WO2024128872A1 - Secondary battery - Google Patents

Secondary battery Download PDF

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Publication number
WO2024128872A1
WO2024128872A1 PCT/KR2023/020793 KR2023020793W WO2024128872A1 WO 2024128872 A1 WO2024128872 A1 WO 2024128872A1 KR 2023020793 W KR2023020793 W KR 2023020793W WO 2024128872 A1 WO2024128872 A1 WO 2024128872A1
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WO
WIPO (PCT)
Prior art keywords
sealing
line
distance
folding
outer end
Prior art date
Application number
PCT/KR2023/020793
Other languages
French (fr)
Korean (ko)
Inventor
황순철
이성원
백상민
이영미
홍의진
Original Assignee
주식회사 엘지에너지솔루션
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by 주식회사 엘지에너지솔루션 filed Critical 주식회사 엘지에너지솔루션
Priority claimed from KR1020230182678A external-priority patent/KR20240095053A/en
Publication of WO2024128872A1 publication Critical patent/WO2024128872A1/en

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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
    • H01M50/102—Primary casings; Jackets or wrappings 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
    • H01M50/131—Primary casings; Jackets or wrappings characterised by physical properties, e.g. gas permeability, size or heat resistance
    • 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
    • H01M50/183—Sealing members
    • H01M50/186—Sealing members characterised by the disposition of the sealing members
    • 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

Definitions

  • the present invention relates to secondary batteries.
  • secondary batteries refer to batteries that can be charged and discharged, unlike primary batteries that cannot be recharged, and are widely used in electronic devices such as mobile phones, laptops, camcorders, and electric vehicles.
  • lithium secondary batteries have a larger capacity than nickel-cadmium batteries or nickel-hydrogen batteries, and their use is rapidly increasing because of their high energy density.
  • secondary batteries can be classified into cylindrical or square batteries in which the electrode assembly is embedded in a cylindrical or square metal can, and pouch-type batteries in which the electrode assembly is embedded in a pouch-type case of a laminate sheet. there is.
  • a pouch-type secondary battery (1, pouch-type cell) includes an electrode assembly 2 formed by alternately stacking electrodes and separators, and a pouch-type exterior material 20 in which the electrode assembly 2 is accommodated. Electrode tabs 15 may be connected to the electrodes of the electrode assembly 2, respectively. The electrode tabs 15 may be welded to each other in a predetermined area and then connected to the electrode lead 17 by welding.
  • the exterior material 20 includes a receiving portion 21 to accommodate the electrode assembly 2.
  • the receiving portion 21 of the exterior material 20 may be formed of one or two recessed portions.
  • Figure 1 illustrates a receiving portion 21 formed from two indented portions.
  • a sealing portion 23 (sealing portion or terrace) is formed around the circumference of the receiving portion 21 by sealing.
  • the sealing portion 23 of the secondary battery may be folded toward the receiving portion 21. This folding may be applied once or more than twice.
  • the object of the present invention is to provide a secondary battery having a folding structure in which the insulation resistance does not decrease even if the sealing portion is folded multiple times, or the decrease in the insulation resistance is minimized.
  • the secondary battery includes an electrode assembly, a pouch-type exterior material having a receiving portion for accommodating the electrode assembly, and a sealing portion formed to surround at least a portion of the accommodating portion to seal the accommodating portion, wherein the sealing portion is a portion of the sealing portion.
  • a first folding portion provided by folding the outer end of the sealing portion toward the receiving portion along a first folding line spaced apart from the outer end by a first distance toward the receiving portion, and a second folding portion provided from the first folding line toward the receiving portion.
  • the first folding portion includes a second folding portion provided by folding the first folding portion toward the receiving portion along a second folding line spaced apart by a distance, and the sealing portion is spaced a predetermined distance from an outer end of the sealing portion toward the receiving portion.
  • a sealing line When a predetermined line is referred to as a sealing line, it includes a sealing portion formed by fusion sealing from the outer end of the sealing portion to the sealing line, and the distance from the outer end of the sealing portion to the receiving portion is referred to as the width of the sealing portion. When doing so, the distance from the sealing line to the receiving part may be 45% to 55% of the width of the sealing part.
  • the distance from the outer end of the sealing part to the first folding line may be 60% to 80% of the distance from the outer end of the sealing part to the sealing line.
  • the distance from the receiving part to the second folding line may be 18% to 34% of the distance from the sealing line to the receiving part.
  • the sealing line may be located between the first folding line and the second folding line.
  • a secondary battery in another example, includes an electrode assembly, a pouch-type exterior material having an accommodating portion for accommodating the electrode assembly, and a sealing portion formed to surround at least a portion of the accommodating portion to seal the accommodating portion, and the sealing portion A first folding portion in which the outer end of the sealing portion is folded toward the receiving portion along a first folding line that is spaced apart from the outer end of the sealing portion toward the receiving portion by a first distance and is provided in parallel with the outer end of the sealing portion, and a second folding portion in which the first folding portion is folded toward the receiving portion along a second folding line that is spaced apart from the first folding line toward the receiving portion by a second distance and is parallel to the first folding line.
  • the width of the sealing portion it includes, and when the distance from the outer end of the sealing portion to the receiving portion is referred to as the width of the sealing portion, the first distance is 34.65% to 42.35% of the width of the sealing portion, and the second distance is 34.65% to 42.35% of the width of the sealing portion. It may be 43.65% to 53.35%.
  • a sealing line when a predetermined line spaced a predetermined distance from the outer end of the sealing part toward the receiving part and provided parallel to the outer end of the sealing part is referred to as a sealing line, the sealing part is located at the outer end of the sealing part.
  • the sealing line is sealed by fusion, the sealing line is located between the first folding line and the second folding line, and the distance from the second folding line to the sealing line is 20% or more of the width of the sealing portion.
  • a sealing line when a predetermined line spaced a predetermined distance from the outer end of the sealing part toward the receiving part and provided parallel to the outer end of the sealing part is referred to as a sealing line, the sealing part is located at the outer end of the sealing part.
  • the sealing line is sealed by fusion, the sealing line is located between the first folding line and the second folding line, and the distance from the second folding line to the sealing line is from the outer end of the sealing portion to the sealing line. It may be more than 40% of the distance to the line.
  • a sealing line when a predetermined line spaced a predetermined distance from the outer end of the sealing part toward the receiving part and provided parallel to the outer end of the sealing part is referred to as a sealing line, the sealing part is located at the outer end of the sealing part.
  • the sealing line is sealed by fusion, but the sealing line to the receiving portion is not fused, the sealing line is located between the first folding line and the second folding line, and the sealing line is connected to the receiving portion.
  • the distance to may be 40% or more of the width of the sealing portion.
  • a secondary battery in another example, includes an electrode assembly, a pouch-type exterior material having an accommodating portion for accommodating the electrode assembly, and a sealing portion formed to surround at least a portion of the accommodating portion to seal the accommodating portion, and the sealing portion A first folding portion in which the outer end of the sealing portion is folded toward the receiving portion along a first folding line that is spaced apart from the outer end of the sealing portion toward the receiving portion by a first distance and is provided in parallel with the outer end of the sealing portion, and a second folding portion in which the first folding portion is folded toward the receiving portion along a second folding line that is spaced apart from the first folding line toward the receiving portion by a second distance and is parallel to the first folding line.
  • the sealing part is spaced a predetermined distance from the outer end of the sealing part toward the receiving part, and when a predetermined line provided parallel to the outer end of the sealing part is referred to as a sealing line, the sealing part is separated from the outer end of the sealing part by a predetermined distance.
  • the sealing line is sealed by fusion, and the distance from the second folding line to the sealing line may be 40% or more of the distance from the outer end of the sealing portion to the sealing line.
  • the sealing line may be located between the first folding line and the second folding line.
  • a decrease in insulation resistance does not occur or the decrease in insulation resistance can be minimized even if the sealing portion is folded multiple times.
  • the defective rate of insulation resistance can be improved by sufficiently securing the portion of the seal that is not fused (die-seal gap).
  • FIG. 1 is a diagram showing an example of a pouch-type secondary battery.
  • Figure 2 is a perspective view showing a secondary battery according to an embodiment of the present invention.
  • FIGS 3 to 6 are diagrams sequentially showing the process of manufacturing the secondary battery of Figure 2.
  • FIG. 2 is a perspective view showing a secondary battery according to an embodiment of the present invention
  • Figures 3 to 6 are diagrams sequentially showing the process of manufacturing the secondary battery of Figure 2.
  • the secondary battery according to this embodiment may include an electrode assembly 110 and an exterior material 120, as shown in FIG. 3 .
  • FIG. 3 is a perspective view illustrating the secondary battery of FIG. 2 before the sealing portions 140 (141, 142) are folded.
  • the electrode assembly 110 may be formed by alternately stacking electrodes and separators. Electrodes may include an anode and a cathode.
  • the electrode assembly 110 may include an electrode tab (see FIG. 1) connected to the electrode. The electrode tab may be provided separately, or may be provided as part of the current collector constituting the electrode.
  • the exterior material 120 may be a pouch-type exterior material 120 that is formed by molding a laminate sheet and accommodates the electrode assembly 110.
  • the pouch-type exterior material 120 may include a receiving portion 130.
  • the pouch-type exterior material 120 may be prepared by sealing two exterior materials arranged to face each other while being accommodated in the electrode assembly 110 . In this case, the edges of the two exterior materials can be completely sealed. The sealing portion 140 can be formed through this sealing.
  • the pouch-type exterior material may be formed by folding one exterior material (see Figure 1). In this case, the remaining edge of one exterior material, excluding the folded portion, may be sealed. 3 and other examples illustrate the exterior material 120 forming the receiving portion 130 with one indented portion.
  • the pouch-type exterior material 120 may be manufactured from a laminate sheet including a metal layer such as aluminum, a first resin layer disposed on the inner surface of the metal layer, and a second resin layer disposed on the outer surface of the metal layer.
  • the first resin layer may be a layer formed of polypropylene (PP). High insulation and corrosion resistance are required for the first resin layer, and the first resin layer may be formed of another resin that satisfies these requirements.
  • the second resin layer may be a layer formed of polyethylene terephthalate (PET). The second resin layer needs to protect the secondary battery and electrically insulate the secondary battery, and the second resin layer may be formed of another resin that satisfies these requirements.
  • the sealing portion 140 has a first folding line (F 1 ) spaced apart from the outer end 140a of the sealing portion 140 toward the receiving portion 130 by a first distance (L 1 ). ), the outer end 140a of the sealing portion 140 may include a first folding portion 141 (see FIGS. 2 and 5) that is provided by being folded toward the receiving portion 130.
  • the first folding line (F 1 ) may be provided parallel to the outer end (140a) of the sealing portion (140).
  • FIG. 4 is a cross-sectional view taken along line AA of the secondary battery of FIG. 3.
  • FIG. 5 is a cross-sectional view showing a secondary battery of FIG. 4 in which the outer end of the sealing portion is folded along a first folding line to form a first folded portion. 4 and 5, the electrode assembly is not shown for convenience of illustration.
  • the sealing portion 140 has a first folding portion 141 along a second folding line (F 2 ) spaced apart from the first folding line (F 1 ) by a second distance (L 2 ) toward the receiving portion 130. It may include a second folding portion 142 (see FIGS. 2 and 6) that is folded toward the receiving portion 130.
  • the second folding line (F 2 ) may be provided parallel to the first folding line (F 1 ).
  • FIG. 6 is a cross-sectional view showing a secondary battery of FIG. 5 in which the first folded portion of the sealing portion is folded along a second folding line to form a second folded portion. In Figure 6, the electrode assembly is not shown for convenience of illustration.
  • the sealing portion 140 may include a sealing portion 151 formed by fusion sealing from the outer end 140a of the sealing portion 140 to the sealing line S.
  • the sealing line (S) may be provided parallel to the outer end (140a) of the sealing portion (140).
  • the sealing line (S) may be located between the first folding line (F 1 ) and the second folding line (F 2 ).
  • the fusion may be heat fusion.
  • the distance from the sealing line S to the receiving part 130 may be 45% to 55% of the width (L W ) of the sealing portion 140 .
  • the distance (L 3 ) from the outer end (140a) of the sealing portion (140) to the sealing line (S) may be 45% to 55% of the width (L W ) of the sealing portion (140).
  • the upper distance (L 4 ) is 45% of the width (L W ) of the seal 140
  • the upper distance (L 3 ) may be 55% of the width (L W ) of the seal 140.
  • the sum of the upper distance (L 4 ) and the upper distance (L 3 ) may be equal to the width (L W ) of the sealing portion 140.
  • the width (L W ) of the sealing portion 140 may be 10 mm, and the distance (L 3 ) from the outer end (140a) of the sealing portion 140 to the sealing line (S) may be 10 mm. ) may be 5 mm, which is 50% of the width (L W ).
  • the width (L W ) of the sealing portion 140 may be 10 mm, and the distance (L 4 ) from the sealing line (S) to the receiving portion 130 may be 50 mm of the width (L W ) of the sealing portion 140. % can be 5mm.
  • the sealing portion 140 may include the sealing portion 151 described above and an unsealed portion (sealing line of the sealing portion ⁇ boundary between the sealing portion and the receiving portion; 152, 153) to be described later. Some 152 of the unsealed portions 152 and 153 are not designed to be fused, but may be temporarily fused due to heat introduced during the sealing of the sealed portion 151. If the distance L 4 from the sealing line S to the receiving part 130 is less than 45% of the width L W of the sealing part 140, the temporary attachment area 152 and the second folding line are attached as above. Since it is difficult to secure a sufficient separation distance between (F 2 ), there is a risk that the folding knife for pressing the second folding line (F 2 ) will also pressurize the attachment area 152.
  • the unsealed portion 153 of the sealing portion 140 may be opened due to the gas generated inside the receiving portion 130 to serve as a space for accommodating the gas, and the above distance L 4 is the sealing portion 153. If it is less than 45% of the width (L W ) of (140), a sufficient space to accommodate gas may not be formed when gas is generated. This may result in deterioration of the high-temperature storage durability of the secondary battery.
  • the sealing line is formed at the outer end 140a of the sealing part 140. Since the distance L 3 to (S) is relatively short, there is a risk that the width of the sealing portion 151 may not be sufficient. If the width of the sealing portion 151 is not sufficient, the sealing performance of the sealing portion 140 may not be sufficient.
  • the distance from the outer end (140a) of the sealing part 140 to the first folding line (F 1 ), that is, the first distance (L 1 ) is the distance from the outer end (140a) of the sealing part 140 to the sealing line (S) It may be 60% to 80% of the distance to (L 3 ).
  • the distance (L 3 ) from the outer end (140a) of the sealing portion (140) to the sealing line (S) may be 5 mm
  • the first folding line from the outer end (140a) of the sealing portion (140) may be 5 mm.
  • the distance (L 1 ) to (F 1 ) may be 3.85 mm, which is 77% of the above distance (L 3 ).
  • the outer end 140a of the sealing portion 140 is folded along the first folding line F 1 to form the first folding portion 141, where the upper distance L 1 is shown in FIG. If 4) is less than 60% of the above distance (L 3 ; Figure 4), the part of the sealing part 140 that is folded upward from the unfolded part (see the sealing part of the upper layer of the two layers of sealing parts in Figure 5)
  • the length may be shortened. If the length of the folded part is shortened, it may be difficult to maintain the folded shape of the sealing part stably.
  • the above distance (L 1 ) exceeds 80% of the above distance (L 3 ), it is difficult to secure a sufficient separation distance between the attachment area 152 and the first folding line (F 1 ), so that the first folding line (F There is a risk that the folding knife for pressurizing the 1 ) may also pressurize the adhesive area 152 . If the folding knife presses the adhesive area 152 and a crack occurs in the adhesive area 152, a defect in insulation resistance may occur.
  • the distance (L 6 ) from the receiving part 130 to the second folding line (F 2 ) may be 18% to 34% of the distance (L 4 ) from the sealing line (S) to the receiving part 130.
  • the distance (L 4 ) from the sealing line (S) to the receiving part 130 may be 5 mm
  • the distance (L 6 ) from the receiving part 130 to the second folding line (F 2 ) may be 5 mm. It may be 1.3 mm, which is 26% of the above distance (L 4 ).
  • the upper distance (L 6 ) is less than 18% of the upper distance (L 4 ), the separation distance between the second folding line (F 2 ) and the receiving portion 130 becomes too short, so that the second folding line (F 2 ) It may be difficult for the folding knife to press the second folding line F 2 smoothly without interfering with the receiving portion 130 .
  • the upper distance (L 6 ) is greater than 34% of the upper distance (L 4 ), the portion of the sealing portion 140 located adjacent to the receiving portion 130 and not folded (see the left portion of F 2 in FIG. 6) As the length becomes longer, the overall volume occupied by the secondary battery may increase. An increase in total volume may result in a decrease in volumetric energy density.
  • the ratio of the first distance L 1 to the width L W of the seal 140 is 34.65% to 42.35%
  • the ratio of the second distance (L 2 ) to the width (L W ) may be 43.65% to 53.35%.
  • a decrease in insulation resistance may not occur or a decrease in insulation resistance may be minimized even if the sealing portion 140 is folded multiple times.
  • the insulation resistance defect rate was confirmed to be 0.6% at 100 M ⁇ .
  • the first distance L 1 may be 3.85 mm
  • the second distance L 2 may be 4.85 mm
  • the width L W of the sealing portion 140 may be 10 mm.
  • the ratio of the first distance (L 1 ) to the width (L W ) of the sealing portion 140 may be 38.5%
  • the second distance (L 2 ) to the width (L W ) of the sealing portion 140 The ratio may be 48.5%.
  • the ratio of the distance (L 5 ) from the second folding line (F 2 ) to the sealing line (S) to the width (L W ) of the sealing portion 140 may be 20% or more.
  • the distance (L 5 ) from the second folding line (F 2 ) to the sealing line (S) may be 3.7 mm, where the distance (L) relative to the width (L W ) of the sealing portion 140 5 ) the rate may be 37%.
  • the distance (L 5 ) from the second folding line (F 2 ) to the sealing line (S) is 40% or more of the distance (L 3 ) from the outer end (140a) of the sealing portion 140 to the sealing line (S). You can.
  • a portion of the sealing portion (outer end of the sealing portion ⁇ sealing line of the sealing portion 151) may be sealed due to fusion between the first resin layers (eg, PP) of the exterior material.
  • a portion 152 of the remainder of the sealing portion (sealing line of the sealing portion ⁇ boundary between the sealing portion and the receiving portion; 152, 153) may also be temporarily fused due to heat introduced during fusion of the fusion area 151 (sealing portion).
  • Such a temporary adhesion area 152 may be generated in approximately 20% of the fusion area 151 (e.g., a 1 mm adhesive area may be generated for a 5 mm fused area).
  • the distance (L 5 ) from the second folding line (F 2 ) to the sealing line (S) may be 3.7 mm, and the third distance (L 3 ) may be 5 mm, where the above distance (L 5 ) may be 74% of the first distance (L 1 ).
  • the sealing portion 140 When the sealing portion 140 is sealed by fusion from the outer end 140a of the sealing portion 140 to the sealing line S, but is not fused from the sealing line S to the receiving portion 130 (temporarily bonded area) (Unlike the fusion area where fusion is scheduled, it can be seen that it is not an area where fusion was scheduled, so it is regarded as an area that is not fused in this description), and the sealing line ( The ratio of the distance (L 4 ) from S) to the receiving portion 130 may be 40% or more.
  • the secondary battery of this embodiment can improve the defect rate of insulation resistance by sufficiently securing the non-fused portion (die-seal gap; 153) in addition to the fusion area 151 and the adhesive area 152 of the sealing portion 140. there is.
  • the distance (L 4 ) from the sealing line (S) to the receiving part 130 may be 5 mm, where the ratio of the above distance (L 4 ) to the width (L W ) of the sealing part 140 may be 50%.
  • the above distance (L 4 ) is 45% to 55% of the width (L W ) of the sealing portion 140 as described above.
  • a voltage e.g. 25V
  • the metal layer e.g., aluminum layer
  • V/I the exterior material
  • the insulation voltage of the secondary battery can be obtained by measuring the voltage value between the anode and the metal layer (eg, aluminum layer) of the exterior material. For example, in a normal state (a state in which no contact occurs between the electrolyte and the metal layer), the voltage difference will not be measured, and in a defective state (a state in which contact occurs between the electrolyte and the metal layer), the potential difference will not be measured between the anode and the metal layer. will be.
  • a normal state a state in which no contact occurs between the electrolyte and the metal layer
  • a defective state a state in which contact occurs between the electrolyte and the metal layer
  • T in FIG. 4 refers to the thickness of the receiving portion 130, which may be 8.55 mm.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Sealing Battery Cases Or Jackets (AREA)

