JP2009206006A - Manufacturing method of electrochemical device, and electrochemical device - Google Patents

Manufacturing method of electrochemical device, and electrochemical device Download PDF

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JP2009206006A
JP2009206006A JP2008049076A JP2008049076A JP2009206006A JP 2009206006 A JP2009206006 A JP 2009206006A JP 2008049076 A JP2008049076 A JP 2008049076A JP 2008049076 A JP2008049076 A JP 2008049076A JP 2009206006 A JP2009206006 A JP 2009206006A
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heat
power storage
electrochemical device
laminate
shrinkable film
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Masanori Yoshida
雅憲 吉田
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Panasonic Corp
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Panasonic Corp
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    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10Energy storage using batteries
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02PCLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50Manufacturing or production processes characterised by the final manufactured product

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Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that in a conventional manufacturing method in which a laminate is wound with thermal-shrinking film and the thermal-shrinking film is thermally shrunk, spaces are produced between a positive electrode and a separator or an electrolyte layer and between a negative electrode and the separator or the electrolyte layer near the central portion of the laminate. <P>SOLUTION: In the manufacturing method of the electrochemical device, a laminate 1 in which a separator 13 is pinched with a positive electrode 11 and a negative electrode 12 is made, and a power storage body 2 is made so that a thermal-shrinking film 6 can be an outermost layer of the laminate 1, and a central portion of a body plane surface of the power storage body 2 is hot-pressed and a part of the thermal-shrinking film in the outermost layer is shrunk. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

本発明は、薄型の電気化学デバイス、特にリチウム二次電池に適用するのに好適な蓄電デバイスとその製造方法とに関するものである。   The present invention relates to an electricity storage device suitable for application to a thin electrochemical device, particularly a lithium secondary battery, and a method for producing the same.

近年、携帯機器等の電子機器の発展に伴い、電子機器に対する高機能化および薄型化のニーズが高まっている。電子機器の電源に用いられる電気化学デバイス、特にリチウム二次電池に対しても、更なる高容量化、高安全化、低抵抗化によるハイレート化、薄型化が求められている。   In recent years, along with the development of electronic devices such as portable devices, there is an increasing need for high functionality and thinning of electronic devices. Electrochemical devices used as power sources for electronic devices, particularly lithium secondary batteries, are also required to have higher capacities, higher safety, higher rates and lower thicknesses by lowering resistance.

従来、一般的な薄型電池としては、例えば正極、セパレータ及び負極の積層体よりなる蓄電体をラミネートフィルムで被包し、各層同士の密着性を高めるためにラミネート外装材の内部を減圧し、蓄電要素に対し積層方向の圧迫力を加えたものが考案されている(例えば、特許文献1参照)。   Conventionally, as a general thin battery, for example, a power storage body composed of a laminate of a positive electrode, a separator, and a negative electrode is encapsulated with a laminate film, and the inside of the laminate exterior material is depressurized in order to improve the adhesion between the layers. An element in which a pressing force in the stacking direction is applied to an element has been devised (for example, see Patent Document 1).

さらに、長期にわたる圧迫力の維持の向上を目的として、積層された平板状の電極(正極及び負極)と電解質層とを有する集電体を構成する蓄電要素において、熱収縮フィルムによりこの積層体を取り巻き、熱収縮フィルムを熱収縮させるという簡便な製造方法で、各層の密着性を高めることが考案されている(例えば、特許文献2参照)。
特開平8−83596号公報 特開2000−311717号公報
Further, for the purpose of improving the maintenance of the compression force over a long period of time, in a power storage element constituting a current collector having a laminated plate-like electrode (positive electrode and negative electrode) and an electrolyte layer, the laminate is formed by a heat shrink film. It has been devised to improve the adhesion of each layer by a simple manufacturing method of enclosing and heat-shrinking a heat-shrinkable film (for example, see Patent Document 2).
JP-A-8-83596 JP 2000-311717 A

しかしながら、熱収縮フィルムにより積層体を取り巻き、熱収縮フィルムを熱収縮させる製造方法では、熱収縮性フィルム全体に熱をかけ収縮させているので、積層体の外側よりも中央部付近での圧迫力が小さくなりやすく、その中央部付近で正極とセパレータまたは電解質層間、負極とセパレータまたは電解質層間に隙間を発生させる場合がある。   However, in the manufacturing method in which the laminate is surrounded by the heat-shrinkable film and the heat-shrinkable film is heat-shrinked, the entire heat-shrinkable film is shrunk by applying heat, so the compression force is closer to the center than the outside of the laminate. In some cases, a gap is generated between the positive electrode and the separator or the electrolyte layer and between the negative electrode and the separator or the electrolyte layer near the center.

上記課題を解決するために、本発明は、正極と負極とを、セパレータおよび電解質層の少なくとも一つで挟持して積層体を作成する工程(a)と、前記積層体の最外層に熱収縮性フィルムを配置して蓄電体を作製する工程(b)と、前記蓄電体の胴体平面の中央部を熱プレスして、前記熱収縮フィルムの一部を収縮させる工程(c)とを含む電気化学デバイスの製造方法とする。   In order to solve the above problems, the present invention includes a step (a) of forming a laminate by sandwiching a positive electrode and a negative electrode with at least one of a separator and an electrolyte layer, and heat shrinkage to the outermost layer of the laminate Including a step (b) of producing a power storage unit by disposing a conductive film, and a step (c) of contracting a part of the heat-shrinkable film by hot pressing a central portion of a body plane of the power storage unit. Let it be a manufacturing method of a chemical device.

