JP2001283912A - Polymer electrolyte secondary battery and its manufacturing method - Google Patents
Polymer electrolyte secondary battery and its manufacturing methodInfo
- Publication number
- JP2001283912A JP2001283912A JP2000093165A JP2000093165A JP2001283912A JP 2001283912 A JP2001283912 A JP 2001283912A JP 2000093165 A JP2000093165 A JP 2000093165A JP 2000093165 A JP2000093165 A JP 2000093165A JP 2001283912 A JP2001283912 A JP 2001283912A
- Authority
- JP
- Japan
- Prior art keywords
- polymer
- plasticizer
- negative electrode
- secondary battery
- 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.)
- Pending
Links
Classifications
-
- 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
-
- 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
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
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- Battery Electrode And Active Subsutance (AREA)
- Secondary Cells (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明はポリマー電解質二次
電池およびその製造方法に関し、さらに詳しくはサイク
ル寿命、極低温特性に優れたポリマー電解質二次電池お
よびその製造方法に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polymer electrolyte secondary battery and a method for producing the same, and more particularly, to a polymer electrolyte secondary battery having excellent cycle life and cryogenic characteristics and a method for producing the same.
【０００２】[0002]
【従来の技術】近年、電子機器の発達に伴い、小型で軽
量かつエネルギー密度が高く、更に繰り返し充放電が可
能な二次電池の開発が要望されている。このような二次
電池としては、リチウム金属又はリチウム合金を活物質
とする負極と、モリブデン、バナジウム、チタンあるい
はニオブなどの酸化物、硫化物もしくはセレン化物を活
物質とする正極とを具備したリチウム二次電池が知られ
ている。しかしながら、リチウム金属又はリチウム合金
を活物質とする負極を備えた二次電池は、充放電サイク
ルを繰り返すと負極にリチウムのデンドライトが析出す
るため、充放電サイクル寿命が短いという問題点があ
る。2. Description of the Related Art In recent years, with the development of electronic equipment, there has been a demand for the development of a secondary battery that is small, lightweight, has a high energy density, and can be repeatedly charged and discharged. As such a secondary battery, a lithium battery including a negative electrode using lithium metal or a lithium alloy as an active material, and a positive electrode using an oxide, sulfide, or selenide such as molybdenum, vanadium, titanium, or niobium as an active material is used. Secondary batteries are known. However, a secondary battery provided with a negative electrode using a lithium metal or a lithium alloy as an active material has a problem that the charge / discharge cycle life is short because lithium dendrites precipitate on the negative electrode when the charge / discharge cycle is repeated.
【０００３】このようなことから、負極に、例えばコー
クス、黒鉛、炭素繊維、樹脂焼成体、熱分解気相炭素の
ようなリチウムイオンを吸蔵放出する炭素質材料を用
い、ＬｉＰＦ6のような電解質をエチレンカーボネー
ト、プロピレンカーボネートのような有機溶媒に溶解さ
せた非水電解液を用いたリチウム二次電池が提案されて
いる。前記リチウム二次電池は、デンドライト析出によ
る負極特性の劣化を改善することができるため、充放電
サイクル寿命と安全性を向上することができる。[0003] For this reason, the negative electrode, for example coke, graphite, carbon fiber, resin fired body, a lithium ion, such as pyrolytic vapor carbon using a carbonaceous material for absorbing and releasing, electrolytes such as LiPF 6 A lithium secondary battery using a non-aqueous electrolyte in which is dissolved in an organic solvent such as ethylene carbonate or propylene carbonate has been proposed. Since the lithium secondary battery can improve the deterioration of the negative electrode characteristics due to the precipitation of dendrite, the charge and discharge cycle life and the safety can be improved.
【０００４】一方、電解質を固定化すると漏液の心配の
無い電池が得られることから、究極の電池と目されてき
たが、イオン伝導度が溶液系のものに比べて数桁低いな
どの問題があったため、汎用性のある電池の出現までに
は至らなかった。ところが、近年になってポリマーを有
機溶媒系の電解液と共にゲル化させると、イオン伝導度
が１０-3Ｓ／Ｃｍ程度に向上し、イオン伝導度の高いポ
リマー電解質が得られるようになり、これを電池のセパ
レータとして使用することにより特性の良い電池が得ら
れるようになったことから、ポリマー電池が脚光を浴び
るようになった。[0004] On the other hand, a battery with no fear of liquid leakage can be obtained by immobilizing the electrolyte, and it has been regarded as the ultimate battery. However, it has a problem that the ionic conductivity is several orders of magnitude lower than that of a solution type. However, it did not lead to the emergence of a versatile battery. However, in recent years, when a polymer is gelled with an organic solvent-based electrolyte, the ionic conductivity is improved to about 10 −3 S / Cm, and a polymer electrolyte having a high ionic conductivity can be obtained. The use of as a battery separator has made it possible to obtain batteries with good characteristics, and polymer batteries have come into the spotlight.
【０００５】米国特許第５２９６３１８号公報には正
極、負極の結着剤およびセパレータにポリマーを用いる
ことにより柔軟性が付与されたハイブリットポリマー電
解質を有する再充電可能なリチウムインターカレーショ
ン電池、即ちポリマー電解質二次電池が開示されてい
る。US Pat. No. 5,296,318 discloses a rechargeable lithium intercalation battery having a hybrid polymer electrolyte which has been rendered flexible by using polymers for the positive and negative electrode binders and separators, ie, a polymer electrolyte. A secondary battery is disclosed.