Abstract

The present invention relates to a secondary battery comprising an electrode assembly, an accommodating portion accommodating the electrode assembly, and a pouch-type exterior material having an encapsulation portion formed to surround at least a portion of the accommodating portion so as to encapsulate the accommodating portion, wherein the encapsulation portion includes a first folding portion formed by folding the outer end of the encapsulation portion toward the accommodating portion along a first folding line spaced apart from the outer end of the encapsulation portion toward the accommodating portion by a first distance and a second folding portion formed by folding the first folding portion toward the accommodating portion along a second folding line spaced apart from the first folding line toward the accommodating portion by a second distance, and when a certain line spaced apart from the outer end of the encapsulation portion toward the accommodating portion by a certain distance is referred to as a sealing line, the encapsulation portion includes a sealing portion formed by fusion-sealing from the outer end of the encapsulation portion to the sealing line, and when a distance from the outer end of the encapsulation portion to the accommodating portion is referred to as the width of the encapsulation portion, a distance from the sealing line to the accommodating portion may be 45% to 55% of the width of the encapsulation portion.

Description

이차 전지secondary battery
관련출원과의 상호인용Cross-citation with related applications
본 출원은 2022년 12월 16일자 한국특허출원 10-2022-0176561 및 2023년 12월 15일자 한국특허출원 10-2023-0182678에 기초한 우선권의 이익을 주장하며, 해당 한국특허출원의 문헌에 개시된 모든 내용은 본 명세서의 일부로서 포함된다.This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0176561, dated December 16, 2022, and Korean Patent Application No. 10-2023-0182678, dated December 15, 2023, and all patents disclosed in the documents of the relevant Korean patent application. The contents are incorporated as part of this specification.
기술분야Technology field
본 발명은 이차 전지에 관한 것이다.The present invention relates to secondary batteries.
일반적으로, 이차 전지는 충전이 불가능한 일차 전지와 달리, 충방전이 가능한 전지를 의미하며, 휴대폰, 노트북, 캠코더 등의 전자기기 또는 전기 자동차 등에 널리 사용되고 있다. 특히, 리튬 이차 전지는 니켈-카드뮴 전지 또는 니켈-수소 전지보다 큰 용량을 가지며, 에너지 밀도가 높기 때문에 그 활용 정도가 급속도로 증가되는 추세에 있다.In general, secondary batteries refer to batteries that can be charged and discharged, unlike primary batteries that cannot be recharged, and are widely used in electronic devices such as mobile phones, laptops, camcorders, and electric vehicles. In particular, lithium secondary batteries have a larger capacity than nickel-cadmium batteries or nickel-hydrogen batteries, and their use is rapidly increasing because of their high energy density.
이차 전지는 전지 케이스의 형상에 따라, 전극 조립체가 원통형 또는 각형의 금속 캔에 내장되어 있는 원통형 또는 각형 전지와, 전극 조립체가 라미네이트 시트의 파우치형 케이스에 내장되어 있는 파우치형 전지 등으로 분류될 수 있다.Depending on the shape of the battery case, secondary batteries can be classified into cylindrical or square batteries in which the electrode assembly is embedded in a cylindrical or square metal can, and pouch-type batteries in which the electrode assembly is embedded in a pouch-type case of a laminate sheet. there is.
도 1은 파우치형 이차 전지의 일례를 도시하는 도면이다. 파우치형 이차 전지(1, 파우치형 셀)는 전극과 분리막이 교대로 적층되어 형성되는 전극 조립체(2)와, 전극 조립체(2)가 내부에 수용되는 파우치형 외장재(20)를 포함한다. 전극 조립체(2)의 전극들에는 전극탭들(15)이 각각 연결될 수 있다. 전극탭들(15)은 소정 영역에서 서로 용접된 후 전극리드(17)에 용접으로 연결될 수 있다. 외장재(20)는 전극 조립체(2)의 수용을 위해 수용부(21)를 포함한다. 외장재(20)의 수용부(21)는 1개 또는 2개의 만입 형상 부분으로 형성될 수 있다. 도 1에는 2개의 만입 형상 부분으로 형성되는 수용부(21)가 예시되어 있다. 수용부(21)의 둘레 주변에는 실링에 의해 실링부(23; 밀봉부 또는 테라스)가 형성된다. 이차 전지가 차지하는 공간을 감소시켜 이차 전지의 부피 에너지 밀도를 향상시키기 위해, 이차 전지의 실링부(23)가 수용부(21) 쪽으로 폴딩될 수도 있다. 이런 폴딩은 1회 또는 2회 이상 적용될 수도 있다.1 is a diagram showing an example of a pouch-type secondary battery. A pouch-type secondary battery (1, pouch-type cell) includes an electrode assembly 2 formed by alternately stacking electrodes and separators, and a pouch-type exterior material 20 in which the electrode assembly 2 is accommodated. Electrode tabs 15 may be connected to the electrodes of the electrode assembly 2, respectively. The electrode tabs 15 may be welded to each other in a predetermined area and then connected to the electrode lead 17 by welding. The exterior material 20 includes a receiving portion 21 to accommodate the electrode assembly 2. The receiving portion 21 of the exterior material 20 may be formed of one or two recessed portions. Figure 1 illustrates a receiving portion 21 formed from two indented portions. A sealing portion 23 (sealing portion or terrace) is formed around the circumference of the receiving portion 21 by sealing. In order to improve the volumetric energy density of the secondary battery by reducing the space occupied by the secondary battery, the sealing portion 23 of the secondary battery may be folded toward the receiving portion 21. This folding may be applied once or more than twice.
한편, 파우치형 이차 전지의 안전성을 향상시켜 파우치형 이차 전지의 품질을 높이기 위해, 최근 파우치형 이차 전지의 절연 저항을 매우 높이는 것(예. 종래 1MΩ에서 100MΩ으로 강화)이 요구되고 있다. 그런데 실링부(23)의 폴딩은 절연 성능의 불량을 발생시켜 절연 저항의 저하를 유발할 수도 있다. 이런 문제는 실링부(23)를 복수 회 폴딩할 때 더 크게 나타날 수 있다.Meanwhile, in order to improve the quality of pouch-type secondary batteries by improving their safety, it has recently been required to greatly increase the insulation resistance of pouch-type secondary batteries (e.g., strengthening from the conventional 1 MΩ to 100 MΩ). However, folding of the sealing portion 23 may cause poor insulation performance and a decrease in insulation resistance. This problem may become more severe when the sealing portion 23 is folded multiple times.
본 발명의 과제는, 실링부가 복수 회 폴딩되어 있더라도 절연 저항의 저하가 발생하지 않는, 또는 절연 저항의 저하가 최소화 되는 폴딩 구조를 갖는 이차 전지를 제공하는 것이다.The object of the present invention is to provide a secondary battery having a folding structure in which the insulation resistance does not decrease even if the sealing portion is folded multiple times, or the decrease in the insulation resistance is minimized.
일 예에서 이차 전지는 전극 조립체, 상기 전극 조립체를 수용하는 수용부와, 상기 수용부의 적어도 일부를 감싸도록 형성되어 상기 수용부를 밀봉하는 밀봉부를 갖는 파우치형 외장재를 포함하고, 상기 밀봉부는 상기 밀봉부의 외측 말단에서 상기 수용부를 향해 제1 거리만큼 이격되는 제1 폴딩 라인을 따라 상기 밀봉부의 외측 말단이 상기 수용부를 향해 접혀 마련되는 제1 폴딩 부분, 및 상기 제1 폴딩 라인에서 상기 수용부를 향해 제2 거리만큼 이격되는 제2 폴딩 라인을 따라 상기 제1 폴딩 부분이 상기 수용부를 향해 접혀 마련되는 제2 폴딩 부분을 포함하고, 상기 밀봉부는 상기 밀봉부의 외측 말단에서 상기 수용부를 향해 소정의 거리만큼 이격되는 소정의 라인을 실링 라인이라 할 때, 상기 밀봉부의 외측 말단에서 상기 실링 라인까지 융착으로 실링되어 형성되는 실링 부분을 포함하고, 상기 밀봉부의 외측 말단에서 상기 수용부까지의 거리를 상기 밀봉부의 폭이라 할 때, 상기 실링 라인에서 상기 수용부까지의 거리는 상기 밀봉부의 폭의 45% 내지 55%일 수 있다.In one example, the secondary battery includes an electrode assembly, a pouch-type exterior material having a receiving portion for accommodating the electrode assembly, and a sealing portion formed to surround at least a portion of the accommodating portion to seal the accommodating portion, wherein the sealing portion is a portion of the sealing portion. A first folding portion provided by folding the outer end of the sealing portion toward the receiving portion along a first folding line spaced apart from the outer end by a first distance toward the receiving portion, and a second folding portion provided from the first folding line toward the receiving portion. The first folding portion includes a second folding portion provided by folding the first folding portion toward the receiving portion along a second folding line spaced apart by a distance, and the sealing portion is spaced a predetermined distance from an outer end of the sealing portion toward the receiving portion. When a predetermined line is referred to as a sealing line, it includes a sealing portion formed by fusion sealing from the outer end of the sealing portion to the sealing line, and the distance from the outer end of the sealing portion to the receiving portion is referred to as the width of the sealing portion. When doing so, the distance from the sealing line to the receiving part may be 45% to 55% of the width of the sealing part.
다른 일 예에서 상기 밀봉부의 외측 말단에서 상기 제1 폴딩 라인까지의 거리는 상기 밀봉부의 외측 말단에서 상기 실링 라인까지의 거리의 60% 내지 80%일 수 있다. In another example, the distance from the outer end of the sealing part to the first folding line may be 60% to 80% of the distance from the outer end of the sealing part to the sealing line.
또 다른 일 예에서 상기 수용부에서 상기 제2 폴딩 라인까지의 거리는 상기 실링 라인에서 상기 수용부까지의 거리의 18% 내지 34%일 수 있다.In another example, the distance from the receiving part to the second folding line may be 18% to 34% of the distance from the sealing line to the receiving part.
