JPH03744B2 - - Google Patents
Info
- Publication number
- JPH03744B2 JPH03744B2 JP59122379A JP12237984A JPH03744B2 JP H03744 B2 JPH03744 B2 JP H03744B2 JP 59122379 A JP59122379 A JP 59122379A JP 12237984 A JP12237984 A JP 12237984A JP H03744 B2 JPH03744 B2 JP H03744B2
- Authority
- JP
- Japan
- Prior art keywords
- cadmium
- nickel
- hydroxide
- metal
- positive electrode
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 229910052751 metal Inorganic materials 0.000 claims description 37
- 239000002184 metal Substances 0.000 claims description 37
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 29
- BDOSMKKIYDKNTQ-UHFFFAOYSA-N cadmium atom Chemical compound [Cd] BDOSMKKIYDKNTQ-UHFFFAOYSA-N 0.000 claims description 24
- BFDHFSHZJLFAMC-UHFFFAOYSA-L nickel(ii) hydroxide Chemical compound [OH-].[OH-].[Ni+2] BFDHFSHZJLFAMC-UHFFFAOYSA-L 0.000 claims description 24
- PLLZRTNVEXYBNA-UHFFFAOYSA-L cadmium hydroxide Chemical compound [OH-].[OH-].[Cd+2] PLLZRTNVEXYBNA-UHFFFAOYSA-L 0.000 claims description 21
- 239000011149 active material Substances 0.000 claims description 20
- 229910052793 cadmium Inorganic materials 0.000 claims description 20
- 229910052759 nickel Inorganic materials 0.000 claims description 12
- 239000000758 substrate Substances 0.000 claims description 12
- OJIJEKBXJYRIBZ-UHFFFAOYSA-N cadmium nickel Chemical compound [Ni].[Cd] OJIJEKBXJYRIBZ-UHFFFAOYSA-N 0.000 claims description 6
- 238000003860 storage Methods 0.000 claims description 6
- 238000004519 manufacturing process Methods 0.000 claims description 4
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 claims description 3
- 238000007599 discharging Methods 0.000 description 15
- 239000007774 positive electrode material Substances 0.000 description 10
- 239000003792 electrolyte Substances 0.000 description 8
- 238000000034 method Methods 0.000 description 7
- WMFOQBRAJBCJND-UHFFFAOYSA-M Lithium hydroxide Chemical compound [Li+].[OH-] WMFOQBRAJBCJND-UHFFFAOYSA-M 0.000 description 6
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 6
- 230000007423 decrease Effects 0.000 description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- 230000000694 effects Effects 0.000 description 4
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 238000005054 agglomeration Methods 0.000 description 3
- 230000002776 aggregation Effects 0.000 description 3
- 230000006866 deterioration Effects 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 239000012670 alkaline solution Substances 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 239000006258 conductive agent Substances 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 238000005470 impregnation Methods 0.000 description 2
- 239000011148 porous material Substances 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- -1 In addition Substances 0.000 description 1
- 229910021503 Cobalt(II) hydroxide Inorganic materials 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 150000001661 cadmium Chemical class 0.000 description 1
- CXKCTMHTOKXKQT-UHFFFAOYSA-N cadmium oxide Inorganic materials [Cd]=O CXKCTMHTOKXKQT-UHFFFAOYSA-N 0.000 description 1
- CFEAAQFZALKQPA-UHFFFAOYSA-N cadmium(2+);oxygen(2-) Chemical compound [O-2].[Cd+2] CFEAAQFZALKQPA-UHFFFAOYSA-N 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- ASKVAEGIVYSGNY-UHFFFAOYSA-L cobalt(ii) hydroxide Chemical compound [OH-].[OH-].[Co+2] ASKVAEGIVYSGNY-UHFFFAOYSA-L 0.000 description 1
