KR101150253B1 - Secondary battery having improved prevention property against humidity permeability - Google Patents

Secondary battery having improved prevention property against humidity permeability Download PDF

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KR101150253B1
KR101150253B1 KR1020070096192A KR20070096192A KR101150253B1 KR 101150253 B1 KR101150253 B1 KR 101150253B1 KR 1020070096192 A KR1020070096192 A KR 1020070096192A KR 20070096192 A KR20070096192 A KR 20070096192A KR 101150253 B1 KR101150253 B1 KR 101150253B1
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battery
secondary battery
ptfe
layer
coating layer
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KR20090030715A (en
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이연우
김민수
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주식회사 엘지화학
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings, jackets or wrappings of a single cell or a single battery
    • H01M50/116—Primary casings, jackets or wrappings of a single cell or a single battery characterised by the material
    • H01M50/124—Primary casings, jackets or wrappings of a single cell or a single battery characterised by the material having a layered structure
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings, jackets or wrappings of a single cell or a single battery
    • H01M50/102—Primary casings, jackets or wrappings of a single cell or a single battery characterised by their shape or physical structure
    • H01M50/105—Pouches or flexible bags
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings, jackets or wrappings of a single cell or a single battery
    • H01M50/116—Primary casings, jackets or wrappings of a single cell or a single battery characterised by the material
    • H01M50/117—Inorganic material
    • H01M50/119—Metals
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings, jackets or wrappings of a single cell or a single battery
    • H01M50/116—Primary casings, jackets or wrappings of a single cell or a single battery characterised by the material
    • H01M50/121—Organic material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings, jackets or wrappings of a single cell or a single battery
    • H01M50/116—Primary casings, jackets or wrappings of a single cell or a single battery characterised by the material
    • H01M50/124—Primary casings, jackets or wrappings of a single cell or a single battery characterised by the material having a layered structure
    • H01M50/1245—Primary casings, jackets or wrappings of a single cell or a single battery characterised by the material having a layered structure characterised by the external coating on the casing
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings, jackets or wrappings of a single cell or a single battery
    • H01M50/131—Primary casings, jackets or wrappings of a single cell or a single battery characterised by physical properties, e.g. gas-permeability or size
    • H01M50/133—Thickness
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings, jackets or wrappings of a single cell or a single battery
    • H01M50/14—Primary casings, jackets or wrappings of a single cell or a single battery for protecting against damage caused by external factors
    • H01M50/141—Primary casings, jackets or wrappings of a single cell or a single battery for protecting against damage caused by external factors for protecting against humidity
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/20—Mountings; Secondary casings or frames; Racks, modules or packs; Suspension devices; Shock absorbers; Transport or carrying devices; Holders
    • H01M50/204—Racks, modules or packs for multiple batteries or multiple cells
    • H01M50/207—Racks, modules or packs for multiple batteries or multiple cells characterised by their shape
    • H01M50/211—Racks, modules or packs for multiple batteries or multiple cells characterised by their shape adapted for pouch cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/20—Mountings; Secondary casings or frames; Racks, modules or packs; Suspension devices; Shock absorbers; Transport or carrying devices; Holders
    • H01M50/249—Mountings; Secondary casings or frames; Racks, modules or packs; Suspension devices; Shock absorbers; Transport or carrying devices; Holders specially adapted for aircraft or vehicles, e.g. cars or trains
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/543—Terminals
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2220/00—Batteries for particular applications
    • H01M2220/20—Batteries in motive systems, e.g. vehicle, ship, plane
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2300/00—Electrolytes
    • H01M2300/0017—Non-aqueous electrolytes
    • H01M2300/0065—Solid electrolytes
    • H01M2300/0082—Organic polymers
    • 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

Abstract

본 발명은, 금속층과 수지층을 포함하는 라미네이트 시트의 전지케이스 내부에 전극조립체를 삽입하고 열융착시킨 구조의 이차전지로서, 전극단자를 제외하고 상기 열융착으로 형성된 전지케이스 외주면의 실링부위를 포함한 전지셀의 외면 전체에 연속된 PTFE(polytetrafluoroethylene) 층이 코팅되어 있는 이차전지를 제공한다.The present invention is a secondary battery having a structure in which an electrode assembly is inserted into a battery case of a laminate sheet including a metal layer and a resin layer and heat-sealed, and includes a sealing portion on the outer circumferential surface of the battery case formed by the heat-fusion except for an electrode terminal. Provided is a secondary battery having a continuous polytetrafluoroethylene (PTFE) layer coated on the entire outer surface of a battery cell.