또 다른 일 예에서 상기 실링 라인은 상기 제1 폴딩 라인과 상기 제2 폴딩 라인의 사이에 위치할 수 있다. In another example, the sealing line may be located between the first folding line and the second folding line.
또 다른 일 예에서 이차 전지는 전극 조립체, 및 상기 전극 조립체를 수용하는 수용부와, 상기 수용부의 적어도 일부를 감싸도록 형성되어 상기 수용부를 밀봉하는 밀봉부를 갖는 파우치형 외장재를 포함하고, 상기 밀봉부는 상기 밀봉부의 외측 말단에서 상기 수용부를 향해 제1 거리만큼 이격되고 상기 밀봉부의 외측 말단과 나란하게 마련되는 제1 폴딩 라인을 따라 상기 밀봉부의 외측 말단이 상기 수용부를 향해 접혀 마련되는 제1 폴딩 부분, 및 상기 제1 폴딩 라인에서 상기 수용부를 향해 제2 거리만큼 이격되고 상기 제1 폴딩 라인과 나란하게 마련되는 제2 폴딩 라인을 따라 상기 제1 폴딩 부분이 상기 수용부를 향해 접혀 마련되는 제2 폴딩 부분을 포함하고, 상기 밀봉부의 외측 말단에서 상기 수용부까지의 거리를 상기 밀봉부의 폭이라 할 때, 상기 제1 거리는 상기 밀봉부의 폭의 34.65% 내지 42.35%이고, 상기 제2 거리는 상기 밀봉부의 폭의 43.65% 내지 53.35%일 수 있다.In another example, a secondary battery includes an electrode assembly, a pouch-type exterior material having an accommodating portion for accommodating the electrode assembly, and a sealing portion formed to surround at least a portion of the accommodating portion to seal the accommodating portion, and the sealing portion A first folding portion in which the outer end of the sealing portion is folded toward the receiving portion along a first folding line that is spaced apart from the outer end of the sealing portion toward the receiving portion by a first distance and is provided in parallel with the outer end of the sealing portion, and a second folding portion in which the first folding portion is folded toward the receiving portion along a second folding line that is spaced apart from the first folding line toward the receiving portion by a second distance and is parallel to the first folding line. It includes, and when the distance from the outer end of the sealing portion to the receiving portion is referred to as the width of the sealing portion, the first distance is 34.65% to 42.35% of the width of the sealing portion, and the second distance is 34.65% to 42.35% of the width of the sealing portion. It may be 43.65% to 53.35%.
또 다른 일 예에서 상기 밀봉부의 외측 말단에서 상기 수용부를 향해 소정의 거리만큼 이격되고 상기 밀봉부의 외측 말단과 나란하게 마련되는 소정의 라인을 실링 라인이라 할 때, 상기 밀봉부는 상기 밀봉부의 외측 말단에서 상기 실링 라인까지 융착으로 실링되어 있고, 상기 실링 라인은 상기 제1 폴딩 라인과 상기 제2 폴딩 라인의 사이에 위치하고, 상기 제2 폴딩 라인에서 상기 실링 라인까지의 거리는 상기 밀봉부의 폭의 20% 이상일 수 있다.In another example, when a predetermined line spaced a predetermined distance from the outer end of the sealing part toward the receiving part and provided parallel to the outer end of the sealing part is referred to as a sealing line, the sealing part is located at the outer end of the sealing part. The sealing line is sealed by fusion, the sealing line is located between the first folding line and the second folding line, and the distance from the second folding line to the sealing line is 20% or more of the width of the sealing portion. You can.
또 다른 일 예에서 상기 밀봉부의 외측 말단에서 상기 수용부를 향해 소정의 거리만큼 이격되고 상기 밀봉부의 외측 말단과 나란하게 마련되는 소정의 라인을 실링 라인이라 할 때, 상기 밀봉부는 상기 밀봉부의 외측 말단에서 상기 실링 라인까지 융착으로 실링되어 있고, 상기 실링 라인은 상기 제1 폴딩 라인과 상기 제2 폴딩 라인의 사이에 위치하고, 상기 제2 폴딩 라인에서 상기 실링 라인까지의 거리는 상기 밀봉부의 외측 말단에서 상기 실링 라인까지의 거리의 40% 이상일 수 있다.In another example, when a predetermined line spaced a predetermined distance from the outer end of the sealing part toward the receiving part and provided parallel to the outer end of the sealing part is referred to as a sealing line, the sealing part is located at the outer end of the sealing part. The sealing line is sealed by fusion, the sealing line is located between the first folding line and the second folding line, and the distance from the second folding line to the sealing line is from the outer end of the sealing portion to the sealing line. It may be more than 40% of the distance to the line.
또 다른 일 예에서 상기 밀봉부의 외측 말단에서 상기 수용부를 향해 소정의 거리만큼 이격되고 상기 밀봉부의 외측 말단과 나란하게 마련되는 소정의 라인을 실링 라인이라 할 때, 상기 밀봉부는 상기 밀봉부의 외측 말단에서 상기 실링 라인까지는 융착으로 실링되어 있고, 상기 실링 라인에서 상기 수용부까지는 융착되어 있지 않고, 상기 실링 라인은 상기 제1 폴딩 라인과 상기 제2 폴딩 라인의 사이에 위치하고, 상기 실링 라인에서 상기 수용부까지의 거리는 상기 밀봉부의 폭의 40% 이상일 수 있다.In another example, when a predetermined line spaced a predetermined distance from the outer end of the sealing part toward the receiving part and provided parallel to the outer end of the sealing part is referred to as a sealing line, the sealing part is located at the outer end of the sealing part. The sealing line is sealed by fusion, but the sealing line to the receiving portion is not fused, the sealing line is located between the first folding line and the second folding line, and the sealing line is connected to the receiving portion. The distance to may be 40% or more of the width of the sealing portion.
또 다른 일 예에서 이차 전지는 전극 조립체, 및 상기 전극 조립체를 수용하는 수용부와, 상기 수용부의 적어도 일부를 감싸도록 형성되어 상기 수용부를 밀봉하는 밀봉부를 갖는 파우치형 외장재를 포함하고, 상기 밀봉부는 상기 밀봉부의 외측 말단에서 상기 수용부를 향해 제1 거리만큼 이격되고 상기 밀봉부의 외측 말단과 나란하게 마련되는 제1 폴딩 라인을 따라 상기 밀봉부의 외측 말단이 상기 수용부를 향해 접혀 마련되는 제1 폴딩 부분, 및 상기 제1 폴딩 라인에서 상기 수용부를 향해 제2 거리만큼 이격되고 상기 제1 폴딩 라인과 나란하게 마련되는 제2 폴딩 라인을 따라 상기 제1 폴딩 부분이 상기 수용부를 향해 접혀 마련되는 제2 폴딩 부분을 포함하고, 상기 밀봉부는 상기 밀봉부의 외측 말단에서 상기 수용부를 향해 소정의 거리만큼 이격되고 상기 밀봉부의 외측 말단과 나란하게 마련되는 소정의 라인을 실링 라인이라 할 때, 상기 밀봉부의 외측 말단에서 상기 실링 라인까지 융착으로 실링되어 있고, 상기 제2 폴딩 라인에서 상기 실링 라인까지의 거리는 상기 밀봉부의 외측 말단에서 상기 실링 라인까지의 거리의 40% 이상일 수 있다.In another example, a secondary battery includes an electrode assembly, a pouch-type exterior material having an accommodating portion for accommodating the electrode assembly, and a sealing portion formed to surround at least a portion of the accommodating portion to seal the accommodating portion, and the sealing portion A first folding portion in which the outer end of the sealing portion is folded toward the receiving portion along a first folding line that is spaced apart from the outer end of the sealing portion toward the receiving portion by a first distance and is provided in parallel with the outer end of the sealing portion, and a second folding portion in which the first folding portion is folded toward the receiving portion along a second folding line that is spaced apart from the first folding line toward the receiving portion by a second distance and is parallel to the first folding line. Includes, wherein the sealing part is spaced a predetermined distance from the outer end of the sealing part toward the receiving part, and when a predetermined line provided parallel to the outer end of the sealing part is referred to as a sealing line, the sealing part is separated from the outer end of the sealing part by a predetermined distance. The sealing line is sealed by fusion, and the distance from the second folding line to the sealing line may be 40% or more of the distance from the outer end of the sealing portion to the sealing line.
또 다른 일 예에서 상기 실링 라인은 상기 제1 폴딩 라인과 상기 제2 폴딩 라인의 사이에 위치할 수 있다. In another example, the sealing line may be located between the first folding line and the second folding line.
본 발명에 의하면, 실링 범위나 폴딩 위치의 최적화를 통해, 밀봉부가 복수 회 폴딩되어 있더라도 절연 저항의 저하가 발생하지 않거나, 또는 절연 저항의 저하가 최소화 될 수 있다. According to the present invention, through optimization of the sealing range or folding position, a decrease in insulation resistance does not occur or the decrease in insulation resistance can be minimized even if the sealing portion is folded multiple times.
또한 본 발명에 의하면, 밀봉부 중 융착되어 있지 않은 부분(Die-seal gap)을 충분하게 확보함으로써 절연 저항의 불량률을 개선시킬 수 있다.In addition, according to the present invention, the defective rate of insulation resistance can be improved by sufficiently securing the portion of the seal that is not fused (die-seal gap).
도 1은 파우치형 이차 전지의 일례를 도시하고 있는 도면이다. 1 is a diagram showing an example of a pouch-type secondary battery.
도 2는 본 발명의 일 실시예에 따른 이차 전지를 도시하고 있는 사시도이다.Figure 2 is a perspective view showing a secondary battery according to an embodiment of the present invention.
도 3 내지 도 6은 도 2의 이차 전지를 제조하는 과정을 순차적으로 도시하고 있는 도면이다.Figures 3 to 6 are diagrams sequentially showing the process of manufacturing the secondary battery of Figure 2.
이하에서는 첨부의 도면을 참조하여 본 발명이 속하는 기술 분야에서 통상의 지식을 가진 자가 용이하게 실시할 수 있도록 본 발명의 바람직한 실시예를 상세하게 설명한다. 그러나 본 발명은 여러 가지 상이한 형태로 구현될 수 있으며 이하의 실시예에 의해 제한되거나 한정되는 것은 아니다. Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the present invention. However, the present invention may be implemented in various different forms and is not limited or restricted by the following examples.
본 발명을 명확하게 설명하기 위해서 설명과 관계없는 부분 또는 본 발명의 요지를 불필요하게 흐릴 수 있는 관련 공지 기술에 대한 상세한 설명은 생략하였으며, 본 명세서에서 각 도면의 구성요소들에 참조 부호를 부가함에 있어서는, 명세서 전체를 통하여 동일 또는 유사한 구성요소에 대해서는 동일 또는 유사한 참조 부호를 붙이도록 한다In order to clearly explain the present invention, detailed descriptions of parts unrelated to the description or related known technologies that may unnecessarily obscure the gist of the present invention have been omitted, and reference signs are added to components in each drawing in this specification. In this regard, identical or similar reference signs are used to designate identical or similar components throughout the specification.