- 230000008602 contraction Effects 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 238000005868 electrolysis reaction Methods 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- 238000005429 filling process Methods 0.000 description 1
- 229910000480 nickel oxide Inorganic materials 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- GNRSAWUEBMWBQH-UHFFFAOYSA-N oxonickel Chemical compound [Ni]=O GNRSAWUEBMWBQH-UHFFFAOYSA-N 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/24—Electrodes for alkaline accumulators
- H01M4/32—Nickel oxide or hydroxide electrodes
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Battery Electrode And Active Subsutance (AREA)
Description
産業上の利用分野
本発明は、常閉型ニツケルカドミウム蓄電池の
製造法に関するものである。
従来例の構成とその問題点
常閉型ニツケルカドミウム蓄電池は、水酸化ニ
ツケルを主体とする正極と、水酸化カドミウムを
主体とする負極と、正、負両極を隔離するセパレ
ータと、電解液としての水酸化カリウム、水酸化
ナトリウム、水酸化リチウム等のアルカリ水溶液
とから構成されている。
負極としては、一般に焼結式、ペースト式等の
カドミウム極が用いられ、正極としては、多孔性
ニツケル焼結基板に、電解法、化学含浸法等の手
段によつて、正極活物質となる水酸化ニツケル、
水酸化コバルト等を充填したものが用いられてい
る。また最近ではスポンジ状の金属ニツケル基板
に、水酸化ニツケルを主体とした活物質ペースト
を充填した、高容量を有するニツケル正極も提案
されている。
従来の焼結式ニツケル正極の活物質充填工程
は、例えば化学含浸法のように含浸工程、アルカ
リ処理工程、水洗工程、乾燥工程等、数多くの工
程が必要であり、高容量の正極を得るためには、
これらの工程の数回に及ぶくり返えしが必要とな
り、非常に煩雑となつている。
一方、スポンジ状の金属ニツケル基板（90〜95
％の多孔度）を用いる方法は、孔径の大きいもの
が選択できることにより、基板中にペースト状の
活物質を直接充填でき、しかも充填後、加圧加工
を行なうだけの簡単な工程で、高容量を有するニ
ツケル正極の製造が可能になる。また正極板の特
性としては、容量面では、従来の焼結式の正極板
の単位体積当りの容量密度が350〜450ｍAh／cm3
程度であるのに対し、470〜520ｍAh／cm3程度の
高容量が得られ、大電流での放電特性も、焼結式
のものと同等の性能が得られる。
しかし、従来のスポンジ状の金属ニツケル基板
を用いる正極（以下スポンジメタル正極という）
は、焼結式ニツケル正極に比べ、その基板の物理
的強度が弱く、充電、放電のくり返しによつて、
極板のふくれを生じ、正、負極間に設置されたセ
パレータを圧縮し、充放電特性に大きく寄与する
セパレータ中の電解液を押し出して、放電特性を
劣化させる傾向が焼結式正極に比べて大きかつ
た。すなわち、充放電サイクル寿命は、焼結式に
比べ若干劣つているという欠点があつた。
この欠点を改良するために、正極活物質中に水
酸化カドミウムを添加する方法（特開昭59−
33758号）も提案されているが、スポンジ状の金
属ニツケル基板への活物質充填は、水酸化ニツケ
ルを主体とする活物質を水等でペースト状とした
もので行なうため、水酸化カドミウムを添加した
場合は、その凝集効果により充填が困難となるこ
と、また、添加する水酸化カドミウムの体積分だ
け、水酸化ニツケル活物質の充填量が減少し、極
板の単位体積当りの容量が減少すること、さらに
また、カドミウム塩から化学的手段によつて製造
された水酸化カドミウムを使用する場合には、そ
の水酸化カドミウムが電気化学的反応性に乏しい
ため、耐逆充電性向上への寄与が少ないという問
題があつた。
発明の目的
本発明は、上記のような水酸化カドミウムの問
題点を改良し、スポンジメタル正極の充電放電の
くり返しにおけるふくれと、それに起因する充放
電特性の劣化を改善することを目的としたもので
ある。
発明の構成
本発明は、スポンジ状の金属ニツケル基板に、
正極活物質としての水酸化ニツケルを主体とし、
これに導電剤としての金属ニツケル粉末、水酸化
ニツケル活物質の利用率を高めるための金属コバ
ルト粉末、及び充放電サイクル寿命特性向上のた
めの金属カドミウムを水酸化ニツケルに対する重
量比率で、１〜10％添加した構成の活物質ペース
トを充填し、この電極を正極に用い電池組立後の
充電により前記活物質中の金属カドミウムを水酸
化カドミウムに変化させることを特徴とする常閉
型ニツケルカドミウム蓄電池の製造法である。
以下に本発明の原理を説明する。
常閉型ニツケルカドミウム蓄電池において、充
電、放電特性を維持させるためには、正極、負極
及びその間に設置されたセパレータ内に、充放電
反応に寄与するアルカリ電解液が適度に分布して
いなければならない。
充放電のくり返しによる充放電特性の劣化、す
なわち充放電サイクル寿命劣化の大きな原因とし
ては、充放電のくり返しによる電解液分布の不均
一化がある。
正極、負極の両活物質は、それぞれ充電時、放
電時において異つた体積を有するため、両極、特
に正極は充電放電のくり返しによつて膨張、収縮
をくり返えししだいに電極全体が膨張する傾向が
ある。
このようにして膨張した正極板は、セパレータ
を圧縮し、セパレータ中に分布していた電解液を
押し出して電解液の分布は不均一となり、電池の
充電、放電特性が劣化する。
このような傾向は、スポンジ状金属ニツケル基
板などのようにその基板自身の強度が弱いもの、
あるいは活物質密度、容量密度の高い極板ほど大
きくなりやすい。つまり、単位体積あたりの放電
容量が大きいほどこの膨張傾向が大きくなる。
また、充放電のくり返えしを行なう雰囲気温度
を見ると、正極活物質が深い充電を受けやすい
（充電容量も大きくなる）低温側で、その傾向が
特に大きくなる。
これは、正極活物質の水酸化ニツケルの充電受
け入れ性の温度差によるもので、常温では水酸化
ニツケル活物質の理論容量に対し、90〜95％の活
物質が充放電反応に寄与するが、低温では水酸化
ニツケルが、一般に高次の酸化状態まで充電さ
れ、通常の理論容量以上の値を示す。
このように低温で深い充電、放電を受けた水酸
化ニツケルの膨張、収縮は大きく、充電放電サイ
クル時の正極の膨張を促進する。
スポンジメタル正極の充放電サイクル寿命特性
は、常温あるいは高温側では、従来の焼結式正極
と同等の長寿命を有するが、低温においては焼結
式に比べ若干劣つていた。
このような問題点を改良するために、水酸化カ
ドミウムを活物質中に添加する方法が提案されて
いるが、水酸化カドミウムの添加の場合には、先
に述べた通り、凝集効果による充填の難しさ、水
酸化カドミウムの体積分の容量低下等の問題があ
る。そこで本発明者らは、正極活物質中に金属カ
ドミウム粉末を添加し、電池組立後の充電により
前記金属カドミウムを電気化学的に酸化させて水
酸化カドミウムとする方法を試みた。その結果、
この方法により、低温側での充電の受入れ性が抑
制されるとともに充放電時の正極のふくれも低減
されて、サイクル寿命特性が大幅に改善されるこ
とを見い出した。また、金属カドミウム粉末は、
導電剤として使用している金属ニツケル粉末と同