본 발명에 따른 이차전지는 간단한 공정을 통해 PTFE 코팅층을 전지의 전면에 형성할 수 있어서 실링부위 뿐만 아니라 전지케이스 자체를 통한 수분의 침투를 방지할 수 있을 뿐만 아니라, 코팅층이 전체적으로 연속되어 있으므로 내구성 및 밀봉성이 우수하여 결과적으로 전지의 장기간 보존 특성을 향상시키는 효과가 있다.The secondary battery according to the present invention can form a PTFE coating layer on the front surface of the battery through a simple process to prevent the penetration of moisture through the battery case itself as well as the sealing portion, and because the coating layer is continuously continuous, The sealing property is excellent, and as a result, there is an effect of improving the long term storage characteristics of the battery.

Description

향상된 내수분 침투성의 이차전지 {Secondary Battery Having Improved Prevention Property against Humidity Permeability}Secondary Battery Having Improved Prevention Property against Humidity Permeability}

본 발명은 외주면에 PTFE(polytetrafluoroethylene) 층이 코팅되어 있는 이차전지에 관한 것으로, 금속층과 수지층을 포함하는 라미네이트 시트의 전지케이스 내부에 전극조립체를 삽입하고 열융착시킨 구조의 이차전지로서, 전극단자를 제외하고 상기 열융착으로 형성된 전지케이스 외주면의 실링부위를 포함하여 전지셀의 외면 전체에 연속된 PTFE 층이 코팅되어 있는 것으로 구성되어 있어서, 전지 내부로의 수분 침투를 방지하고 코팅면이 전체적으로 연속적으로 되어 있어서 장기간 사용시의 내구성과 밀봉성이 우수한 이차전지에 관한 것이다.The present invention relates to a secondary battery having a PTFE (polytetrafluoroethylene) layer coated on an outer circumferential surface thereof, the secondary battery having a structure in which an electrode assembly is inserted into a battery case of a laminate sheet including a metal layer and a resin layer, and heat-sealed. Except for the sealing portion of the outer peripheral surface of the battery case formed by the heat-sealing is composed of a continuous PTFE layer is coated on the entire outer surface of the battery cell, to prevent moisture penetration into the battery and the coating surface is continuous throughout The present invention relates to a secondary battery that is excellent in durability and sealing property in long-term use.

이차전지는 휴대폰, 노트북, 캠코더 등 모바일 기기들의 전원으로 널리 사용되고 있다. 특히, 리튬 이차전지의 사용은 작동전압이 높고, 단위 중량당 에너지밀도가 높다는 잇점으로 인해 급속도로 증가되고 있는 추세이다.Secondary batteries are widely used as a power source for mobile devices such as mobile phones, laptops and camcorders. In particular, the use of lithium secondary batteries has been rapidly increasing due to the advantages of high operating voltage and high energy density per unit weight.

이러한 리튬 이차전지는 전극과 전해액의 구성에 따라 리튬이온 전지, 리튬 이온 폴리머 전지, 리튬 폴리머 전지 등으로 분류되기도 하며, 그 중 전해액의 누액 가능성이 적으며, 제조가 용이한 리튬이온 폴리머 전지의 사용량이 늘어나고 있다. 리튬이온 폴리머 전지(LiPB)는 전극(양극 및 음극)과 분리막을 열융착시킨 전극조립체에 전해액을 함침시킨 구조로서, 주로 스택형 전극조립체를 알루미늄 라미네이트 시트의 파우치형 케이스에 밀봉한 형태로서 많이 사용되고 있다. 따라서, 리튬이온 폴리머 전지를 종종 파우치형 전지로 칭하기도 한다.The lithium secondary battery may be classified into a lithium ion battery, a lithium ion polymer battery, a lithium polymer battery, and the like according to the composition of the electrode and the electrolyte, and among them, the amount of leakage of the electrolyte is less likely, and the amount of the lithium ion polymer battery that is easy to manufacture is used. This is increasing. Li-ion polymer battery (LiPB) is a structure in which an electrolyte solution is impregnated into an electrode assembly in which electrodes (anode and cathode) and a separator are heat-sealed. have. Thus, lithium ion polymer batteries are often referred to as pouch cells.

도 1 및 2에는 스택형 전극조립체를 포함하고 있는 대표적인 리튬이온 폴리머 전지의 일반적인 구조가 모식적으로 도시되어 있다.1 and 2 schematically show a general structure of a representative lithium ion polymer battery including a stacked electrode assembly.

이들 도면을 참조하면, 리튬이온 폴리머 전지(100)는, 파우치형의 전지케이스(200) 내부에 양극, 음극 및 이들 사이에 배치되는 분리막으로 이루어진 전극조립체(300)가 내장되어 있고, 그것의 양극 및 음극 탭들(301, 302)이 두 개의 전극리드(400, 410)에 용접되어 전지케이스(200)의 외부로 노출되도록 실링(밀봉)되어 있는 구조로 이루어져 있다. Referring to these drawings, the lithium ion polymer battery 100 includes an electrode assembly 300 made of a positive electrode, a negative electrode, and a separator disposed therebetween in a pouch-type battery case 200, and a positive electrode thereof. And the negative electrode tabs 301 and 302 are welded to the two electrode leads 400 and 410 to be sealed to the outside of the battery case 200.