本発明の電気化学デバイスの製造方法によれば、蓄電体の胴体平面の中央部熱収縮性フィルムを熱プレスすることにより、蓄電体の胴体平面の中央部に位置する熱収縮性フィルムの剛性を、熱プレスされていない部分より大きくできるので、蓄電体の外側よりも中央部付近の圧迫力を大きくできる。その結果、蓄電体の外側よりも中央部付近を膨れにくくできるので、蓄電要素の中央部付近ほど隙間が開きやすいという課題を解決できる。さらには、熱プレスという簡便な方法で提供できる。   According to the method for manufacturing an electrochemical device of the present invention, the heat shrinkable film located at the center of the body plane of the power storage unit is heated by pressing the heat shrinkable film at the center of the body plane of the power storage unit. Since it can be made larger than the portion that is not hot-pressed, the pressing force near the center can be made larger than the outside of the power storage unit. As a result, the vicinity of the central portion can be more difficult to swell than the outside of the power storage unit, so that the problem that the gap is likely to open near the central portion of the power storage element can be solved. Furthermore, it can be provided by a simple method called hot pressing.

以下、本発明を実施するための最良の形態を、図面を参照しながら説明する。なお、本発明は、以下の内容に限定されない。   Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings. The present invention is not limited to the following contents.

(実施の形態1)
図1は、本発明の実施の形態1における電気化学デバイスの一例となるリチウム二次電池の蓄電体2の斜視図である。蓄電体2は、正極集電体4、負極集電体5を備えた積層体1の最外層となる外層部に、熱収縮フィルム6を巻き付けて構成されている。図2は、蓄電体2を正極集電体4、負極集電体5を備える側面から見た外観図、図3は、蓄電体2を胴体部から見た外観図である。図4は、図3における蓄電体2のX−X断面図である。図4に示されるように、蓄電体2を構成する積層体1は、正極11と負極12とをセパレータ13で挟持して構成されている。また、積層体1の最外層となる外層部に配置した熱収縮フィルム6は、蓄電体2の胴体平面の中央部に、熱プレスにより収縮が生じた熱プレス痕10を有している。なお、図1および図3に示されるように、熱プレス痕10は、蓄電体2の胴体部の中央部に楕円形状に構成されている(図1および図3では、熱プレス痕10の範囲がわかりやすいように、その範囲を実線で記載)。
(Embodiment 1)
FIG. 1 is a perspective view of a power storage unit 2 of a lithium secondary battery, which is an example of an electrochemical device according to Embodiment 1 of the present invention. The power storage unit 2 is configured by winding a heat-shrinkable film 6 around an outer layer portion that is the outermost layer of the laminate 1 including the positive electrode current collector 4 and the negative electrode current collector 5. FIG. 2 is an external view of the power storage unit 2 as viewed from the side including the positive electrode current collector 4 and the negative electrode current collector 5, and FIG. 3 is an external view of the power storage unit 2 as viewed from the body. 4 is an XX cross-sectional view of the power storage unit 2 in FIG. As shown in FIG. 4, the stacked body 1 constituting the power storage unit 2 is configured by sandwiching a positive electrode 11 and a negative electrode 12 with a separator 13. In addition, the heat shrinkable film 6 disposed in the outer layer portion that is the outermost layer of the laminated body 1 has a heat press mark 10 in which the shrinkage occurs due to heat press at the center of the body plane of the power storage unit 2. As shown in FIGS. 1 and 3, the hot press mark 10 is configured in an elliptical shape at the center of the body part of the power storage unit 2 (in FIGS. 1 and 3, the range of the hot press mark 10 is The range is indicated by a solid line to make it easier to understand.)

図5に、熱収縮フィルム6に熱プレスを行わず全体を熱収縮させた蓄電体2の断面図を示す。本実施の形態1の蓄電体2と比較すると、熱収縮性フィルム6全体に熱をかけ収縮させているので、積層体1の外側よりも中央部付近の圧迫力が小さくなりやすく、その中央部付近で正極11とセパレータ13、および負極12とセパレータ13間に、若干の隙間が生じていることがわかる。一方、本実施の形態1の蓄電体2では、蓄電体2の胴体平面の中央部の熱収縮性フィルム6を熱プレスすることにより、蓄電体2の胴体平面の中央部に位置する熱収縮性フィルム6の剛性を、熱プレスされていない部分より大きくできる。その結果、蓄電体2の外側よりも中央部付近の圧迫力を大きくでき、蓄電体2の外側よりも中央部付近での膨れを生じさせにくくできていることがわかる。   FIG. 5 shows a cross-sectional view of the power storage unit 2 in which the entire heat-shrinkable film 6 is heat-shrinked without being hot-pressed. Compared with the power storage unit 2 of the first embodiment, the entire heat-shrinkable film 6 is shrunk by applying heat, so that the compression force near the center portion tends to be smaller than the outer side of the laminate 1, and the center portion It can be seen that there are slight gaps between the positive electrode 11 and the separator 13 and between the negative electrode 12 and the separator 13 in the vicinity. On the other hand, in the power storage unit 2 of the first embodiment, the heat-shrinkable film 6 located at the center of the body plane of the power storage unit 2 is hot-pressed on the heat-shrinkable film 6 at the center of the body plane of the power storage unit 2. The rigidity of the film 6 can be made larger than the portion that is not hot-pressed. As a result, it can be seen that the pressing force in the vicinity of the central portion can be made larger than the outside of the power storage unit 2, and the swelling in the vicinity of the central portion can be made less likely to occur than the outside of the power storage unit 2.