様な性質のものであるため、水酸化カドミウムの
場合のような凝集効果もなく充填が容量である。
また、１モル当りの体積も、水酸化カドミウムに
比べ約45％と小さく、添加による水酸化ニツケル
量の減少のための容量密度低下も少ない。また、
電池組立後の充電時に水酸化カドミウムへ変化さ
せる際、金属カドミウムは体積膨張をおこしつ
つ、極板内の空孔部へ均一に分布して行くこと
と、電気化学的に生成した水酸化カドミウムが活
性であるために、添加量も水酸化カドミウム添加
の場合よりも少量で足りるという利点がある。
実施例の説明
以下実施例によつて、本発明を詳細に説明す
る。
正極基板としては、多孔度95％を有するスポン
ジ状の金属ニツケルを用い、正極活物質として
は、水酸化ニツケル、金属コバルト紛末、金属ニ
ツケル紛末及び金属カドミウムの混合物を水又は
水と少量の例えばCMCからなる結着剤を用いて
構成したペーストを使用した。
次表は、本実施例において検討した活物質組成
の比率を重量比率で示したものである。
INDUSTRIAL APPLICATION FIELD The present invention relates to a method for manufacturing a normally closed nickel cadmium storage battery. Conventional structure and problems A normally closed nickel-cadmium storage battery consists of a positive electrode mainly made of nickel hydroxide, a negative electrode mainly made of cadmium hydroxide, a separator that separates the positive and negative electrodes, and an electrolyte as an electrolyte. It is composed of aqueous alkaline solutions such as potassium hydroxide, sodium hydroxide, and lithium hydroxide. As the negative electrode, a sintered or paste type cadmium electrode is generally used, and as the positive electrode, water, which becomes the positive electrode active material, is added to a porous sintered nickel substrate by means such as electrolysis or chemical impregnation. nickel oxide,
Those filled with cobalt hydroxide or the like are used. Recently, a high-capacity nickel positive electrode has also been proposed, in which a sponge-like metallic nickel substrate is filled with an active material paste mainly composed of nickel hydroxide. The conventional active material filling process for sintered nickel positive electrodes requires many steps, such as chemical impregnation, an alkali treatment process, a water washing process, and a drying process, to obtain a high-capacity positive electrode. for,
It is necessary to repeat these steps several times, making it extremely complicated. On the other hand, a sponge-like metal nickel substrate (90~95
% porosity) allows selection of large pore diameters, which allows paste-like active material to be directly filled into the substrate.Furthermore, it is a simple process of pressurizing after filling, and can achieve high capacity. It becomes possible to manufacture a nickel positive electrode with In addition, regarding the characteristics of the positive electrode plate, in terms of capacity, the capacity density per unit volume of the conventional sintered positive electrode plate is 350 to 450 mAh/cm 3
In contrast, a high capacity of about 470 to 520 mAh/cm 3 can be obtained, and discharge characteristics at large currents are equivalent to those of the sintered type. However, the conventional positive electrode using a sponge-like metal nickel substrate (hereinafter referred to as a sponge metal positive electrode)
The physical strength of the substrate is weaker than that of sintered nickel positive electrodes, and the repeated charging and discharging
Compared to sintered positive electrodes, the electrode plates tend to bulge, compress the separator installed between the positive and negative electrodes, push out the electrolyte in the separator that greatly contributes to charge and discharge characteristics, and deteriorate discharge characteristics. It was big. That is, the charge/discharge cycle life was slightly inferior to that of the sintered type. In order to improve this drawback, a method of adding cadmium hydroxide to the positive electrode active material (Japanese Unexamined Patent Publication No. 59-1999)
