JPS6097560A - Sealed type alkaline storage battery - Google Patents

Abstract

PURPOSE:To keep good charge-discharge performance for a long time, and prevent gas evolution and leakage to the outside of a battery by using potassium hydroxide solution having a specified range of specific gravity as electrolyte. CONSTITUTION:Potassium hydroxide solution having sp.gr. 1.32-1.40 (at 20 deg.C), which is higher concentration compared with conventional one, is used as electrolyte of sealed type alkaline storage battery having non-sintered nickel electrode prepared by adding carbon as conductor and which absorbs gas by Neuman mechanism. Addition of 10g/l or more of lithium hydroxide is preferable. Optimum range of specific gravity of potassium hydroxide is 1.34-1.38. Addition of lithium hydroxide from 10g/l to saturation is effective to increase utilization rate of nickel electrode.

Description

【発明の詳細な説明】 産業上の利用分野 本発明は、活物質合剤中に炭素粉末を有する非焼結式ニ
ッケル極を備えたとくにニッケルーカドミウム電池に係
シ、その他の系、ニッケルー亜鉛系。DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates particularly to nickel-cadmium batteries, other systems, nickel-zinc batteries with non-sintered nickel electrodes having carbon powder in the active material mixture. system.

ニッケルー水素系などの密閉形アルカリ蓄電池の改良に
も関する。It also concerns the improvement of sealed alkaline storage batteries such as nickel-metal hydride batteries.

従来例の構成とその問題点 密閉形アルカリ蓄電池は、保守が容易で、放電特性にす
ぐれ、また寿命も長く過充電に強いなどの特長を有して
いるので、ポータプル機器用を中心に広く実用化が進ん
できた。Conventional configuration and its problems Sealed alkaline storage batteries are easy to maintain, have excellent discharge characteristics, have a long life, and are resistant to overcharging, so they are widely used in portable devices and other applications. has progressed.

この電池に使われているのは、正極としては、ニッケル
が最も多く、一部に銀が用いられている。Nickel is the most commonly used positive electrode in this battery, with some silver also being used.

一方の負極には、カドミウムが最も多く、亜鉛。The negative electrode, on the other hand, contains the most cadmium and zinc.

水素なども部分的に使われている。Hydrogen is also partially used.

ニッケル電極は、とくにアルカリ水溶液中で安定であり
、充放電の可逆性にも優れていて長寿命が得られている
。さらに利用率の点でもすぐれている。このような特徴
は、焼結式ニッケル極ではとくによく発揮できるので、
密閉形の系では、この焼結式ニッケル極が主流を占めて
いる。Nickel electrodes are particularly stable in alkaline aqueous solutions, have excellent charge/discharge reversibility, and have a long life. It also has an excellent utilization rate. These characteristics are particularly well exhibited in sintered nickel electrodes, so
In closed systems, this sintered nickel electrode is the mainstream.

焼結式ニッケル極は、微孔を有する焼結体に、ニッケル
塩溶液を加えてこれを活物質に転化する工程で得られる
ので、電池特性の点では優れているが、他の構造の電極
に比べると高価である欠点を有している。Sintered nickel electrodes are obtained by adding a nickel salt solution to a sintered body with micropores and converting it into an active material, so they have excellent battery characteristics, but electrodes with other structures It has the disadvantage of being more expensive than.

そこで、このような焼結式にかえて、活物質合剤をペー
スト状にして多孔性導電性の芯材に塗着したり充てんす
る非焼結式が研究対象として取上げられ、実用化がはか
られている。また、ペースＩ・の代りに粉末を加圧によ
り芯材に塗着する加圧式も同様の考え方で試みられてい
る方式である。Therefore, instead of such a sintering method, a non-sintering method in which the active material mixture is made into a paste and is applied or filled into a porous conductive core material has been studied, and practical application is in progress. It's getting messy. In addition, a pressurized method in which powder is applied to the core material under pressure instead of PACE I is a method that has been tried based on a similar concept.

