JPS58206060A - Nonaqueous electrolyte battery - Google Patents

Abstract

PURPOSE:To enlarge application as an appliance power source without detraction of performance from graphite fluoride family primary battery by mixing niobium pentaoxide to graphite fluoride. CONSTITUTION:A negative electrode using lithium as an active mass, an electrolyte prepared by dissolving an inorganic salt in organic solvent, and a positive electrode having an active mass prepared by mixing graphite fluoride and niobium pentaoxide are provided. Niobium pentaoxide having almost same potential as graphite fluoride was selected as an additional active mass from the reason that it gives no adverse effect to basic discharge performance of graphite fluoride family batteries, and reacts prior to or in parallel with graphite fluoride in initial discharge stage, and rechargeable LiaNb2O5 can exist as much as possible in the positive electrode to give rechargeability.

Description

【発明の詳細な説明】 本発明はリチウムを負極活物質とし、テトラハイドロフ
ラン、ディメトキシエタン、ディオキソラン、グロビレ
ンカーボネイト、γ−ブチロラクトンなどの非プロトン
性有機溶媒にホウフッ化リチウム、過塩素酸リチウムな
どの無機塩を溶解される単独物もしくは混在物および未
反応炭素を含有するものを含む）を正極の生活物質とす
る非水電解液電池の正極への補助活物質の添加に関する
ものである。Detailed Description of the Invention The present invention uses lithium as a negative electrode active material, and uses lithium borofluoride and lithium perchlorate in an aprotic organic solvent such as tetrahydrofuran, dimethoxyethane, dioxolane, globylene carbonate, and γ-butyrolactone. The present invention relates to the addition of an auxiliary active material to the positive electrode of a non-aqueous electrolyte battery in which the active material of the positive electrode is a substance containing an inorganic salt dissolved therein or a mixture thereof, and a material containing unreacted carbon.

上記のフッ化黒鉛を正極活物質として用いた非水電解液
電池は高エネルギー密度で電圧の平坦性が良く、貯蔵性
のすぐれた一次電池としてすでに広く実用化され、ます
ます用途の拡大が進んでいる。これらの新しい用途のう
ち、ＩＣメモリのバックアップ用電源で代表されるよう
にナノアンペアからマイクロアンペアオーダーの極めて
微少な電流ではあるが、バックアップ用電源としての一
次電池に長期間にわたり充電方向にリーク電流が流れ、
この程度の充電に対しては一次電池とは云いながらも電
池特性や外形、外観の異常、破裂等の問題がなく、−次
電池としての機能を正常に発揮し得ることが要求される
場合が多い。上記の如き微少電流も電子レジスタ、コン
ピュータなど応用機器の高信頼性、耐用年数の延長が進
み、バックアップ用電池に要求される耐用年数も１０年
はする場合もある。Non-aqueous electrolyte batteries using the above-mentioned fluorinated graphite as the positive electrode active material have high energy density and good voltage flatness, and have already been widely put into practical use as primary batteries with excellent storability, and their applications continue to expand. I'm here. Among these new applications, although it is an extremely small current on the order of nanoamperes to microamperes, as typified by backup power supplies for IC memory, leakage current in the charging direction for a long period of time is generated in primary batteries as backup power supplies. flows,
For this level of charging, even though it is a primary battery, it is required to be able to function normally as a secondary battery without any problems such as battery characteristics, external shape, abnormality in appearance, bursting, etc. many. Even with the above-mentioned minute current, the reliability and service life of electronic registers, computers, and other applied equipment have been extended, and the service life required for backup batteries may be as long as 10 years.

前記のフッ化黒鉛系の非水電解液電池は本質的に正極の
充電が不可能とされており、下記の如く放電反応は進む
が、その逆の電気化学的反応は進行しない１・これは、
（ＯＦ）Ｂ＋ｎＬｉ　＋　ｎ＠　−＋　ｃ＋　ＬｔＦに
より不活性なＬｉＦを生ずるためとされている〇したが
って、先述の充電電流が電池に流れると。In the above-mentioned fluorinated graphite-based non-aqueous electrolyte battery, it is essentially impossible to charge the positive electrode, and although the discharge reaction proceeds as shown below, the reverse electrochemical reaction does not proceed1. ,
(OF)B+nLi + n@ −+ c+ It is said that this is because LtF produces inactive LiF. Therefore, when the above-mentioned charging current flows to the battery.