No. 33758) has also been proposed, but the filling of the active material into the sponge-like metallic nickel substrate is done by making a paste of the active material, which is mainly nickel hydroxide, with water, etc., so cadmium hydroxide is added. If this happens, the agglomeration effect will make filling difficult, and the amount of nickel hydroxide active material packed will decrease by the volume of cadmium hydroxide added, reducing the capacity per unit volume of the electrode plate. Furthermore, when using cadmium hydroxide produced from cadmium salt by chemical means, the cadmium hydroxide has poor electrochemical reactivity, so it cannot contribute to improving reverse charge resistance. There was a problem with the lack of it. Purpose of the Invention The present invention aims to improve the problems of cadmium hydroxide as described above, and to improve the blistering caused by repeated charging and discharging of sponge metal positive electrodes and the deterioration of charging and discharging characteristics caused by this. It is. Structure of the Invention The present invention provides a sponge-like metal nickel substrate,
Mainly using nickel hydroxide as the positive electrode active material,
In addition, metal nickel powder as a conductive agent, metal cobalt powder to increase the utilization rate of the nickel hydroxide active material, and metal cadmium to improve charge/discharge cycle life characteristics are added at a weight ratio of 1 to 10 to nickel hydroxide. A normally closed type nickel cadmium storage battery, characterized in that it is filled with an active material paste having an additive composition of 10%, and this electrode is used as a positive electrode, and the metal cadmium in the active material is changed into cadmium hydroxide by charging after battery assembly. It is a manufacturing method. The principle of the present invention will be explained below. In order to maintain the charging and discharging characteristics of a normally closed nickel cadmium storage battery, an alkaline electrolyte that contributes to charge and discharge reactions must be appropriately distributed within the positive and negative electrodes and the separator installed between them. . A major cause of deterioration of charge-discharge characteristics due to repeated charging and discharging, that is, deterioration of charge-discharge cycle life, is non-uniformity of electrolyte distribution due to repeated charging and discharging. Since the active materials of the positive and negative electrodes have different volumes during charging and discharging, both electrodes, especially the positive electrode, expand and contract repeatedly due to repeated charging and discharging, and the entire electrode gradually expands. Tend. The positive electrode plate expanded in this way compresses the separator and pushes out the electrolyte distributed in the separator, resulting in uneven distribution of the electrolyte and deteriorating the charging and discharging characteristics of the battery. This tendency occurs when the substrate itself is weak, such as a spongy metal nickel substrate,