この場合に、多孔性の芯材としては、スクリーン状、エ
キスバンドメタル、ノくンチングメタル彦どの二次元構
造のものが大量生産に適しているので最も安価である。In this case, the porous core material has a two-dimensional structure such as a screen, expanded metal, or punched metal, which is suitable for mass production and is therefore the cheapest.

したがってこれを芯材に用いて得られるニッケル電極は
、焼結式よりもかなり低廉になる。Therefore, the nickel electrode obtained using this as a core material is considerably cheaper than the sintered type.

このような非焼結式電極が、カドミウム極や亜鉛極など
では実用化されているが、ニッケル極については、多く
の提案があるにもかかわらず広くは実用化されていない
。その理由としては、ニッケルは、活物質になると、充
電状態、放電状態とＬすぐれた導電体ではない。したが
って導電剤を別に加える必要があり、その添加量には制
限力玉あることかまずあげられる。その他に、ニッケル
活物啜は１．充放電のくり返しにより体積変化を牛し、
電極の強度が低下する。これを抑制するために、結着剤
を多量に用いると活物質利用率２電圧ともに低下してし
まうことなどがあげられる。Such non-sintered electrodes have been put into practical use with cadmium electrodes, zinc electrodes, etc., but nickel electrodes have not been widely put into practical use despite many proposals. The reason for this is that nickel, when used as an active material, is not a good conductor in terms of charging and discharging states. Therefore, it is necessary to separately add a conductive agent, and there are some limitations on the amount of the conductive agent added. In addition, nickel active material slurry is 1. The volume changes due to repeated charging and discharging,
Electrode strength decreases. In order to suppress this, if a large amount of binder is used, both the active material utilization rate and the voltage will decrease.

それでも、この非焼結式電極では、とくにポケット式で
は広く用いられている、３導電剤として炭素粉末を用い
ることが、ニッケル活物質の利用率の向上と、比較的急
放電の条ｆ１下での放電電圧の低下の抑制に効果がある
ことがわかってきた。ところが、このように導電剤とし
て炭素粉末を加えた非焼結式ニッケル極を用いて、密閉
形のアルカリ蓄電池を構成し、いわゆるノイマン効果に
よる密閉化を期待して充放電をくり返すと、ニッケル極
として焼結式を用いた電池に比べて少ないサイクル数で
負極によるガスの吸収力が低下して漏液したり、放電電
圧が低下する現象が認められた。Nevertheless, in this non-sintered electrode, the use of carbon powder as a conductive agent, which is widely used especially in pocket type electrodes, improves the utilization rate of the nickel active material and under the relatively rapid discharge condition f1. It has been found that this method is effective in suppressing the decrease in discharge voltage. However, when a sealed alkaline storage battery is constructed using non-sintered nickel electrodes to which carbon powder is added as a conductive agent, and the battery is repeatedly charged and discharged with the expectation of sealing due to the so-called Neumann effect, the nickel Compared to batteries using sintered electrodes, the negative electrode's ability to absorb gas decreased with a smaller number of cycles, resulting in liquid leakage and a decrease in discharge voltage.

なお、この場合に、炭素粉末としては、活性炭でも黒鉛
でもこのような現象が認められた。In this case, this phenomenon was observed with both activated carbon and graphite as carbon powder.

発明の目的 本発明は、このように炭素を導電剤として加えた非焼結
式ニッケル極を備えた密閉形アルカリ蓄電池の充放電特
性を長期にわたって良好に維持せしめ、電池外へのガス
の発生や漏液を防止することを目的とし、この電極を用
いた密閉形アルカリ蓄電池の実用性を犬にすることにあ
る。Purpose of the Invention The present invention maintains good charging and discharging characteristics over a long period of time in a sealed alkaline storage battery equipped with a non-sintered nickel electrode to which carbon is added as a conductive agent, and prevents the generation of gas outside the battery. The purpose is to prevent leakage and to improve the practicality of sealed alkaline storage batteries using this electrode.