次に、本発明の実施の形態1における電気化学デバイスの製造工程を、図6に示す製造工程図に基づき、および図1から4を参照しながら説明する。   Next, the manufacturing process of the electrochemical device according to the first embodiment of the present invention will be described based on the manufacturing process diagram shown in FIG. 6 and with reference to FIGS.

〈前工程〉
前工程では、正極11および負極12を作成する。具体的には、正極11および負極12を、基板に正極活物質および負極活物質を塗布して作成する。
<pre-process>
In the previous step, the positive electrode 11 and the negative electrode 12 are prepared. Specifically, the positive electrode 11 and the negative electrode 12 are formed by applying a positive electrode active material and a negative electrode active material to a substrate.

なお、本実施の形態1では、電気化学デバイスとしてリチウム二次電池を作成するため、正極11は、アルミニウム箔の表面にリチウムコバルト複合酸化物等の正極活物質を塗布したもの、負極12は、方形の銅箔の表面にカーボン等の負極活物質を塗布したものとした。なお、正極集電体4を接続固定するために、長手方向の一方の端部に、この正極活物質を塗布しない正極引出部、負極集電体5を接続固定するために、長手方向の他方の端部にこの負極活物質を塗布しない負極引出部が設けられている。   In the first embodiment, in order to create a lithium secondary battery as an electrochemical device, the positive electrode 11 is obtained by applying a positive electrode active material such as lithium cobalt composite oxide on the surface of an aluminum foil, and the negative electrode 12 is A negative electrode active material such as carbon was applied to the surface of a rectangular copper foil. In addition, in order to connect and fix the positive electrode current collector 4, the other end in the longitudinal direction is used to connect and fix the positive electrode lead portion not coated with the positive electrode active material and the negative electrode current collector 5 at one end in the longitudinal direction. The negative electrode lead-out part which does not apply | coat this negative electrode active material is provided in the edge part of this.

また、本発明による正極活物質のリチウム含有遷移金属酸化物としては、ニッケル酸リチウムや、コバルト酸リチウムなどのリチウム含有遷移金属酸化物、およびその固溶体等、Li(1−y)で表される化合物を用いることができる。なお、元素Mは、NiおよびCoよりなる群から選択される少なくとも1種である。元素Lは、アルカリ土類金属元素、NiおよびCo以外の遷移元素、希土類元素、IIIb族元素、およびIVb族元素からなる群から選択される少なくとも1種を含む。また、元素Lは、Al、Mn、Ti、Mg、Zr、Nb、Mo、W、およびYからなる群から選択される少なくとも1種を含むことが好ましい。それらの元素は、単独で含まれてもよく、2種以上を含んでいても良い。さらには、元素Lは、Mnなどの遷移元素にすることが望ましい。リチウム含有遷移金属酸化物の調製方法は、所定の金属元素比の酸化物、または水酸化物を酸化雰囲気
中で焼成することにより合成することができる。また、xおよびyの値は、0.85≦x≦1.25、かつ、0≦y≦0.50を満たすことが望ましい。特に、リチウム含有量を表すxの値は、電池の充放電により増減するが、完全放電状態や、電池組立直後の初期状態、もしくはリチウム複合酸化物の合成直後において、0.85≦x≦1.35であればよく、さらには1.02≦x≦1.25が好ましい。さらに、正極11の電気化学的特性やサイクル特性を向上させるため、人造黒鉛、天然黒鉛、繊維状カーボンやカーボンブラックなどの導電剤、ポリフッ化ビニリデンやポリテトラフルオロエチレンなどの結着剤を、正極活物質とともに用いても良い。
In addition, examples of the lithium-containing transition metal oxide of the positive electrode active material according to the present invention include lithium-containing transition metal oxides such as lithium nickelate and lithium cobaltate, and solid solutions thereof such as Li x M (1-y) L y. A compound represented by O 2 can be used. The element M is at least one selected from the group consisting of Ni and Co. The element L includes at least one selected from the group consisting of alkaline earth metal elements, transition elements other than Ni and Co, rare earth elements, IIIb group elements, and IVb group elements. The element L preferably contains at least one selected from the group consisting of Al, Mn, Ti, Mg, Zr, Nb, Mo, W, and Y. These elements may be contained alone or in combination of two or more. Furthermore, the element L is preferably a transition element such as Mn. The method for preparing a lithium-containing transition metal oxide can be synthesized by firing an oxide or hydroxide having a predetermined metal element ratio in an oxidizing atmosphere. The values of x and y desirably satisfy 0.85 ≦ x ≦ 1.25 and 0 ≦ y ≦ 0.50. In particular, the value of x representing the lithium content increases or decreases depending on the charge / discharge of the battery, but 0.85 ≦ x ≦ 1 in the fully discharged state, the initial state immediately after the battery assembly, or immediately after the synthesis of the lithium composite oxide. .35, and 1.02 ≦ x ≦ 1.25 is more preferable. Furthermore, in order to improve the electrochemical characteristics and cycle characteristics of the positive electrode 11, a conductive agent such as artificial graphite, natural graphite, fibrous carbon and carbon black, and a binder such as polyvinylidene fluoride and polytetrafluoroethylene are used. You may use with an active material.