전지케이스(200)는 알루미늄 라미네이트 시트와 같은 연포장재로 되어 있으며, 전극조립체(300)가 안착될 수 있는 오목한 형상의 수납부(230)를 포함하는 케이스 본체(210)와 그러한 본체(210)에 일측이 연결되어 있는 덮개(220)로 이루어져 있다.The battery case 200 is formed of a soft packaging material such as an aluminum laminate sheet, and includes a case body 210 and a body 210 including a recess 230 having a concave shape in which the electrode assembly 300 can be seated. One side is made of a cover 220 is connected.

리튬이온 폴리머 전지(100)에 사용되는 전극조립체(300)는, 도 1에서와 같은 스택형 구조 이외에 젤리롤형 구조 또는 스택/폴딩형 구조도 가능하다. 스택형 전극조립체(300)는 다수의 양극 탭들(301)과 다수의 음극 탭들(302)이 전극리드(400, 410)에 각각 용접되어 있다.The electrode assembly 300 used in the lithium ion polymer battery 100 may have a jelly roll type structure or a stack / fold type structure in addition to the stacked structure as shown in FIG. 1. In the stacked electrode assembly 300, a plurality of positive electrode tabs 301 and a plurality of negative electrode tabs 302 are welded to the electrode leads 400 and 410, respectively.

이러한 폴리머 전지(100)는 수납부(230)에 전극조립체(300)를 안착한 후 덮개(220)를 덮고 본체(210)과의 접촉 부위를 열융착시켜 제조된다. 열융착에 의해 상단 실링부(240)와 측면 실링부(250)가 각각 형성되며, 측면 실링부(250)는 수직으로 상향 절곡하여 전극조립체(300) 쪽으로 밀착시킨다.The polymer battery 100 is manufactured by seating the electrode assembly 300 on the accommodating part 230, covering the lid 220, and heat-sealing the contact portion with the main body 210. The upper sealing part 240 and the side sealing part 250 are formed by thermal fusion, and the side sealing part 250 is bent vertically upward to closely contact the electrode assembly 300.

그러나, 이러한 실링부위는 전지의 다른 부위에 비해 취약한 부위로서, 장기간의 사용시 상기 실링부위를 통해 수분이 침투하여 결과적으로 전지의 수명이 단축되는 원인으로 작용한다.However, these sealing parts are weaker than other parts of the battery, and the water penetrates through the sealing parts when used for a long time, resulting in a shortening of the battery life.

특히, 이러한 폴리머 전지 다수 개를 적층하여 직렬 및/또는 병렬 방식으로 연결하는 중대형 전지모듈의 경우, 장기간의 전지 수명 및 안전성을 요구하고, 일부 전지에서 수분 침투가 발생하게 되면 이로 인해 전지모듈 전체의 성능 저하를 가져오게 되므로 많은 문제점을 일으키게 된다.In particular, in the case of a medium-large battery module in which a plurality of polymer batteries are stacked and connected in series and / or parallel manners, long-term battery life and safety are required. This can cause many problems because of the performance degradation.

따라서, 전지 내부로의 수분 침투를 방지하기 위한 방법으로서, 전극단자가 돌출되어 있는 상단 실링부의 단면 부위에 발수성 물질을 도포하는 기술(일본 특허출원공개 제2005-196979호) 등이 제시된 바 있다. 그러나, 상단 실링부와 그것의 단면 부위에만 발수성 물질을 코팅하는 것은 전지의 구조적 특성상 용이하지 않으며, 일반적으로 내마모성 등의 내구성이 취약한 발수성 물질의 경우, 그것의 코팅층은 전지의 장기간 사용시 부분적인 탈리 현상이 발생하는 문제점을 가지고 있다. Therefore, as a method for preventing the penetration of water into the battery, a technique of applying a water-repellent material to the end surface portion of the upper sealing portion where the electrode terminal protrudes (Japanese Patent Application Laid-Open No. 2005-196979) and the like have been proposed. However, coating the water-repellent material only on the upper sealing portion and its cross-sectional area is not easy due to the structural characteristics of the battery, and in general, in the case of the water-repellent material having poor durability such as wear resistance, its coating layer is partially detached from the battery for a long time. This has a problem that arises.

더욱이, 이후에서 설명하는 바와 같이, 전지케이스를 이루는 알루미늄 라미네이트 시트 역시 장기간 보존시에는 수분 침투가 나타나는 것으로 확인되었으므 로, 상기 방법은 전지케이스 내부로의 수분 침투를 방지하기 위한 근본적인 해결책이 되지 못한다.Furthermore, as will be described later, the aluminum laminate sheet constituting the battery case has also been found to be water infiltration during long-term storage, the method is not a fundamental solution to prevent the water infiltration into the battery case. .