Alternatively, the electrode plate with higher active material density and higher capacity density tends to be larger. In other words, the greater the discharge capacity per unit volume, the greater this expansion tendency becomes. Furthermore, when looking at the ambient temperature at which repeated charging and discharging are performed, the tendency is particularly strong at low temperatures where the positive electrode active material is more likely to undergo deep charging (the charging capacity is also increased). This is due to the temperature difference in the charge acceptance of nickel hydroxide, the positive electrode active material.At room temperature, 90 to 95% of the active material contributes to the charge/discharge reaction relative to the theoretical capacity of the nickel hydroxide active material. At low temperatures, nickel hydroxide is generally charged to a higher oxidation state, exhibiting values above its normal theoretical capacity. As described above, nickel hydroxide undergoes deep charging and discharging at low temperatures and undergoes significant expansion and contraction, promoting expansion of the positive electrode during charging and discharging cycles. The charge/discharge cycle life characteristics of the sponge metal positive electrode were as long as those of conventional sintered positive electrodes at room temperature or high temperatures, but were slightly inferior to those of the sintered type at low temperatures. In order to improve these problems, a method of adding cadmium hydroxide to the active material has been proposed, but as mentioned above, when adding cadmium hydroxide, it is difficult to fill the active material due to the agglomeration effect. There are problems such as difficulty and a decrease in capacity by the volume of cadmium hydroxide. Therefore, the present inventors attempted a method of adding metal cadmium powder to the positive electrode active material and electrochemically oxidizing the metal cadmium to cadmium hydroxide by charging after battery assembly. the result,
It has been found that this method suppresses charging acceptability at low temperatures, reduces blistering of the positive electrode during charging and discharging, and significantly improves cycle life characteristics. In addition, metal cadmium powder is
Since it has properties similar to the metal nickel powder used as a conductive agent, it has no agglomeration effect as in the case of cadmium hydroxide and can be filled with a high capacity.
Furthermore, the volume per mole is about 45% smaller than that of cadmium hydroxide, and the decrease in capacity density due to the reduction in the amount of nickel hydroxide caused by addition is small. Also,
When changing into cadmium hydroxide during charging after battery assembly, metal cadmium expands in volume and is distributed uniformly into the pores in the electrode plate, and the electrochemically generated cadmium hydroxide Since it is active, it has the advantage that it only needs to be added in a smaller amount than when cadmium hydroxide is added. DESCRIPTION OF EMBODIMENTS The present invention will be explained in detail with reference to Examples below. Sponge-like nickel metal with a porosity of 95% is used as the positive electrode substrate, and a mixture of nickel hydroxide, cobalt metal powder, nickel metal powder, and cadmium metal is used as the positive electrode active material in water or in a small amount with water. For example, a paste constructed using a binder consisting of CMC was used. The following table shows the ratios of the active material compositions examined in this example in terms of weight ratios.