また、負極12を構成する基板は、銅やニッケルなどの厚さ5μmから50μmの箔が用いることができるが、電解銅箔など表面があらかじめ粗面化されているものが、絶縁物との密着性向上、負極活物質との接触抵抗低減の観点から好ましい。なお、負極活物質は、リチウム二次電池用途の公知の材料を用いることができるが、好ましくは、Liを吸蔵放出可能な黒鉛や非晶質炭素、Liと合金化することが可能なSn、Si、SiOなどの化合物が挙げることができる。さらに、負極12の電気化学的特性やサイクル特性を向上させるため、人造黒鉛、天然黒鉛、繊維状カーボンやカーボンブラックなどの導電剤、ポリフッ化ビニリデンなどの結着剤を、負極活物質とともに用いても良い。   Further, the substrate constituting the negative electrode 12 can be made of a foil having a thickness of 5 μm to 50 μm such as copper or nickel, but the one having a roughened surface such as an electrolytic copper foil is in close contact with the insulator. It is preferable from the viewpoint of improving the property and reducing the contact resistance with the negative electrode active material. As the negative electrode active material, a known material for lithium secondary battery applications can be used. Preferably, graphite or amorphous carbon capable of occluding and releasing Li, Sn capable of being alloyed with Li, Examples thereof include compounds such as Si and SiO. Furthermore, in order to improve the electrochemical characteristics and cycle characteristics of the negative electrode 12, a conductive agent such as artificial graphite, natural graphite, fibrous carbon and carbon black, and a binder such as polyvinylidene fluoride are used together with the negative electrode active material. Also good.

なお、正極11および負極12への正極活物質または負極活物質の形成は、塗工だけでなく、蒸着、スパッタ、エアロゾルデポジション法等の公知の形成方法も選択できる。   In addition, formation of the positive electrode active material or the negative electrode active material to the positive electrode 11 and the negative electrode 12 can select not only coating but well-known formation methods, such as vapor deposition, a sputtering, and an aerosol deposition method.

〈工程(a):集積体1を作成する〉
次に、前工程で作成した正極11と負極12とを、セパレータ13で挟持して積層体1を作成する。なお、積層数が多い場合、負極12は、正極11を挟んだセパレータ13の間とその上下に配置される。また、セパレータ13は、正極11および負極12が接触短絡しないように、正極11および負極12よりわずかに大きな面積を有するものが望ましい。また、正極11の正極引出部と負極12の負極引出部は、積層体1の片側からそれぞれ突出するように構成するのが望ましい。
<Step (a): Creating the Aggregate 1>
Next, the laminated body 1 is produced by sandwiching the positive electrode 11 and the negative electrode 12 created in the previous step with a separator 13. When the number of stacked layers is large, the negative electrode 12 is disposed between and above and below the separator 13 with the positive electrode 11 interposed therebetween. The separator 13 preferably has a slightly larger area than the positive electrode 11 and the negative electrode 12 so that the positive electrode 11 and the negative electrode 12 do not contact short-circuit. Further, it is desirable that the positive electrode lead portion of the positive electrode 11 and the negative electrode lead portion of the negative electrode 12 are configured to protrude from one side of the laminate 1.