発明の構成 本発明は、炭素を導電剤として加えた非焼結式ニッケル
極を備え、ノイマン方式でガス吸収を可能にする密閉形
アルカリ蓄電池において、電解液として比重が１．３２
〜１．４０（２０℃）のように従来よりも高濃度の苛性
カリ水溶液を用いることを特命とし、好ましくは、これ
に水酸化リチウムを１ｏｙ／１以上の濃度で加えること
を特徴とするものである。Structure of the Invention The present invention provides a sealed alkaline storage battery that is equipped with a non-sintered nickel electrode to which carbon is added as a conductive agent and that enables gas absorption using the Neumann method.
The special purpose is to use a caustic potassium aqueous solution with a higher concentration than conventional ones, such as ~1.40 (20 ° C.), and preferably add lithium hydroxide to this at a concentration of 1 oy/1 or more. be.

さらに最適な苛性カリ水溶液の比重は、１．３４〜１．
３８の範囲である。寸だ水酸化リチウムについては、添
加すれば、それだけの効果があるので、１０？／１以上
、飽和までの任意の濃度をえらべば、とくにニッケル極
の利用率の向」二に有効である。Further, the optimum specific gravity of the caustic potassium aqueous solution is 1.34 to 1.
The range is 38. As for lithium hydroxide, if you add it, it will have that much effect, so 10? Choosing an arbitrary concentration from /1 to saturation is particularly effective in improving the utilization rate of the nickel electrode.

実施例の説明 性能比較のだめの電池として、単２形相当の円筒密閉形
ニック゛ルーカドミウム蓄電池を取り−１−げた。また
、ニッケル極としては２、ペースト式を具体例とし、ニ
ッケル活物質合剤に加える炭素粉末としては、導電性の
向上に有効なリン状黒鉛を加えた場合を例とした。DESCRIPTION OF EXAMPLES As a battery for performance comparison, a sealed cylindrical nickel cadmium storage battery equivalent to AA size was used. In addition, as a specific example of the nickel electrode, a paste type was used as an example, and as an example of the carbon powder added to the nickel active material mixture, phosphorous graphite, which is effective in improving conductivity, was added.

ニッケル正極を構成するためのペーストとじては、２０
０メツシユのふるいを通過する粒度の水酸化ニッケル１
Ｋｙと、カーボニルニッケル８０９、直径０．１５　ｍ
ｍ　、長さ５咽のアクリロニトリル−塩化ビニル共重合
体製の繊維を２５７．金属コバルト５０２、これにリン
状黒鉛１２０７を加えた。The paste for composing the nickel positive electrode is 20
Nickel hydroxide with a particle size that passes through a 0 mesh sieve 1
Ky and carbonyl nickel 809, diameter 0.15 m
A fiber made of acrylonitrile-vinyl chloride copolymer having a length of 5 mm and a length of 257. Metallic cobalt 502 and phosphorous graphite 1207 were added thereto.

カルホキツメチルセルロースの２．５重量係水溶液を１
　Ｋ９加えてペーストにした。また、結着剤としてポリ
エチレンの微粉末を４０７加えた。1 of a 2.5 weight aqueous solution of calhokitsum methyl cellulose
I added K9 and made it into a paste. Further, 407 g of fine polyethylene powder was added as a binder.

芯月には、厚さ０．１１ｍｍ、穴径２咽、穴中心間ピッ
チ２．５胴に開孔した鉄にニッケルメッキしたパンチン
グメタルを用いた。この芯材の両面に、上記ペーストを
塗着し、スリット間を通して乾燥後の厚さを１．４±０
．０５ｍｍ　にした。これを−辺が０．２　ｆｉ、高さ
が０．０８ｍｍの立方形の凸部を１閣間隔で有するいわ
ゆるエンボス加工した面を持つ６００鵡径のローラー間
に４回くり返し通して加圧した。電極の厚さは０．６８
±０．０２ｍｍとなり、電極は約１２％伸延した。For the core, a punched metal plated with nickel on iron was used, which had a thickness of 0.11 mm, a hole diameter of 2, and a hole center pitch of 2.5 mm. Apply the above paste to both sides of this core material and pass it between the slits to a thickness of 1.4±0 after drying.
．． 05mm. This was repeatedly passed between 600 mm diameter rollers with a so-called embossed surface having cubic convex portions of 0.2 fi sides and 0.08 mm height at intervals of one cabinet, and then pressed. . The thickness of the electrode is 0.68
±0.02 mm, and the electrode was approximately 12% elongated.