【表】
なお負極としては、通常のペースト式カドミウ
ム極を使用した。また電解液は一般に使用されて
いる水酸化カリウムと水酸化リチウムとの混合水
溶液を使用した。
上記正極、負極を用い、1500ｍAh相当の常閉
型ニツケルカドミウム蓄電池を試作し、電池容量
試験、及び充放電サイクル試験を行つた。正極活
物質中の金属カドミウムは、アルカリ液中で長期
間放置すると、水酸化カドミウム、酸化カドミウ
ム等に変化する。本発明では金属カドミウムを電
気化学的に酸化させて水酸化カドミウムに変化さ
せる必要があるので、電池組立後の充電は、組立
後１日以内に行つた。
電池容量試験は、通常の方法で行ない、20℃の
雰囲気温度で、150ｍＡで16時間充電し、300ｍＡ
で放電したときの電池容量を求めた。
この電池容量と、正極板体積から求めた正極板
単位体積当りの容量密度と、正極活物質中の水酸
化ニツケルに対する金属カドミウムの重量比率と
の関係を第１図に示す。
サイクル寿命特性向上の目的で添加する金属カ
ドミウムは、電池容量には寄与しない。従つて第
１図に示すように、正極板中の金属カドミウム比
率が増加するに従つて、正極板の容量密度は低下
し、その比率が10％以上になると、正極板の容量
密度が従来の焼結式正極のレベルに近づき、高容
量を指向したスポンジメタル正極の特長が減少す
る。
第２図は、低温（０℃）での充放電サイクル寿
命特性の結果である。
充放電サイクルの条件は、０℃の雰囲気で、
500ｍＡの電流により４時間30分放電を行ない、
1500ｍＡ相当の定抵抗で75分放電を行つた。
また図中の放電時間は、電池電圧が1.0Vとな
るまでの時間とした。
図に示すように、正極活物質に金属カドミウム
を全く添加しない場合ａは、放電時間が充放電回
数とともに徐々に増大し、その後急速に劣化する
ことがわかる。これは先に述べたように、充放電
回数の進行とともに、充電の受け入れ性が向上
し、従つて放電時間も増大して極板のふくれを生
じ、その後電池特性が急速に劣化したものと思わ
れる。
金属カドミウムの添加量が、水酸化ニツケルに
対して0.5重量％の場合ｂでは、まだ上記のよう
な傾向が認められる。水酸化ニツケルに対する添
加量が１重量％の場合ｃ及び３重量％の場合ｄは
放電時間のばらつきが少ない。従つて、第２図か
らわかるように水酸化カドミウムの最低必要量
は、重量比率で水酸化ニツケルの１％以上であ
る。
また、金属カドミウムの添加量が５、10、15重
量％の場合にも、１、３重量％の場合と同様な結
果を得た。しかし、その比率が10重量％を超える
と、先に述べたように極板容量の低下が問題とな
るので、金属カドミウムの添加比率としては水酸
化ニツケルに対して重量比で１〜10％が適当と思
われる。
発明の効果
以上のように、スポンジメタル正極の活物質中
に、金属カドミウムを水酸化ニツケルに対して重
量比率で１〜10％添加し、これを電池組立後の充
電時に電気化学的に水酸化カドミウムに変化させ
ることにより、高容量密度を維持し、かつ充放電
サイクル寿命特性の大幅な改善が可能となる。[Table] A normal paste-type cadmium electrode was used as the negative electrode. The electrolyte used was a commonly used mixed aqueous solution of potassium hydroxide and lithium hydroxide. Using the above positive and negative electrodes, a normally closed nickel cadmium storage battery with a capacity of 1500 mAh was prototyped, and a battery capacity test and a charge/discharge cycle test were conducted. When the metal cadmium in the positive electrode active material is left in an alkaline solution for a long period of time, it changes into cadmium hydroxide, cadmium oxide, etc. In the present invention, since it is necessary to electrochemically oxidize metal cadmium and change it into cadmium hydroxide, charging after assembly of the battery was performed within one day after assembly. The battery capacity test was carried out in the usual way, charging at 150mA for 16 hours at an ambient temperature of 20℃, then charging at 300mA.
The battery capacity when discharged was determined. FIG. 1 shows the relationship between this battery capacity, the capacity density per unit volume of the positive electrode plate determined from the volume of the positive electrode plate, and the weight ratio of metal cadmium to nickel hydroxide in the positive electrode active material. Metal cadmium added for the purpose of improving cycle life characteristics does not contribute to battery capacity. Therefore, as shown in Figure 1, as the metal cadmium ratio in the positive electrode plate increases, the capacity density of the positive electrode plate decreases, and when the ratio exceeds 10%, the capacity density of the positive electrode plate becomes lower than the conventional one. It approaches the level of a sintered positive electrode, and the characteristics of the sponge metal positive electrode, which is oriented toward high capacity, are reduced. FIG. 2 shows the results of charge/discharge cycle life characteristics at low temperature (0° C.). The charge/discharge cycle conditions are in an atmosphere of 0°C.