溶媒の分解、重合反応を主体とした電気化学的反応によ
り、ガス発生や電解液の変質が起こり、著るしい場合は
電池の膨張や破裂および電池性能の劣化をひき起こす懸
念がある。Electrochemical reactions, mainly consisting of solvent decomposition and polymerization reactions, cause gas generation and deterioration of the electrolyte, and in severe cases, there is a concern that this may cause expansion or rupture of the battery and deterioration of battery performance.

その意味で、より長期間の耐用特性を備えさせるため、
放電容量の少なくとも一部に相当する充電電気量に耐え
るべく改良が必要とされる。In that sense, in order to provide longer-term durability,
Improvements are required to withstand the amount of charging electricity that corresponds to at least a portion of the discharge capacity.

本発明は、フッ化黒鉛系非水電解液電池の一次電池とし
ての本来のすぐれた性能を保持し、なおかつ、少くとも
部分的な充放電ができる特性を付加し、゛機器電源とし
ての応用範囲の拡大と適合性の増大を図ったものである
。The present invention maintains the original excellent performance of a fluorinated graphite-based non-aqueous electrolyte battery as a primary battery, and has the added characteristic of being able to be at least partially charged and discharged. The aim is to expand and increase compatibility.

本発明は上記電池の正極に、充放電可能な活物質である
五酸化ニオブ（Ｎｂ２Ｏ５）を混合したことを特徴とす
るものである。The present invention is characterized in that niobium pentoxide (Nb2O5), which is a chargeable and dischargeable active material, is mixed into the positive electrode of the battery.

Ｎｂ２Ｏ５は非水電解液中で正極として充放電が可能な
活物質として研究されており、電圧の平坦性や放電容量
はフッ化黒鉛など一次電池用活物質より劣るので一次電
池用としての魅力は乏しいが、二次電池用活物質として
の期待が持てる物質である０Ｎｂ２０５　　の充放電反
応はリチウム負極を対極とした場合１次式で表され、Ｌ
ｉ　のＮｂ２Ｏ５の取り込み、取り出しが行われる。い
わゆる可逆性のトポケミカル反応であり、前述のフッ化
黒鉛の放電反応と基本的な機構、を異にする。Nb2O5 is being researched as an active material that can be charged and discharged as a positive electrode in a non-aqueous electrolyte, but its voltage flatness and discharge capacity are inferior to active materials for primary batteries such as graphite fluoride, so it is not attractive as a material for primary batteries. The charging and discharging reaction of 0Nb205, which is a poor but promising material as an active material for secondary batteries, is expressed by a linear equation when a lithium negative electrode is used as the counter electrode, and L
i Nb2O5 is taken in and taken out. This is a so-called reversible topochemical reaction, and its basic mechanism is different from the above-mentioned discharge reaction of fluorinated graphite.

Ｎｂ２Ｏ５＋　ａＬｘ　＋　ａｓ　＃　ＬｉａＮｂ２０
５本発明は係る五酸化ニオブは充放電反応が可能で、正
極電位としてもフッ化黒鉛に近似していることに注目し
、これを−次電池用として極めてすぐれた活物質である
フッ化黒鉛に差金することにより、フッ化黒鉛系−次電
池としての特性を損うことなく、前述の如き実用時の充
電に対する耐性を付加したものである。Nb2O5+ aLx + as # LiaNb20
5 The present invention focuses on the fact that niobium pentoxide is capable of charge-discharge reactions and has a positive electrode potential close to that of fluorinated graphite, and uses it as fluorinated graphite, which is an extremely excellent active material for secondary batteries. By adding a charge to the battery, it is possible to add resistance to charging during practical use as described above without impairing the characteristics of a fluorinated graphite-based secondary battery.

また、本発明の効果を更に高めるにはフッ化黒鉛を生活
物質とした正極中に充電可能なＬｉＢＨｂ２０５を存在
させるのが好ましい。このＬｉＪｂ２０５は・例えば正
極中にＮｂ２Ｏ５を含む電池を構成後、放電容量の一部
を放電させることで達成でき、反応生成物であるＬｘａ
Ｎｂ２０５を正極内に存在させた後実用に供することが
可能であり、これによりたとえ使用初期、から充電方向
に電流が通ずることがあっても可逆反応によりＮｂ２Ｏ
５が生成し、電解液の分解、重合などに起因する前述の
問題は解決できる。Further, in order to further enhance the effects of the present invention, it is preferable that rechargeable LiBHb205 be present in the positive electrode using fluorinated graphite as a living substance. This LiJb205 can be achieved by, for example, discharging a part of the discharge capacity after configuring a battery containing Nb2O5 in the positive electrode, and the reaction product Lxa
It is possible to put Nb205 into practical use after it exists in the positive electrode, and even if current flows in the charging direction at the beginning of use, Nb2O can be produced by a reversible reaction.
5 is generated, and the above-mentioned problems caused by decomposition, polymerization, etc. of the electrolytic solution can be solved.