【０００６】正極は例えば、リチウムコバルト複合酸化
物からなる活物質と、ビニリデンフロライド−ヘキサフ
ルオロピレンの共重合体Ｐ（ＶＤＦ−ＨＦＰ）からなる
ポリマーと、ＤＢＰ（フタル酸ジブチル）などの可塑剤
とを含む正極用ペーストをアルミニウム製の集電体に塗
布、乾燥、圧延した後、所定の寸法に切断して正極が作
製される。The positive electrode is made of, for example, an active material composed of a lithium-cobalt composite oxide, a polymer composed of a copolymer P (VDF-HFP) of vinylidene fluoride-hexafluoropyrene, and a plasticizer such as DBP (dibutyl phthalate). Is coated on an aluminum current collector, dried and rolled, and then cut into predetermined dimensions to produce a positive electrode.
【０００７】そして、負極は例えば、リチウムイオンを
吸蔵放出が可能な黒鉛のような炭素質材料からなる活物
質と、ビニリデンフロライド−ヘキサフルオロピレンの
共重合体Ｐ（ＶＤＦ−ＨＦＰ）からなるポリマーと、Ｄ
ＢＰ（フタル酸ジブチル）などの可塑剤とを含む負極用
ペーストを銅製の集電体に塗布、乾燥、圧延した後、所
定の寸法に切断して負極が作製される。The negative electrode is made of, for example, an active material composed of a carbonaceous material such as graphite capable of inserting and extracting lithium ions, and a polymer composed of a copolymer P (VDF-HFP) of vinylidene fluoride-hexafluoropyrene. And D
A negative electrode paste containing a plasticizer such as BP (dibutyl phthalate) is applied to a copper current collector, dried and rolled, and then cut into predetermined dimensions to produce a negative electrode.
【０００８】次に、前記正極板及び負極板の間に電解液
を未含浸のＰ（ＶＤＦ−ＨＦＰ）からなるポリマー製セ
パレータを介在させ、１３０℃に加熱した剛性ロールに
て加熱圧着して積層化する。次に前記積層膜中に含まれ
る可塑剤をキシレンなどの有機溶媒を用いて抽出し、温
度が１００℃の真空減圧下で乾燥する。このようにして
得られた発電要素を、樹脂フィルムの間にアルミニウム
箔を配して全体を積層一体化したラミネートシートから
なる袋状外装（以下これを外装ケースという）の内部に
収容し、非水電解液を注入し、加温処理を施して正極
板、負極板中のポリマー及びセパレータをゲル化させ
て、非水電解液を吸収保持させていた。Next, a polymer separator made of P (VDF-HFP) not impregnated with an electrolytic solution is interposed between the positive electrode plate and the negative electrode plate, and laminated by heating and pressing with a rigid roll heated to 130 ° C. . Next, the plasticizer contained in the laminated film is extracted using an organic solvent such as xylene, and dried at a temperature of 100 ° C. under reduced pressure. The power generation element thus obtained is housed inside a bag-shaped exterior (hereinafter referred to as an exterior case) made of a laminated sheet in which an aluminum foil is disposed between resin films and the whole is laminated and integrated. An aqueous electrolyte was injected, and a heating treatment was performed to gel the polymer and the separator in the positive electrode plate and the negative electrode plate, thereby absorbing and holding the non-aqueous electrolyte.
【０００９】[0009]
【発明が解決しようとする課題】しかしながら、前記の
如く製造されたゲル電解質中の非水系電解液の量や均一
性は、電極合剤製造時に混入された可塑剤によって三次
元的に形成される細孔に依存する。この細孔部は非水系
電解液によって膨潤しゲル電解質を選択的に形成するた
めである。However, the amount and uniformity of the non-aqueous electrolyte in the gel electrolyte produced as described above are three-dimensionally formed by the plasticizer mixed during the production of the electrode mixture. Depends on the pore. The pores are swelled by the non-aqueous electrolyte to selectively form a gel electrolyte.
【００１０】従って、前記ゲル電解質中の非水系電解液
の量や均一性を制御することはサイクル特性や極低温環
境下での充放電特性などの電池特性に優れたポリマー電
解質二次電池を製造するのに必須であると考えられる。Therefore, controlling the amount and uniformity of the non-aqueous electrolyte in the gel electrolyte makes it possible to manufacture a polymer electrolyte secondary battery having excellent battery characteristics such as cycle characteristics and charge / discharge characteristics in an extremely low temperature environment. It is considered essential for
【００１１】従来技術では、電極合剤製造時の可塑剤量
の上限は制限を受けてきた。即ち、可塑剤量を増大させ
ていった場合、正極もしくは負極電極製造時の圧延性が
著しく低下して、所望とする電極厚みを得ることが困難
となるためである。また、前述の如く可塑剤量が限定さ
れるため、正極や負極の電極内部の三次元的に形成され
る細孔分布の均一性を得ることが困難となる。In the prior art, the upper limit of the amount of the plasticizer at the time of manufacturing the electrode mixture has been limited. That is, when the amount of the plasticizer is increased, the rollability at the time of manufacturing the positive electrode or the negative electrode is significantly reduced, and it is difficult to obtain a desired electrode thickness. In addition, since the amount of the plasticizer is limited as described above, it is difficult to obtain uniformity of a three-dimensionally formed pore distribution inside the positive electrode and the negative electrode.