この電極を単２形相当の大きさに裁断した。この場合は
、幅３９爺で長さを２２０ｗＩ＋にした。これを公知の
カドミウム極とポリアミド不織布をセパレータとして組
合せて電池を構成した。この場合のカドミウム極として
は、酸化カドミウムを主材料とし、これにポリビニルア
ルコールのエチレングリコール溶液を加えてペースト状
にし、ニッケル極に用いたと同じ芯材に塗着後に乾燥し
て得られたものである。電極の厚さは０．６±０．０２
ｍｍ、長さは２６０朔とした。全酸化カドミウムから計
算でめた容量は約５８００ｍＡｈであり、正極容量の約
２．３倍とした。充電時での酸素ガス吸収能の向上と放
電時のカドミウム極での容量低下の防止に必要な部分充
電を行ない、Ａ群では、６７６ｍＡｈ、Ｂ群では１３５
０ｍＡｈ　、　Ｃ群では２０２２Ｏ２５の容量を有する
カドミウム極とした。This electrode was cut into a size equivalent to a AA size. In this case, the width was 39 mm and the length was 220 wI+. A battery was constructed by combining this with a known cadmium electrode and a polyamide nonwoven fabric as a separator. In this case, the cadmium electrode was obtained by using cadmium oxide as the main material, adding an ethylene glycol solution of polyvinyl alcohol to it, making it into a paste, applying it to the same core material used for the nickel electrode, and then drying it. be. Electrode thickness is 0.6±0.02
mm, and the length was 260 mm. The capacity calculated from total cadmium oxide was about 5800 mAh, which was about 2.3 times the positive electrode capacity. Partial charging is carried out necessary to improve oxygen gas absorption ability during charging and prevent capacity reduction at the cadmium electrode during discharging, resulting in 676 mAh for group A and 135 mAh for group B.
0 mAh, Group C had a cadmium electrode with a capacity of 2022O25.

次表に、各Ａ、Ｂ、Ｃを用いた電池の計算容量（正極律
則）、と用いた苛性カリ水溶液の比重を示す。なお、水
酸化リチウムは３ｏｔ／１．電解液量は６　、５ｃｃと
した。正極の計算容量は２．４１〜２．４ｓＡｈである
。The following table shows the calculated capacity (positive electrode rule) of batteries using each of A, B, and C and the specific gravity of the caustic potassium aqueous solution used. In addition, lithium hydroxide is 3ot/1. The amount of electrolyte was 6.5 cc. The calculated capacity of the positive electrode is 2.41-2.4 sAh.

（以　下　余　白） まず、初期性能については、正極と電解液比重が大きく
影響するので、八−１，Ｂ−１，Ｃ−１と同じ屋ではは
ソ同じ特性を示す。たとえば０，２Ｃでの利用率は、Ａ
−１、Ｂ−１、Ｃ−１ではほぼ９１％、以下高濃度にな
るほど利用率は向上し、八−５，Ｂ−５，Ｃ−５はほぼ
９４％、Ａ−１ｏ。(Margins below) First, regarding the initial performance, since the specific gravity of the positive electrode and the electrolyte have a large influence, the same properties as 8-1, B-1, and C-1 will show the same characteristics. For example, the utilization rate at 0.2C is A
-1, B-1, and C-1 are approximately 91%, and the utilization rate improves as the concentration increases, and 8-5, B-5, and C-5 are approximately 94%, and A-1o.

