WO2024080837A1 - Secondary battery - Google Patents

Secondary battery Download PDF

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Publication number
WO2024080837A1
WO2024080837A1 PCT/KR2023/015867 KR2023015867W WO2024080837A1 WO 2024080837 A1 WO2024080837 A1 WO 2024080837A1 KR 2023015867 W KR2023015867 W KR 2023015867W WO 2024080837 A1 WO2024080837 A1 WO 2024080837A1
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WO
WIPO (PCT)
Prior art keywords
electrode assembly
secondary battery
electrolyte
pouch
battery
Prior art date
Application number
PCT/KR2023/015867
Other languages
French (fr)
Korean (ko)
Inventor
김현진
위연화
김창호
김선욱
김재민
Original Assignee
주식회사 엘지에너지솔루션
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Application filed by 주식회사 엘지에너지솔루션 filed Critical 주식회사 엘지에너지솔루션
Priority claimed from KR1020230136858A external-priority patent/KR20240052696A/en
Publication of WO2024080837A1 publication Critical patent/WO2024080837A1/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
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • 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
    • H01M50/116—Primary casings; Jackets or wrappings characterised by the material
    • H01M50/124—Primary casings; Jackets or wrappings characterised by the material having a layered structure
    • H01M50/126—Primary casings; Jackets or wrappings characterised by the material having a layered structure comprising three or more layers
    • 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
    • H01M50/14—Primary casings; Jackets or wrappings for protecting against damage caused by external factors
    • H01M50/141—Primary casings; Jackets or wrappings 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
    • H01M50/60—Arrangements or processes for filling or topping-up with liquids; Arrangements or processes for draining liquids from casings
    • H01M50/673—Containers for storing liquids; Delivery conduits therefor
    • H01M50/682—Containers for storing liquids; Delivery conduits therefor accommodated in battery or cell casings

Definitions

  • the present invention relates to secondary batteries, and more specifically, to secondary batteries with excellent impact resistance.
  • Secondary batteries generally manufacture positive electrodes and negative electrodes by applying electrode active material slurry to the positive electrode current collector and negative electrode current collector, and then stack them on both sides of a separator to form an electrode assembly of a predetermined shape. , It is manufactured by storing the electrode assembly in a pouch and injecting electrolyte.
  • the pouch-type secondary battery is manufactured by performing press processing on a flexible pouch film laminate to form a cup portion, storing the electrode assembly in the cup portion, injecting electrolyte solution, and sealing the sealing portion, and can-type ( Can Type) Secondary batteries are manufactured by placing an electrode assembly in a can made of metal, injecting an electrolyte solution, and then assembling a top cap on the top of the can to seal it.
  • Pouch-type secondary batteries have the advantage of being light in weight, excellent in space utilization, and capable of realizing high energy density using a stacked electrode assembly, but have the problem of being vulnerable to external shock compared to can-type secondary batteries.
  • the present invention is intended to solve the above problems.
  • the size of the electrode assembly and the amount of electrolyte per unit capacity satisfy certain conditions, thereby increasing the friction between the electrode assembly and the battery case (e.g., pouch). It relates to a secondary battery in which separation of the electrode assembly and/or leakage of electrolyte is suppressed even when subjected to external shock or mechanical stress.
  • the present invention provides a secondary battery that includes a battery case including an electrode assembly, an electrolyte, and a receiving portion for accommodating the electrode assembly and the electrolyte, and satisfies the following equation (1).
  • Equation (1) W/S ⁇ 42
  • W is the electrolyte weight per unit capacity of the secondary battery [unit: g/Ah]
  • S is the product of the overall length [unit: m] and the overall width [unit: m] of the electrode assembly. .
  • the secondary battery disclosed herein may include any, part, or all of the features described further below.
  • the secondary battery may be a pouch-shaped battery, a cylindrical battery, a prismatic battery, etc.
  • the secondary battery may be a pouch-shaped battery.
  • the capacity of the secondary battery means the rated capacity of the secondary battery.
  • the secondary battery may have a rated capacity of 50 Ah to 200 Ah, preferably 50 Ah to 150 Ah, and more preferably 60 Ah to 140 Ah.
  • “Rated capacity of secondary battery” refers to the electric capacity developed when a fully charged battery is continuously discharged at 0.33C and reaches the discharge end voltage. At this time, the full charge voltage (charge end voltage) and discharge end voltage may be appropriately selected depending on the type of secondary battery. For example, when the secondary battery is an NCM cell, the rated capacity may be the discharge capacity when the secondary battery is charged to 4.25V and then discharged to 2.5V at 0.33C.
  • “Unit capacity” means 1 Ah.
  • the W may have a unit of g/Ah
  • the S may have a unit of m 2
  • the W/S may have a unit of (g/Ah) ⁇ m -2 .
  • the W may be 2.2 g/Ah or less, preferably 1.5 to 2.2 g/Ah, and more preferably 1.7 to 2.2 g/Ah, and the S may be 0.01 m 2 to 0.2 m 2 , 0.02 m 2 to 0.09 m 2 , preferably 0.03m 2 to 0.08m 2 , more preferably 0.03m 2 to 0.75m 2 .
  • the weight of the electrolyte in the secondary battery refers to the amount of electrolyte remaining in the secondary battery after the activation process. Accordingly, the total weight of the electrolyte may refer to the total weight of the electrolyte present after completion of manufacturing or during operation of the secondary battery.
  • the W/S (unit: (g/Ah) ⁇ m -2 ) is, for example, 0.1 (g/Ah) ⁇ m -2 to 42 (g/Ah) ⁇ m -2 , 1 (g/Ah) ) ⁇ m -2 to 42(g/Ah) ⁇ m -2 , 5(g/Ah) ⁇ m -2 to 42(g/Ah) ⁇ m -2 , 10(g/Ah) ⁇ m -2 to It may be 42(g/Ah) ⁇ m -2 , or 20(g/Ah) ⁇ m -2 to 42(g/Ah) ⁇ m -2 , but is not limited thereto.
  • the W/S (unit: (g/Ah) ⁇ m -2 ) is 30 (g/Ah) ⁇ m -2 to 42 (g/Ah) ⁇ m -2 , more preferably 35 (g /Ah) ⁇ m -2 to 42(g/Ah) ⁇ m -2 .
  • the secondary battery prepares an electrode active material slurry, applies it to a positive electrode current collector and a negative electrode current collector to obtain a positive electrode and a negative electrode, and attaches at least one layer of the positive electrode and at least one layer of the separator between the positive electrode layer and the negative electrode layer. It can be manufactured by stacking the electrode assembly with a separator interposed therebetween, storing the electrode assembly in a battery case such as a pouch, cylindrical can, or square can, and then adding an electrolyte to the electrode assembly.
  • the pouch-type secondary battery presses the pouch film laminate to form a cup with a shape and dimension to accommodate the electrode assembly, then places the electrode assembly in the cup, adds an electrolyte, and then stacks the pouch film. It can be manufactured by sealing along the sealing part of the sieve.
  • a can-type secondary battery can be manufactured by placing an electrode assembly in a metal can, injecting an electrolyte into the can, and sealing the can by mounting a cap on the opening of the can.
  • the can may have a cylindrical or angular shape, such as a rectangle, a cuboid, or a diamond.
  • the electrolyte of the secondary battery will be described later.
  • the electrode assembly of the secondary battery will be described later.
  • the battery case of a secondary battery may be a pouch, and the pouch may be used as a commonly understood concept in the field of secondary battery design and manufacturing.
  • the battery case of the secondary battery may be a can as described herein. At least a portion of the electrolyte may be provided between the electrode assembly and the inner surface of the battery case facing the electrode assembly.
  • the electrode assembly may have a rectangular shape extending in the longitudinal direction on a plane.
  • overall length means the length measured in the longitudinal direction, unless otherwise specified.
  • the width direction of the electrode assembly represents a direction perpendicular to the longitudinal direction, and is disposed on the plane of at least one layer of the anode, cathode, and separator.
  • the full width is a value measured in the width direction unless otherwise specified.
  • the anode layers, cathode layers, and separator may be stacked in a thickness direction perpendicular to both the longitudinal and width directions.
  • flatness may mean a gaze direction parallel to the thickness direction of the electrode assembly.
  • the electrode assembly may be wound along a winding axis parallel to the longitudinal or width direction. Therefore, the other direction of the longitudinal direction and the width direction that is not parallel to the winding axis may be parallel to the circumferential direction of the electrode assembly.
  • the overall length refers to the length of the electrode assembly in the direction of the winding axis in the wound state
  • the overall width refers to the length of the electrode assembly in the direction perpendicular to the winding axis in the wound state.
  • the battery case may be a pouch that can be provided in any manner disclosed herein.
  • the pouch may be formed by pressing at least one cup portion onto a pouch film laminate.
  • the cup portion may be formed as a flat portion protruding outward from the remaining portion of the pouch film laminate.
  • the cup portion may have a tray-like shape.
  • the cup portion may include a flat main surface surrounded by one or more side walls that are integral with the remainder of the pouch film stack.
  • the flat main surface of the cup portion may have a basic shape of a flat rectangle, but the corners may be rounded depending on processing requirements or design.
  • the pouch may have any, some, or all of the features of the pouch described herein, unless otherwise specified or technically inappropriate.
  • the battery case may be a pouch made of a pouch film laminate.
  • the pouch specifically, the pouch film laminate, may include a barrier layer, a base layer, and a sealant layer.
  • the base layer may be disposed on one side of the barrier layer, and the sealant layer may be disposed on the other side of the barrier layer (i.e., the opposite side of the base layer).
  • the base layer, the barrier layer, and the sealant layer may form a pouch film laminate, specifically, a laminated structure.
  • the pouch, specifically the pouch film laminate is press molded (specifically, stretch molded and/or or drawing).
  • the electrode assembly may be accommodated in the one or more cup portions.
  • the at least one cup portion may have a shape and dimension to accommodate the electrode assembly.
  • Components of the pouch may implement any, part, or all of the features disclosed herein, unless otherwise specified or technically inappropriate. Specifically, any one of the base layer, barrier layer, and sealant layer may be implemented as each is described in detail below.
  • the secondary battery may have a rated capacity of 50 Ah to 200 Ah, preferably 50 Ah to 150 Ah, and more preferably 60 Ah to 140 Ah.
  • the electrode assembly may have a substantially rectangular shape in a plane, and a ratio of the overall length to the overall width of the electrode assembly may be 2.5 to 20, 3 to 15, 5 to 10, or 5 to 8.
  • a ratio of the overall length to the overall width of the electrode assembly satisfies the above specific range, it can further contribute to increasing friction without increasing the amount of electrolyte.
  • the electrode assembly may have a total length of 200 mm to 800 mm and an overall width of 40 mm to 200 mm.
  • the electrode assembly may have a total length of 400 mm to 600 mm and an overall width of 50 to 150 mm, and more preferably, the overall length may be 500 mm to 600 mm and an overall width of 50 to 100 mm.
  • the full length and full width may mean the maximum extended length of the electrode assembly in the longitudinal and width directions on a plane, respectively.
  • the weight of the electrode assembly may be 500g to 1500g, preferably 550g to 1450g, and more preferably 600g to 1400g.
  • the weight of the electrode assembly satisfies the above range, high capacity can be realized, and the friction between the electrode assembly and the inner surface of the battery case increases, resulting in excellent impact resistance.
  • the secondary battery according to the present invention may further include at least one fixing member fixed to the outer surface of the electrode assembly by wrapping the electrode assembly in the full width direction.
  • the contact area between the fixing member and the electrode assembly This may be 30% or less, 0 to 30%, 1 to 30%, 5 to 30%, 5 to 25%, or 5 to 20% of the total surface area of the electrode assembly.
  • the fixing member is generally made of a material with a low coefficient of friction, when the area of the fixing member increases, the friction between the electrode assembly and the inner surface of the battery case may decrease. Therefore, when using a fixing member, it is desirable to suppress a decrease in friction force by setting the contact area between electrode assemblies to 30% or less.
  • the battery case may be a pouch-type case, and the pouch-type case includes a barrier layer, a base layer formed on one side of the barrier layer, and a sealant layer formed on the other side of the barrier layer, and is oriented in one direction. It may be a pouch including at least one curved cup portion, and an electrode assembly and an electrolyte may be accommodated in the cup portion of the pouch.
  • the friction force between the electrode assembly and the inner surface of the battery case may be 15 kgf or more, preferably 15 kgf to 40 kgf, and more preferably 17 kgf to 35 kgf.
  • the friction force between the electrode assembly and the inner surface of the battery case can be measured as follows. Cut a part of the battery case, hold the positive tab with a jig with a wire connected to it, connect the wire to a universal testing machine (UTM), and pull it at a constant speed, for example, 100 mm/min, and measure the force ( Force) can be measured and evaluated as the friction between the electrode assembly and the inner surface of the battery case.
  • UPM universal testing machine
  • the electrode assembly may have an overall length of 0.2 m to 0.8 m, an overall width of 0.05 m to 0.15 m, and an electrolyte weight per unit capacity of 1.0 to 2.8 g/Ah.
  • W/S may be 30 (g/Ah) ⁇ m-2 to 42 (g/Ah) ⁇ m-2.
  • the electrode assembly may have an overall length of 0.3 m to 0.8 m, an overall width of 0.06 m to 0.12 m, and an electrolyte weight per unit capacity of 1.2 to 2.5 g/Ah. In this case, W/S may be 30 (g/Ah) ⁇ m-2 to 42 (g/Ah) ⁇ m-2.
  • the electrode assembly may have an overall length of 0.4 m to 0.6 m, an overall width of 0.07 m to 0.11 m, and an electrolyte weight per unit capacity of 1.5 to 2.4 g/Ah.
  • W/S may be 30 (g/Ah) ⁇ m-2 to 42 (g/Ah) ⁇ m-2.
  • the present invention can provide a secondary battery including an electrode assembly, an electrolyte, and a battery case.
  • the electrode assembly may have a surface area of 0.01 to 0.2 m 2 , and the total weight of the electrolyte may be 440 g or less.
  • the battery case can accommodate an electrode assembly and an electrolyte.
  • the electrode assembly, electrolyte, and battery case may be configured such that the frictional force between the electrode assembly and the inner surface of the battery case is 15 kgf or more.
  • the surface area of the electrode assembly may be the product of the full length and the full width.
  • the surface area of the electrode assembly may be 0.02 m 2 to 0.08 m 2 , or 0.03 m 2 to 0.07 m 2 or 0.04 m 2 to 0.06 m 2 .
  • the friction between the electrode assembly and the battery case increases significantly compared to the prior art, and this causes the electrode assembly to break away in the event of an external impact. And/or electrolyte leakage can be suppressed to achieve excellent impact resistance.
  • FIG. 1 is an exploded perspective view of a secondary battery according to an embodiment of the present invention.
  • Figure 2 is a diagram for explaining the configuration of a pouch according to one embodiment.
  • electrolyte remaining after impregnating the electrode assembly may remain on the surface of the electrode assembly and the inner surface of the battery case. Since the electrolyte has wet characteristics, if electrolyte is present on the inner surface of the battery case and the surface of the electrode assembly, the electrode assembly and the battery The friction between the inner surfaces of the case is reduced, which further increases the flow of the electrode assembly upon external impact. When the total amount of electrolyte in the secondary battery increases, the amount of electrolyte remaining inside the electrode assembly and the battery case increases, which further reduces friction. Therefore, in terms of impact resistance, the smaller the amount of electrolyte in the secondary battery, the better. However, if the amount of electrolyte is too small, the capacity of the secondary battery may be adversely affected and the operability and lifespan of the secondary battery may be reduced.
  • the present inventors have conducted repeated research to develop a secondary battery that can achieve excellent both electrochemical performance and impact resistance of the battery.
  • the electrode assembly It was found that the friction between the battery case and the battery case is greatly increased compared to the prior art, and as a result, damage to the battery case due to separation of the electrode assembly during external impact is suppressed, making it possible to minimize the degradation of electrochemical properties while realizing excellent impact resistance.
  • the present invention has been completed.
  • the secondary battery according to the present invention includes a battery case including an electrode assembly, an electrolyte, and a receiving portion for accommodating the electrode assembly and the electrolyte, and is characterized by satisfying the following equation (1).
  • Equation (1) W/S ⁇ 42
  • the unit of W/S in equation (1) above is (g/Ah) ⁇ m-2.
  • the W (unit: g/Ah) is the weight of electrolyte per unit capacity of the secondary battery, and can be measured by dividing the total weight of electrolyte in the secondary battery (unit: g) by the rated capacity of the secondary battery (unit: Ah). Meanwhile, the total weight of the electrolyte in the secondary battery refers to the total weight of the electrolyte remaining in the secondary battery after the activation process.
  • the W/S (unit: (g/Ah) ⁇ m -2 ) is 42 (g/Ah) ⁇ m -2 or less, 0.1 (g/Ah) ⁇ m -2 to 42 (g/Ah) ) ⁇ m -2 , 1(g/Ah) ⁇ m -2 to 42(g/Ah) ⁇ m -2 , 5(g/Ah) ⁇ m -2 to 42(g/Ah) ⁇ m -2 , It may be 10(g/Ah) ⁇ m -2 to 42(g/Ah) ⁇ m -2 , or 20(g/Ah) ⁇ m -2 to 42(g/Ah) ⁇ m -2 , but is limited thereto. It doesn't work.
  • the W/S (unit: (g/Ah) ⁇ m -2 ) is 30 (g/Ah) ⁇ m -2 to 42 (g/Ah) ⁇ m -2 , more preferably 35 (g /Ah) ⁇ m -2 to 42(g/Ah) ⁇ m -2 .
  • W/S is 42(g/Ah) ⁇ m -2 or less, the friction between the electrode assembly and the inner surface of the battery case (for example, the bottom surface of the cup of the pouch) in contact with the electrode assembly greatly increases, resulting in When external shock is applied, separation of the electrode assembly is minimized, thereby minimizing electrolyte leakage due to damage to the battery case.
  • the W may vary depending on the size of the electrode assembly, but for example, 2.2 g/Ah or less, preferably 1.5 g/Ah to 2.2 g/Ah, more preferably 1.7 g/Ah to 2.2 g. It could be /Ah. If W is too large, the effect of increasing friction between the electrode assembly and the inner surface of the battery case is minimal, and if W is too small, battery performance may deteriorate due to insufficient electrolyte during battery operation.
  • S is the cross-sectional area of the electrode assembly, which is a value obtained by multiplying the full length and full width of the electrode assembly.