添加する補助活物質として、フッ化黒鉛と近似した電位
を有する五酸化ニオブを選択した重要な意義は、まずフ
ッ化黒鉛系電池の基本的な放電性能に悪影響を与えない
ことと、放電初期にフッ化黒鉛より優先して、あるいは
並行して反応し、充電が可能なＬｉａＮｂ２０ｓ　を使
用時に極力多く正極に存の化学的安定性も本発明の構成
を可能にした要件の一つである。ちなみにフッ化黒鉛は
炭素粉とフッ素の高温下での直接反応で得られる粉体で
、五酸化ニオブはニオブ酸化物中で最も安定で、通常、
ニオブ酸の強熱、あるいはニオブ塩溶液を硫酸処理して
得た白色物の強故、あるいはニオブの強熱により得られ
る。The important significance of selecting niobium pentoxide, which has a potential similar to that of fluorinated graphite, as the auxiliary active material to be added is that it does not have a negative effect on the basic discharge performance of fluorinated graphite batteries, and that it One of the requirements that made the configuration of the present invention possible is the chemical stability that exists in the positive electrode as much as possible when using LiaNb20s, which reacts preferentially or in parallel to fluorinated graphite and can be charged. By the way, graphite fluoride is a powder obtained by the direct reaction of carbon powder and fluorine at high temperatures, and niobium pentoxide is the most stable of the niobium oxides and is usually
It can be obtained by igniting niobic acid, by igniting a white substance obtained by treating a niobium salt solution with sulfuric acid, or by igniting niobium.

第１図は本発明の効果を確認するために試作した電池の
断面図である。第１図において、１はステンレススチー
ル製の封口板、２は１に溶接された同質のネットからな
る負極集電ネット、３は２に圧着されたリチウム負極、
４はポリプロピレン不織布のセパレータ、５はフッ化黒
鉛（（ＣＦ）ｎ）を主成分とし、炭素粉とフッ素樹脂お
よび五酸化ニオブ（Ｎｂ２Ｏ５）を後述の如く種々の配
合で混合して成型した正極、６はテタ／製の正極集電ネ
ットで、正極６に圧入されている。７はステンレススチ
ール製の電池ケース、８はポリプロピレン製のガスケッ
トで、封口は電池ケース７の開口部の内方への折りまげ
により果している。電池内にはプロピレンカーボネイト
とディメトキシエタンを容量比で１＝１に混合した溶媒
にホウフッ化リチウムを溶解させた電解液を注入してい
るＯ上記の構成にしたがって直径２０Ｍ、厚さ１．６編
の電池を第１表の如き種々の配合組成の正極を用いて試
作し試験を行ったＯなお、正極はフッ化黒鉛と五酸化ニ
オブとの重量の和を１００とし、これにアセチレンブラ
ックを１０、フッ素樹脂粉末を６の割合で一律に添加し
て混合、成型した。FIG. 1 is a cross-sectional view of a battery experimentally manufactured to confirm the effects of the present invention. In FIG. 1, 1 is a stainless steel sealing plate, 2 is a negative electrode current collector net made of a homogeneous net welded to 1, 3 is a lithium negative electrode crimped to 2,
4 is a polypropylene nonwoven fabric separator, 5 is a positive electrode mainly composed of fluorinated graphite ((CF)n), which is formed by mixing carbon powder, fluororesin, and niobium pentoxide (Nb2O5) in various formulations as described below; Reference numeral 6 denotes a positive electrode current collection net made by Teta, which is press-fitted into the positive electrode 6. 7 is a battery case made of stainless steel, 8 is a gasket made of polypropylene, and the sealing is accomplished by bending the opening of the battery case 7 inward. An electrolytic solution in which lithium fluoroborate is dissolved in a solvent mixed with propylene carbonate and dimethoxyethane at a volume ratio of 1=1 is injected into the battery. According to the above configuration, the battery has a diameter of 20 M and a thickness of 1.6 mm. Tests were conducted by making prototype batteries using positive electrodes with various compositions as shown in Table 1.The positive electrode was made using graphite fluoride and niobium pentoxide, with the sum of their weights being 100, and acetylene black added to this. 10. Fluororesin powder was uniformly added at a ratio of 6 parts, mixed, and molded.

第１表にはこのうち、活物質の配合比のみ示した。Table 1 shows only the blending ratio of the active materials.