Ｂ−１０，Ｃ−１０では１ｏｏ％であった。このような
高利用率は、パンチングメタルのような二次元構造の芯
材を用いた非焼結式ニッケル極では従来では得らたてお
らず、この理由の大きな役割をはたしているのが炭素、
実施例ではリン状黒鉛の存在である。つまシ、リン状黒
鉛を加えずに、これと同じ重量比のニッケルを加えた場
合の利用率は、たとえば比重１．３２の苛性カリ水溶液
を用いた場合で７３係であった。In B-10 and C-10, it was 100%. Such a high utilization rate has not previously been achieved with non-sintered nickel electrodes that use a core material with a two-dimensional structure such as punched metal, and carbon plays a major role in this reason.
In the example, it is the presence of phosphorous graphite. The utilization rate when adding nickel at the same weight ratio without adding phosphorous graphite was, for example, 73 when using a caustic potassium aqueous solution with a specific gravity of 1.32.

このように水酸化ニッケルの導電性を向上させるだめに
炭素を加えることは、利用率の向上に極めて効果が大き
い。しかし、問題になるのは、これを用いた密閉形構造
で、負極のガス吸収に依存するいわゆるノイマン効果で
密閉化を可能にする実用的な電池の場合に、このような
炭素を含む非焼結式ニッケル極は、これを含まない非焼
結式電極や焼結式電極とは異なり、とくに負極の放電特
性が劣化してしまうことがわかった。また、正極も充電
効率が低下することが認められた。つまり表の各電池を
、４００　ｍＡで８時間の充電放電は９００　ｍＡで端
子電圧ｏ、ｓＶまでの条件で充放電をくり返したところ
、まず、５０サイクルまでに、Ｃ−１〜４では、化成時
の負極の化成容量が大きいので水素が発生し易く、その
ために水素発生電位に至って電解液の漏液が生じた。ま
た、Ａ−１〜４では、カドミウムの充電量が化成時にお
いて少ないだめに、カドミウムの容量低下をもたらし、
カドミウム極で容量が低下する現象が生じた。これに対
しでＢ−１〜Ｂ−４では、Ａ−１〜４．Ｃ−１〜４はど
には顕著な現象はなかっだが、１６０ザイクル程度で正
極の充電効率が極端に低下し、容量が低下した。なお、
これらのＡ、Ｂ、Ｃに認められた現象はいずれもＡ　４
　、３　、２　、１の順に顕著であった。これらに対し
て、とくにＡ、Ｂ。Adding carbon to improve the conductivity of nickel hydroxide is extremely effective in improving the utilization rate. However, the problem lies in the sealed structure using this type of battery, which can be sealed using the so-called Neumann effect that relies on gas absorption in the negative electrode. It has been found that, unlike non-sintered or sintered electrodes, the sintered nickel electrode deteriorates the discharge characteristics of the negative electrode in particular. It was also observed that the charging efficiency of the positive electrode also decreased. In other words, when each battery in the table was charged and discharged at 400 mA for 8 hours and then charged and discharged at 900 mA until the terminal voltage was o, sV, by 50 cycles, the chemical formation Since the formation capacity of the negative electrode was large at the time, hydrogen was easily generated, and as a result, the hydrogen generation potential was reached and leakage of the electrolyte occurred. In addition, in A-1 to A-4, the amount of charged cadmium during formation is small, resulting in a decrease in the capacity of cadmium,
A phenomenon occurred in which the capacity decreased at the cadmium electrode. On the other hand, in B-1 to B-4, A-1 to B-4. Although there was no noticeable phenomenon in C-1 to C-4, the charging efficiency of the positive electrode was extremely reduced after about 160 cycles, and the capacity was reduced. In addition,
All of the phenomena observed in A, B, and C are A4
, 3, 2, and 1 were most prominent in this order. For these, especially A and B.

