Electrode assembly three-dimensional

Abstract

To provide an electrode assembly with increased density of electrodes so as to have increased energy density.SOLUTION: An electrode assembly includes a plurality of electrodes aligned in stacks along a lamination axis. Each of the electrodes in the stack is separated, along the lamination axis, from continuous ones of the electrodes in the stack by a portion of a separator located between the electrodes. An outer surface of at least one of the stacks may include a pattern which defines a first region and a second region. Here, a second portion of the stack corresponding to the second region has characteristics or a height different from that of a first portion of the stack corresponding to the first region. The characteristics may include either of the following: a shade or a hue of at least one of outer surfaces of a laminate; air permeability of a separation membrane part in the first and second regions; and adhesive strength between the electrodes and the separation membrane part in the first and second regions.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] This application claims the benefit of the filing dates of Korean Patent Application No. 10-2021-0090592, Korean Patent Application No. 10-2021-0090588, and Korean Patent Application No. 10-2021-0090589, all of which are incorporated herein by reference.

[0002] This invention relates to an electrode assembly. Specifically, this invention relates to an electrode assembly for a secondary battery. [Background technology]

[0003] Unlike primary batteries, rechargeable batteries are rechargeable and have the potential for miniaturization and increased capacity, leading to extensive research and development in recent years. As technological development and demand for mobile devices increase, the demand for rechargeable batteries as an energy source is rapidly growing.

[0004] Rechargeable batteries are classified into coin-type batteries, cylindrical batteries, prismatic batteries, and pouch-type batteries according to the shape of their battery cases. The electrode assembly installed inside the battery case of a rechargeable battery is a power generation element capable of charging and discharging, consisting of a laminated structure of electrodes and a separator membrane.

[0005] Electrode assemblies can be classified into jelly-roll type, stack type, and stack-and-fold type. In the jelly-roll type, a separation membrane is interposed between sheet-shaped anodes and sheet-shaped cathodes, each coated with an active material, and the entire arrangement is wound up. In the stack type, multiple anodes and cathodes are sequentially stacked with a separation membrane in between. In the stack-and-fold type, the stacked unit cells can be wound onto a long-length separation film.

[0006] In the manufacturing process of conventional stack-and-fold electrode assemblies, the electrodes and separator membranes stacked on the electrode assembly are bonded together so that the finished stack can be carried as a unit without collapsing (for example, to move into the inside of a battery case). Such bonding can be achieved by heating and pressurizing the assembled stack. However, in the manufacturing process of conventional electrode assemblies, a problem has arisen in that the electrodes within the stack become distorted or twisted during this heating and pressurizing process.

[0007] To address the problems of conventional technologies, new levels were added to the laminate, and then heat and pressure were applied to the laminate, causing the electrodes and separators to bond to each other during the lamination process. However, this presents a problem: the adhesive force between the electrodes and separators dissipates significantly along the lamination direction due to the accumulation of heat and pressure in the lowest components of the laminate each time new heat and pressure are applied, while the upper components of the laminate have a relatively much lower adhesive force. This non-uniformity along the lamination direction can adversely affect the electrode assembly. For example, the lowest separator (where the most heat and pressure are accumulated) may have reduced porosity and decreased performance, while the upper separators may bond relatively weakly to adjacent electrodes. [Overview of the project] [Problems that the invention aims to solve]

[0008] This invention , complete The resulting electrode assembly can exhibit improved stability and uniformity. 。 [Means for solving the problem]

[0009] One embodiment of the present invention provides an electrode assembly. The electrode assembly according to one embodiment of the present invention includes a plurality of electrodes arranged in a laminate along a stacking axis, and each electrode in the laminate is separated from one of the electrodes in the laminate by each separator located therebetween along the stacking axis. At least one outer surface of the laminate includes a pattern composed of a first region and a second region, and a second portion of the laminate corresponding to the second region has different characteristics or heights from a first portion of the laminate corresponding to the first region, providing an electrode assembly.

[0010] In one embodiment of the present invention, a second portion of the laminate corresponding to the second region has different characteristics from a first portion of the laminate corresponding to the first region, and the characteristics include any one of a shadow of at least one outer surface of the laminate, a hue, air permeability of a separator portion between the first region and the second region, and an adhesive force between an electrode in the first region and the second region and a separator portion, providing an electrode assembly.

[0011] In one embodiment of the present invention, the separator is provided with an extended separator sheet, and the extended separator sheet is folded between the respective separators so as to extend between the respective electrodes continuous along the stacking axis along a winding path that traverses back and forth along a lateral direction perpendicular to the stacking axis. Each electrode in the laminate includes a first side end portion and a second side end portion on opposite side surfaces of the respective electrodes in the lateral direction, providing an electrode assembly.

Advantages of the Invention

[0012] According to the electrode assembly according to one embodiment of the present invention, A uniform adhesive force can be ensured for the electrode assembly. .

Brief Description of the Drawings

[0014] [Figure 1] It is a cross-sectional view showing an electrode assembly according to one embodiment of the present invention. [Figure 2] It is a cross-sectional view of the electrode assembly of FIG. 1, showing the positions of the upper surface, the lower surface and the middle portion of the electrode assembly. [Figure 3] It is a perspective view conceptually showing a stacked view of components of an electrode assembly according to an embodiment of the present invention. [Figure 4] It is a top view showing an electrode assembly including a first region and a second region according to an embodiment of the present invention. [Figure 5] It is a perspective view showing an electrode assembly including a first region and a second region according to another embodiment of the present invention. [Figure 6] (a) of FIG. 6 is a perspective view showing a first pressing part according to an embodiment of the present invention, and (b) of FIG. 6 is a perspective view showing a second pressing part according to an embodiment of the present invention.

Explanation of Reference Signs

[0015] S ··· laminate O ··· opening P ··· folding part 10 ··· electrode assembly 1 ··· first electrode 2 ··· second electrode 4 ··· first separator 4a ··· laminated part 4b ··· folding part 5 ··· second separator 6 ··· side end 50 ··· first pressing part 50a, 50b ··· first pressing block 51 ··· gripper 51a ··· body 51b ··· fixing part 60 ··· second pressing part 60a, 60b ··· second pressing block

Modes for Carrying Out the Invention

[0016] The detailed description of the present invention is intended to fully explain the invention to a person with ordinary skill in the art. Whereever in this specification a part of the description "includes" a component or a part of a structure and shape "characterizes", this means that, unless otherwise stated, other components, structures and shapes may be included, rather than excluding or excluding other components or structures and shapes.

[0017] Since the present invention may be subject to various transformations and may have various embodiments, we will present specific embodiments and explain them in detail in the detailed description. However, this is not intended to limit the scope of the invention by embodiments, but should be understood to include all transformations, equivalents, or substitutions that fall within the spirit and technical scope of the present invention.