또한, 본 명세서 및 특허청구범위에 사용된 용어나 단어는 통상적이거나 사전적인 의미로 한정하여 해석되어서는 안되며, 발명자는 그 자신의 발명을 가장 최선의 방법으로 설명하기 위해 용어의 개념을 적절하게 정의할 수 있다는 원칙에 입각하여 본 발명의 기술적 사상에 부합하는 의미와 개념으로 해석되어야만 한다.In addition, terms or words used in this specification and patent claims should not be construed as limited to their usual or dictionary meanings, and the inventor should appropriately define the concept of terms in order to explain his or her invention in the best way. It must be interpreted with meaning and concept consistent with the technical idea of the present invention based on the principle that it can be done.
도 2는 본 발명의 일 실시예에 따른 이차 전지를 도시하고 있는 사시도이고, 도 3 내지 도 6은 도 2의 이차 전지를 제조하는 과정을 순차적으로 도시하고 있는 도면이다. 본 실시예에 따른 이차 전지는 도 3에 도시되어 있듯이 전극 조립체(110)와 외장재(120)를 포함할 수 있다. 도 3은 도 2의 이차 전지 중 밀봉부(140; 141, 142)가 폴딩되기 전을 도시하고 있는 사시도이다. Figure 2 is a perspective view showing a secondary battery according to an embodiment of the present invention, and Figures 3 to 6 are diagrams sequentially showing the process of manufacturing the secondary battery of Figure 2. The secondary battery according to this embodiment may include an electrode assembly 110 and an exterior material 120, as shown in FIG. 3 . FIG. 3 is a perspective view illustrating the secondary battery of FIG. 2 before the sealing portions 140 (141, 142) are folded.
전극 조립체(110; 도 1의 도면부호 2 참조)는 전극과 분리막이 교대로 적층되어 형성될 수 있다. 전극은 양극과 음극을 포함할 수 있다. 전극 조립체(110)는 전극에 연결되는 전극탭(도 1 참조)을 구비할 수 있다. 전극탭은 별도로 마련될 수도 있고, 전극을 구성하는 집전체의 일부로서 마련될 수도 있다.The electrode assembly 110 (see reference numeral 2 in FIG. 1) may be formed by alternately stacking electrodes and separators. Electrodes may include an anode and a cathode. The electrode assembly 110 may include an electrode tab (see FIG. 1) connected to the electrode. The electrode tab may be provided separately, or may be provided as part of the current collector constituting the electrode.
외장재(120)는 라미네이트 시트의 성형으로 형성되어 전극 조립체(110)를 수용하는 파우치형 외장재(120)일 수 있다. 전극 조립체(110)의 수용을 위해서 파우치형 외장재(120)는 수용부(130)를 포함할 수 있다. 파우치형 외장재(120)는 서로 마주보게 배치되는 2개의 외장재가 전극 조립체(110)의 수용 상태에서 서로 밀봉되게 결합되어 마련될 수 있다. 이때에는 2개의 외장재의 테두리가 전체적으로 밀봉될 수 있다. 이런 밀봉으로 밀봉부(140)가 형성될 수 있다. 또는 파우치형 외장재는 1개의 외장재의 접힘으로 형성될 수도 있다(도 1 참조). 이때에는 접힌 부분을 제외하고 1개의 외장재의 나머지 테두리가 밀봉될 수 있다. 도 3 등에는 1개의 만입 형상 부분으로 수용부(130)를 형성하는 외장재(120)가 예시되어 있다. The exterior material 120 may be a pouch-type exterior material 120 that is formed by molding a laminate sheet and accommodates the electrode assembly 110. To accommodate the electrode assembly 110, the pouch-type exterior material 120 may include a receiving portion 130. The pouch-type exterior material 120 may be prepared by sealing two exterior materials arranged to face each other while being accommodated in the electrode assembly 110 . In this case, the edges of the two exterior materials can be completely sealed. The sealing portion 140 can be formed through this sealing. Alternatively, the pouch-type exterior material may be formed by folding one exterior material (see Figure 1). In this case, the remaining edge of one exterior material, excluding the folded portion, may be sealed. 3 and other examples illustrate the exterior material 120 forming the receiving portion 130 with one indented portion.
파우치형 외장재(120)는 알루미늄 등의 금속층, 금속층의 내면에 배치되는 제1 수지층, 및 금속층의 외면에 배치되는 제2 수지층을 포함하는 라미네이트 시트로부터 제조될 수 있다. 제1 수지층은 폴리프로필렌(Polypropylene, PP)으로 형성되는 층일 수 있다. 제1 수지층에는 높은 절연성 및 내식성이 요구되는데, 이런 요구를 만족하는 다른 수지로 제1 수지층이 형성될 수도 있다. 제2 수지층은 폴리에틸렌 테레프탈레이트(polyethylene terephthalate, PET)로 형성되는 층일 수 있다. 제2 수지층은 이차 전지를 보호하면서도 이차 전지를 전기적으로 절연시킬 필요가 있는데, 이런 요구를 만족하는 다른 수지로 제2 수지층이 형성될 수도 있다. The pouch-type exterior material 120 may be manufactured from a laminate sheet including a metal layer such as aluminum, a first resin layer disposed on the inner surface of the metal layer, and a second resin layer disposed on the outer surface of the metal layer. The first resin layer may be a layer formed of polypropylene (PP). High insulation and corrosion resistance are required for the first resin layer, and the first resin layer may be formed of another resin that satisfies these requirements. The second resin layer may be a layer formed of polyethylene terephthalate (PET). The second resin layer needs to protect the secondary battery and electrically insulate the secondary battery, and the second resin layer may be formed of another resin that satisfies these requirements.
밀봉부(140)는 도 3, 4에 도시되어 있듯이 밀봉부(140)의 외측 말단(140a)에서 수용부(130)를 향해 제1 거리(L1)만큼 이격되는 제1 폴딩 라인(F1)을 따라 밀봉부(140)의 외측 말단(140a)이 수용부(130)를 향해 접혀 마련되는 제1 폴딩 부분(141; 도 2, 5 참조)을 포함할 수 있다. 제1 폴딩 라인(F1)은 밀봉부(140)의 외측 말단(140a)과 나란하게 마련될 수 있다. 참고로 도 4는 도 3의 이차 전지의 A-A선에 따른 단면도이다. 도 5는 도 4의 이차 전지 중 밀봉부의 외측 말단이 제1 폴딩 라인을 따라 폴딩되어 제1 폴딩 부분이 형성된 이차 전지를 도시하고 있는 단면도이다. 도 4, 5에는 도시의 편의상 전극 조립체가 미도시되어 있다. As shown in FIGS. 3 and 4, the sealing portion 140 has a first folding line (F 1 ) spaced apart from the outer end 140a of the sealing portion 140 toward the receiving portion 130 by a first distance (L 1 ). ), the outer end 140a of the sealing portion 140 may include a first folding portion 141 (see FIGS. 2 and 5) that is provided by being folded toward the receiving portion 130. The first folding line (F 1 ) may be provided parallel to the outer end (140a) of the sealing portion (140). For reference, FIG. 4 is a cross-sectional view taken along line AA of the secondary battery of FIG. 3. FIG. 5 is a cross-sectional view showing a secondary battery of FIG. 4 in which the outer end of the sealing portion is folded along a first folding line to form a first folded portion. 4 and 5, the electrode assembly is not shown for convenience of illustration.
밀봉부(140)는 제1 폴딩 라인(F1)에서 수용부(130)를 향해 제2 거리(L2)만큼 이격되는 제2 폴딩 라인(F2)을 따라 제1 폴딩 부분(141)이 수용부(130)를 향해 접혀 마련되는 제2 폴딩 부분(142; 도 2, 6 참조)을 포함할 수 있다. 제2 폴딩 라인(F2)은 제1 폴딩 라인(F1)과 나란하게 마련될 수 있다. 참고로 도 6은 도 5의 이차 전지 중 밀봉부의 제1 폴딩 부분이 제2 폴딩 라인을 따라 폴딩되어 제2 폴딩 부분이 형성된 이차 전지를 도시하고 있는 단면도이다. 도 6에는 도시의 편의상 전극 조립체가 미도시되어 있다.The sealing portion 140 has a first folding portion 141 along a second folding line (F 2 ) spaced apart from the first folding line (F 1 ) by a second distance (L 2 ) toward the receiving portion 130. It may include a second folding portion 142 (see FIGS. 2 and 6) that is folded toward the receiving portion 130. The second folding line (F 2 ) may be provided parallel to the first folding line (F 1 ). For reference, FIG. 6 is a cross-sectional view showing a secondary battery of FIG. 5 in which the first folded portion of the sealing portion is folded along a second folding line to form a second folded portion. In Figure 6, the electrode assembly is not shown for convenience of illustration.
도 4에 도시되어 있듯이 밀봉부(140)의 외측 말단(140a)에서 수용부(130)를 향해 소정의 거리(L3)만큼 이격되는 소정의 라인을 실링 라인(S)이라 할 때, 밀봉부(140)는 밀봉부(140)의 외측 말단(140a)에서 실링 라인(S)까지 융착으로 실링되어 형성되는 실링 부분(151)을 포함할 수 있다. 실링 라인(S)은 밀봉부(140)의 외측 말단(140a)과 나란하게 마련될 수 있다. 실링 라인(S)은 제1 폴딩 라인(F1)과 제2 폴딩 라인(F2)의 사이에 위치할 수 있다. 융착은 열융착일 수 있다.As shown in FIG. 4, when a predetermined line spaced apart from the outer end 140a of the sealing portion 140 toward the receiving portion 130 by a predetermined distance (L 3 ) is referred to as the sealing line (S), the sealing portion 140 may include a sealing portion 151 formed by fusion sealing from the outer end 140a of the sealing portion 140 to the sealing line S. The sealing line (S) may be provided parallel to the outer end (140a) of the sealing portion (140). The sealing line (S) may be located between the first folding line (F 1 ) and the second folding line (F 2 ). The fusion may be heat fusion.
밀봉부(140)의 외측 말단(140a)에서 수용부(130)까지의 거리를 밀봉부(140)의 폭(LW)이라 할 때, 실링 라인(S)에서 수용부(130)까지의 거리(L4)는 밀봉부(140)의 폭(LW)의 45% 내지 55%일 수 있다. 이에 따라 밀봉부(140)의 외측 말단(140a)에서 실링 라인(S)까지의 거리(L3)는 밀봉부(140)의 폭(LW)의 45% 내지 55%일 수 있다. 예를 들어, 위 거리(L4)가 밀봉부(140)의 폭(LW)의 45%라면, 위 거리(L3)는 밀봉부(140)의 폭(LW)의 55%일 수 있다. 위 거리(L4)와 위 거리(L3)의 합은 밀봉부(140)의 폭(LW)과 동일할 수 있다.When the distance from the outer end 140a of the sealing part 140 to the receiving part 130 is referred to as the width (L W ) of the sealing part 140, the distance from the sealing line S to the receiving part 130 (L 4 ) may be 45% to 55% of the width (L W ) of the sealing portion 140 . Accordingly, the distance (L 3 ) from the outer end (140a) of the sealing portion (140) to the sealing line (S) may be 45% to 55% of the width (L W ) of the sealing portion (140). For example, if the upper distance (L 4 ) is 45% of the width (L W ) of the seal 140, the upper distance (L 3 ) may be 55% of the width (L W ) of the seal 140. there is. The sum of the upper distance (L 4 ) and the upper distance (L 3 ) may be equal to the width (L W ) of the sealing portion 140.