ＣのＡ６〜屋９はすぐれていて、いずれもＡ　、　Ｂ。C's A6 to Ya9 are excellent, and both are A and B.

Ｃの煮１〜４に認められたような現象は、はとんどなく
、わずかにＡ−１〜４と同じ現象がＡ−５で５６０サイ
クル後に、まだ、Ｃ−１〜４と同じ現象がＣ−ｅｓ、Ｃ
−ｅでそれぞれ４４０サイクルと４８０サイクルで生じ
たのみである。The phenomenon observed in C-1 to C-4 is very rare, and even after 560 cycles in A-5, the same phenomenon as in A-1 to C-4 is still observed. is C-es, C
-e only occurred at 440 and 480 cycles, respectively.

すなわち、Ａ−６〜ａ、Ｂ−６〜ａ、Ｃ−ｅ〜８におい
ては、良好な充放電特性を維持し、プロサイクル以上を
確認することができた。なお、これ以上電解液の比重を
犬にするｊと、やで寿命が短かくなるのでＡ−１０、Ｂ
−１０、Ｃ−１０は好ましくない。That is, in A-6~a, B-6~a, and C-e~8, it was possible to maintain good charge/discharge characteristics and confirm procycle or higher. In addition, if the specific gravity of the electrolyte is made higher than this, the lifespan will be shortened, so A-10, B
-10 and C-10 are not preferred.

このような現象は、焼結式や、非焼結式でも炭素粉末を
用いない場合には認められず、これらの場合の電解液と
しての苛性カリの比重は、さらに低濃度の１．２２〜１
．３２の範囲で十分であった。Such a phenomenon is not observed in sintered or non-sintered systems that do not use carbon powder, and in these cases, the specific gravity of caustic potassium as an electrolyte is lower than that of 1.22 to 1.
．． A range of 32 was sufficient.

つまり、炭素による悪影響は、電解液の比重を犬にする
、つまり１．３２〜１．４０好ましくは１．３４〜１．
３８にすることにより抑制でき、利用率の向上をはかれ
る。In other words, the negative effect of carbon makes the specific gravity of the electrolyte dog, that is, 1.32-1.40, preferably 1.34-1.
By setting the number to 38, it can be suppressed and the utilization rate can be improved.

発明の効果 以上のように本発明の非焼結式ニッケル極を備えた密閉
形フルカリ電池においては、充放電特性を長期にわたっ
て良好に維持せしめ、電池外へのガス発生や漏液を防止
できる。Effects of the Invention As described above, in the sealed fulkaline battery equipped with the non-sintered nickel electrode of the present invention, charging and discharging characteristics can be maintained satisfactorily over a long period of time, and gas generation and liquid leakage to the outside of the battery can be prevented.

Claims (3)

【特許請求の範囲】[Claims] （１）電解液として比重が１．３２〜１．４０（２０℃
換算）の苛性カリ水溶液を用いた活物質合剤中に炭素粉
末を有する非焼結式ニッケル極を備えた密閉形アルカリ
蓄電池。(1) As an electrolyte, the specific gravity is 1.32 to 1.40 (20℃
A sealed alkaline storage battery equipped with a non-sintered nickel electrode containing carbon powder in the active material mixture using a caustic potassium aqueous solution (converted). （２）苛性カリ水溶液中に水酸化リチウムを１ｏ２／１
以上含むことを特徴とする特許請求の範囲第１項記載の
密閉形アルカリ蓄電池。(2) Lithium hydroxide in caustic potassium aqueous solution 1o2/1
A sealed alkaline storage battery according to claim 1, characterized in that it includes the above. （３）苛性カリ水溶液の比重が１．３４〜１．３８（２
０℃換算）の範囲であることを特徴とする特許請求の範
囲第１項記載の密閉形アルカリ蓄電池。(3) The specific gravity of the caustic potassium aqueous solution is 1.34 to 1.38 (2
2. The sealed alkaline storage battery according to claim 1, wherein the temperature is within the range of 0° C.