[0018] The present invention will be described in detail below with reference to the drawings. However, the drawings are for illustrative purposes only, and the scope of the present invention is not limited by the drawings.

[0019] Figure 1 is a cross-sectional view showing an electrode assembly 10 according to one embodiment of the present invention, and Figure 3 is a perspective view showing electrodes 1 and 2 and a separation membrane 4 laminated on a laminate S of the electrode assembly 10 according to one embodiment of the present invention.

[0020] The electrode assembly 10 according to the present invention is a rechargeable power generation device and may include a stack S in which electrodes are arranged between portions of an extended separator membrane 4 that are folded in a zigzag shape along the stacking direction Y between each electrode. In this case, the electrodes may include one or more first electrodes 1 and one or more second electrodes 2 alternating along the stacking direction Y.

[0021] The curved shape of the separation membrane 4 along the stacking direction Y can be defined by continuous folding portions P of the separation membrane 4, each folding portion P of the separation membrane 4 can wrap around the lateral end 6 of an electrode in the lateral direction (Z, perpendicular to the stacking direction Y) before the separation membrane 4 extends to the opposing side of the stack S and passes between the electrode and the next adjacent electrode in the stack S. The portion of the separation membrane 4 extending from between each electrode of the stack S may be referred to as the stack portion of the separation membrane 4. Thus, each layer of the stack S (defined by the position of each electrode along the stack S) can be characterized by folding portions P of the separation membrane 4 that surround the lateral end 6 of an electrode on one side of the electrode from the lateral direction Z. The opposite side of the electrode along the lateral direction Z may be defined by an opening O featuring a component of the separation membrane 4 (including the folding portion P). Thus, the folding portions P may be alternately located on the opposing side of the stack S with respect to each continuous layer of the stack, such as the opening O on the opposite side of the stack S.

[0022] As will be further discussed herein, the “upper surface” of the electrode assembly 10, referred to as reference number 12 in Figure 2, can refer to the uppermost position of the electrode assembly 10 from the stacking direction of the electrode assembly. Furthermore, as mentioned herein, the “lower surface” of the electrode assembly 10, referred to as reference number 13 in Figure 2, can mean the lowest end position of the electrode assembly 10 from the stacking direction of the electrode assembly. Finally, as discussed herein, the “intermediate” of the electrode assembly 10, referred to as reference number 11 in Figure 2, means an intermediate position between the upper and lower surfaces of the electrode assembly 10 from the stacking direction of the electrode assembly 10. For example, if the electrode assembly 10 consists of nine electrodes and is viewed from the side, the “intermediate” position, as shown in Figure 2, relates to the position of the fifth electrode in the stack S. Thus, subsequent references to “intermediate air permeability” relate to the air permeability of the separation membrane 4 in contact with the intermediate electrode in the electrode assembly. Similarly, subsequent references to "intermediate adhesion" refer to the adhesion between the intermediate electrode of the electrode assembly and the adjacent portion of the separation membrane 4.

[0023] As previously discussed, the electrode assembly 10 may be provided in a form in which its outer casing is surrounded by an external separation membrane 5, which may be a part (e.g., an end portion) of the same extending separation membrane 4 along a zigzag or winding path along the separation membrane S. In one example, the outer periphery of the electrode assembly 10 surrounded by the external separation membrane 5 includes not only an upper and lower surface in the stacking direction Y, but also at least a pair of opposing sides in the lateral direction Z. Here, the upper surface of the stacked material S means the outer surface that forms the upper side of the stacked material S in the stacking direction Y, and the lower surface may mean the outer surface that forms the lower side opposite to the upper side of the stacked material S.

[0024] In one embodiment, the anode may be manufactured by coating an anode current collector with an anode coating mixture comprising, for example, an anode active material, a conductive material, and a binder, and then drying the coating mixture. A filler may be added to the mixture as needed. Such materials may be any suitable materials used in the relevant field, in particular materials commonly used in a specific application field.

[0025] Specifically, the anode active material is, for example, a layered compound such as lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), or a compound substituted with one or more transition metals; chemical formula Li 1+x Mn 2-x Lithium manganese oxides such as O4 (where x is 0 to 0.33), LiMnO3, LiMn2O3, LiMnO2; lithium copper oxide (Li2CuO2); vanadium oxides such as LiV3O8, LiFe3O4, V2O5, Cu2V2O7; chemical formula LiNi 1-x M x Ni-site type lithium nickel oxide represented as O2 (where M = Co, Mn, Al, Cu, Fe, Mg, B, or Ga, and x = 0.01 to 0.3); chemical formula LiMn 2-x M xLithium manganese composite oxides represented as O2 (where M = Co, Ni, Fe, Cr, Zn, or Ta, and x = 0.01 to 0.1) or Li2Mn3MO8 (where M = Fe, Co, Ni, Cu, or Zn); LiMn2O4 in which part of the Li in the chemical formula is substituted with alkaline earth metal ions; disulfide compounds; Fe2(MoO4)3, etc., are examples, but are not limited to these.

[0026] The material that can be used for the anode current collector is not particularly limited. Preferably, the anode current collector has relatively high conductivity without causing chemical changes when used in a battery. For example, stainless steel, aluminum, nickel, titanium, calcined carbon, or aluminum or stainless steel with a surface treatment of carbon, nickel, titanium, silver, etc. may be used. Preferably, the anode current collector may be aluminum. Preferably, the adhesion between the current collector and the anode coating mixture can be increased by including fine irregularities on the surface of the current collector that comes into contact with the coating mixture. Furthermore, various forms such as film, sheet, foil, net, porous material, foam, and nonwoven fabric are possible. The anode current collector may generally have a thickness of 3 μm to 500 μm. The conductive material contained in the anode coating mixture may generally be present in an amount of 1 to 50% by weight of the total weight of the mixture containing the anode active material. For example, graphite such as natural graphite or artificial graphite; carbon black such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, and summer black; conductive fibers such as carbon fibers and metal fibers; metal powders such as carbon fluoride, aluminum, and nickel powder; conductive whiskey such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; and conductive materials such as polyphenylene derivatives may be used.

[0027] The binder of the anode coating mixture is a component that aids in binding the active material and the conductive material and binding to the current collector of the coating mixture. Such a binder may generally be included in an amount of 1 to 50% by weight of the total weight of the mixture containing the anode active material. Examples of such binders include polyvinylidene fluoride, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene-butadiene rubber, fluorine rubber, various copolymers, and the like. The filler optionally added to the anode coating mixture may be used as a component to suppress the expansion of the anode. Such fillers are not particularly limited and may include fibrous substances that do not cause chemical changes when used in the battery. For example, olefin polymers such as polyethylene and polypropylene; fibrous substances such as glass fibers and carbon fibers are used.