（以下余白） 第１表 次にこれらの試作電池の放電特性および耐充電性につい
て評価した結果を示す。(The following is a blank space.) Table 1 Next, the results of evaluating the discharge characteristics and charge resistance of these prototype batteries are shown.

試験方法は部分放電後、その一部分の容量に相当する充
電を行うことをくり返し、機器において主にメモリバッ
クアップのまため放電し、ムＣ電源での駆動の際のリー
ク電流による充電がある期間性われるという実用状態に
応じた模似実験条件を設定して行った。充放電の条件と
順序は下記の通りである。The test method is to repeatedly charge a portion of the capacity after a partial discharge, and then discharge the device mainly to back up the memory. The simulation experiment conditions were set according to the practical situation in which the experiment will be carried out. The conditions and order of charging and discharging are as follows.

第１次放電：温度２０℃、ａｏＫΩ定抵抗負荷で↓　　
　　３６時間放電 （全体容量の約６％・・・・・・約ｓ、ｓｍＡｈ）第１
次充電：温度２０℃、１０μム定電流で２００１　　　
　時間充電 （２ｍＡｈ） 第２次放電：温度２０℃、３０にΩ定抵抗負荷で第２次
充電：°温度２０℃、１０μム定電流で７００時間充電 ↓　　（７ｍＡｈ） 第３次放電：温度２０’Ｃ，３０にΩ定抵抗負荷で、↓
　　　　端子電圧２．Ｏｖに降下するまで放電第３次充
電：温度２０”Ｃ，１０μム定電流でｓｏ。Primary discharge: Temperature 20℃, aoKΩ constant resistance load ↓
36 hour discharge (about 6% of total capacity...about s, smAh) 1st
Next charge: 2001 at temperature 20℃, 10μm constant current
Time charging (2mAh) Secondary discharge: Temperature 20℃, 30Ω constant resistance load Secondary charging: Temperature 20℃, 700 hours charging with 10μm constant current ↓ (7mAh) Tertiary discharge: Temperature 20 'C, 30Ω constant resistance load, ↓
Terminal voltage 2. Discharge until it drops to Ov.Third charge: Temperature 20"C, 10μm constant current so.

１　　　　時間充電 （ｓｍＡｈ） 最終放電：温度２０’ｃ、、ａｏｘΩ定抵抗負荷で、端
子電圧が２．ＯＶに降下するまで放電その試験結果のう
ち、第２図は放電特性を示し、第２表は充電後の電池の
膨張度合を充電後の電池厚さ寸法から未放電電池の厚さ
寸法を差し引いた値として示し、さらに最終放電におけ
る放電持続時間を示している０ （以下余白） 第２図および第２表よりＮｂ２Ｏ５の添加量が多い程、
充電後の膨張塵が少なく、充電が円滑に進んでいる。こ
れは最終放電時の持続時間の差からも裏付けられる。し
かし重量比で４６％以上のＮｂ２Ｏ５を含む場合は放電
後半の電圧低下が大きく、これは残存するＮｂ２Ｏ５に
よる放電の特性が支配的に表われているためと考えられ
、一方５％の添加では充電を十分に受けつける量のＮｂ
２Ｏ５としては若干不足気味で第３次放電の際、電池膨
張による接触不良のため電圧低下が若干見られる。これ
らの試験は模擬テストにすぎず、電池に要ボされる耐充
電性によって適切な配合をその都度選択すべきではある
が、常識的な見方で判断すれば、Ｎｂ２Ｏ５は全活物質
の１０〜３０重量％の添加量とするのが適切であろうと
思われる。一方、無添加の場合、第１回目の充電後の放
電では通常の間欠放電の場合と同様に異常なく放電が行
われるが、第２回目の充電の後の放電では電圧の低下と
不安定性を示している。これは充電によりガス発生が生
じ、第１回の充電では発生ガスが少量のため電池機能に
支障はなかったが、第２回目の充電に到りガス圧が増大
し、電池膨張や極間へのガスの介在などにより電池内の
接触不足が生じて内部抵抗が増大し、電圧特性が劣化し
たものと考えられる。1 hour charge (smAh) Final discharge: Temperature 20'C, aoxΩ constant resistance load, terminal voltage 2. Discharge until it drops to OV Among the test results, Figure 2 shows the discharge characteristics, and Table 2 shows the degree of expansion of the battery after charging by subtracting the thickness of the undischarged battery from the thickness of the battery after charging. 0 (blank below) shows the discharge duration in the final discharge. From Figure 2 and Table 2, the larger the amount of Nb2O5 added, the more
There is little expanding dust after charging, and charging progresses smoothly. This is also supported by the difference in duration of final discharge. However, when 46% or more of Nb2O5 by weight is contained, the voltage drop in the latter half of the discharge is large, and this is thought to be because the discharge characteristics due to the remaining Nb2O5 are dominant. Nb in an amount sufficient to accept
As 2O5, it is slightly insufficient, and during the tertiary discharge, there is a slight voltage drop due to poor contact due to battery expansion. These tests are only simulation tests, and the appropriate formulation should be selected each time depending on the charge resistance required for the battery, but if judged from a common sense perspective, Nb2O5 accounts for 10 to 10% of the total active materials. It seems appropriate to add 30% by weight. On the other hand, in the case of no additives, discharging after the first charge occurs without any abnormalities as in the case of normal intermittent discharge, but discharging after the second charge causes voltage drop and instability. It shows. This is because gas is generated during charging, and during the first charge, the amount of gas generated was small and did not affect the battery's function, but on the second charge, the gas pressure increased, causing the battery to expand and cause damage to the gap between the electrodes. It is thought that due to the presence of gas, insufficient contact occurred within the battery, increasing internal resistance and deteriorating the voltage characteristics.