  • the full length and full width are measured in m units.
  • the S may be, for example, 0.02 to 0.09 m 2 , preferably 0.03 to 0.08 m 2 , and more preferably 0.03 to 0.75 m 2 . If S is too small, the battery capacity decreases and the effect of increasing friction between the electrode assembly and the battery case is minimal, and if S is too large, there is a greater risk of accidents when a stability issue occurs.
  • the secondary battery may have a rated capacity of 50 Ah to 200 Ah, preferably 50 Ah to 150 Ah, and more preferably 60 Ah to 140 Ah. When the rated capacity of the secondary battery satisfies the above range, a high capacity secondary battery can be implemented.
  • the secondary battery according to the present invention may be a pouch-type secondary battery.
  • the battery case includes, for example, a barrier layer, a base layer formed on one side of the barrier layer, and a sealant layer formed on the other side of the barrier layer, and at least one cup portion indented in one direction. It may be a pouch containing an electrode assembly and an electrolyte in the cup portion of the pouch.
  • the friction force between the electrode assembly and the inner surface of the battery case is 15 kgf or more, preferably 15 kgf to 40 kgf, more preferably It is high at 17kgf to 35kgf, which minimizes damage to the pouch as there is little separation of the electrode assembly due to external impact, and this results in excellent impact resistance.
  • the friction force between the electrode assembly and the inner surface of the battery case can be measured by the following method.
  • the secondary battery according to the present invention has high friction between the electrode assembly and the battery case, minimizing separation of the electrode assembly during external impact, and thus has excellent impact resistance.
  • electrolyte leakage does not occur when a crash shock test is performed under a crash condition of 133.7G ⁇ 15.8ms. That is, the secondary battery according to the present invention has an electrolyte leakage amount of 0 after a crash shock test under a crash condition of 133.7G ⁇ 15.8ms.
  • the crash shock test can be performed by mounting the battery to be measured on a jig of drop shock equipment, letting the battery fall freely from a certain height, and then determining whether the battery is damaged.
  • the free fall height is set in consideration of the collision condition (acceleration ⁇ duration time) to be measured.
  • the impact energy in the collision condition to be measured can be converted into potential energy, and then the free fall height can be set by calculating the height that can have the converted potential energy by considering the weight of the battery to be measured. Meanwhile, damage to the battery can be evaluated by whether electrolyte leaks or not.
  • FIG. 1 is an exploded perspective view of a pouch-type secondary battery, which is an example of a secondary battery according to the present invention
  • FIG. 2 is a cross-sectional view of a pouch film laminate.
  • the pouch 100 is a battery case for accommodating an electrode assembly and an electrolyte, and includes a barrier layer 20, a base layer 10 formed on one side of the barrier layer, and a sealant layer 30 formed on the other side of the barrier layer. ) and includes at least one cup portion (receiving portion) indented in one direction.
  • the pouch 100 has flexibility, and a pouch film laminate in which a base layer 10, a barrier layer 20, and a sealant layer 30 are sequentially laminated is inserted into a press molding device, and the pouch is formed. It can be manufactured by applying pressure to a portion of the film laminate with a punch and stretching it to form a cup portion that is indented in one direction.
  • the base layer 10 is disposed on the outermost layer of the pouch to protect the electrode assembly from external shock and electrically insulate it.
  • the base layer 10 may be made of a polymer material, for example, polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, polyvinyl chloride, acrylic polymer, polyacrylonitrile, polyimide, polyamide, cellulose. , aramid, nylon, polyester, polyparaphenylenebenzobisoxazole, polyarylate, and Teflon.
  • a polymer material for example, polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, polyvinyl chloride, acrylic polymer, polyacrylonitrile, polyimide, polyamide, cellulose. , aramid, nylon, polyester, polyparaphenylenebenzobisoxazole, polyarylate, and Teflon.
  • the base layer 10 may have a single-layer structure or a multi-layer structure in which different polymer films 12 and 14 are stacked, as shown in FIG. 2 .
  • an adhesive layer 16a may be interposed between the polymer films.
  • the base layer 10 may have a total thickness of 10 ⁇ m to 60 ⁇ m, preferably 20 ⁇ m to 50 ⁇ m, and more preferably 30 ⁇ m to 50 ⁇ m.
  • the thickness includes the adhesive layer.
  • durability, insulation, and moldability are excellent. If the thickness of the base layer is too thin, durability decreases and damage to the base layer may occur during the molding process. If it is too thick, moldability may decrease, the overall thickness of the pouch increases, and the battery storage space decreases, lowering the energy density. may deteriorate.
  • the base layer 10 may have a laminated structure of a polyethylene terephthalate (PET) film and a nylon film.
  • PET polyethylene terephthalate
  • nylon film is disposed on the barrier layer 20 side, that is, on the inside, and the polyethylene terephthalate film is disposed on the surface side of the pouch.
  • PET Polyethylene terephthalate
  • the adhesiveness with the aluminum alloy thin film constituting the barrier layer 20 is weak and the stretching behavior is also different. Therefore, when the PET film is placed on the barrier layer side, the base layer and the barrier layer are separated during the molding process. Peeling may occur, and the barrier layer may not be stretched uniformly, which may cause problems with reduced formability.
  • the nylon film since the nylon film has similar stretching behavior to the aluminum alloy thin film constituting the barrier layer 20, the formability improvement effect can be obtained when the nylon film is placed between polyethylene terephthalate and the barrier layer.
  • the polyethylene terephthalate film may have a thickness of 5 ⁇ m to 20 ⁇ m, preferably 5 ⁇ m to 15 ⁇ m, more preferably 7 ⁇ m to 15 ⁇ m, and the nylon film may have a thickness of 2010 ⁇ m to 40 ⁇ m, Preferably it may be 2010 ⁇ m to 35 ⁇ m, more preferably 2515 ⁇ m to 25 ⁇ m.
  • the thickness of the polyethylene terephthalate film and the nylon film satisfies the above range, excellent moldability and rigidity after molding are exhibited.
  • the barrier layer 20 is used to secure the mechanical strength of the pouch 100, block gas or moisture from entering the secondary battery, and prevent electrolyte leakage.
  • the barrier layer 20 may have a thickness of 40 ⁇ m to 100 ⁇ m, more preferably 50 ⁇ m to 80 ⁇ m, and more preferably 60 ⁇ m to 80 ⁇ m.
  • the barrier layer thickness satisfies the above range, formability is improved and the molding depth of the cup portion is increased or cracks and/or pinholes are less likely to occur even when molding two cups, thereby improving resistance to external stress after molding.
  • the barrier layer 20 may be made of a metal material, and specifically, may be made of an aluminum alloy thin film.
  • the aluminum alloy thin film includes aluminum and metal elements other than aluminum, such as iron (Fe), copper (Cu), chromium (Cr), manganese (Mn), nickel (Ni), magnesium (Mg), and silicon. It may include one or two or more types selected from the group consisting of (Si) and zinc (Zn).
  • metal elements other than aluminum such as iron (Fe), copper (Cu), chromium (Cr), manganese (Mn), nickel (Ni), magnesium (Mg), and silicon. It may include one or two or more types selected from the group consisting of (Si) and zinc (Zn).
  • the aluminum alloy thin film may have an iron (Fe) content of 1.2 wt% to 1.7 wt%, preferably 1.3 wt% to 1.7 wt%, and more preferably 1.3 wt% to 1.45 wt%.
  • Fe iron
  • the iron (Fe) content in the aluminum alloy thin film satisfies the above range, the occurrence of cracks or pinholes can be minimized even when the cup portion is formed deeply.
  • the sealant layer 30 is bonded through heat compression to seal the pouch, and is located in the innermost layer of the pouch film laminate 1.
  • sealant layer 30 is the surface that comes into contact with the electrolyte and electrode assembly after the pouch is molded, it must have insulation and corrosion resistance. It must completely seal the interior to block material movement between the inside and the outside, so it must have high sealing properties. .
  • the sealant layer 30 may be made of a polymer material, for example, polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, polyvinyl chloride, acrylic polymer, polyacrylonitrile, polyimide, polyamide, It may be made of one or more selected from the group consisting of cellulose, aramid, nylon, polyester, polyparaphenylenebenzobisoxazole, polyarylate, and Teflon, among which tensile strength, rigidity, surface hardness, abrasion resistance, and heat resistance. It is particularly preferable to include polypropylene (PP), which has excellent mechanical properties and chemical properties such as corrosion resistance.
  • PP polypropylene
  • the sealant layer 30 is polypropylene, cast polypropylene (CPP), acid modified polypropylene, polypropylene-butylene-ethylene copolymer, or a combination thereof. It may include.
  • the sealant layer 30 may have a single-layer structure or a multi-layer structure including two or more layers made of different polymer materials.
  • the sealant layer may have a total thickness of 60 ⁇ m to 100 ⁇ m, preferably 60 ⁇ m to 90 ⁇ m, more preferably 70 ⁇ m to 90 ⁇ m. If the thickness of the sealant layer is too thin, sealing durability and insulation may be reduced, and if it is too thick, flexibility may decrease and the total thickness of the pouch film laminate may increase, resulting in a decrease in energy density relative to volume.
  • the pouch film laminate 1 can be manufactured through a pouch film laminate manufacturing method known in the art.
  • the base layer 10 is attached to the upper surface of the barrier layer 20 through an adhesive
  • the sealant layer 30 is attached to the lower surface of the barrier layer 20 through coextrusion or adhesive. It can be manufactured through a forming method, but is not limited to this.
  • the pouch 100 is manufactured by inserting the pouch film laminate as described above into a molding device and applying pressure to a portion of the pouch film laminate with a punch to form a cup portion.
  • the pressure may be 0.3 MPa to 1 MPa, preferably 0.3 MPa to 0.8 MPa, and more preferably 0.4 MPa to 0.6 MPa. If the pressure is too low when molding the cup portion, excessive drawing may occur and wrinkles may occur, and if it is too high, drawing may not occur well and the molding depth may be reduced.
  • the moving speed of the punch may be 20 mm/min to 80 mm/min, preferably 30 mm/min to 70 mm/min, and more preferably 40 mm/min to 60 mm/min. If the pressure during molding is too small or the moving speed of the punch is too fast, wrinkles may occur due to buckling. If the pressure during molding is too large or the moving speed of the punch is too slow, cup corners may appear during molding. As the stress concentrated in increases, the occurrence of pinholes or cracks may increase.
  • the pouch 100 of the present invention manufactured through the method described above includes a lower case 101, an upper case 102, and a folding portion 130 connecting the lower case and the lower case.
  • the lower case includes a cup portion 110 that is indented in one direction.
  • the pouch 100 may have a 1-cup shape with the cup portion 110 formed only in the lower case 101, but is not limited thereto, and includes the upper case and It may be a two-cup type with cup portions formed on both lower cases.
  • the upper case is folded so that the cup portion of the upper case and the cup portion of the lower case face each other, so it can accommodate a thicker electrode assembly than a 1-cup pouch. This has the advantage of being advantageous in realizing high energy density.
  • the cup portion 110 has a receiving space for accommodating the electrode assembly 200.
  • the pouch 100 may include a terrace 120 around the cup portion 110.
  • the terrace 120 refers to the unmolded portion of the pouch film laminate, that is, the remaining area excluding the cup portion 110.
  • the terrace 129 is a part that is sealed through thermal bonding in the process of accommodating the electrode assembly 200 in the cup portion 110, injecting electrolyte, and then sealing.
  • the cup portion 110 may include a bottom surface and a peripheral surface.
  • the peripheral surface may connect the floor surface and the terrace 120.
  • the bottom surface may cover one side of the electrode assembly 200, and the peripheral surface may surround the circumference of the electrode assembly 200.
  • the folding part 130 connects the lower case 101 and the upper case 102, stores the electrode assembly 200 in the cup part 110, and folds after injecting the electrolyte to form the upper case 102. It is possible to seal the cup portion 110 of the lower case 101.
  • the folding part 130 is included, the lower case 101 and the upper case 102 are integrally connected, so when performing a sealing process later, the number of sides to be sealed is reduced, thereby improving fairness.
  • the folding part 130 is formed to be spaced apart from the cup part 110, and the separation distance between the folding part 130 and the cup part 110 may be about 0.5 mm to 3 mm, preferably about 0.5 mm to 2 mm. If the folding part 130 is formed too close to the cup part 110, folding is not performed smoothly, and if the folding part 130 is formed too far from the cup part 110, the total volume of the secondary battery increases and the energy density relative to volume increases. may decrease. In the case of a 2-cup case, the folding portion may be formed to satisfy the above-mentioned separation distance for each cup portion.
  • the electrode assembly 200 may include a plurality of electrodes and a plurality of separators that are alternately stacked.
  • the plurality of electrodes are alternately stacked with a separator in between and may include an anode and a cathode having opposite polarities.
  • the electrode assembly 200 may be provided with a plurality of electrode tabs 230 welded to each other.
  • the plurality of electrode tabs 230 may be connected to the plurality of electrodes 210 and may protrude outward from the electrode assembly 200 to act as a path through which electrons can move between the inside and outside of the electrode assembly 200. there is.
  • a plurality of electrode tabs 230 may be located inside the pouch 100.
  • the electrode tab 230 connected to the anode and the electrode tab 230 connected to the cathode may protrude in different directions with respect to the electrode assembly 200. However, it is not limited to this, and it is possible for the electrode tab 230 connected to the anode and the electrode tab 230 connected to the cathode to protrude in the same direction and parallel to each other.
  • Leads 240 that supply electricity to the outside of the secondary battery may be connected to the plurality of electrode tabs 230 by spot welding or the like. One end of the lead 240 may be connected to the plurality of electrode tabs 230 and the other end may protrude to the outside of the pouch 100 .
  • a portion of the lead 240 may be surrounded by an insulating portion 250 .
  • the insulating portion 250 may include an insulating tape.
  • the insulating portion 250 may be located between the terrace 120 of the first case 101 and the second case 102, and in this state, the terrace 120 and the second case 102 are opened to each other. can be fused.
  • a portion of the terrace 120 and the second case 102 may be heat-sealed to the insulating portion 250. Accordingly, the insulating portion 250 prevents electricity generated from the electrode assembly 200 from flowing into the pouch 100 through the lead 240 and maintains the seal of the pouch 100.
  • the electrode assembly 200 may have a ratio of the full length to the full width length of 5 to 10, preferably 5 to 8.
  • the ratio of total length to total width satisfies the above range, high energy density can be achieved in a limited space.
  • the electrode assembly may have an overall length of 400 mm to 600 mm and an overall width of 50 to 150 mm, preferably 500 mm to 600 mm in overall length, and 50 to 100 mm in overall width.
  • the weight of the electrode assembly may be 500 g to 1500 g, preferably 550 g to 1450 g, and more preferably 600 g to 1400 g.
  • the weight of the electrode assembly satisfies the above range, high capacity can be realized, and the friction between the electrode assembly and the inner surface of the battery case increases, resulting in excellent impact resistance.
  • the secondary battery according to the present invention may further include at least one fixing member on the outer surface of the electrode assembly, if necessary.
  • the electrode assembly is used to prevent the alignment of the components of the electrode assembly, that is, the anode, cathode, and separator, from being disturbed.
  • a fixing member that secures the assembly by wrapping it in the full width direction can be used.
  • the fixing member may include a porous structure.
  • the electrolyte can pass through the fixing member and be impregnated into the electrode assembly, thereby preventing the electrolyte impregnation of the electrode assembly from being deteriorated due to the fixing member.
  • the fixing member may be a finishing tape with an adhesive layer formed on one side of a polymer base layer having a porous structure, but is not limited thereto.
  • the polymer material may be, for example, polyethylene terephthalate (PET), polyvinyl chloride (PVC), polyethylene (PE), etc., but is not limited thereto.
  • the fixing member preferably has a width of about 10 to 50 mm or 20 to 40 mm along the full width direction of the electrode assembly. If the width of the fixing member is too wide, the outer surface area of the electrode assembly covered by the fixing member increases and the contact area with the electrolyte decreases, which may reduce electrolyte impregnation and reduce the friction between the electrode assembly and the battery case. Impact resistance may decrease. On the other hand, if the width of the fixing member is too thin, the effect of fixing the electrode assembly may be reduced.
  • the secondary battery may include 2 to 10 fixing members, preferably 2 to 8 fixing members, and more preferably 3 to 7 fixing members.
  • the fixing members may be arranged in left and right symmetrical positions along the overall length direction, and preferably, the fixing members may be spaced apart at equal intervals.
  • the contact area between the fixing member and the electrode assembly may be 30% or less, 25% or less, or 20% or less of the total surface area of the electrode assembly.
  • the contact area between the fixing member and the electrode assembly may be 0 to 30%, 1 to 30%, 5 to 30%, 5 to 25%, or 5 to 20% of the total surface area of the electrode assembly. .
  • the contact area between the fixing member and the electrode assembly can be adjusted by adjusting the width of the fixing member used or the number of fixing members used. Since the commonly used fixing member is made of a material with a lower friction coefficient than the separator disposed on the outermost surface of the electrode assembly, if the area of the fixing member surrounding the electrode assembly increases, the friction between the electrode assembly and the inner surface of the battery case will decrease. You can. Therefore, when using a fixing member, it is desirable to suppress a decrease in friction force by setting the contact area between electrode assemblies to 30% or less.
  • the electrolyte is used to move lithium ions generated by the electrochemical reaction of the electrode during charging and discharging of the secondary battery, and may include an organic solvent and a lithium salt.
  • the organic solvent may be used without particular limitation as long as it can serve as a medium through which ions involved in the electrochemical reaction of the battery can move.
  • the organic solvent includes ester solvents such as methyl acetate, ethyl acetate, ⁇ -butyrolactone, and ⁇ -caprolactone; Ether-based solvents such as dibutyl ether or tetrahydrofuran; Ketone-based solvents such as cyclohexanone; Aromatic hydrocarbon solvents such as benzene and fluorobenzene; Dimethylcarbonate (DMC), diethylcarbonate (DEC), methylethylcarbonate (MEC), ethylmethylcarbonate (EMC), ethylene carbonate (EC), propylene carbonate Carbonate-based solvents such as PC); Alcohol-based solvents such as ethyl alcohol and isopropyl alcohol; nitriles such as R-CN (R is a C2 to C20 straight-chain, branched or
  • carbonate-based solvents are preferable, and cyclic carbonates (e.g., ethylene carbonate or propylene carbonate, etc.) with high ionic conductivity and high dielectric constant that can improve the charge/discharge performance of the battery, and low-viscosity linear carbonate-based compounds ( For example, ethylmethyl carbonate, dimethyl carbonate, diethyl carbonate, etc.) are more preferable.