따라서, 선행기술의 문제점을 해소하면서 전지 내부로의 수분 침투를 효과적으로 방지할 수 있는 기술에 대한 필요성이 높은 실정이다.Therefore, there is a high need for a technology that can effectively prevent the penetration of moisture into the battery while solving the problems of the prior art.

본 발명은 상기와 같은 종래기술의 문제점과 과거로부터 요청되어온 기술적 과제를 해결하는 것을 목적으로 한다.SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-described problems of the prior art and the technical problems required from the past.

본 출원의 발명자들은 심도 있는 연구와 다양한 실험을 거듭한 끝에, 전극단자를 제외하고 전지케이스 외주면의 실링부를 포함하여 전지셀의 외면 전체에 PTFE 코팅층을 형성함으로써, 실링부위뿐만 아니라 전지케이스 자체를 통한 수분 침투를 효과적으로 방지할 수 있고, PTFE의 취약한 내구성에도 불구하고 코팅층이 전체적으로 연속되어 있어서 코팅층의 부분적인 탈리를 방지할 수 있으며, 간단한 공정에 의해 코팅층을 형성할 수 있음을 확인하고 본 발명을 완성하기에 이르렀다.After repeated studies and various experiments, the inventors of the present application form a PTFE coating layer on the entire outer surface of the battery cell, including the sealing portion of the outer circumferential surface of the battery case except for the electrode terminal, thereby forming not only the sealing portion but also the battery case itself. It can effectively prevent the penetration of moisture, despite the poor durability of PTFE, the coating layer is continuously continuous to prevent partial detachment of the coating layer, confirming that the coating layer can be formed by a simple process and completed the present invention It came to the following.

따라서, 본 발명에 따른 이차전지는 금속층과 수지층을 포함하는 라미네이트 시트의 전지케이스 내부에 전극조립체를 삽입하고 열융착시킨 구조의 이차전지로서, 전극단자를 제외하고 상기 열융착으로 형성된 전지케이스 외주면의 실링부위를 포함하여 전지셀의 외면 전체에 연속된 PTFE 층이 코팅되어 있는 것으로 구성되어 있다.Accordingly, the secondary battery according to the present invention is a secondary battery having a structure in which an electrode assembly is inserted into a battery case of a laminate sheet including a metal layer and a resin layer and thermally fused, and the battery case outer peripheral surface formed by the heat fusion except for an electrode terminal. Consisting of a continuous PTFE layer is coated on the entire outer surface of the battery cell, including the sealing portion of.

본 발명의 중요한 특징들로는, 수분 침투성을 방지하기 위해 PTFE 코팅층을 형성한다는 점, 전극단자를 제외한 전지셀의 외면 전체에 코팅층을 형성한다는 점, 및 그러한 코팅층이 연속되어 있다는 점 등을 들 수 있다.Important features of the present invention include forming a PTFE coating layer to prevent moisture permeability, forming a coating layer on the entire outer surface of the battery cell except for the electrode terminals, and such a coating layer is continuous.

상기 첫 번째 특징과 관련하여, PTFE 코팅층은 PTFE의 우수한 내발수성으로 인해, 일단 해당 부위에 안정적인 코팅층을 형성하였을 경우에는 수분 침투를 현저하게 방지할 수 있으며, 매우 낮은 계면 장력으로 인해 기타 물질들이 흡착되어 전지의 고장을 유발하는 것을 억제할 수 있다. In relation to the first feature, the PTFE coating layer is due to the excellent water-repellent resistance of PTFE, once the stable coating layer is formed in the site can significantly prevent moisture penetration, and due to the very low interfacial tension other materials are adsorbed This can suppress the occurrence of battery failure.