예를 들어, 밀봉부(140)의 폭(LW)은 10mm일 수 있고, 밀봉부(140)의 외측 말단(140a)에서 실링 라인(S)까지의 거리(L3)는 밀봉부(140)의 폭(LW)의 50%인 5mm일 수 있다. 또는 밀봉부(140)의 폭(LW)은 10mm일 수 있고, 실링 라인(S)에서 수용부(130)까지의 거리(L4)는 밀봉부(140)의 폭(LW)의 50%인 5mm일 수 있다. For example, the width (L W ) of the sealing portion 140 may be 10 mm, and the distance (L 3 ) from the outer end (140a) of the sealing portion 140 to the sealing line (S) may be 10 mm. ) may be 5 mm, which is 50% of the width (L W ). Alternatively, the width (L W ) of the sealing portion 140 may be 10 mm, and the distance (L 4 ) from the sealing line (S) to the receiving portion 130 may be 50 mm of the width (L W ) of the sealing portion 140. % can be 5mm.
밀봉부(140)는 전술한 실링 부분(151)과 후술할 미실링 부분(밀봉부의 실링 라인~밀봉부와 수용부의 경계; 152, 153)을 포함할 수 있다. 미실링 부분(152, 153) 중 일부(152)는 융착되게 설계되는 것은 아니나 실링 부분(151)의 실링 중에 유입되는 열 등으로 인해 가착될 수 있다. 실링 라인(S)에서 수용부(130)까지의 거리(L4)가 밀봉부(140)의 폭(LW)의 45% 미만이면, 위와 같이 가착되는 가착영역(152)과 제2 폴딩 라인(F2) 사이의 이격 거리를 충분하게 확보하기 어려워서, 제2 폴딩 라인(F2)을 가압하기 위한 폴딩 나이프가 가착영역(152)도 함께 가압할 우려가 있다. 폴딩 나이프가 가착영역(152)을 가압해서 가착영역(152)에 크랙이 발생하면 절연 저항의 불량이 발생될 수 있다. 그리고 밀봉부(140) 중 미실링 부분(153)은 수용부(130)의 내부에서 발생하는 가스로 인해 벌어져서 가스를 수용할 수 있는 공간으로 역할할 수 있는데, 위 거리(L4)가 밀봉부(140)의 폭(LW)의 45% 미만이면, 가스 발생 시에 가스를 수용할 수 있는 공간이 충분하게 형성되지 않을 수 있다. 이는 이차 전지의 고온 저장 내구성의 악화를 초래할 수 있다. The sealing portion 140 may include the sealing portion 151 described above and an unsealed portion (sealing line of the sealing portion ~ boundary between the sealing portion and the receiving portion; 152, 153) to be described later. Some 152 of the unsealed portions 152 and 153 are not designed to be fused, but may be temporarily fused due to heat introduced during the sealing of the sealed portion 151. If the distance L 4 from the sealing line S to the receiving part 130 is less than 45% of the width L W of the sealing part 140, the temporary attachment area 152 and the second folding line are attached as above. Since it is difficult to secure a sufficient separation distance between (F 2 ), there is a risk that the folding knife for pressing the second folding line (F 2 ) will also pressurize the attachment area 152. If the folding knife presses the adhesive area 152 and a crack occurs in the adhesive area 152, a defect in insulation resistance may occur. In addition, the unsealed portion 153 of the sealing portion 140 may be opened due to the gas generated inside the receiving portion 130 to serve as a space for accommodating the gas, and the above distance L 4 is the sealing portion 153. If it is less than 45% of the width (L W ) of (140), a sufficient space to accommodate gas may not be formed when gas is generated. This may result in deterioration of the high-temperature storage durability of the secondary battery.
실링 라인(S)에서 수용부(130)까지의 거리(L4)가 밀봉부(140)의 폭(LW)의 55% 초과이면, 밀봉부(140)의 외측 말단(140a)에서 실링 라인(S)까지의 거리(L3)가 상대적으로 짧아져서 실링 부분(151)의 폭이 충분하지 않을 우려가 있다. 실링 부분(151)의 폭이 충분하지 않으면 밀봉부(140)의 밀봉 성능이 충분하지 않을 수 있다. If the distance L 4 from the sealing line S to the receiving part 130 is greater than 55% of the width L W of the sealing part 140, the sealing line is formed at the outer end 140a of the sealing part 140. Since the distance L 3 to (S) is relatively short, there is a risk that the width of the sealing portion 151 may not be sufficient. If the width of the sealing portion 151 is not sufficient, the sealing performance of the sealing portion 140 may not be sufficient.
위와 같이 실링 범위 또는 미실링 범위를 최적화 함으로써 밀봉부(140)가 복수 회 폴딩되어 있더라도 절연 저항의 저하가 발생하지 않거나, 또는 절연 저항의 저하가 최소화 될 수 있고, 또한 고온 저장 내구성의 악화나 밀봉 성능의 악화도 방지할 수 있다.By optimizing the sealing range or unsealing range as described above, even if the sealing portion 140 is folded multiple times, a decrease in insulation resistance does not occur, or a decrease in insulation resistance can be minimized, and furthermore, deterioration of high-temperature storage durability or sealing Deterioration in performance can also be prevented.
밀봉부(140)의 외측 말단(140a)에서 제1 폴딩 라인(F1)까지의 거리, 즉 제1 거리(L1)는 밀봉부(140)의 외측 말단(140a)에서 실링 라인(S)까지의 거리(L3)의 60% 내지 80%일 수 있다. 예를 들어, 밀봉부(140)의 외측 말단(140a)에서 실링 라인(S)까지의 거리(L3)는 5mm일 수 있고, 밀봉부(140)의 외측 말단(140a)에서 제1 폴딩 라인(F1)까지의 거리(L1)는 위 거리(L3)의 77%인 3.85mm일 수 있다.The distance from the outer end (140a) of the sealing part 140 to the first folding line (F 1 ), that is, the first distance (L 1 ) is the distance from the outer end (140a) of the sealing part 140 to the sealing line (S) It may be 60% to 80% of the distance to (L 3 ). For example, the distance (L 3 ) from the outer end (140a) of the sealing portion (140) to the sealing line (S) may be 5 mm, and the first folding line from the outer end (140a) of the sealing portion (140) may be 5 mm. The distance (L 1 ) to (F 1 ) may be 3.85 mm, which is 77% of the above distance (L 3 ).
도 5에 도시되어 있듯이 밀봉부(140)의 외측 말단(140a)이 제1 폴딩 라인(F1)을 따라 폴딩되어 제1 폴딩 부분(141)이 형성될 수 있는데, 위 거리(L1; 도 4)가 위 거리(L3; 도 4)의 60% 미만이면, 밀봉부(140) 중 펼쳐진 부분의 상측으로 접혀지는 부분(도 5의 두 층의 밀봉부 중 위쪽 층의 밀봉부 참조)의 길이가 짧아질 수 있다. 접혀지는 부분의 길이가 짧아지면 밀봉부의 폴딩 형상이 안정적으로 유지되기 어려울 수 있다. 위 거리(L1)가 위 거리(L3)의 80% 초과이면, 가착영역(152)과 제1 폴딩 라인(F1) 사이의 이격 거리를 충분하게 확보하기 어려워서, 제1 폴딩 라인(F1)을 가압하기 위한 폴딩 나이프가 가착영역(152)도 함께 가압할 우려가 있다. 폴딩 나이프가 가착영역(152)을 가압해서 가착영역(152)에 크랙이 발생하면 절연 저항의 불량이 발생될 수 있다.As shown in FIG. 5, the outer end 140a of the sealing portion 140 is folded along the first folding line F 1 to form the first folding portion 141, where the upper distance L 1 is shown in FIG. If 4) is less than 60% of the above distance (L 3 ; Figure 4), the part of the sealing part 140 that is folded upward from the unfolded part (see the sealing part of the upper layer of the two layers of sealing parts in Figure 5) The length may be shortened. If the length of the folded part is shortened, it may be difficult to maintain the folded shape of the sealing part stably. If the above distance (L 1 ) exceeds 80% of the above distance (L 3 ), it is difficult to secure a sufficient separation distance between the attachment area 152 and the first folding line (F 1 ), so that the first folding line (F There is a risk that the folding knife for pressurizing the 1 ) may also pressurize the adhesive area 152 . If the folding knife presses the adhesive area 152 and a crack occurs in the adhesive area 152, a defect in insulation resistance may occur.
수용부(130)에서 제2 폴딩 라인(F2)까지의 거리(L6)는 실링 라인(S)에서 수용부(130)까지의 거리(L4)의 18% 내지 34%일 수 있다. 예를 들어, 실링 라인(S)에서 수용부(130)까지의 거리(L4)는 5mm일 수 있고, 수용부(130)에서 제2 폴딩 라인(F2)까지의 거리(L6)는 위 거리(L4)의 26%인 1.3mm일 수 있다.The distance (L 6 ) from the receiving part 130 to the second folding line (F 2 ) may be 18% to 34% of the distance (L 4 ) from the sealing line (S) to the receiving part 130. For example, the distance (L 4 ) from the sealing line (S) to the receiving part 130 may be 5 mm, and the distance (L 6 ) from the receiving part 130 to the second folding line (F 2 ) may be 5 mm. It may be 1.3 mm, which is 26% of the above distance (L 4 ).
위 거리(L6)가 위 거리(L4)의 18% 미만이면, 제2 폴딩 라인(F2)과 수용부(130) 사이의 이격 거리가 너무 짧아져서, 제2 폴딩 라인(F2)을 가압하기 위한 폴딩 나이프가 수용부(130)와의 간섭 없이 원활하게 제2 폴딩 라인(F2)을 가압하기 어려울 수 있다. 위 거리(L6)가 위 거리(L4)의 34% 초과이면, 밀봉부(140) 중 수용부(130)에 인접하게 위치하고 폴딩되지 않는 부분(도 6 중 F2의 왼쪽 부분 참조)의 길이가 길어져서, 이차 전지가 차지하는 전체 부피가 증가될 수 있다. 전체 부피의 증가는 부피 에너지 밀도의 감소를 초래할 수 있다. If the upper distance (L 6 ) is less than 18% of the upper distance (L 4 ), the separation distance between the second folding line (F 2 ) and the receiving portion 130 becomes too short, so that the second folding line (F 2 ) It may be difficult for the folding knife to press the second folding line F 2 smoothly without interfering with the receiving portion 130 . If the upper distance (L 6 ) is greater than 34% of the upper distance (L 4 ), the portion of the sealing portion 140 located adjacent to the receiving portion 130 and not folded (see the left portion of F 2 in FIG. 6) As the length becomes longer, the overall volume occupied by the secondary battery may increase. An increase in total volume may result in a decrease in volumetric energy density.