  • cyclic carbonates e.g., ethylene carbonate or propylene carbonate, etc.
  • low-viscosity linear carbonate-based compounds For example, ethylmethyl carbonate, dimethyl carbonate, diethyl carbonate, etc.
  • the lithium salt can be used without particular limitations as long as it is a compound that can provide lithium ions used in lithium secondary batteries.
  • the lithium salt is LiPF 6 , LiClO 4 , LiAsF 6 , LiBF 4 , LiSbF 6 , LiAl0 4 , LiAlCl 4 , LiCF 3 SO 3 , LiC 4 F 9 SO 3 , LiN(C 2 F 5 SO 3 ) 2 , LiN(C 2 F 5 SO 2 ) 2 , LiN(CF 3 SO 2 ) 2 .
  • LiCl, LiI, or LiB(C 2 O 4 ) 2 may be used.
  • the concentration of the lithium salt is preferably used within the range of 0.1 to 5.0M, preferably 0.1 to 3.0M. When the concentration of lithium salt is within the above range, the electrolyte has appropriate conductivity and viscosity, so excellent electrolyte performance can be achieved and lithium ions can move effectively.
  • the electrolyte may further include additives for the purpose of improving battery life characteristics, suppressing battery capacity reduction, and improving battery discharge capacity.
  • a pouch in which nylon/polyethylene terephthalate/Al alloy thin film/polypropylene were sequentially laminated and the cup portion was molded was prepared. After storing the stacked electrode assembly with a total length of 548 mm, a total width of 99 mm, and a weight of 1380 g in the cup part, an electrolyte solution was injected, sealing was performed, and an activation process was performed to manufacture a pouch-type secondary battery. At this time, the electrolyte was injected so that the amount of remaining electrolyte per unit capacity was 2.2 g/Ah after the activation process.
  • a pouch-type secondary battery was manufactured in the same manner as Example 1, except that the electrolyte was injected so that the amount of remaining electrolyte per unit capacity was 2.15 g/Ah after the activation process.
  • a stacked electrode assembly with a total length of 548 mm, a total width of 78 mm, and a weight of 641 g was used, and the same method as Example 1 was used, except that the electrolyte solution was injected so that the amount of remaining electrolyte per unit capacity was 1.7 g/Ah after the activation process.
  • a pouch-type secondary battery was manufactured.
  • a stacked electrode assembly with a total length of 548 mm, a total width of 78 mm, and a weight of 641 g was used, and the same method as Example 1 was used, except that the electrolyte solution was injected so that the amount of remaining electrolyte per unit capacity was 2.2 g / Ah after the activation process.
  • a pouch-type secondary battery was manufactured.
  • a pouch-type secondary battery was manufactured in the same manner as Example 1, except that the electrolyte was injected so that the amount of remaining electrolyte per unit capacity was 2.3 g/Ah after the activation process.
  • a crash shock test was performed on the pouch-type secondary batteries manufactured in Examples 1 to 3 and Comparative Examples 1 to 2 under crash conditions of 133.7G x 15.8ms. The measurement results are shown in Table 1 below. If electrolyte leakage and electrode assembly separation did not occur after the test, it was marked as Pass, and if electrolyte leakage and/or electrode assembly separation occurred, it was marked as Fail.

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Abstract

The present invention relates to a secondary battery with excellent impact resistance. The secondary battery according to the present invention comprises an electrode assembly, an electrolyte, and a battery case including an accommodation unit for accommodating the electrode assembly and the electrolyte, and satisfies formula (1). In formula (1): W / S ≤ 42(g/Ah)·m-², W is an electrolyte amount [unit: g/Ah] per unit capacity of the secondary battery, and S is a multiplication of the full length [unit: m] and the full width [unit: m] of the electrode assembly.

Description

이차 전지secondary battery
본 발명은 이차 전지에 관한 것으로, 보다 상세하게는 내충격성이 우수한 이차 전지에 관한 것이다. The present invention relates to secondary batteries, and more specifically, to secondary batteries with excellent impact resistance.
이차 전지는 일반적으로 전극 활물질 슬러리를 양극 집전체 및 음극 집전체에 도포하여 양극과 음극을 제조하고, 이를 분리막(Separator)의 양 측에 적층함으로써 소정 형상의 전극 조립체(Electrode Assembly)를 형성한 후, 파우치에 전극 조립체를 수납하고 전해액 주입하는 방식으로 제조된다. Secondary batteries generally manufacture positive electrodes and negative electrodes by applying electrode active material slurry to the positive electrode current collector and negative electrode current collector, and then stack them on both sides of a separator to form an electrode assembly of a predetermined shape. , It is manufactured by storing the electrode assembly in a pouch and injecting electrolyte.
이차 전지는 전극 조립체를 수용하는 케이스의 재질에 따라, 파우치 형(Pouch Type) 및 캔 형(Can Type) 등으로 분류된다. 이 중 파우치형 이차 전지는 유연성을 가지는 파우치 필름 적층체에 프레스 가공을 수행하여 컵부를 형성하고, 상기 컵부에 전극 조립체를 수납하여 전해액을 주입한 후 실링부를 실링하는 방식으로 제조되며, 캔 형(Can Type) 이차 전지는 금속 재질로 제조된 캔에 전극 조립체를 수용하고, 전해액을 주입한 후, 캔 상부에 탑캡을 조립하여 밀봉하는 방식으로 제조된다.Secondary batteries are classified into pouch type and can type, etc., depending on the material of the case that accommodates the electrode assembly. Among these, the pouch-type secondary battery is manufactured by performing press processing on a flexible pouch film laminate to form a cup portion, storing the electrode assembly in the cup portion, injecting electrolyte solution, and sealing the sealing portion, and can-type ( Can Type) Secondary batteries are manufactured by placing an electrode assembly in a can made of metal, injecting an electrolyte solution, and then assembling a top cap on the top of the can to seal it.
파우치형 이차 전지는 무게가 가볍고, 공간 활용성이 우수하며, 적층형 전극 조립체를 사용하여 높은 에너지 밀도를 구현할 수 있다는 장점이 있으나, 캔형 이차 전지에 비해 외부 충격에 취약하다는 문제점이 있다. Pouch-type secondary batteries have the advantage of being light in weight, excellent in space utilization, and capable of realizing high energy density using a stacked electrode assembly, but have the problem of being vulnerable to external shock compared to can-type secondary batteries.
최근 이차 전지의 사용 환경이 다양해짐에 따라 가혹한 환경에서도 우수한 내구성 및 안전성을 가질 것이 요구되고 있으며, 이에 따라 이차 전지의 내충격성 개선이 요구되고 있다. Recently, as the use environment of secondary batteries has become more diverse, there is a demand for excellent durability and safety even in harsh environments, and accordingly, there is a need to improve the impact resistance of secondary batteries.
본 발명은 상기와 같은 문제점을 해결하기 위한 것으로, 전극 조립체의 크기와 단위 용량 당 전해액 양이 특정 조건을 만족하여 전극 조립체와 전지 케이스(예를 들면, 파우치) 사이의 마찰력이 증가하고, 이로 인해 외부 충격이나 기계적 응력을 받더라도 전극 조립체의 이탈 및/또는 전해액 누설이 억제된 이차 전지에 관한 것이다. The present invention is intended to solve the above problems. The size of the electrode assembly and the amount of electrolyte per unit capacity satisfy certain conditions, thereby increasing the friction between the electrode assembly and the battery case (e.g., pouch). It relates to a secondary battery in which separation of the electrode assembly and/or leakage of electrolyte is suppressed even when subjected to external shock or mechanical stress.
일 구현예에 따르면, 본 발명은, 전극 조립체, 전해질 및 상기 전극 조립체 및 전해질을 수용하기 위한 수용부를 포함하는 전지 케이스를 포함하고, 하기 식 (1)을 만족하는 이차 전지를 제공한다. According to one embodiment, the present invention provides a secondary battery that includes a battery case including an electrode assembly, an electrolyte, and a receiving portion for accommodating the electrode assembly and the electrolyte, and satisfies the following equation (1).
식 (1): W / S ≤ 42Equation (1): W/S ≤ 42
상기 식 (1)에서, W는 상기 이차 전지의 단위 용량당 전해액 중량[단위: g/Ah]이며, 상기 S는 상기 전극 조립체의 전장[단위: m]와 전폭[단위: m]의 곱이다. In equation (1), W is the electrolyte weight per unit capacity of the secondary battery [unit: g/Ah], and S is the product of the overall length [unit: m] and the overall width [unit: m] of the electrode assembly. .
본 명세서에 개시된 이차 전지는 추가로 후술되는 특징 중 임의의 것, 일부 또는 전부를 포함할 수 있다. 상기 이차 전지는 파우치형 전지, 원통형 전지, 각형 전지 등일 수 있으며, 구체적인 예시에서, 상기 이차 전지는 파우치형 전지일 수 있다.The secondary battery disclosed herein may include any, part, or all of the features described further below. The secondary battery may be a pouch-shaped battery, a cylindrical battery, a prismatic battery, etc. In a specific example, the secondary battery may be a pouch-shaped battery.
다른 기재가 없다면, 이차 전지의 용량은 이차 전지의 정격 용량을 의미한다. 상기 이차 전지는 50Ah 내지 200Ah, 바람직하게는 50Ah 내지 150Ah, 더 바람직하게는 60Ah 내지 140Ah의 정격 용량을 가질 수 있다. “이차 전지의 정격 용량”은 만충전된 전지를 0.33C로 연속 방전시켜 방전 종지 전압까지 도달하였을 때 발현되는 전기 용량을 의미한다. 이때, 상기 만충전 전압(충전 종지 전압)과 방전 종지 전압은 이차 전지의 종류에 따라 적절하게 선택될 수 있다. 예를 들면, 이차 전지가 NCM 셀인 경우, 상기 정격 용량은 이차 전지를 4.25V까지 충전한 후 0.33C로 2.5V까지 방전시켰을 때의 방전 용량일 수 있다. “단위 용량”은 1Ah를 의미한다. Unless otherwise specified, the capacity of the secondary battery means the rated capacity of the secondary battery. The secondary battery may have a rated capacity of 50 Ah to 200 Ah, preferably 50 Ah to 150 Ah, and more preferably 60 Ah to 140 Ah. “Rated capacity of secondary battery” refers to the electric capacity developed when a fully charged battery is continuously discharged at 0.33C and reaches the discharge end voltage. At this time, the full charge voltage (charge end voltage) and discharge end voltage may be appropriately selected depending on the type of secondary battery. For example, when the secondary battery is an NCM cell, the rated capacity may be the discharge capacity when the secondary battery is charged to 4.25V and then discharged to 2.5V at 0.33C. “Unit capacity” means 1 Ah.
상기 W는 g/Ah의 단위를 가질 수 있으며, 상기 S는 m2 의 단위를 가지며, W/S는 (g/Ah)·m-2의 단위를 가질 수 있다. The W may have a unit of g/Ah, the S may have a unit of m 2 , and the W/S may have a unit of (g/Ah)·m -2 .
상기 W는 2.2g/Ah 이하, 바람직하게는 1.5 내지 2.2g/Ah, 더 바람직하게는 1.7 내지 2.2g/Ah일 수 있으며, 상기 S는 0.01m2 내지 0.2m2, 0.02m2 내지 0.09 m2, 바람직하게는 0.03m2 내지 0.08m2, 더 바람직하게는 0.03m2 내지 0.75m2일 수 있다.The W may be 2.2 g/Ah or less, preferably 1.5 to 2.2 g/Ah, and more preferably 1.7 to 2.2 g/Ah, and the S may be 0.01 m 2 to 0.2 m 2 , 0.02 m 2 to 0.09 m 2 , preferably 0.03m 2 to 0.08m 2 , more preferably 0.03m 2 to 0.75m 2 .
여기서, 이차전지 내 전해액의 중량은 활성화 과정 이후 이차전지 내에 남아있는 전해액의 양을 의미한다. 따라서, 전해질의 총 중량은 이차 전지의 제조 완료 후 또는 작동 중에 존재하는 전해질의 총 중량을 의미할 수 있다.Here, the weight of the electrolyte in the secondary battery refers to the amount of electrolyte remaining in the secondary battery after the activation process. Accordingly, the total weight of the electrolyte may refer to the total weight of the electrolyte present after completion of manufacturing or during operation of the secondary battery.
상기 W/S(단위: (g/Ah)·m-2)는, 예를 들면, 0.1(g/Ah)·m-2 내지 42(g/Ah)·m-2, 1(g/Ah)·m-2 내지 42(g/Ah)·m-2, 5(g/Ah)·m-2 내지 42(g/Ah)·m-2, 10(g/Ah)·m-2 내지 42(g/Ah)·m-2, 또는 20(g/Ah)·m-2 내지 42(g/Ah)·m-2일 수 있으나, 이에 한정되는 것은 아니다. 바람직하게는 상기 W/S(단위: (g/Ah)·m-2)는 30(g/Ah)·m-2 내지 42(g/Ah)·m-2, 더 바람직하게는 35(g/Ah)·m-2 내지 42(g/Ah)·m-2일 수 있다. The W/S (unit: (g/Ah)·m -2 ) is, for example, 0.1 (g/Ah)·m -2 to 42 (g/Ah)·m -2 , 1 (g/Ah) )·m -2 to 42(g/Ah)·m -2 , 5(g/Ah)·m -2 to 42(g/Ah)·m -2 , 10(g/Ah)·m -2 to It may be 42(g/Ah)·m -2 , or 20(g/Ah)·m -2 to 42(g/Ah)·m -2 , but is not limited thereto. Preferably, the W/S (unit: (g/Ah)·m -2 ) is 30 (g/Ah)·m -2 to 42 (g/Ah)·m -2 , more preferably 35 (g /Ah)·m -2 to 42(g/Ah)·m -2 .
상기 이차 전지는 전극 활물질 슬러리를 준비하고, 양극 집전체와 음극 집전체에 이를 적용하여 양극 및 음극을 얻고, 상기 양극의 적어도 하나 이상의 층, 분리막의 적어도 하나 이상의 층을 양극 층과 음극 층 사이에 분리막이 개재되도록 적층하여 전극 조립체를 얻은 다음, 상기 전극 조립체를 파우치, 원통형 캔 또는 각형 캔과 같은 전지 케이스에 수납한 후 상기 전극 조립체에 전해액을 첨가하여 제조될 수 있다. The secondary battery prepares an electrode active material slurry, applies it to a positive electrode current collector and a negative electrode current collector to obtain a positive electrode and a negative electrode, and attaches at least one layer of the positive electrode and at least one layer of the separator between the positive electrode layer and the negative electrode layer. It can be manufactured by stacking the electrode assembly with a separator interposed therebetween, storing the electrode assembly in a battery case such as a pouch, cylindrical can, or square can, and then adding an electrolyte to the electrode assembly.
파우치형 이차 전지는 파우치 필름 적층체를 프레스하여 전극 조립체를 수용할 수 있도록 모양 및 치수 등이 구성된 컵부를 형성한 다음, 상기 컵부에 전극 조립체를 배치하고, 전해액을 첨가한 후, 상기 파우치 필름 적층체의 실링부를 따라 밀봉하여 제조될 수 있다. 캔형 이차 전지는 금속 재질의 캔에 전극 조립체를 수용한 후, 상기 캔에 전해액을 주입하고, 상기 캔의 개구 상에 캡을 실장하여 캔을 밀봉하는 방법으로 제조될 수 있다. 상술한 바와 같이, 상기 캔은 원통형 또는 직사각형, 직육면체 또는 마름모꼴과 같은 각형 형상을 가질 수 있다. The pouch-type secondary battery presses the pouch film laminate to form a cup with a shape and dimension to accommodate the electrode assembly, then places the electrode assembly in the cup, adds an electrolyte, and then stacks the pouch film. It can be manufactured by sealing along the sealing part of the sieve. A can-type secondary battery can be manufactured by placing an electrode assembly in a metal can, injecting an electrolyte into the can, and sealing the can by mounting a cap on the opening of the can. As described above, the can may have a cylindrical or angular shape, such as a rectangle, a cuboid, or a diamond.
이차 전지의 전해질에 대해서는 후술한다. 이차 전지의 전극 조립체에 대해서는 후술한다. 이차 전지의 전지 케이스는 파우치일 수 있으며, 상기 파우치는 이차 전지의 설계 및 제조 분야에서 통상적으로 이해되는 개념으로 사용될 수 있다. 또는 상기 이차전지의 전지 케이스는 본 명세서에 기재된 바와 같이 캔일 수 있다. 전해질의 적어도 일부가 전극 조립체와 전극 조립체와 마주하는 전지 케이스의 내면 사이에 제공될 수 있다. The electrolyte of the secondary battery will be described later. The electrode assembly of the secondary battery will be described later. The battery case of a secondary battery may be a pouch, and the pouch may be used as a commonly understood concept in the field of secondary battery design and manufacturing. Alternatively, the battery case of the secondary battery may be a can as described herein. At least a portion of the electrolyte may be provided between the electrode assembly and the inner surface of the battery case facing the electrode assembly.
특히, 파우치형 이차 전지에서, 상기 전극 조립체는 평면 상에서, 길이 방향으로 연장된 직사각형 형상을 가질 수 있다. 본 명세서에서 전장은, 다른 언급이 없는 한, 길이 방향에서 측정된 길이를 의미한다. 전극 조립체의 폭 방향은 상기 길이 방향에 수직한 방향을 나타내며, 양극, 음극 및 분리막의 적어도 하나 이상의 층의 평면에 배치된다. 본 명세서에서 전폭은 다른 언급이 없는 한 폭 방향에서 측정된 값이다. 전극 조립체에서 양극의 층들, 음극의 층들 및 분리막은 상기 길이 방향 및 폭 방향 모두에 수직한 두께 방향으로 적층될 수 있다. 여기서 평면도는 전극 조립체의 두께 방향에 평행한 시선 방향을 의미할 수 있다. In particular, in a pouch-type secondary battery, the electrode assembly may have a rectangular shape extending in the longitudinal direction on a plane. In this specification, overall length means the length measured in the longitudinal direction, unless otherwise specified. The width direction of the electrode assembly represents a direction perpendicular to the longitudinal direction, and is disposed on the plane of at least one layer of the anode, cathode, and separator. In this specification, the full width is a value measured in the width direction unless otherwise specified. In the electrode assembly, the anode layers, cathode layers, and separator may be stacked in a thickness direction perpendicular to both the longitudinal and width directions. Here, flatness may mean a gaze direction parallel to the thickness direction of the electrode assembly.