상기 두 번째 특징과 관련하여, 전지셀 외면 전체에 대한 코팅층의 형성은 작업 공정을 매우 단순화시킬 수 있고, 열융착에 의한 실링부위 뿐만 아니라 전지케이스 자체를 통한 수분의 침투 가능성을 방지할 수 있다. 우선, 코팅 작업의 단순화는 이후 설명하는 바와 같이 코팅용액 내로의 침지, 코팅용액의 분사 등 전지 전체에 대해 일괄적으로 한번에 코팅 작업을 수행함으로써 달성될 수 있다. 또한, 본 발명자들이 행한 실험에 따르면, 라미네이트 시트의 전지케이스 내부에 전극조립체를 삽입하고 열융착시킨 이차전지에서, 전지 내부로의 수분 침투는 열융착에 의해 밀봉한 전지케이스의 실링부에서 주로 발생되지만, 장기간 보존시에는 전지케이스 자체에서도 수분 침투가 발생함이 확인되었다. 구체적으로, 최외층으로서 25 ㎛ 두께의 Polyamide(O-Ny)층, 차단층으로서 40 ㎛ 두께의 알루미늄 층, 및 실란트 층으로서 80 ㎛ 두께의 CPP층으로 이루어진 알루미늄 라미네이트 시트는, 40℃, 90% RH 조건에서의 수분침투율이 3g/m2*24hr/0.1mm 인 것으로 확인되었다.In connection with the second feature, the formation of the coating layer on the entire outer surface of the battery cell can greatly simplify the work process, and can prevent the penetration of moisture through the battery case itself as well as the sealing site by thermal fusion. First, the simplification of the coating operation can be achieved by carrying out the coating operation in one batch on the entire battery, such as immersion into the coating solution, spraying the coating solution, as described later. In addition, according to an experiment conducted by the present inventors, in a secondary battery in which an electrode assembly is inserted into a battery case of a laminate sheet and heat-sealed, moisture penetration into the battery mainly occurs in a sealing portion of a battery case sealed by heat fusion. However, it was confirmed that moisture permeation occurs even in the battery case itself when stored for a long time. Specifically, the aluminum laminate sheet composed of a polyamide (O-Ny) layer having a thickness of 25 μm as the outermost layer, an aluminum layer having a thickness of 40 μm as the barrier layer, and a CPP layer having a thickness of 80 μm as the sealant layer was 40 ° C., 90%. It was found that the moisture permeation rate under RH conditions was 3 g / m 2 * 24hr / 0.1mm.

따라서, 본 발명에 따른 이차전지는 전지케이스의 실링부위 뿐만 아니라 전극단자를 제외한, 전지케이스 외면 전체에 PTFE 층을 코팅하여 전지 내부로의 수분 침투를 근본적으로 방지하여 전지의 보존 특성을 향상시킬 수 있다.Therefore, the secondary battery according to the present invention can improve the storage characteristics of the battery by fundamentally preventing the penetration of moisture into the battery by coating a PTFE layer on the entire outer surface of the battery case, excluding the electrode terminal as well as the sealing portion of the battery case. have.

상기 세 번째 특징과 관련하여, 연속적으로 형성된 코팅층은 그것을 이루는 PTFE의 낮은 내구성(내스크래치성)을 보상하여 전지의 장기간 사용 과정에서 발생하는 부분적인 탈리 현상을 억제할 수 있다. PTFE는 상기와 같은 우수한 내발수성 및 낮은 계면장력의 장점과 함께 내마모성과 기재(base material)에 대한 결합력이 낮다는 단점을 가지고 있다. 따라서, PTFE 코팅층의 단부, 즉, 비코팅 부위와의 계면 단부는 외력의 인가 및/또는 반복적인 충방전시의 부피 변화로 인해 기재로부터 쉽게 탈리되는 경향이 있다. 이러한 코팅층의 탈리는 수분의 침투 경로로 사용될 수 있으므로 PTFE 코팅층의 형성에 따른 효과를 기대하기 어렵다. 반면에, 본 발명에서는 PTFE 코팅층이 전극단자를 제외하고 전지케이스 전면에 연속적으로 형성되어 있으므로, 비코팅 부위에 대한 계면 단부의 크기를 최소화하여 상기와 같은 탈리 현상을 크게 억제할 수 있다.In connection with the third feature, the continuously formed coating layer can compensate for the low durability (scratch resistance) of the PTFE constituting it, thereby suppressing partial detachment phenomenon occurring during long-term use of the battery. PTFE has the disadvantages of low abrasion resistance and low binding strength to the base material, together with the above advantages of excellent water repellency and low interfacial tension. Therefore, the end of the PTFE coating layer, i.e., the interface end with the uncoated portion, tends to be easily detached from the substrate due to the application of external force and / or volume change during repeated charge and discharge. Desorption of such a coating layer can be used as a water penetration path, it is difficult to expect the effect of the formation of the PTFE coating layer. On the other hand, in the present invention, since the PTFE coating layer is continuously formed on the entire surface of the battery case except for the electrode terminal, the detachment phenomenon can be greatly suppressed by minimizing the size of the interface end portion to the uncoated portion.

본 발명에서의 전면 코팅은, 바람직하게는, 전지케이스에 전극조립체가 내장되어 있는 전지셀을 PTFE를 포함하는 용액(코팅용 용액)에 침지시킨 후 꺼내어 건조하는 이른바 침지법에 의해 수행할 수 있다. In the present invention, the front coating may be preferably performed by a so-called dipping method in which a battery cell in which an electrode assembly is embedded in a battery case is immersed in a solution containing PTFE (coating solution) and then taken out and dried. .