本実施の形態で1では、セパレータ13として、ポリエチレンシートに耐熱性の高いポリプロピレンシートをラミネートし、延伸加工により微多孔膜としたものを用いた。なお、セパレータ13には、一般的に、イオン透過度が大きく、所定の機械的強度を持つ、絶縁性の微多孔性薄膜が用いられ、例えば、ポリプロピレン、ポリエチレンなどの単独又は組み合わせたポリオレフィン系ポリマー、ポリアラミド系ポリマーやガラス繊維などで構成されたシートや不織布が用いられる。また、セパレータ13における微多孔の孔径は、正極11や負極12から脱離した活物質、結着剤、導電剤を透過させない大きさが望ましく、例えば、0.01〜1μmであるものが望ましい。また、一般的にセパレータ13の厚みは、イオン透過性を考慮して5〜300μmのものが用いられる。なお、セパレータ13の空孔率は、電子やイオンの透過性と素材や膜の突き刺し強度に応じて決定されるが、一般的に、20〜90%であることが望ましい。また、セパレータ13は、複数の単層膜を積層した多層膜でもよい。多層膜の場合、電池の安全性を高める上で、120〜150℃でいわゆるシャットダウン機能を発現させることが望ましい。120℃より低温でシャットダウン機能が作動する場合、高温保存時に電池機能を消失する危険があり、150℃より高温でシャットダウン機能が作動する場合、電池の熱暴走反応を抑止できなくなる危険が生じる可能性があるためである。なお、120〜150℃の温度範囲でシャットダウン機能を発現させるには、120〜150℃の温度範囲で溶融するポリエチレンを主成分とした単層膜を含めることが望ましい。さらに、電池の耐熱安全性を高めるために、SiOやAlといった無機物を主体とした単層膜を含めることもできる。 In the first embodiment, the separator 13 is a polyethylene sheet laminated with a polypropylene sheet having high heat resistance and made into a microporous film by stretching. The separator 13 is generally an insulating microporous thin film having a high ion permeability and a predetermined mechanical strength. For example, a single or combined polyolefin polymer such as polypropylene or polyethylene. Sheets and nonwoven fabrics composed of polyaramid polymers or glass fibers are used. In addition, the microporous pore size in the separator 13 is desirably a size that does not allow the active material, the binder, and the conductive agent detached from the positive electrode 11 and the negative electrode 12 to permeate, for example, 0.01 to 1 μm. In general, the separator 13 has a thickness of 5 to 300 μm in consideration of ion permeability. The porosity of the separator 13 is determined in accordance with the permeability of electrons and ions and the piercing strength of the material and the film, but is generally preferably 20 to 90%. The separator 13 may be a multilayer film in which a plurality of single layer films are stacked. In the case of a multilayer film, it is desirable to develop a so-called shutdown function at 120 to 150 ° C. in order to increase the safety of the battery. When the shutdown function operates at a temperature lower than 120 ° C, there is a risk that the battery function may be lost during high temperature storage, and when the shutdown function operates at a temperature higher than 150 ° C, there is a risk that the thermal runaway reaction of the battery cannot be suppressed. Because there is. In order to develop the shutdown function in the temperature range of 120 to 150 ° C., it is desirable to include a single layer film mainly composed of polyethylene that melts in the temperature range of 120 to 150 ° C. Furthermore, a single layer film mainly composed of an inorganic material such as SiO 2 or Al 2 O 3 can be included in order to improve the heat resistance and safety of the battery.

なお、電気化学デバイスに用いる電解質層が固体であり、セパレータ13が不要な場合
は、電解質層で正極11と負極12とを挟持して積層体1を作成する。また、電解質層が固体であり、セパレータ13と併用する場合、電解質層とセパレータ13で正極11と負極12とを挟持して積層体1を作成する工程となる。
In addition, when the electrolyte layer used for an electrochemical device is solid and the separator 13 is unnecessary, the positive electrode 11 and the negative electrode 12 are pinched | interposed with an electrolyte layer, and the laminated body 1 is created. In addition, when the electrolyte layer is solid and is used in combination with the separator 13, the laminate 1 is formed by sandwiching the positive electrode 11 and the negative electrode 12 between the electrolyte layer and the separator 13.

〈工程(b):蓄電体2を作成する〉
次に、工程(a)で作成した積層体1の最外層に、熱収縮性フィルム6を配置して蓄電体2を作製する。具体的には、図2に示すように、積層体1の最外層の外周部となる胴体部分を熱収縮フィルム6で巻く。なお、本実施の形態1に示すように、積層体1の胴体部分を熱収縮性フィルム6で巻くことによって、積層体1の位置ずれを小さくできる効果が得られる。
<Step (b): Creating power storage unit 2>
Next, the heat-shrinkable film 6 is arrange | positioned in the outermost layer of the laminated body 1 created at the process (a), and the electrical storage body 2 is produced. Specifically, as shown in FIG. 2, the body portion that is the outer peripheral portion of the outermost layer of the laminate 1 is wound with a heat shrink film 6. In addition, as shown in this Embodiment 1, the effect that the position shift of the laminated body 1 can be made small by winding the trunk | drum part of the laminated body 1 with the heat-shrinkable film 6 is acquired.

なお、熱収縮フィルム6は、熱収縮性を有する素材であれば構わないが、好ましくは、ポリエチレン、ポリプロピレン、変性ポリオレフィンなどを用いることができる。例えば、少なくともポリエチレンまたは/かつポリプロピレンを含む多孔体とすることで、様々な酸化還元電位に対して比較的安定で、かつフィルムの強度が得られる。特に、リチウム二次電池の場合、信頼性、安全性を高めることができる。また、熱収縮フィルム6の厚さは、10〜50μm程度が好ましい。また、熱収縮フィルム6は、100〜200℃、特に100〜150℃で収縮し、さらには溶融して熱収縮フィルム6同士が接着するものが好ましい。なお、熱収縮性フィルム6をセパレータ13と同様な材料とすることで、低コスト化を図ることもできる。   The heat-shrinkable film 6 may be any material having heat-shrinkability, but preferably, polyethylene, polypropylene, modified polyolefin, or the like can be used. For example, by using a porous body containing at least polyethylene or / and polypropylene, it is relatively stable with respect to various oxidation-reduction potentials and film strength can be obtained. In particular, in the case of a lithium secondary battery, reliability and safety can be improved. Further, the thickness of the heat shrink film 6 is preferably about 10 to 50 μm. The heat shrinkable film 6 is preferably one that shrinks at 100 to 200 ° C., particularly 100 to 150 ° C., and further melts and adheres to each other. In addition, cost reduction can also be achieved by making the heat-shrinkable film 6 into the material similar to the separator 13. FIG.

