JPS58206061A - Nonaqueous electrolyte battery - Google Patents

Abstract

PURPOSE:To increase the field of practical use and reliability in graphite fluoride famIly batteries by mixing titanium dioxide which is rechargeable active mass to a positive electrode. 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 titanium dioxide are provided. TiO2 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 TiO2.Li 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、テトラノ１イドロ
フラン、ディメトキシエタン、ディオキソラン、プロピ
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せた非水電解液を用い、フッ化黒
鉛（（ＣＦｘ）、ｎＱ　（ｚ　４１　、換言すれば（Ｏ
Ｆ　）　ｎ　＋　（０２Ｆ）ｎで表される単独物もしく
は混在物及び未反応炭素を含有するものを含む）を正極
の主、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, lithium perchlorate, etc. in an aprotic organic solvent such as tetranohydrofuran, dimethoxyethane, dioxolane, propylene carbonate, and γ-butyrolactone. Fluorinated graphite ((CFx), nQ (z 41 , in other words, (O
F) Addition of auxiliary active material to the positive electrode of a non-aqueous electrolyte battery in which the main active material of the positive electrode is n + (02F)n, either alone or as a mixture, and including those containing unreacted carbon. It is about addition.

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矧性が良く、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メモリのバックアンプ用電源で代表されるよう
にナノアンペアカラ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、−７
ンピユ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
年はおろか２０年という長期間の場合が通例であるため
、その間の累積される充電電気量が数ｍＡｈから数１０
ｍＡｈに達する場合もある。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. It's progressing. Among these new applications, although the current is extremely small on the order of nanoampere and microampere, as typified by the power supply for back-up amplifiers of IC memory, it leaks in the direction of charging over a long period of time to the primary battery as a backup power supply. current 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. The minute current as mentioned above is also an electronic resistor, -7
As the reliability and service life of applied equipment such as computers has been extended, the service life required for backup batteries has also increased to 10%.
Since it is common for a long period of 20 years, let alone a year, the amount of electricity accumulated during that time ranges from several mAh to several tens of mAh.
In some cases, it reaches mAh.

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。これは、（
ＣＦ）ｚｌ　＋　ｎＬｘ　＋　ｎｏ→Ｃ＋ＬｉＦ［より
不活性なＬｉＦを生ずるためとされている。In the fluorinated graphite-based non-aqueous electrolyte battery, it is essentially impossible to charge the positive electrode, and although the discharge reaction proceeds as described below, the reverse electrochemical reaction does not proceed. this is,(
CF) zl + nLx + no→C+LiF [supposedly to produce more inactive LiF.

従って、先述の充電電流が電池に流れると、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ｉ”液の変質が起こり、著るしい場合は電池の
膨張や破裂、及び電池性能の劣化をひき起こす懸念があ
る。Therefore, when the above-mentioned charging current flows through the battery, gas generation and deterioration of the electrolytic liquid occur due to electrochemical reactions mainly consisting of solvent decomposition and polymerization reactions, and in severe cases, battery expansion and There is a concern that it may cause rupture and deterioration of battery performance.

その意味で、より長期間の耐用特性を備へさせるため、
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 also adds the characteristic of at least partial charging and discharging, expanding the range of application as a power source for equipment. This is intended to 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
二酸化チタン（Ｔｉ０２）を混合することを特徴とする
ものである。The present invention is characterized in that titanium dioxide (Ti02), which is a chargeable and dischargeable active material, is mixed into the positive electrode of the battery.

Ｔ　ｉｏｚにはルチル型とアナターゼ型とがあり非水電
解液電池の正極活物質としての充放電特性は後者がより
すぐれたものとしておもに後者の研究が進められている
。しかし放電特性自体はフッ化黒鉛など一次の非水電解
液電池の正極に較べると　゛エネルギー密度、電圧の平
多旦性などの点で劣っているため、−次電゛頽ｌ活物質
としては魅力に乏しいが、充放電が可能な材料としては
注目に値するものである。There are two types of Tioz, rutile type and anatase type, and research on the latter is mainly underway as it has better charge and discharge characteristics as a positive electrode active material for non-aqueous electrolyte batteries. However, the discharge characteristics themselves are inferior in terms of energy density, voltage stability, etc. compared to the positive electrode of primary non-aqueous electrolyte batteries such as fluorinated graphite. Although it is not very attractive, it is worthy of attention as a material that can be charged and discharged.