캔형 이차 전지의 경우, 상기 전극 조립체는 길이 방향 또는 폭 방향에 평행한 권취 축을 따라 권취될 수 있다. 따라서, 길이 방향과 폭 방향 중 권취 축과 평행하지 않은 다른 쪽 방향은 전극 조립체의 원주 방향과 평행할 수 있다. 캔형 이차 전지의 경우, 전장은 권취된 상태에서 권취축 방향의 전극 조립체의 길이를 의미하고, 전폭은 권취된 상태에서 권취축에 수직한 방향의 전극 조립체의 길이를 의미한다. In the case of a can-type secondary battery, the electrode assembly may be wound along a winding axis parallel to the longitudinal or width direction. Therefore, the other direction of the longitudinal direction and the width direction that is not parallel to the winding axis may be parallel to the circumferential direction of the electrode assembly. In the case of a can-type secondary battery, the overall length refers to the length of the electrode assembly in the direction of the winding axis in the wound state, and the overall width refers to the length of the electrode assembly in the direction perpendicular to the winding axis in the wound state.
전지 케이스는 본 명세서에 개시된 임의의 방식으로 제공될 수 있는 파우치일 수 있다. 구체적으로는, 상기 파우치는 파우치 필름 적층체에 적어도 하나 이상의 컵부를 프레스하여 형성될 수 있다. 이에 따라, 상기 컵부는 파우치 필름 적층체의 나머지 부분으로부터 바깥쪽으로 돌출된 평면부로 형성될 수 있다. 상기 컵부는 트레이 형상(tray-like shape)를 가질 수 있다. 상기 컵부는 파우치 필름 적층체의 나머지 부분과 일체형인 하나 이상의 측벽으로 둘러싸인 평평한 주 표면(main surface)를 포함할 수 있다. 컵부의 상기 평평한 주 표면은 평면 형태의 직사각형의 기본 형상을 가질 수 있으나, 가공 상의 요구사항이나 설계에 따라 모서리가 둥글게 처리될 수 있다. 파우치는, 달리 명시되지 않거나, 기술적으로 부적절하지 않은 한도에서 본 명세서에서 기술되는 파우치의 임의의 특징이나 일부 특징 또는 모든 특징을 가질 수 있다.The battery case may be a pouch that can be provided in any manner disclosed herein. Specifically, the pouch may be formed by pressing at least one cup portion onto a pouch film laminate. Accordingly, the cup portion may be formed as a flat portion protruding outward from the remaining portion of the pouch film laminate. The cup portion may have a tray-like shape. The cup portion may include a flat main surface surrounded by one or more side walls that are integral with the remainder of the pouch film stack. The flat main surface of the cup portion may have a basic shape of a flat rectangle, but the corners may be rounded depending on processing requirements or design. The pouch may have any, some, or all of the features of the pouch described herein, unless otherwise specified or technically inappropriate.
일 구현예에 따르면, 상기 전지 케이스는 파우치 필름 적층체로 제조된 파우치일 수 있다. 상기 파우치, 구체적으로는, 상기 파우치 필름 적층체는 배리어층, 기재층 및 실런트층을 포함할 수 있다. 상기 기재층은 상기 배리어층의 일면 상에 배치될 수 있으며, 상기 실런트층은 상기 배리어층의 타면(즉, 상기 기채층의 반대면)에 배치될 수 있다. 일부 예에서, 상기 기재층, 상기 배리어층 및 상기 실런트층은 파우치 필름 적층체, 구체적으로는 적층 구조를 형성할 수 있다. 상기 파우치, 구체적으로는 상기 파우치 필름 적층체는 파우치의 나머지 부분 또는 상기 파우치 필름 적층체의 나머지 부분으로부터 외부 방향으로 돌출된 적어도 하나의 컵부를 형성하기 위해 프레스 성형(구체적으로는, 연신 성형 및/또는 드로잉)될 수 있다. 상기 전극 조립체는 상기 하나 이상의 컵부에 수용될 수 있다. 상기 적어도 하나의 컵부는 전극 조립체를 수용하기 위한 형상 및 치수를 가질 수 있다. 파우치의 구성요소는 달리 명시되거나, 기술적으로 부적절하지 않은 한도에서, 본 명세서에 개시된 각각의 특징 중 임의 또는 일부 또는 전부의 특징을 구현할 수 있다. 구체적으로는, 상기 기재층, 배리어층 및 실런트층 중 어느 하나는 하기에서 각각 구체적으로 설명되는 바와 같이 구현될 수 있다. According to one embodiment, the battery case may be a pouch made of a pouch film laminate. The pouch, specifically, the pouch film laminate, may include a barrier layer, a base layer, and a sealant layer. The base layer may be disposed on one side of the barrier layer, and the sealant layer may be disposed on the other side of the barrier layer (i.e., the opposite side of the base layer). In some examples, the base layer, the barrier layer, and the sealant layer may form a pouch film laminate, specifically, a laminated structure. The pouch, specifically the pouch film laminate, is press molded (specifically, stretch molded and/or or drawing). The electrode assembly may be accommodated in the one or more cup portions. The at least one cup portion may have a shape and dimension to accommodate the electrode assembly. Components of the pouch may implement any, part, or all of the features disclosed herein, unless otherwise specified or technically inappropriate. Specifically, any one of the base layer, barrier layer, and sealant layer may be implemented as each is described in detail below.
상기 이차 전지는 정격 용량이 50Ah 내지 200Ah, 바람직하게는 50Ah 내지 150Ah, 더 바람직하게는 60Ah 내지 140Ah일 수 있다. The secondary battery may have a rated capacity of 50 Ah to 200 Ah, preferably 50 Ah to 150 Ah, and more preferably 60 Ah to 140 Ah.
상기 전극 조립체는 평면 상에서 실질적으로 직사각형의 형상을 가질 수 있으며, 상기 전극 조립체의 전폭에 대한 전장의 비가 2.5 내지 20, 3 내지 15, 5 내지 10, 또는 5 내지 8일 수 있다. 전극 조립체의 전폭에 대한 전장의 비가 상기 특정 범위를 만족할 때, 전해액 양을 증가시키지 않으면서 마찰력을 증가시키는데 추가로 기여할 수 있다.The electrode assembly may have a substantially rectangular shape in a plane, and a ratio of the overall length to the overall width of the electrode assembly may be 2.5 to 20, 3 to 15, 5 to 10, or 5 to 8. When the ratio of the overall length to the overall width of the electrode assembly satisfies the above specific range, it can further contribute to increasing friction without increasing the amount of electrolyte.
구체적으로는, 상기 전극 조립체는 전장이 200mm 내지 800mm이고, 전폭이 40mm 내지 200mm일 수 있다. 바람직하게는 상기 전극 조립체는 전장이 400mm 내지 600mm이고, 전폭이 50 내지 150mm일 수 있으며, 더 바람직하게는 전장이 500mm 내지 600mm이고, 전폭이 50 내지 100mm일 수 있다. 전극 조립체의 전폭 및 전장이 상기 특정 범위를 만족할 때, 전해액 양을 증가시키지 않으면서 마찰력을 증가시키는데 추가로 기여할 수 있다. 여기서, 상기 전장 및 전폭은 각각 전극 조립체가 평면 상에서 길이 방향 및 폭 방향으로 최대 연장된 길이를 의미할 수 있다.Specifically, the electrode assembly may have a total length of 200 mm to 800 mm and an overall width of 40 mm to 200 mm. Preferably, the electrode assembly may have a total length of 400 mm to 600 mm and an overall width of 50 to 150 mm, and more preferably, the overall length may be 500 mm to 600 mm and an overall width of 50 to 100 mm. When the overall width and overall length of the electrode assembly satisfy the above specific range, it can further contribute to increasing friction without increasing the amount of electrolyte. Here, the full length and full width may mean the maximum extended length of the electrode assembly in the longitudinal and width directions on a plane, respectively.
한편, 상기 전극 조립체의 무게는 500g 내지 1500g, 바람직하게는 550g 내지 1450g, 더 바람직하게는 600g 내지 1400g 일 수 있다. 전극 조립체의 무게가 상기 범위를 만족할 때, 고용량을 구현할 수 있으며, 전극 조립체와 전지 케이스 내면 간의 마찰력이 높아져 내충격성이 우수하게 나타날 수 있다.Meanwhile, the weight of the electrode assembly may be 500g to 1500g, preferably 550g to 1450g, and more preferably 600g to 1400g. When the weight of the electrode assembly satisfies the above range, high capacity can be realized, and the friction between the electrode assembly and the inner surface of the battery case increases, resulting in excellent impact resistance.
한편, 본 발명에 따른 이차 전지는 상기 전극 조립체의 외면에 상기 전극 조립체를 전폭 방향으로 감아서 고정하는 적어도 하나 이상의 고정 부재를 더 포함할 수 있으며, 이때, 상기 고정 부재와 상기 전극 조립체의 접촉 면적이 상기 전극 조립체의 전체 표면적의 30% 이하, 0 ~ 30%, 1 ~ 30%, 5 ~ 30%, 5 ~ 25% 또는 5 ~ 20%일 수 있다. 고정 부재는 일반적으로 마찰 계수가 작은 재질로 이루어지지 때문에 고정 부재의 면적이 증가할 경우, 전극 조립체와 전지 케이스 내면 간의 마찰력이 감소할 수 있다. 따라서, 고정 부재를 사용할 경우, 전극 조립체 간 접촉 면적을 30% 이하로 하여 마찰력 감소를 억제하는 것이 바람직하다. 한편, 상기 전지 케이스는, 파우치형 케이스일 수 있으며, 상기 파우치형 케이스는 배리어층, 상기 배리어층 일면에 형성되는 기재층, 및 상기 배리어층의 타면에 형성되는 실런트층을 포함하며, 일 방향으로 만곡된 적어도 하나 이상의 컵부를 포함하는 파우치일 수 있으며, 상기 파우치의 컵부에 전극 조립체 및 전해질이 수용될 수 있다. Meanwhile, the secondary battery according to the present invention may further include at least one fixing member fixed to the outer surface of the electrode assembly by wrapping the electrode assembly in the full width direction. In this case, the contact area between the fixing member and the electrode assembly. This may be 30% or less, 0 to 30%, 1 to 30%, 5 to 30%, 5 to 25%, or 5 to 20% of the total surface area of the electrode assembly. Since the fixing member is generally made of a material with a low coefficient of friction, when the area of the fixing member increases, the friction between the electrode assembly and the inner surface of the battery case may decrease. Therefore, when using a fixing member, it is desirable to suppress a decrease in friction force by setting the contact area between electrode assemblies to 30% or less. Meanwhile, the battery case may be a pouch-type case, and the pouch-type case includes a barrier layer, a base layer formed on one side of the barrier layer, and a sealant layer formed on the other side of the barrier layer, and is oriented in one direction. It may be a pouch including at least one curved cup portion, and an electrode assembly and an electrolyte may be accommodated in the cup portion of the pouch.
한편, 상기 전극 조립체와 상기 전지 케이스의 내면 사이의 마찰력이 15kgf 이상, 바람직하게는 15kgf 내지 40kgf, 더 바람직하게는 17kgf 내지 35kgf일 수 있다. Meanwhile, the friction force between the electrode assembly and the inner surface of the battery case may be 15 kgf or more, preferably 15 kgf to 40 kgf, and more preferably 17 kgf to 35 kgf.
전극 조립체와 전지 케이스의 내면 사이의 마찰력은 다음과 같이 측정될 수 있다. 전지 케이스의 일부를 절개하고, 양극 탭을 와이어가 연결된 지그로 잡은 다음, 만능재료시험기(UTM)에 와이어를 연결한 후, 등속도, 예를 들면 100mm/min의 속도로 잡아당기면서 걸리는 힘(Force)을 측정하여 전극 조립체와 전지 케이스 내면 사이의 마찰력으로 평가할 수 있다. The friction force between the electrode assembly and the inner surface of the battery case can be measured as follows. Cut a part of the battery case, hold the positive tab with a jig with a wire connected to it, connect the wire to a universal testing machine (UTM), and pull it at a constant speed, for example, 100 mm/min, and measure the force ( Force) can be measured and evaluated as the friction between the electrode assembly and the inner surface of the battery case.
상기 이차 전지는 133.7G × 15.8ms 충돌 조건으로 충돌 쇼크 테스트(crash shock test)을 실시하였을 때, 전해액 누설량이 0일 수 있다. 상기 충돌 쇼크 테스트는 133.7G × 15.8ms 충돌 조건으로 수행되었으며, 충돌 쇼크 테스트 후에, 전지 케이스 외부로 누설된 전해액 중량 및 전지 케이스 내외부의 전극 조립체의 유동 정도를 검사한다. When the secondary battery is subjected to a crash shock test under crash conditions of 133.7G × 15.8ms, the amount of electrolyte leakage may be 0. The impact shock test was performed under 133.7G
일 구현예에 따르면, 상기 전극 조립체는 전장이 0.2m 내지 0.8m, 전폭이 0.05m 내지 0.15m, 단위 용량당 전해액 중량이 1.0 내지 2.8g/Ah일 수 있다. 이 경우, W/S는 30 (g/Ah)·m-² 내지 42 (g/Ah)·m-²일 수 있다. 또 다른 구현예에 따르면, 상기 전극 조립체는 전장이 0.3m 내지 0.8m, 전폭이 0.06m 내지 0.12m, 단위 용량당 전해액 중량이 1.2 내지 2.5g/Ah일 수 있다. 이 경우, W/S는 30 (g/Ah)·m-² 내지 42 (g/Ah)·m-²일 수 있다.According to one embodiment, the electrode assembly may have an overall length of 0.2 m to 0.8 m, an overall width of 0.05 m to 0.15 m, and an electrolyte weight per unit capacity of 1.0 to 2.8 g/Ah. In this case, W/S may be 30 (g/Ah)·m-² to 42 (g/Ah)·m-². According to another embodiment, the electrode assembly may have an overall length of 0.3 m to 0.8 m, an overall width of 0.06 m to 0.12 m, and an electrolyte weight per unit capacity of 1.2 to 2.5 g/Ah. In this case, W/S may be 30 (g/Ah)·m-² to 42 (g/Ah)·m-².
또 다른 구현예에 따르면, 상기 전극 조립체는 전장이 0.4m 내지 0.6m, 전폭이 0.07m 내지 0.11m, 단위 용량당 전해액 중량이 1.5 내지 2.4g/Ah일 수 있다. 이 경우, W/S는 30 (g/Ah)·m-² 내지 42 (g/Ah)·m-²일 수 있다.According to another embodiment, the electrode assembly may have an overall length of 0.4 m to 0.6 m, an overall width of 0.07 m to 0.11 m, and an electrolyte weight per unit capacity of 1.5 to 2.4 g/Ah. In this case, W/S may be 30 (g/Ah)·m-² to 42 (g/Ah)·m-².
다른 측면에서, 본 발명은 전극 조립체, 전해질 및 전지 케이스를 포함하는 이차 전지를 제공할 수 있다. 상기 전극 조립체는 0.01 내지 0.2m2의 표면적을 가질 수 있으며, 상기 전해액의 총 중량이 440g 이하일 수 있다. 상기 전지 케이스는 전극 조립체와 전해질을 수용할 수 있다. 상기 전극 조립체, 전해질 및 전지 케이스는 전극 조립체와 전지 케이스 내면 사이의 마찰력이 15kgf 이상이 되도록 구성될 수 있다.In another aspect, the present invention can provide a secondary battery including an electrode assembly, an electrolyte, and a battery case. The electrode assembly may have a surface area of 0.01 to 0.2 m 2 , and the total weight of the electrolyte may be 440 g or less. The battery case can accommodate an electrode assembly and an electrolyte. The electrode assembly, electrolyte, and battery case may be configured such that the frictional force between the electrode assembly and the inner surface of the battery case is 15 kgf or more.
구체적으로는, 상기 전극 조립체가 직사각형 형상을 가질 경우, 상기 전극 조립체의 표면적은 전장과 전폭의 곱일 수 있다. 전극 조립체의 표면적은 0.02m2 내지 0.08m2, 또는 0.03m2 내지 0.07m2 또는 0.04m2 내지 0.06m2일 수 있다.Specifically, when the electrode assembly has a rectangular shape, the surface area of the electrode assembly may be the product of the full length and the full width. The surface area of the electrode assembly may be 0.02 m 2 to 0.08 m 2 , or 0.03 m 2 to 0.07 m 2 or 0.04 m 2 to 0.06 m 2 .
본 발명에 따른 이차 전지와 같이 전극 조립체의 크기와 단위 용량 당 전해액 양이 특정 조건을 만족할 경우, 전극 조립체와 전지 케이스 사이의 마찰력이 종래에 비해 크게 증가하고, 이로 인해 외부 충격 시에 전극 조립체 이탈 및/또는 전해액 누설이 억제되어 우수한 내충격성을 구현할 수 있다. When the size of the electrode assembly and the amount of electrolyte per unit capacity satisfy certain conditions, such as in the secondary battery according to the present invention, the friction between the electrode assembly and the battery case increases significantly compared to the prior art, and this causes the electrode assembly to break away in the event of an external impact. And/or electrolyte leakage can be suppressed to achieve excellent impact resistance.
도 1은 본 발명의 일 구현예에 따른 이차 전지의 분해 사시도이다. 1 is an exploded perspective view of a secondary battery according to an embodiment of the present invention.
도 2는 일 구현예에 따른 파우치의 구성을 설명하기 위한 도면이다.Figure 2 is a diagram for explaining the configuration of a pouch according to one embodiment.
본 명세서 및 청구범위에 사용된 용어나 단어는 통상적이거나 사전적인 의미로 한정해서 해석되어서는 아니 되며, 발명자는 그 자신의 발명을 가장 최선의 방법으로 설명하기 위해 용어의 개념을 적절하게 정의할 수 있다는 원칙에 입각하여 본 발명의 기술적 사상에 부합하는 의미와 개념으로 해석되어야 한다.Terms or words used in this specification and claims should not be construed as limited to their common or dictionary meanings, and the inventor may appropriately define the concept of terms in order to explain his or her invention in the best way. It should be interpreted with meaning and concept consistent with the technical idea of the present invention based on the principle that it is.