밀봉부(140)의 외측 말단(140a)에서 제1 폴딩 라인(F1)까지의 거리인 제1 거리(L1) 및, 제1 폴딩 라인(F1)에서 제2 폴딩 라인(F2)까지의 거리인 제2 거리(L2)와 관련하여, 밀봉부(140)의 폭(LW)에 대한 제1 거리(L1)의 비율은 34.65% 내지 42.35%이고, 밀봉부(140)의 폭(LW)에 대한 제2 거리(L2)의 비율은 43.65% 내지 53.35%일 수 있다. 본 실시예의 이차 전지의 경우 폴딩 위치의 최적화를 통해, 밀봉부(140)가 복수 회 폴딩되어 있더라도 절연 저항의 저하가 발생하지 않거나, 또는 절연 저항의 저하가 최소화 될 수 있다. 본 실시예의 이차 전지의 경우 100MΩ에서 절연 저항 불량률이 0.6%로 확인되었다.A first distance (L 1 ), which is the distance from the outer end (140a) of the sealing portion (140) to the first folding line (F 1 ), and a second folding line (F 2 ) from the first folding line (F 1 ). With respect to the second distance L 2 , which is the distance to, the ratio of the first distance L 1 to the width L W of the seal 140 is 34.65% to 42.35%, and The ratio of the second distance (L 2 ) to the width (L W ) may be 43.65% to 53.35%. In the case of the secondary battery of this embodiment, through optimization of the folding position, a decrease in insulation resistance may not occur or a decrease in insulation resistance may be minimized even if the sealing portion 140 is folded multiple times. In the case of the secondary battery of this example, the insulation resistance defect rate was confirmed to be 0.6% at 100 MΩ.
예를 들어, 제1 거리(L1)는 3.85mm일 수 있고, 제2 거리(L2)는 4.85mm일 수 있고, 밀봉부(140)의 폭(LW)은 10mm일 수 있다. 이때 밀봉부(140)의 폭(LW)에 대한 제1 거리(L1)의 비율은 38.5%일 수 있고, 밀봉부(140)의 폭(LW)에 대한 제2 거리(L2)의 비율은 48.5%일 수 있다.For example, the first distance L 1 may be 3.85 mm, the second distance L 2 may be 4.85 mm, and the width L W of the sealing portion 140 may be 10 mm. At this time, the ratio of the first distance (L 1 ) to the width (L W ) of the sealing portion 140 may be 38.5%, and the second distance (L 2 ) to the width (L W ) of the sealing portion 140 The ratio may be 48.5%.
밀봉부(140)의 폭(LW)에 대한, 제2 폴딩 라인(F2)에서 실링 라인(S)까지의 거리(L5)에 대한 비율은 20% 이상일 수 있다. 예를 들어, 제2 폴딩 라인(F2)에서 실링 라인(S)까지의 거리(L5)는 3.7mm일 수 있고, 이때 밀봉부(140)의 폭(LW)에 대한 위 거리(L5)의 비율은 37%일 수 있다.The ratio of the distance (L 5 ) from the second folding line (F 2 ) to the sealing line (S) to the width (L W ) of the sealing portion 140 may be 20% or more. For example, the distance (L 5 ) from the second folding line (F 2 ) to the sealing line (S) may be 3.7 mm, where the distance (L) relative to the width (L W ) of the sealing portion 140 5 ) the rate may be 37%.
제2 폴딩 라인(F2)에서 실링 라인(S)까지의 거리(L5)는 밀봉부(140)의 외측 말단(140a)에서 실링 라인(S)까지의 거리(L3)의 40% 이상일 수 있다. The distance (L 5 ) from the second folding line (F 2 ) to the sealing line (S) is 40% or more of the distance (L 3 ) from the outer end (140a) of the sealing portion 140 to the sealing line (S). You can.
밀봉부 중 일부(밀봉부의 외측 말단~밀봉부의 실링 라인; 151)는 외장재 중 제1 수지층(예: PP) 간의 융착으로 인해 실링될 수 있다. 밀봉부 중 나머지(밀봉부의 실링 라인~밀봉부와 수용부의 경계; 152, 153)의 일부(152)도 융착영역(151; 실링 부분)의 융착 중에 유입되는 열 등으로 인해 가착될 수 있다. 이와 같은 가착영역(152)은 융착영역(151)의 대략 20% 정도 발생될 수도 있다(예. 5mm의 융착영역에 대해 1mm의 가착영역이 발생될 수 있음). 이때 제2 폴딩 부분(142; 도 6 참조)을 형성하기 위한 폴딩 나이프와 가착영역(152) 사이에서 간섭이 발생하면 제1 수지층에 크랙이 발생하여 절연 저항의 불량이 발생될 수 있다. 이런 불량의 발생을 억제하기 위해 가착영역(L3의 20%)의 2배 이상을 위 거리(L5)로 설정하는 것이 바람직할 수 있다. A portion of the sealing portion (outer end of the sealing portion ~ sealing line of the sealing portion 151) may be sealed due to fusion between the first resin layers (eg, PP) of the exterior material. A portion 152 of the remainder of the sealing portion (sealing line of the sealing portion ~ boundary between the sealing portion and the receiving portion; 152, 153) may also be temporarily fused due to heat introduced during fusion of the fusion area 151 (sealing portion). Such a temporary adhesion area 152 may be generated in approximately 20% of the fusion area 151 (e.g., a 1 mm adhesive area may be generated for a 5 mm fused area). At this time, if interference occurs between the folding knife for forming the second folding portion 142 (see FIG. 6) and the adhesive area 152, cracks may occur in the first resin layer, which may result in a defect in insulation resistance. To suppress the occurrence of such defects, it may be desirable to set the above distance (L 5 ) to more than twice the adhesive area (20% of L 3 ).
예를 들어, 제2 폴딩 라인(F2)에서 실링 라인(S)까지의 거리(L5)는 3.7mm일 수 있고, 제3 거리(L3)는 5mm일 수 있고, 이때 위 거리(L5)는 제1 거리(L1)의 74%일 수 있다. For example, the distance (L 5 ) from the second folding line (F 2 ) to the sealing line (S) may be 3.7 mm, and the third distance (L 3 ) may be 5 mm, where the above distance (L 5 ) may be 74% of the first distance (L 1 ).
밀봉부(140)가 밀봉부(140)의 외측 말단(140a)에서 실링 라인(S)까지는 융착으로 실링되어 있고, 실링 라인(S)에서 수용부(130)까지는 융착되어 있지 않을 때(가착영역은 융착이 예정되어 있는 융착영역과 달리 융착이 예정되어 있던 영역은 아니라고 볼 수 있으므로 이번 설명에서 융착되어 있지 않은 영역으로 본다), 밀봉부(140)의 폭(LW)에 대한, 실링 라인(S)에서 수용부(130)까지의 거리(L4)에 대한 비율은 40% 이상일 수 있다. 본 실시예의 이차 전지는 밀봉부(140) 중 융착영역(151)과 가착영역(152) 외에 융착되어 있지 않은 부분(Die-seal gap; 153)을 충분하게 확보함으로써 절연 저항의 불량률을 개선시킬 수 있다. When the sealing portion 140 is sealed by fusion from the outer end 140a of the sealing portion 140 to the sealing line S, but is not fused from the sealing line S to the receiving portion 130 (temporarily bonded area) (Unlike the fusion area where fusion is scheduled, it can be seen that it is not an area where fusion was scheduled, so it is regarded as an area that is not fused in this description), and the sealing line ( The ratio of the distance (L 4 ) from S) to the receiving portion 130 may be 40% or more. The secondary battery of this embodiment can improve the defect rate of insulation resistance by sufficiently securing the non-fused portion (die-seal gap; 153) in addition to the fusion area 151 and the adhesive area 152 of the sealing portion 140. there is.
예를 들어, 실링 라인(S)에서 수용부(130)까지의 거리(L4)는 5mm일 수 있고, 이때 밀봉부(140)의 폭(LW)에 대한 위 거리(L4)의 비율은 50%일 수 있다.For example, the distance (L 4 ) from the sealing line (S) to the receiving part 130 may be 5 mm, where the ratio of the above distance (L 4 ) to the width (L W ) of the sealing part 140 may be 50%.
참고로, 위 거리(L4)는 전술한 바와 같이 밀봉부(140)의 폭(LW)의 45% 내지 55%인 것이 더 바람직할 수 있다.For reference, it may be more preferable that the above distance (L 4 ) is 45% to 55% of the width (L W ) of the sealing portion 140 as described above.
한편, 이차 전지의 절연 저항은 음극과 외장재의 금속층(예. 알루미늄 층) 사이에 전압(예: 25V)을 인가하여 측정되는 전류값으로부터 산출될 수 있다(R = V/I). 예를 들어, 정상 상태(전해액과 금속층 사이에서 접촉이 발생하지 않은 상태)에선 전류의 소모가 확인되지 않을 것이고, 불량 상태(전해액과 금속층 사이에서 접촉이 발생하여 금속층 표면에서 화학반응에 의한 전류의 소모가 발생하는 상태)에선 전류의 소모가 확인될 것이다. 그리고 이차 전지의 절연 전압은 양극과 외장재의 금속층(예. 알루미늄 층) 사이의 전압값을 측정해서 획득될 수 있다. 예를 들어, 정상 상태(전해액과 금속층 사이에서 접촉이 발생하지 않은 상태)에선 전압차가 측정되지 않을 것이고, 불량 상태(전해액과 금속층 사이에서 접촉이 발생한 상태)에선 양극과 금속층 사이에서 전위차가 측정될 것이다.Meanwhile, the insulation resistance of a secondary battery can be calculated from the current value measured by applying a voltage (e.g., 25V) between the cathode and the metal layer (e.g., aluminum layer) of the exterior material (R = V/I). For example, in a normal state (a state in which no contact occurs between the electrolyte and the metal layer), current consumption will not be confirmed, and in a defective state (a state in which contact occurs between the electrolyte and the metal layer, current consumption due to a chemical reaction on the surface of the metal layer) will not be observed. In a state where consumption occurs, the consumption of current will be confirmed. And the insulation voltage of the secondary battery can be obtained by measuring the voltage value between the anode and the metal layer (eg, aluminum layer) of the exterior material. For example, in a normal state (a state in which no contact occurs between the electrolyte and the metal layer), the voltage difference will not be measured, and in a defective state (a state in which contact occurs between the electrolyte and the metal layer), the potential difference will not be measured between the anode and the metal layer. will be.
참고로 도 4의 T는 수용부(130)의 두께를 의미하며, 8.55mm일 수 있다.For reference, T in FIG. 4 refers to the thickness of the receiving portion 130, which may be 8.55 mm.
이상의 설명은 본 발명의 기술 사상을 예시적으로 설명한 것에 불과한 것으로서, 본 발명이 속하는 기술 분야에서 통상의 지식을 가진 자라면 본 발명의 본질적인 특성에서 벗어나지 않는 범위에서 다양한 수정 및 변형이 가능할 것이다.The above description is merely an illustrative explanation of the technical idea of the present invention, and various modifications and variations will be possible to those skilled in the art without departing from the essential characteristics of the present invention.
따라서, 본 발명에 개시된 실시예들은 본 발명의 기술 사상을 한정하기 위한 것이 아니라 설명하기 위한 것이고, 이러한 실시예에 의하여 본 발명의 기술 사상의 범위가 한정되는 것은 아니다.Accordingly, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention, but are for illustrative purposes, and the scope of the technical idea of the present invention is not limited by these embodiments.
본 발명의 보호 범위는 아래의 청구범위에 의하여 해석되어야 하며, 그와 동등한 범위 내에 있는 모든 기술 사상은 본 발명의 권리범위에 포함되는 것으로 해석되어야 할 것이다.The scope of protection of the present invention should be interpreted in accordance with the claims below, and all technical ideas within the equivalent scope should be construed as being included in the scope of rights of the present invention.