【００１２】本発明は有機溶媒に可溶性でかつポリマー
と非溶解性の第１の可塑剤と、ポリマー膨潤性のある第
２の可塑剤を併用することにより、電解液を吸収保持す
る第１の細孔部に加えて、ゲルマトリックスの構築に利
用される第２の細孔部を増加させることにより、ゲル電
解質に含有される非水系電解液の量及びその均一性を向
上させ、サイクル寿命や極低温特性に優れた電池、及び
その製造方法を提供することを目的とする。According to the present invention, a first plasticizer which is soluble in an organic solvent and is insoluble in a polymer and a second plasticizer which has a polymer swelling property are used in combination to form a first plasticizer which absorbs and retains an electrolytic solution. In addition to the pores, by increasing the number of second pores used for the construction of the gel matrix, the amount of nonaqueous electrolyte contained in the gel electrolyte and its uniformity are improved, and the cycle life and An object of the present invention is to provide a battery having excellent cryogenic characteristics and a method for manufacturing the battery.
【００１３】[0013]
【課題を解決するための手段】上記の目的を達成するた
めの本発明は、リチウム含有複合酸化物を活物質とする
正極とリチウムイオンを吸蔵、放出が可能な炭素質材料
を活物質とする負極及び非水系電解液を吸収保持するポ
リマーゲル電解質からなるポリマー電解質二次電池にお
いて、前記正極および／または負極の電極合材中に非水
系電解液を吸収保持するためのポリマーが、大きさの異
なる少なくとも２種類以上の細孔を具備するポリマー電
解質二次電池およびその製造方法を提供するものであ
る。In order to achieve the above object, the present invention provides a positive electrode using a lithium-containing composite oxide as an active material and a carbonaceous material capable of occluding and releasing lithium ions as an active material. In a polymer electrolyte secondary battery comprising a negative electrode and a polymer gel electrolyte that absorbs and retains a non-aqueous electrolyte, a polymer for absorbing and retaining a non-aqueous electrolyte in the electrode mixture of the positive electrode and / or the negative electrode has a size. An object of the present invention is to provide a polymer electrolyte secondary battery having at least two or more different pores and a method for producing the same.
【００１４】有機溶媒に可溶性でかつポリマーと非溶解
性のあるフタル酸ジブチル（ＤＢＰ）のような第１の可
塑剤により、大きさが１００ｎｍから１０μｍで三次元
的に形成される第１の細孔に加え、ポリマー膨潤性のあ
るエチルメチルカーボネート（ＥＭＣ）のようなカーボ
ネート類からなる低沸点の第２の可塑剤により、結晶化
を防止し、ゲルマトリックスを構築する大きさが１００
ｎｍ未満の第２の細孔を負極、正極の内部に同時に形成
することにより、含有される非水系電解液の量及びその
均一性を向上させることができ、サイクル寿命や極低温
特性に優れた電池、及びその製造方法を提供するもので
ある。A first plasticizer, such as dibutyl phthalate (DBP), which is soluble in an organic solvent and insoluble in a polymer, is formed into a first fine particle having a size of 100 nm to 10 μm and formed three-dimensionally. In addition to the pores, a low-boiling second plasticizer of carbonates, such as polymer swellable ethyl methyl carbonate (EMC), prevents crystallization and creates a gel matrix size of 100.
By simultaneously forming the second pores of less than nm inside the negative electrode and the positive electrode, the amount of the nonaqueous electrolyte contained and the uniformity thereof can be improved, and the cycle life and the cryogenic characteristics are excellent. A battery and a method for manufacturing the battery are provided.
【００１５】さらに、第２の可塑剤として沸点が１３０
℃以下の低沸点のカーボネート類を用いることで正極お
よび／または負極の厚みを所望とする厚さまで圧延する
ことができる。即ち、正極および／または負極の電極合
材用ペーストを集電体上に塗布した後、第２の可塑剤の
沸点よりも高い１３０℃程度の温度で乾燥させることに
より第２の可塑剤は揮発し、第２の細孔が電極合材内に
形成され、残留することがないためである。Further, the second plasticizer having a boiling point of 130
By using carbonates having a low boiling point of not more than ℃, the thickness of the positive electrode and / or the negative electrode can be rolled to a desired thickness. That is, the paste for the electrode mixture of the positive electrode and / or the negative electrode is applied on the current collector, and then dried at a temperature of about 130 ° C. higher than the boiling point of the second plasticizer, whereby the second plasticizer is volatilized. However, the second pores are formed in the electrode mixture and do not remain.
【００１６】[0016]
【発明の実施の形態】以下、本発明の実施の形態につい
て図面を用いて説明する。Embodiments of the present invention will be described below with reference to the drawings.
【００１７】図１および図２は本発明の製造方法による
ポリマー電解質二次電池の上面図および断面図である。
正極１は正極活物質と導電剤および結着剤兼電解液吸収
保持剤としてのポリマーを有機溶媒に混練分散させたペ
ーストをアルミニウム箔製集電体１ａの両面に塗着、乾
燥、圧延して、正極活物質層１ｂとしたものである。こ
の２枚の正極の間に、セパレータ３を配置させ、このセ
パレータ３間に炭素質材料と前記結着剤兼電解液吸収保
持剤としてのポリマーを有機溶媒に混練分散させたペー
ストを銅箔製集電体２ａの両面に塗着、乾燥、圧延し
て、負極活物質層２ｂを形成した負極２があり、全体が
図２に示すように一体化されて発電要素４が構成され
る。このときの正極および／または負極の混練には、有
機溶媒に可溶性で、かつポリマーと非溶解性の第１の可
塑剤とポリマー膨潤性があり、かつ低沸点である第２の
可塑剤を混合して用いる。1 and 2 are a top view and a sectional view of a polymer electrolyte secondary battery according to the manufacturing method of the present invention.