이러한 침지법에 있어서, 전지셀을 코팅용 용액에 침지시킨 후 꺼내어 건조 하는 침지 및 건조 과정은 1 회 또는 2 회 이상 실시할 수 있다. 일반적으로, 상기 횟수가 증가할수록 전지케이스 전면에 대한 PTFE 코팅층의 형성이 보장될 수 있으나, 필요에 따라 달라질 수 있음은 물론이다.In this immersion method, the immersion and drying process to be taken out and dried after immersing the battery cell in the coating solution can be carried out once or twice or more. In general, as the number of times increases, the formation of the PTFE coating layer on the front surface of the battery case may be guaranteed, but may be changed as necessary.

상기 코팅용 용액은, 예를 들어, 아세톤 또는 헥산 용매에 PTFE가 액체상 고체입자(Suspension) 형태로 분산되어 있는 구성으로 이루어져 있다.The coating solution, for example, consists of a composition in which PTFE is dispersed in the form of a liquid solid particles (Suspension) in acetone or hexane solvent.

상기 PTFE 코팅층의 두께는 바람직하게는 5 ㎛ 내지 100 ㎛, 더욱 바람직하게는 10 ㎛ 내지 50 ㎛, 특히 바람직하게는 20 ㎛ 내지 30 ㎛이다. 코팅층의 두께가 너무 얇으면 전지셀과의 결합력과 코팅층의 내구성이 떨어져 장기간의 사용시 부분적인 탈리 현상이 발생할 수 있으며, 반대로 너무 두꺼우면 전지셀의 부피가 증가하고 코팅층을 형성하는 공정 시간이 길어지므로 바람직하지 않다.The thickness of the PTFE coating layer is preferably 5 μm to 100 μm, more preferably 10 μm to 50 μm, particularly preferably 20 μm to 30 μm. If the thickness of the coating layer is too thin, the bonding strength with the battery cell and the durability of the coating layer may be reduced, so that partial detachment may occur when used for a long time. On the contrary, when the coating layer is too thick, the volume of the battery cell increases and the process time for forming the coating layer becomes long. Not desirable

상기 전지케이스는 바람직하게는 전지의 박막화와 변형 등이 용이한 알루미늄 라미네이트 시트의 파우치형 케이스일 수 있다.The battery case may preferably be a pouch-type case of an aluminum laminate sheet that is easy to thin and deform the battery.

상기 침지법에 의한 PTFE 코팅층의 형성 방법을 고려할 때, 이차전지에서 양극 단자와 음극 단자는 전지케이스의 일측에 함께 형성되어 있는 것이 바람직하다. Considering the method of forming the PTFE coating layer by the immersion method, in the secondary battery, the positive electrode terminal and the negative electrode terminal are preferably formed together on one side of the battery case.

본 발명에 따른 이차전지는 상기와 같은 구조를 가진 것이라면 특별히 제한되지 않으며, 앞서 설명한 바와 같은 리튬이온 폴리머 전지에 바람직하게 적용될 수 있다. The secondary battery according to the present invention is not particularly limited as long as it has the above structure, and may be preferably applied to the lithium ion polymer battery as described above.

본 발명에 따른 이차전지는 수분이 전지셀 내부로 침투하는 것을 방지하고 내구성 및 밀봉성이 우수하므로, 장기간에 걸쳐 높은 밀봉성과 안전성을 필요로 하는 고출력 대용량의 전지모듈의 단위 셀로 바람직하게 사용될 수 있다.Since the secondary battery according to the present invention prevents moisture from penetrating into the battery cell and has excellent durability and sealing property, the secondary battery may be preferably used as a unit cell of a high output large capacity battery module requiring high sealing performance and safety over a long period of time. .

따라서, 본 발명은 상기 이차전지를 단위 셀로 사용하여 다수의 전지들을 직렬 및/또는 병렬 방식으로 연결한 구조로 이루어진 고출력 대용량의 중대형 전지모듈을 제공한다. Accordingly, the present invention provides a high output large-capacity battery module having a structure in which a plurality of batteries are connected in series and / or in parallel by using the secondary battery as a unit cell.

이러한 전지모듈을 소망하는 출력 및 용량에 따라 조합하여 고출력 대용량의 중대형 전지팩으로도 제조될 수 있다. These battery modules can be manufactured in combination with a desired output and capacity as a medium to large battery pack of high output capacity.