Claims (10)

  1. 전극 조립체; 및electrode assembly; and
    상기 전극 조립체를 수용하는 수용부와, 상기 수용부의 적어도 일부를 감싸도록 형성되어 상기 수용부를 밀봉하는 밀봉부를 갖는 파우치형 외장재를 포함하고,It includes a pouch-type exterior material having an accommodating portion for accommodating the electrode assembly, and a sealing portion formed to surround at least a portion of the accommodating portion to seal the accommodating portion,
    상기 밀봉부는, The sealing part,
    상기 밀봉부의 외측 말단에서 상기 수용부를 향해 제1 거리만큼 이격되는 제1 폴딩 라인을 따라 상기 밀봉부의 외측 말단이 상기 수용부를 향해 접혀 마련되는 제1 폴딩 부분; 및a first folding portion provided by folding the outer end of the sealing portion toward the receiving portion along a first folding line spaced apart from the outer end of the sealing portion by a first distance toward the receiving portion; and
    상기 제1 폴딩 라인에서 상기 수용부를 향해 제2 거리만큼 이격되는 제2 폴딩 라인을 따라 상기 제1 폴딩 부분이 상기 수용부를 향해 접혀 마련되는 제2 폴딩 부분을 포함하고,A second folding portion is provided by folding the first folding portion toward the receiving portion along a second folding line spaced apart from the first folding line by a second distance toward the receiving portion,
    상기 밀봉부는,The sealing part,
    상기 밀봉부의 외측 말단에서 상기 수용부를 향해 소정의 거리만큼 이격되는 소정의 라인을 실링 라인이라 할 때, 상기 밀봉부의 외측 말단에서 상기 실링 라인까지 융착으로 실링되어 형성되는 실링 부분을 포함하고,When a predetermined line spaced a predetermined distance from the outer end of the sealing portion toward the receiving portion is referred to as a sealing line, it includes a sealing portion formed by fusion sealing from the outer end of the sealing portion to the sealing line,
    상기 밀봉부의 외측 말단에서 상기 수용부까지의 거리를 상기 밀봉부의 폭이라 할 때,When the distance from the outer end of the sealing portion to the receiving portion is considered the width of the sealing portion,
    상기 실링 라인에서 상기 수용부까지의 거리는 상기 밀봉부의 폭의 45% 내지 55%인, 이차 전지.The secondary battery wherein the distance from the sealing line to the receiving portion is 45% to 55% of the width of the sealing portion.
  2. 청구항 1에 있어서In claim 1
    상기 밀봉부의 외측 말단에서 상기 제1 폴딩 라인까지의 거리는 상기 밀봉부의 외측 말단에서 상기 실링 라인까지의 거리의 60% 내지 80%인, 이차 전지.The secondary battery wherein the distance from the outer end of the sealing part to the first folding line is 60% to 80% of the distance from the outer end of the sealing part to the sealing line.
  3. 청구항 1에 있어서In claim 1
    상기 수용부에서 상기 제2 폴딩 라인까지의 거리는 상기 실링 라인에서 상기 수용부까지의 거리의 18% 내지 34%인, 이차 전지.The secondary battery wherein the distance from the receiving portion to the second folding line is 18% to 34% of the distance from the sealing line to the receiving portion.
  4. 청구항 1에 있어서,In claim 1,
    상기 실링 라인은,The ceiling line is,
    상기 제1 폴딩 라인과 상기 제2 폴딩 라인의 사이에 위치하는, 이차 전지.A secondary battery located between the first folding line and the second folding line.
  5. 전극 조립체; 및electrode assembly; and
    상기 전극 조립체를 수용하는 수용부와, 상기 수용부의 적어도 일부를 감싸도록 형성되어 상기 수용부를 밀봉하는 밀봉부를 갖는 파우치형 외장재를 포함하고,It includes a pouch-type exterior material having an accommodating portion for accommodating the electrode assembly, and a sealing portion formed to surround at least a portion of the accommodating portion to seal the accommodating portion,
    상기 밀봉부는, The sealing part,
    상기 밀봉부의 외측 말단에서 상기 수용부를 향해 제1 거리만큼 이격되고 상기 밀봉부의 외측 말단과 나란하게 마련되는 제1 폴딩 라인을 따라 상기 밀봉부의 외측 말단이 상기 수용부를 향해 접혀 마련되는 제1 폴딩 부분; 및a first folding portion spaced apart from the outer end of the sealing portion toward the receiving portion by a first distance and having the outer end of the sealing portion folded toward the receiving portion along a first folding line provided parallel to the outer end of the sealing portion; and
    상기 제1 폴딩 라인에서 상기 수용부를 향해 제2 거리만큼 이격되고 상기 제1 폴딩 라인과 나란하게 마련되는 제2 폴딩 라인을 따라 상기 제1 폴딩 부분이 상기 수용부를 향해 접혀 마련되는 제2 폴딩 부분을 포함하고,A second folding portion provided by folding the first folding portion toward the receiving portion along a second folding line that is spaced apart from the first folding line toward the receiving portion by a second distance and provided in parallel with the first folding line. Contains,
    상기 밀봉부의 외측 말단에서 상기 수용부까지의 거리를 상기 밀봉부의 폭이라 할 때, When the distance from the outer end of the sealing portion to the receiving portion is considered the width of the sealing portion,
    상기 제1 거리는 상기 밀봉부의 폭의 34.65% 내지 42.35%이고, The first distance is 34.65% to 42.35% of the width of the seal,
    상기 제2 거리는 상기 밀봉부의 폭의 43.65% 내지 53.35%인, 이차 전지.The secondary battery wherein the second distance is 43.65% to 53.35% of the width of the sealing portion.
  6. 청구항 5에 있어서,In claim 5,
    상기 밀봉부의 외측 말단에서 상기 수용부를 향해 소정의 거리만큼 이격되고 상기 밀봉부의 외측 말단과 나란하게 마련되는 소정의 라인을 실링 라인이라 할 때, When a predetermined line spaced a predetermined distance from the outer end of the sealing portion toward the receiving portion and provided parallel to the outer end of the sealing portion is referred to as a sealing line,
    상기 밀봉부는, 상기 밀봉부의 외측 말단에서 상기 실링 라인까지 융착으로 실링되어 있고, The sealing portion is sealed by fusion from the outer end of the sealing portion to the sealing line,
    상기 실링 라인은, 상기 제1 폴딩 라인과 상기 제2 폴딩 라인의 사이에 위치하고,The sealing line is located between the first folding line and the second folding line,
    상기 제2 폴딩 라인에서 상기 실링 라인까지의 거리는 상기 밀봉부의 폭의 20% 이상인, 이차 전지.A secondary battery wherein the distance from the second folding line to the sealing line is 20% or more of the width of the sealing portion.
  7. 청구항 5에 있어서,In claim 5,
    상기 밀봉부의 외측 말단에서 상기 수용부를 향해 소정의 거리만큼 이격되고 상기 밀봉부의 외측 말단과 나란하게 마련되는 소정의 라인을 실링 라인이라 할 때, When a predetermined line spaced a predetermined distance from the outer end of the sealing portion toward the receiving portion and provided parallel to the outer end of the sealing portion is referred to as a sealing line,
    상기 밀봉부는, 상기 밀봉부의 외측 말단에서 상기 실링 라인까지 융착으로 실링되어 있고, The sealing portion is sealed by fusion from the outer end of the sealing portion to the sealing line,
    상기 실링 라인은, 상기 제1 폴딩 라인과 상기 제2 폴딩 라인의 사이에 위치하고,The sealing line is located between the first folding line and the second folding line,
    상기 제2 폴딩 라인에서 상기 실링 라인까지의 거리는, 상기 밀봉부의 외측 말단에서 상기 실링 라인까지의 거리의 40% 이상인, 이차 전지.The secondary battery wherein the distance from the second folding line to the sealing line is 40% or more of the distance from the outer end of the sealing portion to the sealing line.
  8. 청구항 5에 있어서,In claim 5,
    상기 밀봉부의 외측 말단에서 상기 수용부를 향해 소정의 거리만큼 이격되고 상기 밀봉부의 외측 말단과 나란하게 마련되는 소정의 라인을 실링 라인이라 할 때, When a predetermined line spaced a predetermined distance from the outer end of the sealing portion toward the receiving portion and provided parallel to the outer end of the sealing portion is referred to as a sealing line,
    상기 밀봉부는, 상기 밀봉부의 외측 말단에서 상기 실링 라인까지는 융착으로 실링되어 있고, 상기 실링 라인에서 상기 수용부까지는 융착되어 있지 않고, The sealing portion is sealed by fusion from the outer end of the sealing portion to the sealing line, and is not fused from the sealing line to the receiving portion,
    상기 실링 라인은, 상기 제1 폴딩 라인과 상기 제2 폴딩 라인의 사이에 위치하고,The sealing line is located between the first folding line and the second folding line,
    상기 실링 라인에서 상기 수용부까지의 거리는 상기 밀봉부의 폭의 40% 이상인, 이차 전지.A secondary battery wherein the distance from the sealing line to the receiving part is 40% or more of the width of the sealing part.
  9. 전극 조립체; 및electrode assembly; and
    상기 전극 조립체를 수용하는 수용부와, 상기 수용부의 적어도 일부를 감싸도록 형성되어 상기 수용부를 밀봉하는 밀봉부를 갖는 파우치형 외장재를 포함하고,It includes a pouch-type exterior material having an accommodating portion for accommodating the electrode assembly, and a sealing portion formed to surround at least a portion of the accommodating portion to seal the accommodating portion,
    상기 밀봉부는, The sealing part,
    상기 밀봉부의 외측 말단에서 상기 수용부를 향해 제1 거리만큼 이격되고 상기 밀봉부의 외측 말단과 나란하게 마련되는 제1 폴딩 라인을 따라 상기 밀봉부의 외측 말단이 상기 수용부를 향해 접혀 마련되는 제1 폴딩 부분; 및a first folding portion spaced apart from the outer end of the sealing portion toward the receiving portion by a first distance and having the outer end of the sealing portion folded toward the receiving portion along a first folding line provided parallel to the outer end of the sealing portion; and
    상기 제1 폴딩 라인에서 상기 수용부를 향해 제2 거리만큼 이격되고 상기 제1 폴딩 라인과 나란하게 마련되는 제2 폴딩 라인을 따라 상기 제1 폴딩 부분이 상기 수용부를 향해 접혀 마련되는 제2 폴딩 부분을 포함하고,A second folding portion provided by folding the first folding portion toward the receiving portion along a second folding line that is spaced apart from the first folding line toward the receiving portion by a second distance and provided in parallel with the first folding line. Contains,
    상기 밀봉부는,The sealing part,
    상기 밀봉부의 외측 말단에서 상기 수용부를 향해 소정의 거리만큼 이격되고 상기 밀봉부의 외측 말단과 나란하게 마련되는 소정의 라인을 실링 라인이라 할 때, 상기 밀봉부의 외측 말단에서 상기 실링 라인까지 융착으로 실링되어 있고, When a predetermined line that is spaced a predetermined distance from the outer end of the sealing portion toward the receiving portion and is provided in parallel with the outer end of the sealing portion is referred to as a sealing line, the sealing line is sealed by fusion from the outer end of the sealing portion to the sealing line. There is,
    상기 제2 폴딩 라인에서 상기 실링 라인까지의 거리는, 상기 밀봉부의 외측 말단에서 상기 실링 라인까지의 거리의 40% 이상인, 이차 전지.The secondary battery wherein the distance from the second folding line to the sealing line is 40% or more of the distance from the outer end of the sealing portion to the sealing line.
  10. 청구항 9에 있어서,In claim 9,
    상기 실링 라인은, The ceiling line is,
    상기 제1 폴딩 라인과 상기 제2 폴딩 라인의 사이에 위치하는, 이차 전지.A secondary battery located between the first folding line and the second folding line.
PCT/KR2023/020793 2022-12-16 2023-12-15 Secondary battery WO2024128872A1 (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
KR20220176561 2022-12-16
KR10-2022-0176561 2022-12-16
KR1020230182678A KR20240095053A (en) 2022-12-16 2023-12-15 Secondary battery
KR10-2023-0182678 2023-12-15