The positive electrode 1 is prepared by applying a paste obtained by kneading and dispersing a positive electrode active material and a polymer as a conductive agent, a binder and an electrolyte absorbing and retaining agent in an organic solvent to both surfaces of an aluminum foil current collector 1a, drying and rolling. And the positive electrode active material layer 1b. A separator 3 is disposed between the two positive electrodes, and a paste obtained by kneading and dispersing a carbonaceous material and a polymer as the binder and the electrolyte-absorbing and holding agent in an organic solvent between the separators 3 is made of copper foil. There is a negative electrode 2 in which a negative electrode active material layer 2b is formed by coating, drying, and rolling on both surfaces of a current collector 2a, and the entirety is integrated as shown in FIG. At this time, the positive electrode and / or the negative electrode are kneaded by mixing a first plasticizer which is soluble in an organic solvent and is insoluble in a polymer with a second plasticizer which has a polymer swelling property and a low boiling point. Used.
【００１８】また、セパレータとしては、非水電解液を
吸収保持するものであれば良く、ビニリデンフロライド
−ヘキサフルオロピレンの共重合体Ｐ（ＶＤＦ−ＨＦ
Ｐ）に代表されるポリマーやポリエチレン樹脂、ポリプ
ロピレン樹脂などのポリオレフィン樹脂からなる不織布
を用いることができる。The separator may be any as long as it absorbs and retains the non-aqueous electrolyte, and is a copolymer P (VDF-HF) of vinylidene fluoride-hexafluoropyrene.
A nonwoven fabric made of a polymer represented by P) or a polyolefin resin such as a polyethylene resin or a polypropylene resin can be used.
【００１９】１Ｃは正極の集電体に設けたリード取り付
け部であり、ここには正極リード５が溶接されている。
２Ｃは負極の集電体に設けたリード取り付け部であり、
ここには負極リード６が溶接されている。７は金属箔を
中間の一層とし、その内側に樹脂フィルムを、外側にも
樹脂フィルムを積層一体化したラミネートフィルムから
なる外装ケースである。この外装ケース７の内部に収容
された前記発電要素４は、正極のリード５および負極の
リード６が外装ケース７の外部へ引き出され、その先端
が出入力端子８、９とされている。１０、１１はリード
５、６の中間部分に設けられた絶縁保護フィルムであ
り、外装ケース７の開口部を熱融着などで封口する際に
リード５、６の電気的絶縁と気密を確保するものであ
る。尚、外装ケース７は、前記ラミネートフィルムを帯
状に切断し、その長さ方向の中央部Ｔで２つ折りし、上
下の２辺Ｐ１とＰ２を予め熱融着したものであり、開口
している残り１辺のＰ３部分から発電要素４を挿入し、
所定量の非水電解液を注入する。この時の非水電解液は
電解質にＬｉＰＦ6を用い、溶媒にはＥＣ（エチレンカ
ーボネート）とＥＭＣとＤＥＣ（ジエチルカーボネー
ト）の混合溶媒を用いた。Reference numeral 1C denotes a lead mounting portion provided on the current collector of the positive electrode, to which a positive electrode lead 5 is welded.
2C is a lead attachment portion provided on the negative electrode current collector,
The negative electrode lead 6 is welded here. Reference numeral 7 denotes an outer case made of a laminated film in which a metal foil is used as an intermediate layer, a resin film is laminated on the inner side, and a resin film is laminated and integrated on the outer side. The power generating element 4 housed inside the outer case 7 has a positive electrode lead 5 and a negative electrode lead 6 drawn out of the outer case 7, and the leading ends thereof are input / output terminals 8 and 9. Reference numerals 10 and 11 denote insulating protective films provided at intermediate portions of the leads 5 and 6, which secure electrical insulation and airtightness of the leads 5 and 6 when the opening of the outer case 7 is sealed by heat sealing or the like. Things. The outer case 7 is formed by cutting the laminate film into a strip shape, folding the laminate film at the center T in the length direction thereof, and heat-sealing the upper and lower sides P1 and P2 in advance, and has an opening. Insert the power generating element 4 from the P3 part on the remaining side,
Inject a predetermined amount of non-aqueous electrolyte. At this time, LiPF 6 was used for the electrolyte as the non-aqueous electrolyte, and a mixed solvent of EC (ethylene carbonate), EMC, and DEC (diethyl carbonate) was used as the solvent.
【００２０】次に、９０℃〜１００℃で加温処理を施し
て、正極板、負極板中のポリマー及びセパレータをゲル
化し、非水電解液を吸収保持させた後、外装ケースの一
部を開封して内部に溜まったガスを排出した後、外装ケ
ースを再度封口するポリマー電解質二次電池の製造方法
である。Next, a heating treatment is performed at 90 ° C. to 100 ° C. to gel the polymer and the separator in the positive electrode plate and the negative electrode plate, and to absorb and hold the nonaqueous electrolyte. This is a method for manufacturing a polymer electrolyte secondary battery in which after opening and discharging gas accumulated inside, the outer case is closed again.
【００２１】[0021]
【実施例】本発明を実施例と比較例によって更に詳細に
説明する。The present invention will be described in more detail with reference to examples and comparative examples.