이하, 본 발명을 보다 구체적으로 설명한다.Hereinafter, the present invention will be described in more detail.
최근 전기 자동차용 전지와 같이 고용량이 요구되는 전지에 대한 수요가 증가함에 따라 이차 전지 셀의 정격 용량이 증가하고 있으며, 이에 따라 전극 조립체의 크기 및 무게가 증가하는 추세이다. 그러나 전극 조립체의 크기 및 무게가 증가함에 따라 외부 충격 시에 전극 조립체가 이동하면서 전지 케이스를 손상시키거나, 전지 케이스를 뚫고 나오는 현상이 심화되고 있다. 특히 전지 케이스의 강성이 낮은 파우치형 전지에서 이와 같은 문제가 특히 심각하게 발생하고 있다. 전지 케이스의 손상이 발생하면 전해액이 누설되거나 전극 조립체의 변형이 발생하여 전지 성능 및 안전성에 심각한 문제가 발생한다.Recently, as demand for batteries requiring high capacity, such as batteries for electric vehicles, increases, the rated capacity of secondary battery cells is increasing, and the size and weight of electrode assemblies are increasing accordingly. However, as the size and weight of the electrode assembly increases, the phenomenon of the electrode assembly moving and damaging the battery case or breaking through the battery case during external impact is becoming more severe. In particular, this problem is particularly serious in pouch-type batteries where the rigidity of the battery case is low. If the battery case is damaged, electrolyte may leak or the electrode assembly may be deformed, resulting in serious problems with battery performance and safety.
한편, 전극 조립체의 표면 및 전지 케이스 내면에는 전극 조립체에 함침되고 남은 전해질이 잔존할 수 있는데, 전해질은 습윤 특성을 가지기 때문에 전지 케이스의 내면과 전극 조립체의 표면에 전해질이 존재할 경우, 전극 조립체와 전지 케이스 내부 표면 사이의 마찰력이 감소하고, 이로 인해 외부 충격 시에 전극 조립체의 유동이 더욱 심화된다. 이차 전지 내 전해액 총량이 증가할 경우 전극 조립체와 전지 케이스 내면에 잔존하는 전해액 양이 증가하게 되고, 이로 인해 마찰력이 더욱 감소하게 된다. 따라서, 내충격성 측면에서는 이차 전지 내의 전해액 양이 작을수록 좋으나, 전해액의 양이 너무 적으면, 이차 전지의 용량에 악영향을 미칠 수 있으며, 이차 전지의 작동성 및 수명을 저하시킬 수 있다. Meanwhile, electrolyte remaining after impregnating the electrode assembly may remain on the surface of the electrode assembly and the inner surface of the battery case. Since the electrolyte has wet characteristics, if electrolyte is present on the inner surface of the battery case and the surface of the electrode assembly, the electrode assembly and the battery The friction between the inner surfaces of the case is reduced, which further increases the flow of the electrode assembly upon external impact. When the total amount of electrolyte in the secondary battery increases, the amount of electrolyte remaining inside the electrode assembly and the battery case increases, which further reduces friction. Therefore, in terms of impact resistance, the smaller the amount of electrolyte in the secondary battery, the better. However, if the amount of electrolyte is too small, the capacity of the secondary battery may be adversely affected and the operability and lifespan of the secondary battery may be reduced.
본 발명자들은 전지의 전기화학적 성능과 내충격성을 모두 우수하게 구현할 수 있는 이차 전지를 개발하기 위해 연구를 거듭한 결과, 전극 조립체의 단면적, 전해액 함량 및 이차 전지 용량이 특정 조건을 만족할 경우, 전극 조립체와 전지 케이스 사이의 마찰력이 종래에 비해 크게 증가하고, 이로 인해 외부 충격 시에 전극 조립체 이탈에 의한 전지 케이스의 손상이 억제되어 우수한 내충격성을 구현하면서도 전기화학적 물성 저하를 최소화할 수 있음을 알아내고 본 발명을 완성하였다. The present inventors have conducted repeated research to develop a secondary battery that can achieve excellent both electrochemical performance and impact resistance of the battery. As a result, when the cross-sectional area of the electrode assembly, electrolyte content, and secondary battery capacity meet specific conditions, the electrode assembly It was found that the friction between the battery case and the battery case is greatly increased compared to the prior art, and as a result, damage to the battery case due to separation of the electrode assembly during external impact is suppressed, making it possible to minimize the degradation of electrochemical properties while realizing excellent impact resistance. The present invention has been completed.
본 발명에 따른 이차 전지는, 전극 조립체, 전해질 및 상기 전극 조립체 및 전해질을 수용하기 위한 수용부를 포함하는 전지 케이스;를 포함하고, 하기 식 (1)을 만족하는 것을 그 특징으로 한다. The secondary battery according to the present invention includes a battery case including an electrode assembly, an electrolyte, and a receiving portion for accommodating the electrode assembly and the electrolyte, and is characterized by satisfying the following equation (1).
식 (1): W / S ≤ 42Equation (1): W/S ≤ 42
상기 식 (1)의 W/S의 단위는 (g/Ah)·m-²이다. 상기 W(단위: g/Ah)는 상기 이차 전지의 단위 용량당 전해액 중량이며, 이차 전지 내의 전해액 총 중량(단위: g)을 이차 전지의 정격 용량(단위: Ah)으로 나누어 측정할 수 있다. 한편, 상기 이차 전지 내의 전해액 총 중량은 활성화 공정 이후에 이차 전지 내에 잔존하는 전해액의 총 중량을 의미한다. The unit of W/S in equation (1) above is (g/Ah)·m-². The W (unit: g/Ah) is the weight of electrolyte per unit capacity of the secondary battery, and can be measured by dividing the total weight of electrolyte in the secondary battery (unit: g) by the rated capacity of the secondary battery (unit: Ah). Meanwhile, the total weight of the electrolyte in the secondary battery refers to the total weight of the electrolyte remaining in the secondary battery after the activation process.
바람직하게는 상기 W/S(단위: (g/Ah)·m-2)는, 42(g/Ah)·m-2 이하, 0.1(g/Ah)·m-2 내지 42(g/Ah)·m-2, 1(g/Ah)·m-2 내지 42(g/Ah)·m-2, 5(g/Ah)·m-2 내지 42(g/Ah)·m-2, 10(g/Ah)·m-2 내지 42(g/Ah)·m-2, 또는 20(g/Ah)·m-2 내지 42(g/Ah)·m-2일 수 있으나, 이에 한정되는 것은 아니다. 바람직하게는 상기 W/S(단위: (g/Ah)·m-2)는 30(g/Ah)·m-2 내지 42(g/Ah)·m-2, 더 바람직하게는 35(g/Ah)·m-2 내지 42(g/Ah)·m-2일 수 있다. W/S가 42(g/Ah)·m-2 이하인 경우에 전극 조립체와, 상기 전극 조립체와 접촉되는 전지 케이스 내면(예를 들면, 파우치의 컵부 바닥면) 간의 마찰력이 크게 증가하고, 이로 인해 외부 충격이 가해졌을 때 전극 조립체의 이탈이 최소화되어 전지 케이스 손상으로 인한 전해액 누설을 최소화할 수 있다. Preferably, the W/S (unit: (g/Ah)·m -2 ) is 42 (g/Ah)·m -2 or less, 0.1 (g/Ah)·m -2 to 42 (g/Ah) )·m -2 , 1(g/Ah)·m -2 to 42(g/Ah)·m -2 , 5(g/Ah)·m -2 to 42(g/Ah)·m -2 , It may be 10(g/Ah)·m -2 to 42(g/Ah)·m -2 , or 20(g/Ah)·m -2 to 42(g/Ah)·m -2 , but is limited thereto. It doesn't work. Preferably, the W/S (unit: (g/Ah)·m -2 ) is 30 (g/Ah)·m -2 to 42 (g/Ah)·m -2 , more preferably 35 (g /Ah)·m -2 to 42(g/Ah)·m -2 . When W/S is 42(g/Ah)·m -2 or less, the friction between the electrode assembly and the inner surface of the battery case (for example, the bottom surface of the cup of the pouch) in contact with the electrode assembly greatly increases, resulting in When external shock is applied, separation of the electrode assembly is minimized, thereby minimizing electrolyte leakage due to damage to the battery case.
한편, 상기 W는, 전극 조립체의 크기에 따라 달라질 수 있으나, 예를 들면, 2.2g/Ah 이하, 바람직하게는 1.5g/Ah 내지 2.2g/Ah, 더 바람직하게는 1.7 g/Ah 내지 2.2g/Ah일 수 있다. W가 너무 크면 전극 조립체와 전지 케이스 내면 사이의 마찰력 증가 효과가 미미하고, 너무 작으면 전지 구동 시에 전해액이 충분하지 않아 전지 성능이 저하될 수 있다.Meanwhile, the W may vary depending on the size of the electrode assembly, but for example, 2.2 g/Ah or less, preferably 1.5 g/Ah to 2.2 g/Ah, more preferably 1.7 g/Ah to 2.2 g. It could be /Ah. If W is too large, the effect of increasing friction between the electrode assembly and the inner surface of the battery case is minimal, and if W is too small, battery performance may deteriorate due to insufficient electrolyte during battery operation.
한편, 상기 S는 상기 전극 조립체의 단면적으로, 전극 조립체의 전장과 전폭을 곱한 값이다, 이때, 상기 전장 및 전폭은 m 단위로 측정한 값을 사용한다. Meanwhile, S is the cross-sectional area of the electrode assembly, which is a value obtained by multiplying the full length and full width of the electrode assembly. In this case, the full length and full width are measured in m units.
상기 S는, 예를 들면, 0.02 내지 0.09m2, 바람직하게는 0.03 내지 0.08m2, 더 바람직하게는 0.03 내지 0.75m2일 수 있다. S가 너무 작으면 전지 용량이 감소하고, 전극 조립체와 전지 케이스 간의 마찰력 증가 효과가 미미하고, 너무 크면, 안정성 이슈가 발생했을 때 사고 발생 위험이 더 크다는 문제점이 있다.The S may be, for example, 0.02 to 0.09 m 2 , preferably 0.03 to 0.08 m 2 , and more preferably 0.03 to 0.75 m 2 . If S is too small, the battery capacity decreases and the effect of increasing friction between the electrode assembly and the battery case is minimal, and if S is too large, there is a greater risk of accidents when a stability issue occurs.
상기 이차 전지는 정격 용량이 50Ah 내지 200Ah, 바람직하게는 50Ah 내지 150Ah, 더 바람직하게는 60Ah 내지 140Ah일 수 있다. 이차 전지의 정격 용량이 상기 범위를 만족할 때, 고용량의 이차 전지를 구현할 수 있다. The secondary battery may have a rated capacity of 50 Ah to 200 Ah, preferably 50 Ah to 150 Ah, and more preferably 60 Ah to 140 Ah. When the rated capacity of the secondary battery satisfies the above range, a high capacity secondary battery can be implemented.
한편, 본 발명에 따른 이차 전지는 파우치형 이차 전지일 수 있다. 이 경우, 상기 전지 케이스는, 예를 들면, 배리어층, 상기 배리어층 일면에 형성되는 기재층, 및 상기 배리어층의 타면에 형성되는 실런트층을 포함하며, 일 방향으로 만입된 적어도 하나 이상의 컵부를 포함하는 파우치일 수 있으며, 상기 파우치의 컵부에 전극 조립체 및 전해질이 수용될 수 있다.Meanwhile, the secondary battery according to the present invention may be a pouch-type secondary battery. In this case, the battery case includes, for example, a barrier layer, a base layer formed on one side of the barrier layer, and a sealant layer formed on the other side of the barrier layer, and at least one cup portion indented in one direction. It may be a pouch containing an electrode assembly and an electrolyte in the cup portion of the pouch.
한편, 상기 식 (1)의 조건을 만족할 경우, 상기 전극 조립체와 전지 케이스의 내면(예를 들면, 파우치 컵부의 바닥면) 사이의 마찰력이 15kgf 이상, 바람직하게는 15kgf 내지 40kgf, 더 바람직하게는 17kgf 내지 35kgf으로 높아 외부 충격에 의한 전극 조립체 이탈이 적어 파우치 손상을 최소화되고 이로 인해 내충격성이 매우 우수하게 나타난다. On the other hand, when the conditions of equation (1) are satisfied, the friction force between the electrode assembly and the inner surface of the battery case (for example, the bottom surface of the pouch cup portion) is 15 kgf or more, preferably 15 kgf to 40 kgf, more preferably It is high at 17kgf to 35kgf, which minimizes damage to the pouch as there is little separation of the electrode assembly due to external impact, and this results in excellent impact resistance.
이때, 상기 전극 조립체와 전지 케이스 내면 사이의 마찰력은, 하기 방법으로 측정될 수 있다.At this time, the friction force between the electrode assembly and the inner surface of the battery case can be measured by the following method.
먼저, 전지 케이스의 일부를 절개하고, 양극 탭을 와이어가 연결된 지그로 잡은 다음, 만능재료시험기(UTM)에 상기 와이어를 연결한 후, 등속도, 예를 들면 100mm/min의 속도로 잡아당기면서 걸리는 힘(Force)을 측정하여 전극 조립체와 전지 케이스 내면 사이의 마찰력으로 평가할 수 있다. First, cut a part of the battery case, hold the positive tab with a jig connected to the wire, then connect the wire to a universal testing machine (UTM) and pull it at a constant speed, for example, 100 mm/min. The applied force can be measured and evaluated as the friction between the electrode assembly and the inner surface of the battery case.
한편, 본 발명에 따른 이차 전지는, 전극 조립체와 전지 케이스 간 마찰력이 높아, 외부 충격 시의 전극 조립체의 이탈이 최소화되며, 이로 인해 우수한 내충격성을 갖는다. 예를 들면, 본 발명에 따른 이차 전지는, 133.7G × 15.8ms 충돌 조건으로 충돌 쇼크 테스트(crash shock test)을 실시하였을 때, 전해액 누설이 발생하지 않는다. 즉, 본 발명에 따른 이차 전지는 133.7G × 15.8ms 충돌 조건으로 충돌 쇼크 테스트(crash shock test) 후의 전해액 누설량이 0이다.On the other hand, the secondary battery according to the present invention has high friction between the electrode assembly and the battery case, minimizing separation of the electrode assembly during external impact, and thus has excellent impact resistance. For example, in the secondary battery according to the present invention, electrolyte leakage does not occur when a crash shock test is performed under a crash condition of 133.7G × 15.8ms. That is, the secondary battery according to the present invention has an electrolyte leakage amount of 0 after a crash shock test under a crash condition of 133.7G × 15.8ms.
상기 충돌 쇼크 테스트(crash shock test)는 측정 대상 전지를 낙하 충격 장비의 지그에 장착한 다음, 상기 전지를 특정 높이에서 자유 낙하시킨 후 전지의 손상 여부를 판단하는 방법으로 수행될 수 있다. 이때, 상기 자유 낙하 높이는 측정하고자 하는 충돌 조건(가속도 × duration time)을 고려하여 설정된다. 구체적으로는 측정하고자 하는 충돌 조건에서의 충격 에너지를 위치 에너지로 환산한 후, 측정 대상 전지의 무게를 고려하여 상기 환산된 위치 에너지를 가질 수 있는 높이를 계산하여 자유 낙하 높이를 설정할 수 있다. 한편, 전지 손상 여부는 전해액 누액 유무로 평가할 수 있다.The crash shock test can be performed by mounting the battery to be measured on a jig of drop shock equipment, letting the battery fall freely from a certain height, and then determining whether the battery is damaged. At this time, the free fall height is set in consideration of the collision condition (acceleration × duration time) to be measured. Specifically, the impact energy in the collision condition to be measured can be converted into potential energy, and then the free fall height can be set by calculating the height that can have the converted potential energy by considering the weight of the battery to be measured. Meanwhile, damage to the battery can be evaluated by whether electrolyte leaks or not.
도 1은 본 발명에 따른 이차 전지의 일 구현예인 파우치형 이차 전지의 분해 사시도이며, 도 2는 파우치 필름 적층체의 단면을 도시한 도면이다. 이하, 도면을 참조하여, 본 발명의 일 구현예에 따른 이차 전지를 보다 자세히 설명한다. FIG. 1 is an exploded perspective view of a pouch-type secondary battery, which is an example of a secondary battery according to the present invention, and FIG. 2 is a cross-sectional view of a pouch film laminate. Hereinafter, with reference to the drawings, a secondary battery according to an embodiment of the present invention will be described in more detail.
파우치pouch
상기 파우치(100)는 전극 조립체 및 전해질을 수용하기 위한 전지 케이스로, 배리어층(20), 상기 배리어층 일면에 형성되는 기재층(10), 및 상기 배리어층의 타면에 형성되는 실런트층(30)을 포함하고, 일 방향으로 만입된 적어도 하나 이상의 컵부(수용부)를 포함한다. The pouch 100 is a battery case for accommodating an electrode assembly and an electrolyte, and includes a barrier layer 20, a base layer 10 formed on one side of the barrier layer, and a sealant layer 30 formed on the other side of the barrier layer. ) and includes at least one cup portion (receiving portion) indented in one direction.
구체적으로는, 상기 파우치(100)는 유연성을 가지며, 기재층(10), 배리어층(20), 실런트층(30)이 순차적으로 적층된 파우치 필름 적층체를 프레스 성형 장치에 삽입하고, 상기 파우치 필름 적층체의 일부 영역에 펀치로 압력을 가하여 연신시킴으로써 일 방향으로 만입된 형상의 컵부를 형성하는 방법으로 제조될 수 있다. Specifically, the pouch 100 has flexibility, and a pouch film laminate in which a base layer 10, a barrier layer 20, and a sealant layer 30 are sequentially laminated is inserted into a press molding device, and the pouch is formed. It can be manufactured by applying pressure to a portion of the film laminate with a punch and stretching it to form a cup portion that is indented in one direction.
기재층base layer
기재층(10)은 파우치의 최외층에 배치되어 전극 조립체를 외부 충격으로부터 보호하고 전기적으로 절연시키기 위한 것이다. The base layer 10 is disposed on the outermost layer of the pouch to protect the electrode assembly from external shock and electrically insulate it.