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Citations (5)

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Publication number Priority date Publication date Assignee Title
JP2001283799A (en) * 2000-03-30 2001-10-12 Sony Corp Battery manufacturing method and folding machine therefor
KR20160140554A (en) * 2016-11-28 2016-12-07 주식회사 엘지화학 Pouch Type Secondary Battery and Device Comprising the Same
KR20190054735A (en) * 2017-11-14 2019-05-22 삼성에스디아이 주식회사 Pouch type secondary battery having non-sealing portion
US20210135198A1 (en) * 2017-03-10 2021-05-06 Envision Aesc Energy Devices Ltd. Lithium ion battery
CN113044272A (en) * 2021-03-11 2021-06-29 昆山聚创新能源科技有限公司 Packaging device and packaging method

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001283799A (en) * 2000-03-30 2001-10-12 Sony Corp Battery manufacturing method and folding machine therefor
KR20160140554A (en) * 2016-11-28 2016-12-07 주식회사 엘지화학 Pouch Type Secondary Battery and Device Comprising the Same
US20210135198A1 (en) * 2017-03-10 2021-05-06 Envision Aesc Energy Devices Ltd. Lithium ion battery
KR20190054735A (en) * 2017-11-14 2019-05-22 삼성에스디아이 주식회사 Pouch type secondary battery having non-sealing portion
CN113044272A (en) * 2021-03-11 2021-06-29 昆山聚创新能源科技有限公司 Packaging device and packaging method

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