Ｔｉ０ｚの充放電反応はリチウム負極を対極とした場合
、次式で表され、Ｌｌ　　のＴｉ０ｚへの取り込み、取
り出しによる可逆性のトポケミカル反応であシ、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。When a lithium negative electrode is used as a counter electrode, the charge/discharge reaction of Ti0z is expressed by the following formula, and is a reversible topochemical reaction due to the incorporation and extraction of Ll into Ti0z, which is similar to the discharge reaction of fluorinated graphite described above. The mechanism is different.

ＴｉＯ＋Ｌｉ″−＋　ｅ　ｄ　ＴｉＯ２・Ｌｉ本発明は
Ｔ　ｉ０２が充放電可能で、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、これ全−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補助活物質
として混合することにより、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
する耐性全付加したものである。又、本発明の効果を更
に高めるにはフッ化黒鉛金主活物質とした正極中に充電
可能なＴｉＯ２・Ｌｉを存在させるのが好ましい。TiO+Li''-+ e d TiO2・LiThe present invention focuses on the fact that TiO2 is chargeable and dischargeable and has a positive electrode potential close to that of fluorinated graphite, and considers it to be an extremely excellent active material for all-power batteries. By mixing a certain fluorinated graphite as an auxiliary active material, the battery has all the resistance to charging during practical use as described above without impairing the characteristics of a fluorinated graphite-based secondary battery.Also, the present invention In order to further enhance this effect, it is preferable to include chargeable TiO2.Li in the positive electrode, which uses fluorinated graphite gold as the main active material.

こＱ、ＴｉＯ２・Ｌｉは、例えばＴｉＯ２を正極中に含
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Ｔ　ｉ　Ｏ２・Ｉ、ｉ　　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ＴｉＯ２が生成し、電
解液の分解９重合などに起因する前述の問題は解決でき
る。正極に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ＴｉＯ２を選択した重要な意義は、
まづフッ化黒鉛系電池の基本的な放電性能に悪影響を与
へないことと、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、充電が可能な放電生成物である
ＴｉＯ２・Ｌｉを使用時に極力多く正極に存在させ充電
に備へることを可能にしたことにある。さらに周知の如
きＴｉＯ２の非水電解液中で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。This Q, TiO2.Li, can be achieved, for example, by configuring a battery containing TiO2 in the positive electrode and then discharging a part of the discharge capacity. It is possible to put it into practical use after
As a result, even if a current is passed in the charging direction from the beginning of use, TiO2 is generated by a reversible reaction, and the above-mentioned problems caused by decomposition and polymerization of the electrolytic solution can be solved. The important significance of selecting TiO2, which has a potential similar to that of fluorinated graphite, as the auxiliary active material added to the positive electrode is that
First, it does not have a negative effect on the basic discharge performance of fluorinated graphite batteries, and TiO2, which is a discharge product that reacts preferentially or in parallel to fluorinated graphite at the initial stage of discharge and can be charged.・It is possible to have as much Li as possible in the positive electrode during use to prepare for charging. Furthermore, the well-known chemical stability of TiO2 in a non-aqueous electrolyte is also one of the requirements that made the configuration of the present invention possible.

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、１ｒｒｉステンレスス
チール製の封目板、２は１に溶接された同質のネットか
ら成る負極集電ネット、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（（ｃｉ’）ｎ　）を主成分とし、炭素粉とフッ
素樹脂、及びＴｉＯ２を後述の如く種々の配合で混合し
て成型した正極、６はチタン製の正極集電ネットで、正
極６に圧入されている。了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［
１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。FIG. 1 is a cross-sectional view of a battery experimentally manufactured to confirm the effects of the present invention. In Figure 1, 1 is a sealing plate made of stainless steel, 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 separator made of polypropylene nonwoven fabric, and 5 is a separator made of polypropylene nonwoven fabric. The positive electrode is mainly composed of fluorinated graphite ((ci')n), and is formed by mixing carbon powder, fluororesin, and TiO2 in various formulations as described below. 6 is a positive electrode current collection net made of titanium; 6 is press-fitted. Number 8 is a stainless steel battery case, number 8 is a polypropylene gasket, and the seal [
1 is accomplished by folding 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.