【００２２】（実施例１）正極１はコバルト酸リチウム
を主成分とする正極活物質１００重量部と導電剤として
のアセチレンブラック５重量部および結着剤兼電解液吸
収保持剤としてのポリマーであるフッ化ビニリデン（Ｖ
ＤＦ）とヘキサフルオロプロピレン（ＨＦＰ）との共重
合体Ｐ（ＶＤＦ−ＨＦＰ）８重量部と第１の可塑剤のＤ
ＢＰ（フタル酸ジブチル）１２重量部をＮＭＰ（Ｎ−メ
チル−２−ピロリドン）からなる有機溶媒に混練分散さ
せたペーストをラス加工した厚さ４０μｍのアルミニウ
ム箔製集電体１ａの両面に塗着、乾燥、圧延した後、所
定の寸法に切断して、正極活物質層１ｂとしたものであ
る。Example 1 A positive electrode 1 is 100 parts by weight of a positive electrode active material containing lithium cobalt oxide as a main component, 5 parts by weight of acetylene black as a conductive agent, and a polymer as a binder and an electrolyte absorbing and retaining agent. Vinylidene fluoride (V
8 parts by weight of a copolymer P (VDF-HFP) of DF) and hexafluoropropylene (HFP) and D of the first plasticizer
A paste in which 12 parts by weight of BP (dibutyl phthalate) is kneaded and dispersed in an organic solvent composed of NMP (N-methyl-2-pyrrolidone) is applied to both surfaces of a lath-processed 40 μm-thick aluminum foil current collector 1a. After being dried and rolled, it is cut into a predetermined size to form a positive electrode active material layer 1b.
【００２３】負極２はカーボン粉末１００重量部と前記
結着剤兼電解液吸収保持剤としてのポリマーであるＰ
（ＶＤＦ−ＨＦＰ）の粉末１５重量部と第１の可塑剤の
ＤＢＰ（フタル酸ジブチル）２１重量部と第２の可塑剤
であるＥＭＣ（エチルメチルカーボネート）１０重量部
をアセトンとシクロヘキサノンからなる混合有機溶媒に
混練分散させたペーストをラス加工した銅箔製集電体２
ａの両面に塗着した後、１３０℃の温度で乾燥する。Ｅ
ＭＣ（エチルメチルカーボネート）からなる第２の可塑
剤は沸点がおよそ１０８℃であるためこの乾燥工程で揮
発し負極合材層中には残留しない。次に前記負極合材層
を所望の厚さまで圧延した後、所定の寸法に切断して負
極活物質層２ｂとしたものである。The negative electrode 2 is composed of 100 parts by weight of carbon powder and P, which is a polymer serving as the binder and electrolyte absorbing and retaining agent.
Mixing of 15 parts by weight of (VDF-HFP) powder, 21 parts by weight of DBP (dibutyl phthalate) as a first plasticizer, and 10 parts by weight of EMC (ethyl methyl carbonate) as a second plasticizer, comprising acetone and cyclohexanone Copper foil current collector 2 obtained by lathing a paste kneaded and dispersed in an organic solvent 2
After coating on both sides of a, it is dried at a temperature of 130 ° C. E
Since the second plasticizer composed of MC (ethyl methyl carbonate) has a boiling point of about 108 ° C., it volatilizes in this drying step and does not remain in the negative electrode mixture layer. Next, after rolling the negative electrode mixture layer to a desired thickness, the negative electrode mixture layer is cut into a predetermined size to form a negative electrode active material layer 2b.
【００２４】２枚の正極活物質層の間に、Ｐ（ＶＤＦ−
ＨＦＰ）のフィルムからなるセパレータ３を配置させ、
このセパレータ３間に負極を配置し１３０℃に加熱した
剛性ロールにて加熱圧着して一体化する。Between the two positive electrode active material layers, P (VDF-
HFP), a separator 3 made of a film,
The negative electrode is arranged between the separators 3 and is integrated by being press-bonded with a rigid roll heated to 130 ° C.
【００２５】次に前記発電要素中に含まれる可塑剤のＤ
ＢＰをキシレンなどの有機溶媒を用いて抽出し、温度１
００℃の真空減圧下で乾燥する。Next, D of the plasticizer contained in the power generating element
BP was extracted using an organic solvent such as xylene,
Dry under reduced pressure at 00 ° C.
【００２６】１Ｃは正極の集電体に設けたリード取り付
け部であり、ここにはアルミニウム製正極リード５が溶
接されている。２Ｃは負極の集電体に設けたリード取り
付け部であり、ここには銅箔製負極リード６が溶接され
ている。７はアルミニウム箔を中間の一層とし、その内
側にポリプロピレンフィルムを、外側にポリエチレンテ
レフタレートフィルムとナイロンフィルムを積層一体化
したアルミラミネートフィルムからなる外装ケースであ
る。この外装ケース７の内部に収容された発電要素４
は、正極のリード５および負極のリード６が外装ケース
７の外部へ引き出され、その先端が出入力端子８、９と
されている。Reference numeral 1C denotes a lead mounting portion provided on the positive electrode current collector, to which an aluminum positive electrode lead 5 is welded. Reference numeral 2C denotes a lead attachment portion provided on the current collector of the negative electrode, to which a copper foil negative electrode lead 6 is welded. Reference numeral 7 denotes an outer case made of an aluminum laminated film having an aluminum foil as an intermediate layer, a polypropylene film on the inner side, and a polyethylene terephthalate film and a nylon film laminated and integrated on the outer side. The power generating element 4 housed inside the outer case 7
The lead 5 of the positive electrode and the lead 6 of the negative electrode are drawn out of the exterior case 7, and the ends thereof are input / output terminals 8 and 9.
【００２７】１０、１１はリード５、６の中間部分に設
けられた絶縁保護フィルムであり、外装ケース７の開口
部を熱融着などで封口する際にリード５、６の電気的絶
縁と気密を確保するものである。Reference numerals 10 and 11 denote insulating protective films provided at intermediate portions of the leads 5 and 6, which are used to electrically insulate and airtighten the leads 5 and 6 when the opening of the outer case 7 is sealed by heat sealing or the like. Is to ensure.