[0028] In one embodiment, the cathode may be manufactured by applying, drying, and pressing the cathode active material onto the cathode current collector, and optionally, conductive materials, binders, fillers, etc. as described above may be further selectively included. In this case as well, substances commonly used in the art may be used. Specifically, the cathode active material is, for example, carbon such as graphitizable carbon and graphite-based carbon; Li x Fe2O3 (0≦x≦1), Li x WO2 (0≦x≦1), Sn x Me 1-x Me' y O z(Me: Mn, Fe, Pb, Ge; Me': Al, B, P, Si, Group 1, Group 2, Group 3 elements of the periodic table, halogen; 0 < x ≤ 1; 1 ≤ y ≤ 3; 1 ≤ z ≤ 8), etc. metal composite oxides; lithium metal; lithium alloys; silicon-based alloys; tin-based alloys; metal oxides such as SnO, SnO2, PbO, PbO2, Pb2O3, Pb3O4, Sb2O3, Sb2O4, Sb2O5, GeO, GeO2, Bi2O3, Bi2O4, and Bi2O5; conductive polymers such as polyacetylene; Li-Co-Ni-based materials, etc. may be used.

[0029] The material that can be used for the cathode current collector is not particularly limited. The cathode current collector preferably does not cause chemical changes when used in a battery and has a relatively high conductivity. For example, copper, stainless steel, aluminum, nickel, titanium, fired carbon, those surface-treated with carbon, nickel, titanium, silver, etc. on the surface of copper or stainless steel, aluminum-cadmium alloys, etc. can be used. Also, similar to the anode current collector, fine irregularities can be formed on the surface to strengthen the binding force of the cathode active material. It may be used in various forms such as films, sheets, foils, nets, porous bodies, foams, non-woven bodies, etc. Furthermore, the cathode current collector may generally have a thickness of 3 μm to 500 μm.

[0030] In one embodiment of the present invention, the separation membrane may be an organic / inorganic composite porous SRS (Safety-Reinforcing Separators) separation membrane. The SRS separation membrane may have a structure in which a coating layer component containing inorganic particles and a binder polymer is applied on a polyolefin-based separation membrane substrate.

[0031] Such an SRS separation membrane does not cause high-temperature thermal shrinkage due to the heat resistance of the inorganic particles, so even if the electrode assembly penetrates through a needle-shaped conductor, the elongation rate of the safety separation membrane can be maintained.

[0032] Such an SRS separation membrane may have a uniform pore structure formed by the interstitial volume (spaces between inorganic particles that make up the coating layer) as well as the pore structure contained in the separation membrane substrate itself. These pores can not only considerably mitigate external shocks applied to the electrode assembly, but also allow for the smooth movement of lithium ions through the pores, enabling the filling of a large amount of electrolyte and resulting in a high impregnation rate, thus improving the performance of the battery.

[0033] In one embodiment of the present invention, the separation membrane may be sized such that it extends outward from both sides beyond the edges corresponding to the adjacent anode and cathode (hereinafter referred to as the "excess portion") by the width dimension of the separation membrane (perpendicular to the longitudinal dimension in which the separation membrane is extended). Furthermore, the structure is configured such that a coating layer thicker than the thickness of the separation membrane is formed on one or both sides of the excess portion of the separation membrane to prevent shrinkage of the separation membrane. Details regarding the thick coating layer of the excess portion extending outward from the separation membrane refer to Korean Published Patent Publication No. 10-2016-0054219, whose entire contents are incorporated herein by reference. In one embodiment of the present invention, the excess portion of the separation membrane may be 5% to 12% in size based on the width of the separation membrane. Furthermore, in one embodiment of the present invention, the coating layer may be coated on both sides of the separation membrane with a size of 50% to 90% in size based on the width of the excess portion of the separation membrane on one side. Furthermore, the widths of the coating layers on both sides may be the same or different.

[0034] In one embodiment of the present invention, the coating layer may contain inorganic particles and a binder polymer.

[0035] In one embodiment of the present invention, examples of the polyolefin-based separation membrane component include high-density polyethylene, linear low-density polyethylene, low-density polyethylene, ultra-high molecular weight polyethylene, polypropylene, or derivatives thereof.

[0036] In one embodiment of the present invention, the thickness of the coating layer may be less than the thickness of the first electrode or the second electrode. In a specific example, the thickness of the coating layer may be 30% to 99% of the thickness of the first electrode or the second electrode.

[0037] In one embodiment of the present invention, the coating layer may be formed by wet coating or dry coating.

[0038] In one embodiment of the present invention, the substrate and the coating layer exist in an anchoring manner, where the pores on the surface of the polyolefin-based separation membrane substrate and the coating layer are intertwined, allowing the separation membrane substrate and the active layer to be physically strongly bonded. The thickness ratio of the substrate to the active layer of the separation membrane may be 9:1 to 1:9. Preferably, the thickness ratio may be 5:5.

[0039] In one embodiment of the present invention, the inorganic particles may be inorganic particles commonly used in the industry. The inorganic particles interact with each other to form micropores in the form of empty spaces between them, and at the same time can help maintain the physical form of the coating layer. Furthermore, since the inorganic particles generally have the property that their physical properties do not change even at high temperatures of 200°C or higher, the formed porous composite film of inorganic materials will have excellent heat resistance.

[0040] Furthermore, while the materials that can be used for inorganic particles are not particularly limited, they are preferably electrochemically stable materials. That is, the inorganic particles that can be used in the present invention are not particularly limited as long as they do not undergo oxidation and / or reduction reactions within the operating voltage range of the battery to which they are applied (for example, 0 to 5V based on Li / Li+). In particular, when inorganic particles with ion transfer capability are used, the ionic conductivity within the electrochemical element can be increased, thereby improving performance. Therefore, it is preferable to use inorganic particles with the highest possible ionic conductivity. Also, if the inorganic particles have a high density, it becomes difficult to disperse them during coating, which increases the weight of the battery during manufacturing. Therefore, it is preferable to use inorganic particles with the lowest possible density. In addition, in the case of inorganic materials with a high dielectric constant, it can contribute to increasing the degree of dissociation of electrolyte salts, such as lithium salts, in the liquid electrolyte, thereby improving the ionic conductivity of the electrolyte.

[0041] For the reasons stated above, the inorganic particles may be at least one selected from the group consisting of piezoelectric inorganic particles and inorganic particles having lithium ion transport capability.

[0042] The aforementioned piezoelectric inorganic particles are insulators at normal pressure, but when a certain pressure is applied, they become electrically conductive due to a change in their internal structure. They are also materials exhibiting high dielectric constant properties, with a dielectric constant of 100 or more. Piezoelectric inorganic particles are also materials (for example, separation films) that, when stretched or compressed under a certain pressure, generate electric charge, causing one side to become positively charged and the other negatively charged, thereby creating a potential difference between the two sides.