상기 중대형 전지모듈 또는 전지팩은, 앞서 설명한 바와 같은 이차전지의 우수한 내수분 침투성, 견고성 등을 고려할 때, 가혹한 외부 환경에 노출되기 쉽고 장기간에 걸쳐 신뢰성 있는 작동이 요구되며 안전성이 보장되어야 하는 전기자동차, 하이브리드 전기자동차, 전기오토바이, 전기자전거 등의 전원으로 바람직하게 사용될 수 있다. 특히 바람직하게는 전기자동차 또는 하이브리드 전기자동차의 전원으로 사용될 수 있다. 그러나, 중대형 전지모듈 또는 전지팩의 적용 범위가 이들만으로 한정되는 것은 아니다.The medium-to-large battery module or battery pack is an electric vehicle that is easy to be exposed to harsh external environments, requires reliable operation for a long time, and must be secured in consideration of excellent moisture permeability, robustness, etc. of the secondary battery as described above. It can be preferably used as a power source for hybrid electric vehicles, electric motorcycles, electric bicycles and the like. Especially preferably, it can be used as a power source of an electric vehicle or a hybrid electric vehicle. However, the application range of the medium-large battery module or the battery pack is not limited thereto.

기타 전극조립체를 사용하여 이차전지를 제조하는 방법, 중대형 전지모듈의 구조 및 제조방법 등은 당업계에 공지되어 있으므로, 이에 대한 설명은 본 명세서에서 생략한다.Since a method of manufacturing a secondary battery using another electrode assembly, a structure and a manufacturing method of a medium-large battery module, and the like are known in the art, a description thereof will be omitted herein.

도 3에는 본 발명의 하나의 실시예에 따른 전지셀을 PTFE 용액에 침지하는 과정이 모식적으로 도시되어 있다.3 schematically illustrates a process of immersing a battery cell in a PTFE solution according to one embodiment of the present invention.

도 3을 참조하면, 우선, 전지셀(101)은 도 1 및 2에서와 같은 내부 구조로 이루어져 있고 상단에 전극리드들(400, 410)이 돌출되어 있다. 이러한 전극리드들(400, 410) 만을 집게(500)로 잡아 PTFE 용액(610)이 담겨 있는 욕조(600)에 전극리드들(400, 410)의 하단 일부까지 잠기도록 침지하여 전지셀(101)의 전면에 대한 코팅을 행하게 된다. Referring to FIG. 3, first, the battery cell 101 has an internal structure as shown in FIGS. 1 and 2, and electrode leads 400 and 410 protrude from the top. By holding only the electrode leads 400 and 410 with tongs 500, the battery cell 101 is immersed so as to be immersed to a part of the lower end of the electrode leads 400 and 410 in the bath 600 containing the PTFE solution 610. The coating is performed on the entire surface of the.

이러한 침지 작업에 의해 전면에 PTFE 용액(610)이 도포된 전지셀(101)을 욕조(600)로부터 꺼내어 20 ~ 30℃의 온도에서 건조시켜 연속적인 코팅층을 형성할 수 있다. 이러한 침지 및 건조 과정은 1 회 이상 반복적으로 수행되어 다층의 구조로서 PTFE 코팅층을 형성할 수도 있다. By the immersion operation, the battery cell 101 coated with the PTFE solution 610 on the front surface may be taken out of the bath 600 and dried at a temperature of 20 to 30 ° C. to form a continuous coating layer. This dipping and drying process may be performed repeatedly one or more times to form a PTFE coating layer as a multilayer structure.

이상의 설명과 같이, 본 발명에 따른 이차전지는 간단한 공정을 통해 PTFE 코팅층을 전지의 전면에 형성할 수 있어서 실링부위 뿐만 아니라 전지케이스 자체를 통한 수분의 침투를 방지할 뿐만 아니라, 코팅층이 전체적으로 연속되어 있어서 내구성 및 밀봉성이 우수하여 결과적으로 전지의 장기간 보존 특성을 향상시키는 효과가 있다.As described above, the secondary battery according to the present invention can form a PTFE coating layer on the front surface of the battery through a simple process to prevent the penetration of moisture through not only the sealing portion but also the battery case itself, the coating layer is continuously continuous It is excellent in durability and sealing property, resulting in the effect of improving the long-term storage characteristics of the battery.

본 발명이 속한 분야에서 통상의 지식을 가진 자라면 상기 내용을 바탕으로 본 발명의 범주내에서 다양한 응용 및 변형을 행하는 것이 가능할 것이다.Those skilled in the art to which the present invention pertains will be able to perform various applications and modifications within the scope of the present invention based on the above contents.

도 1 및 2는 파우치형 전지케이스를 사용한 종래의 리튬이온 폴리머 전지에서 전지케이스와 전극조립체의 조립과정을 나타낸 사시도와 조립된 상태에서의 평면 투시도이다;1 and 2 are a perspective view showing the assembly process of the battery case and the electrode assembly in a conventional lithium-ion polymer battery using a pouch-type battery case and a plan view in the assembled state;

도 3은 본 발명의 하나의 실시예에 따른 전지셀의 코팅층 형성과정에 대한 모식도이다.3 is a schematic diagram of a coating layer forming process of a battery cell according to an embodiment of the present invention.