【００２８】注液には電解質にＬｉＰＦ6を、溶媒には
ＥＣ（エチレンカーボネート）とＥＭＣとＤＥＣ（ジエ
チルカーボネート）の混合溶媒からなる非水電解液を用
い、ＥＣ／ＥＭＣ／ＤＥＣの体積含有率を３０％、５０
％、２０％とした。For the injection, LiPF 6 is used for the electrolyte, and for the solvent, a non-aqueous electrolyte consisting of a mixed solvent of EC (ethylene carbonate), EMC and DEC (diethyl carbonate) is used, and the volume content of EC / EMC / DEC is used. 30%, 50
% And 20%.
【００２９】次に、９０℃〜１００℃で加温処理を施し
て、正極板、負極板中のポリマー及びセパレータをゲル
化し、非水電解液を吸収保持させた後、外装ケースの一
部を開封して０．４ＭＰａの荷重で１秒間押さえて、内
部に溜まったガスを排出した後、外装ケースを再度封口
して、電池容量が５００ｍＡｈのポリマー電解質二次電
池を得た。Next, a heating treatment is performed at 90 ° C. to 100 ° C. to gel the polymer and the separator in the positive electrode plate and the negative electrode plate, to absorb and hold the non-aqueous electrolyte, and then to remove part of the outer case. The package was opened and pressed with a load of 0.4 MPa for 1 second to discharge gas accumulated inside, and then the outer case was closed again to obtain a polymer electrolyte secondary battery having a battery capacity of 500 mAh.
【００３０】（実施例２）正極の混練分散工程におい
て、第１の可塑剤としてＤＢＰを１２重量部、第２の可
塑剤としてＥＭＣを４重量部、負極の混練分散工程にお
いて、第１の可塑剤としてＤＢＰを２１重量部、第２の
可塑剤としてＥＭＣを１０重量部とした以外は実施例１
と同様にして、電池容量が５００ｍＡｈのポリマー電解
質二次電池を得た。(Example 2) In the kneading and dispersing step of the positive electrode, 12 parts by weight of DBP as the first plasticizer, 4 parts by weight of EMC as the second plasticizer, and the first plasticizing step in the kneading and dispersing step of the negative electrode. Example 1 except that 21 parts by weight of DBP was used as an agent and 10 parts by weight of EMC as a second plasticizer.
In the same manner as in the above, a polymer electrolyte secondary battery having a battery capacity of 500 mAh was obtained.
【００３１】（実施例３）正極の混練分散工程におい
て、第１の可塑剤としてＤＢＰを１０重量部、第２の可
塑剤としてＥＭＣを８重量部、負極の混練分散工程にお
いて、第１の可塑剤としてＤＢＰを２８重量部、第２の
可塑剤は添加しなかった以外は実施例１と同様にして、
電池容量が５００ｍＡｈのポリマー電解質二次電池を得
た。Example 3 In the kneading and dispersing step of the positive electrode, 10 parts by weight of DBP as the first plasticizer, 8 parts by weight of EMC as the second plasticizer, and the first plasticizer in the kneading and dispersing step of the negative electrode. As in Example 1, except that 28 parts by weight of DBP and no second plasticizer were added as an agent,
A polymer electrolyte secondary battery having a battery capacity of 500 mAh was obtained.
【００３２】（実施例４）正極の混練分散工程におい
て、第１の可塑剤としてＤＢＰを１２重量部、第２の可
塑剤としてＤＭＣを４重量部、負極の混練分散工程にお
いて、第１の可塑剤としてＤＢＰを２１重量部、第２の
可塑剤としてＥＭＣを１０重量部とした以外は実施例１
と同様にして、電池容量が５００ｍＡｈのポリマー電解
質二次電池を得た。Example 4 In the kneading and dispersing step of the positive electrode, 12 parts by weight of DBP was used as the first plasticizer, 4 parts by weight of DMC was used as the second plasticizer, and the first plasticizer was used in the kneading and dispersing step of the negative electrode. Example 1 except that 21 parts by weight of DBP was used as an agent and 10 parts by weight of EMC as a second plasticizer.
In the same manner as in the above, a polymer electrolyte secondary battery having a battery capacity of 500 mAh was obtained.
【００３３】（比較例１）負極の混練分散工程におい
て、第１の可塑剤としてＤＢＰを２１重量部、第２の可
塑剤は添加しなかった以外は実施例１と同様にして、電
池容量が５００ｍＡｈのポリマー電解質二次電池を得
た。Comparative Example 1 In the kneading and dispersing step of the negative electrode, the battery capacity was reduced in the same manner as in Example 1 except that 21 parts by weight of DBP was added as the first plasticizer and the second plasticizer was not added. A 500 mAh polymer electrolyte secondary battery was obtained.
【００３４】実施例１〜実施例４、比較例１で得られた
各電池のサイクル寿命は０．２ＣｍＡ（１００ｍＡ）の
充電電流で４．２Ｖになるまで充電した後、１．０Ｃｍ
Ａ（５００ｍＡ）の電流値で３．０Ｖまで放電を行い、
この１サイクル目の放電容量を１００％とし、４００サ
イクル後の容量維持率を求めた結果を表１に示す。ま
た、極低温特性は２０℃の環境下で０．２ＣｍＡ（１０
０ｍＡ）の充電電流で４．２Ｖになるまで充電した後、
２０℃の環境下で０．２ＣｍＡ（１００ｍＡ）の電流値
で３．０Ｖまで放電を行ったときの放電容量を１００％
とし、−２０℃の環境下で０．２ＣｍＡ（１００ｍＡ）
の電流値で３．０Ｖまで放電を行ったときの放電容量比
率を求めた結果を表１に示す。The cycle life of each of the batteries obtained in Examples 1 to 4 and Comparative Example 1 was charged at a charging current of 0.2 CmA (100 mA) to 4.2 V, and then 1.0 Cm.