[0043] When inorganic particles having the characteristics described above are used as a coating layer component, if an internal short circuit occurs between the two electrodes due to an external impact such as a needle-shaped conductor, the inorganic particles coated on the separation film may prevent the anode and cathode from making direct contact. Furthermore, the piezoelectric properties of the inorganic particles generate a potential difference within the particles, which causes electron transfer between the two electrodes (i.e., a minute current flow), resulting in a gradual decrease in the battery voltage and thereby improving safety.

[0044] Examples of piezoelectric inorganic particles include BaTiO3, Pb(Zr,Ti)O3(PZT), and Pb 1-x La x Zr 1-y Ti y O3(PLZT), PB(Mg3Nb) 2 / 3 ) may be one or more selected from the group consisting of O3-PbTiO3 (PMN-PT) and hafnia (HfO2), but is not limited to this.

[0045] The inorganic particles having lithium ion transport capability refer to inorganic particles that contain the element lithium but do not store lithium, and instead have the function of transporting lithium ions. These inorganic particles with lithium ion transport capability can transport lithium ions due to a type of defect present within their particle structure. As a result, the lithium ion conductivity in the battery is improved, thereby improving battery performance.

[0046] Examples of inorganic particles having lithium ion transport capability include lithium phosphate (Li3PO4) and lithium titanium phosphate (Li3PO4). x Ti y (PO4)3,0 <x<2、0<y<3)、リチウムアルミニウムチタニウムホスフェート(Li x Al y Ti z (PO4)3,0 <x<2、0<y<1、0<z<3)、(LiAlTiP) x O yIt is glass (0 < x < 4, 0 < y < 13), lithium lanthanum titanate (Li x La y TiO3, 0 < x < 2, 0 < y < 3), lithium germanium thiophosphate (Li x Ge y P z S w , 0 < x < 4, 0 < y < 1, 0 < z < 1, 0 < w < 5), lithium nitride (LixNy, 0 < x < 4, 0 < y < 2), SiS2 (Li x Si y S z , 0 < x < 3, 0 < y < 2, 0 < z < 4) - based glass and P2S5 (Li x P y S z , 0 < x < 3, 0 < y < 3, 0 < z < 7) - based glass, and may be one or more selected from the group consisting of, but not limited to, these.

[0047] The composition ratio of the inorganic particles and the binder polymer constituting the coating layer of the separation membrane is not particularly limited, but can be adjusted within the range of 10:90 to 99:1% by weight, and a range of 80:20 to 99:1% by weight is preferred. When the composition ratio is less than 10:90% by weight, the content of the polymer becomes excessively large, and the pore size and porosity due to the reduction of the empty space formed between the inorganic particles decrease, which may cause a decrease in the performance of the final battery. On the other hand, when it exceeds 99:1% by weight, since the polymer content is too small, the adhesive force between the inorganics weakens, and the mechanical properties of the final organic / inorganic composite porous separation membrane may decrease.

[0048] In one embodiment of the present invention, the binder polymer may be a binder polymer generally used in the art.

[0049] Among the above organic / inorganic composite porous separation membranes, the coating layer may further contain other commonly known additives in addition to the aforementioned inorganic particles and binder polymer.

[0050] In one embodiment of the present invention, the coating layer can also be said to be an active layer.

[0051] As described above, after the electrode assembly 10 is assembled, and before the electrode assembly 10 is further manufactured (e.g., moved to a battery case), a press unit applies heat and pressure to the laminate to bond the components together. Such application of heat and pressure may be carried out in several stages, including an initial primary heat press stage followed by a secondary heat press operation. To carry out such heat press stages, a press unit as shown in Figures 6(a) and 6(b) may be provided.

[0052] Referring to Figure 6(a), the first press section 50 can pressurize the laminate S in a temporarily heated and fixed state. The first press section 50 includes a pair of first pressurizing blocks 50a and 50b, and may further include a gripper 51 capable of fixing the laminate S. In fixing the laminate S, the gripper 51 can fix the laminate S by pressing the upper and lower surfaces of the laminate S against each other along the lamination direction Y in order to fix the relative positions of the first electrode 1, the second electrode 2, and the separation membrane 4.

[0053] The pair of first pressure blocks 50a and 50b of the first press section 50 may move toward each other or toward each other. When the pair of first pressure blocks 50a and 50b move toward each other, they can compress either the laminate S or the gripper 51 or both.

[0054] In one embodiment, the first pressing unit 50 may heat and pressurize the laminate S to reduce or eliminate the spaces between the first electrode 1, the separation membrane 4, and the second electrode 12 contained in the laminate S, thereby bonding these components of the laminate S together.

[0055] As illustrated, the pressing surfaces of the pair of first pressure blocks 50a, 50b configured for contact with and pressurizing the laminate S may be planar. At least one of the pair of first pressure blocks 50a, 50b may include a gripper groove 52 shaped to correspond to the fixing portion 51b of the gripper 51 described later. In the example shown in Figure 6(a), each of the pair of first pressure blocks 50a, 50b includes four gripper grooves 52 corresponding to four fixing portions 51b. However, the number of gripper grooves 52 may be more or less. Preferably, the number of gripper grooves 52 should match the number of fixing components used.

[0056] The gripper 51 may include a main body 51a and a plurality of fixing parts 51b. The main body 51a may have a length along the x-axis and a height along the y-axis that is the same as or approximately the same as the length and height of the laminate S along each axis, as shown in the illustrated arrangement. In one embodiment, the main body 51a may have a length greater than the length of the laminate S along the x-axis and a height greater than the height of the laminate S along the y-axis. The fixing parts 51b may preferably be rods, columns, or plates extending along the width direction (z-axis) of the laminate S. Here, the length along the x-axis of the laminate S means the longest distance from one end to the other of the laminate S, and the height along the y-axis may mean the distance in the direction of the laminate S. The width along the z-axis, the stacking direction of the laminate S, may mean the distance in the direction perpendicular to both the x-axis and the y-axis.

[0057] The fixing portion 51b may be arranged in two rows such that one row is adjacent to the pressure surface of the pressure block 50a and the other row is adjacent to the pressure surface of the pressure block 50b. The position of each fixing portion 51b may be adjusted in the height direction of the main body 51a. In this way, each fixing portion 51b can fix the relative positions of the first electrode 1 and the second electrode 12 within the laminate S and the position of the laminate S, preferably along the upper and lower surfaces of the laminate S and its width.

[0058] In one embodiment, during operation, the first press unit 50 may use a pair of pressure blocks 50a and 50b to compress the laminate S for 5 to 20 seconds in an environment where the ambient temperature is 45°C to 75°C and the pressure is 1 MPa to 2.5 MPa.

[0059] In one embodiment, the second pressing section 60 may further compress the laminate S, which has already been heated and compressed by the first pressing section 50, by heating and pressurizing it.