また、以上の説明は正極の充放電特性についてのみ行な
ったが、負極の充放電の可逆性については本発明の場合
、−次電池の機能を補完するための部分的、かつサイク
ル回数の少い充電であるため、負極に析出するリチウム
の樹枝状結晶による内部短絡や脱落を懸念する心配はな
く、負極の実用性は通常のリチウムで十分で、さらに慎
重を期するならアルミニウムなどとの合金を用いてもよ
いＯ 以上の如く、本発明はフッ化黒鉛系電池の実用範囲の向
上と信頼性向上のために極めて効果の大きいものである
。In addition, although the above explanation has been made only regarding the charging and discharging characteristics of the positive electrode, in the case of the present invention, the reversibility of charging and discharging of the negative electrode is partially explained in order to supplement the function of the negative electrode and with a small number of cycles. Since it is charging, there is no need to worry about internal short circuits or falling off due to lithium dendrites deposited on the negative electrode, and ordinary lithium is sufficient for practical use as the negative electrode.If you want to be more careful, you can use alloys with aluminum etc. O may be used As described above, the present invention is extremely effective in improving the practical range and reliability of fluorinated graphite batteries.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図は本発明の実施例における電池の断面図。 第２図は本発明の効果を検討した電池の放電特性を示す
。 １・・・・・・封口板、２・・・・・・負極集電ネット
、３・・・・・・リチウム負極、４・・・・・セパレー
タ、５・・・正極。 ６・・・・・・正極集電ネット、７・・・・電池ケース
、８・・・・・・ガスケット。FIG. 1 is a sectional view of a battery in an embodiment of the present invention. FIG. 2 shows the discharge characteristics of a battery in which the effects of the present invention were investigated. DESCRIPTION OF SYMBOLS 1... Sealing plate, 2... Negative electrode current collection net, 3... Lithium negative electrode, 4... Separator, 5... Positive electrode. 6... Positive electrode current collection net, 7... Battery case, 8... Gasket.

Claims (1)

【特許請求の範囲】 （１）リチウムを活物質とした負極と、有機溶媒に無機
塩を溶解した電解液と、フッ化黒鉛と五酸化ニオブとを
混合して活物質とした正極を備えた非水電解液電池。 に））フッ化黒鉛と五酸化ニオブとの混合比が重量比で
９０：１０から７０：３０までである特許請求の範囲第
１項記載の非水電解液電池。 （３）リチウムを活物質とした負極と、有機溶媒に無機
塩を溶解した電解液と、フッ化黒鉛を生活物質とした正
極を備え、前記正極中には充電可能なＬｉａＮｂ２０６
を存在させた非水電解液電池。[Scope of Claims] (1) A negative electrode containing lithium as an active material, an electrolytic solution containing an inorganic salt dissolved in an organic solvent, and a positive electrode containing a mixture of graphite fluoride and niobium pentoxide as an active material. Nonaqueous electrolyte battery. 2)) The non-aqueous electrolyte battery according to claim 1, wherein the mixing ratio of graphite fluoride and niobium pentoxide is from 90:10 to 70:30 by weight. (3) Equipped with a negative electrode that uses lithium as an active material, an electrolyte that has an inorganic salt dissolved in an organic solvent, and a positive electrode that uses fluorinated graphite as a living material, and the positive electrode contains rechargeable LiaNb206.
A non-aqueous electrolyte battery with