상기 기재층(10)은 폴리머 재질로 이루어질 수 있으며, 예를 들면, 폴리에틸렌, 폴리프로필렌, 폴리카보네이트, 폴리에틸렌테레프탈레이트, 폴리염화비닐, 아크릴계 고분자, 폴리아크릴로나이트릴, 폴리이미드, 폴리아마이드, 셀룰로오스, 아라미드, 나일론, 폴리에스테르, 폴리파라페닐렌벤조비스옥사졸, 폴리아릴레이트, 및 테프론으로 이루어진 군으로부터 선택된 1종 이상의 폴리머 재질로 이루어질 수 있다. The base layer 10 may be made of a polymer material, for example, polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, polyvinyl chloride, acrylic polymer, polyacrylonitrile, polyimide, polyamide, cellulose. , aramid, nylon, polyester, polyparaphenylenebenzobisoxazole, polyarylate, and Teflon.
상기 기재층(10)은 단층 구조일 수도 있고, 도 2에 도시된 바와 같이 서로 다른 폴리머 필름들(12, 14)이 적층된 다층 구조일 수도 있다. 기재층(10)이 다층 구조인 경우, 폴리머 필름들 사이에 접착층(16a)이 개재될 수 있다. The base layer 10 may have a single-layer structure or a multi-layer structure in which different polymer films 12 and 14 are stacked, as shown in FIG. 2 . When the base layer 10 has a multilayer structure, an adhesive layer 16a may be interposed between the polymer films.
한편, 상기 기재층(10)은 전체 두께가 10㎛ ~ 60㎛, 바람직하게는 20㎛ ~ 50㎛, 더 바람직하게는 30㎛ ~ 50㎛일 수 있다. 기재층이 다층 구조인 경우, 상기 두께는 접착층을 포함하는 두께이다. 기재층(10)가 상기 범위를 만족할 때, 내구성, 절연성 및 성형성이 우수하게 나타난다. 기재층 두께가 너무 얇으면 내구성이 떨어지고, 성형 과정에서 기재층 파손이 발생할 수 있으며, 너무 두꺼우면 성형성이 저하될 수 있고, 파우치의 전체 두께가 증가하고, 전지 수용 공간이 감소되어 에너지 밀도가 저하될 수 있다. Meanwhile, the base layer 10 may have a total thickness of 10 μm to 60 μm, preferably 20 μm to 50 μm, and more preferably 30 μm to 50 μm. When the base layer has a multilayer structure, the thickness includes the adhesive layer. When the base layer 10 satisfies the above range, durability, insulation, and moldability are excellent. If the thickness of the base layer is too thin, durability decreases and damage to the base layer may occur during the molding process. If it is too thick, moldability may decrease, the overall thickness of the pouch increases, and the battery storage space decreases, lowering the energy density. may deteriorate.
일 구현예에 따르면, 상기 기재층(10)은, 폴리에틸렌테레프탈레이트 (PolyEthyleneTerephtalate; PET) 필름과 나일론(Nylon) 필름의 적층 구조일 수 있다. 이때, 상기 나일론 필름이 배리어층(20) 측, 즉, 내측으로 배치되고, 폴리에틸렌테레프탈레이트 필름이 파우치의 표면 측으로 배치되는 것이 바람직하다. According to one embodiment, the base layer 10 may have a laminated structure of a polyethylene terephthalate (PET) film and a nylon film. At this time, it is preferable that the nylon film is disposed on the barrier layer 20 side, that is, on the inside, and the polyethylene terephthalate film is disposed on the surface side of the pouch.
폴리에틸렌테레프탈레이트(PET)는 내구성 및 전기 절연성이 우수하여 PET 필름이 표면 측에 배치될 때, 내구성 및 절연성이 우수하게 나타난다. 다만, PET 필름의 경우, 배리어층(20)을 구성하는 알루미늄 합금 박막과의 접착성이 약하고, 연신 거동도 상이하기 때문에 PET 필름을 배리어층 측에 배치할 경우, 성형 과정에서 기재층과 배리어층의 박리가 발생할 수 있고, 배리어층이 균일하게 연신되지 않아 성형성이 저하되는 문제가 발생할 수 있다. 이에 비해, 나일론 필름은 배리어층(20)을 구성하는 알루미늄 합금 박막과 연신 거동이 유사하기 때문에, 폴리에틸렌테레프탈레이트와 배리어층 사이에 나일론 필름을 배치할 경우 성형성 개선 효과를 얻을 수 있다. Polyethylene terephthalate (PET) has excellent durability and electrical insulation, so when the PET film is placed on the surface, durability and insulation are excellent. However, in the case of PET film, the adhesiveness with the aluminum alloy thin film constituting the barrier layer 20 is weak and the stretching behavior is also different. Therefore, when the PET film is placed on the barrier layer side, the base layer and the barrier layer are separated during the molding process. Peeling may occur, and the barrier layer may not be stretched uniformly, which may cause problems with reduced formability. In contrast, since the nylon film has similar stretching behavior to the aluminum alloy thin film constituting the barrier layer 20, the formability improvement effect can be obtained when the nylon film is placed between polyethylene terephthalate and the barrier layer.
상기 폴리에틸렌테레프탈레이트 필름은 그 두께가 5㎛ 내지 20㎛, 바람직하게는 5㎛ 내지 15㎛, 더 바람직하게는 7㎛ 내지 15㎛일 수 있으며, 상기 나일론 필름은 그 두께가 2010㎛ 내지 40㎛, 바람직하게는 2010㎛ 내지 35㎛, 더 바람직하게는 2515㎛ 내지 25㎛일 수 있다. 폴리에틸렌테레프탈레이트 필름과 나일론 필름의 두께가 상기 범위를 만족할 때, 성형성 및 성형 후 강성이 우수하게 나타난다.The polyethylene terephthalate film may have a thickness of 5㎛ to 20㎛, preferably 5㎛ to 15㎛, more preferably 7㎛ to 15㎛, and the nylon film may have a thickness of 2010㎛ to 40㎛, Preferably it may be 2010㎛ to 35㎛, more preferably 2515㎛ to 25㎛. When the thickness of the polyethylene terephthalate film and the nylon film satisfies the above range, excellent moldability and rigidity after molding are exhibited.
배리어층barrier layer
배리어층(20)은 파우치(100)의 기계적 강도를 확보하고, 이차 전지 외부의 가스 또는 수분 등의 출입을 차단하며, 전해질의 누수를 방지하기 위한 것이다. The barrier layer 20 is used to secure the mechanical strength of the pouch 100, block gas or moisture from entering the secondary battery, and prevent electrolyte leakage.
상기 배리어층(20)은 그 두께가 40㎛ 내지 100㎛, 더 바람직하게는 50㎛ 내지 80㎛, 더 바람직하게는 60㎛ 내지 80㎛일 수 있다. 배리어층 두께가 상기 범위를 만족할 경우, 성형성이 개선되어 컵부 성형 깊이를 증가시키거나 2컵 성형 시에도 크랙 및/또는 핀홀 발생이 적어 성형 후 외부 스트레스에 대한 저항성이 개선된다. The barrier layer 20 may have a thickness of 40 μm to 100 μm, more preferably 50 μm to 80 μm, and more preferably 60 μm to 80 μm. When the barrier layer thickness satisfies the above range, formability is improved and the molding depth of the cup portion is increased or cracks and/or pinholes are less likely to occur even when molding two cups, thereby improving resistance to external stress after molding.
한편, 상기 배리어층(20)은 금속 재질로 이루어질 수 있으며, 구체적으로는 알루미늄 합금 박막으로 이루어질 수 있다. Meanwhile, the barrier layer 20 may be made of a metal material, and specifically, may be made of an aluminum alloy thin film.
상기 알루미늄 합금 박막은 알루미늄과, 상기 알루미늄 이외의 금속 원소, 예를 들어, 철(Fe), 구리(Cu), 크롬(Cr), 망간(Mn), 니켈(Ni), 마그네슘(Mg), 실리콘(Si) 및 아연(Zn)으로 이루어진 군으로부터 선택되는 1종 또는 2종 이상이 포함할 수 있다. The aluminum alloy thin film includes aluminum and metal elements other than aluminum, such as iron (Fe), copper (Cu), chromium (Cr), manganese (Mn), nickel (Ni), magnesium (Mg), and silicon. It may include one or two or more types selected from the group consisting of (Si) and zinc (Zn).
바람직하게는, 상기 알루미늄 합금 박막은, 철(Fe) 함유량이 1.2wt% 내지 1.7wt%, 바람직하게는 1.3wt% 내지 1.7wt%, 더 바람직하게는 1.3wt% 내지 1.45wt%일 수 있다. 알루미늄 합금 박막 내의 철(Fe) 함유량이 상기 범위를 만족할 경우, 컵부를 깊게 형성하는 경우에도 크랙이나 핀홀 발생을 최소화할 수 있다. Preferably, the aluminum alloy thin film may have an iron (Fe) content of 1.2 wt% to 1.7 wt%, preferably 1.3 wt% to 1.7 wt%, and more preferably 1.3 wt% to 1.45 wt%. When the iron (Fe) content in the aluminum alloy thin film satisfies the above range, the occurrence of cracks or pinholes can be minimized even when the cup portion is formed deeply.
실런트층Sealant layer
실런트층(30)은 열 압착을 통해 접착되어 파우치를 밀봉하기 위한 것으로, 파우치 필름 적층체(1)의 최내층에 위치한다. The sealant layer 30 is bonded through heat compression to seal the pouch, and is located in the innermost layer of the pouch film laminate 1.
실런트층(30)은 파우치가 성형된 후에 전해질 및 전극 조립체와 접촉되는 면이기 때문에 절연성 및 내식성을 가져야 하며, 내부를 완전히 밀폐하여 내부 및 외부간의 물질 이동을 차단해야 하므로, 높은 실링성을 가져야 한다.Since the sealant layer 30 is the surface that comes into contact with the electrolyte and electrode assembly after the pouch is molded, it must have insulation and corrosion resistance. It must completely seal the interior to block material movement between the inside and the outside, so it must have high sealing properties. .
상기 실런트층(30)은, 폴리머 재질로 이루어질 수 있으며, 예를 들면, 폴리에틸렌, 폴리프로필렌, 폴리카보네이트, 폴리에틸렌테레프탈레이트, 폴리염화비닐, 아크릴계 고분자, 폴리아크릴로나이트릴, 폴리이미드, 폴리아마이드, 셀룰로오스, 아라미드, 나일론, 폴리에스테르, 폴리파라페닐렌벤조비스옥사졸, 폴리아릴레이트, 및 테프론으로 이루어진 군으로부터 선택된 1종 이상으로 이루어질 수 있으며, 이 중에서도 인장강도, 강성, 표면경도, 내마모성, 내열성 등의 기계적 물성과 내식성 등의 화학적 물성이 뛰어난 폴리프로필렌(PP)을 포함하는 것이 특히 바람직하다.The sealant layer 30 may be made of a polymer material, for example, polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, polyvinyl chloride, acrylic polymer, polyacrylonitrile, polyimide, polyamide, It may be made of one or more selected from the group consisting of cellulose, aramid, nylon, polyester, polyparaphenylenebenzobisoxazole, polyarylate, and Teflon, among which tensile strength, rigidity, surface hardness, abrasion resistance, and heat resistance. It is particularly preferable to include polypropylene (PP), which has excellent mechanical properties and chemical properties such as corrosion resistance.
보다 구체적으로는 상기 실런트층(30)은, 폴리프로필렌, 무연신 폴리프로필렌(Cast Polypropylene; CPP), 산 변성된 폴리프로필렌(Acid Modified Polypropylene), 폴리프로필렌-부틸렌-에틸렌 공중합체 또는 이들의 조합을 포함하는 것일 수 있다. More specifically, the sealant layer 30 is polypropylene, cast polypropylene (CPP), acid modified polypropylene, polypropylene-butylene-ethylene copolymer, or a combination thereof. It may include.
상기 실런트층(30)은 단일층 구조일 수도 있고, 서로 다른 폴리머 재질로 이루어진 2 이상의 층을 포함하는 다층 구조일 수도 있다. The sealant layer 30 may have a single-layer structure or a multi-layer structure including two or more layers made of different polymer materials.
상기 실런트층은 총 두께가 60㎛ 내지 100㎛, 바람직하게는 60㎛ 내지 90㎛, 더 바람직하게는 70㎛ 내지 90㎛일 수 있다. 실런트층의 두께가 너무 얇으면 실링 내구성 및 절연성이 떨어질 수 있으며, 너무 두꺼우면 굴곡성이 떨어지고 파우치 필름 적층체 총 두께가 증가하여 부피 대비 에너지 밀도가 저하될 수 있다. The sealant layer may have a total thickness of 60 ㎛ to 100 ㎛, preferably 60 ㎛ to 90 ㎛, more preferably 70 ㎛ to 90 ㎛. If the thickness of the sealant layer is too thin, sealing durability and insulation may be reduced, and if it is too thick, flexibility may decrease and the total thickness of the pouch film laminate may increase, resulting in a decrease in energy density relative to volume.
상기 파우치 필름 적층체(1)는, 당해 기술 분야에 알려진 파우치 필름 적층체의 제조 방법을 통해 제조될 수 있다. 예를 들면, 파우치 필름 적층체는, 배리어층(20) 상면에 접착제를 통해 기재층(10)을 부착하고, 상기 배리어층(20)의 하면에 공압출이나 접착제를 통해 실런트층(30)을 형성하는 방법을 통해 제조될 수 있으나, 이에 한정되는 것은 아니다. The pouch film laminate 1 can be manufactured through a pouch film laminate manufacturing method known in the art. For example, in the pouch film laminate, the base layer 10 is attached to the upper surface of the barrier layer 20 through an adhesive, and the sealant layer 30 is attached to the lower surface of the barrier layer 20 through coextrusion or adhesive. It can be manufactured through a forming method, but is not limited to this.
상기와 같은 파우치 필름 적층체를 성형 장치에 삽입하고, 파우치 필름 적층체의 일부 영역에 펀치로 압력을 가하여 컵부를 형성함으로써 파우치(100)를 제조한다. 이때, 상기 압력은 0.3MPa 내지 1MPa, 바람직하게는 0.3MPa 내지 0.8MPa, 더 바람직하게는 0.4MPa 내지 0.6MPa 정도일 수 있다. 컵부 성형 시 압력이 너무 낮으면 드로잉이 과하게 발생하여 주름이 발생할 수 있고, 너무 높으면 드로잉이 잘 되지 않아 성형 깊이가 낮아질 수 있다.The pouch 100 is manufactured by inserting the pouch film laminate as described above into a molding device and applying pressure to a portion of the pouch film laminate with a punch to form a cup portion. At this time, the pressure may be 0.3 MPa to 1 MPa, preferably 0.3 MPa to 0.8 MPa, and more preferably 0.4 MPa to 0.6 MPa. If the pressure is too low when molding the cup portion, excessive drawing may occur and wrinkles may occur, and if it is too high, drawing may not occur well and the molding depth may be reduced.
한편, 상기 펀치의 이동 속도는 20mm/min 내지 80mm/min, 바람직하게는 30mm/min 내지 70mm/min, 더 바람직하게는 40mm/min 내지 60mm/min일 수 있다. 성형 시 압력이 너무 작거나, 펀치의 이동 속도가 너무 빠르면 좌굴(buckling)에 의한 주름(wrinkle)이 발생할 수 있으며, 성형 시 압력이 너무 크거나, 펀치의 이동 속도가 너무 느리면, 성형 시 컵부 코너에 집중되는 응력이 커져서 핀홀이나 크랙 발생이 증가할 수 있다. Meanwhile, the moving speed of the punch may be 20 mm/min to 80 mm/min, preferably 30 mm/min to 70 mm/min, and more preferably 40 mm/min to 60 mm/min. If the pressure during molding is too small or the moving speed of the punch is too fast, wrinkles may occur due to buckling. If the pressure during molding is too large or the moving speed of the punch is too slow, cup corners may appear during molding. As the stress concentrated in increases, the occurrence of pinholes or cracks may increase.
상기와 같은 방법을 통해 제조된 본 발명의 파우치(100)는 하부 케이스(101), 상부 케이스(102) 및 상기 하부 케이스와 하부 케이스를 연결하는 폴딩부(130)을 포함하며, 상기 상부 케이스 및/또는 하부 케이스는 일 방향으로 만입된 형상의 컵부(110)를 포함한다. The pouch 100 of the present invention manufactured through the method described above includes a lower case 101, an upper case 102, and a folding portion 130 connecting the lower case and the lower case. /Or the lower case includes a cup portion 110 that is indented in one direction.
구체적으로는, 본 발명에 따른 파우치(100)는, 도 1에 도시된 바와 같이, 하부 케이스(101)에만 컵부(110)가 형성된 1컵 형태일 수도 있으나, 이에 한정되는 것은 아니며, 상부 케이스 및 하부 케이스 모두에 컵부가 형성된 2컵 형태일 수도 있다. 2컵 형태의 파우치의 경우, 전극 조립체 및 전해질 수용 후, 상부 케이스의 컵부와 하부 케이스의 컵부가 서로 마주보도록 상부 케이스를 폴딩하기 때문에 1컵 형태의 파우치에 비해 두께가 더 두꺼운 전극 조립체를 수용할 수 있고, 이에 따라 고 에너지 밀도 구현에 유리하다는 장점이 있다. Specifically, as shown in FIG. 1, the pouch 100 according to the present invention may have a 1-cup shape with the cup portion 110 formed only in the lower case 101, but is not limited thereto, and includes the upper case and It may be a two-cup type with cup portions formed on both lower cases. In the case of a 2-cup pouch, after accommodating the electrode assembly and electrolyte, the upper case is folded so that the cup portion of the upper case and the cup portion of the lower case face each other, so it can accommodate a thicker electrode assembly than a 1-cup pouch. This has the advantage of being advantageous in realizing high energy density.
상기 컵부(110)는 전극 조립체(200)를 수용하기 위한 수용 공간을 갖는다. 한편, 상기 파우치(100)는 컵부(110) 주변부에 테라스(120)를 포함할 수 있다. 상기 테라스(120)는 파우치 필름 적층체에서 성형되지 않은 부분, 즉, 컵부(110)를 제외한 나머지 영역을 의미한다. 상기 테라스(129)는 전극 조립체(200)를 컵부(110)에 수용하고, 전해액을 주입한 후 실링하는 공정에서 열 접착을 통해 실링되는 부분이다.The cup portion 110 has a receiving space for accommodating the electrode assembly 200. Meanwhile, the pouch 100 may include a terrace 120 around the cup portion 110. The terrace 120 refers to the unmolded portion of the pouch film laminate, that is, the remaining area excluding the cup portion 110. The terrace 129 is a part that is sealed through thermal bonding in the process of accommodating the electrode assembly 200 in the cup portion 110, injecting electrolyte, and then sealing.