[0060] As shown in Figure 6(b), the second press section 60 includes a pair of second pressure blocks 60a and 60b. The pair of pressure blocks 60a and 60b may move toward each other or toward each other. The pair of pressure blocks 60a and 60b can compress the laminate by applying pressure to the upper and lower surfaces of the laminate S while moving toward each other.

[0061] As shown in the illustration, the respective pressurized surfaces of the pair of second pressurized blocks 60a, 60b configured for contact with and compression of the laminate S may be planar. In one embodiment, as shown in the illustrated example, grooves such as grooves for the fixing portion 51b may be excluded from the second pressurized blocks 60a, 60b. In other embodiments, at least one of the pair of second pressurized blocks 60a, 60b may include one or more grooves shaped to correspond to the fixing portion 51b of the gripper 51.

[0062] In one embodiment, during operation, the second press section 60 can compress the laminate that has been primarily compressed by the first press section 50 for a range of 5 to 60 seconds under temperature conditions of 50°C to 90°C and pressure conditions of 1 MPa to 6 MPa. In one embodiment, the second press section 60 may heat and pressurize only a portion of the laminate S where the gripper 51, which is not heated and pressurized by the first press section 50, is located (or previously). In another embodiment, the second press section 50 may heat and pressurize the entire top and bottom surfaces of the laminate.

[0063] In one embodiment, the first pressing unit 50 can initially compress the heated laminate S to bond together components contained in the laminate S where the gripper 51 is not located, and fix the upper and lower surfaces of the laminate S with the gripper 51, thereby reducing or eliminating the space between the first electrode 1, the separation membrane 4, and the second electrode 12 during bonding.

[0064] In one embodiment, the second press section 60 can pressurize and heat the laminate S that has been pre-bonded by the first press section 50 and from which the gripper 51 has been removed. Therefore, in order to bond together such components of the laminate S in the region of the laminate S that the gripper 51 previously pressed during the initial pressurizing operation by the first press section 50, the second press section 60 can reduce or eliminate the space between the first electrode 1, the separation membrane 4 and the second electrode 12 contained in the laminate S. In one embodiment, each of the pair of second pressurizing blocks 60a, 60b may be a rectangular block in the shape of a hexahedron. In one embodiment, the pair of second pressurizing blocks 60a, 60b may have the flat pressurizing surfaces described above.

[0065] In one embodiment, each of the pair of first pressure blocks 50a and 50b of the first press section 50 may have a flat pressure surface. In one embodiment, each of the pair of second pressure blocks 60a and 60b of the second press section 60 may have a groove having a shape corresponding to the fixing portion 51b of the gripper 51.

[0066] In one embodiment, the fixing portion 51b may include a thermally conductive material such as a thermally conductive metallic substance selected from the group consisting of aluminum and iron. By conducting heat to the laminate S, when the first pressing portion 50 compresses the laminate S fixed by the gripper 51, the space between the electrodes 11, 12 and the separation membrane 4 is reduced or eliminated, thereby allowing them to bond.

[0067] In one embodiment, the second pressing section 60 may not compress the region of the laminate S where the gripper 51 was previously located, but instead compress only the region of the laminate S where the gripper was not previously located and the region that the first pressing section 50 has not pressed.

[0068] Furthermore, the pair of first pressure blocks 50a and 50b may each be a rectangular block in the shape of a right hexahedron. In one embodiment, the pair of first pressure blocks 50a and 50b may have the flat pressure surfaces described above.

[0069] Either one or both of the first and second pressing sections 50, 60 may include a press heater (not shown) and be configured to heat a portion of the laminate S and the separation membrane 4 of the first and second electrodes 1 when each pair of first and second pressing blocks 50a, 50b, 60a, 60b pressurizes the laminate. In this way, when the laminate S is pressed by the first and second pressing sections 50, 60, thermal fusion between the first electrode 1, the separation membrane 4 and the second electrode 2 is more firmly established, and a stronger bond can be formed between these layers.

[0070] When the laminate S is pressurized by the heated press section, the inside of the outermost outer separation membrane 5 surrounding the laminate S can be bonded not only to the adjacent portion of the winding separation membrane 4 (for example, the folding portion P), but also to the side edges 6 of the first and second electrodes 1 and 2 that are exposed in the lateral Z direction on the adjacent outer separation membrane 5, through openings characterized by the absence of the folding portion P.

[0071] Therefore, by bonding the components of the electrode assembly 10 in this manner, loosening of the laminate S's folding can be prevented, improving the stability of the battery. Furthermore, separate adhesive tapes or tools for preventing loosening of the laminate S become unnecessary, shortening manufacturing time and improving process efficiency.

[0072] At least one external surface of the laminate S according to the present invention may include two or more patterns having different properties or heights from other areas on that surface.

[0073] In one embodiment, referring to Figures 4 and 5, the surface of the laminate S may include a first region P1 and a second region P2 having different properties or heights on its surface. For example, the first region P1 may be a region joined by a gripper (e.g., a gripper 51, specifically the fixed portion 51b of the gripper), and the second region P2 may be a region not joined by a gripper. Therefore, the width of the first region P1 may correspond to the width of the gripper, specifically the width of the fixed portion 51b of the gripper.

[0074] The first region P1 and the second region P2 may appear when the laminate S is pressed by the gripper during the process operation described above.

[0075] The separation film 4 contained in the laminate S of the electrode assembly has very little binder component and may have low adhesive strength. Therefore, when the laminate S is pressurized, the first electrode 1 and the second electrode 2 may be deformed by the pressure applied to the laminate S.

[0076] Therefore, the electrode assembly 10 according to the present invention may be manufactured by first pressing the upper and lower surfaces of the laminate S with grippers to fix the first electrode 1 and the second electrode 2, and then second pressing after removing the grippers.

[0077] As a result, the first region P1 and the second region P2 may differ in at least one of their properties and heights. In one example, the property may be the shading or hue of at least one surface of the laminate. In other examples, the property may be the permeability of the separation membrane 4 or the adhesive force between the electrodes and the separation membrane. The adhesive force may mean the amount of force required to peel the separation membrane 4 from the electrodes 1 and 2.

[0078] It may include two or more first regions P1 and two or more second regions P2. Furthermore, multiple first regions P1 may be spaced apart from each other, and multiple second regions P2 may also be spaced apart from each other.

[0079] In one embodiment, the number of first regions P1 may be less than the number of second regions P2. For example, if the number of first regions P1 in the electrode assembly 10 is N (where N is a positive integer excluding 0), the number of second regions P2 may be N+1.

[0080] The first region P1 and the second region P2 can be alternately positioned along the width direction X of the electrode assembly 10 or the laminate S. Furthermore, at least one boundary of the first region P1 may be in contact with at least one boundary of the second region P2.