A is discharged to 3.0 V at a current value of A (500 mA),
The discharge capacity in the first cycle is defined as 100%, and the capacity retention rate after 400 cycles is shown in Table 1. In addition, the cryogenic characteristic is 0.2 CmA (10
0 mA) after charging until it reaches 4.2 V,
100% discharge capacity when discharging to 3.0 V at a current value of 0.2 CmA (100 mA) in an environment of 20 ° C.
0.2 CmA (100 mA) in an environment of -20 ° C
Table 1 shows the results of calculating the discharge capacity ratio when discharging was performed to 3.0 V at the current value of.
【００３５】[0035]
【表１】 [Table 1]
【００３６】表１から４００サイクル後の放電容量維持
率や−２０℃の極低温における放電容量比率が高いこと
が明らかになった。これは、第２の可塑剤であるＥＭ
Ｃ、ＤＭＣなどの低沸点カーボネートによる１００ｎｍ
未満の細孔がポリマーの結晶化を防止する効果により、
電解液／ポリマー量の倍率が４倍以上にすることがで
き、多量かつ均一に非水系電解液を含有させることがで
きるためである。Table 1 shows that the discharge capacity retention ratio after 400 cycles and the discharge capacity ratio at an extremely low temperature of -20 ° C. are high. This is because the second plasticizer, EM
100nm by low boiling point carbonate such as C and DMC
Due to the effect that less pores prevent crystallization of the polymer,
This is because the ratio of the amount of the electrolyte / polymer can be 4 times or more, and the nonaqueous electrolyte can be contained in a large amount and uniformly.
【００３７】[0037]
【発明の効果】以上のように本発明は、有機溶媒に可溶
性でかつポリマーと非溶解性の第１の可塑剤とポリマー
膨潤性のある第２の可塑剤を少なくとも２種類用いるこ
とにより、正極および／または負極の電極合剤内部にそ
の大きさが１００ｎｍから１０μｍの非水電解液を吸収
保持する第１の細孔と、その大きさが１００ｎｍ未満の
ゲルマトリックスを構築する第２の細孔との両方を具備
した構成からなる。１００ｎｍ以下の第２の細孔が存在
するため、従来よりも、多量かつ均一に非水系電解液を
含有することができるため電池特性、信頼性に優れたポ
リマー電解質二次電池を提供することができる。As described above, the present invention provides a positive electrode by using at least two kinds of a first plasticizer which is soluble in an organic solvent and is insoluble in a polymer and a second plasticizer which has a polymer swelling property. And / or a first pore for absorbing and holding a non-aqueous electrolyte having a size of 100 nm to 10 μm inside an electrode mixture of a negative electrode, and a second pore for constructing a gel matrix having a size of less than 100 nm. ). Since the second pores having a diameter of 100 nm or less are present, the nonaqueous electrolyte solution can be contained in a larger amount and more uniformly than before, so that a polymer electrolyte secondary battery having excellent battery characteristics and reliability can be provided. it can.
【図１】本発明の一実施形態における電池の上面図FIG. 1 is a top view of a battery according to an embodiment of the present invention.
【図２】同電池の断面図FIG. 2 is a sectional view of the battery.
１ 正極 １ａ 正極集電体 １ｂ 正極活物質層 １Ｃ 正極リード取り付け部 ２ 負極 ２ａ 負極集電体 ２ｂ 負極活物質層 ２Ｃ 負極リード取り付け部 ３ セパレータ ４ 発電要素 ５ 正極リード ６ 負極リード ７ 外装ケース ８ 正極出力端子 ９ 負極出力端子 １０ 正極リード絶縁保護フィルム １１ 負極リード絶縁保護フィルム Ｐ１ 外装ケース熱溶着部 Ｐ２ 外装ケース熱溶着部 Ｐ３ 外装ケース熱溶着部 Ｔ 外装ケース折り曲げ部 DESCRIPTION OF SYMBOLS 1 Positive electrode 1a Positive electrode current collector 1b Positive electrode active material layer 1C Positive electrode lead attachment part 2 Negative electrode 2a Negative electrode current collector 2b Negative electrode active material layer 2C Negative lead attaching part 3 Separator 4 Power generation element 5 Positive electrode lead 6 Negative electrode lead 7 Outer case 8 Positive electrode Output terminal 9 Negative electrode output terminal 10 Positive electrode lead insulating protective film 11 Negative electrode lead insulating protective film P1 Outer case heat welded part P2 Outer case heat welded part P3 Outer case heat welded part T Outer case bent part
───────────────────────────────────────────────────── フロントページの続き (72)発明者 峯谷 邦彦 大阪府門真市大字門真1006番地 松下電器 産業株式会社内 Ｆターム(参考） 5H029 AJ05 AK03 AL06 AL07 AM01 AM02 AM03 AM07 AM11 AM16 BJ04 CJ02 CJ03 CJ06 CJ08 CJ22 DJ12 DJ13 HJ01 HJ06 HJ14 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kunihiko Minegiya 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture F-term in Matsushita Electric Industrial Co., Ltd. 5H029 AJ05 AK03 AL06 AL07 AM01 AM02 AM03 AM07 AM11 AM16 BJ04 CJ02 CJ03 CJ06 CJ08 CJ22 DJ12 DJ13 HJ01 HJ06 HJ14
Claims (9)
正極とリチウムイオンを吸蔵、放出が可能な炭素質材料
を活物質とする負極及び非水系電解液を吸収保持するポ
リマーゲル電解質からなるポリマー電解質二次電池にお
いて、前記正極および／または負極の電極合材中に非水
系電解液を吸収保持するためのポリマーが、大きさの異
なる少なくとも２種類以上の細孔を具備することを特徴
とするポリマー電解質二次電池。1. A polymer comprising a positive electrode having a lithium-containing composite oxide as an active material, a negative electrode having a carbonaceous material capable of occluding and releasing lithium ions as an active material, and a polymer gel electrolyte absorbing and retaining a non-aqueous electrolyte. In the electrolyte secondary battery, the polymer for absorbing and retaining the nonaqueous electrolyte in the electrode mixture of the positive electrode and / or the negative electrode has at least two or more types of pores having different sizes. Polymer electrolyte secondary battery.