상기 컵부(110)는 바닥면 및 둘레면을 포함할 수 있다. 둘레면은 바닥면과 테라스(120)를 연결할 수 있다. 둘레면은 복수개, 좀 더 상세히는 4개가 구비될 수 있다. 바닥면은 전극 조립체(200)의 일면을 커버할 수 있고, 둘레면은 전극 조립체(200)의 둘레를 포위할 수 있다.The cup portion 110 may include a bottom surface and a peripheral surface. The peripheral surface may connect the floor surface and the terrace 120. There may be a plurality of circumferential surfaces, more specifically four. The bottom surface may cover one side of the electrode assembly 200, and the peripheral surface may surround the circumference of the electrode assembly 200.
한편, 상기 폴딩부(130)는 하부 케이스(101)와 상부 케이스(102)를 연결하고, 컵부(110)에 전극 조립체(200)를 수납하고, 전해액을 주입한 후에 접혀서 상부 케이스(102)가 하부 케이스(101)의 컵부(110)를 밀봉할 수 있게 한다. 폴딩부(130)을 포함될 경우, 하부 케이스(101)와 상부 케이스(102)가 일체로 연결되므로, 추후 실링 공정을 수행할 때, 실링할 사이드 개수가 감소하여 공정성이 향상되는 효과가 있다. Meanwhile, the folding part 130 connects the lower case 101 and the upper case 102, stores the electrode assembly 200 in the cup part 110, and folds after injecting the electrolyte to form the upper case 102. It is possible to seal the cup portion 110 of the lower case 101. When the folding part 130 is included, the lower case 101 and the upper case 102 are integrally connected, so when performing a sealing process later, the number of sides to be sealed is reduced, thereby improving fairness.
상기 폴딩부(130)은 컵부(110)와 이격되어 형성되며, 상기 폴딩부(130)와 컵부(110)의 이격 거리는 0.5mm 내지 3mm, 바람직하게는 0.5mm 내지 2mm 정도일 수 있다. 폴딩부(130)가 컵부(110)에 너무 가깝게 형성되면 폴딩이 원활하게 수행되지 않으며, 폴딩부(130)가 컵부(110)와 너무 멀게 형성되면 이차 전지의 전체 부피가 증가하여 부피 대비 에너지 밀도가 감소할 수 있다. 2컵 케이스의 경우, 상기 폴딩부는 각각의 컵부에 대해 상기 이격 거리를 만족하도록 형성될 수 있다. The folding part 130 is formed to be spaced apart from the cup part 110, and the separation distance between the folding part 130 and the cup part 110 may be about 0.5 mm to 3 mm, preferably about 0.5 mm to 2 mm. If the folding part 130 is formed too close to the cup part 110, folding is not performed smoothly, and if the folding part 130 is formed too far from the cup part 110, the total volume of the secondary battery increases and the energy density relative to volume increases. may decrease. In the case of a 2-cup case, the folding portion may be formed to satisfy the above-mentioned separation distance for each cup portion.
전극 조립체electrode assembly
전극 조립체(200)는, 교대로 적층된 복수개의 전극 및 복수개의 분리막을 포함할 수 있다. 복수개의 전극은 분리막을 사이에 두고 번갈아 적층되며 서로 반대 극성을 갖는 양극 및 음극을 포함할 수 있다.The electrode assembly 200 may include a plurality of electrodes and a plurality of separators that are alternately stacked. The plurality of electrodes are alternately stacked with a separator in between and may include an anode and a cathode having opposite polarities.
또한, 전극 조립체(200)에는 서로 용접된 복수개의 전극 탭(230)이 구비될 수 있다. 복수개의 전극 탭(230)은 복수개의 전극(210)에 연결될 수 있으며, 전극 조립체(200)로부터 외부로 돌출되어, 전극 조립체(200)의 내부와 외부 사이에 전자가 이동할 수 있는 통로로 작용할 수 있다. 복수개의 전극 탭(230)은 파우치(100)의 내부에 위치할 수 있다.Additionally, the electrode assembly 200 may be provided with a plurality of electrode tabs 230 welded to each other. The plurality of electrode tabs 230 may be connected to the plurality of electrodes 210 and may protrude outward from the electrode assembly 200 to act as a path through which electrons can move between the inside and outside of the electrode assembly 200. there is. A plurality of electrode tabs 230 may be located inside the pouch 100.
양극에 연결된 전극 탭(230)과 음극에 연결된 전극 탭(230)은 전극 조립체(200)에 대해 서로 다른 방향으로 돌출될 수 있다. 다만, 이에 한정되는 것은 아니며, 양극에 연결된 전극 탭(230)과 음극에 연결된 전극 탭(230)이 서로 나란하게 동일 방향으로 돌출되는 것도 가능하다.The electrode tab 230 connected to the anode and the electrode tab 230 connected to the cathode may protrude in different directions with respect to the electrode assembly 200. However, it is not limited to this, and it is possible for the electrode tab 230 connected to the anode and the electrode tab 230 connected to the cathode to protrude in the same direction and parallel to each other.
복수개의 전극 탭(230)에는 이차 전지의 외부로 전기를 공급하는 리드(240)가 스팟(Spot) 용접 등으로 연결될 수 있다. 리드(240)는 일단은 복수개의 전극 탭(230)과 연결되고 타단은 파우치(100)의 외부로 돌출될 수 있다. Leads 240 that supply electricity to the outside of the secondary battery may be connected to the plurality of electrode tabs 230 by spot welding or the like. One end of the lead 240 may be connected to the plurality of electrode tabs 230 and the other end may protrude to the outside of the pouch 100 .
리드(240)의 일부는 절연부(250)로 주위가 포위될 수 있다. 예를 들어, 절연부(250)는 절연 테이프를 포함할 수 있다. 상기 절연부(250)는 제1케이스(101)의 테라스(120)와 제2케이스(102)의 사이에 위치할 수 있고, 이러한 상태에서 테라스(120)와 제2케이스(102)는 서로 열 융착될 수 있다. 이 경우, 테라스(120) 및 제2케이스(102)의 일부는 절연부(250)와 열 융착될 수 있다. 따라서, 절연부(250)는 전극 조립체(200)로부터 생성되는 전기가 리드(240)를 통해 파우치(100)로 흐르는 것을 방지하며, 파우치(100)의 실링을 유지시킬 수 있다.A portion of the lead 240 may be surrounded by an insulating portion 250 . For example, the insulating portion 250 may include an insulating tape. The insulating portion 250 may be located between the terrace 120 of the first case 101 and the second case 102, and in this state, the terrace 120 and the second case 102 are opened to each other. can be fused. In this case, a portion of the terrace 120 and the second case 102 may be heat-sealed to the insulating portion 250. Accordingly, the insulating portion 250 prevents electricity generated from the electrode assembly 200 from flowing into the pouch 100 through the lead 240 and maintains the seal of the pouch 100.
한편, 본 발명에 있어서, 상기 전극 조립체(200)는 전폭 길이에 대한 전장 길이의 비가 5 내지 10, 바람직하게는 5 내지 8일 수 있다. 전폭에 대한 전장의 길이 비가 상기 범위를 만족할 경우, 한정된 공간에서 높은 에너지 밀도를 구현할 수 있다. Meanwhile, in the present invention, the electrode assembly 200 may have a ratio of the full length to the full width length of 5 to 10, preferably 5 to 8. When the ratio of total length to total width satisfies the above range, high energy density can be achieved in a limited space.
예를 들면, 상기 전극 조립체는 전장 길이가 400mm 내지 600mm이고, 전폭 길이가 50 내지 150mm, 바람직하게는 전장 길이가 500mm 내지 600mm이고, 전폭 길이가 50 내지 100mm일 수 있다.For example, the electrode assembly may have an overall length of 400 mm to 600 mm and an overall width of 50 to 150 mm, preferably 500 mm to 600 mm in overall length, and 50 to 100 mm in overall width.
한편, 이로써 한정되는 것은 아니나, 상기 전극 조립체의 무게는 500g 내지 1500g, 바람직하게는 550g 내지 1450g, 더 바람직하게는 600g 내지 1400g 일 수 있다. 전극 조립체의 무게가 상기 범위를 만족할 때, 고용량을 구현할 수 있으며, 전극 조립체와 전지 케이스 내면 간의 마찰력이 높아져 내충격성이 우수하게 나타날 수 있다.Meanwhile, although not limited thereto, the weight of the electrode assembly may be 500 g to 1500 g, preferably 550 g to 1450 g, and more preferably 600 g to 1400 g. When the weight of the electrode assembly satisfies the above range, high capacity can be realized, and the friction between the electrode assembly and the inner surface of the battery case increases, resulting in excellent impact resistance.
한편, 본 발명에 따른 이차 전지는, 필요에 따라, 상기 전극 조립체의 외면에 적어도 하나 이상의 고정 부재를 더 포함할 수 있다. 전장이 전폭에 비해 긴 직사각형 형태의 전극 조립체(편의상 '롱-셀(long-cell)'이라 함)의 경우, 전극 조립체의 구성 요소, 즉 양극, 음극 및 분리막의 정렬이 흐트러지지 않도록 하기 위해 전극 조립체를 전폭 방향으로 감아서 고정하는 고정 부재를 사용할 수 있다. Meanwhile, the secondary battery according to the present invention may further include at least one fixing member on the outer surface of the electrode assembly, if necessary. In the case of a rectangular electrode assembly (referred to as a 'long-cell' for convenience) whose full length is longer than the full width, the electrode assembly is used to prevent the alignment of the components of the electrode assembly, that is, the anode, cathode, and separator, from being disturbed. A fixing member that secures the assembly by wrapping it in the full width direction can be used.
상기 고정 부재는 다공성 구조를 포함하는 것일 수 있다. 고정 부재가 다공성 구조를 포함할 경우, 전해질이 고정 부재를 통과하여 전극 조립체 내부로 함침될 수 있어 고정 부재로 인해 전극 조립체의 전해질 함침성이 저하되는 것을 방지할 수 있다. 구체적으로는, 상기 고정 부재는 다공성 구조를 갖는 고분자 재질의 기재층의 일면에 접착층이 형성된 마감 테이프일 수 있으나, 이에 한정되는 것은 아니다. 상기 고분자 재질은, 예를 들면, 폴리에틸렌테레프탈레이트(PET), 폴리비닐클로라이드(PVC), 폴리에틸렌(PE) 등일 수 있으나, 이에 한정되는 것은 아니다.The fixing member may include a porous structure. When the fixing member includes a porous structure, the electrolyte can pass through the fixing member and be impregnated into the electrode assembly, thereby preventing the electrolyte impregnation of the electrode assembly from being deteriorated due to the fixing member. Specifically, the fixing member may be a finishing tape with an adhesive layer formed on one side of a polymer base layer having a porous structure, but is not limited thereto. The polymer material may be, for example, polyethylene terephthalate (PET), polyvinyl chloride (PVC), polyethylene (PE), etc., but is not limited thereto.
상기 고정 부재는 전극 조립체의 전폭 방향에 따른 너비가 10 ~ 50mm 또는 20 ~ 40mm 정도인 것이 바람직하다. 고정 부재의 너비가 너무 넓으면, 고정 부재에 의해 덮혀지는 전극 조립체의 외면 면적이 증가하여 전해질과의 접촉 면적이 감소하여 전해질 함침성이 저하될 수 있으며, 전극 조립체와 전지 케이스 간 마찰력이 감소하여 내충격성이 저하될 수 있다. 한편, 고정 부재의 너비가 너무 얇으면 전극 조립체 고정 효과가 저하될 수 있다.The fixing member preferably has a width of about 10 to 50 mm or 20 to 40 mm along the full width direction of the electrode assembly. If the width of the fixing member is too wide, the outer surface area of the electrode assembly covered by the fixing member increases and the contact area with the electrolyte decreases, which may reduce electrolyte impregnation and reduce the friction between the electrode assembly and the battery case. Impact resistance may decrease. On the other hand, if the width of the fixing member is too thin, the effect of fixing the electrode assembly may be reduced.
상기 이차 전지는 2 내지 10개, 바람직하게는 2 내지 8개, 더 바람직하게는 3개 내지 7개의 고정 부재를 포함할 수 있다. 이때 상기 고정 부재들은 전장 방향을 따라 좌우 대칭인 위치에 배치될 수 있으며, 바람직하게는, 상기 고정 부재들이 등 간격으로 이격 배치될 수 있다. 고정 부재들을 복수개 구비하고, 상기와 같이 배치할 경우, 전장 길이가 긴 롱-셀 구조의 전극 조립체를 견고하게 고정할 수 있다.The secondary battery may include 2 to 10 fixing members, preferably 2 to 8 fixing members, and more preferably 3 to 7 fixing members. At this time, the fixing members may be arranged in left and right symmetrical positions along the overall length direction, and preferably, the fixing members may be spaced apart at equal intervals. When a plurality of fixing members are provided and arranged as described above, an electrode assembly having a long-cell structure with a long overall length can be firmly fixed.
한편, 상기 고정 부재와 상기 전극 조립체의 접촉 면적은 상기 전극 조립체의 전체 표면적이 30% 이하, 25% 이하, 또는 20% 이하일 수 있다. 구체적으로는, 상기 고정 부재와 상기 전극 조립체가 접촉하는 면적은 상기 전극 조립체의 전체 표면적의 0 ~ 30%, 1 ~ 30%, 5 ~ 30%, 5 ~ 25% 또는 5 ~ 20%일 수 있다. Meanwhile, the contact area between the fixing member and the electrode assembly may be 30% or less, 25% or less, or 20% or less of the total surface area of the electrode assembly. Specifically, the contact area between the fixing member and the electrode assembly may be 0 to 30%, 1 to 30%, 5 to 30%, 5 to 25%, or 5 to 20% of the total surface area of the electrode assembly. .
상기 고정 부재와 전극 조립체의 접촉 면적은 사용되는 고정 부재의 폭 또는 사용되는 고정 부재의 개수를 조절하여 조절할 수 있다. 일반적으로 사용되는 고정 부재는 전극 조립체의 최외면에 배치되는 분리막에 비해 마찰 계수가 작은 재질로 이루어지기 때문에, 전극 조립체를 감싸는 고정 부재의 면적이 증가하면 전극 조립체와 전지 케이스 내면 간의 마찰력이 저하될 수 있다. 따라서, 고정 부재를 사용할 경우, 전극 조립체 간 접촉 면적을 30% 이하로 하여 마찰력 감소를 억제하는 것이 바람직하다.The contact area between the fixing member and the electrode assembly can be adjusted by adjusting the width of the fixing member used or the number of fixing members used. Since the commonly used fixing member is made of a material with a lower friction coefficient than the separator disposed on the outermost surface of the electrode assembly, if the area of the fixing member surrounding the electrode assembly increases, the friction between the electrode assembly and the inner surface of the battery case will decrease. You can. Therefore, when using a fixing member, it is desirable to suppress a decrease in friction force by setting the contact area between electrode assemblies to 30% or less.
전해질electrolyte
전해질은 이차 전지의 충, 방전 시 전극의 전기 화학적 반응에 의해 생성되는 리튬 이온을 이동시키기 위한 것으로, 유기 용매 및 리튬염을 포함할 수 있다. The electrolyte is used to move lithium ions generated by the electrochemical reaction of the electrode during charging and discharging of the secondary battery, and may include an organic solvent and a lithium salt.
상기 유기 용매로는 전지의 전기 화학적 반응에 관여하는 이온들이 이동할 수 있는 매질 역할을 할 수 있는 것이라면 특별한 제한없이 사용될 수 있다. 구체적으로 상기 유기 용매로는, 메틸 아세테이트(methyl acetate), 에틸 아세테이트(ethyl acetate), γ-부티로락톤(γ-butyrolactone), ε-카프로락톤(ε-caprolactone) 등의 에스테르계 용매; 디부틸 에테르(dibutyl ether) 또는 테트라히드로퓨란(tetrahydrofuran) 등의 에테르계 용매; 시클로헥사논(cyclohexanone) 등의 케톤계 용매; 벤젠(benzene), 플루오로벤젠(fluorobenzene) 등의 방향족 탄화수소계 용매; 디메틸카보네이트(dimethylcarbonate, DMC), 디에틸카보네이트(diethylcarbonate, DEC), 메틸에틸카보네이트(methylethylcarbonate, MEC), 에틸메틸카보네이트(ethylmethylcarbonate, EMC), 에틸렌카보네이트(ethylene carbonate, EC), 프로필렌카보네이트(propylene carbonate, PC) 등의 카보네이트계 용매; 에틸알코올, 이소프로필 알코올 등의 알코올계 용매; R-CN(R은 C2 내지 C20의 직쇄상, 분지상 또는 환 구조의 탄화수소기이며, 이중결합 방향 환 또는 에테르 결합을 포함할 수 있다) 등의 니트릴류; 디메틸포름아미드 등의 아미드류; 1,3-디옥솔란 등의 디옥솔란류; 또는 설포란(sulfolane)류 등이 사용될 수 있다. 이중에서도 카보네이트계 용매가 바람직하고, 전지의 충방전 성능을 높일 수 있는 높은 이온전도도 및 고유전율을 갖는 환형 카보네이트(예를 들면, 에틸렌카보네이트 또는 프로필렌카보네이트 등)와, 저점도의 선형 카보네이트계 화합물(예를 들면, 에틸메틸카보네이트, 디메틸카보네이트 또는 디에틸카보네이트 등)의 혼합물이 보다 바람직하다. The organic solvent may be used without particular limitation as long as it can serve as a medium through which ions involved in the electrochemical reaction of the battery can move. Specifically, the organic solvent includes ester solvents such as methyl acetate, ethyl acetate, γ-butyrolactone, and ε-caprolactone; Ether-based solvents such as dibutyl ether or tetrahydrofuran; Ketone-based solvents such as cyclohexanone; Aromatic hydrocarbon solvents such as benzene and fluorobenzene; Dimethylcarbonate (DMC), diethylcarbonate (DEC), methylethylcarbonate (MEC), ethylmethylcarbonate (EMC), ethylene carbonate (EC), propylene carbonate Carbonate-based solvents such as PC); Alcohol-based solvents such as ethyl alcohol and isopropyl alcohol; nitriles such as R-CN (R is a C2 to C20 straight-chain, branched or ring-structured hydrocarbon group and may include a double bond aromatic ring or ether bond); Amides such as dimethylformamide; Dioxolanes such as 1,3-dioxolane; Alternatively, sulfolane, etc. may be used. Among these, carbonate-based solvents are preferable, and cyclic carbonates (e.g., ethylene carbonate or propylene carbonate, etc.) with high ionic conductivity and high dielectric constant that can improve the charge/discharge performance of the battery, and low-viscosity linear carbonate-based compounds ( For example, ethylmethyl carbonate, dimethyl carbonate, diethyl carbonate, etc.) are more preferable.