[0081] In the electrode assembly 10 according to the present invention, the portion of the gripper 51 (specifically, the fixed portion 51b of the gripper) that engages with the upper and / or lower surface of the laminate S may have a darker shadow than the portion of the gripper 51 that does not engage with the gripper 51 while the portion of the gripper 51 that engages with the gripper 51 is heat-pressed by the first press unit 50. In this embodiment, the portion of the fixed portion 51b of the gripper 51 that engages with the gripper is the first region P1, and the portion of the fixed portion 51b of the gripper 51 that does not engage with the gripper is the second region P2.

[0082] Furthermore, the electrode assembly 10 according to the present invention may include a step between the first region P1 and the second region P2. That is, the height of the upper and / or lower surface portion of the laminate S that engages with the gripper 51 (particularly the fixing portion 51b of the gripper) may be different from the height of the upper and / or lower surface portion of the laminate S that does not engage with the fixing portion 51b of the gripper 51. If the portion that engages with the gripper is the first region P1 and the portion that does not engage with the gripper is the second region P2, the surface of the electrode assembly 10 may include a surface step, and the first region P1 may be higher than the second region.

[0083] In the electrode assembly 10, the width of the first region P1 may be smaller than the width of the second region P2. That is, if the total area of ​​one surface of the laminate S including the first region P1 and the second region P2 is taken as 100%, the area of ​​the first region P1 may be 30% to 50% of the total area of ​​that surface.

[0084] The electrode assembly 10 according to the present invention minimizes the width of the components of the gripper 51 that engage with the electrode assembly 10, thereby minimizing the deviation in characteristics or height between the first region P1 and the second region P2. When the variation in characteristics or height between the first region P1 and the second region P2 is minimized, the overall characteristics or height of the electrode assembly 10 can become more uniform.

[0085] Furthermore, if the area of ​​the first region P1 is less than 30% of the area of ​​one surface of the laminate S, there is a higher probability that the electrodes of the electrode assembly 10 will move before they are fixed by bonding. Consequently, the energy density of the electrode assembly will be lower. On the other hand, if the area of ​​the first region P1 exceeds 50% of the area of ​​one surface of the laminate S, a problem may arise in which the bonding of the components within the laminate S cannot secure the desired minimum adhesive strength.

[0086] Furthermore, the surface on which the pattern is formed may be the top surface, bottom surface, or both the top and bottom surfaces of the laminate S, starting from both ends of the laminate S in the stacking direction.

[0087] In this specification, "adhesion" means the adhesion between the first electrode 1 and the separation membrane, or between the second electrode 2 and the separation membrane. The method for measuring the adhesion of the separation membrane according to the present invention is not particularly limited. According to one measurement method, a sample with a width of 55 mm and a length of 20 mm is adhered to each glass slide, and the electrodes are positioned on the adhesive surface of the glass slide. Then, each sample is tested by performing a 90° peel test at a speed of 100 mm / min according to the test method specified in ASTM-D6862. That is, the edge of the separation membrane is pulled 90° upward relative to the glass slide at a speed of 100 mm / min to peel the separation membrane from the electrode along the width direction of the sample (i.e., peeled from 0 mm to 55 mm). Using this test method, the adhesive strength between the electrode and the separation membrane in the first region P1 (hereinafter referred to as the adhesive strength of the first region P1) may be 3gf / 20mm to 25gf / 20mm, and the adhesive strength between the electrode and the separation membrane in the second region P2 (hereinafter referred to as the adhesive strength of the second region P2) may be 4gf / 20mm to 30gf / 20mm.

[0088] The difference in adhesive strength between the separation membrane 4 and electrodes 1 and 2 in the first region P1 and the second region P2 may be between 0.1 gf / 20 mm and 11 gf / 20 mm.

[0089] According to one embodiment of the present invention, referring to Figure 2, the intermediate adhesive force of the first region P1 of the electrode assembly (i.e., the adhesive force of one region) may be 3gf / 20mm to 10gf / 20mm, preferably 5gf / 20mm to 6gf / 20mm.

[0090] According to one embodiment of the present invention, the upper surface adhesive force of the first region P1 of the electrode assembly (i.e., the adhesive force of region 1 in Figure 2) may be 8gf / 20mm to 20gf / 20mm, preferably 9gf / 20mm to 14gf / 20mm.

[0091] According to one embodiment of the present invention, the adhesive force on the lower surface of the first region P1 of the electrode assembly (i.e., the adhesive force in the three regions of Figure 2) may be 9gf / 20mm to 25gf / 20mm, preferably 9gf / 20mm to 12gf / 20mm.

[0092] According to one embodiment of the present invention, the intermediate adhesive force of the second region P2 of the electrode assembly may be 4gf / 20mm to 15gf / 20mm, preferably 5gf / 20mm to 11gf / 20mm.

[0093] According to one embodiment of the present invention, the upper surface adhesive force of the second region P2 of the electrode assembly may be 5gf / 20mm to 25gf / 20mm, preferably 7gf / 20mm to 21gf / 20mm.

[0094] According to one embodiment of the present invention, the adhesive force on the lower surface of the second region P2 of the electrode assembly may be 7gf / 20mm to 30gf / 20mm, preferably 10gf / 20mm to 22gf / 20mm.

[0095] According to one embodiment of the present invention, the adhesive force between the anode and the separation membrane and the adhesive force between the cathode and the separation membrane may be the same or different.

[0096] If the adhesive strength between the first region P1 and the second region P2 is less than 4gf / 20mm, the adhesive strength of the electrode assembly 10 will be low, and the folding may loosen when the electrode assembly 10 or the laminate S moves during the manufacturing process, potentially causing a folding phenomenon of the separation membrane 4.

[0097] If the adhesive strength of the first region P1 exceeds 15 gf / 20 mm and the adhesive strength of the second region P2 exceeds 26 gf / 20 mm, the permeability and impregnation of the separation membrane 4 will decrease, making it difficult for the electrolyte to penetrate into the electrode assembly 10, which may reduce the initial volume of the electrode assembly 10 and increase its initial resistance.

[0098] In this invention, the "air permeability" of the electrode assembly refers to the air permeability of the separation membrane 4 of the electrode assembly 10.

[0099] The method for measuring the permeability of the separation membrane in this invention is not particularly limited. In the methods used herein and further discussed herein, permeability was measured using a Toyoseiki Gurley type densometer (No. 158) according to a method commonly used in the industry, namely the Japanese Industrial Standard Gurley (JIS) measurement method. Specifically, the permeability of the separator was determined by measuring the time it took for 100 ml (or 100 cc) of air to pass through a 1 square inch separation membrane at room temperature (i.e., 20°C to 25°C) at a pressure of 0.05 MPa.