満の細孔を具備することを特徴とする請求項１に記載の
ポリマー電解質二次電池。2. The polymer electrolyte secondary battery according to claim 1, wherein the pores have pores having a size of less than 100 nm.
ら１０μｍの第１の細孔と１００ｎｍ未満の第２の細孔
を具備することを特徴とする請求項１に記載のポリマー
電解質二次電池。3. The polymer electrolyte secondary according to claim 1, wherein the pores include a first pore having a size of 100 nm to 10 μm and a second pore having a size of less than 100 nm. battery.
含有される非水系電解液の割合がポリマーの質量に対し
て４倍以上であることを特徴とする請求項１に記載のポ
リマー電解質二次電池。4. The polymer electrolyte according to claim 1, wherein the ratio of the non-aqueous electrolyte contained in the electrode mixture of the positive electrode and / or the negative electrode is at least four times the mass of the polymer. Rechargeable battery.
とポリマーと可塑剤を混練分散させてペーストを作製
し、集電体上に塗布、乾燥、圧延する正極工程と、リチ
ウムイオンを吸蔵、放出が可能な炭素質材料からなる活
物質とポリマーと可塑剤とを混練分散させてペーストを
作製し、集電体上に塗布、乾燥、圧延する負極工程と、
これらをセパレータを介して一体化し、外装ケースに挿
入する工程からなる製造方法において、正極工程および
／または負極工程における可塑剤は、有機溶媒に可溶性
でかつポリマーと非溶解性の第１の可塑剤と、ポリマー
膨潤性のある第２の可塑剤からなることを特徴とするポ
リマー電解質二次電池の製造方法。5. A positive electrode step in which an active material comprising a lithium-containing composite oxide, a polymer and a plasticizer are kneaded and dispersed to prepare a paste, applied on a current collector, dried and rolled, and occlusion and release of lithium ions A negative electrode step of preparing a paste by kneading and dispersing an active material composed of a carbonaceous material, a polymer, and a plasticizer, applying the paste on a current collector, drying and rolling,
In a manufacturing method comprising the steps of integrating these via a separator and inserting them into an outer case, the plasticizer in the positive electrode step and / or the negative electrode step is a first plasticizer that is soluble in an organic solvent and insoluble in a polymer. And a polymer plastic swellable second plasticizer.
トであることを特徴とする請求項５に記載のポリマー電
解質二次電池の製造方法。6. The method according to claim 5, wherein the second plasticizer is a low-boiling carbonate.
を有することを特徴とする請求項５または請求項６に記
載のポリマー電解質二次電池の製造方法。7. The method for producing a polymer electrolyte secondary battery according to claim 5, wherein the second plasticizer has a boiling point of 130 ° C. or less.
ネート（ＥＭＣ）、ジエチルカーボネート（ＤＥＣ）、
ジメチルカーボネート（ＤＭＣ）から選ばれた１種以上
であることを特徴とする請求項５乃至請求項７のいずれ
かに記載のポリマー電解質二次電池の製造方法。8. The method according to claim 1, wherein the second plasticizer is ethyl methyl carbonate (EMC), diethyl carbonate (DEC),
The method for producing a polymer electrolyte secondary battery according to any one of claims 5 to 7, wherein the method is at least one selected from dimethyl carbonate (DMC).
（ＤＢＰ）であることを特徴とする請求項５に記載のポ
リマー電解質二次電池の製造方法。9. The method for producing a polymer electrolyte secondary battery according to claim 5, wherein the first plasticizer is dibutyl phthalate (DBP).
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110224180A (en) * | 2019-04-30 | 2019-09-10 | 河北神州巨电新能源科技开发有限公司 | A kind of extraction process of new polymers lithium battery |
| CN112331912A (en) * | 2020-11-09 | 2021-02-05 | 贵州梅岭电源有限公司 | Preparation method of gel electrolyte |
-
2000
- 2000-03-30 JP JP2000093165A patent/JP2001283912A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110224180A (en) * | 2019-04-30 | 2019-09-10 | 河北神州巨电新能源科技开发有限公司 | A kind of extraction process of new polymers lithium battery |
| CN112331912A (en) * | 2020-11-09 | 2021-02-05 | 贵州梅岭电源有限公司 | Preparation method of gel electrolyte |
| CN112331912B (en) * | 2020-11-09 | 2021-12-21 | 贵州梅岭电源有限公司 | Preparation method of gel electrolyte |
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