上記の構成に従って直径２０間、厚さ１．６薗の電池を
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。なお正極はフッ化黒鉛と二酸化チタンとの重
量の和１１００とし、これにアセチレンブラックを１０
、フッ素樹脂粉末を５の割合で一律に添加して混合、成
型した。第１表にはこのうち活物質の配合のみ示した。Batteries having a diameter of 20mm and a thickness of 1.6mm were fabricated according to the above configuration using positive electrodes having various compositions as shown in Table 1, and tested. For the positive electrode, the sum of the weights of fluorinated graphite and titanium dioxide was 1100, and acetylene black was added to this by 100.
, fluororesin powder was uniformly added at a ratio of 5 parts, mixed, and molded. Table 1 shows only the active material formulations.

（以下余白） 第　　　１　　　表 次にこれらの試作電池の放電特性及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 charging 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
クアップのため放電し、ＡＣ電源での駆動の際のリーク
電流による充電がある期間行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 repeat a partial discharge and then charge it to a partial capacity.The device discharges mainly for memory backup, and then charges due to leakage current when running on an AC power source. The simulation experiment conditions were set according to practical conditions. The conditions and order of charging and discharging are as follows.

第１次放電：温度２０℃、３０にΩ定抵抗負荷で３６時
間放電（全体容量の約６ ↓　　　チ・・・・・・約３．５　ｍＡｈ　）第１次充
電：温度２０℃、１０μム定電流で↓　　　２００時間
充電（２ｍＡｈ） 第２次放電＝２０℃、３０にΩ定抵抗負荷で３５０時間
放電（全体容量の約５０ ↓　　　チ・・・・・・約ｓｓｍＡｈ）第２次充電：２
ｏ℃、１０μム定電流で７００↓　　　時間充電（７ｍ
Ａｈ　） 第３次放電＝２０℃、３０にΩ定抵抗負荷で端子電圧が
２．ＯＶに降下するまで放 ↓電 第３次充電：２０°Ｃｓ　１０　ｐム定電流で５００↓
　　　時間充電（ｓ　ｍｊｈ　） 最終放電　：２０℃、３０にΩ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、第３図は放電特性全示し
、第２図はアナターゼ型Ｔｉｅ２の添加址を変へ名湯台
の相違、第３図はＴｉＯ２の種類を変へた場合の相違を
示している。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。Primary discharge: Discharge for 36 hours at a temperature of 20°C with a constant resistance load of 30Ω (approx. 6 ↓ of total capacity...approximately 3.5mAh) Primary charge: Temperature of 20°C, 10μm Charge for 200 hours at constant current (2mAh) Secondary discharge = 20℃, discharge for 350 hours at 30Ω constant resistance load (approx. 2
Charging for 700↓ hours at 10μm constant current at o℃ (7m
Ah) Tertiary discharge = 20℃, 30Ω constant resistance load, terminal voltage 2. Discharge until it drops to OV ↓ Third charge: 20°Cs 10 pm constant current 500 ↓
Time charge (s mjh) Final discharge: 20°C, 30Ω constant resistance load, terminal voltage 2. Discharge until it drops to OV Of the test results, Figures 2 and 3 show the complete discharge characteristics, Figure 2 shows the difference in the addition of anatase type Tie2, and Figure 3 shows the difference in the addition of TiO2. It shows the difference when changing the type. Table 2 shows the degree of expansion of the battery after charging as a value obtained by subtracting the thickness of the undischarged battery from the thickness of the battery after charging, and also shows the discharge duration in the final discharge.

（以下余白） 第２図及び第２表よりアナターゼ型ＴｉＯ２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。しかし全活物質に対し重量比で４５チ以上のＴｉ
０２ｆ含む場合は放電後半の電圧低下が大きい。これは
残存するＴｌＯ２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ＴｉＯ２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の低下が
若干具られる。これらの試験は模擬テストにすぎず、電
池に要求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、Ｔ
　ｉ　Ｏ２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。(The following is a blank space) From FIG. 2 and Table 2, it is clear that the greater the amount of anatase-type TiO2 added, the less expanded dust is generated after charging, and the charging progresses smoothly. This is also supported by the difference in duration of final discharge. However, the weight ratio of Ti to the total active material is 45 or more.
When 02f is included, the voltage drop in the latter half of the discharge is large. This is thought to be because the discharge characteristics due to the remaining TlO2 are dominant, and on the other hand, the amount of TiO2 added at 5% is slightly insufficient to sufficiently accept charge, and during the tertiary discharge, the battery There is a slight drop in voltage due to poor contact due to expansion. These tests are only mock tests, and the appropriate formulation should be selected each time depending on the charge resistance required for the battery, but common sense suggests that T
It seems appropriate to add iO2 in an amount of 10 to 30% by weight of the total active material.