[0100] Unless otherwise specified, "air permeability" refers to the air permeability of all separation membranes within the electrode assembly, and the air permeability of each separation membrane may be the same or different, independently of each other. Furthermore, as mentioned above, top air permeability, bottom air permeability, and intermediate air permeability may be defined depending on the position of the electrode assembly.

[0101] The difference in air permeability between the first zone P1 and the second zone P2 may be between 2 seconds / 100ml and 25 seconds / 100ml.

[0102] According to one embodiment of the present invention, the intermediate air permeability of the first region P1 of the electrode assembly may be 70 seconds / 100ml to 90 seconds / 100ml, preferably 75 seconds / 100ml to 86 seconds / 100ml.

[0103] According to one embodiment of the present invention, the upper surface air permeability of the first region P1 of the electrode assembly may be 80 seconds / 100ml to 110 seconds / 100ml, preferably 80 seconds / 100ml to 98 seconds / 100ml.

[0104] According to one embodiment of the present invention, the air permeability of the lower surface of the first region P1 of the electrode assembly may be 80 seconds / 100 ml to 110 seconds / 110 ml, preferably 80 seconds / 100 ml to 98 seconds / 100 ml.

[0105] According to one embodiment of the present invention, the intermediate air permeability of the second region P2 of the electrode assembly may be 70 seconds / 100ml to 100 seconds / 100ml, preferably 75 seconds / 100ml to 84 seconds / 100ml.

[0106] According to one embodiment of the present invention, the upper surface air permeability of the second region P2 of the electrode assembly may be 80 seconds / 100ml to 110 seconds / 100ml, preferably 84 seconds / 100ml to 101 seconds / 100ml.

[0107] According to one embodiment of the present invention, the air permeability of the lower surface of the second region P2 of the electrode assembly may be 80 seconds / 100ml to 110 seconds / 100ml, preferably 84 seconds / 100ml to 101 seconds / 100ml.

[0108] According to one embodiment of the present invention, the lower air permeability may be the same as or less than the upper air permeability. Also, the intermediate air permeability may be the same as or less than the lower air permeability. That is, the magnitudes of the upper air permeability, lower air permeability, and intermediate air permeability can satisfy the following formula 1.

[0109] [Formula 1] Top surface ventilation ≥ Bottom surface ventilation ≥ Intermediate ventilation

[0110] The result of Equation 1 represents the result of the heating and pressurizing process of the electrodes and separation membrane, and the pressure generated when the electrodes and separation membrane are stacked.

[0111] According to one embodiment of the present invention, if the permeability of the separation membrane 4 in the first region P1 and the second region P2 is less than 70 sec / 100 ml, the impregnation of the electrolyte is poor, the ion movement path is blocked, and the performance of the electrode assembly 10 may be reduced. If the permeability of the separation membrane 4 in the first region P1 and the second region P2 exceeds 110 sec / 100 ml, the adhesion between the first electrode 1 and the second electrode 2 and the separation membrane decreases, and the first and second electrodes 1 and 2 of the electrode assembly 10 may protrude and protrude to the surface of the battery.

[0112] While preferred embodiments of the present invention have been described above with reference to those skilled in the art, it will be understood that various modifications and changes can be made to the present invention without departing from the spirit and scope of the invention as set forth in the following claims.

[0113] Examples 1) Example 1 Nineteen anodes, twenty cathodes, and a separation membrane were stacked on a stacking table S.

[0114] More specifically, the anode and cathode were supplied in the form of cut anode sheets and cathode sheets, respectively, and the separation membrane was supplied in the form of a separation membrane sheet. Then, the supplied separation membrane was folded while the stacking table was rotated, and the anode, cathode, and separation membrane were stacked. At this time, in order to fix the position of the stacked product S with respect to the stacking table, the top surface of the stacked product S was pressed downward toward the stacking table using a gripper while stacking was performed.

[0115] After manufacturing the laminate, the laminate was gripped with a gripper, and the first heat press stage was carried out by heating the laminate at an ambient temperature of 70°C and a pressure of 1.91 MPa while applying pressure to the laminate using the first press section 50 for 15 seconds.

[0116] After the first heat press step, the gripper was released from the laminate, the temperature of the second press section 60 was heated to 70°C (temperature condition), and the electrode assembly of Example 1 was manufactured through a second heat press step in which a pressure of 2.71 MPa (pressure condition) was applied to the laminate with the press's pressure block for 10 seconds (press time).

[0117] The above-described disclosures of the present invention may be applied during the manufacturing process of the electrode assembly.

[0118] 2) Examples 2-12 The electrode assemblies of Examples 2 to 12 were manufactured in the same manner as in Example 1, except that the second heat press stage was performed under the temperature, pressure, and pressing time conditions listed in Table 1 below. In other words, the first heat press conditions for Examples 1 to 12 were the same.

[0119] [Table 1]

[0120] 3) Comparative Examples 1-5 The electrode assemblies of Comparative Examples 1 to 5 were manufactured in the same manner as in Example 1, except that the first heat press stage was performed under the temperature, pressure, and pressing time conditions listed in Table 2 below, and the second heat press stage was not carried out.

[0121] [Table 2]

[0122] The electrode assemblies of Examples 1-12 and Comparative Examples 1-5, manufactured under the conditions of Tables 1 and 2, were all picked up and tested using a vacuum suction mechanism. In all of the electrode assemblies of Comparative Examples 2-5, it was observed that the electrodes and separation membranes separated within 60 seconds.

[0123] In other words, while the electrode assemblies of Comparative Examples 1 to 5 have poor adhesion between the electrode and the separation membrane, the electrode assemblies according to this application (first and second pressing processes) exhibit good adhesion. Therefore, they have an excellent effect in preventing loosening and detachment of the electrode assemblies.

[0124] In Comparative Examples 6 and 7, the separation of the electrode and the separation membrane was not observed before 60 seconds, but damage to the electrode assembly was confirmed. This is presumed to have occurred because the primary press was carried out under a pressure condition of 2.54 MPa (high pressure).

[0125] 4) Experimental Example 1 - Evaluation of Adhesion Strength and Dielectric Strength After disassembling (i.e., separating the layers) the electrode assemblies of Examples 1-12 and Comparative Examples 6 and 7 (where separation of the electrode and separation membrane was not observed before 60 seconds in previous tests), the separated layers were analyzed to measure the adhesive strength between the upper end, lower end, and intermediate surface of the laminate S. Specifically, the adhesive strength between the separation membrane located at the bottom end of the laminate and the cathode was measured. The adhesive strength between the cathode located at the top end of the laminate and the separation membrane was also measured. Finally, the adhesive strength between the cathode located at an intermediate point along the lamination direction of the laminate and the separation membrane was measured.