Discharge with a current of 500mA for 4 hours and 30 minutes,
Discharge was performed for 75 minutes at a constant resistance equivalent to 1500mA. Further, the discharge time in the figure was the time until the battery voltage reached 1.0V. As shown in the figure, it can be seen that in the case a in which no metal cadmium is added to the positive electrode active material, the discharge time gradually increases with the number of charges and discharges, and then rapidly deteriorates. This is probably because, as mentioned earlier, as the number of charging and discharging cycles progresses, the receptivity to charging improves, and the discharging time also increases, causing the electrode plates to bulge, after which the battery characteristics rapidly deteriorate. It will be done. In case b, where the amount of metal cadmium added is 0.5% by weight based on nickel hydroxide, the above-mentioned tendency is still observed. When the amount added to nickel hydroxide is 1% by weight, c and d, when it is 3% by weight, there is little variation in discharge time. Therefore, as can be seen from FIG. 2, the minimum required amount of cadmium hydroxide is at least 1% by weight of nickel hydroxide. Further, similar results were obtained when the amount of metal cadmium added was 5, 10, and 15% by weight as in the case of 1 and 3% by weight. However, if the ratio exceeds 10% by weight, a decrease in electrode plate capacity becomes a problem as mentioned earlier, so the addition ratio of metal cadmium is 1 to 10% by weight relative to nickel hydroxide. Seems appropriate. Effects of the Invention As described above, metal cadmium is added to the active material of the sponge metal positive electrode in a weight ratio of 1 to 10% relative to nickel hydroxide, and this is electrochemically hydrated during charging after battery assembly. By changing to cadmium, it is possible to maintain high capacity density and significantly improve charge/discharge cycle life characteristics.
第１図は水酸化ニツケルに対する金属カドミウ
ムの添加比率と、正極容量密度との関係を示す
図、第２図は、水酸化ニツケルに対する金属カド
ミウムの添加比率と、充放電サイクル特性との関
係を示す図である。
Figure 1 shows the relationship between the addition ratio of metal cadmium to nickel hydroxide and the positive electrode capacity density, and Figure 2 shows the relationship between the addition ratio of metal cadmium to nickel hydroxide and charge/discharge cycle characteristics. It is a diagram.
Claims (1)
ツケルを主体とした活物質ペーストを充填した正
極を備え、前記活物質ペーストが、水酸化ニツケ
ルと金属ニツケル粉末と金属コバルト粉末と水酸
化ニツケルに対して、重量比率で１〜10％の金属
カドミウム粉末を含み、電池組立後の充電時に前
記活物質中の金属カドミウムを電気化学的に水酸
化カドミウムに変化させることを特徴とする密閉
型ニツケルカドミウム蓄電池の製造法。1 A sponge-like metal nickel substrate is equipped with a positive electrode filled with an active material paste mainly composed of nickel hydroxide, and the active material paste has a positive electrode with respect to nickel hydroxide, metal nickel powder, metal cobalt powder, and nickel hydroxide. , a sealed nickel-cadmium storage battery, which contains 1 to 10% by weight of metal cadmium powder, and which electrochemically changes the metal cadmium in the active material into cadmium hydroxide during charging after battery assembly. Manufacturing method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59122379A JPS612268A (en) | 1984-06-14 | 1984-06-14 | Manufacture of sealed nickel-cadmium battery |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59122379A JPS612268A (en) | 1984-06-14 | 1984-06-14 | Manufacture of sealed nickel-cadmium battery |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS612268A JPS612268A (en) | 1986-01-08 |
| JPH03744B2 true JPH03744B2 (en) | 1991-01-08 |
Family
ID=14834370
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP59122379A Granted JPS612268A (en) | 1984-06-14 | 1984-06-14 | Manufacture of sealed nickel-cadmium battery |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS612268A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2959885B2 (en) * | 1991-08-26 | 1999-10-06 | トヨタ自動車株式会社 | Temperature control device for electric melting furnace |
-
1984
- 1984-06-14 JP JP59122379A patent/JPS612268A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS612268A (en) | 1986-01-08 |
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| EXPY | Cancellation because of completion of term |