When, The positive and negative electrodes are housed in the container, and a separator is
InterveningSo that the outermost layer is the negative electrodeAlternately
And an electrode group produced by An alkaline electrolyte contained in the container, A sealing member disposed at an opening of the container.Corner
Type alkaline secondary battery, In the negative electrode, a negative electrode layer containing a negative electrode active material is provided on both surfaces of a current collector.
Having a supported structure, Negative electrode located in the outermost layerso
Indicates that the negative electrode layer located inside is
1.1 to 1.5 times thickerNegative electrode other than the outermost negative electrode
Is the thickness of the inner negative electrode layer and the outer negative electrode layer.
Are equalA prismatic alkaline secondary battery characterized by the above-mentioned.