〈工程(c):蓄電体2を熱プレスする〉
次に、工程(b)で作成した蓄電体2を熱プレスする。熱プレスは、一般的に用いられている熱プレス機を用い、蓄電体2(積層体1)の胴体平面部分の中央部を熱プレスして、熱収縮フィルム6の一部を収縮させる。この時、図4に示されるように、熱収縮フィルム6が熱プレスされ収縮剛体化され、熱プレス痕10となる。なお、熱プレスは、胴体平面部分のできるだけ中央部に近い箇所に行うことが好ましい。これは、積層体1の胴体部分の外側より中央部を収縮させることで、蓄電要素の中央部付近の隙間を小さくできるからである。
<Step (c): Hot pressing the power storage unit 2>
Next, the power storage unit 2 created in the step (b) is hot pressed. In the hot press, a heat press machine generally used is used, and the central portion of the body plane portion of the power storage unit 2 (laminated body 1) is hot pressed to shrink a part of the heat shrinkable film 6. At this time, as shown in FIG. 4, the heat-shrinkable film 6 is hot-pressed to be made into a shrink-rigid body and become a heat-pressed mark 10. In addition, it is preferable to perform a hot press in the location close | similar to the center part as much as possible of the trunk | drum plane part. This is because the gap near the central portion of the power storage element can be reduced by shrinking the central portion from the outside of the body portion of the laminate 1.

なお、積層体1内部のセパレータ13を収縮させると、リチウム二次電池としての充放電特性を低下させる恐れがあるので、熱収縮フィルム6の収縮温度、融点が、セパレータ13の収縮温度、融点以下であるものを用いることが好ましい。これにより、熱収縮性フィルム6がセパレータ13の熱収縮温度より低くすることで、積層体1内部のセパレータ13を熱収縮させることなく、熱収縮フィルム6のみを熱収縮させることができる。   In addition, since shrinkage | contraction of the separator 13 inside the laminated body 1 may reduce the charging / discharging characteristic as a lithium secondary battery, the shrinkage temperature and melting | fusing point of the heat-shrinkable film 6 are below the shrinkage | contraction temperature and melting | fusing point of the separator 13. It is preferable to use what is. Thereby, only the heat-shrinkable film 6 can be heat-shrinked, without making the separator 13 inside the laminated body 1 heat-shrink by making the heat-shrinkable film 6 lower than the heat-shrinking temperature of the separator 13.

また、熱プレスの条件は、熱プレス温度が高温でプレス時間が短いほうが好ましい。例えば、熱収縮フィルム6とセパレータ13を同じ厚み20μmの多孔性ポリエチレンシートで実施した場合、熱プレス温度が180℃で、プレス時間が0.5秒以下の条件が好ましい。この条件で実施することにより巻き始めと巻き終わりの重なり合った2枚の熱収縮フィルム6を接着することができ、接着テープなしで積層体1を固定化することが可能で、生産性も向上する。   The hot pressing conditions are preferably that the hot pressing temperature is high and the pressing time is short. For example, when the heat-shrinkable film 6 and the separator 13 are implemented by a porous polyethylene sheet having the same thickness of 20 μm, the conditions that the hot press temperature is 180 ° C. and the press time is 0.5 seconds or less are preferable. By carrying out under these conditions, it is possible to bond the two heat-shrink films 6 at the start and end of winding, and it is possible to fix the laminate 1 without an adhesive tape, and the productivity is also improved. .

また、積層体1の胴体に巻かれた熱収縮フィルム6が重なり合った部分を、熱プレスすることが好ましい。これにより、積層体1に巻かれた熱収縮フィルム6同士が接着されて固定化されるので、巻き止め用接着テープなどを削減でき、生産性を向上することを可能とする。   Moreover, it is preferable to heat-press the part where the heat shrink film 6 wound around the trunk | drum of the laminated body 1 overlapped. Thereby, since the heat-shrink film 6 wound around the laminated body 1 is bonded and fixed, it is possible to reduce the anti-winding adhesive tape and improve productivity.

なお、本実施の形態1では、図2に示すように、熱プレス痕10が蓄電体2の胴体部の中央部に楕円形状に構成されように、熱プレスを行ったが、熱プレスは、蓄電体2の外側
より中央部ほど収縮剛体化するように行うことが好ましく、例えば、図7〜図9に示すような熱プレス痕10としても良い。なお、熱プレスの形状はこれに限定するものではない。
In the first embodiment, as shown in FIG. 2, the hot press is performed so that the hot press mark 10 is configured in an elliptical shape at the center of the body portion of the power storage unit 2. It is preferable to carry out the contraction rigid body from the outer side of the electric storage body 2 toward the center, and for example, a hot press mark 10 as shown in FIGS. The shape of the hot press is not limited to this.