[0126] The cathode and separation membrane samples taken from each separated electrode assembly were 55 mm wide and 20 mm long. The sampled samples were bonded to a glass slide so that the electrodes were positioned on the adhesive surface of the slide. The glass slides with the attached specimens were then mounted on an adhesion force measuring device and tested with a 90° peel test at a speed of 100 mm / min according to the test method specified in ASTM-D6862, as discussed earlier. After ignoring any initial violent fluctuations, the force (g / mm) applied per sample width while the separation membrane peeled from the electrode was measured.

[0127] The results are shown in Table 3 below.

[0128] [Table 3]

[0129] Furthermore, the dielectric strength of the electrode assemblies of Examples 1, 6, and 12 and Comparative Examples 1 to 7 was also measured.

[0130] The results are shown in Table 4 below. [Table 4]

[0131] As can be seen from the results in Table 4, the adhesive strength of Examples 1, 6, and 12 was found to be superior to that of Comparative Example 1, which was performed under similar conditions to the examples but only in the first heat press stage.

[0132] Furthermore, the results in Table 4 confirm that the withstand voltage of Examples 1, 6, and 12, which underwent the first heat pressing stage under higher temperature and pressure conditions than the comparative examples, was in the range of 1.56kV to 1.8kV.

[0133] In other words, the electrode assembly of the present invention has excellent adhesive strength and also possesses characteristics suitable for use as an electrode assembly, and we were able to confirm that it has a voltage resistance of 1.8kV or less.

[0134] This is determined to be because the electrode assembly was manufactured using a manufacturing method that included both the first and second heat pressing stages.

[0135] 5) Experimental Example 2 - Evaluation of Air Permeability The air permeability of the electrode assemblies of Examples 1, 6, and 12, and Comparative Example 1, which differed only in the temperature conditions of the second press, was evaluated.

[0136] Specifically, after collecting the separation membranes from the electrode assemblies of Examples 1, 6, and 12, the separation membranes were cut to prepare 5cm x 5cm (width x height) separation membrane samples. These separation membrane samples were then washed with acetone.

[0137] Subsequently, the air permeability of Examples 1, 6, and 12 was measured using a Toyoseiki Gurley type densometer (No. 158) in accordance with the Japanese Industrial Standard (JIS) Gurley measurement method, by measuring the time it took for 100 ml (or 100 cc) of air to pass through a 1 square inch of the separation membrane at room temperature and a pressure of 0.05 MPa.

[0138] The results are shown in Table 5. [Table 5]

[0139] From the results in Table 5 above, it was confirmed that when the second heat press conditions according to the present invention are met, the air permeability at each position is less than 120 sec / 100 ml, which is a level of air permeability suitable for use as an electrode assembly. Furthermore, it was confirmed that the deviation in air permeability at each position is less than 20 sec / 100 ml, which is a level of air permeability deviation that can be judged as uniform. In other words, it was confirmed once again that the electrode assembly manufactured by the manufacturing method according to the present invention has uniform performance.

[0140] Furthermore, it was confirmed that the variation in air permeability at each location was less than 20 sec / 100 ml, indicating a uniform level of air permeability variation.

[0141] In particular, it was confirmed that the air permeability deviation was smallest in Example 1, where the temperature condition was 70°C.

[0142] Through the aforementioned experimental examples, it was confirmed that the electrode assembly according to the present invention has appropriate and uniform air permeability and adhesive strength.

[0143] On the other hand, in Comparative Example 1, although the variation in air permeability at each position was smaller than in the Examples, the top surface air permeability and bottom surface air permeability were independently less than 80 sec / 100 ml, confirming that it was less safe than the electrode assembly according to the present invention. This is judged to be because, unlike the manufacturing process of the electrode assembly according to the present invention, only the first heat press was performed.

Claims

1. It includes multiple electrodes arranged in the laminate along the stacking axis, Each electrode within the laminate is separated from one of the electrodes within the laminate by a separation membrane located between them along the lamination axis. At least one external surface of the laminate includes a pattern composed of a first region and a second region. The second portion of the laminate corresponding to the second region has different characteristics or height from the first portion of the laminate corresponding to the first region. The separation membrane is adhered to the electrode and has a peeling force applied to one edge of the separation membrane in order to peel one of the separation membranes from each of the electrodes to which it is adhered along the stacking axis at a speed of 100 mm / min. The peeling force in the first portion corresponding to the first region is different from the peeling force in the second portion corresponding to the second region. An electrode assembly in which the difference in peeling force between the first and second parts is 0.1 gf / 20 mm to 11 gf / 20 mm.

2. The second portion of the laminate corresponding to the second region has different characteristics from the first portion of the laminate corresponding to the first region. The electrode assembly according to claim 1, wherein the characteristics include any of the shading, hue, permeability of the separation membrane portion between the first and second regions, and adhesive force between the electrodes and the separation membrane portion between the first and second regions.

3. The electrode assembly according to claim 1, wherein at least one outer surface of the laminate containing the pattern is the top surface, bottom surface, or both the top and bottom surface of the laminate, from opposing sides of the laminate along the lamination axis.

4. The aforementioned pattern includes two or more of the first region and two or more of the second region, The electrode assembly according to claim 1, wherein the first region is spaced apart from each other, and the second region is spaced apart from each other.

5. The first region and the second region are alternately located along the width direction of the laminate, The electrode assembly according to claim 1, wherein the width direction intersects the stacking axis.

6. The electrode assembly according to claim 1, wherein the first region has a width smaller than the width of the second region.

7. The electrode assembly according to claim 1, wherein the pattern includes a plurality of second regions, and the number of first regions is less than the number of second regions.

8. The separation membrane has an air permeability of 100 ml / sec per square inch of each separation membrane at a pressure of 0.05 MPa. The electrode assembly according to claim 1, wherein the permeability value of the separation membrane of the first portion corresponding to the first region is different from the permeability value of the separation membrane of the second portion corresponding to the second region, and the difference in air permeability between the first portion and the second portion is 2 seconds / 100 ml to 25 seconds / 100 ml.

9. The separation membrane is provided by an extended separation membrane sheet, which is folded between each of the separation membranes so as to extend between electrodes continuous from the stacking axis along a winding path that traverses front to back along a transverse direction perpendicular to the stacking axis. The electrode assembly according to claim 1, wherein each electrode in the laminate includes a first side end and a second side end on the side surfaces of each electrode facing each other in the lateral direction.

10. The electrode assembly according to claim 9, wherein the laminate further comprises an external separation membrane surrounding the laminate.

11. The electrode assembly according to claim 10, wherein the external separation membrane is integral with the separation membrane.

12. The electrode assembly according to claim 10, wherein the inside of the outer separation membrane is thermally bonded to the folding portion of the extended separation membrane or to at least one of the first side edge or second side edge of at least one electrode of the laminate.

13. The electrode assembly according to claim 1, wherein each electrode in the laminate is thermally bonded to one of the adjacent separation membranes.

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