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回目の充電後の放電では電ＩＥの低下と不安定性を
示している。これは充電によリガス発生が生じ、第１回
目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て電池
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。On the other hand, in the case of no additives, the discharge after the first charge is performed without any abnormality as in the case of normal intermittent discharge, but
Discharge after the second charge shows a decrease in electrical IE and instability. This is because regas is generated during charging, and during the first charge, the amount of gas generated was small so there was no problem with the battery's function, but on the second charge, the gas pressure increased, causing the battery to expand and cause gaps between the electrodes. It is thought that the internal resistance increased due to lack of contact within the battery due to the presence of gas, etc., and the voltage characteristics deteriorated.

また、第３図及び第２表よりルチル型ＴｉＯ２において
も効果があるが、アナターゼ型ＴｉＯ２を混合した方が
より効果が大きいことを示している。Further, FIG. 3 and Table 2 show that although rutile type TiO2 is also effective, the effect is greater when anatase type TiO2 is mixed.

以−ヒの結果からフッ化黒鉛系電池の正極にＴｉＯ２を
混合することにより耐充電性は著しく向上し、とりわけ
重量比で全活物質の１０〜３０チのＴｉＯ２の混合が好
ましく、さらにＴｉＯ２のうちでもアナターゼ型ＴｉＯ
２の混合による効果が大きいことが確認された。From the results shown below, the charge resistance is significantly improved by mixing TiO2 into the positive electrode of a fluorinated graphite battery, and it is particularly preferable to mix 10 to 30 inches of TiO2 based on the total active material in terms of weight ratio. We also use anatase type TiO
It was confirmed that the effect of mixing 2 was large.

また、以−ヒ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だめの部分的、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
ムの樹脂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。In addition, although the following 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 can be partially and Because the charge is small, there is no need to worry about internal short circuits or falling off due to resinous lithium crystals deposited on the negative electrode, and ordinary lithium is sufficient for practical use as a negative electrode. An alloy may also be used.

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なものである
。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
、第３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・・・・・・ｉＥＩＩＭ、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 according to an example of the present invention, and FIGS. 2 and 3 show discharge characteristics of a battery in which the effects of the present invention were studied. DESCRIPTION OF SYMBOLS 1... Sealing plate, 2... Negative electrode current collection net, 3... Lithium negative electrode, 4... Separator, 5... iEIIM, 6...Positive electrode current collection net, 7...Battery case, 8...
·gasket.

Claims (1)

【特許請求の範囲】 ０）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、フッ化黒鉛と二酸化チタンとを混
合して活物質とした正極を備えた非水電解液電池。 （２）二酸化チタンがアナターゼ型である特許請求の範
囲第１項記載の非水電解液電池。 （３）　　フッ化黒鉛と二酸化チタンとの混合比が重量
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。 （４）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、フッ化黒鉛を主活物質とした正
極を備え、前記正極中には充電可能なＴｉＯ２・Ｌｉ　
ｆ存在させた非水電解液電池。[Scope of Claims] 0) A non-aqueous product comprising 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 fluorinated graphite and titanium dioxide as active materials. electrolyte battery. (2) The non-aqueous electrolyte battery according to claim 1, wherein the titanium dioxide is anatase type. (3) The non-aqueous electrolyte battery according to claim 1, wherein the mixing ratio of fluorinated graphite and titanium dioxide is from 90:10 to 70:30 by weight. (4) Equipped with a negative electrode using lithium as an active material, an electrolytic solution containing an inorganic salt dissolved in an organic solvent, and a positive electrode using fluorinated graphite as the main active material, and the positive electrode contains a rechargeable TiO2.Li
f non-aqueous electrolyte battery.