<도면의 주요 부호에 대한 설명> DESCRIPTION OF THE RELATED ART [0002]

100, 101: 리튬이온 폴리머 전지 200: 파우치형 전지케이스100 and 101: lithium ion polymer battery 200: pouch type battery case

300: 전극조립체 400, 410: 전극단자300: electrode assembly 400, 410: electrode terminal

500: 집게 610: PTFE 용액500: clamp 610: PTFE solution

Claims (9)

금속층과 수지층을 포함하는 라미네이트 시트의 전지케이스 내부에 전극조립체를 삽입하고 열융착시킨 구조의 이차전지로서, 전극단자를 제외하고 상기 열융착으로 형성된 전지케이스 외주면의 실링부위를 포함하여 전지셀의 외면 전체에 연속된 PTFE 층이 코팅되어 있는 것을 특징으로 하는 이차전지.A secondary battery having a structure in which an electrode assembly is inserted into a battery case of a laminate sheet including a metal layer and a resin layer, and heat-sealed, including a sealing portion of an outer circumferential surface of the battery case formed by the heat-fusion except for an electrode terminal. A secondary battery characterized in that a continuous PTFE layer is coated on the entire outer surface. 제 1 항에 있어서, 상기 PTFE 코팅층은 전지케이스에 전극조립체가 내장되어 있는 전지셀을 PTFE를 포함하는 용액(코팅용 용액)에 침지시킨 후 꺼내어 건조함으로써 제조되는 것을 특징으로 하는 이차전지.The secondary battery of claim 1, wherein the PTFE coating layer is manufactured by immersing a battery cell in which an electrode assembly is embedded in a battery case in a solution containing PTFE (coating solution), and then removing and drying the battery cell. 제 2 항에 있어서, 상기 코팅용 용액은 아세톤 또는 헥산 용매에 PTFE가 액체상 고체입자(Suspension) 형태로 분산되어 있는 것을 특징으로 하는 이차전지.The secondary battery according to claim 2, wherein the coating solution has PTFE dispersed in acetone or hexane solvent in the form of a liquid solid particle. 제 1 항에 있어서, 상기 PTFE 코팅층은 5 ㎛ ~ 100 ㎛의 두께로 형성되어 있는 것을 특징으로 하는 이차전지.The secondary battery of claim 1, wherein the PTFE coating layer has a thickness of about 5 μm to about 100 μm. 제 1 항에 있어서, 상기 전지케이스는 알루미늄 라미네이트 시트의 파우치형 케이스인 것을 특징으로 하는 이차전지.The secondary battery of claim 1, wherein the battery case is a pouch type case of an aluminum laminate sheet. 제 2 항에 있어서, 상기 침지 및 건조 과정은 1 회 또는 2 회 이상 실시하는 것을 특징으로 하는 이차전지.The secondary battery of claim 2, wherein the dipping and drying processes are performed one or two times. 제 1 항에 있어서, 양극 단자와 음극 단자는 전지케이스의 일측에 함께 형성되어 있는 것을 특징으로 하는 이차전지. The secondary battery of claim 1, wherein the positive electrode terminal and the negative electrode terminal are formed together at one side of the battery case. 제 1 항 내지 제 7 항 중 어느 하나에 따른 이차전지를 단위 셀로 사용하는 고출력 대용량의 중대형 전지모듈.A high output large-capacity battery module using the secondary battery according to any one of claims 1 to 7 as a unit cell. 제 8 항에 따른 전지모듈을 출력 및 용량에 따라 조합하여 제조되는 전지팩으로서, 상기 전지팩은 전기자동차 또는 하이브리드 전기자동차의 전원으로 사용되는 것을 특징으로 하는 중대형 전지팩.A battery pack manufactured by combining the battery module according to claim 8 according to output and capacity, wherein the battery pack is a medium-large battery pack, characterized in that used as a power source for an electric vehicle or a hybrid electric vehicle.
KR1020070096192A 2007-09-21 2007-09-21 Secondary battery having improved prevention property against humidity permeability KR101150253B1 (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH1140114A (en) 1997-07-23 1999-02-12 Sumitomo Electric Ind Ltd Nonaqueous electrolyte battery
JP2000277062A (en) 1999-03-29 2000-10-06 Sanyo Electric Co Ltd Thin battery
KR20080003473A (en) * 2006-07-03 2008-01-08 주식회사 엘지화학 Secondary battery having improved sealing property at heat-melted portion of case

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH1140114A (en) 1997-07-23 1999-02-12 Sumitomo Electric Ind Ltd Nonaqueous electrolyte battery
JP2000277062A (en) 1999-03-29 2000-10-06 Sanyo Electric Co Ltd Thin battery
KR20080003473A (en) * 2006-07-03 2008-01-08 주식회사 엘지화학 Secondary battery having improved sealing property at heat-melted portion of case

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