〈後工程〉
次に、工程(c)で作成した蓄電体2を用いて、リチウム二次電池(電気化学デバイス)を作成する。具体的には、蓄電体2の正極引出部および負極引出部に端子を溶接した後、袋状または角型の外装体に入れ、電解液を真空含浸し、注液部を封止してリチウム二次電池を作成する。なお、リチウム二次電池では、正極に用いる端子はアルミニウムが好ましく、負極に用いる端子はニッケル、銅が好ましい。特に、アルミニウムは、表面に酸化皮膜を有しているため、酸化皮膜を陽極酸化法によって容易に厚くすることができるため、絶縁性を高めることが容易でかつ抵抗溶接などにより容易に低抵抗の接続を取りやすいために好ましい。
<Post-process>
Next, a lithium secondary battery (electrochemical device) is created using the power storage unit 2 created in the step (c). Specifically, after the terminals are welded to the positive electrode extraction portion and the negative electrode extraction portion of the power storage unit 2, they are put in a bag-shaped or rectangular outer package, vacuum-impregnated with an electrolytic solution, and the injection portion is sealed to form lithium. Create a secondary battery. In the lithium secondary battery, the terminal used for the positive electrode is preferably aluminum, and the terminal used for the negative electrode is preferably nickel or copper. In particular, since aluminum has an oxide film on its surface, the oxide film can be easily thickened by an anodic oxidation method. Therefore, it is easy to improve the insulation and low resistance by resistance welding or the like. It is preferable because it can be easily connected.

なお、電解液は、リチウム二次電池を作成する場合、非水電解液であり、非水溶媒と、その溶媒に溶解させたリチウム塩とから構成されている。非水溶媒としては、例えば、エチレンカーボネ−ト、プロピレンカーボネート、ブチレンカーボネート、ビニレンカーボネートなどの環状カーボネート類、ジメチルカーボネート、ジエチルカーボネート、エチルメチルカーボネート、ジプロピルカーボネートなどの非環状カーボネート類などを挙げることができ、これらの一種または二種以上を混合して使用する。特に、環状カーボネートと非環状カーボネートとの混合系を主成分とすることが好ましい。   In addition, when producing a lithium secondary battery, electrolyte solution is nonaqueous electrolyte solution, and is comprised from the nonaqueous solvent and the lithium salt dissolved in the solvent. Examples of the non-aqueous solvent include cyclic carbonates such as ethylene carbonate, propylene carbonate, butylene carbonate, and vinylene carbonate, and non-cyclic carbonates such as dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, and dipropyl carbonate. These may be used alone or in combination. In particular, it is preferable to use a mixed system of a cyclic carbonate and an acyclic carbonate as a main component.

これらの非水溶媒に溶解させるリチウム塩としては、例えば、LiClO4 、LiBF4 、LiPF6 、LiCF3SO3 、LiCF3 CO2 、Li(CFSO、LiN(CFSOなどを挙げることができ、これらを使用する電解液等に単独又は二種以上を組み合わせて使用することができる。特に、LiPF6 を含ませることが好ましい。 Examples of lithium salts to be dissolved in these non-aqueous solvents include LiClO 4 , LiBF 4 , LiPF 6 , LiCF 3 SO 3 , LiCF 3 CO 2 , Li (CF 3 SO 2 ) 2 , LiN (CF 3 SO 2 ). 2 and the like, and can be used alone or in combination of two or more kinds in an electrolyte solution using these. In particular, it is preferable to include LiPF 6 .

また、非水電解液を有機高分子に担持させたゲル電解質を用いることもできる。非水電解液を担持させる有機高分子としては、例えば、ポリエチレンオキサイド、ポリプロピレンオキサイド、ポリフッ化ビニリデン、ポリヘキサフルオロプロピレン、ポリアクリレート、ポリメタクリレートやこれらの誘導体などを挙げることができる。   A gel electrolyte in which a nonaqueous electrolytic solution is supported on an organic polymer can also be used. Examples of the organic polymer that supports the non-aqueous electrolyte include polyethylene oxide, polypropylene oxide, polyvinylidene fluoride, polyhexafluoropropylene, polyacrylate, polymethacrylate, and derivatives thereof.

また、外装体となる電池ケースは、AlやFe等の金属性の電池缶や金属箔の両面に樹脂フィルムをラミネートしたラミネートフィルムを袋状にしたものを用いることができるが、市場における電池の更なる薄型化や軽量化の要望に応えるためには、ラミネートフィルム製の電池ケースを用いることが好ましい。なお、電池の形状は、角形、薄型のいずれでもよい。以上のように、本実施の形態1に示す電気化学デバイスの製造方法は、積層体1の最外層に熱収縮フィルム6を配置して蓄電体2を作成し、蓄電体2の胴体平面の中央部を熱プレスするという簡便でかつ低コスト化が可能な生産性の高い製造方法でありながら、安全かつ信頼性の高い二次電池に提供できる。特に、二次電池の中でもより容量が大きく、反応の均一性が必要なリチウム二次電池の安全性と信頼性を高めることができる。   In addition, as a battery case as an outer package, a battery case made of a metal film such as Al or Fe or a laminate film obtained by laminating a resin film on both sides of a metal foil can be used. In order to meet demands for further reduction in thickness and weight, it is preferable to use a battery case made of a laminate film. The shape of the battery may be either square or thin. As described above, in the method for manufacturing an electrochemical device shown in the first embodiment, the heat shrink film 6 is arranged on the outermost layer of the laminate 1 to create the power storage unit 2, and the center of the body plane of the power storage unit 2 Although it is a simple and high-productivity manufacturing method capable of reducing the cost by hot pressing the part, it can be provided to a safe and reliable secondary battery. In particular, the safety and reliability of a lithium secondary battery that has a larger capacity and requires uniform reaction among the secondary batteries can be improved.