상기 리튬염은 리튬 이차전지에서 사용되는 리튬 이온을 제공할 수 있는 화합물이라면 특별한 제한 없이 사용될 수 있다. 구체적으로 상기 리튬염은, LiPF6, LiClO4, LiAsF6, LiBF4, LiSbF6, LiAl04, LiAlCl4, LiCF3SO3, LiC4F9SO3, LiN(C2F5SO3)2, LiN(C2F5SO2)2, LiN(CF3SO2)2. LiCl, LiI, 또는 LiB(C2O4)2 등이 사용될 수 있다. 상기 리튬염의 농도는 0.1 내지 5.0M, 바람직하게는 0.1 내지 3,0M 범위 내에서 사용하는 것이 좋다. 리튬염의 농도가 상기 범위에 포함되면, 전해질이 적절한 전도도 및 점도를 가지므로 우수한 전해질 성능을 나타낼 수 있고, 리튬 이온이 효과적으로 이동할 수 있다.The lithium salt can be used without particular limitations as long as it is a compound that can provide lithium ions used in lithium secondary batteries. Specifically, the lithium salt is LiPF 6 , LiClO 4 , LiAsF 6 , LiBF 4 , LiSbF 6 , LiAl0 4 , LiAlCl 4 , LiCF 3 SO 3 , LiC 4 F 9 SO 3 , LiN(C 2 F 5 SO 3 ) 2 , LiN(C 2 F 5 SO 2 ) 2 , LiN(CF 3 SO 2 ) 2 . LiCl, LiI, or LiB(C 2 O 4 ) 2 may be used. The concentration of the lithium salt is preferably used within the range of 0.1 to 5.0M, preferably 0.1 to 3.0M. When the concentration of lithium salt is within the above range, the electrolyte has appropriate conductivity and viscosity, so excellent electrolyte performance can be achieved and lithium ions can move effectively.
상기 전해질에는 상기 전해질 구성 성분들 외에도 전지의 수명 특성 향상, 전지 용량 감소 억제, 전지의 방전 용량 향상 등을 목적으로 첨가제를 추가로 포함할 수 있다. In addition to the electrolyte components, the electrolyte may further include additives for the purpose of improving battery life characteristics, suppressing battery capacity reduction, and improving battery discharge capacity.
이하, 구체적인 실시예를 통해 본 발명을 보다 자세히 설명한다.Hereinafter, the present invention will be described in more detail through specific examples.
실시예 1Example 1
나일론/폴리에틸렌테레프탈레이트/Al 합금 박막/폴리프로필렌이 순차적으로 적층되고, 컵부가 성형된 파우치를 준비하였다. 상기 컵부에 전장 548mm, 전폭 99mm, 무게 1380g의 스택형 전극 조립체를 수납한 후, 전해액을 주입한 다음 실링하고, 활성화 공정을 수행하여 파우치형 이차 전지를 제조하였다. 이때, 상기 전해액은 활성화 공정 이후에 단위 용량당 잔존 전해액 양이 2.2g/Ah가 되도록 주입하였다. A pouch in which nylon/polyethylene terephthalate/Al alloy thin film/polypropylene were sequentially laminated and the cup portion was molded was prepared. After storing the stacked electrode assembly with a total length of 548 mm, a total width of 99 mm, and a weight of 1380 g in the cup part, an electrolyte solution was injected, sealing was performed, and an activation process was performed to manufacture a pouch-type secondary battery. At this time, the electrolyte was injected so that the amount of remaining electrolyte per unit capacity was 2.2 g/Ah after the activation process.
실시예 2Example 2
활성화 공정 이후에 단위용량 당 잔존 전해액 양이 2.15g/Ah가 되도록 전해액을 주입한 점을 제외하고는, 실시예 1과 동일한 방법으로 파우치형 이차 전지를 제조하였다. A pouch-type secondary battery was manufactured in the same manner as Example 1, except that the electrolyte was injected so that the amount of remaining electrolyte per unit capacity was 2.15 g/Ah after the activation process.
실시예 3Example 3
전장 548mm, 전폭 78mm, 무게 641g의 스택형 전극 조립체를 사용하였으며, 활성화 공정 이후에 단위 용량 당 잔존 전해액 양이 1.7g/Ah가 되도록 전해액을 주입한 점을 제외하고는, 실시예 1과 동일한 방법으로 파우치형 이차 전지를 제조하였다. A stacked electrode assembly with a total length of 548 mm, a total width of 78 mm, and a weight of 641 g was used, and the same method as Example 1 was used, except that the electrolyte solution was injected so that the amount of remaining electrolyte per unit capacity was 1.7 g/Ah after the activation process. A pouch-type secondary battery was manufactured.
비교예 1Comparative Example 1
전장 548mm, 전폭 78mm, 무게 641g의 스택형 전극 조립체를 사용하였으며, 활성화 공정 이후에 단위 용량 당 잔존 전해액 양이 2.2g/Ah가 되도록 전해액을 주입한 점을 제외하고는, 실시예 1과 동일한 방법으로 파우치형 이차 전지를 제조하였다. A stacked electrode assembly with a total length of 548 mm, a total width of 78 mm, and a weight of 641 g was used, and the same method as Example 1 was used, except that the electrolyte solution was injected so that the amount of remaining electrolyte per unit capacity was 2.2 g / Ah after the activation process. A pouch-type secondary battery was manufactured.
비교예 2Comparative Example 2
활성화 공정 이후에 단위 용량 당 잔존 전해액 양이 2.3g/Ah가 되도록 전해액을 주입한 점을 제외하고는, 실시예 1과 동일한 방법으로 파우치형 이차 전지를 제조하였다. A pouch-type secondary battery was manufactured in the same manner as Example 1, except that the electrolyte was injected so that the amount of remaining electrolyte per unit capacity was 2.3 g/Ah after the activation process.
실험예 1: 마찰력 평가Experimental Example 1: Friction force evaluation
실시예 1 ~ 3 및 비교예 1 ~ 2에서 제조된 파우치형 이차 전지에 있어서, 파우치 컵부 내면과 전극 조립체 사이의 마찰력을 하기 방법으로 측정하였다. In the pouch-type secondary batteries manufactured in Examples 1 to 3 and Comparative Examples 1 to 2, the frictional force between the inner surface of the pouch cup portion and the electrode assembly was measured by the following method.
이차 전지의 파우치 일부를 절개하고, 와이어가 연결된 지그로 양극 탭을 잡은 다음, 만능재료시험기(UTM)에 상기 와이어를 연결한 후, 100mm/min의 속도로 잡아당기면서 걸리는 힘(Force)을 측정하고, 상기 침을 전극 조립체와 컵부 바닥면 사이의 마찰력으로 평가하였다. Cut a portion of the pouch of the secondary battery, hold the positive tab with a jig with a wire attached, connect the wire to a universal testing machine (UTM), and measure the force while pulling at a speed of 100 mm/min. And the needle was evaluated by the friction force between the electrode assembly and the bottom surface of the cup.
측정 결과는 하기 표 1에 나타내었다. The measurement results are shown in Table 1 below.
실험예 2: 충돌 쇼크 테스트Experimental Example 2: Crash shock test
실시예 1 ~ 3 및 비교예 1 ~ 2에서 제조된 파우치형 이차 전지에 대하여 133.7G X 15.8ms 충돌 조건으로 충돌 쇼크 테스트(crash shock test)을 실시하였다. 측정 결과는 하기 표 1에 나타내었다. 테스트 후에 전해액 누설 및 전극 조립체 이탈이 발생하지 않은 경우에는 Pass로, 전해액 누설 및/또는 전극 조립체 이탈이 발생한 경우에는 Fail로 표시하였다.A crash shock test was performed on the pouch-type secondary batteries manufactured in Examples 1 to 3 and Comparative Examples 1 to 2 under crash conditions of 133.7G x 15.8ms. The measurement results are shown in Table 1 below. If electrolyte leakage and electrode assembly separation did not occur after the test, it was marked as Pass, and if electrolyte leakage and/or electrode assembly separation occurred, it was marked as Fail.
구분division 전장
[m]Battlefield
[m] 		전폭
[m]full width
[m] 		단위용량당 전해액 잔존량
[g/Ah]Remaining amount of electrolyte per unit capacity
[g/Ah] 		W/S
[(g/Ah)·m-²]W/S
[(g/Ah)·m-²] 		마찰력
[kgf]friction force
[kgf] 		충돌 쇼크 테스트 결과Crash shock test results
실시예1Example 1 0.5480.548 0.0990.099 2.22.2 40.640.6 17.517.5 PassPass
실시예2Example 2 0.5480.548 0.0990.099 2.152.15 39.239.2 20.620.6 PassPass
실시예3Example 3 0.5480.548 0.0780.078 1.71.7 39.839.8 32.432.4 PassPass
비교예1Comparative Example 1 0.5480.548 0.0780.078 2.22.2 51.551.5 11.611.6 FailFail
비교예2Comparative example 2 0.5480.548 0.0990.099 2.32.3 42.442.4 11.411.4 FailFail
상기 [표 1]에 나타난 바와 같이, W/S가 42(g/Ah)·m-² 미만인 실시예 1 ~ 3의 전지의 경우, 전극 조립체와 파우치 내면 사이의 마찰력이 15kgf 이상으로 높게 나타났으며, 이로 인해 외부 충격으로 인한 전극 조립체의 이탈이 억제되어 우수한 내충격성을 나타내었다. 이에 반해, W/S가 42(g/Ah)·m-²를 초과하는 비교에 1 및 2의 경우, 마찰력이 현저하게 감소하였으며, 그 결과 충격 테스트 시에 전해액 누설이 발생하였다. As shown in [Table 1], in the case of the batteries of Examples 1 to 3 with W/S of less than 42 (g/Ah)·m - ², the friction force between the electrode assembly and the inner surface of the pouch was found to be as high as 15 kgf or more. As a result, separation of the electrode assembly due to external impact was suppressed, showing excellent impact resistance. On the other hand, in cases 1 and 2 where W/S exceeded 42(g/Ah)·m - ², the friction force was significantly reduced, and as a result, electrolyte leakage occurred during the impact test.

Claims (15)

  1. 전극 조립체;electrode assembly;
    전해질; 및electrolyte; and
    상기 전극 조립체 및 상기 전해질을 수용하기 위한 수용부를 포함하는 전지 케이스;를 포함하고, It includes a battery case including a receiving portion for accommodating the electrode assembly and the electrolyte,
    상기 전극 조립체, 상기 전해질 및 상기 전지 케이스는 하기 식 (1)을 만족하도록 구성된 이차 전지.A secondary battery in which the electrode assembly, the electrolyte, and the battery case are configured to satisfy the following equation (1).
    식 (1): W / S ≤ 42(g/Ah)·m-²Equation (1): W / S ≤ 42(g/Ah)·m - ²
    상기 식 (1)에서, W는 상기 이차 전지의 단위 용량 당 전해액 중량[단위: g/Ah]이며, 상기 S는 상기 전극 조립체의 전장[단위: m]과 전폭[단위: m]의 곱이다. In equation (1), W is the weight of electrolyte per unit capacity of the secondary battery [unit: g/Ah], and S is the product of the overall length [unit: m] and the overall width [unit: m] of the electrode assembly. .
  2. 제1항에 있어서, According to paragraph 1,
    상기 전지 케이스는 배리어층, 상기 배리어층 일면에 형성되는 기재층, 및 상기 배리어층의 타면에 형성되는 실런트층을 포함하며, The battery case includes a barrier layer, a base layer formed on one side of the barrier layer, and a sealant layer formed on the other side of the barrier layer,
    일 방향으로 만곡된 적어도 하나 이상의 컵부를 포함하는 파우치이고,It is a pouch including at least one cup portion curved in one direction,
    상기 적어도 하나 이상의 컵부에 전극 조립체 및 전해질이 수용되는 것인 이차 전지.A secondary battery in which an electrode assembly and an electrolyte are accommodated in the at least one cup portion.
  3. 제1항 또는 제2항에 있어서.According to paragraph 1 or 2.
    상기 W/S가 30(g/Ah)·m-² 내지 42(g/Ah)·m-²인 이차 전지.A secondary battery having the W/S of 30(g/Ah)·m - ² to 42(g/Ah)·m - ².
  4. 제1항 또는 제2항에 있어서.According to paragraph 1 or 2.
    상기 식(1)의 W가 2.2 g/Ah 이하인 이차 전지.A secondary battery in which W in the above formula (1) is 2.2 g/Ah or less.
  5. 제1항 또는 제2항에 있어서.According to paragraph 1 or 2.
    상기 식(1)의 W가 1.5 g/Ah 내지 2.2 g/Ah 인 이차 전지.A secondary battery in which W of formula (1) is 1.5 g/Ah to 2.2 g/Ah.
  6. 제1항 또는 제2항에 있어서.According to paragraph 1 or 2.
    상기 식 (1)의 S가 0.02 내지 0.09m2인 이차 전지.A secondary battery in which S in the above formula (1) is 0.02 to 0.09 m 2 .
  7. 제1항 또는 제2항에 있어서,According to claim 1 or 2,
    상기 전극 조립체는 전폭에 대한 전장의 비가 5 내지 10인 이차 전지.The electrode assembly is a secondary battery having a ratio of full length to full width of 5 to 10.
  8. 제1항 또는 제2항에 있어서, According to claim 1 or 2,
    상기 전극 조립체는 전장 길이가 400mm 내지 600mm이고, 전폭 길이가 50 내지 150mm인 이차 전지.The electrode assembly is a secondary battery having an overall length of 400 mm to 600 mm and an overall width of 50 to 150 mm.
  9. 제1항에 있어서,According to paragraph 1,
    상기 전극 조립체와 상기 전지 케이스의 내면 사이의 마찰력이 15kgf 이상인 이차 전지.A secondary battery in which friction between the electrode assembly and the inner surface of the battery case is 15 kgf or more.
  10. 제1항 또는 제2항에 있어서,According to claim 1 or 2,
    상기 이차 전지는 정격 용량이 50Ah 내지 200Ah인 파우치형 이차 전지. The secondary battery is a pouch-type secondary battery with a rated capacity of 50Ah to 200Ah.
  11. 제1항 또는 제2항에 있어서, According to claim 1 or 2,
    상기 이차 전지는, 133.7G×15.8ms 충돌 조건으로 충돌 쇼크 테스트(crash shock test)을 실시하였을 때, 전해액 누설량이 0인 이차 전지.The secondary battery is a secondary battery whose electrolyte leakage amount is 0 when a crash shock test is performed under 133.7G×15.8ms impact conditions.
  12. 제1항에 있어서,According to paragraph 1,
    상기 전극 조립체의 외면에 상기 전극 조립체를 전폭 방향으로 감아서 고정하는 적어도 하나 이상의 고정 부재를 더 포함하는 이차 전지.A secondary battery further comprising at least one fixing member fixed to an outer surface of the electrode assembly by wrapping the electrode assembly in the full width direction.
  13. 제12항에 있어서, According to clause 12,
    상기 고정 부재와 상기 전극 조립체의 접촉 면적이 상기 전극 조립체의 전체 표면적의 30% 이하인 이차 전지.A secondary battery wherein a contact area between the fixing member and the electrode assembly is 30% or less of the total surface area of the electrode assembly.
  14. 제1항에 있어서,According to paragraph 1,
    상기 전극 조립체는 무게가 500g 내지 1500g인 이차 전지.The electrode assembly is a secondary battery weighing 500g to 1500g.
  15. 전극 조립체; 전해액; 및 상기 전극 조립체 및 전해질이 수용되는 전지 케이스를 포함하는 이차 전지이며,electrode assembly; electrolyte; And a secondary battery including a battery case in which the electrode assembly and the electrolyte are accommodated,
    상기 전극 조립체는 평면상 표면적이 0.01 내지 0.2m2이고, The electrode assembly has a planar surface area of 0.01 to 0.2 m 2 ,
    상기 전해액의 총 중량이 440g 이하이며, The total weight of the electrolyte is 440 g or less,
    상기 전극 조립체, 전해액 및 전지 케이스가 상기 전극 조립체와 상기 전지 케이스 내면과의 마찰력이 15kgf 이상이 되도록 구성된 이차 전지.A secondary battery in which the electrode assembly, electrolyte, and battery case are configured such that a frictional force between the electrode assembly and the inner surface of the battery case is 15 kgf or more.
PCT/KR2023/015867 2022-10-14 2023-10-13 Secondary battery WO2024080837A1 (en)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100874385B1 (en) * 2006-07-10 2008-12-18 주식회사 엘지화학 Secondary battery safety member
KR101300111B1 (en) * 2011-08-31 2013-08-30 주식회사 엘지화학 Secondary battery having improved reliability for humidity penetration thereto
CN109952664A (en) * 2016-10-26 2019-06-28 大日本印刷株式会社 Battery use packing material, its manufacturing method, battery and its manufacturing method
KR20190142246A (en) * 2018-06-15 2019-12-26 스미또모 가가꾸 가부시키가이샤 Nonaqueous electrolyte secondary battery porous layer
KR20220047107A (en) * 2020-10-08 2022-04-15 주식회사 엘지에너지솔루션 Pouch-type battery with improved fixability

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100874385B1 (en) * 2006-07-10 2008-12-18 주식회사 엘지화학 Secondary battery safety member
KR101300111B1 (en) * 2011-08-31 2013-08-30 주식회사 엘지화학 Secondary battery having improved reliability for humidity penetration thereto
CN109952664A (en) * 2016-10-26 2019-06-28 大日本印刷株式会社 Battery use packing material, its manufacturing method, battery and its manufacturing method
KR20190142246A (en) * 2018-06-15 2019-12-26 스미또모 가가꾸 가부시키가이샤 Nonaqueous electrolyte secondary battery porous layer
KR20220047107A (en) * 2020-10-08 2022-04-15 주식회사 엘지에너지솔루션 Pouch-type battery with improved fixability

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