本発明は、多孔性熱収縮性フィルムを用いた積層構造の電気化学デバイスの製造と、その電気化学デバイス、例えば、高容量で優れた安全性をもつリチウム二次電池、電気化学キャパシタなど電気化学的メカニズムを利用するエネルギーデバイスに有用である。   The present invention relates to the production of an electrochemical device having a laminated structure using a porous heat-shrinkable film, and electrochemical devices such as lithium secondary batteries and electrochemical capacitors having high capacity and excellent safety. This is useful for energy devices that use mechanical mechanisms.

本発明の実施の形態1における蓄電体2を示す斜視図1 is a perspective view showing a power storage unit 2 according to Embodiment 1 of the present invention. 本発明の実施の形態1における蓄電要体2の外観図External view of power storage main body 2 in Embodiment 1 of the present invention 本発明の実施の形態1における蓄電要体2の外観図External view of power storage main body 2 in Embodiment 1 of the present invention 本発明の実施の形態1における蓄電要体2のX−X断面図XX sectional drawing of the electrical storage main body 2 in Embodiment 1 of this invention 従来の蓄電体2の断面図Sectional view of a conventional power storage unit 2 リチウム二次電池(電気化学デバイス)の製造工程図Manufacturing process diagram of lithium secondary battery (electrochemical device) 本発明の実施の形態1における熱プレス形状の一例を示す模式図Schematic diagram showing an example of a hot press shape in Embodiment 1 of the present invention 本発明の実施の形態1における熱プレス形状の一例を示す模式図Schematic diagram showing an example of a hot press shape in Embodiment 1 of the present invention 本発明の実施の形態1における熱プレス形状の一例を示す模式図Schematic diagram showing an example of a hot press shape in Embodiment 1 of the present invention

符号の説明Explanation of symbols

1 積層体
2 蓄電体
4 正極集電体
5 負極集電体
6 熱収縮フィルム
10 熱プレス痕
11 正極
12 負極
13 セパレータ
DESCRIPTION OF SYMBOLS 1 Laminated body 2 Electric power storage body 4 Positive electrode collector
5 Negative Electrode Current Collector 6 Heat Shrink Film 10 Hot Press Mark 11 Positive Electrode 12 Negative Electrode 13 Separator

Claims (7)

正極と負極とを、セパレータおよび電解質層の少なくとも一つで挟持して積層体を作成する工程(a)と、
前記積層体の最外層に熱収縮性フィルムを配置して蓄電体を作製する工程(b)と、
前記蓄電体の胴体平面の中央部を熱プレスして、前記熱収縮フィルムの一部を収縮させる工程(c)とを含む電気化学デバイスの製造方法。
A step of creating a laminate by sandwiching a positive electrode and a negative electrode with at least one of a separator and an electrolyte layer; and
A step (b) of producing a power storage unit by disposing a heat-shrinkable film on the outermost layer of the laminate;
A method of manufacturing an electrochemical device comprising: a step (c) in which a central portion of a body plane of the power storage unit is hot-pressed to shrink a part of the heat-shrinkable film.
前記工程(b)は、前記積層体の外周部に前記熱収縮性フィルムを巻く工程である
請求項1に記載の電気化学デバイスの製造方法。
The method for producing an electrochemical device according to claim 1, wherein the step (b) is a step of winding the heat-shrinkable film around an outer peripheral portion of the laminate.
前記工程(c)は、前記熱収縮フィルムが重なり合う部分を熱プレスする工程である
請求項2に記載の電気化学デバイスの製造方法。
The method for producing an electrochemical device according to claim 2, wherein the step (c) is a step of hot pressing a portion where the heat shrinkable film overlaps.
前記工程(c)は、熱プレスして前記積層体の中央部に位置する前記熱収縮フィルムを収縮させる工程である
請求項1から3に記載の電気化学デバイスの製造方法。
4. The method for producing an electrochemical device according to claim 1, wherein the step (c) is a step of heat-pressing and shrinking the heat-shrinkable film located at a central portion of the laminate.
前記請求項1から4に記載の製造方法で作製される電気化学デバイス。   An electrochemical device produced by the production method according to claim 1. 前記熱収縮性フィルムは、前記セパレータの熱収縮温度より低い材料で構成される
請求項5に記載の電気化学デバイス。
The electrochemical device according to claim 5, wherein the heat shrinkable film is made of a material lower than a heat shrink temperature of the separator.
前記熱収縮性フィルムは、ポリエチレンおよびポリプロピレンの少なくとも一方を含む多孔体である
請求項5または6に記載の電気化学デバイス。
The electrochemical device according to claim 5 or 6, wherein the heat-shrinkable film is a porous body containing at least one of polyethylene and polypropylene.
JP2008049076A 2008-02-29 2008-02-29 Manufacturing method of electrochemical device, and electrochemical device Pending JP2009206006A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101415575B1 (en) * 2011-10-18 2014-07-07 에스케이이노베이션 주식회사 Wrapping Method of Jelly roll for Battery Cell of Secondary Battery

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101415575B1 (en) * 2011-10-18 2014-07-07 에스케이이노베이션 주식회사 Wrapping Method of Jelly roll for Battery Cell of Secondary Battery

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